Welcome to my Midget Mustang builder's log. I haven't seen many on-line builder's logs for the MM1, so I thought I'd do my part to add to the list. To anyone building (or considering it) a Midget Mustang, I hope you will find something useful in this "blog." If you are simply interested in my progress, I thank-you for your interest.
Please note: I will make my best effort to place notices in various sections of this blog to make it clear that anything shown in images, drawings, or in the text of this blog page shall not be interpreted as a recommendation, or an official modification – only as an indication of what the builder did.
Please note: I will make my best effort to place notices in various sections of this blog to make it clear that anything shown in images, drawings, or in the text of this blog page shall not be interpreted as a recommendation, or an official modification – only as an indication of what the builder did.
David Long, 1948 Lockhaven, PA
Abbreviations:
FS - Fuselage Station (measured in inches from a reference point at the front of the aircraft)
BH - Bulkhead (structure used to form & maintain the cross-sectional dimensions of the fuselage at a given FS)
C/L - Center Line (line drawn though the geometric center of a given cross-section)
LHS - Left Hand Side
RHS - Right Hand Side
C/S - Countersink (or Countersunk)
IP - Instrument Panel
GW - Gross Weight
MMD - Measure, mark, & drill
BH - Bulkhead (structure used to form & maintain the cross-sectional dimensions of the fuselage at a given FS)
C/L - Center Line (line drawn though the geometric center of a given cross-section)
LHS - Left Hand Side
RHS - Right Hand Side
C/S - Countersink (or Countersunk)
IP - Instrument Panel
GW - Gross Weight
MMD - Measure, mark, & drill
11 May 2011
Today, I took the plunge. I placed the order for the tail cone, empennage, and rivet kit. I have already purchased the drawings and have been looking them over for a few months.
22 May 2011 (2 hours, total time to date: 2 hours)
Began work on the tail cone jig as shown in the drawings. Purchased 2x6 lumber and developed a detailed construction plan.
23 May 2011 (1 hour, total time to date: 3 Hours)
Fastened 2x6 jig frames in an “L” section & added the cross member at the far end
24 May 2011 (1.5 hours, total time to date: 4.5 hours)
Laid out gusset reinforcements on the jig. The vertical support spacing is called out in the drawings.
25 May 2011 (1.5 hours, total time to date: 6 hours)
Aligned jig vertically and began attaching gussets.
26 May 2011 (1.5 hours, total time to date: 7.5 hours)
Finished attaching gussets.
27 May 2011 (1.5 hours, total time to date: 9 hours)
Glued 1x2 finishing strips to be used as 2x2 vertical supports on the tail cone jig.
28 May 2011 (1.5 hours, total time to date: 10.5 hours)
Cut vertical supports to rough length and laid out on the jig.
28 Sep 2011 (1.5 hours, total time to date: 12 hours)
Started work to align & attach the vertical rear tail cone alignment support.
29 Sep 2011 (1.5 hours, total time to date: 13.5 hours)
Cut Masonite shear webs to provide forward & aft shear stiffness for the rear vertical support.
30 Sep 2011 (1.5 hours, total time to date: 15 hours)
Cut 1x2 furring strips to be used to provide stability to the shear webs
1 Oct 2011 (2 hours, total time to date: 17 hours)
Fastened webs & furring strips to complete the rear tail alignment support.
28 Oct 2011 (0 hours, total time to date: 17 hours)
Received the tail cone, empennage, & rivet kits. My friend, Alex, helped me pick up the kits that had been delivered to a local freight company.
27 Nov 2011 (3 hours, total time to date: 20 hours)
Began work to position, align, and attach vertical supports for the tail cone bulkheads. Used 3 inch long, 1/4 inch lag screws to attach the vertical supports to the jig base.
3 Dec 2011 (3 hours, total time to date: 23 hours)
Finished attachment of FS177.5 bulkhead support & started work on FS160 B/H support.
4 Dec 2011 (3 hours, total time to date: 26 hours)
Finished attachment of FS160 support & began work on FS128 B/H support.
5 Dec 2011 (2 hours, total time to date: 28 hours)
Continued work on FS128 B/H support.
6 Dec 2011 (2 hours, total time to date: 30 hours)
Finished attachment of FS128 B/H support & attached additional support gusset on the jig.
7 Dec 2011 (1.5 hours, total time to date: 31.5 hours)
Started work to align & attach the vertical front tail cone alignment support
9 Dec 2011 (1.5 hours, total time to date: 33 hours)
Finished mounting the front alignment support.
10 Dec 2011 (2 hours, total time to date: 35 hours)
Added Masonite web and side brace to the front alignment support
11 Dec 2011 (3 hours, total time to date: 38 hours)
Attached additional side braces to stiffen BH160 & 128 vertical supports
12 Dec 2011 (1.5 hours, total time to date: 39.5 hours)
.Began mounting BH99.5 bulkhead supports
13 Dec 2011 (1 hour, total time to date: 40.5 hours)
Finished mounting the left vertical support.
14 Dec 2011 (1.5 hours, total time to date: 42 hours)
Mounted the right vertical support.
15 Dec 2011 (2 hours, total time to date: 44 hours)
Added an angle brace, cut 6061 lower angle brace to size, and fabricated 0.125 thick washers for the brace attach bolts and to help prevent twisting of the vertical supports.
16 Dec 2011 (1 hour, total time to date: 45 hours)
Attached lower angle brace and cut the upper 6061 angle brace to size.
17 Dec 2011 (3 hours, total time to date: 48 hours)
Attached the upper angle brace and began work on an additional diagonal (shear) support for BH99.35.
18 Dec 2011 (3 hours, total time to date: 51 hours)
Finished alignment and attachment of the additional shear support.
19 Dec 2011 (1 hour, total time to date: 52 hours)
Fabricated 0.125 thick 2024 plates to align and mount the horizontal center line wire
20 Dec 2011 (2 hours, total time to date: 54 hours)
Used a laser pointer and spirit level to position and mount the front & rear wire plates to the front and rear alignment supports.
22 Dec 2011 (1.5 hours, total time to date: 55.5 hours)
Added a second side brace for the front alignment support to provide additional rigidity.
23 Dec 2011 (1.5 hours, total time to date: 57 hours)
Cut 1x2 strips to be used to attach to the additional front vertical support and the upper brace angle to provide final fore and aft alignment adjustments to the FS99.5 vertical supports.
24 Dec 2011 (2 hours, total time to date: 59 hours)
Rechecked jig alignment and made final adjustments to the support structure.
26 Dec 2011 (1.5 hours, total time to date: 60.5 hours)
Drilled attachment holes in FS177.5 2024-T3 reinforcing plate & match drilled the plate to the tail cone bulkhead.
27 Dec 2011 (1.5 hours, total time to date: 62 hours)
Drilled attachment holes in FS177.5 4340 Steel tail wheel attach fitting & match drilled the BH
28 Dec 2011 (2 hours, total time to date: 64 hours)
Began work to fabricate a 0.032 thick 2024-T3 doubler around the tail wheel fitting for the FS177.5 BH to reduce risk of cracking in the skin around the tail wheel attachment. This will add another load path from the tail wheel fitting to the tail cone skin. Forming blocks were cut from furniture grade plywood.
Note: This is not a recommendation, nor an official modification – only indication of what the builder did.
29 Dec 2011 (2.5 hours, total time to date: 66.5 hours)
Modified the FS177.5 BH forming blocks to add flute cut-outs & made a prototype doubler.
30 Dec 2011 (2 hours, total time to date: 68.5 hours)
Made minor adjustments to the prototype doubler, and cut out new sheet metal blanks.
31 Dec 2011 (2 hours, total time to date: 70.5 hours)
Fabricated the (0.032 thick 2024-T3) doubler (and spares) for use on the A/C.
1 Jan 2012 (1.5 hours, total time to date: 72 hours)
Began work to fabricate a 0.032 thick 2024-T3 FS182 BH doubler to reduce risk of skin cracking around the tail wheel attachment at that location.
2 Jan 2012 (2 hours, total time to date: 74 hours)
Finished work to fabricate forming blocks for the FS182 BH doubler.
3 Jan 2012 (1.5 hours, total time to date: 75.5 hours)
Cut (0.032, 2024-T3) sheet metal blanks in preparation to form the doubler (and spares).
4 Jan 2012 (1 hour, total time to date: 76.5 hours)
Fabricated a prototype duplicate of FS182 BH
5 Jan 2012 (1 hour, total time to date: 77.5 hours)
Fabricated a prototype doubler for FS182 to fit around the steel tail wheel attach fitting on that BH.
6 Jan 2012 (1 hour, total time to date: 78.5 hours)
Made minor adjustments and fabricated the tail wheel attach fitting doubler (and spare) for FS182.
13 Jan 2012 (1.5 hours, total time to date: 80 hours)
Laid-out and drilled attachment holes in the FS182 4340 steel tail wheel attach fitting.
14 Jan 2012 (2 hours, total time to date: 82 hours)
Aligned the BH182 tail wheel fitting on the BH and match drilled the attachment pilot holes in the BH
15 Jan 2012 (1 hour, total time to date: 83 hours)
Match drilled the attachment holes in the BH doubler for FS182
16 Jan 2012 (2 hours, total time to date: 85 hours)
Started work to mount the tail cone bulkheads on the building jig using 1x2 furring strips across the horizontal reference line (of each BH) to attach to the vertical support for BHs 177.5, 160, and 128.
17 Jan 2012 (1.5 hours, total time to date: 86.5 hours)
Began work to attach the 0.125x1x1 wing rear spar carry-through angle and 0.125 BH doublers (2024-T3) to BH99.35 – laid out the fastener locations.
18 Jan 2012 (1 hour, total time to date: 87.5 hours)
Fabricated a drilling guide using scrap 0.125 material to locate & match drill the pilot holes in the carry through angle.
19 Jan 2012 (1.5 hours, total time to date: 89 hours)
Drilled pilot holes in the carry through angle (all holes including the rear wing spar attach holes).
20 Jan 2012 (1 hour, total time to date: 90 hours)
Drilled pilot holes for the fasteners in the 0.125 BH99.35 bend line reinforcement doublers.
21 Jan 2012 (3 hours, total time to date: 93 hours)
Positioned the rear carry through angle on BH99.35 and drilled #30 holes to attach to the BH, clamped the reinforcements to the front of the BH, and drilled #30 holes along that portion of the rear spar carry through.
22 Jan 2012 (3 hours, total time to date: 96 hours)
Drilled pilot holes for the remaining attach holes in the BH99.35 reinforcement doublers, re-attached to the BH/carry through (with carry through doubler), & drilled #30 holes to attach to the BH.
23 Jan 2012 (1.5 hours, total time to date: 97.5 hours)
Drilled 3/16 hole (undersized) in the rear carry through angle for the rear wing spar attachments & did a test fit of BH 99.35 in the tail cone jig (forward facing flanges interfered with the vertical wooden jig supports). This was not noted in the drawings or construction procedures. If I had known this when I was building the tail cone jig, I would have increased the spacing of the vertical supports for BH99.35 from 22 to 25 inches & attached 1x2 blocks at the carry through attachment locations to create the required 22 inch fastener spacing. This would have allowed sufficient space for the portion of the BH that had the interference problem.
27 Jan 2012 (3 hours, total time to date: 100.5 hours)
Fabricated 2 (0.125x2x2) 6061 aluminum angles to support the wooden vertical jig supports to allow a portion of the supports to be removed with a router and permit the BH to fit in the jig.
28 Jan 2012 (2.5 hours, total time to date: 103 hours)
Aligned BH99.35 in the jig & drilled the rear spar attach holes in the vertical jig supports.
29 Jan 2012 (3 hours, total time to date: 106 hours)
Began work to align & attach all tail cone BHs in the jig. Starting with BH177.5. Also installed horizontal center line wire in the jig. A center line hole (I used a #41 bit) was required in BH177.5 for the alignment wire. Since this BH is used as the rear most reference for the tail cone BH alignment, much care was taken to help ensure the position was as accurate as possible. The bulkhead was clamped into position and checked/adjusted multiple times.
30 Jan 2012 (1.5 hours, total time to date: 107.5 hours)
Finished alignment & drilled attachment holes for screws to attach BH177.5 to the jig. A hole was drilled along the center line of the tail wheel fitting (as indicated in the plans), but I don't plan to use it as a rivet location for the fitting since it would prevent removal of the tail wheel bolt. I also drilled 2 #40 holes between the fitting and the reinforcing plate on each side of the BH. Finally, I used the top BH jig hole (with a small piece of 0.032 scrap as a large washer) to hole the BH flat against the jig.
31 Jan 2012 (1.5 hours, total time to date: 109 hours)
Began work to align & attach BH160.
1 Feb 2012 (2 hours, total time to date: 111 hours)
Added wooden stand-off for the upper attachment for BH160 and drilled attach holes. The BH was positioned slightly aft of the estimated final position since spacers will be used to make final adjustments for the final tail cone skin fit-up.
2 Feb 2012 (2 hours, total time to date: 113 hours)
Began work to align & attach BH182. Fabricated a wooden support to fit inside the steel tail wheel attach fitting and mount to the jig. This was a bit complicated since there is a "step" in the steel fitting at the lower fin spar attach point. I aligned this hole with the existing lower BH jig hole. The interesting thing to note is that the vertical distance between the lower and upper (2) fin spar attachment holes is 7.375 in. The BH height (as delivered) was about 0.19 inches longer than needed to provide the proper fit for the transverse BH flange with nut plates (if positioned flush to the A/C center line). Some additional adjustments may be required.
3 Feb 2012 (2 hours, total time to date:115 hours)
Attached the support for BH 182 to the jig & began work to align & attach BH128.
4 Feb 2012 (4 hours, total time to date: 119 hours)
Continued work to align BH128. Added 0.125 thick Masonite panel to help stabilize and flatten the BH. Additional 0.375 holes were drilled along the bulkhead web (used the same edge spacing as the existing jig holes) to attach the Masonite. In addition, 2 - 1x2 furring strips (approx. 6.5 in. long) were trimmed to fit and included along each side of the BH webs.
5 Feb 2012 (3 hours, total time to date: 122 hours)
Bad news! Discovered some alignment issues. BH128 needs to be moved slightly higher in the jig than indicated by the center line & needs to be moved forward. It turned out that I had wrongly assumed that the jig holes were always aligned to the aircraft center line. This was posted in the MM1 group on Yahoo, but I didn't catch it. I removed the 1x2 lateral BH support along with the Masonite and wood doublers, laid out the BH over the full scale drawing, and carefully determined the actual center line position. Then, I re-fabricated a new lateral support with the required offset to match the existing jig holes.
6 Feb 2012 (3 hours, total time to date: 125 hours)
Fabricated Masonite & wood spacers to allow the intermediate BHs (160 & 128) to be repositioned. Moved both BHs forward to line up along the top edge of the tail cone. Discovered that the bottom edges did not line up & will require additional adjustment. Also discovered that the rear spar carry through was not quite perpendicular to the center line. I should have caught this earlier, but better late than never.......
7 Feb 2012 (4 hours, total time to date: 129 hours)
Began work to re-align the jig to square-up the rear spar carry through angle in all 3 planes on BH99.35 using a laser level, spirit level, carpenters square, plumb bobs, as well as every other measuring device and geometric trick I could muster. I started and stopped several times to check and re-check, and the time estimate may be a little short. However, 4 hours would probably be about right for what it really took. Any extra was due to my slight OCD tendencies. ;-) In the end, only a slight adjustment was required to reposition the left upper alignment support for BH99.35.
8 Feb 2012 (2 hours, total time to date: 131 hours)
Double Checked alignment with a carpenter’s square mounted along the rear spar and checked the center line using 2 plumb bobs. Just in case, the time spent yesterday wasn't quite enough....
9 Feb 2012 (2 hours, total time to date: 133 hours)
Removed BH160&128 from the jig to make adjustments to the mounting attachments to properly space these BHs. Began work to re-do the jig attachments.
10 Feb 2012 (3 hours, total time to date: 136 hours)
Continued work on the jig attachment issue. The center line of BH160 required a minor offset adjustment and additional lateral support.
11 Feb 2012 (4 hours, total time to date: 140 hours)
Trial & error fitting process to position BH160 to align top, bottom, and sides with BH177.5 & 99.35. Began work to align BH128 & fabricated additional jig supports to hold BH128 flat.
12 Feb 2012 (3 hours, total time to date: 143 hours)
Bulkhead alignment finished! Checked and double checked the alignment from BH182 to BH99.35. This is extremely important since the skin must wrap around the BHs. The skin will not fit properly unless the edges of all of the tail cone BHs are in alignment.
13 Feb 2012 (1.5 hours, total time to date: 144.5 hours)
Added 0.032 spacers behind BH182 to account for the BH doubler at the tail wheel fitting. Also, rechecked the vertical alignment of BH182.
15 Feb 2012 (2 hours, total time to date: 146.5 hours)
Visit from Don Hayes (AP514-32-2163) to look at the project. He said that everything looks good to date & provided a few tips for fitting the belly skin. Started work to fit the belly skin – cut slots for the rear spar carry through.
16 Feb 2012 (1 hour, total time to date: 147.5 hours)
Trimmed the forward end of the skin to square wrt the center line. The belly skin supplied in the kit is over sized as expected, but it was not square to the center line. Since space in the jig is limited forward of BH99.35, it was necessary to trim this edge prior to fitting the skin.
17 Feb 2012 (1.5 hours, total time to date: 149 hours)
Started work to fit the tail cone belly skin to the BHs. Measured and marked the skin center line & drilled pilot holes to center the skin on BH99.35.
18 Feb 2012 (2 hours, total time to date: 151 hours)
Located the position of the tail wheel support bracket for BH177.5 & machined the skin cut-out. Drilled the corners of the cut out (3/16 bit) and used a Dremel cut off wheel to cut the edges. Filed and sanded the edges.
19 Feb 2012 (4 hours, total time to date: 155 hours)
Located position of the tail wheel support bracket for BH182 & machined the skin cut-out (using a 0.625 hole cutter). Discovered that BH182 flange tabs were too high & began work to adjust the BH alignment & height. Although the alignment looked fine when checked a string and straight edge, the tabs have square corners with a tight radius. After making the adjustments, the ~0.19 inch issue mentioned on 2 Feb turned out to be what was needed to fix the problem. I shortened the BH and moved it up (down in the jig) the required amount so that the center line was flush with the top of the BH and the flange tabs fit the belly skin.
20 Feb 2012 (4 hours, total time to date: 159 hours)
Finished adjustments and replaced BH182 in the jig. Resumed work to fit the belly skin to BH128. Cargo straps were required to pull the skin to fit tightly around the BH form.
21 Feb 2012 (3 hours, total time to date: 162 hours)
Cut slots in BH99.35 & 128 to accommodate the belly skin flanges, continued to drill #41 pilot holes (using a 12 inch bit) from the inside out for skin attachment on BH128 & 160. The 12 inch bit was used because it could be bent (like a snake bit) to clear the inner stiffening flanges of the BHs.
22 Feb 2012 (4 hours, total time to date: 166)
Cut slots in BH160 for the belly skin flanges, & drilled an attachment hole in the C/L of the tail wheel attach bracket on BH177.5 to permit better attachment to the jig (once belly skin flange slots are cut, the BH will not hold vertical alignment in the jig). Drilled #50 pilot holes in BH177.5 flange for belly skin attachment & began drilling #41 skin attach pilot holes from the inside.
23 Feb 2012 (2 hours, total time to date: 168)
Cut slots in BH177.5 for the belly skin flanges & notched the jig supports as needed. Began work to fabricate a dimpling bar (per Mustang Aero) from steel bar stock obtained from Phillips Sheet Metal, Dayton, OH.
24 Feb 2012 (2 hours, total time to date: 170)
Cut slots in BH182 for the belly skin flanges, and continued drilling skin attach pilot holes, & countersunk the dimpling bar tool for -4 flush rivets.
25 Feb 2012 (2 hours, total time to date: 172)
Drilled belly skin attach pilot holes for BH177.5. Since the jig prevents drilling the BH177.5 doubler flange from the inside, I made a template to locate the flange from the outside.
26 Feb 2012 (4 hours, total time to date: 176)
Drilled the BH177.5 doubler belly skin attach hole at the C/L, but decided to hold off on the other doubler holes until the doubler has been riveted to the bulkhead (the spacing may change slightly). Dressed the belly skin flange notches, marked & trimmed the belly skin flush to BH182 flanges (to facilitate drilling attach holes from the inside). Drilled #41 pilot holes for the belly skin at BH182.
27 Feb 2012 (1.5 hours, total time to date: 177.5)
Measured & marked tail cone BH flange notches for the left hand tail cone skin. Plans call for 0.5 in. overlay on the top, but that will leave no room for error for the fastener edge distance for the right hand skin attachment since it can’t extend past the C/L (it would create a longitudinal gap in the joint).
28 Feb 2012 (2 hours, total time to date: 179.5)
Started work to fabricate a “bending fixture” to pre-bend the left tail cone skin near the crown area. Traced and cut 0.75 thick wooden forms to match the 4 BHs along the crown line.
Note: This is not a recommendation, nor an official modification – only indication of what the builder did.
29 Feb 2012 (2.5 hours, total time to date: 182)
Aligned and attached wood formers to a 1x4x8ft board & sanded the edge to match the crown curvature along the length.
1 Mar 2012 (1.5 hours, total time to date: 183.5)
Attempted to pre-bend the left skin. Some effect was seen at the tail end, but was fairly minor. The wooden form for BH160 pulled out of the 1x4 during the process, so this effort was aborted.
2 Mar 2012 (1.5 hours, total time to date: 185)
Cut & filed the crown line notches in the tail cone BHs for the left skin flange.
3 Mar 2012 (2 hours, total time to date: 187)
A fixture to hold the left skin along the side of the tail cone jig was fabricated by hanging a finished 1x2 from the ceiling and clamping the skin to the board along the long edge. The “fixture” was adjusted to align & hold the skin to begin fit-up to the tail cone.
4 Mar 2012 (3 hours, total time to date: 190)
Another finished 1x2 was used to support the left tail cone skin flange and help to hold it tangent to the curve in the BHs. C-clamps were used to hold the board in place along the flange. Small wedges were cut to provide the proper angle between the board and vertical jig supports.
5 Mar 2012 (1.5 hours, total time to date: 191.5)
Began work attaching the left skin to the BHs. Started with the holes (#41) along the left skin flange (along the tail cone crown line).
6 Mar 2012 (2 hours, total time to date: 193.5)
Removed the 1x2 support along the flange line to drill 0.375 over sized holes in the wood to accommodate M3 machine screw heads to be used to securely hold the skin while being bent around the BHs. Installed the M3 screws, & replaced the 1x2 support.
7 Mar 2012 (2 hours, total time to date: 195.5)
Glued 2 finished 1x2s together to form a straight & stiff board to hold the left skin to the BHs using 3 cargo straps. Lined up the board and straps on the tail cone jig.
8 Mar 2012 (1.5 hours, total time to date: 197)
Resumed drilling #41 pilot holes along each BH flange. Used clecos except in two locations (aft BHs) were the bending force was highest (drilled #31 holes & used M3s at these 2 locations).
9 Mar 2012 (1.5 hours, total time to date: 198.5)
Continued drilling the left skin attachment holes around the BHs.
10 Mar 2012 (1 hour, total time to date: 199.5)
Continued attaching the left skin to the BHs.
11 Mar 2012 (2 hours, total time to date: 201.5)
Finished attaching the left skin to the tail cone BHs – including the BH attachment points where the left skin overlaps the belly skin.
12 Mar 2012 (1.5 hours, total time to date: 203)
Fabricated a skin seam drilling guides using 2 inch wide strips of 0.032 aluminum sheet. Drilled #41 holes with 1 in spacing using a drilling fence on a bench top drill (to ensure alignment). Fabricated 2 guides (26 and 36 long) to accommodate the exact spacing required between each tail cone BH.
13 Mar 2012 (2.5 hours, total time to date: 205.5)
Marked the skin seam line on the left side tail cone skin (~0.375 from belly skin flange), positioned the drilling guides, & drilled seam attachment pilot holes (#41). Used 1x2 wood strip and cargo straps to secure the guides and hold the skins together.
14 Mar 2012 (4 hours, total time to date: 209.5)
Removed the left tail cone skin for trimming. Trimmed the skin to nearly final size (left ~0.5 inches above the transverse BH & ~0.063 along the other edges for final finishing). Re-installed the left skin to re-check the fit.
21 Mar 2012 (3 hours, total time to date: 212.5)
Removed the left side skin & laid out the left and right skin flat in preparation to match drill the four upper BH flange attach holes in the right skin (at the upper flange). Match drilled the four holes & clecoed the skins in position in preparation to drill #41 skin seam pilot holes with 1 inch spacing along the upper flange (along the tail cone crown line).
22 Mar 2012 (1.5 hours, total time to date: 214)
Started work to drill #41 pilot holes along the left/right skin seam at the tail cone crown line. Rivet spacing is approx. 1 inch. Skins were laid out flat to facilitate drilling a straight seam line. Pilot holes were competed between BH177.5 & BH160.
23 Mar 2012 (2 hours, total time to date: 216)
Continued drilling skin seam pilot holes between BH160 & BH128.
24 Mar 2012 (2 hours, total time to date: 218)
Finished drilling skin seam pilot holes along the tail cone crown line.
25 Mar 2012 (2 hours, total time to date: 220)
The construction procedures call for the vertical supports at BH128 & BH 160 to be removed after the bottom and left skins are attached to facilitate the installation of the right skin. While this is necessary, since these supports interfere with the right tail cone skin, the vertical support for BH177.5 is also in the way. Therefore, I started work to add a vertical support behind BH182. The support will be attached to BH182 along the C/L of the 2x2 using the existing 3/16 bolt holes in BH182.
29 Mar 2012 (1 hour, total time to date: 221)
Re-checked the vertical alignment of the new BH182 vertical support (with the bottom & left skin in place). Cut and attached a second horizontal 1x2 to secure the vertical support to the jig. The tail cone skins were removed to allow access to BH182 so that the new vertical support could be attached to BH182. The new vertical support behind BH182 was not attached to the jig at this point.
30 Mar 2012 (3 hours, total time to date: 224)
Replaced the bottom and left skins with clecos to hold the tail cone in place. Added a 1x2 attachment block to the base of the new vertical support and the tail cone jig, fabricated a wooden shim required to fit the vertical support to the other existing horizontal support, & completed the temporary attachment of the new vertical support.
31 Mar 2012 (3 hours, total time to date: 227)
Removed the tail cone skins again (as well as the new vertical support behind BH182) so that the existing attachment between BH182 and BH177.5 could be removed in preparation for the removal of the BH177.5 vertical support. Replaced the new vertical support behind BH182 as well as the bottom and left tail cone skins. Cut & removed the vertical support for BH177.5. Removed the vertical supports for BH160 & BH128. The new vertical support now holds the aft end of the tail cone in place, and the jig is clear for the installation of the right tail cone skin.
1 Apr 2012 (4 hours, total time to date: 231)
Began work to fit the right tail cone skin. A 2nd 1x2 was hung from the ceiling to hold the lower edge of the right skin while attaching the upper (crown line) edge to the left skin. The left skin had to be “unwrapped” to relieve the bending loads along the crown line. Removed the M3 machine screws along the upper crown line for the left skin & connected the right skin to the left skin along the crown line (using -3 and -4 clecos as needed). Temporarily re-attached the left skin to the tail cone BHs.
5 Apr 2012 (1 hour, total time to date: 232 hours)
Since the vertical support for BH177.5 had to be removed, a new support is needed to hold the BH perpendicular to the horizontal C/L. Started work to fabricate the support. Designed and cut out a plywood backer board for the bulkhead.
6 Apr 2012 (1 hour, total time to date: 233 hours)
Cut and glued a 0.25 in. plywood doubler to the 0.75 in. backer board. This allows the use of a 2x4 to attach the backer board to the new vertical support (4.5 in. distance between BH177.5 & BH182). The 2x4 was finished on the disc sander to obtain a square edge and allow for some room for alignment.
7 Apr 2012 (2 hours, total time to date: 235 hours)
Cut and drilled pilot holes in 2, 1x2s to be used to attach the backing board to the 2x4. Aligned & glued the 1x2s to the backing board. The left skin flange notch was also cut and finished. Final alignment will take some time. I want to do all I can to keep BH177.5 square to the C/L (especially along the lateral axis) since the stabilizer spar will bolt to this BH.
Again, this is what I wish I'd done with the jig from the start, but didn't see it coming. Nothing in the drawings or construction procedures about the conflict with the vertical support for BH177.5 (per plans) and the right tail cone skin.
On a positive note, it will help Sean when he decides to build his MM.
Again, this is what I wish I'd done with the jig from the start, but didn't see it coming. Nothing in the drawings or construction procedures about the conflict with the vertical support for BH177.5 (per plans) and the right tail cone skin.
On a positive note, it will help Sean when he decides to build his MM.
8 Apr 2012 (Easter!) (5 hours, total time to date: 240 hours)
Screwed the 1x2s to the backing board. Fabricated a 0.25 in. plywood form to sandwich BH177.5 and hold it flush against the backing board. Match drilled the plywood to attach through the existing rudder cable & elevator horn holes in BH177.5. Aligned and attached the form and backing board around BH177.5. Aligned & attached the backing board to the new vertical support. Now, I'm finally ready to get back to work to fit the right hand tail cone skin. This has been a hour hour delay - plus a lot of time thinking this over.
Here is a view from the left side of the tail cone (note: it is still up side down in the jig) This skin will have to be opened from the seam line at the bottom skin flange to allow access to the inside for drilling out the #41 pilot holes for the right skin attachment. The upper radius is very tight, so more thought will go into how to proceed.
9 Apr 2012 (2 hours, total time to date: 242 hours)
I decided to employ 2 strategies to form the right skin around the BHs. Cargo straps would only be useful to help tighten up the skin/BH interface, but would have to be removed to allow access to the inside (to drill out the pilot holes through the BHs). The left skin flange is pulling away from the BH and pushing the right skin out as well - especially toward the aft end of the tail cone where the radii get smaller. It seems as though it would be helpful to fabricate a means to push the skins back toward the BHs.
Today, I cut 2x4s to attach to the bottom of the tail cone jig vertically (below the crown line) and run the 3.5 in. side laterally across the crown line. The 2x4s were notched to allow them to wrap around the vertical 2x6 at the base of the jig and just touch the floor to minimize any flexing of the jig when pressure is applied to the crown line. These 2x4s were attached at the locations of BH177.5 and BH 160 (where the bends are tightest). I also fabricated a wedge that will fit between the top of the 2x4 and the crown line. The wedge will be the means by which pressure can be applied to the skin. A number of these will be required to hole the skin on both sides of the crown line.
Today, I cut 2x4s to attach to the bottom of the tail cone jig vertically (below the crown line) and run the 3.5 in. side laterally across the crown line. The 2x4s were notched to allow them to wrap around the vertical 2x6 at the base of the jig and just touch the floor to minimize any flexing of the jig when pressure is applied to the crown line. These 2x4s were attached at the locations of BH177.5 and BH 160 (where the bends are tightest). I also fabricated a wedge that will fit between the top of the 2x4 and the crown line. The wedge will be the means by which pressure can be applied to the skin. A number of these will be required to hole the skin on both sides of the crown line.
10 Apr 2012 (1 hour, total time to date: 243 hours)
Cut 3 additional wedges to be used to secure the skin along the crown line edge of the tail cone. Test fit the wedges, and glued another set of finished 1x2s together to be used to hold the right side skin along the BH line. Also, temporarily attached a 1x2 between the rear vertical support and the aft jig alignment support as an anchor for the aft end of the 2x2 as it is used to support the right tail cone skin.
11 Apr 2012 (4.5 hours, total time to date: 247.5 hours)
After much preparation and a few delays, I started work to fit the right tail cone skin. Cargo straps (4) were wrapped around the tail cone at each full BH location, and 2, 2x2s were inserted between the straps and the right hand skin. As the straps were tightened, the 2x2s were positioned to hold the skin against the BHs (starting nearest to the crown line). Some trimming of the skin was required at BH99.35 to clear the vertical support. Once the skin was in position, the 2x2s were clamped to the tail cone at each end. At this point, the aft end of the skin had to be trimmed to allow space for the clamps. The straps were removed, and the left skin was opened along the bottom skin flange line far enough to reach in with an air drill (using a 12 in. #41 bit). The pilot holes were drilled from the inside, starting nearest to the crown line at BH177.5 working forward toward BH99.35. The 2x2s had to be adjusted to assure a good fit to the BHs. The first row of pilot holes were drilled and clecoed. To be sure that the skin was completely tight around the lower edge of BH99.35, the left side was closed, and straps were replaced. Once the skin was tight, pilot holes were drilled in the BH99.35 flange to approximately 4.5 inches from the crown line (4 pilot holes were drilled and clecoed in the BH99.35 flange).
My idea about the use of wedges to press the skin against the BH from the bottom didn't help much at all. The 2x2s and cargo straps were good enough. I did use one 3/8 plywood wedge at BH177.5 to help hold the right skin (on the left side of the crown seam) since it really opens up because of the tight bend, and I thought it wouldn't be a bad idea to relieve some of the load and I hope it helps to put at least a little permanent bend in the area. In the end, I don't want to have a gap in the seam line because the skins are highly pre-loaded due to the tight radius. I will probably need to roll the edges after trimming to the final edge distance.
My idea about the use of wedges to press the skin against the BH from the bottom didn't help much at all. The 2x2s and cargo straps were good enough. I did use one 3/8 plywood wedge at BH177.5 to help hold the right skin (on the left side of the crown seam) since it really opens up because of the tight bend, and I thought it wouldn't be a bad idea to relieve some of the load and I hope it helps to put at least a little permanent bend in the area. In the end, I don't want to have a gap in the seam line because the skins are highly pre-loaded due to the tight radius. I will probably need to roll the edges after trimming to the final edge distance.
12 Apr 2012 (1.5 hours, total time to date: 249 hours)
Continued drilling pilot holes from the inside to fit the right tail cone skin. Completed two more rows of holes moving up from the crown line. The clamps attaching the 2x2s to the forward end of the RHS of the tail cone tend to push BH99.35 aft. I have been making it a habit to check the alignment of this BH before drilling any pilot holes to fit the right skin. The left skin was closed, cargo straps replaced, tightened, and BH99.35 was measured and moved to be in proper alignment. Three additional pilot holes were then drilled in BH99.35 moving away from the crown line. Finally, I discovered that I had neglected to drill some of the #50 pilot holes in the right side of the BH177.5 flange, so the right skin will have to be opened up to allow these to be drilled in the proper locations before resuming the right tail cone skin fitting process.
As Roseanne Roseanna Danna used to say: "It's always sumpthun"
As Roseanne Roseanna Danna used to say: "It's always sumpthun"
13 Apr 2012 (4 hours, total time to date: 253 hours)
Made some very good progress today. Opened up the right side again to drill the pilot holes I missed in BH177.5. Closed it back up and resumed drilling the right side attachment holes along the BHs. As shown in the picture, the holes in the internal BHs have to be drilled from the inside, so the left side was partially unbuttoned to allow access. As noted earlier, 2x2s (~90 inches long) were clamped at each end along the right side to hold the skin against the BHs. In some cases, Masonite shims were inserted to make better contact. Worked my way up from the crown line 2 rows at a time, closed the left side, used cargo straps to snug the skin evenly, checked the alignment of BH99.35, and drilled more attachment pilot holes in that BH (again, those holes are accessible from the outside). Repeated this pattern until reaching the bottom skin flange line.
It seemed like pretty slow going, but it feels great to this behind me. Tomorrow, I will drill the attachment holes at the bottom/right side seam line. It may be necessary to unbutton the bottom skin along the left side seam to be able to reach the holes at the BHs. However, the rest of the pilot holes can be drilled from the outside.
It seemed like pretty slow going, but it feels great to this behind me. Tomorrow, I will drill the attachment holes at the bottom/right side seam line. It may be necessary to unbutton the bottom skin along the left side seam to be able to reach the holes at the BHs. However, the rest of the pilot holes can be drilled from the outside.
14 Apr 2012 (3.5 hours, total time to date: 256.5)
Drilled attachment pilot holes at the BHs along the bottom/right side seam. The holes at BH177.5, 160, & 128 were drilled from the inside (as shown). The holes at BH182 and BH99.35 (each end of the tail cone) required the use of a hole finder (strap duplicator) since the jig obstructed direct access.
Started work to drill the bottom/right skin seam line. Laid out the rivet line, closed the tail cone with cargo straps/1x2 above the line, and completed the holes between BH177.5 & BH160.
Started work to drill the bottom/right skin seam line. Laid out the rivet line, closed the tail cone with cargo straps/1x2 above the line, and completed the holes between BH177.5 & BH160.
Hole Finder (Strap Duplicator)
This was the first time I've used this tool, and I must say that it works like a charm! I'm sure I'll have many more opportunities to make use of it as the project continues. This tool should be in your toolbox if you are doing any sheet metal work.
Looking Happy
I'm looking happy because I'm nearly finished fitting the tail cone. A lot more work to go, but the tail cone has been full of surprises.
Rob Reuter came over this morning for some riveting practice and took this picture.
Rob Reuter came over this morning for some riveting practice and took this picture.
15 Apr 2012 (2.5 hours, total time to date: 259 hours)
Finished drilling the bottom/right side skin seam line. I think it turned out well, and it feels great to have this part of the project finished. I'll need to remove the skins for trimming/deburring, then re-install to check the fit, and start reaming the holes out in preparation for dimpling.
16 Apr 2012 (3.5 hours, total time to date: 262.5 hours)
Removed the right tail cone skin from the jig. Trimmed & finished all of the edges to final dimensions except for the crown seam edge (simply ran out of time). Also, drilled two pilot holes in the right side of the flange in BH182. I had planned on drilling those from the inside edge, but the new rear vertical support is in the way. I will drill through the skin using the trusty hole finder after I put the skin back on the tail cone.
17 Apr 2012 (2 hours, total time to date: 264.5 hours)
Trimmed and finished the crown seam edge of the right tail cone skin. Rolled the aft end of the crown seam of the skin using a broom stick and duct tape to facilitate the fit around the rear BHs. I used large adjustable pliers to twist the broom stick to provide the force required to pre-bend the aft crown seam area. The bend should help the overall fit. I will need to do the same to the left skin. Re-attached the right skin to the tail cone and drilled the 2 attachment pilot holes at BH182. Removed the left tail cone skin for final trimming & finishing.
18 April 2012 (2.5 hours, total time to date: 267 hours)
Trimmed and finished all of the edges of the left tail cone skin. Also rolled the aft end of the left skin using the same technique as I used on the right skin. This time I tried a larger (1.25 in. dia.) wooden push broom handle. It seemed to work better - probably because I could apply more torque with the long adjustable pliers.
Partially installed the left skin on the tail cone along the bottom/right skin seam line and did a quick check of the fit around the crown line. It looked much better with the rolled edge. I will remove the right skin and re-roll it with the larger handle.
Partially installed the left skin on the tail cone along the bottom/right skin seam line and did a quick check of the fit around the crown line. It looked much better with the rolled edge. I will remove the right skin and re-roll it with the larger handle.
19 Apr 2012 (0.5 hours, total time to date: 267.5 hours)
Re-rolled the aft crown seam line of the right tail cone skin & did minor finishing work on the edges.
20 Apr 2012 (1.5 hours, total time to date: 269 hours)
Re-attached the left and right tail cone skins to the BHs. I found that the best way to do this is from the crown seam line. The skins are laid out on each side of the crown line using the 1x2 supports that are hung from the ceiling (see the photo from 1 Apr). I used 2 cargo straps to wrap the skins around the BHs.
As shown in the photo, the edge rolling made a big difference in the crown line fit. Compare this to the similar photo taken on 12 April. The areas that appear to be darker are areas where the protective white vinyl sheet was pulled from the aluminum when I removed the duct tape after rolling the edges.
As shown in the photo, the edge rolling made a big difference in the crown line fit. Compare this to the similar photo taken on 12 April. The areas that appear to be darker are areas where the protective white vinyl sheet was pulled from the aluminum when I removed the duct tape after rolling the edges.
Here's a picture of the inside of the tail cone looking aft (it is still up side down in the jig). The Masonite and plywood supports are still in place to stabilize BH177.5 (background) & BH128 (foreground).
21 Apr 2012 (2 hours, total time to date: 271 hours)
Opened the bottom skin seam line, and removed the bottom skin to locate the skin attachment points for the BH177.5 and BH182 tail wheel fitting doublers. Replaced the bottom skin & drilled the #41 BH doubler attachment pilot holes at BH177.5. Since the BH182 doubler is accessible with the hole duplicator, I removed the bottom skin again, and drilled the #41 attachment holes in that doubler, replaced the bottom skin again, and drilled the holes on the left side of the bottom skin. Ran out of time due to an upcoming trip, but will resume work when I return (26 April).
26 Apr 2012 (2 hours, total, time to date: 273 hours)
Finished drilling the two remaining BH182 doubler attachment holes on the right side of the tail cone (using the hole finder). Began re-drilling all of the skin/BH attachment holes out to 0.125 inch in preparation for dimpling and riveting. The holes were purposely undersized (instead of using #30) to allow for some hole expansion during dimpling. The #31 hole was not large enough for the dimple die mandrel.
The only difference in this photo is the color of the clecos :-) However, this moves me a step closer to finally riveting the tail cone in place. I will need to add at least one access panel to the aft end since it will be necessary to reach inside the aft tail cone to attach the stab and fin root ribs and the tail wheel attach bolt. Also, it will be needed for aircraft maintenance.
The only difference in this photo is the color of the clecos :-) However, this moves me a step closer to finally riveting the tail cone in place. I will need to add at least one access panel to the aft end since it will be necessary to reach inside the aft tail cone to attach the stab and fin root ribs and the tail wheel attach bolt. Also, it will be needed for aircraft maintenance.
27 Apr 2012 (2 hours, total time to date: 275 hours)
Continued drilling out the skin/BH attachment holes to 0.125 in. diameter. Finished all holes except the crown seam line.
28 Apr 2012 (3 hours, total time to date: 278 hours)
Drilled out the crown seam line to 0.125 in. Removed the bottom skin, trimmed and finished the forward and aft ends to the final dimensions.
Measured the approximate location of the stabilizer root attach bolts at BH160 in preparation for locating the left skin access panel. As there are no instructions for this panel (one size doesn't necessarily fit all), I will design the panel, and double check the position and layout.
The access panel must allow for installation & maintenance of the tail wheel attach bolt, the stabilizer & fin attach bolts, and may be useful to provide access for a bore scope to inspect the inside of the closed area of the tail cone (between BH177.5 & BH 182.
Measured the approximate location of the stabilizer root attach bolts at BH160 in preparation for locating the left skin access panel. As there are no instructions for this panel (one size doesn't necessarily fit all), I will design the panel, and double check the position and layout.
The access panel must allow for installation & maintenance of the tail wheel attach bolt, the stabilizer & fin attach bolts, and may be useful to provide access for a bore scope to inspect the inside of the closed area of the tail cone (between BH177.5 & BH 182.
30 Apr 2012 (3 hours, total time to date: 281 hours)
I came up with a design for the access panel with an opening large enough for a grown man's arm to fit through it. Some access panels for the midget are attached between BH177.5 and BH160. However, I also spent time laying out the location of the stabilizer, and my design will not fit in that area. I don't have a clue how those guys use their panel, but all I know is that my arm would never fit. So, my panel will have to go just forward of BH160 and just about the bottom/left skin seam.
My time today was spent laying out the location of the stabilizer, determining where to put the panel, and starting to fabricate the panel doubler as shown in the picture. The attach rivet locations are only drawn in one quadrant of the image (no sense wasting more time). I will need to make two of them. One to use as a template to cut out the panel (it will be cut out so that the inside matches the size of the panel). The actual doubler will be match drilled from the template (it will include the overlap to attach the panel using nut plates as indicated in the image.
My time today was spent laying out the location of the stabilizer, determining where to put the panel, and starting to fabricate the panel doubler as shown in the picture. The attach rivet locations are only drawn in one quadrant of the image (no sense wasting more time). I will need to make two of them. One to use as a template to cut out the panel (it will be cut out so that the inside matches the size of the panel). The actual doubler will be match drilled from the template (it will include the overlap to attach the panel using nut plates as indicated in the image.
1 May 2012 (2 hours, total time to date: 283 hours)
Continuing the work on the tail cone access panel.
Thanks to some valuable input and advise from my good friend and FAA DER, Tom Deiters, I decided to add another row of -4 rivets to the 0.032 doubler. Tom directed me to a section in Michael Niu's Book "Airframe Structural Design," on ring doublers for round holes in shear webs (Section 6.3). Although this application is slightly different, the reference provides best practices for this type of doubler arrangement, and will be somewhat more conservative since the panel can take load.
I determined the approximate shear flow in the area of the panel based on the max gross weight, estimates of the stabilizer down load (based on the force required to balance the wing lift) & approx. weight of the tail section. At 10 G's and some added safety factor (2), the gross shear flow was estimated to be approx. 100 #/in. However, the lowest value shown for the ratio of doubler ring width to hole diameter is 0.35. For my average hole (in the skin) dia of 7 in., the ring width should be at least 2.45 in. The doubler thickness can be as low as the 0.025 thickness of the skin (due to the low gross shear flow), but a 0.032 doubler would be compatible with the thickness of the BHs, and would be less susceptible to damage during panel removal/replacement over the long term.
Thanks to some valuable input and advise from my good friend and FAA DER, Tom Deiters, I decided to add another row of -4 rivets to the 0.032 doubler. Tom directed me to a section in Michael Niu's Book "Airframe Structural Design," on ring doublers for round holes in shear webs (Section 6.3). Although this application is slightly different, the reference provides best practices for this type of doubler arrangement, and will be somewhat more conservative since the panel can take load.
I determined the approximate shear flow in the area of the panel based on the max gross weight, estimates of the stabilizer down load (based on the force required to balance the wing lift) & approx. weight of the tail section. At 10 G's and some added safety factor (2), the gross shear flow was estimated to be approx. 100 #/in. However, the lowest value shown for the ratio of doubler ring width to hole diameter is 0.35. For my average hole (in the skin) dia of 7 in., the ring width should be at least 2.45 in. The doubler thickness can be as low as the 0.025 thickness of the skin (due to the low gross shear flow), but a 0.032 doubler would be compatible with the thickness of the BHs, and would be less susceptible to damage during panel removal/replacement over the long term.
2 May 2012 (1.5 hours, total time to date: 284.5 hours)
Finished drilling the pilot holes in the access panel template.
The next task will be to match drill the holes in the doubler itself. The template will then be machined so the inside dimensions will match the access panel. The template will then be positioned and mounted on the tail cone so the panel may be cut out with a sharp awl. When finished, the template will be removed, and the doubler will be installed with the final inside dimensions to allow the panel to be secured with 10, 8x32 nut plates.
The next task will be to match drill the holes in the doubler itself. The template will then be machined so the inside dimensions will match the access panel. The template will then be positioned and mounted on the tail cone so the panel may be cut out with a sharp awl. When finished, the template will be removed, and the doubler will be installed with the final inside dimensions to allow the panel to be secured with 10, 8x32 nut plates.
3 May 2012 (1 hour, total time to date: 285.5 hours)
Match drilled the #41 pilot holes in the actual access panel doubler. Now, I have 2 matching panels (template & doubler). When finished, I'll hang on to the template to use as a drilling guide if I need another access panel of this size on the forward fuselage (or in case Sean wants to use it for his MM1).
4 May 2012 (0.5 hour, total time to date: 286 hours)
I laid out the cutting lines on the doubler template and drilled out (0.25 in.) the 4 holes that serve as the center of the 4 radial cuts for the inside dimension of the doubler. My fly cutter uses a 0.25 bit. Unfortunately, I had forgotten that my cutter has a max radius of 2 in., and I need a 2.875 inside radius for the template doubler. So, now is a good time to stop, and think twice before going forward.
5 May 2012 (3 hours, total time to date: 289 hours)
I decided to cut out the inside of the template with a dremel cut-off wheel, and use an air sander with a 0.75 in. drum sanding attachment to clean up the cut. After using the air sander, I also sanded the inside & outside edges by hand, and finished with a scotchbrite wheel and pad.
The template is now ready to install on the inside of the tail cone.
The template is now ready to install on the inside of the tail cone.
6 May 2012 (3.5 hours, total time to date: 292.5 hours)
Cut the inside of the access panel doubler using a fly cutter (since the 4 inside radii for the doubler are 2 in.). I had to get a little creative after the first cut since the center of the other 3 holes are inside the radius of the first cut. I mounted the panel on a 1x8 board, and drilled 0.25 pilot holes in the board at each of the 4 hole centers in the panel. I also had to re-use the material cut out of the first hole to provide a guide for the pilot drill since, without it, the cutter contacts the panel before the pilot bit is fully seated in the hole in the wood under the panel. I attached this material at each hole center using 2 wood screws placed inside the cutting radius. Once the cuts were finished, I trimmed the inside edges flat using an air powered die grinder with a sanding attachment, switched to hand sanding, and finally the die grinder again with a scotchbrite wheel. The outside of the panel was cut on a band saw, sanded on a disk sander, and finished with a scotchbrite wheel. In the photo, the template and panel are shown clecoed together.
Work was started on the second access panel to be placed under the stabilizer. The larger panel will have to be placed further from BH160 than originally planned, so I won't be able to reach all of the way back to the tail wheel attach bolt. However, this is probably for the best since it would be virtually impossible to see inside the tail cone with my arm in the single larger panel. The smaller panel was made as large as possible, but was limited by the position of the bottom skin flange and the stabilizer root rib. The panel opening is 3.5 inches with corner radii of 0.375 in. The template was cut to the final outside dimensions, and the pilot attachment holes were match drilled to a second sheet to be used at the panel doubler.
Work was started on the second access panel to be placed under the stabilizer. The larger panel will have to be placed further from BH160 than originally planned, so I won't be able to reach all of the way back to the tail wheel attach bolt. However, this is probably for the best since it would be virtually impossible to see inside the tail cone with my arm in the single larger panel. The smaller panel was made as large as possible, but was limited by the position of the bottom skin flange and the stabilizer root rib. The panel opening is 3.5 inches with corner radii of 0.375 in. The template was cut to the final outside dimensions, and the pilot attachment holes were match drilled to a second sheet to be used at the panel doubler.
7 May 2012 (1.5 hours, total time to date: 294 hours)
Cut and finished the inside dimensions of the smaller access panel template. The initial cuts were made using a fly-cutter for the corner radii and a dremel cut-off wheel to cut out the sides. The finishing work was done with a sanding disk on an air die grinder, some hand sanding, and finally a scotchbrite wheel. The access panel doubler itself was cut and finished in the same manner, except the corner radii were cut using a 0.75 dia. sheet metal hole cutter.
Now, both access panels have been fabricated and are ready to be installed on the tail cone.
Now, both access panels have been fabricated and are ready to be installed on the tail cone.
10 May 2012 (2 hours, total time to date: 296 hours)
Removed the bottom & left tail cone skins to allow easy access for installation of the tail cone access panels on the left skin. I positioned the smaller access panel slightly aft of the mid-point between BH160 & BH177.5. It was a close fit between the bottom skin flange & the stabilizer. By my measurements, there will be approx. 0.5+ inch clearance between the stabilizer the the access panel cover. The opening will be sufficient to get my hand inside and reach anywhere between the BHs.
I drilled 8 of the attachment holes around the template to secure it to the left skin with -3 clecos. I'll finish the rest tomorrow, then begin cutting out the panel using the inside edge of the template as a guide.
I drilled 8 of the attachment holes around the template to secure it to the left skin with -3 clecos. I'll finish the rest tomorrow, then begin cutting out the panel using the inside edge of the template as a guide.
11 May 2012 (1 hour, total time to date: 297 hours)
Drilled all 24 attachment pilot holes for the inner row of rivets for the aft access panel and began work to cut out the access panel door using an awl to make a clean, fine cut.
12 May 2012 (3 hours, total time to date: 300 hours)
Finished cutting out both access/inspection panel cut-outs in the left tail cone skin. It was slow going with the awl, but I think it was well worth it for the thinner cut line. After finishing the edges, it leaves a nice gap (not too much).
There was limited space available between the stabilizer and the bottom skin flange (essentially, the left tail cone stringer), so I cut the doubler a bit on the narrow side. After looking at it on the tail cone, I am considering whether to make a new doubler with a 3rd row of fasteners on each side and on the stabilizer side. The stringer limits the size of the doubler on that side, but the only other concern is the clearance of the removable panel (it will not change).
There was limited space available between the stabilizer and the bottom skin flange (essentially, the left tail cone stringer), so I cut the doubler a bit on the narrow side. After looking at it on the tail cone, I am considering whether to make a new doubler with a 3rd row of fasteners on each side and on the stabilizer side. The stringer limits the size of the doubler on that side, but the only other concern is the clearance of the removable panel (it will not change).
13 May 2012 (4 hours, total time to date: 304 hours)
Drilled out all of the attachment holes in the larger access/inspection panel to 0.125 in preparation for dimpling. I decided to replace/re-fabricate the original aft panel doubler and add a 3rd row of rivets on the top and sides. This will provide a better match in terms of doubler/skin replacement area. The shear flow in the tail cone is very low, so the rivet spacing is closer than required, but I wanted to create a logical pattern around the panel in the space available. The space along the bottom skin flange line did not permit an additional row of fasteners to be added.
14 May 2012 (3 hours, total time to date: 307 hours)
Drilled out the fastener holes in the smaller access/inspection panel to 0.125 for dimpling and trimmed the bottom edge of the doubler for clearance with the bottom skin flange.
Started work on a C-frame table to be used to dimple the skins on the airplane.
Started work on a C-frame table to be used to dimple the skins on the airplane.
17 May 2012
The C-Frame table is finished! Now, back to work on the airplane.........
18 May 2012 (2 hours, total time to date: 309 hours)
Used a broom handle, duct tape, & large adjustable pliers to add more curvature to the forward top edge of the RH tail cone skin. This attempt was marginally successful. More work will be needed before the tail cone skins are re-assembled.
Removed the Masonite reinforcement from BH 128 & removed the left tail cone skin from the BHs in preparation for final assembly. Removed all BHs except BH99.35 & BH182 from the tail cone jig (also in preparation for final assembly.
If not for the attachment holes, trimming, and access/inspection openings, it looks like I'm starting the project all over again. Hopefully, it won't be long before the tail cone is back together for the last time.
Removed the Masonite reinforcement from BH 128 & removed the left tail cone skin from the BHs in preparation for final assembly. Removed all BHs except BH99.35 & BH182 from the tail cone jig (also in preparation for final assembly.
If not for the attachment holes, trimming, and access/inspection openings, it looks like I'm starting the project all over again. Hopefully, it won't be long before the tail cone is back together for the last time.
19 May 2012 (3.5 hours, total time to date: 312.5 hours)
Drilled out the attachment holes to #30 for the doubler and tail wheel fitting in BH177.5. De-burred and finished (filed, sanded, and scotchbrite) the BH, and dimpled the tail cone skin attachment holes using a vice-grip plier dimpling tool.
De-greased, etched, and alodined BH177.5 and the doubler as shown in the photo.
De-greased, etched, and alodined BH177.5 and the doubler as shown in the photo.
20 May 2012 (4.5 hours, total time to date: 317 hours)
De-burred the attachment holes in both access panel doublers.
Prepared BH182 for final assembly as follows:
Drilled out the doubler/tail wheel fitting attachment holes to final size. The holes in the BH were drilled to 0.125 since they are dimpled, and the holes in the doubler & fitting were then drilled to #30 (they will not be dimpled). The tail wheel fitting attach holes in the back face of the doubler were C/S while clecoed to the fitting. This operation results in a knife-edge condition in the doubler (this is why it was done while attached to the fitting), but minimizes the C/S in the fitting itself. There are two other rivet holes connecting the doubler to the BH which are clear of the fin spar and will be riveted with universal head rivets. Then, the BH & doubler were de-burred and the edges were filed, sanded, and finished with Scotchbrite. The tail cone skin attachment holes in the flanges were dimpled using the vice-grip plier dimpler. The tail wheel fitting holes in the BH were dimpled using the C-frame dimpler. Finally, the BH and doubler were de-greased, etched, and alodined.
Prepared BH182 for final assembly as follows:
Drilled out the doubler/tail wheel fitting attachment holes to final size. The holes in the BH were drilled to 0.125 since they are dimpled, and the holes in the doubler & fitting were then drilled to #30 (they will not be dimpled). The tail wheel fitting attach holes in the back face of the doubler were C/S while clecoed to the fitting. This operation results in a knife-edge condition in the doubler (this is why it was done while attached to the fitting), but minimizes the C/S in the fitting itself. There are two other rivet holes connecting the doubler to the BH which are clear of the fin spar and will be riveted with universal head rivets. Then, the BH & doubler were de-burred and the edges were filed, sanded, and finished with Scotchbrite. The tail cone skin attachment holes in the flanges were dimpled using the vice-grip plier dimpler. The tail wheel fitting holes in the BH were dimpled using the C-frame dimpler. Finally, the BH and doubler were de-greased, etched, and alodined.
21 May 2012 (1.5 hours, total time to date: 318.5 hours)
Prepared BH160 for assembly. De-burred the attachment holes, filed, sanded, and finished with Scotchbrite. Dimpled the flange attachment holes. I will hold off on the alodine process until I have prepared BH128 and dimpled the access panel doublers, so I can do a larger batch at one time.
22 May 2012 (2 hours, total time to date: 320.5 hours)
Prepared BH128 for assembly. De-burred the attachment holes, filed, sanded, and finished with Scotchbrite. Dimpled the flange attachment holes. I'm getting more efficient at this task, but this BH is considerably larger than the last 3. :-)
23 May 2012 (2.5 hours, total time to date: 323 hours)
Drilled out the larger access panel cover attachment holes in the doubler and cover to #19 for the #8 machine screws that will attach the panel cover to the panel doubler. These holes will need to be dimpled for the #8 machine screws, but the nut plate attachment holes will need to be drilled first.
BH128 and BH160 were de-greased, etched, and alodined as indicated in the photo. This was more time consuming due to the larger size of the BHs.
BH128 and BH160 were de-greased, etched, and alodined as indicated in the photo. This was more time consuming due to the larger size of the BHs.
24 May 2012 (1 hour, total time to date: 324 hours)
Drilled the nut plate attachment holes for the lower fin spar bolt in the aft tail wheel attachment fitting (BH182). Now, BH182 & BH177.5 are ready to be riveted together to be followed by the re-assembly of the tail cone bottom and side skins.
26 May 2012 (3 hours, total time to date: 327 hours)
Riveted the tail wheel attachment fittings and doublers to BH182 & BH177.5 (also attached the nut plate on the fitting at BH182) with help from Rob Reuter. Rob did a better job with the bucking bar than I did, so I was relegated to being the driver :-) I used AC Tech AC-236 tank sealant between the layers and used it to wet the rivets prior to driving. The steel/aluminum interface is a corrosion concern.
Now, I can get ready to put the tail cone skin on the BHs.
Now, I can get ready to put the tail cone skin on the BHs.
28 May 2012 (3.5 hours, total time to date: 330.5 hours)
Began work to deburr & dimple the bottom tail cone skin. I used the C-frame dimpler to finish the attachment holes along the flanges. The rest will have to be done using a rivet gun as recommended by Mustang Aero.
29 May 2012 (2.5 hours, total time to date: 333.0 hours)
Continued work to deburr and dimple the tail cone bottom skin. Working around the BH attachment holes with the rivet gun/flush set was more challenging than expected. I practiced on some scrap material to set the air pressure correctly and to see how the method worked. The retaining spring left marks on the scrap, so I used some masking tape to cover the spring. It was very difficult to hold the steel bar tightly against the inside of the skin (mainly because of the curvature at the aft end). I had to drill out two rivets that became stuck in the hole(s). I then tried using the dimple die with even lower pressure (~25 psi), and held the female die by hand in the inside of the skin. This seemed to work better, but it is still very easy to leave marks at the edge of the die. I used a small (~1.5x1.5 in.) scrap of 0.75 thick wood to hold the female die in my hand (I drilled a 0.1875 hole in the edge of the wood to hold the die post). This seems to work the best, except in areas with a lot of curvature. I drilled and c/s another hole along a the convex curved edge of the steel bar and used it in place of the female die in those locations. Since the steel is heavier, it is even easier to leave marks in the skin. These can be buffed out for the most part, but low pressure is the key to keeping this to a minimum.
30 May 2012 (1.5 hours, total time to date: 334.5 hours)
Finished dimpling the bottom skin fastener holes. After using the "free style" dimpling method on the curved bottom skin surface, I learned a few more things that may also be helpful to anyone else planning to use this method. I initially thought the marks left at the edge of the die were caused by misalignment of the male die. After many attempts to improve my technique, I discovered that it was the female die that was the primary cause of the problem. The marks highlight any area that is in closer contact to the back side of the sheet. Therefore, it is most important to hold the female die (or steel plate) as evenly as possible on the back side. It is common to see a concentric ring around a dimple formed using the C-frame, but they are usually faint, and easily removed with a scotchbrite pad. Deeper "smile" marks are easy to create using the free style dimpling process. Holding the back plate (or female die) more evenly will improve the situation, but the right air pressure is also quite important (as I wrote yesterday). In my setup, ~25 psi worked well with a 3x rivet gun. I also have a regulator on the gun that I used to fine tune the final pressure. I lowered the pressure to the point where the gun could not form a dimple, then increased it to the lowest pressure that would form a dimple. That worked best for me.
I still spent some time buffing out marks on the surface.
Note, the picture below shows that I did not dimple any holes along the forward edge of the skin. This area will be overlapped by the forward fuselage skin, and I will do these holes after fitting the forward fuselage skin.
I still spent some time buffing out marks on the surface.
Note, the picture below shows that I did not dimple any holes along the forward edge of the skin. This area will be overlapped by the forward fuselage skin, and I will do these holes after fitting the forward fuselage skin.
31 May 2012 (3.5 hours, total time to date: 338.0 hours)
De-greased, etched, and alodined the bottom tail cone skin. I removed the protective plastic (except where the forward fuselage skin will overlap). It's extreemly difficult to get a nice even look on the skin with the alodine. The larger the part, the more difficult - this is very easy to see in this case. The good news is that it will be painted eventually. :-)
1 Jun 2012 (1.5 hours, total time to date: 339.5 hours)
Applied a light prime coat along the mating surfaces of the bottom skin and BHs. Also, primed the inside of the bottom skin area between BH177.5 & BH182. This area will have very limited accessibility once the tail cone is closed.
2 June 2012 (1 hour, total time to date: 340.5 hours)
Replaced the bottom tail cone skin on the jig and clecoed all of the BHs in place for riveting. Beth was not able to apply sufficient pressure to hold the rivet head against the skin. As a result, the first rivet was set with the head protruding from the skin. I drilled it out, and we tried it again. I finished setting the first rivet while Beth helped by looking to see if I had the flush head level on the skin. I was holding the bucking bar with my right hand, and the gun in my left. I set a second rivet in the same manner, and had good results. I created some minor scratches on the web of BH 128 with the bucking bar, and will buff them out later. I will add more protective tape to the bar and continue as far as possible tomorrow.
3 Jun 2012 (1 hour, total time to date: 341.5 hours)
I'm starting to get the "hang" of solo riveting. I set 11 rivets in the bottom skin along BH128. Eight more to go on that BH. Luckily, I can reach everything so far.
There's a bit of a "ripple" in the skin around the corner, but I can't imagine how it could be avoided. Maybe I shouldn't have used so many rivets in that area? The BH comes with pilot holes at the corners of each flange. The max rivet spacing for the skin/BH attachment is 2 inches. This is what I used along the flat bottom edge. The hole in the BH web (in the photo below) is at the C/L. Pilot holes were pre-drilled at corners of the tabs, but along the relatively flat surface, I used the holes at the 2 inch spacing. Otherwise, there would be a lot of unnecessary rivets. The shear flow is very low in the tail cone - back of the envelope conservative estimate is <100 lbs/in at 10 Gs. Because of the tighter radius around the corners, I opted for the closer spacing. In hindsight, perhaps I shouldn't have done it, but it's done now. The shop heads seem OK.
If anyone has any comment, please let me know. You always want things to look perfect, but it never works out quite that way in reality. I'll borrow the phrase: "Onward & Upward...."
There's a bit of a "ripple" in the skin around the corner, but I can't imagine how it could be avoided. Maybe I shouldn't have used so many rivets in that area? The BH comes with pilot holes at the corners of each flange. The max rivet spacing for the skin/BH attachment is 2 inches. This is what I used along the flat bottom edge. The hole in the BH web (in the photo below) is at the C/L. Pilot holes were pre-drilled at corners of the tabs, but along the relatively flat surface, I used the holes at the 2 inch spacing. Otherwise, there would be a lot of unnecessary rivets. The shear flow is very low in the tail cone - back of the envelope conservative estimate is <100 lbs/in at 10 Gs. Because of the tighter radius around the corners, I opted for the closer spacing. In hindsight, perhaps I shouldn't have done it, but it's done now. The shop heads seem OK.
If anyone has any comment, please let me know. You always want things to look perfect, but it never works out quite that way in reality. I'll borrow the phrase: "Onward & Upward...."
4 Jun 2012 (2.5 hours, total time to date: 344.0 hours)
Finished riveting the bottom tail cone skin to BH128. I over bucked one of the rivets, drilled it out, and re-installed it. The second time was not ideal, but probably not worth drilling out again. I sent a photo to Sean, and he concurred. Polished out the scratches in the web of BH128 caused by my use of the bucking bar, and re-alodined & treated with primer. Finally, started work riveting the bottom skin to BH160 (~1/2 done).
5 Jun 2012 (1.0 hours, total time to date: 345.0 hours)
Justin came over to help me finish riveting along BH160. He drove the rivets while I bucked. It turned out very well - Justin picked it up immediately, and did a great job.
6 Jun 2012 (1.5 hours, total time to date: 346.5 hours)
I fabricated a tool to add more curvature to the top edge of the left and right tail cone skins using 2 in PVC. I attached 2 ft lengths of 1.125 dia. broom handle in two places (2 ft spacing) along the 6 ft length of PVC. This will provide the leverage required to roll the skin.
7 Jun 2012 (1.0 hours, total time to date: 347.5 hours)
Drove 4 rivets along BH177.5. The remaining rivets for the bottom skin attachment at this BH are more difficult to reach. I will wait for help. Started work de-burring the attachment holes for the left tail cone skin.
9 Jun 2012 (1.5 hours, total time to date: 349 hours)
Rob came over to help finish the rivets along BH177.5. After partially driving one, we discovered that we will need a smaller bucking bar to fit inside the tight radius. We then switched gears and used my PVC bending tool to add more curvature to the left and right tail cone skins (along the top edge). This will help make a better fit, and make it much easier to re-install the skins because of the tight radii along the top edge of the tail cone. I also spent a little time removing more of the protective plastic on the skin in preparation for more de-burring and dimpling.
10 Jun 2012 (1 hour, total time to date: 350 hours)
Continued preparing the left tail cone skin for dimpling. I removed the remaining plastic in the areas to be dimpled. Justin stopped by, and I decided to re-bend the top edges of the left & right tail cone skins to get a little better fit. This is a two person job because of the length of the upper edges (~6 ft). It is important to hold the bending tool tight along the length against a flat surface while forming the radius. The skins now appear to have a nice curvature which should allow the upper flange to be roughly normal to the top edge and reduce the force required to fit the skins to the BHs.
16 June 2012
Building has been put on hold temporarily. I'm waiting on some smaller tungsten bucking bars to finish riveting the tight areas around the bottom of BH177.5 and 182. Also, Beth and I recently closed on a new house, and I am getting my new building area ready.
The overhead storage was already there, but was built poorly. It probably took me longer to fix it than it would have to build it from scratch. Justin & Denise came over a couple of times & helped me fix it up. Now, I'm building the workbench for my power tools (disk sander, band saw, drill press, ...)
The overhead storage was already there, but was built poorly. It probably took me longer to fix it than it would have to build it from scratch. Justin & Denise came over a couple of times & helped me fix it up. Now, I'm building the workbench for my power tools (disk sander, band saw, drill press, ...)
30 June 2012
It's getting there. The movers will be here on Friday, July 6, so I need to get some more work done soon.
1 July 2012 (0.5 hour, total time to date: 350.5 hours)
I managed to find a little time to work on the airplane today. The smaller bucking bars arrived, so I finished bucking the rivets along the bottom of BH177.5.
20 July 2012 (3.5 hours, total time to date: 354 hours)
Deburred and dimpled the left tail cone skin. Re-attached the skin to the tail cone in preparation for the move to the new house.
21 July 2012 (2.5 hours, total time to date: 356.5 hours)
De-burred and dimpled the right tail cone skin.Re-attached the skin to the tail cone, and moved the project to the new house (with the help of my brother, Bill).
30 Sep 2012
It took a while, but I finally have the workshop ready to go. A lot of things have been going on, but I can see things starting to settle down. I like the new setup, and I took the time needed to organize the new work space.
5 Oct 2012 (0.5 hour, total time to date: 357 hours
I removed the right skin from the tail cone in preparation to finish riveting the aft end of the bottom skin and to alodine the right and left tail cone skins. Since I have less horizontal storage space, I rigged up a way to hang the skin on a 1x2 suspended from the ceiling.
6 Oct 2012 (2.5 hours, total time to date: 359.5 hours)
Riveted the bottom aft skin to the BH doublers at BH182 & 177.5. Also riveted four locations along the aft end of the fuselage that could be reached (given the 1x2 post supporting the aft tail cone). I initially used a hand squeezer for the aft rivets, but after putting a "smiley" on one rivet, decided to go back to the gun. I'll have to get more practice with the squeezer. I will also need to drill out and replace the bad rivet, but it was late and I was too tired to attempt it at this time.
7 Oct 2012 (0.5 hours, total time to date: 360 hours)
Drilled out the bad rivet done yesterday, and replaced it using the rivet gun. Much better :-)
8 Oct 2012 (2.5 hours, total time to date: 362.5 hours)
De-greased, etched, and alodined the left side tail cone skin. It is now ready to rivet to the tail cone.
9 Oct 2012 (2.5 hours, total time to date: 365 hours)
De-greased, etched, and alodined the right side tail cone skin. I am very happy to have these two skins finished before the cold weather sets in and makes it even more difficult to alodine these large parts.
10 Oct 2012 (2 hours, total time to date: 367 hours)
Began work riveting the left skin to the tail cone. It's a little slow going by myself since I have to be a lot more careful using one hand on the gun and the other holding the bucking bar. The procedure I use is to triple check just about everything, being sure I'm on the rivet, set it, check the shop head for alignment, hit it, check it, hit it check it,,,, So far, I made one goof using a -4 length at the junction of one of the BHs and the bottom/side skin interface. It was too short, and the shop head was not large enough. I had to drill it back out, cut a new rivet to length, and re-install. One thing I've learned about the riveting process - you can't be afraid to drill out a mistake. You get better as you do them.
11 Oct 2012 (1.5 hours, total time to date: 368.5 hours)
Continued riveting the left skin to the tail cone.
12 Oct 2012 (1 hour, total time to date: 369.5 hours)
Continued riveting.........
13 Oct 2012 (3.5 hours, total time to date: 373 hours)
Finished riveting the left side tail cone skin. Justin came over and we were able to drive about 80 rivets in 3 hours. I then clecoed the right skin back on the tail cone in preparation for taking the tail cone out of the jig, turning it right-side-up, and mounting it in the fuselage jig (yet to be built).
There is some dimpling along BH 128. It looks worse than it really is from this angle. I should be able to fill it before painting.
There is some dimpling along BH 128. It looks worse than it really is from this angle. I should be able to fill it before painting.
14 Oct 2012 (2 hours, total time to date: 375 hours)
Started work building the fuselage jig. Double checked the drawing and made slight modification to allow the tail cone to be attached to the jig. Cut the lumber to the proper lengths.
15 Oct 2012 (1 hour, total time to date: 376 hours)
Assembled the base of the jig and the extension to support the tail cone.
17 Oct 2012 (0.5 hour, total time to date: 376.5 hours)
Double checked the tail cone alignment by re-connecting the center line wire to the tail cone jig and noting the reference marks on the 1x4 attached across the C/L of BH99.35. I will use this reference when I move the tail cone to the new fuselage jig.
The drawings show a C/L post aft of BH99.5, but this will not allow the tail cone to be mounted since the skin is attached. I'm not sure how they expected this to be done??? In any case, I will run the wire from the C/L hole in BH177.5 through the reference noted above at BH99.35, and on forward to the post in front of BH52.5 on the fuselage jig.
The drawings show a C/L post aft of BH99.5, but this will not allow the tail cone to be mounted since the skin is attached. I'm not sure how they expected this to be done??? In any case, I will run the wire from the C/L hole in BH177.5 through the reference noted above at BH99.35, and on forward to the post in front of BH52.5 on the fuselage jig.
18 Oct 2012 (0.5 hour, total time to date: 377 hours)
Laid out the position of the fuselage jig and the tail cone support in the work area to minimize the need to move it during assembly.
19 Oct 2012 (1 hour, total time to date: 378 hours)
Assembled a 12 foot 2x2 and 1x4 to be used to attach plumb lines from the garage ceiling.
20 Oct 2012 (2 hours, total time to date: 380 hours)
Aligned and mounted the plumb line support to the ceiling along the A/C center line. Added wooden pads to the fuselage jig to allow it to lay flat on the floor.
27 Oct 2012 (1.5 hours, total time to date: 381.5 hours)
Cut and attached gussets and a 2x6 along the top and bottom (respectively) of the aft edge of the fuselage jig. This should provide plenty of rigidity. Also ran a CL wire on the base of the fuselage jig to assist laying out the fuselage vertical supports.
28 Oct 2012 (4 hours, total time to date: 385.5 hours)
Aligned and attached a 1x2 cross member to set the position of the rear spar carry-thru supports. Aligned and attached the 2x6 which serves as the base for the 3/4 plywood vertical support for BH73.5. It took some time to check and re-check the alignment and position. Clamped and measured the total length required for the steel vertical supports for the rear spar attachments.
29 Oct 2012 (2 hours, total time to date: 387.5 hours)
Continued work on the fuselage jig. Worked on supports to hold the vertical rear spar posts vertical and parallel.
30 Oct 2012 (1.5 hours, total time to date: 389 hours)
Continued working on the jig. Checking alignment & laid out the location of the supports for the vertical posts to maximize rigidity. Began work to fabricate a duplicate rear spar carry-thru using a spare piece of 6061 2x2x0.125 angle stock.
31 Oct 2012 (2 hours, total time to date: 391 hours)
Finished the duplicate rear spar carry-thru and drilled #40 pilot holes on the CL and at the required 22 inch spar attach spacing. I also drilled holes just inboard of the attachment holes to mark the location of the -5 rivets nearest the supports and verify clearance with the posts. Drilling these holes accurately takes some time and reinforces the fact that perfection is relative. I noted that my aluminum yard stick does not match my 18 inch steel rule - off by ~ 1/64 at 18 inches. This made for a lot of second guessing and more checking.
Cut and ground the ends of the steel vertical supports to length drilled the 1/4 jig attachment and support holes, cleaned, & applied a coat of primer on the supports.
Cut and ground the ends of the steel vertical supports to length drilled the 1/4 jig attachment and support holes, cleaned, & applied a coat of primer on the supports.
1 Nov 2012 (2 hours, total time to date: 393 hours)
Aligned and bolted the vertical supports to the fuselage jig. Attached the fore-aft supports to the jig and clamped the ends to the supports. I will wait until the tail cone is mounted to make the final fine alignment and attachment to the supports.
I'm sure there will be some (hopefully slight) difference between the actual rear spar carry-thru and the duplicate. This can really get the OCD juices flowing :-)
I'm sure there will be some (hopefully slight) difference between the actual rear spar carry-thru and the duplicate. This can really get the OCD juices flowing :-)
2 Nov 2012 (2 hours, total time to date: 395 hours)
I decided to re-do the rear spar carry-thru attachment holes by carefully drilling the other side of the duplicate. The spacing was off by about 1/32. Just want to be as close as possible to the correct spacing. Hopefully, it will be a good match to the actual carry-thru. Checked and re-checked the alignment of the duplicate on the jig and match drilled out the attachment holes in the vertical supports. Drilled the left side attachment for the 1x2 diagonal brace and clamped the other end to the right vertical support (I will drill that side once the tail cone is in the jig).
3 Nov 2012 (3 hours, total time to date: 398 Hours)
Transferred the tail cone to the new fuselage jig! The fit seems very good - the extra time and effort paid off.
I used 3/16 bolts to attach the rear spar carry-thru. I will drill the holes out to 1/4 when I attach the wings to get a good, neat final fit. Drilled out the right side of the diagonal brace and bolted everything in place. The aft end of the tail cone is suspended from the ceiling with cargo straps. I ran a new C/L wire from BH177.5 to a temporary vertical 1x2 clamped at the location of BH73.75 and began work to check the C/L alignment of the tail cone.
I used 3/16 bolts to attach the rear spar carry-thru. I will drill the holes out to 1/4 when I attach the wings to get a good, neat final fit. Drilled out the right side of the diagonal brace and bolted everything in place. The aft end of the tail cone is suspended from the ceiling with cargo straps. I ran a new C/L wire from BH177.5 to a temporary vertical 1x2 clamped at the location of BH73.75 and began work to check the C/L alignment of the tail cone.
4 Nov 2012 (2 hours, total time to date: 400 hours)
Continued working on tail cone alignment. Added a temporary vertical post at BH73.75 to establish the tail cone C/L and check against the C/L along the bottom of the fuselage jig. Attached the tail post beam to the fuselage jig via screws to a 2x4 block. Also, fabricated an adjustable tail post to attach to the tail wheel attachment tube. This will allow for more fine tuning of the longitudinal alignment in fuselage pitch. The fixture requires more stiffening, and minor height adjustment.
5 Nov 2012 (1 hour, total time to date: 401 hours)
Shortened the tail post slightly, added a 2x2 stiffener, and did some more alignment checks.
6 Nov 2012 (1 hour, total time to date: 402 hours)
Added a 1x3 on the other side of the 2x2 vertical stiffener for the tail post. This will add more stability and allows the addition of a 2x2 support at the free end of the angle bracket. The angle bracket support was also added. The cargo straps were removed, and the tail cone is now securely supported at three points (2 at the ends of the rear spar carry-thru & 1 at the tail wheel attachment tube).
7 Nov 2012 (1 hour, total time to date: 403 hours)
Verified the tail cone lateral alignment using the C/L wire at BH99.35. Cut 2x4 (4) & 2x6 (1) wood blocks and secured them around the fuselage jig (4) & tail post (1) using liquid nails. This will help keep the jig and post from moving on the floor to avoid changing the alignment.
8 Nov 2012 (1 hour, total time to date: 404 hours)
Riveted the remaining 5 fastener locations along the bottom edge of BH182. These were not accessible when the tail cone was in the tail cone jig. Also, double-checked the tail cone lateral alignment and attached an angle bracket connecting the tail post to the 2x6 wood block that had been glued to the floor to prevent lateral and longitudinal motion.
9 Nov 2012 (2 hours, total time to date: 406 hours)
Re-checked the longitudinal alignment and made a minor adjustment to the position of the C/L wire at the BH73.75 temporary vertical post. A small groove was cut in the post that will help locate the C/L wire for later fuselage construction. Removed the C/L wire in preparation to install the stabilizer spar. Began work to attach the stabilizer spar at BH177.5. Clecoed the upper BH177.5 doubler in place & marked the vertical positions of the spar attachment holes. Also, marked the approximate vertical location of the stabilizer attachments at BH160 to verify clearance with existing skin/BH rivets. It looks good.
10 Nov 2012 (2 hours, total time to date: 408 hours)
Drilled a #30 pilot for the upper center stabilizer spar attachment hole and clecoed the spar to BH177.5. Since the spar is tapered, it is more of a challenge to align it. I spent some time working to level the spar and match drilled a second #30 pilot hole through the lower, center spar attachment hole. I decided that the best way to verify the alignment is to drop a plumb line along the C/L at BH177.5, mark the C/L of the spar 3 ft from the center on each side, and use the 3,4,5 right triangle method.
11 Nov 2012 (3 hours, total time to date: 411 hours)
Ran the plumb line and marked the spar as noted yesterday. Also, measured, marked, and drilled #30 pilot holes on each side of the existing attachment holes in the spar. Clecoed the upper center pilot hole to BH177.5 and measured & marked the plumb line 4 fit above the center of the spar. I marked the C/L of a straight, finished 1x2 and measured off 5 ft. Beth held the 1x2 at the spar tips while I double checked the intersection of the 5 ft mark with the 4 ft plumb line mark. I clamped each side of the spar to a 1x4 to secure the position and made adjustments until satisfied that the spar was level. Once level, I noted the distance of the left spar tip from the floor for future reference.
I match drilled the newly drilled attachment holes to BH177.5, clecoed the holes, and then enlarged each to #21 and clecoed them in place. The final attachment hole size is 3/16, but I need to order nut plates and bolts, so I will wait to finish these holes.
I match drilled the newly drilled attachment holes to BH177.5, clecoed the holes, and then enlarged each to #21 and clecoed them in place. The final attachment hole size is 3/16, but I need to order nut plates and bolts, so I will wait to finish these holes.
12 Nov 2012 (3 hours, total time to date: 414 hours)
Started work to attach the transverse BH (between BHs177.5 and 182). The BH I purchased from Mustang Aero didn't fit my finished product as well as I'd like, so I decided to make a new one. I measured and cut the forming blocks and it took 2 tries before I made one that I liked. However, the fit is now very good. This is one part that I'm sure will be a little different for every airplane - nothing wrong with what MA did. Their part is correct, but with the extra doubler and the reality of construction, it was just a little off for my airplane.
Mine is the one closest to the mallet. I'll be able to use the doubler to the left of it.
Mine is the one closest to the mallet. I'll be able to use the doubler to the left of it.
13 Nov 2012 (1 hour, total time to date: 415 hours)
Started work laying out the attachment holes in the transverse BH. I want to have inspection capability between BH177.5 & 182, so I added a 0.040 reinforcing ring to fit under the transverse BH doubler. The inspection hole will be 2 inches in diameter and I will add a 0.032 inspection cover on top. The ring will have 8 concentric attachment holes - 4 will be standard 1/8 universal head rivets, and 3 will be #8 machine screws (1 #10 to provide orientation for the cover) to allow the cover to be removed. Over-sized holes will be cut in the cover as needed to provide clearance for the rivet heads.
14 Nov 2012 (1 hour, total time to date: 416 hours)
Continued working on the transverse BH components. Drilled pilot holes for the reinforcing ring and additional attachment pilot holes in the BH & doubler.
15 Nov 2012 (1 hour, total time to date: 417 hours)
Decided to use a thicker (0.063) reinforcing ring and make it slightly wider (0.7+) to accommodate the machine screws. started work to fabricate a new ring.
16 Nov 2012 (2 hours, total time to date: 419 hours)
Cut out the center of the new reinforcing ring using a fly cutter on the drill press. Cut the outside diameter with the band saw and cleaned it up with the disk sander and scotch brite wheel. Also, decided to make a new transverse BH doubler because the flange was not quite square on the one from MA. I want to be sure to have good margins for the fin spar attach bolts. I fabricated a new doubler and drilled out the pilot web attachment holes.
18 Nov 2012 (2 hours, total time to date: 421 hours)
Cut the inspection hole in the web of the BH and doubler. Laid out and drilled the #40 pilot attachment holes in the left and right flanges of the BH. Finished the inspection cover and drilled a #30 pilot hole in the aft inspection cover attachment hole (for indexing purposes). De-burred and finished the edges.
19 Nov 2012 ( 2 hours, total time to date: 423 hours)
Drilled the #40 tail cone skin attachment holes at each side of the upper end of BH182. I held off because I was not sure how the transverse BH would fit. Now, I know this was a mistake since I don't think I will be able to dimple this location because the skin is already riveted to the left side. I experimented using my rivet gun with a dimple die on two pieces (0.025/0.032), and it did not work well. The die makes deep ring marks because of the force required to make the dimple. I will use universal head rivets here instead.
Started work getting the transverse BH, ring, and doubler fitted between BH177.5 & BH182. The transverse BH needs to be level with the C/L, the top of the forward flange must clear the C/L hole in BH177.5, and the aft flange needs to have proper edge margins for the upper fin spar attachment bolts.
Started work getting the transverse BH, ring, and doubler fitted between BH177.5 & BH182. The transverse BH needs to be level with the C/L, the top of the forward flange must clear the C/L hole in BH177.5, and the aft flange needs to have proper edge margins for the upper fin spar attachment bolts.
20 Nov 2012 ( 1 hour, total time to date: 424 hours)
Clamped the transverse BH side and aft flanges in position, used a 12 in. #41 drill bit to match drill the flange attachment holes to the skins & BH177.5 web. The long bit can be flexed around the edges of the flanges. I clecoed the assembly as I went.
The 0.063 reinforcing ring is under the doubler and the 0.032 inspection cover will go on top.
The transverse BH is now fitted to the tail cone. The aft flange will be bolted to the fin spar at two locations, 2 inches apart. I marked the approximate location on the web of BH182 with a permanent marker (these dots are barely visible in the photo). Nut plates will be mounted once the fin spar is aligned and the attachment holes have been drilled. The lower fin spar attachment hole is at the bottom of the BH182 web and the nut plate is in place.
The 0.063 reinforcing ring is under the doubler and the 0.032 inspection cover will go on top.
The transverse BH is now fitted to the tail cone. The aft flange will be bolted to the fin spar at two locations, 2 inches apart. I marked the approximate location on the web of BH182 with a permanent marker (these dots are barely visible in the photo). Nut plates will be mounted once the fin spar is aligned and the attachment holes have been drilled. The lower fin spar attachment hole is at the bottom of the BH182 web and the nut plate is in place.
21 Nov 2012 (1 hour, total time to date: 425 hours)
Re-ran a plumb line in front of BH99.35 to double check that the tail cone has not moved and is level wrt the C/L.BH99.35 should be canted so that the top of the web is 6.25 inches aft of station 99.35 - this checked out. Now that the transverse BH has been leveled, it provides another reference plane.
While fitting the trnsverse BH, I noted that BH 177.5 is not perpendicular to the C/L. in the lateral plane. The BH must have moved during the skin fitting process. I will need to add shims to the BH so that the stabilizer spar will be laterally perpendicular to the C/L. Started measuring for shims.
While fitting the trnsverse BH, I noted that BH 177.5 is not perpendicular to the C/L. in the lateral plane. The BH must have moved during the skin fitting process. I will need to add shims to the BH so that the stabilizer spar will be laterally perpendicular to the C/L. Started measuring for shims.
22 Nov 2012 (2.5 hours, total time to date: 427.5 hours)
Steve Horii is visiting for Thanksgiving and came over to look at the airplane and help me work on the stabilizer shims. I cut several shims and checked the spar by measuring each end from its respective side of BH99.35 at the C/L. After several tries, we finally got the dimensions worked out. The shims will need to be slightly tapered on one edge to allow the spar to seat correctly and minimize out of plane bending across the bearing surfaces.
I also decided to re-fabricate the 0.063 aluminum doubler for BH177.5 because the edge margins for the spar attachment holes were slightly low on each side of the original doubler plate.
I also decided to re-fabricate the 0.063 aluminum doubler for BH177.5 because the edge margins for the spar attachment holes were slightly low on each side of the original doubler plate.
23 Nov 2012 (1.5 hours, total time to date: 429 hours)
Carefully checked the shim fits and worked on tapering the required edges. The goal is to remove material on one edge to reduce the gap caused by the angle between the BH web and spar. The shim needs to be approx. 0.75+ inches wide to provide a proper edge margin for the attachment holes and some room for attaching nut plates, but without some edge taper, the spar will contact one edge of each shim. This would cause unwanted bending when the bolts are tightened. A little more adjustment work is still needed. The area around each hole will be left flat to provide a good bearing surface. This will induce some bending (as noted), but much less than would occur without some edge taper.
The shims will be held in place with the nut plate satellite rivets, and I will add a flush 1/8 rivet between (vertically) the spar attachment holes to provide good attachment over the height of the spar. For now, I have cut the shims long and am using the doubler clecos to hold the shims for fitting purposes.
The shims will be held in place with the nut plate satellite rivets, and I will add a flush 1/8 rivet between (vertically) the spar attachment holes to provide good attachment over the height of the spar. For now, I have cut the shims long and am using the doubler clecos to hold the shims for fitting purposes.
24 Nov 2012 (2 Hours, total time to date: 431 hours)
Continued working on tapering the shims. I taped the shims to the work bench, and used a pneumatic disk sander to carefully remove material and polish the surface. I replaced the shims, mounted the spar using #21 clecos, and checked the fit using a flash light under the spar. I repeated the process as needed.
25 Nov 2012 (1.5hours, total time to date: 432.5 hours)
Began work mounting the fin spar. Ran a plumb line through the rudder hinge and attached the existing bottom 3/16 bolt. I clamped the spar to the transverse BH flange, and aligned the spar with the plumb line. Drilled the pilot attachment holes - first with a #30 and then with a #21 bit.
Now that the fin spar is in place, I can make a final adjustment to the stabilizer spar by measuring off of the tip of the vertical fin spar.
Now that the fin spar is in place, I can make a final adjustment to the stabilizer spar by measuring off of the tip of the vertical fin spar.
30 Nov 2012 (2 hours, total time to date: 434.5
Removed the fin spar. Decided to re-fabricate the 0.063 right shim. Tapered it more carefully and checked the fit (it took about 4 times to get things where I wanted them). Made some minor adjustments to the center shim as well.
1 Dec 2012 (2.5 hours, total time to date: 437 hours)
Built 2 wooden stands to hold the stabilizer in place. Initially, they will hold the spar in place while I make final alignment adjustments using the fin spar to verify the two are perpendicular. It was much easier to align the fin spar, and once it was in place, it is also easy to check the horizontal spar based on the distance from the tips of each side. The stabilizer was off approx. 1/32 (not bad - too high on the left side).
I drilled the upper center attachment to 3/16 and installed a temporary bolt. Replaced the fin spar (using -5 clecos at the top two attach points), and made the required stabilizer spar adjustment (rotating at the temp bolt). Clamped the spar in place to the new stands, and removed the fin spar. Re-drilled the #21 pilot holes and installed a temporary cleco at the bottom center hole. Drilled out the remaining holes (#19, then 3/16), and installed 2 temporary bolts at the bottom left and right. Finally, drilled the center bottom hole to size.
Now, the spar attachment area is ready to be cleaned up and prepared for final assembly.
I drilled the upper center attachment to 3/16 and installed a temporary bolt. Replaced the fin spar (using -5 clecos at the top two attach points), and made the required stabilizer spar adjustment (rotating at the temp bolt). Clamped the spar in place to the new stands, and removed the fin spar. Re-drilled the #21 pilot holes and installed a temporary cleco at the bottom center hole. Drilled out the remaining holes (#19, then 3/16), and installed 2 temporary bolts at the bottom left and right. Finally, drilled the center bottom hole to size.
Now, the spar attachment area is ready to be cleaned up and prepared for final assembly.
2 Dec 2012 (1 hour, total time to date: 438 hours)
I decided to re-fabricate another shim, then checked the fit and alignment. Everything looks good. Also removed the BH177,5 doubler and de-burred the spar attachment holes.
3 Dec 2012 (2 hours, total time to date: 440 hours)
Drilled the transverse BH flange attachment holes to #31 and removed the right side skin in preparation to install the 6 nut plates for the stabilizer spar. Began work fitting the nut plates. I made a "washer" from 0.25 in. thick stock to help align the bolts when using the nut plates as a guide to drill the attachment holes.
4 Dec 2012 (4 hours, total time to date: 444 Hours)
Aligned and drilled the 6 stabilizer spar nut plate attach holes. I cut a 3/16 bolt down to about 5 threads so I could get the bolt shank to seat in the nut plate by hand and be sure the bolt shank was engaged in all layers before drilling each satellite hole (using a nut plate as a drilling template). Also drilled the center rivet holes for the two vertical shims.
Removed all of the clecos and de-burred the holes.Finished the BH web and doubler with scotch brite pads. Finally, de-greased, and used a self-etching primer to protect the parts prior to assembly.
Removed all of the clecos and de-burred the holes.Finished the BH web and doubler with scotch brite pads. Finally, de-greased, and used a self-etching primer to protect the parts prior to assembly.
5 Dec 2012 (1 hour, total time to date: 445 hours)
Cut the shims to their final length. Cleaned up the edges, de-greased, and primed with a self-etching primer.
6 Dec 2012 (1 hour, total time to date, 446 hours)
Riveted BH177.5 doubler in place. Temporarily installed 6-3/16 bolts in the attachment holes to keep the doubler in place while installing the 10, -4 rivets along the top and bottom of the doubler.
7 Dec 2012 (2 hours, total time to date: 448 hours)
Installed the shims and nut plates. My friend, Alex came over and helped me (he bucked the nut plate attach rivets). I also installed a -4 rivet at the center of each shim to help hold them tightly to the BH/Doubler and provide a more load carrying capability through the shims.
8 Dec 2012 (2 hours, total time to date: 450 hours)
Measured the location of the front stabilizer root rib attachment points on the flange of BH160. The attachment holes will be drilled through the skin, and I want end up with a decent edge margin for the 3/16 bolts. The flange provided with the kit BH is relatively narrow for the 3/16 bolt, so I don't have a lot of room to "play." It looks like I'll end up with just a little over 1.5 edge margin.
I then re-installed the right skin and marked the drill line on each skin (right and left).
I then re-installed the right skin and marked the drill line on each skin (right and left).
16 Dec 2012 (1 hour, total time to date: 451 hours)
Worked on the Transverse BH. Drilled out the doubler and reinforcing ring attachment holes to #30 (except the aft ring hole - #21). Also re-installed the fin spar and drilled out the upper attachment holes to 3/16 (including the lower hinge attach bracket).
17 Dec 2012 (1 hour, total time to date: 452 hours)
Fabricated a nut plate drilling jig from some scrap 0.25 thick 6061-T6. Drilled the nut plate holes for the upper fin spar attach points.
18 Dec 2012 (2 hours, total time to date: 454 hours)
Removed the transverse BH components and de-burred the holes. Re-assembled the components, and drilled out the appropriate holes through the reinforcing ring for the 3-#8 and 1-#10 cover plate screws.
Disassembled the BH components, de-burred, and finished the parts in preparation for dimpling and priming.
Disassembled the BH components, de-burred, and finished the parts in preparation for dimpling and priming.
19 Dec 2012 (2 hours, total time to date: 456 hours)
Dimpled the tail cone skins and corresponding transverse BH flange holes. Dimpled the nut plate attach holes on the transverse BH/doubler webs, and countersunk the nut plate attach holes in the reinforcing ring. Dimpled the nut plate holes for the fin spar in BH182, and countersunk the corresponding holes in the doubler flange.
I used a vice-grip dimpler for the #30 tail cone, #40 fin spar attach nut plate holes and flange holes then hit them carefully using my #3 rivet gun with a dimple die (to help flatten the area around the dimples) to minimize surface marks. I used my dimpling table for the #40 nut plate holes in the BH/doubler webs, and countersunk the nut plate holes in the reinforcing ring and doubler flange using my hand de-burring tool with a countersink bit.
I used a vice-grip dimpler for the #30 tail cone, #40 fin spar attach nut plate holes and flange holes then hit them carefully using my #3 rivet gun with a dimple die (to help flatten the area around the dimples) to minimize surface marks. I used my dimpling table for the #40 nut plate holes in the BH/doubler webs, and countersunk the nut plate holes in the reinforcing ring and doubler flange using my hand de-burring tool with a countersink bit.
20 Dec 2012 (2 hours, total time to date: 458 hours)
Finished and de-greased the transverse BH components and used a self-etching primer to provide some corrosion protection in preparation for assembly. Drilled out the attachment and rivet head clearance holes in the transverse BH inspection cover.
21 Dec 2012 (1 hour, total time to date: 459 hours)
Started dimpling the tail cone forward access panel doubler. I'm using #8 countersunk screws t attach the covers, and decided to install one countersunk nut plate on a scrap piece of 0.032 sheet to look for any potential problems. I dimpled the attach holes and was also able to dimple the nut plate holes adequately. I dimpled all of the #8 screw holes in the forward cover, and started working on the #30 doubler attach holes.
22 Dec 2012 (3 hours, total time to date: 462 hours)
Justin came over for an early Christmas dinner and helped me rivet the Transverse BH components, including the nut plates. We installed the assembled BH in the tail cone and riveted the left side and fin spar attach nut plates.
The extra hands were invaluable, and Justin is very good with the bucking bar. I had to drill out a few rivets, but I'm sure I would have had many more without his help - not to mention the amount of time saved. The end result looks pretty darn good!
The extra hands were invaluable, and Justin is very good with the bucking bar. I had to drill out a few rivets, but I'm sure I would have had many more without his help - not to mention the amount of time saved. The end result looks pretty darn good!
23 Dec 2012 (1 hour, total time to date: 463 hours)
Finished dimpling the #30 holes in the forward tail cone access panel doubler and bolted the stabilizer spar on BH1777.5 using shortened 3/16 bolts (avoiding overworking the nut plates).
24 Dec 2012 (1 hour, total time to date: 464 hours)
Used a smart level w/laser to verify the stabilizer C/L intersection at BH160. Re-checked tail cone and spar alignment before starting work building the stabilizer on the tail cone. The spar is level to less than 1/32 in. between the outboard hinge fittings, and laterally square to approx. 1/4 in. laterally tip to tip (measured from the rear wing spar attach). I will double check the alignment of the 3 hinge fittings before fitting the skin.
25 December (1 hour, total time to date: 465 hours)
Merry Christmas!
I spent a good deal of time going over the plans and construction details for the stabilizer before cutting any metal today. Started work laying out the attachment holes for the stabilizer root ribs and spar. Removed the spar and drilled #40 pilot holes (3 on each side) in the spar for each rib. I should have installed bolts in the outboard upper and lower attach points to hold the spar doublers to the spar web to help avoid getting drill shavings between the layers. I used a feeler gauge to clear them out.
I spent a good deal of time going over the plans and construction details for the stabilizer before cutting any metal today. Started work laying out the attachment holes for the stabilizer root ribs and spar. Removed the spar and drilled #40 pilot holes (3 on each side) in the spar for each rib. I should have installed bolts in the outboard upper and lower attach points to hold the spar doublers to the spar web to help avoid getting drill shavings between the layers. I used a feeler gauge to clear them out.
26 Dec 2012 (1.5 hours, total time to date: 466.5 hours)
Fit the H/Stab root ribs to the spar. Marked a line on each rib flange 21/64 in. from the outer web face (left 17/64 edge margin). Cut two (3/4 x 2) strips from some scrap 0.032 sheet and clamped them to the spar & rib flanges to be sure the ribs are properly positioned on the spar (flanges are flush and ribs are centered). Matched drilled & de-burred the #40 pilot holes through the drilling line (visible through the existing holes in the spar). I installed bolts in the outer pair of spar attach holes to help hold the spar doublers tight against the spar web to minimize getting more drilling chips between the two layers. Repeated this on the other root rib and re-attached the spar to BH177.5 to look at the location of the rib tips wrt BH160. They are closer than I'd like (~1/4 in. aft) and the right is slightly closer. I've hear about this from another builder (I think his were even further forward and he had to install doublers in the fuselage to accommodate the forward rib attach bolt and nut plate. In my case, I'd end up overlapping the edge of the BH flange, so I will not do this. I may have to work with what I have and use shims inside the ribs to fill the gap between the rib flanges and the forward fittings (since I will have to move the fittings further aft in the ribs).
27 Dec 2012 (1 hour, total time to date: 467.5 hours)
Laid out the location of the forward stabilizer attach holes along the stab C/L to center them on the flanges of BH160. Since the flanges are not wide enough to provide an adequate edge margin for the 3/16 bolt, I plan to add a doubler inside the inner corners of the BH, so there needs to be enough room between the BH web and the attach holes to accommodate them.
Carefully drilled out the holes progressing in size (#50, #40, #30, #25, and #21) to aid in positioning and minimize the chance of introducing chips between the already riveted left skin and the BH. The forward fittings were provided with #21 holes, and I will cleco them in place for now while I finish attaching the tip rib and forward spar. Later, when I have removed the right skin, I will attach the doublers and finish drilling the holes to 3/16. I will also add a 0.032 doubler/washer on the outside of the skin to provide material to countersink the nut plate attach holes. I don't like the idea of countersinking the thin skin, and it can't be dimpled since it's already attached to the BH on the left side.
Carefully drilled out the holes progressing in size (#50, #40, #30, #25, and #21) to aid in positioning and minimize the chance of introducing chips between the already riveted left skin and the BH. The forward fittings were provided with #21 holes, and I will cleco them in place for now while I finish attaching the tip rib and forward spar. Later, when I have removed the right skin, I will attach the doublers and finish drilling the holes to 3/16. I will also add a 0.032 doubler/washer on the outside of the skin to provide material to countersink the nut plate attach holes. I don't like the idea of countersinking the thin skin, and it can't be dimpled since it's already attached to the BH on the left side.
28 Dec 2012 (1 hour, total time to date: 468.5 hours)
Fit the H/Stab tip ribs to the spar using the same method I used for the root ribs.
29 Dec 2012 (1.5 hours, total time to date: 470 hours)
Bolted the H/Stab spar back on BH177.5. Laid out the rivet locations on the ribs & used fluting pliers between the rivet locations to straighten each rib. Clecoed the ribs back to the spar in preparation to fit the front spar.
30 Dec 2012 (3 hours, total time to date: 473 hours)
Trimmed the nose of the stabilizer root ribs to provide clearance for the attach bolts. Cut blanks to be used as external doublers and shims for the attach fittings. Laid out the rivet pattern for the left root attach fitting. Drilled out the left attachment hole to 3/16. Re-attached the left stabilizer rib, bolted the fitting to the fuselage, Double checked the alignment, and drilled the #40 pilot holes to attach the left root rib to the attach fitting.
31 Dec 2012 (2 hours, total time to date: 475 hours)
Laid out the rivet pattern for the right root attach fitting. Also, needed to trim the nose of the right root rib a little more. Drilled out the right attachment hole to 3/16. Re-attached the right stabilizer rib, bolted the fitting to the fuselage, Double checked the alignment, and drilled the #40 pilot holes to attach the left root rib to the attach fitting.
1 Jan 2013 (4 hours, total time to date: 479 hours)
Fabricated forming blocks (3/4 inch thick oak) to bend the end flanges of the stabilizer front rib. Two sets of blocks were needed since the spar is tapered. Used my disk sander to create a generous 1/8 bend radius for the inside block of both sets.
Stated work fitting the front stabilizer spars. Drilled pilot holes in the root end of the left spar and formed the flange using the forming blocks & finished the bend using a flanging tool I purchased from Grove Air.. Laid out the spar and discovered that it was approx. 1/4 inch too long to properly fit (the spar must match the thickness of each rib at the attach point, and the tip rib is perpendicular to the rear spar). I carefully cut the flanges back slightly less than 1/4 inch, and machined a 3/16 notch using a dremmel tool at the new bend line. Cleaned up the edges using a scotch brite wheel, formed the end flange, trimmed the excess from the end flange, drilled the pilot #40 attach hole, and fit the left front spar to the tip rib.
Stated work fitting the front stabilizer spars. Drilled pilot holes in the root end of the left spar and formed the flange using the forming blocks & finished the bend using a flanging tool I purchased from Grove Air.. Laid out the spar and discovered that it was approx. 1/4 inch too long to properly fit (the spar must match the thickness of each rib at the attach point, and the tip rib is perpendicular to the rear spar). I carefully cut the flanges back slightly less than 1/4 inch, and machined a 3/16 notch using a dremmel tool at the new bend line. Cleaned up the edges using a scotch brite wheel, formed the end flange, trimmed the excess from the end flange, drilled the pilot #40 attach hole, and fit the left front spar to the tip rib.
2 Jan 2013 (3 hours, total time to date: 482 hours)
Fit the right forward stabilizer spar using the same procedures as I used for the left. The right spar was also about 1/4 inches too long (I took that as a good sign). I thought I'd be able to do this one in less time, but it took about the same time as the left (less the time to fabricate the forming blocks). I used a flanging tool that I purchased from Grov-Air to finish the end flange to 90 degrees.
3 Jan 2013 (0.5 hour, total time to date: 482.5 hours)
Laid out and drilled a third pilot hole in the center of the left forward spar/root rib attach point. I decided to add the third rivet when I was working on the right side.
4 Jan 2013 (1.5 hours, total time to date: 484 hours)
Drilled out the pilot holes for the stabilizer spars/ribs/nose attach points to #30 in preparation for assembly. I did as many as possible while on the tail cone, but the single attach points for the tip rib needed to be done when removed. Also, the holes in the forward spar flange connection to the root rib were difficult to reach using a standard 6 inch bit, and I didn't want to risk damage to the tail cone if I used a 12 inch bit, so I finished most of those off of the tail cone.
I removed the stabilizer from the tail cone, finished drilling the #30 attach holes, and dis-assembled the ribs, spars, and forward attach fittings for deburring.
I removed the stabilizer from the tail cone, finished drilling the #30 attach holes, and dis-assembled the ribs, spars, and forward attach fittings for deburring.
5 Jan 2013 (2.0 hours, total time to date: 486 hours)
De-burred, finished, de-greased, & used a self-etching primer to coat the mating surfaces of the stabilizer ribs and front spar.
6 Jan 2013 (3.0 hours, total time to date: 489 hours)
Riveted the forward fittings to the left & right stabilizer root spars. I decided to hold off on assembling the rest of the parts since they take up less space right while I'm fitting the fin structure.
Marked a line along the top edge of the right tail cone skin (where it intersects with the left skin). This is the crown line of the tail cone. I marked the "line-of-sight" in front of the airplane to verify that the tail cone does not deflect when the right skin is removed for installation of the stabilizer nut plates to facilitate installation of the fin. I removed the right skin and the tail cone did not move - based on the "line of sight." I then re-installed the fin spar using shortened bolts as mentioned earlier to minimize damage to the nut plates.
Marked a line along the top edge of the right tail cone skin (where it intersects with the left skin). This is the crown line of the tail cone. I marked the "line-of-sight" in front of the airplane to verify that the tail cone does not deflect when the right skin is removed for installation of the stabilizer nut plates to facilitate installation of the fin. I removed the right skin and the tail cone did not move - based on the "line of sight." I then re-installed the fin spar using shortened bolts as mentioned earlier to minimize damage to the nut plates.
7 Jan 2013 (2 hours, total time to date: 491 hours)
Started work laying out the fin ribs and front spar. There is very limited space for the forward attachment hole at BH160, so it looks like I will have to fit the fin root rib based on the location of that hole.
I carefully measured, checked, and double-checked the location of the forward fin attachment hole. It is supposed to be 3/16 to the left of the C/L, so I also re-checked the location of the C/L. I can't see any way to install a standard nut plate in on the BH160 flange, so I will use a plain nut since the location can be reached through the forward tail cone inspection hole. I located the hole in the flange so that a 3/16 washer will seat properly and provide the best possible edge margin. I fabricated 2 small dimpled washers (using scrap 0.025 material), and used a temporary bolt to securely hold the top of the left skin to the BH.
I drilled the pilot hole from the inside using a manual hand drill with a #40 bit. I then enlarged the hole carefully to 3/16 in increments (#30, #27, #21, #19, 3/16). It seems to have worked out well.....
I carefully measured, checked, and double-checked the location of the forward fin attachment hole. It is supposed to be 3/16 to the left of the C/L, so I also re-checked the location of the C/L. I can't see any way to install a standard nut plate in on the BH160 flange, so I will use a plain nut since the location can be reached through the forward tail cone inspection hole. I located the hole in the flange so that a 3/16 washer will seat properly and provide the best possible edge margin. I fabricated 2 small dimpled washers (using scrap 0.025 material), and used a temporary bolt to securely hold the top of the left skin to the BH.
I drilled the pilot hole from the inside using a manual hand drill with a #40 bit. I then enlarged the hole carefully to 3/16 in increments (#30, #27, #21, #19, 3/16). It seems to have worked out well.....
8 Jan 2013 (2 hours, total time to date: 493 hours)
Re-checked the location of the tail cone C/L, and laid out the location of the attachment hole in the forward root rib fitting. I made a very minor adjustment to the hole location (~1/32) on the C/L of the fitting to place the C/L of the rib to the 3/16 left offset from the tail cone C/L. If there is any error, I'd rather be closer to the C/L. I also adjusted the hole slightly aft of the center of the attachment pad so that the fitting will seat well in the root rib. As was the case with the stabilizer, the BH160 flange is slightly aft of the optimum location for the kit parts.
I also laid out the location of the fin root rib rear flange on the fin spar. The attachment holes through the fin spar will need to be drilled through the aft end of the spar, so I located the edge of the rib flange, removed the spar, located the holes, and drilled the 3 attachment pilot holes in the spar. I then replaced the spar on the tail cone in preparation to match drill the holes in the root rib flange.
I also laid out the location of the fin root rib rear flange on the fin spar. The attachment holes through the fin spar will need to be drilled through the aft end of the spar, so I located the edge of the rib flange, removed the spar, located the holes, and drilled the 3 attachment pilot holes in the spar. I then replaced the spar on the tail cone in preparation to match drill the holes in the root rib flange.
9 Jan 2013 (1.5 hours, total time to date: 494.5 hours)
Aligned the fin root rib on the rear spar & match drilled the #40 pilot attach holes in the rib flange. I clamped 2 strips of scrap 0.032 on each side of the spar to center the rib, leveled the web, and drilled the holes through the aft side of the spar. I clecoed the flange in place, then marked the position of the steel front attach fitting through the tooling hole in the root rib. I removed the root rib and laid out & drilled the pilot holes in the root rib nose to attach it to the steel front fitting. I replaced the root rib, and match drilled the pilot holes in the front fitting (making sure to hold the rib flat against the fitting to maintain the rib C/L along the 3/16 left offset at the forward attach point). The rib twists slightly from the root to the tip because of the offset, the tail cone crown curvature, and the overlapping skin at the crown. I then clecoed the rib back in place to admire my effort. :-)
10 Jan 2013 (1.5 hours, total time to date: 496 hours)
Started work to fit and attach the fin tip and front spars. Removed the fin spar from the tail cone, located, & drilled a #40 pilot hole at the top of the spar to connect the fin tip rib. Marked the drill line on the fin tip rib flange, aligned the tip rib by clamping 2 strips of 0.032 on each side of the spar flange with the drill line visible through the pilot hole (the fin spar was horizontal on the work bench with the tip overhanging the edge). Taped the rib flange to the spar & match drilled the #40 pilot hole in the rib flange.
The end flanges of the front fin spar were not pre-bent (just like the stabilizer front spars). Since the root flange is wider than the root flange of the stabilizer spars, I fabricated a new set of oak bending blocks to fit. The fin root rib has a 0.062, centered pilot hole locating the longitudinal attachment point for the front spar. I laid out the drill line on the un-bent front spar flanges (9/32 from the end), and drilled #40 pilot holes in the tip and the outside holes in the root flange. To make the flange bends, I taped the bending blocks in place, clamped the blocks in the bench vise, and used a rubber mallet to make the bend over the 1/8 radius in the blocks. I used my flanging tool to finish the bend on the root end, but since the tip will not fit in the tool, I used hand pliers with duct tape to protect the aluminum.
The end flanges of the front fin spar were not pre-bent (just like the stabilizer front spars). Since the root flange is wider than the root flange of the stabilizer spars, I fabricated a new set of oak bending blocks to fit. The fin root rib has a 0.062, centered pilot hole locating the longitudinal attachment point for the front spar. I laid out the drill line on the un-bent front spar flanges (9/32 from the end), and drilled #40 pilot holes in the tip and the outside holes in the root flange. To make the flange bends, I taped the bending blocks in place, clamped the blocks in the bench vise, and used a rubber mallet to make the bend over the 1/8 radius in the blocks. I used my flanging tool to finish the bend on the root end, but since the tip will not fit in the tool, I used hand pliers with duct tape to protect the aluminum.
11 Jan 2013 (1.5 hours, total time to date: 497.5 hours)
Removed the fin root and tip ribs from the tail cone and fin rear spar. Aligned and match drilled the #40 pilot holes to attach the front fin spar to the root and tip ribs using the same method described earlier.
Clecoed the parts back on the airplane and drilled out the pilot holes to #30 in preparation for assembly. I used a stop drill for the holes in the front fitting to avoid damaging the tail cone, and it was necessary to remove the front spar, root, & tip rib to drill those attachment holes on the work bench.
Clecoed the parts back on the airplane and drilled out the pilot holes to #30 in preparation for assembly. I used a stop drill for the holes in the front fitting to avoid damaging the tail cone, and it was necessary to remove the front spar, root, & tip rib to drill those attachment holes on the work bench.
12 Jan 2013 (4.0 hours, total time to date: 501.5 hours)
Used fluting pliers to straighten the root and tip ribs. De-burred, finished, de-greased, and used a self-etching primer on the mating surfaces of the fin ribs and spars.
Fabricated a joggling tool by cutting a 1/8 slit in the center of a 4.25 x 2 scrap piece of 0.032 sheet. I decided to add some reinforcement to the stabilizer and fin front fittings. Chances are, they won't be needed, but now would be the time to do add them & they will provide quite a bit of additional capability. A 0.032 joggle is needed to install an internal doubler to attach to the skin and BH160 flange. I cut the doubler blanks and formed the joggle by inserting the blanks in the tool with the joggle line along the slot. I used some blue painter's tape on the tool to help protect the parts. I sandwiched the tool between two pieces of 3/4 thick oak, and used my bench vice to form the joggles. I fabricated the two doublers and drilled the #40 pilot holes in the skin for the left doubler. The outside edge margins for the doubler bolt holes (at the BH flange) is short (~0.22), but should carry an additional 400 lbs ultimate. The position of the 1/8 rivets will be more than enough to carry that load into the skin. The 0.025 skin along (with the BH support) is good for ~500 lbs, so this will be extremely conservative for a 1000 lb airplane with a 10/1 ratio of stab to wing distance from the airplane c..g.. However, this will also provide more bolt bearing area - which I like since I'll be removing the stabilizer many more times.
Fabricated a joggling tool by cutting a 1/8 slit in the center of a 4.25 x 2 scrap piece of 0.032 sheet. I decided to add some reinforcement to the stabilizer and fin front fittings. Chances are, they won't be needed, but now would be the time to do add them & they will provide quite a bit of additional capability. A 0.032 joggle is needed to install an internal doubler to attach to the skin and BH160 flange. I cut the doubler blanks and formed the joggle by inserting the blanks in the tool with the joggle line along the slot. I used some blue painter's tape on the tool to help protect the parts. I sandwiched the tool between two pieces of 3/4 thick oak, and used my bench vice to form the joggles. I fabricated the two doublers and drilled the #40 pilot holes in the skin for the left doubler. The outside edge margins for the doubler bolt holes (at the BH flange) is short (~0.22), but should carry an additional 400 lbs ultimate. The position of the 1/8 rivets will be more than enough to carry that load into the skin. The 0.025 skin along (with the BH support) is good for ~500 lbs, so this will be extremely conservative for a 1000 lb airplane with a 10/1 ratio of stab to wing distance from the airplane c..g.. However, this will also provide more bolt bearing area - which I like since I'll be removing the stabilizer many more times.
13 Jan 2013 (3.0 hours, total time to date: 504.5 hours)
Started work to rivet the stabilizer ribs and spars together, but found it very difficult to set the rivets by myself. I have been able to successfully set flush head rivets using one hand on the gun, but the universal heads require much more attention. The universal head set tends to bounce off of the rivet and after 5/5 drill-outs, I called Alex and asked him to come over and buck the rivets. He didn't have time to stay until we were finished with the stabilizer, but only have 4 more rivets to go.
I also fabricated a larger joggling tool (0.050 x 6.25 total length) to use on the fin forward attachment bolt reinforcement. Chris Tieman (Mustang Aero) strongly recommended adding some reinforcement as insurance in case the aft transverse BH fails. Although I have beefed-up that BH with a 0.063 reinforcing ring, it won't hurt to add an external doubler for the fin fitting. A joggle is needed in the doubler to fit over the skin overlap at the tail cone crown line. I cut the doubler blank and formed the joggle as described for the stabilizer internal doublers. There is no room for an internal doubler for the fin fitting, although, an internal backing plate will be needed forward of BH160. I drilled the nut plate holes for the left front stabilizer, and dimpled the attachment holes in the left skin and doubler. Finally, I de-burred, de-greased, and primed the inside surface of the doubler in preparation for final installation of the left doubler and nut plate.
I also fabricated a larger joggling tool (0.050 x 6.25 total length) to use on the fin forward attachment bolt reinforcement. Chris Tieman (Mustang Aero) strongly recommended adding some reinforcement as insurance in case the aft transverse BH fails. Although I have beefed-up that BH with a 0.063 reinforcing ring, it won't hurt to add an external doubler for the fin fitting. A joggle is needed in the doubler to fit over the skin overlap at the tail cone crown line. I cut the doubler blank and formed the joggle as described for the stabilizer internal doublers. There is no room for an internal doubler for the fin fitting, although, an internal backing plate will be needed forward of BH160. I drilled the nut plate holes for the left front stabilizer, and dimpled the attachment holes in the left skin and doubler. Finally, I de-burred, de-greased, and primed the inside surface of the doubler in preparation for final installation of the left doubler and nut plate.
14 Jan 2013 (1.0 hours, total time to date: 505.5 hours)
Started forming the curvature in the external fin front attach doubler using worm gear clamps around a 15 oz. can. I protected the doubler using some duct tape. The process flattens out the joggle somewhat, but I expected that to happen (made the initial joggle ~0.050). Making the joggle a little deeper, was a good idea. I will need to add more curvature before it will fit properly at BH160. Also, replaced the right tail cone skin and will use #4 c/s machine screws to temporarily attach the crown line between BH160 & 177.5 so I can attach the fin and begin fitting the skin. I installed the screws in two locations using dimpled washers fabricated earlier. It was awkward installing the washers and nuts on the inside due to the limited access. I will make new washers with tabs and tape them to the inside of the skin. This should save some time.
15 Jan 2013 (1.5 hours, total time to date: 507.0 hours)
Finished forming the curvature in the external fin attach doubler (my bicycle tire pump had the right O.D. ~2.25). Fabricated more dimpled washers for the tail cone crown line including a tab to allow me to tape them inside the tail cone. Removed the right skin (again). Also cut and formed the internal backing plate for the fin forward attach fitting.
16 Jan 2013 (1.0 hours, total time to date: 508.0 hours)
Alex came over to help me get more riveting done on the fin frame. We only had time to attach the forward spar to the root rib. I also cut and formed a 3 x 3 piece of 0.025 aluminum to serve as the right tail cone skin in the area where the fin attach doubler will attach to the crown line. I want to be very careful that the fit is correct, and that I get the attachment holes located correctly.
17 Jan 2013 (2.0 hours, total time to date: 510 hours)
Drilled and dimpled a single attach hole in the skin patch material to fit in the top crown hole at BH160. This served as the starting point to attach it to the structure. I then carefully drilled the other nearby holes from the inside. I then removed it, dimpled the holes, and replaced it on the tail cone. I bolted the external doubler in place using the 3/16 forward fin attach hole, and carefully drilled the same holes through the doubler (also from the inside). Removed the external doubler, drilled two additional #31 pilot attachment holes on the left side of the doubler, and replaced the doubler on the tail cone. I then drilled, de-burred, and dimpled the crown line hole in the internal 0.032 backing plate. I clecoed the backing plate inside the tail cone, and drilled a second attachment hole from the outside (through the external doubler and left tail cone skin). Removed the backing plate & dimpled the second attachment hole. There are 4 attachment holes in the external doubler as well as two holes in the left skin that must be dimpled, and the external doubler will also need to be trimmed before final installation.
18 Jan 2013 (1.0 hour, total time to date: 511 hours)
Removed the external forward fin fitting doubler and dimpled all of the attachment holes in my C-frame. Dimpled the holes in the tail cone left skin using a rivet gun (~<20 psi) with a dimple set. Trimmed the doubler and finished it with a scotch brite wheel. Replaced the doubler, and taped the 0.032 dimpled washers in place inside the crown line (under the fin root rib). These will help protect the tail cone skin dimples since I will be using #4 machine screws to temporarily attach the right tail cone skin while fitting the fin and stabilizer skins.
19 Jan 2013 (1 hour, total time to date: 512 hours)
Replaced the right tail cone skin. Clecoed along the crown line forward of BH160, and used #4 c/s machine screws at the holes with dimpled washers. I also used dimpled washers on the top to protect the skin. Clecoed the BH flanges and lower skin seam line. Installed the forward fin attach external doubler and internal backing plate - clecoed the front & left two fasteners (4). Applied duct tape around the aft crown line to protect the tail cone while fitting the fin skin. Replaced the fin frame in preparation to fit the fin skin.
20 Jan 2013 (3 hours, total time to date: 515 hours)
Cut out, and fit a poster board template for the left & right side of the fin skin along the root rib & tail cone skin interface. Lain out and marked a line in the wall for the projection of the fin C/L to help align the fin. Some twist was needed in the root rib to line up the tip fin rib along the desired fin C/L. I removed the fin root rib, applied some twist, replaced it twice until I was satisfied with the alignment.
Also marked the front spar location at the root rib on the fitting templates & checked the distance from the tail cone skin to the top of the tip fin. Laid out the templates on the fin skin, checked both sides, & determined that there will only be ~ 0.25 inches of excess skin along the fin height - not much room for mistakes. Matched the top of the root rib line on the templates to get an idea of the trimming needed on the skin to fit the tail cone interface. It looks like the left edge will need some slight trimming, but since the root rib is not level (slightly twisted), I will proceed carefully......
Also marked the front spar location at the root rib on the fitting templates & checked the distance from the tail cone skin to the top of the tip fin. Laid out the templates on the fin skin, checked both sides, & determined that there will only be ~ 0.25 inches of excess skin along the fin height - not much room for mistakes. Matched the top of the root rib line on the templates to get an idea of the trimming needed on the skin to fit the tail cone interface. It looks like the left edge will need some slight trimming, but since the root rib is not level (slightly twisted), I will proceed carefully......
21 Jan 2013 (5 hours, total time to date: 520 hours)
Alex came over and helped me to finish riveting the fin frame. As I expected, the most difficult location was the single rivet at the top of the fin spar/tip rib. The rivet would bend immediately at the first hit, and after 4 tries, I decided to oversize it to 5/32, and call it a day.
Replaced the fin frame on the tail cone, and started work to fit the fin skin. I looked for any fitting tips on-line without success, but after proceeding carefully, I came up with a method that seems to work for me. As noted earlier, the skin is provided from MA is pretty close to the final dimensions, so there isn't a lot of room for mistakes. The edges line up very well, so I decided to use the aft and top edges as references (the finished aft edges extend 0.625 past the edge of rear spar flange). I added 0.25 inches on the length at the top for a little "insurance," and measured the length from the top to the tail cone skin interface at 4 locations along each side of the fin frame. I transferred those measurements to the skin to help define the limit of the cut line. The fin skin interface should be pretty close to a straight line (which I found to be true when I fabricated the templates). I also checked it by running an aluminum yard stick around the interface. However, it is important to run/measure a straight line up the length of the fin frame against the edge of the ribs to define the proper intersection with the tail cone skin. I marked the area to notch at the nose of the skin to expose the forward attachment bolt (made it a little small for later trimming). It helps to get that area out of the way so that the "straight" edges will seat well. I used the templates to connect the four points measured along the bottom edge, and made the initial cuts using a cut-off wheel on a die grinder. I kept the cuts inside my fat sharpy line to leave room for sanding and finishing. My initial sanding was done using a Perma-Grit sanding block (it helps to have the longer flat sanding surface). I used a dremmel tool with a 3/16 dia. abrasive rod to round the corners of the nose cut out. I'll go back and finish it more carefully later.
I fabricated two sets of wooden clamps to help hold the skin tightly to the frame using 8 ft of 3/8 thick pine molding stock. I cut 2 pieces ~27 inches, and 2 at ~21 inches, and attached a wood block at the front so I would only need a single clamp in the rear (the clamp at the front of the smaller clamp in the pic is there because of glue at that location). I used a 1.5 thick spacer for the larger clamp and about 1.4 for the smaller one. I also attached some 0.5 thick self-adhesive dense insulating foam to the inside of the clamps to help form the proper curvature of the skin around the frame.
Made the test fit and found some high areas in the middle of my cut along the bottom edge.
Replaced the fin frame on the tail cone, and started work to fit the fin skin. I looked for any fitting tips on-line without success, but after proceeding carefully, I came up with a method that seems to work for me. As noted earlier, the skin is provided from MA is pretty close to the final dimensions, so there isn't a lot of room for mistakes. The edges line up very well, so I decided to use the aft and top edges as references (the finished aft edges extend 0.625 past the edge of rear spar flange). I added 0.25 inches on the length at the top for a little "insurance," and measured the length from the top to the tail cone skin interface at 4 locations along each side of the fin frame. I transferred those measurements to the skin to help define the limit of the cut line. The fin skin interface should be pretty close to a straight line (which I found to be true when I fabricated the templates). I also checked it by running an aluminum yard stick around the interface. However, it is important to run/measure a straight line up the length of the fin frame against the edge of the ribs to define the proper intersection with the tail cone skin. I marked the area to notch at the nose of the skin to expose the forward attachment bolt (made it a little small for later trimming). It helps to get that area out of the way so that the "straight" edges will seat well. I used the templates to connect the four points measured along the bottom edge, and made the initial cuts using a cut-off wheel on a die grinder. I kept the cuts inside my fat sharpy line to leave room for sanding and finishing. My initial sanding was done using a Perma-Grit sanding block (it helps to have the longer flat sanding surface). I used a dremmel tool with a 3/16 dia. abrasive rod to round the corners of the nose cut out. I'll go back and finish it more carefully later.
I fabricated two sets of wooden clamps to help hold the skin tightly to the frame using 8 ft of 3/8 thick pine molding stock. I cut 2 pieces ~27 inches, and 2 at ~21 inches, and attached a wood block at the front so I would only need a single clamp in the rear (the clamp at the front of the smaller clamp in the pic is there because of glue at that location). I used a 1.5 thick spacer for the larger clamp and about 1.4 for the smaller one. I also attached some 0.5 thick self-adhesive dense insulating foam to the inside of the clamps to help form the proper curvature of the skin around the frame.
Made the test fit and found some high areas in the middle of my cut along the bottom edge.
22 Jan 2013 (1 hour, total time to date: 521 hours)
Marked areas to trim, removed the fin skin, and used a 60 grit sanding wheel to trim the bottom edge of the skin. Then, used the Perma-Grit tool to help finish the edge. Did another test fit, and found that the aft end of the left and lower right side will need more trimming.
23 Jan 2013 (2 hours, total time to date: 523 hours)
Marked additional areas to trim, removed and trimmed the skin again as I did previously. Replaced the skin, and the left side looked pretty close, but the right side still needed more. I removed the skin again, and carefully measured the length from the top of the left side along the ribs to the interface with the tail cone at a few points (after trimming, the top edge was nearly flush with the upper rib flange). Transferred the measurements to the right side and trimmed it again. Did another test fit, and it looked good. It looked like I took a little more than I'd planned at the aft end (between BH177.5 & 182), but it will be trimmed away and/or covered with the fairing (very slight difference anyway). I then removed the skin again, used 220, 440, and scotch brite to clean up the edge.
24 Jan 2013 (1 hour, total time to date: 524 hours)
Removed the fin skin, and tightened up the leading edge radius so it will fit more closely to the front fitting and tip rib. I used a piece of carpet to protect the skin, and pressed down with a 2x4. That didn't seem to do much, so I carefully used seaming pliers (with painter's tape to protect the skin). Did a couple of test fits until the fit seemed adequate.
25 Jan 2013 (2 hours, total time to date: 526 hours)
Started work to attach the fin skin to the root rib and front spar.
Ran the desired rivet line along the left and right front spar flange & marked the intersection with the desired attachment point on the root rib flange & the tail cone skin interface. Measured the distance from the tail cone interface to the root rib attach point and fabricated drilling templates to tape along the outside of the fin skin to locate these points (left & Right) when the fin skin was replaced.
Carefully drilled the two #40 pilot attachment holes, removed the fin skin, & checked the hole placement. Looks good!
Ran the desired rivet line along the left and right front spar flange & marked the intersection with the desired attachment point on the root rib flange & the tail cone skin interface. Measured the distance from the tail cone interface to the root rib attach point and fabricated drilling templates to tape along the outside of the fin skin to locate these points (left & Right) when the fin skin was replaced.
Carefully drilled the two #40 pilot attachment holes, removed the fin skin, & checked the hole placement. Looks good!
26 Jan 2013 (4 hours, total time to date: 530 hours)
Justin came over and helped me finish riveting the stabilizer frame. We had 2 miss-steps (my fault) that had to be re-done, but I'm very happy with the final result. Now, I'll put it aside again until I'm finished skinning the fin.
Laid out the skin hole spacing along the front spar using the attachment holes in the root rib and the extension of the rivet line on the fin tip attachment strip. The plans call for a spacing of 3.125, but after checking the available space, I decided to go with a spacing of 2.875 starting approx. 0.75 from the bottom of the spar flange and ending approx. 1.5 from the top of the spar flange. The top location provides 1 inch of internal clearance for riveting.
Fabricated another drilling template with the 2.875 hole spacing. Carefully drilled the #40 pilot holes (working up both sides of the front spar drilling line). I stopped after drilling the first 4 holes on each side, removed the skin, & checked the hole locations. They looked very good, so I replaced the skin & finished drilling the remaining pilot holes along the front spar flange.
Laid out the skin hole spacing along the front spar using the attachment holes in the root rib and the extension of the rivet line on the fin tip attachment strip. The plans call for a spacing of 3.125, but after checking the available space, I decided to go with a spacing of 2.875 starting approx. 0.75 from the bottom of the spar flange and ending approx. 1.5 from the top of the spar flange. The top location provides 1 inch of internal clearance for riveting.
Fabricated another drilling template with the 2.875 hole spacing. Carefully drilled the #40 pilot holes (working up both sides of the front spar drilling line). I stopped after drilling the first 4 holes on each side, removed the skin, & checked the hole locations. They looked very good, so I replaced the skin & finished drilling the remaining pilot holes along the front spar flange.
27 Jan 2013 (1 hour, total time to date: 531 hours)
Started laying out the fastener pattern along the fin root rib. Used the same method used for the first fastener hole on the root rib (drilling template) to position the second fastener hole aft of the front spar. Replaced the skin, drilled #40 pilot holes on the left and right side, removed the skin, & checked the location.
28 Jan 2013 (3 hours, total time to date: 534 hours)
I ran a straight line (using a aluminum yard stick) from the second root rib fastener hole aft along the desired drilling line & taped a piece of poster board on the inside of the rear spar flange to extend the line so that it will be visible when the skin is replaced. Measured the distance from the top edge of the fin tip attach strip to the desired drilling line along the tip rib (aft of the front spar). Drilled the tip rib attachment pilot hole along the front spar line. Fabricated a new drilling template with a spacing of 2.125 for the attachment holes on the root rib (aft of the front spar). Replaced the skin and carefully drilled #40 pilot holes along the aft end of the root rib (checking and making adjustments as necessary by lifting the aft corner of the opposite side). Did the above on both sides of the fin.
Also ran a plumb line along the fin leading edge to verify alignment. Looks very good so far.
Also ran a plumb line along the fin leading edge to verify alignment. Looks very good so far.
29 Jan 2013 (1.5 hours, total time to date: 535.5 hours)
Finished drilling the pilot holes along the root rib (aft of the forward spar). Removed the wood clamps, Used hand clamps at the tip rib, and clamped 2 1x2s along the rear spar flange to hold the trailing edge against the rear spar flange in preparation for drilling the pilot attachment holes along the fin tip rib. Measured and drilled the pilot holes on both sides of the fin tip rib aft of the forward spar.
30 Jan 2013 (1.5 hours, total time to date: 537.0 hours)
Started work drilling the pilot attachment holes along the fin rear spar flange. Measured and determined the rivet spacing (2.032 in my case) between the root and tip rip drilling lines. I decided to start near the center to make it easier to keep the skin nice and flat against the flange as I move along. It all looks very good at this point, but I want to keep it that way. I fabricated another drilling template with the proper spacing., & started drilling the left side 12 3/16 above the root rib drilling line - carefully measuring the location of the hole in the flange to provide a good edge margin. I like to have 0.25 in. distance to the web for bucking purposes, and maintain at least the standard 0.25 in. edge margin.
I worked my way down 3 holes along the left side & drilled the first hole in the right side. I needed to make a slight adjustment in the drilling line to accommodate the 0.125 doubler in the lower end of the spar. I am continually checking the fin alignment using the plumb line. The alignment is pretty well set at this point, but will be established once the rear spar flange holes are completed.
I worked my way down 3 holes along the left side & drilled the first hole in the right side. I needed to make a slight adjustment in the drilling line to accommodate the 0.125 doubler in the lower end of the spar. I am continually checking the fin alignment using the plumb line. The alignment is pretty well set at this point, but will be established once the rear spar flange holes are completed.
31 Jan 2013 (2 hours, total time to date: 539.0 hours)
Continued drilling the attachment pilot holes along the rear fin spar flange. A little slow going because I have been checking and double checking the measurements on the inside and outside of the skin. The flange is approx. 2/32 wider on the left side, and I'd like to keep the drilling line the same distance from the spar web on each side while maintaining the proper edge distance in the flange. I worked my way down to the root rib line on each side.
Also, this has been a record month for me in term of time spent on the project. I wish I could keep up this pace every month....
Also, this has been a record month for me in term of time spent on the project. I wish I could keep up this pace every month....
1 Feb 2013 (1 hour, total time to date: 540.0 hours)
Finished drilling the pilot attachment holes in the rear fin spar flange. Removed the fin tip attachment strip, trimmed the excess at the aft end, & removed the protective plastic. I want to be sure the fit is correct around the nose of the tip rib before drilling the forward fin tip attach holes.
2 Feb 2013 (4 hours, total time to date: 544.0 hours)
Replaced the fin tip attachment strip along the tip rib using the pilot attachment holes aft of the front spar. Measured & marked the location of the tip rib web along the attach strip. Used some duct tape on the inside of the strip to help hold the strip to the tip rib & replaced the fin skin. Transferred the rib web location mark to the fin skin & laid out the location of the attachment holes forward of the front spar. There is very limited space in the nose of the tip rib, so I was careful not to place the most forward attachment hole in a location that would not allow room to install a rivet. I settled on a location 2 inches aft of the nose of the fin tip. This will be very tight for rivet installation, but I should be able to reach it with my squeezer and a no-hole yoke. Fabricated another 2 inch drilling template to position the first hole forward of the front spar. Carefully measured & drilled two pilot attachment holes along the tip rib forward of the front spar on both sides of the fin.
Removed the fin skin again to locate the attachment holes along the root rib forward of the front spar. I decided to use a spacing of 2 inches for the first two holes and 1.5 for the third (leaving approx. 0.75 inches to the forward attach fitting). Marked the location of the first attachment hole on each side & measured the vertical distance from the fin/tail cone skin interface. Replaced the skin, attached the drilling template, double checked the measurement, & drilled these pilot holes. Removed the skin, and repeated this procedure for the next two attachment holes on each side of the fin.
Removed the fin skin again to locate the attachment holes along the root rib forward of the front spar. I decided to use a spacing of 2 inches for the first two holes and 1.5 for the third (leaving approx. 0.75 inches to the forward attach fitting). Marked the location of the first attachment hole on each side & measured the vertical distance from the fin/tail cone skin interface. Replaced the skin, attached the drilling template, double checked the measurement, & drilled these pilot holes. Removed the skin, and repeated this procedure for the next two attachment holes on each side of the fin.
3 Feb 2013 (2.5 hours, total time to date: 546.5 hours)
Measured, marked, & trimmed the fin skin tailing edges using a sanding disk on my die grinder. Marked the area of the fin nose to trim for better access to the forward attach bolt. Removed the skin, cut the nose using a cut-off wheel. Finished the edges & replaced the skin. Removed the entire fin to lay out the rivet locations in the forward steel fitting (to be sure of clearance for rivet installation). Drilled two attachment pilot holes along the fitting on each side - done off of the airframe since the fin is very secure with the skin clecoed in place. Left approx. 1.1 inches between fastener holes for later installation of the nose cover plate. I'll probably drill and tap holes for machine screws.
4 Feb 2013 (1 hour, total time to date: 547.5 hours)
Marked the cuts in the fin skin between BH177.5 & 182. I will leave some skin below the root spar to attach the fairing. I may change my mind later, but can't put it back if I cut it all now. Removed the skin - I also checked to see how difficult it will be to get my arm inside with a bucking bar to instill rivets in one side of the front spar. It looks like it will not be easy, and I don't want to bend the skin. I just may end up using some Cherry Max rivets. Rough cut the skin cut-outs using a cut-off wheel and a hole cutter for the inside radii.
5 Feb 2013 (1.5 hours, total time to date: 549.0 hours)
Finished the fin skin cut-outs using a sanding wheel, 220 sand paper, and a scotch brite wheel. Replaced the skin & started drilling out the pilot holes to final size. I decided to start with #31 and will go back with a sharp #30 bit. Drilled out the holes along each side of the forward spar.
6 Feb 2013 (1 hour, total time to date: 550.0 hours)
Continued drilling out the pilot holes along the fin tip and aft edge. I also drilled out the holes along the fin cut-out, but will drill the remaining holes along the root rib after removing the fin so that I can clamp the flange and skin together.
7 Feb 2013 (2 hours, total time to date: 552.0 hours)
Removed the fin & drilled out the attachment holes along the root rib to #31. Took my time and used hand clamps on each side of the holes to help prevent chip build-up between the layers. Once finished, I decided to drill out all of the holes to 0.125 (almost to #30). The clecos are a bit tight in the #10 holes and the dimpler will expand the holes somewhat & I will probably take the skin off a few more times.
8 Feb 2013 (2 hours, total time to date: 554.0 hours)
Hung the fin on the wall to keep it out of the way while working on the stabilizer skin. The fin must be removed to remove & replace the stabilizer.
Replaced the stabilizer frame & started work to layout & trim the right stab skin along the stab/tail cone interface. I used the same wooden clamps that were used for the fin skin to hold the skin securely around the frame. I placed the skin on the frame & roughly leveled the tip. Made initial measurements (need at least 0.625 beyond the main spar flange, but I started with approx. 0.8 to leave a little room. Made the initial cut line along the bottom edge (~0.4 inches) to allow the top edge to fit closer to the tail cone. Cut the skin using a pneumatic cut-off wheel and used the Perma-Grit sanding block to smooth it out. Replaced the skin to mark it for additional trimming.
Replaced the stabilizer frame & started work to layout & trim the right stab skin along the stab/tail cone interface. I used the same wooden clamps that were used for the fin skin to hold the skin securely around the frame. I placed the skin on the frame & roughly leveled the tip. Made initial measurements (need at least 0.625 beyond the main spar flange, but I started with approx. 0.8 to leave a little room. Made the initial cut line along the bottom edge (~0.4 inches) to allow the top edge to fit closer to the tail cone. Cut the skin using a pneumatic cut-off wheel and used the Perma-Grit sanding block to smooth it out. Replaced the skin to mark it for additional trimming.
9 Feb 2013 (4 hours, total time to date: 558.0 hours)
Continued work trimming, replacing the skin, re-marking, re-trimming, etc.... Each time, the trimming was more refined. I used an angle die grinder with a sanding disk attachment starting with 60 grit and working to 120. Hand sanded each time with #220. I fabricated a tool (piece of 2x4 with 3 inch #10 machine screw clamped to a floor stand) to hold the tip rib at the forward tooling hole. This will help keep the support away from the skin. We'll see how it works out. It's very close to where I want it. Probably one or two more adjustments will be needed.
10 Feb 2013 (3 hours, total time to date: 561.0 hours)
Made some minor adjustments to the right stab skin (mostly trimming the top edge to get a closer fit along the bottom). I got out my laser level and shot a line from the tip of the rear spar to the wall. I'll use that as a line of sight to help verify alignment of the tip rib. I also double checked the rear spar level (looked good). Started laying out the rivet pattern along the top of the frame. The bottom is going to be a challenge (working on my back). I'm going to see how my car ramps work out - otherwise, I'll have to build something.
For fun, I set up a folding chair in front of the tail cone to check out how I'm going to fit in the airplane.
For fun, I set up a folding chair in front of the tail cone to check out how I'm going to fit in the airplane.
11 Feb 2013 (2 hours, total time to date: 563.0 hours)
Well, the car ramps work well enough to get the job done on the bottom side of the stab skin. I laid out the rivet lines along the right root rib & front spar. I taped cardboard strips along the extended rivet lines to allow me to see the end of the lines with the skin on the frame. As I did with the fin, I will use the attachment hole at the intersection of the front spar and root rib lines as my reference hole. I marked the position of the front spar rivet line at the skin/tail cone interface & measured the distance to the reference hole on the top & bottom of the stabilizer. I replaced the skin carefully and double checked the stab to be sure the tip was level (using the sight line). I marked the front spar rivet line on the top & bottom of the skin (fully clamped in place) & drilled the reference pilot holes on each side. I removed the skin and checked the position of the holes in the root rib flange. Looks very good.
12 Feb 2013 (2.5 hours, total time to date: 565.5 hours)
Fabricated a ~0.8 wide strip of scrap 0.032 and drilled pilot holes along a straight drilling line corresponding to the desired hole positions along the right stab root rib. I recently discovered that this is often called a "memory stick" - very appropriate. I used the previously drilled pilot holes on the top and bottom as the reference for the memory stick, and the extended cardboard strips allowed for proper alignment of the stick. Once finished, I attached the memory stick to the root rib, aligned it with the drill line extension, & marked the hole positions on the top and bottom sides. Some holes required adjustment, so I marked these and made the appropriate adjustment to the extended drilling line. I removed the memory stick, replaced the skin (carefully checking the fit and level), clamped it in place, and replaced the memory stick to drill the pilot attachment holes.
13 Feb 2013 (1 hour, total time to date: 566.5 hours)
Removed the skin to check the location of the attachment holes. They look good overall. One came out a little closer to the web than planned, but still has plenty of room (~7/32 from the web). Did some light deburring, and started laying out the rivet pattern for the front spar. The front spar rivet line is approx. 31.5+ between the outside rivets, so I will not fabricate a long "memory stick." Any error would be magnified over the 31 inches. Instead, I've decided to use a mini stick with 3 pilot holes - one as a reference and the other two to position the pilot holes as I move along the rivet line. I will start at the root and work my way up both sides, removing the skin, checking & making any adjustments after each two holes. I'll measure the position of the first hole, and use a spacing of 2.1 in.
14 Feb 2013 (2 hours, total time to date: 568.5 hours)
Re-marked the front spar rivet lines on the spar & measured the location for the first attachment hole at the root end of the spar. Replaced, re-aligned & clamped the skin back in place. I had to check and re-check that the tip was level. This took more time than expected since I was constantly removing & replacing the clamps. Drilled the first attachment pilot holes in the top and bottom front spar. Removed the skin to check the hole locations in the spar flanges. Very slight adjustments are needed wrt to line on the skin. Replaced & aligned the skin. Fabricated the "mini" memory stick with the 2.1 in. spacing. Now, I am ready to drill the next two pilot holes in the top and bottom front spar rivet line.
15 Feb 2013 (1.5 hours, total time to date: 570.0 hours)
Re-checked and leveled the tip rib. Drilled two more pilot attach holes along the top & bottom front spar rivet line using the mini memory stick. Removed the skin, did some light deburring, & checked the hole locations. They look good & the adjustments seem to be holding the drilling lines on the top & bottom spar flanges. Replaced & aligned the skin (again), and drilled two more attachment holes along the top front spar flange.
16 Feb 2013 (5 hours, total time to date: 575.0 hours)
Worked my way up the front spar line on the top and bottom. I removed and replaced the skin one more time after drilling six holes from where I left off yesterday. The holes were tracking very nicely, and I could tell that I could finish the run without removing the skin again.
Got out the laser level and rechecked the tip one more time. My first shot was very good. I also rechecked the distance from the floor to the leading edge of the tip rib so I wouldn't have to set up the laser level again.
Marked the tip rib web and flange lines on the upper skin in preparation to lay out the fastener holes. I used a spacing of 1.75 inches except for the last hole (tip). The tip is very thin, so I used the same position for the last rivet that I used for the fin (same rib geometry) - 2 inches aft of the tip. This should allow me to get the squeezer in there. Drilled out the pilot holes along the upper tip.
Got out the laser level and rechecked the tip one more time. My first shot was very good. I also rechecked the distance from the floor to the leading edge of the tip rib so I wouldn't have to set up the laser level again.
Marked the tip rib web and flange lines on the upper skin in preparation to lay out the fastener holes. I used a spacing of 1.75 inches except for the last hole (tip). The tip is very thin, so I used the same position for the last rivet that I used for the fin (same rib geometry) - 2 inches aft of the tip. This should allow me to get the squeezer in there. Drilled out the pilot holes along the upper tip.
17 Feb 2013 (4 hours, total time to date: 579.0 hours)
Laid out the hole locations along the bottom of the stabilizer tip flange & drilled them out. It took a bit longer since I had to work on my back. I measured and laid out the fastener holes along the stabilizer main spar flange. The spacing worked out to be just under 2 inches (~1 63/64). I fabricated another mini memory stick & drilled out all of the pilot holes along the top. I started work laying out the fastener locations along the bottom. It's now very important to keep checking to be sure the tip rib remains level since it will be "locked-in" once the bottom flange holes are drilled. I've been double checking the height from the floor and the sight-line.
18 Feb 2013 (4 hours, total time to date: 583.0 hours)
Finished laying out the rivet line along the bottom of the stabilizer main spar flange. Fabricated another mini memory stick - the one I used on the top was well worn. Worked my way along the bottom edge, drilling the pilot attachment holes, checking the location, making any needed adjustments, etc. Again, it definitely takes more time doing this on your back. Finished drilling the pilot holes and installed a 2x4 from floor to ceiling to help support the left stabilizer tip rib. I was very limited on the right side, and the stand was a pain-in-the-a**.
19 Feb 2013 (1 hour, total time to date: 584.0 hours)
Used my laser level to obtain a line of sight to the wall for the left stab tip, also checked the level distance from the floor at both ends of the tip rib. While I had the level out, I also checked the alignment of the elevator hinge brackets. A level laser shot went right through all three bolt holes in the brackets. It wasn't "perfectly" centered in each hole, but very close. The beam went cleanly through all three holes, and the laser was approx. 26 inches from the nearest bracket. Not too shabby :-)
Attached the tip rib support to the vertical 2x4 to hold it in position, and began work fitting the left stab skin.
Attached the tip rib support to the vertical 2x4 to hold it in position, and began work fitting the left stab skin.
20 Feb 2013 (2 hours, total time to date: 586.0 hours)
Trimmed the root end of the left stabilizer skin to fit the tail cone skin interface. I marked and trimmed the lower side first using a cut-off wheel on my die grinder and angle grinder w/sanding disks (as I did on the other skins). Replaced the skin, measured, marked, and repeated the process several times. I checked and double checked the alignment to match the root and tip length of the right side. When I was nearly finished, I cut/sanded the bolt access notch at the root tip. Also, used my seaming pliers to tighten up the nose radius along the span so the skin will seat well around the root & tip ribs (as was done on the other skins).
21 Feb 2013 (1 hour, total time to date: 587.0 hours)
Removed the skin & did a little more light sanding to adjust the fit. I measured and marked the fastener drilling lines along the front spar and root rib flanges. Attached tabs to extend the lines beyond the skin (just as I did on the other skins to locate the lines on the skin). Added a layer of duct tape along the skin interface to protect the tail cone skin. Replaced the skin & marked the interface with a Sharpy. The skin needs a little more adjustment along the bottom edge.
22 Feb 2013 (4.5 hours, total time to date: 591.5 hours)
Removed the skin & made more adjustments to the fit using an 80 grit sanding disk and finishing by hand with 120, 220, and a scotch brite pad. Also did a little more finishing on the bolt access notch.
Marked the intersection of the front spar drilling line and the skin/tail cone interface as a reference once the skin is replaced. Measured the distance from the tail cone interface to the skin attachment hole on the root rib (at the front spar line). This hole will be the reference hole for the root rib & front spar. Replaced the skin, clamped it in place, and drilled the reference pilot attachment holes in the top & bottom of the skin. Removed the skin & checked the location of the holes. The top was "dead-on" and the bottom was about 1/32 closer to the web.
Using the same "memory stick" that I used for the right root rib, I clecoed the stick to the reference hole & marked the locations of the attachment holes in the left root rib (top & bottom). Noted any necessary adjustments on the stick and the extended tab reference. Replaced the skin & carefully drilled the top & bottom root rib pilot attachment holes. Removed the skin to check these holes - looked very good. Measured the location of the first attachment hole along the front spar (top & bottom). Replaced the skin & drilled these #40 pilot holes.
Marked the intersection of the front spar drilling line and the skin/tail cone interface as a reference once the skin is replaced. Measured the distance from the tail cone interface to the skin attachment hole on the root rib (at the front spar line). This hole will be the reference hole for the root rib & front spar. Replaced the skin, clamped it in place, and drilled the reference pilot attachment holes in the top & bottom of the skin. Removed the skin & checked the location of the holes. The top was "dead-on" and the bottom was about 1/32 closer to the web.
Using the same "memory stick" that I used for the right root rib, I clecoed the stick to the reference hole & marked the locations of the attachment holes in the left root rib (top & bottom). Noted any necessary adjustments on the stick and the extended tab reference. Replaced the skin & carefully drilled the top & bottom root rib pilot attachment holes. Removed the skin to check these holes - looked very good. Measured the location of the first attachment hole along the front spar (top & bottom). Replaced the skin & drilled these #40 pilot holes.
23 Feb 2013 (3.5 hours, total time to date: 595.0 hours)
Fabricated a new memory stick with a hole spacing of 2.1 in. (same as the right side) along the front spar line. This time, I made it one hole longer (4 total, vs. 3). The holes get worn, so adding an extra hole will help it last longer over the 30 holes that need to be drilled along the top and bottom.
Attached the memory stick to the reference hole & drilled the first 3 #40 attachment holes in the top & bottom of the skin. Removed the skin to check the hole location & noted any required adjustment. The top looked nearly dead-on, but the bottom was off about 1/4 - 1/2 of the sharpy line width. Replaced and clamped the skin back in place with all of the holes clecoed, & repeated the process for the next 3 holes. The spacing for the last hole in the line was slightly less than 2.1, so I measured the distance from the previous hole to the desired location (~5/16 from the end of the spar flange), replaced the skin, taped a drilling template in place, & drilled the final pilot hole in the line.
Attached the memory stick to the reference hole & drilled the first 3 #40 attachment holes in the top & bottom of the skin. Removed the skin to check the hole location & noted any required adjustment. The top looked nearly dead-on, but the bottom was off about 1/4 - 1/2 of the sharpy line width. Replaced and clamped the skin back in place with all of the holes clecoed, & repeated the process for the next 3 holes. The spacing for the last hole in the line was slightly less than 2.1, so I measured the distance from the previous hole to the desired location (~5/16 from the end of the spar flange), replaced the skin, taped a drilling template in place, & drilled the final pilot hole in the line.
24 Feb 2013 (4 hours, total time to date: 599 hours)
Removed the skin & measured the distance from the last attach hole at the tip of the front spar line to the desired hole location on the tip rib (top & bottom). I decided to use this as a reference hole for another memory stick for the attach holes along the tip rib (it turned out not to save any more time over measuring from the edge, but I think it worked out a little more accurately). Fabricated two drilling templates between the last spar hole and the tip rib reference holes. Laid out the hole spacing for the tip rib and fabricated the memory stick.
Replaced the skin & drilled out the two reference holes. Removed the chord wise wooden clamps and clamped 1x2s along the rear spar. Removed the tip support, used the laser level to triple check the tip rib, marked a point on the tip, & measured the position from the floor (also found a level point on the aft top skin as another reference). Replaced the tip support & screwed it in place (again).
Removed the skin (yes, again...) and clecoed the new memory stick to the tip rib reference hole. Taped poster board tabs along the extended tip rib drilling lines (tip and bottom), Marked the attach hole positions from the memory stick, made any notes on the stick for adjustment, and marked the appropriate alignment marks on the tabs. Replaced the skin & drilled out the tip rib pilot holes.
Measured and marked the aft edge of the rear spar flange (top and bottom) on the skin. Fabricated another mini memory stick (4 holes) with a hole spacing of a "hair" under 2 inches (to work out evenly along the flange line - just like the right side). This time, I made the stick 17/32 wide to give me just over 1/4 inch edge margin for the spar flange and allow me to line up the edge of the stick with the single line along the aft edge of the spar flange (to save a little time). Started drilling the pilot holes along the top & bottom rear spar flange.
Replaced the skin & drilled out the two reference holes. Removed the chord wise wooden clamps and clamped 1x2s along the rear spar. Removed the tip support, used the laser level to triple check the tip rib, marked a point on the tip, & measured the position from the floor (also found a level point on the aft top skin as another reference). Replaced the tip support & screwed it in place (again).
Removed the skin (yes, again...) and clecoed the new memory stick to the tip rib reference hole. Taped poster board tabs along the extended tip rib drilling lines (tip and bottom), Marked the attach hole positions from the memory stick, made any notes on the stick for adjustment, and marked the appropriate alignment marks on the tabs. Replaced the skin & drilled out the tip rib pilot holes.
Measured and marked the aft edge of the rear spar flange (top and bottom) on the skin. Fabricated another mini memory stick (4 holes) with a hole spacing of a "hair" under 2 inches (to work out evenly along the flange line - just like the right side). This time, I made the stick 17/32 wide to give me just over 1/4 inch edge margin for the spar flange and allow me to line up the edge of the stick with the single line along the aft edge of the spar flange (to save a little time). Started drilling the pilot holes along the top & bottom rear spar flange.
25 Feb 2013 (2 hours, total time to date: 601.0 hours)
Finished drilling the pilot attachment holes along the rear spar line!
I needed to make a new memory stick at the 1/2 way point (it was getting fairly worn out). I duplicated the old one, so it didn't take quite so long. Also, checked the level after each 3 holes (on both sides) . Now that it's done, the alignment looks great. I replaced the fin to get a nice photo.
I still need to do some trimming and enlarge the holes, etc., but will switch to the fin and get it ready for riveting.
I needed to make a new memory stick at the 1/2 way point (it was getting fairly worn out). I duplicated the old one, so it didn't take quite so long. Also, checked the level after each 3 holes (on both sides) . Now that it's done, the alignment looks great. I replaced the fin to get a nice photo.
I still need to do some trimming and enlarge the holes, etc., but will switch to the fin and get it ready for riveting.
26 Feb 2013 (2 hours, total time to date: 603.0 hours)
Removed the fin skin & tip attach strip. Replaced the skin without the attach strip to see if the holes would still line up in case I need to change the attachment method for the fiberglass tips. It looked fine, but I found that the tips are approx. 0.045 thick (thicker than the 0.032 skin, but thinner than the combination of the skin/rib (0.064). I asked Brian Kelly for his opinion (He's building an RV-8), and he suggested attaching as planned with blind rivets and lightly sanding the gel coat to fit. I was going to make the tips removable, but as Brian said, there is nothing to inspect. If it is damaged in the future, I can always drill out the blind rivets.
I removed the plastic protective cover from the skin and fin front spar, deburred the fastener holes in the fin skin & the fin ribs/spars, and used 220 sand paper & scotch brite to prepare the skin/ribs dimpling/assembly.
I removed the plastic protective cover from the skin and fin front spar, deburred the fastener holes in the fin skin & the fin ribs/spars, and used 220 sand paper & scotch brite to prepare the skin/ribs dimpling/assembly.
27 Feb 2013 (2 hours, total time to date: 605.0 hours)
Dimpled the attachment holes in the fin skin. tip rib, front, & rear spar. I was able to use the c-frame to dimple most of the holes in the skin (with help from Beth). Using the rivet squeezer with the dimple dies worked very well on the front and rear spar flanges. The vice grip dimpler was needed to get into the tight spots.
It looks like I will be able to install a floating nut plate at the bottom of the skin at the rear spar flange as the top rear attach point for the fairing covering the elevator push rod & rudder cables.
It looks like I will be able to install a floating nut plate at the bottom of the skin at the rear spar flange as the top rear attach point for the fairing covering the elevator push rod & rudder cables.
28 Feb 2013 (1 hour, total time to date: 606.0 hours)
Removed the fin frame & dimpled the attachment holes in the fin root rib. Also fabricated aluminum shims to fill the gaps in the fit between the forward steel attach fitting and the root rib flange. I mixed some T-88 epoxy and tested it on some scrap aluminum to see if it will properly bond the shims. It will set overnight, and I'll wait to install the shims.
1 Mar 2013 (2.5 hours, total time to date: 608.5 hours)
The epoxy seemed to work very well on the aluminum, so I finished fitting the 0.025 shims to fill the gap between the steel fitting and the fin root rib. The gap resulted from the adjustment required to center the attachment hole in the flange of fuselage BH160. Applied the epoxy to the shims, inserted them in the gap, & used small c-clamps to hold each side in place while curing.
Started drilling out the attachment holes in the stabilizer skin to final size. I've been using a 1/8 inch bit since the dimpling process enlarges the holes. I finished the top of the left side as well as the top root rib on the right side. I will need to order more clecos.
Finally, I decided to prime the mating surfaces of the fin skin & frame since the weather will be turning colder again tomorrow. I cleaned the areas with a de-greaser and used a self-etching primer.
Started drilling out the attachment holes in the stabilizer skin to final size. I've been using a 1/8 inch bit since the dimpling process enlarges the holes. I finished the top of the left side as well as the top root rib on the right side. I will need to order more clecos.
Finally, I decided to prime the mating surfaces of the fin skin & frame since the weather will be turning colder again tomorrow. I cleaned the areas with a de-greaser and used a self-etching primer.
2 Mar 2013 (3 hours, total time to date: 611.5 hours)
Drilled out the attachment holes through the bonded shims at the fin forward attach fitting. De-burred the holes & countersunk the holes in the root rib flange. Then, I de-greased, primed the area, & replaced the fin frame on the tail cone.
Replaced the fin skin & fin tip attachment strip. In anticipation of the attachment requirement of the aft tail cone fairing, I trimmed the fin skin to leave approx. 1.5 inches below the root rib rivet line for installation of a nut plate. The fairing will overlap the fin skin, so this upper aft fairing nut plate needs to attach through the skin and rear spar flange. I decided to use #8 c/s machine screws for fairings that need to be removed for annual inspections.
Replaced the fin skin & fin tip attachment strip. In anticipation of the attachment requirement of the aft tail cone fairing, I trimmed the fin skin to leave approx. 1.5 inches below the root rib rivet line for installation of a nut plate. The fairing will overlap the fin skin, so this upper aft fairing nut plate needs to attach through the skin and rear spar flange. I decided to use #8 c/s machine screws for fairings that need to be removed for annual inspections.
Measured, drilled & fit the nut plate attachment holes. Removed the fin skin to dimple the holes (#19 & #40 nut plate attach holes). Dimpled the holes in the rear spar flange using dimple dies in my hand squeezer (note, I had to grind down the female die O.D. to fit inside the rear spar - I kept the edge distance at 0.32). De-greased & primed the mating surfaces of the skin & rear spar.
3 Mar 2013 (4.5 hours, total time to date: 616.0 hours)
Replaced the skin on the fin (hopefully for the last time), and prepared to begin the process of riveting it to the frame. The procedure recommended in the construction documentation from Mustang Aeronautics is to rivet one side of the fin along the rear spar, root. & tip ribs. Then, rivet the root & tip ribs (forward of the front spar) on the other side. The clecos on the "other" side can then be removed to allow access to the inside to rivet the front spar.
I started with the root & tip ribs because I was very curious about how difficult it would be to buck the rivets in the nose of each - especially the tip rib since it is so narrow. Well, it was a bit of a challenge for me and I had to drill out 2 rivets (not all that bad, considering...). I was able to use a 0.75 thick tungsten bucking bar for nearly all of the root rib (except the two in the forward fitting). Actually, I started the second one aft with my hand squeezer, and finished it with a 0.5 inch thick bar. For the tip rib, the 0.5 bar worked well for most of the rivets, but I had to remove the opposing cleco. The last two at the tip were done with the squeezer - note: I bought a 4 inch, no hole yoke which fits in these areas.
I started with the root & tip ribs because I was very curious about how difficult it would be to buck the rivets in the nose of each - especially the tip rib since it is so narrow. Well, it was a bit of a challenge for me and I had to drill out 2 rivets (not all that bad, considering...). I was able to use a 0.75 thick tungsten bucking bar for nearly all of the root rib (except the two in the forward fitting). Actually, I started the second one aft with my hand squeezer, and finished it with a 0.5 inch thick bar. For the tip rib, the 0.5 bar worked well for most of the rivets, but I had to remove the opposing cleco. The last two at the tip were done with the squeezer - note: I bought a 4 inch, no hole yoke which fits in these areas.
4 Mar 2013 (2.5 hours, total time to date: 618.5 hours)
Riveted the holes along the rear spar. Although I had plenty of tape on the bucking bar, it is difficult to avoid scratching the spar since the tape wears very quickly. I had some scrap 1/8 thick rubber, so I taped a piece to the bucking bar to help protect the spar . It leaves a "skid mark," but that is easier to remove.
I also had a few more drill-outs, and one case where I had to oversize a hole after 2 drill-outs. I'll have to come back to this later.......
I also had a few more drill-outs, and one case where I had to oversize a hole after 2 drill-outs. I'll have to come back to this later.......
5 Mar 2013 (2 hours, total time to date: 620.5 hours)
Fabricated a small coupon to simulate the rear spar flange/skin interface with two fastener holes. Drilled the holes to #30, de-burred, and dimpled the holes. I then drilled out one hole to #21 to match the "oops" hole I have to deal with on the fin. I can order some NAS1097-5 smaller head c/s rivets, but I'd rather have a little more contact area and use a "standard" AN426AD5 replacement. The question was whether or not I would be able to re-dimple the hole to accept the AN426 rivet. I was able to re-dimple the hole using my hand squeezer with some elbow grease. I ordered some larger c/s rivets and a re-built pneumatic squeezer (working with the hand squeezer convinced me that I should be using a pneumatic one - see below).
I set the rivets on the other side of the fin along the tip and root ribs (in front of the front spar). I had to use my hand squeezer for the rivets in the nose of each rib. I got in the habit of starting to set the rivet and checking the head to be sure in was flush (guess how I figured that out?...). My 4.5 inch no hole yoke has been essential in these areas, but it is very hard to keep the rivet set flat on the rivet when you are squeezing your head off at the other end. When I did the other side, I had enough room to finish with the gun and bucking bar. The last thing I wanted to do was damage the shop heads on the other side. I had to drill one the forward root rib rivet because it did not set correctly. I used the gun where I could, but it has been difficult to get the shop heads nice and flat - especially in the tighter, curved areas. I'm satisfied that mine are good enough, but it has been very time consuming. If anyone reading this is debating the cost/benefit of the hand vs pneumatic squeezer, I can tell you this:
Over the course of building an airplane, you will be setting a lot of rivets along an accessible edge. The problem I have with the hand squeezer is that it is difficult to hold steady/level on the rivet head, and it is very easy to lift the head when squeezing. You have to get the full leverage at the handles, and hold the head in place at the same time. A good hand squeezer will cost about $200 and the yokes are $125 - 175. Yes, the pneumatic ones are about $600 (with a yoke), so the question is whether it's worth about $250 more. I lucked out and found a rebuilt body for $325 (the yokes are interchangeable), but I've already been regretting spending $200 on the hand squeezer.
I set the rivets on the other side of the fin along the tip and root ribs (in front of the front spar). I had to use my hand squeezer for the rivets in the nose of each rib. I got in the habit of starting to set the rivet and checking the head to be sure in was flush (guess how I figured that out?...). My 4.5 inch no hole yoke has been essential in these areas, but it is very hard to keep the rivet set flat on the rivet when you are squeezing your head off at the other end. When I did the other side, I had enough room to finish with the gun and bucking bar. The last thing I wanted to do was damage the shop heads on the other side. I had to drill one the forward root rib rivet because it did not set correctly. I used the gun where I could, but it has been difficult to get the shop heads nice and flat - especially in the tighter, curved areas. I'm satisfied that mine are good enough, but it has been very time consuming. If anyone reading this is debating the cost/benefit of the hand vs pneumatic squeezer, I can tell you this:
Over the course of building an airplane, you will be setting a lot of rivets along an accessible edge. The problem I have with the hand squeezer is that it is difficult to hold steady/level on the rivet head, and it is very easy to lift the head when squeezing. You have to get the full leverage at the handles, and hold the head in place at the same time. A good hand squeezer will cost about $200 and the yokes are $125 - 175. Yes, the pneumatic ones are about $600 (with a yoke), so the question is whether it's worth about $250 more. I lucked out and found a rebuilt body for $325 (the yokes are interchangeable), but I've already been regretting spending $200 on the hand squeezer.
6 Mar 2013 (2.5 hours, total time to date: 623.0 hours)
Removed the stabilizer from the tail cone to drill out the bottom attach holes to 0.125 (I'd rather not have to do this on my back again). Replaced the fin on the tail cone (will come back to it later).
Fabricated two wooden stands from 1x4s to support the stabilizer on my work bench. Started drilling out the bottom attachment holes. Just a few more to go....
Fabricated two wooden stands from 1x4s to support the stabilizer on my work bench. Started drilling out the bottom attachment holes. Just a few more to go....
7 Mar 2013 (1 hour, total time to date: 624.0 hours)
I fabricated a fixture to hold the stabilizer root rib in place like it will be on the tail cone. Without it, the stabilizer is very flexible about the vertical axis. It will be much easier to work on the bench if the stabilizer can be rotated and moved without worrying about damaging (bending) the spar. I fabricated two angle brackets from 0.05 sheet, match drilled the 3/16 attach holes, drilled holes to attach the brackets with wood screws to a 8.25 inch 2x2, aligned the spar, marked the hole positions on the 2x2, dimpled the attach holes for the wood screws in the brackets, and attached the brackets to the 2x2s. I primed the mating surfaces of the brackets to the stabilizer and will install the fixture when the primer dries.
8 Mar 2013 (3 hours, total time to date: 627.0 hours)
Finished drilling out the stabilizer skin attach holes to 0.125. Measured/marked the skin tips & trailing edges for trimming. Removed the left side skin, did some light de-burring, and used a cut-off wheel to do the initial trim cuts. Then, I moved on to sanding disks, and finer sand paper. Cut out & formed a tip attach strip from some scrap 0.025 to sandwich between the skin and the tip rib to be used to attach the fiberglass stabilizer tips.
9 Mar 2013 (4 hours, total time to date: 631.0 hours)
Positioned the tip attach strip on the outside of the left tip rib. Replaced the left skin & carefully match-drilled the 0.125 attach holes through the strip - using the existing holes in the skin as a guide. It is very helpful to use the reflection of the drill bit in the skin to align the bit normal to the surface of the skin.
Removed the right side skin, did some light de-burring, and used a cut-off wheel to do the initial trim cuts along the tip & aft of the rear spar flange. Then, I moved on to sanding disks, and finer sand paper. Cut out & formed a tip attach strip from some scrap 0.025 to sandwich between the skin and the tip rib to be used to attach the fiberglass stabilizer tips. Positioned the tip attach strip on the outside of the right tip rib. Replaced the right skin & carefully match-drilled the 0.125 attach holes through the strip (as I did on the other side).
Removed the right side skin, did some light de-burring, and used a cut-off wheel to do the initial trim cuts along the tip & aft of the rear spar flange. Then, I moved on to sanding disks, and finer sand paper. Cut out & formed a tip attach strip from some scrap 0.025 to sandwich between the skin and the tip rib to be used to attach the fiberglass stabilizer tips. Positioned the tip attach strip on the outside of the right tip rib. Replaced the right skin & carefully match-drilled the 0.125 attach holes through the strip (as I did on the other side).
10 Mar 2013 (1 hour, total time to date: 632.0 hours)
Fabricated a 3-hole test coupon to practice installing Cherry Max rivets. It will be much easier to use Cherry Max rivets along the front spar in the horizontal stabilizer and the fin. It would be a good idea to install a few practice rivets first. Also, I measured and drilled #40 pilot attachment holes in the bottom stabilizer root rib attachment fittings.
13 Mar 2013 (2 hours, total time to date: 634.0 hours)
Drilled #40 pilot attachment holes in the top stabilizer root rib attachment fittings. Then, drilled the forward root rib attachment fittings out to 0.125 in.
Installed a 3212-4-2 Cherry Max rivet in the test coupon successfully, then installed them along the left side of the fin forward spar.
Removed the fin & replaced the horizontal stabilizer on the tail cone. Then, replaced the fin on the tail cone.
I am having shoulder surgery tomorrow and will not be able to work on the airplane for an unknown period of time. I'm hoping it will be less than 6 weeks.
Installed a 3212-4-2 Cherry Max rivet in the test coupon successfully, then installed them along the left side of the fin forward spar.
Removed the fin & replaced the horizontal stabilizer on the tail cone. Then, replaced the fin on the tail cone.
I am having shoulder surgery tomorrow and will not be able to work on the airplane for an unknown period of time. I'm hoping it will be less than 6 weeks.
13 Apr 2013 (2.5 hours, total time to date: 636.5 hours)
Well, I'm back. Trying to ease back into working on the airplane. I can't lift my right arm, but can bend it at the elbow and do light work on the bench.
Starting working on the rudder. Measured, marked, and trimmed the stiffeners so that they will not interfere with the skin when formed to final shape & attached to the spar. I trimmed and finished each pair to be match (not mirror image) so the flanges would fall on either side of the rivet line (not touch). The pilot holes are #41 & I will dimple them for -3 flush rivets.
Temporarily attached the rudder spar to the fin spar hinge fittings & marked the extended upper fin skin line for later trimming.
Starting working on the rudder. Measured, marked, and trimmed the stiffeners so that they will not interfere with the skin when formed to final shape & attached to the spar. I trimmed and finished each pair to be match (not mirror image) so the flanges would fall on either side of the rivet line (not touch). The pilot holes are #41 & I will dimple them for -3 flush rivets.
Temporarily attached the rudder spar to the fin spar hinge fittings & marked the extended upper fin skin line for later trimming.
20 Apr 2013 (2.5 hours, total time to date: 639.0 hours)
Started fitting the skin stiffeners to the elevators. Since I still can't lift my right arm, I will do as much prep work as possible until I can start riveting again. I measured, trimmed, & clecoed the stiffeners to the skins.
I also checked to be sure that the fiberglass fin and rudder tips line up along the skin/tip interface assuming a straight line through the fin and rudder. They do, so I will trim the upper rudder spar & skin to align with the fin.
I also checked to be sure that the fiberglass fin and rudder tips line up along the skin/tip interface assuming a straight line through the fin and rudder. They do, so I will trim the upper rudder spar & skin to align with the fin.
21 Apr 2013 (1.5 hours, total time to date: 640.5 hours)
Finished fitting the skin stiffeners for the elevator. Started work building wood stands to hold the control surfaces when riveting the stiffeners in place.
23 April 2013 (0.5 hours, total time to date: 641.0 hours)
Glued and screwed the base and vertical 1x4 pieces for both wood stands.
24 Apr 2013 (0.5 hours, total time to date: 641.5 hours)
Attached the diagonal supports for the wood stands. These will be very helpful when riveting all of the skin stiffeners for the MM control surfaces.
27 Apr 2013 (2 hours, total time to date: 643.5 hours)
De-burred, finished, and dimpled the rudder skin stiffeners.
28 Apr 2013 (1.5 hours, total time to date: 645.0 hours)
De-burred the rudder skin attachment holes, and started dimpling the holes. Approx. 2/3 of the rudder skin holes have been dimpled.
Work is still progressing more slowly than I'd like because of my right shoulder recovery process.
Work is still progressing more slowly than I'd like because of my right shoulder recovery process.
29 Apr 2013 (1 hour, total time to date: 646.0 hours)
Finished dimpling the rudder skin stiffener attachment holes, re-assembled the rudder skin/stiffeners with clecos,and began work de-burring, finishing, and dimpling the elevator skin stiffeners.
For anyone who will be dimpling control surface skin stiffener holes like these using a C-frame, I highly recommend using a scrap piece of 1x4 (or similar) to hold the skin flat against the C-frame table. I learned the hard way when I ended up with a "ding" along the outside edge of the female dimple die at one of my holes. I should be able to fix it with my flush rivet set when I rivet the stiffener. It takes 2 people to hold the skin away from the C-frame and dimple as you approach the trailing edge. The skin will tend to pull up from the table because of the amount of flexing required to reach these holes.
For anyone who will be dimpling control surface skin stiffener holes like these using a C-frame, I highly recommend using a scrap piece of 1x4 (or similar) to hold the skin flat against the C-frame table. I learned the hard way when I ended up with a "ding" along the outside edge of the female dimple die at one of my holes. I should be able to fix it with my flush rivet set when I rivet the stiffener. It takes 2 people to hold the skin away from the C-frame and dimple as you approach the trailing edge. The skin will tend to pull up from the table because of the amount of flexing required to reach these holes.
30 Apr 2013 ( 1 hour, total time to date: 647.0 hours)
De-burred, finished, and dimpled the skin stiffeners for the left elevator.
1 May 2013 (0.5 hour, total time to date: 647.5 hours)
Laid out and marked the left elevator skin cut-out for the elevator trim tab.
2 May 2013 (1 hour, total time to date: 648.5 hours)
Double-checked the elevator skin trim tab cut-out dimensions as shown in the trim tab drawing. Marked & progressively drilled out the inside corners (on each side) to 1/4 in. for local stress relief. Then used my die grinder with a cut-off wheel to "rough cut" the skin Just short of the edge of the cut lines.
These rough cuts need to be done carefully and not rushed. I'm always relieved when I get them done without incident - as was the case here.
These rough cuts need to be done carefully and not rushed. I'm always relieved when I get them done without incident - as was the case here.
3 May 2013 (1.5 hours, total time to date: 650.0 hours)
Began work finishing the left elevator skin. I used a 1/4 in. dremmel drum sanding tool to finish the corner radii for the trim tab & a 120 grit sanding disk (die grinder) to dress the rough edge cuts to the cut line. Finally, finished the trim tab cut-out edges using fine sand paper, scotch brite pads, and steel wool.
4 May 2013 (1 hour, total time to date: 651.0 hours)
Removed the protective plastic from the left elevator skin, de-burred, & dimpled the skin stiffener attachment holes. Beth was a big help providing a second set of hands to hole the skin away from the C-frame dimpler. Clecoed the skin stiffeners back in place.
5 May 2013 (4 hours, total time to date: 655.0 hours)
Laid out & drilled two, #41 skin stiffener attachment holes along the inboard right elevator skin/stiffener. These holes were missing because they are not used in the left elevator (due to the trim tab cut-out). Removed the protective skin from the right elevator skin, de-burred, & dimpled the skin stiffener attachment holes (again, with help from Beth). De-burred, finished, & dimpled the right elevator skin stiffeners. Clecoed the stiffeners back in place.
Returned to the left elevator skin and made a few minor adjustments to the skin stiffeners to be sure of clearance when the skins are closed. Measured, cut & finished the aft section of the left inboard elevator skin stiffeners where the trim tab will be installed. I left approximately 0.5 inch aft of the aft attachment hole since I will use T-88 epoxy to provide additional stiffener effectiveness. This also provides plenty of clearance for the trim tab hinge spar.
Returned to the left elevator skin and made a few minor adjustments to the skin stiffeners to be sure of clearance when the skins are closed. Measured, cut & finished the aft section of the left inboard elevator skin stiffeners where the trim tab will be installed. I left approximately 0.5 inch aft of the aft attachment hole since I will use T-88 epoxy to provide additional stiffener effectiveness. This also provides plenty of clearance for the trim tab hinge spar.
6 May 2013 (1 hour, total time to date: 656.0 hours)
While waiting for my shoulder to recover enough to use my rivet gun, it's a good time to return to work on the fin. I used a step stool to reach the upper skin attach holes along the right side of the fin. I pulled the remaining Cherry Max rivets along the front spar. Then, I removed the rudder spar, cut, and finished the top as marked along the extended upper fin skin line.
7 May 2013 (1.5 hours, total time to date: 657.5 hours)
Removed the fin from the tail cone & installed a -5 flush rivet in a skin attach hole along the rear spar where I had some difficulty squeezing several -4 rivets (see Mar 4, 2013). As a result, I had no choice but to oversize the hole. I had some trouble re-dimpling the hole for a -5 rivet because of the thickness of the spar & skin, but managed to get it slightly larger. I could not find any -5 oops rivets for a reasonable price, so I modified a standard -5 by shaving the head and reducing the diameter using a scotch brite wheel to fit in the new dimple. It took a few tries, but I did a decent job. It's still a little larger than the -4's, but not very noticeable.
I ordered a rebuilt pneumatic squeezer & used it to set the rivet. Wow!, what a difference! Another tip for anyone interested - buy a pneumatic squeezer.
I ordered a rebuilt pneumatic squeezer & used it to set the rivet. Wow!, what a difference! Another tip for anyone interested - buy a pneumatic squeezer.
8 May 2013 (2 hours, total time to date: 659.5 hours)
Used my (new) pneumatic squeezer to install the remaining rivets on the right side of the fin (everything aft of the front spar line). It really worked well - consistent shop heads (once adjusted) and was much faster. The only snag I ran into was from my lack of experience using the tool. Along the lower portion of the rear spar, the rivet holes are a little closer to the 0.125 doubler than they are from the inside edge everywhere else. I didn't catch on at first to what was happening, but as the shop heads were being formed, they expanded beyond the edge of the yoke and ruined the head. I didn't keep the yoke far enough in the channel. The first time, I thought the rivet was age hardened (since, the problem could never be my own fault - hehehe). Then, I used a newer rivet and got the same result. Then, I went to the next hole, and you guessed it, I did it again. After drilling out 3 rivets, I finally figured out was was going on. The good news for me was that I did a good job of getting them out. I have been using a #31 bit to get them out, and it helps keep the hole from being damaged by drill operator error. If you get the hole centered, all you need to do is grab the shop head with pliers and twist them off. After that little adventure, everything went pretty smoothly. In the end, what worked best for me was to position the flush set on the rivet head, slowly engage the trigger to close the gap (watching the flat set to keep it FLAT on the skin, and let the weight of the squeezer + maybe a little elbow grease hold the head flush), watch the shop head side for edge clearance, and drive it home.
9 May 2013 (1.5 hours, total time to date: 661.0 hours)
Removed the stabilizer to prepare it for riveting, then replaced the fin on the tail cone (a good place to keep it safe, and it will be easier to fabricate the aft fairings with the stabilizer removed).
Removed the left stab skin and it's plastic cover. De-burred the rivet holes and lightly finished the edges of the skin. The aft edges will be trimmed one more time after fitting the elevator.
Removed the left stab skin and it's plastic cover. De-burred the rivet holes and lightly finished the edges of the skin. The aft edges will be trimmed one more time after fitting the elevator.
10 May 2013 (1 hour, total time to date: 662.0 hours)
Started dimpling the left stabilizer skin and had another "little" incident. This was a good one....
I like to use the C-frame table as much as possible since it produces nicely formed dimples and is relatively fast. In the case of formed skins, it takes an extra pair of hands to put one side away from the C-frame. As I found out a while back with the control surfaces, it helps to use a scrap piece of wood to hold the skin against the table. Well, in this case, the skin is thicker and wants to lift up a lot more. As I was moving along the front frame rivet line, the skin slipped off of the male dimple die, and when I struck the shaft, I knew right away that I had a big problem. Yep, I punched a new hole in the skin right next to the intended target. This is another one of my mistakes that I don't wish on anyone else.
I did all I could to flatten it back out using the flush set on my rivet gun and a bucking bar, and dimpled the correct hole. However, it was a lost cause because the skin cracked when I flattened the mistake - actually, it was a futile attempt anyway since the hole was so close and another crack immediately formed between the two holes. Almost funny given my day job.... Anyway, after thinking it over and having a discussion with a good buddy (Tom Dieter's), I'll be cutting out the damage and fabricating a repair patch with a filler inside the cut-out. Boy, this was a day I wish I could do-over.
Also, for what it may be worth, I've found that when this kind of thing happens it's better to stop and let things sit a while. Very hard to do, and I didn't exactly follow that advise as much as I should have - although flattening the skin made me feel like I was doing something at the time. The situation doesn't seem as bad today as it did yesterday. It's fixable, and I'm grateful that it was on the bottom surface. :-) Moving on.....
I like to use the C-frame table as much as possible since it produces nicely formed dimples and is relatively fast. In the case of formed skins, it takes an extra pair of hands to put one side away from the C-frame. As I found out a while back with the control surfaces, it helps to use a scrap piece of wood to hold the skin against the table. Well, in this case, the skin is thicker and wants to lift up a lot more. As I was moving along the front frame rivet line, the skin slipped off of the male dimple die, and when I struck the shaft, I knew right away that I had a big problem. Yep, I punched a new hole in the skin right next to the intended target. This is another one of my mistakes that I don't wish on anyone else.
I did all I could to flatten it back out using the flush set on my rivet gun and a bucking bar, and dimpled the correct hole. However, it was a lost cause because the skin cracked when I flattened the mistake - actually, it was a futile attempt anyway since the hole was so close and another crack immediately formed between the two holes. Almost funny given my day job.... Anyway, after thinking it over and having a discussion with a good buddy (Tom Dieter's), I'll be cutting out the damage and fabricating a repair patch with a filler inside the cut-out. Boy, this was a day I wish I could do-over.
Also, for what it may be worth, I've found that when this kind of thing happens it's better to stop and let things sit a while. Very hard to do, and I didn't exactly follow that advise as much as I should have - although flattening the skin made me feel like I was doing something at the time. The situation doesn't seem as bad today as it did yesterday. It's fixable, and I'm grateful that it was on the bottom surface. :-) Moving on.....
11 May 2013 (3.5 hours, total time to date: 665.5 hours)
No drama today - thankfully. De-burred, finished,& dimpled the skin attach holes on the left side of the stabilizer, left stab cap fastening strip, and remaining few holes in the left skin. I decided to use the old hand squeezer for most of the holes since I already had the appropriate yoke on it. It was easy to control the amount of pressure used and it doesn't take too much - once the male die is in the hole, it stays there. I had to use my vice grip dimpler for the forward holes on each side of the tip rib, and I countersunk the attachment holes on each side of the forward attachment fitting on the root rib. I also had to remove one bolt on the outboard elevator hinge fitting to dimple one of the holes on each side of the rear spar.
Used a scotch brite pad to remove dimple die marks, light scratches, and to prepare the mating surfaces for priming. De-greased the parts, and applied a self-etching primer to the internal mating surfaces.
Used a scotch brite pad to remove dimple die marks, light scratches, and to prepare the mating surfaces for priming. De-greased the parts, and applied a self-etching primer to the internal mating surfaces.
12 May 2013 (3.5 hours, total time to date: 669.0 hours)
Decided to stop drill the crack at the "oops" hole in the left stab skin - I used a #50 bit and a drilling template to position the hole over the crack tip. I replaced the left skin on the stab frame (temporarily), and removed the right side skin for finishing. I removed the protective plastic, and de-burred the right side skin holes & edges. Beth helped hold the skin while I dimpled most of the skin holes in the C-frame (there are a few remaining on the tip and root toward the leading edge). Also, de-burred and dimpled the right stabilizer cap fastening strip. Finally, I de-burred all of the holes on the upper, right side of the stabilizer frame.
13 May 2013 (3 hours, total time to date: 672.0 hours)
Turned the stabilizer frame over, de-burred, & finished (scotchbrite pad) the skin attachment holes on the lower right side of the stabilizer frame. Dimpled the remaining holes in the right stabilizer skin using my hand squeezer and dimpled the attachment holes in the right side stabilizer frame. As was done on the left side, the forward holes on the root rib (forward stabilizer attach fitting area) were C/S since the steel fitting can not be dimpled. Also, it was necessary to use my vice grip dimpler for the forward holes on the tip rib due to space limitations. I went over the frame again with a scotchbrite pad and fine steel wool to remove dimple die marks. Finally, I de-greased & primed the internal mating surfaces.
14 May 2013 (2 hours, total time to date: 674.0 hours)
Replaced the right stabilizer skin in preparation for final riveting.
Drilled additional attachment holes on each side of the damaged hole on the left bottom stabilizer skin (along the front spar). Per discussion with Tom Dieters, I placed the new holes approx. 1/3 the distance to the adjacent holes. Removed the skin, de-burred the holes, & dimpled the skin & spar. Finally, touched up the primer on the mating surfaces.
Drilled additional attachment holes on each side of the damaged hole on the left bottom stabilizer skin (along the front spar). Per discussion with Tom Dieters, I placed the new holes approx. 1/3 the distance to the adjacent holes. Removed the skin, de-burred the holes, & dimpled the skin & spar. Finally, touched up the primer on the mating surfaces.
15 May 2013 (1 hour, total time to date: 675.0 hours)
Replaced the left stabilizer skin and started work riveting the right skin to the stabilizer frame using my pneumatic squeezer.
16 May 2013 (1 hour, total time to date: 676.0 hours)
Continued riveting the bottom right skin to the stabilizer frame. I had to drill out 2 rivets and replace them. One shop head split, and one was bent too much for my liking. I still like the new squeezer, but you can't get around the operator error problem :-).
17 May 2013 (2 hours, total time to date: 678.0 hours)
Continued riveting the stabilizer skin. I worked on the left bottom main spar line and had more drill outs. I'm wondering if a shorter yoke would help in this case. I had a few split heads, a few that bent (although the rivet length was correct), and there seems to be a tendency for one side of the dimple to collapse. Maybe it's still operator error, but I'll try a shorter yoke and see if it is easier to control.
18 May 2013 (2.5 hours, total time to date: 680.5 hours)
Switched to a smaller yoke using a flush squeezer die on each side. This worked better for me, but I'll have to switch back to the no hole yoke for the forward rivets on the tips. Also, it seems to work better to set the rivets and go back and finish them. I took my time and finished the bottom left tip (excluding the forward rivet), right root line, and got about 1/2 way done with the left root line.
Also, for what it may be worth. Scotch tape on the flush rivet set really helps cut down on surface scratches and has no ill effect(s) on the process. You just need to change it from time to time - a little acetone makes short work of it. I leaned this from my RV builders class (Troy Grover).
Also, for what it may be worth. Scotch tape on the flush rivet set really helps cut down on surface scratches and has no ill effect(s) on the process. You just need to change it from time to time - a little acetone makes short work of it. I leaned this from my RV builders class (Troy Grover).
19 May 2013 (2.5 hours, total time to date: 683.0 hours)
Finished riveting the bottom left root & tip rib line. I had to switch back to the 4 in. no hole yoke to get to the forward rivet in the root line (I needed to use it for the forward rivet at the tip anyway. After initially setting the rivets with the squeezer, I sometimes used my rivet gun to set the heads flush with the skin. I had one bad installation to drill out. I also inspected all of the rivets and decided to replace four more that I thought I could improve. They all look pretty darn good now. I used a scotch brite pad to go over the skin and buff out some scratches, and polished the surface along the rivet lines. I turned the stabilizer over, and began riveting the upper surface. Finished the left upper tip line and started on the right root.
20 May 2013 (2.5 hours, total time to date: 685.5 hours)
Finished riveting the bottom right root rib line as well as the final tip rib rivet. Scratch what I wrote before about setting the rivet with the squeezer and then finishing it. I had a lot of trouble bending rivet heads along the root rib (had to replace 5). I tried to avoid bending by watching the position of the rivet dies wrt the shaft, but on the curved surfaces, this often results in the flush head not being flush on the surface (one side lifted). If I was careful to keep the die flush to the surface, the head would often bend. After re-doing a few, I tried holding the die flush on the skin and quickly driving the rivet nearly all of the way - just leaving a little room to get all the heads as uniform as possible. After finishing the solid rivets, I installed Cherry Max rivets along the bottom forward spar. Unfortunately one of the Cherry Max rivets did not clamp up fully. It is loose, and I'll have to deal with it tomorrow.
21 May 2013 (1.5 hours, total time to date: 687.0 hours)
Mixed up a small batch of T-88 structural epoxy to fill the holes next to the damaged hole on the front spar line and decided to use it to help hold the bad Cherry Max so I can drill it out. The T-88 is supposed to work as a filler, so I hope it will work well to fill the holes. While the epoxy was setting, I decided that it would be a very good idea to try drilling out a couple of Cherry Max rivets on a test piece of aluminum. Well, it was not that easy.... You need to drill down far enough to remove a retaining ring around the pulling stem. I tried it on two rivets, broke two new drill bits, and gouged the surface of the test piece. Thankfully, I didn't try it on the stabilizer. I'll have to make some calls to see if I can get some help with this. When the epoxy had set enough, I sanded & finished it to be flush with the skin surface. To wind down the work for the day, I finished the sharp end of the pulling stems on the bottom front spar line with my dremmel tool.
22 may 2013 (1 hour, total time to date: 688.0 hours)
I installed Cherry Max rivets along the top left & right stabilizer front spar rivet line. Two on the left side seem a little loose. I removed the clecos along the aft end of the top side to take a look and noticed that there is a slight gap between the skin and frame flange near these rivets. I called an A&P I know and asked him to come over and take a look.
23 May 2013 (1 hour, total time to date: 689.0 hours)
Started working on the rudder while waiting for Jasson and Tim to come over and take a look at the stabilizer. I removed the rudder stiffeners, and used a scotch brite pad along the inside of the skin to prepare for bonding the stiffeners with T-88 epoxy. De-greased the inside of the skin and stiffeners. Mixed s small batch of T-88, applied a thin layer to one of the lower stiffeners, & riveted it in place. It was a little tricky to get the bucking bar to the last rivet (next to the bend in the skin). My smallest tungsten bar just fit with a little effort. I had to drill out one rivet, but the epoxy has a long pot life, so I had plenty of time.
Jasson & Tim (A&P's - Jasson is also an IA) came over to look at the stabilizer and decided to take it back to their shop to remove the bad Cherry Max rivets. I'm hoping to be able to pick it up sometime tomorrow. They also looked over the airplane and told me that everything looks great! They gave me several good ideas, and I plan to have them back to help with other parts of the process in the future.
Jasson & Tim (A&P's - Jasson is also an IA) came over to look at the stabilizer and decided to take it back to their shop to remove the bad Cherry Max rivets. I'm hoping to be able to pick it up sometime tomorrow. They also looked over the airplane and told me that everything looks great! They gave me several good ideas, and I plan to have them back to help with other parts of the process in the future.
24 May 2013 (1.5 hours, total time to date: 690.5 hours)
Continued work bonding/riveting the rudder stiffeners to the skin. Because of the angle, it is awkward to rivet the stiffeners in the arrangement shown the the previous photo. I decided to lay the rudder between 2 scrap pieces of 4x4 covered with a towel. The height of the 4x4s allow room for the clecos, and the angle of the skin is a much more comfortable position for handling the rivet gun (also the rivets won't keep falling out - ;-) ). Another thing that seemed to be a big help was to use a piece of scotch tape to over the rivet head (instead of the flush rivet set). I folded over a small tab (to make it easy to take the tape off when done), and taped over the head (I found that you can use the tape a couple of times before replacing it). This serves a few very good purposes: 1) It helps to keep the head flush 2) It protects the skin, 3) It provides a very good reference for centering the rivet gun, & 4) Let's you know which rivet you're supposed to be driving. The last point may seem a little funny, but since I try to install the rivets in an alternating pattern, it gets more helpful as you fill up the row.
25 May 2013 (2 hours, total time to date: 692.5 hours)
Continued bonding/riveting the stiffeners to the rudder skin. Finished the left side and am making my way along the right. Now that the left side is riveted, I moved the towel and rudder over to my work table since it will now lay flat on the left side.
26 May 2013 (1.5 hours, total time to date: 694.0 hours)
Continued bonding/riveting stiffeners to the rudder skin. My shoulder gets a little sore, so I am doing the work in smaller doses. Being as careful as possible not to damage the thin skin.
27 May 2013 (1.5 hours, total time to date: 695.5 hours)
Finally finished bonding/riveting the stiffeners to the rudder skin. Inspected all of the 80 rivets and found a few that I'd like to replace. I'll wait until the epoxy is well set. The bond lines look very good, and I'm sure the epoxy would probably do the job by itself, but I'd like the rivets to be right.
28 May 2013 (1.5 hours, total time to date: 697.0 hours)
Drilled out & replaced 3 rivets in the rudder skin. Ran a new 3/16 bit through the rudder mounting brackets on the fin rear spar & replaced the rudder spar on the fin. Aligned the rudder spar & measured the distance along each side of the fin skin/rudder spar interface. Marked the fin skin for final trimming - I marked the skin to 14/32 from the rudder spar flange. The rudder skin is bent at approx. 30 degrees to sit inside the aft fin skin and allow clearance for rudder deflection. The bent rudder skin projects approx. 0.5 in. forward of the rudder spar flange at the top and slightly more toward the bottom. I need clearance for the rudder skin as well as enough space to install the hinge bolts, but want to have some overlap between the skins to help reduce drag. I'll cut short of the line to leave room for finishing and any slight adjustments required after rigging the rudder.
I used some acetone and scotch brite pads to clean epoxy residue, fingerprints, & light scratches from the outside of the rudder skin. Finally, I wiped down the skin (inside & out) with my PPG de-greaser. I'll need to polish it more after fitting it to the airplane.
I used some acetone and scotch brite pads to clean epoxy residue, fingerprints, & light scratches from the outside of the rudder skin. Finally, I wiped down the skin (inside & out) with my PPG de-greaser. I'll need to polish it more after fitting it to the airplane.
29 May 2013 (1.5 hours, total time to date: 698.5 hours)
Marked and used my angle die grinder to taper the sides of the angle reinforcement on the rudder spar as indicated in the drawings. Finished the edges of the angle using fine sandpaper and scotch brite.
Laid out the lower rudder rib & rudder skin to measure the location of the bend in the rudder tab. I used a 4 ft piece of 1x4 with a towel to protect the rudder skin and started working to tighten and close the rudder skin. I didn't make much progress tightening the bend, but want to be careful not to damage the skin. Finally, I fabricated 1x4 oak forming blocks and a pine spacer to be used to bend the tab in the lower rudder rib.
Laid out the lower rudder rib & rudder skin to measure the location of the bend in the rudder tab. I used a 4 ft piece of 1x4 with a towel to protect the rudder skin and started working to tighten and close the rudder skin. I didn't make much progress tightening the bend, but want to be careful not to damage the skin. Finally, I fabricated 1x4 oak forming blocks and a pine spacer to be used to bend the tab in the lower rudder rib.
30 May 2013 (1 hour, total time to date: 699.5 hours)
Bent the flange in the lower rudder rib using the forming blocks and a rubber mallet. Finished the bend in my nifty flanging tool (photo - Jan 2, 2013). Laid out locations for fasteners along the reinforcing angle. Tried to think ahead a bit here because I need to be able to buck the rivets (or at least pull blind fasteners if it comes to that). There must be enough clearance between the spar and the rivet gun/puller to be able to get a flat set on the rivet heads. That means a little more than 0.65 inches from the spar web as a minimum. A similar problem exists for the bent flange on the rib. I can't find any reference about attachment of this flange to the steel portion of the rudder rib, but if it is to be attached there is very little "wiggle" room because of the rudder stops that are welded on the spar. I'll see if I can get some more information from Chris at Mustang Aeronautics, but it doesn't seem necessary to attach the rib flange since I can get 5, 1/8 in. rivets in the reinforcing angle, and the skin will also be riveted to the spar flange.
31 May 2013 (1 hour, total time to date: 700.5 hours)
Finalized the fastener hole locations on the rudder lower rib flange/reinforcing angle interface. Drilled #40 pilot holes in the rib on the drill press, positioned/aligned the rib on the spar, & match drilled the holes in the reinforcing angle. While aligning the rib, I saw the need to "tweak" the bend in the rib tab - used the flanging tool again. The fit turned out very well.
I couldn't reach Chris, so I did a little more checking on how I could attach the rib tab to the spar. It looks like I can get 2 rivets on each side of the tab, but will have to position the holes accurately in the lower steel portion of the spar. There are "pockets" of space on each side of the rudder stops & lower hinge that will allow a little over 0.5 in. dia. (required for my universal rivet set). Also, I quickly laid out the rivet location for the rudder spar tip rib attachment.
I couldn't reach Chris, so I did a little more checking on how I could attach the rib tab to the spar. It looks like I can get 2 rivets on each side of the tab, but will have to position the holes accurately in the lower steel portion of the spar. There are "pockets" of space on each side of the rudder stops & lower hinge that will allow a little over 0.5 in. dia. (required for my universal rivet set). Also, I quickly laid out the rivet location for the rudder spar tip rib attachment.
1 Jun 2013 (2.5 hours, total time to date: 703.0 hours)
Drilled the tip rudder rib #40 pilot attachment hole in the spar using a scrap piece of aluminum as a drilling guide. Aligned the tip rib on the spar & match drilled the #40 hole in the rib flange.
I fabricated a 0.55 dia. disk from some o.o63 scrap to use as a drilling guide for the rudder root rib flange attachment. This will allow me to position the holes in the lower steel portion of the rudder spar so that I'll be able to get the rivet set between the lower hinge & rudder stops. This area is very confined. I drilled a #41 hole in the scrap & rough cut the disk in the band saw. I then used the drill bit shank as an axle, and finished the disk on the sander and scotch brite wheel. It took several iterations to get the disk finished and I managed to burn my fingers a bit. In the end, it was well worth the effort to get the holes properly positioned.
Finally, I laid out the tail wheel steering arms on the lower portion of the spar as indicated in the drawings. The part comes with #31 pilot holes, so I clamped the arms in place & match drilled the pilot holes through the spar. Then I drilled out the holes in 2 steps up to #21 (in turn), and clecoed them in place.
I fabricated a 0.55 dia. disk from some o.o63 scrap to use as a drilling guide for the rudder root rib flange attachment. This will allow me to position the holes in the lower steel portion of the rudder spar so that I'll be able to get the rivet set between the lower hinge & rudder stops. This area is very confined. I drilled a #41 hole in the scrap & rough cut the disk in the band saw. I then used the drill bit shank as an axle, and finished the disk on the sander and scotch brite wheel. It took several iterations to get the disk finished and I managed to burn my fingers a bit. In the end, it was well worth the effort to get the holes properly positioned.
Finally, I laid out the tail wheel steering arms on the lower portion of the spar as indicated in the drawings. The part comes with #31 pilot holes, so I clamped the arms in place & match drilled the pilot holes through the spar. Then I drilled out the holes in 2 steps up to #21 (in turn), and clecoed them in place.
2 Jun 2013 (4 hours, total time to date: 707.0 hours)
Taped the skin in position & test fit the lower fiberglass bottom to check the overall fit. It looks very good - the fiberglass piece butts up against the skin right at the midpoint of the lower rib flange! Gotta give credit to MA. I then went to work to tighten up the trailing edge bend in the skin to get it to lay flat on the ribs and relieve the stress at the aft edge of the stiffeners. I cut 2, 4 ft lengths of 1x3s & clamped them across the bend. Increased the pressure in increments to check progress and got fairly close to what I wanted. I may have been able to do it all with the boards, but decided to finish carefully with my vice-grip seaming pliers. I used painters tape in the inside of the seaming pliers to reduce the tendency to mark the surface & moved along the edge with several passes gently increasing the grip. I finally got the skin to lay flat - looks pretty good (nice straight line all of the way to the tip). I can see minor tool marks, but not bad at all. I think the paint will cover them. Then, I measured & marked the location of the skin cut-outs for the hinge bolts. I drilled out the corners to 3/16, but centered the holes 1/4 in. from the final dimensions since I use a 1/4 in. dremel sanding drum to finish. Make the rough cuts with my cut-off wheel & used a sanding disk to get to the edges. Finished with fine sand paper and scotch brite pads.
Replaced the skin on the frame. Measured, measured, and measured the rivet line along the spar flange. The 30 degree skin bend is positioned at the edge of the flange and it makes a good reference on the surface. The flange is fairly wide (~0.7+), so I went in about 0.35 from the bend line. I marked the intersection with the existing rivet lines for the stiffeners and marked rivet spacings to be uniform between each of these holes. Made a small drilling template and started drilling out the #41 pilot holes along the spar (just taped the template in position for each hole). I took my time here, and I'm sure it will pay off on the other side. Its starting to look like a rudder!
Replaced the skin on the frame. Measured, measured, and measured the rivet line along the spar flange. The 30 degree skin bend is positioned at the edge of the flange and it makes a good reference on the surface. The flange is fairly wide (~0.7+), so I went in about 0.35 from the bend line. I marked the intersection with the existing rivet lines for the stiffeners and marked rivet spacings to be uniform between each of these holes. Made a small drilling template and started drilling out the #41 pilot holes along the spar (just taped the template in position for each hole). I took my time here, and I'm sure it will pay off on the other side. Its starting to look like a rudder!
3 Jun 2013 (1 hour, total time to date: 708.0 hours)
Measured, marked, and drilled the #41 pilot holes along the other side of the rudder spar flange at the intersections of the stiffener rivet lines.
I picked up the stabilizer from Jasson. He ground out the retaining rings on a total of 8 Cherry Max rivets that he thought should be replaced. He also loaned me his pneumatic puller. I'll be switching back to the stabilizer to get it closed up.
I picked up the stabilizer from Jasson. He ground out the retaining rings on a total of 8 Cherry Max rivets that he thought should be replaced. He also loaned me his pneumatic puller. I'll be switching back to the stabilizer to get it closed up.
4 Jun 2013 (1 hour, total time to date: 709.0 hours)
Drilled out the poorly installed (who did that, anyway???) Cherry Max rivets using a #31 bit (per Jasson). It worked very well - I could not see any hole damage. I had to use small vice grips on the inside to keep a few of them from rotating, but most of them came out easily. The one that I had epoxied was a little more trouble since the head wanted to stay, but a little gentle work with my de-burring bit got it out cleanly. Then, I just had to use some elbow grease with a scotch brite pad and some acetone to get the epoxy off the skin around the hole. Finally, did a little general polishing and wiped the skin down with a little acetone to remove my fingerprints and the oil from my air drill.
I took the picture below before removing the last Cherry Max. Once the ring is gone & the stem is driven out, there's not much to them.
I took the picture below before removing the last Cherry Max. Once the ring is gone & the stem is driven out, there's not much to them.
5 Jun 2013 (1 hour, total time to date: 710.0 hours)
Jasson loaned me his pneumatic rivet puller, and since I've never used one, I fabricated a test coupon to check the operation. I set the pressure to 60 psi, and applied moderate pressure to hold the head firmly to the skin and it worked very well. The first try on the stabilizer ended up with a minor scratch (buffed it out) when the head bounced. After that I used painters tape around the hole, but got more used to holding the gun in place. I think the tape is a good idea anyway. I finished all of the remaining Cherry Max rivets along the front frame of the stabilizer.
6 Jun 2013 (1 hour, total time to date: 711.0 hours)
Well, I thought I was done with the Cherry Max rivets, but I found a few more loose ones. I think I'll be using them a lot less than I was thinking. I was using my Dremel tool to clean up the stems on the rivets and carefully inspecting them (inside & out) when I noticed 2 more very loose rivets near the root rib on the bottom right side. Also, from the inside I can see two other areas that don't look as tight along the seam. I'll head over to Warren Co. Airport at lunch time tomorrow - Jasson told me that he can grind out the collars on any more bad ones. All I can say is better now than when I have the stabilizer completely closed. I hope that they don't work loose over time. It's definitely hard to reach inside (especially near the tips) to buck solid rivets, but now I'm a little disappointed with my experience with Cherry Max rivets so far.
7 Jun 2013 (1.5 hours, total time to date: 712.5 hours)
Jasson ground out the collars and tapped out the stems of 4 more Cherry Max rivets for me, and I drilled out the rivets. It looks like the dimples aren't lined up perfectly, but I can't see how to avoid it. Solid rivets would pull the skins together better, but as I've already written, it's darn hard to reach all of the way along the front frame. Anyway, I fabricated a washer from some scrap 0.062 sheet and tried using a wing nut cleco to pull the skin tighter. Of the 4 replacement Cherry Max rivets, 3 seem to be OK (at least for now). One is loose, but is relatively close to the root. I'm hoping I can ask Jasson to grind this one out, and I can try using a solid rivet.
I'm going to be out of town for a few days. It's probably a good thing because I think I need a break.
I'm going to be out of town for a few days. It's probably a good thing because I think I need a break.
15 Jun 2013
I flew my Cherokee up to Troy, MI to attend the Mustang Aero Open House. I'm very glad I went to see the place and talk to Chris and Ross. My forward fuselage kit was on display and is just about ready to be shipped. I also was lucky enough to get a ride in Ross's beautiful Mustang II. I can't thank him enough for letting me get a feel for the performance of that airplane. I'm really looking forward to getting mine finished one of these days ......
17 Jun 2013 (1 hour, total time to date: 713.5 hours)
OK, back to work...
I've been spending some time putting a 4x3 top on a base cabinet that I had in the garage to give me more horizontal work space. It's nearly ready to go, and I decided to spend some time building a stand to hold the stabilizer for storage and to help me buck solid rivets along the front frame. I measured and cut slots for the leading edge in 2 pieces of 1/2 think plywood & attached 14 inch long 2x4 boards to each to serve as a base. I also cut some scrap 1/4 inch plywood into 3 foot lengths to use along the sides.
I've been spending some time putting a 4x3 top on a base cabinet that I had in the garage to give me more horizontal work space. It's nearly ready to go, and I decided to spend some time building a stand to hold the stabilizer for storage and to help me buck solid rivets along the front frame. I measured and cut slots for the leading edge in 2 pieces of 1/2 think plywood & attached 14 inch long 2x4 boards to each to serve as a base. I also cut some scrap 1/4 inch plywood into 3 foot lengths to use along the sides.
18 Jun 2013 (1 hour, total time to date: 714.5 hours)
Finished the stabilizer stand. Now, as soon as I can get a couple of coats of polyurethane on my large table, I'll get back to work on the fin/rudder.
19 Jun 2013 (1.5 hours, total time to date: 716.0 hours)
Double checked & marked the rivet line along the rudder spar flange. Laid out the location of the intermediate rivets (between the stiffeners) along the spar & along the bottom rib on the left side. Drilled the #40 pilot holes using a single hole drilling template. The template was good for about 4-5 holes before I needed to replace it.
20 Jun 2013 (1 hour, total time to date: 717.0 hours)
Drilled the pilot holes on the right side of the rudder along the lower rib and spar flange. Once I get the fin skin trimmed and cut slots on the left side of the rudder skin for clearance with the hinge fittings, I'll be able to test fit the rudder.
21 Jun 2013 (2 hours, total time to date: 719.0 hours)
I used my angle die grinder with a sanding disk to carefully trim the trailing edge skin on the fin. I left it a little long until I could see how the rudder would fit. I think I may need to sand it a little bit more, but will wait until I check the final fit and required range of motion. I measured, removed the rudder skin from the frame, and cut notches in the left rudder skin flange to accommodate the upper hing fitting. Since I don't see a need to access both sides, I decided to keep the left side closed as much as possible. However, the notch radii are small, so I will probably cut out the center to allow me to use larger corner radii (1/8+ in.) and still keep the opening relatively small. I also cut out a notch on the left lower hinge area. I finished the edges of the cuts and made a few trial fits on the fin. It took 2 iterations to get the cuts adjusted to fit and allow room to get the bolts installed.
22 Jun 2013 (2 hours, total time to date: 721.0 hours)
Marked areas to trim on the rudder skin (tab area on the left side at the upper hinge & the bottom hinge area on each side). Removed the rudder/skin & trimmed/finished the marked areas. Also, cut/finished the upper skin trailing edge for the fiberglass tip. Made a trial fit of the tip & found that the leading edge needed to be trimmed as well. Made a few iterations until I was happy with the fit & finished the areas. Sanded/finished the trailing edge fin skin again based on the clearance issues I found when I initially fit the rudder.
I replaced the rudder to re-check the fit. It looks pretty good. If anything, I may need to trim a little more off of the fin skin on the bottom right, but will wait until I am closer to finishing the rudder.
I replaced the rudder to re-check the fit. It looks pretty good. If anything, I may need to trim a little more off of the fin skin on the bottom right, but will wait until I am closer to finishing the rudder.
23 Jun 2013 (2 hours, total time to date: 723.0 hours)
I noted the position of the rudder fiberglass tip, removed the rudder, replaced the fin tip, & marked the trailing edge initial trimming line to allow clearance for the rudder tip. Then, I aligned the rudder tip rib along the extended fin tip skin line (leaving the 0.5+ edge for attachment of the fiberglass tip). Clamped the tip rib in place & laid out the position of rivets along the rib. Here's where it gets more interesting. The tip is very thin, so it is not possible to buck rivets (not to mention dimpling) very far from the rudder spar. I decided to use one -4 rivet at the forward position (~0.5 in. from the forward edge), and one -3 rivet 1 inch aft (on the other side, 1.25 inches aft for clearance with the squeezer yoke. I took a little extra time to measure & measure again. That's about all I believe I can do with mechanical fasteners along the tip rib. I'll use some T-88 epoxy along the rest of the rib when I finally close it up. I drilled the #40 pilot holes (#41 for the 2, aft holes). I de-greased and applied a light primer to the rib flange. Based on my experience riveting the tip rib on the fin spar, I thought I'd wait until this point to rivet the tip rib on the rudder. It seemed like it would help to have the rib secured in place with clecos and use my squeezer to rivet it to the spar. Clecos in the forward holes were in the way, so I taped flush head -3 rivets on the inside to help hold the rib in line. This worked, but was more time consuming. Finally, I made the initial trimming cut on the trailing edge of the fiberglass fin tip.
24 Jun 2013 (1 hour, total time to date: 724.0 hours)
Removed the rudder skin from the frame & drilled the attachment holes in the spar reinforcement angle/bottom rib to #30. I decided to leave the holes in the bent flange #40 because of the close (~0.2+) edge distance on one side. They are there to hold the flange against the spar and don't carry much (if any) real load because of the main attachment at the rib web/reinforcement angle. I de-burred the holes, finished, de-greased the mating surface areas on the rib, & applied a thin coat of primer. I will rivet the lower rib to the spar before drilling out the skin attachment holes to #30. I ordered a longeron squeezer yoke & will need to use it to squeeze the rivets in the reinforcement angle (since the lower rib flange is too wide for the standard yokes). It will be needed for my longerons later (imagine that....).
25 Jun 2013 (1 hour, total time to date: 725.0 hours)
Replaced the rudder skin & mounted the rudder on the fin to make the final measurement for the fin tip. I marked, cut, & finished the trailing edge cut on the fin tip. I don't think I noted this before, but there is a slight alignment issue with the rudder. I noticed it a lot more with the tips installed. I called MA and talked with Chris about it since the alignment is set by the location of the hinge fittings which were done by MA. Chris has been very helpful and told me that he is happy to give me some new upper fittings that I can re-drill to correct the issue.
After looking at it in much more detail, it looks like the upper hinge bearing fitting is slightly offset (at least by "eye-balling" it). I will try inverting the fin fittings to see if that has any effect before deciding what to do about it. Just for the record, the scratch in the spar (below) was already there when I got the part. Not that I am immune from making scratches, but I have to admit that it's nice to be able to say I didn't do this one. :-)
After looking at it in much more detail, it looks like the upper hinge bearing fitting is slightly offset (at least by "eye-balling" it). I will try inverting the fin fittings to see if that has any effect before deciding what to do about it. Just for the record, the scratch in the spar (below) was already there when I got the part. Not that I am immune from making scratches, but I have to admit that it's nice to be able to say I didn't do this one. :-)
26 Jun 2013
Well, I didn't make any progress on the airplane, but was able to determine for certain that the rudder spar bearing fitting was offset approx. 0.07 - 0.075 inches. This explains the approx. 0.1 offset at the tip. It looks like I'll need to take Chris up on the offer for the upper hinge bracket blanks and I'll have to match drill the attachment holes with the appropriate offset. I'm not really upset with MA - I could have easily done the same or worse. They really do a good job with the kit, and have saved me a lot of time.
27 Jun 2013 (0.5 hour, total time to date: 725.5 hours)
I haven't had as much time as usual to work on the Midget this week since Jasson has been doing the annual on my Cherokee in the evenings. However, I was able to spend a little time on the Midget today. While waiting for the new rudder upper hinge fittings, I'm turning my attention to the elevator. I mounted the elevator spar on the stabilizer spar to check to be sure it was aligned - it is. Also, the elevator stiffener flange on the bottom of the left skin (at the trim tab cut-out) extends slightly past the cut line. I bent it inward slightly to provide clearance for the trim tab.
28 Jun 2013 (1 hour, total time to date: 726.5 hours)
I tweaked the bend in the elevator stiffener flange to provide a little more clearance for the trim tab near the hinge. Then I put the left elevator skin away for the time being. I decided to rivet the stiffeners on the right skin first to give me a little more time to consider any other issues that may arise in the left skin due to the trim tab cut-out. I scuffed up the mating surfaces of the stiffeners and skin using a heavy duty scotch brite pad. I used a cross hatch pattern on the stiffeners and a circular motion on the skin. I de-greased the parts with my PPG 330 de-greaser, wiped them down with a clean cloth, & clecoed them back together in preparation for bonding/riveting.
29 Jun 2013 (2.5 hours, total time to date; 729.0 hours)
Bonded/riveted the stiffeners on the bottom of the right elevator skin. The T88 epoxy is easy to mix and clean up (as you go). Using scotch tape over the rivet heads works extremely well, and after a lot of trial and error, I've found that my small (~2.5x0.75x0.75) tungsten bucking bar works best when used on along the long side. I use the stiffener sides as a guide and have the gun at a little under 30 psi.
30 Jun 2013 (5 hours, total time to date: 734.0 hours)
Finished bonding/riveting the stiffeners on the top right elevator skin. Prepared (scuffed & de-greased the mating surfaces) the stiffener/skin for the left elevator & bonded/riveted the stiffeners on the top of the left elevator. Spent a little time checking the fit/function of the trim tab. I'll have to do some thinking about how I'm going to attach the trim tab control arm.
1 Jul 2013 (2 hours, total time to date: 736.0 hours)
Finished bonding/riveting the stiffeners to the elevator skins!
3 Jul 2013 (1 hour, total time to date: 737.0 hours)
Carefully folded the elevator skins to tighten the trailing edges. I covered the skin with a towel and clamped a piece of 1x4 across the edge. This is not enough to finish the bend, but it gets it a little closer. The only way I've found to get the final shape (flat skin on the spar) is to finish up with vice-grip seaming tool. I used blue painters tape on surfaces of the tool to help protect the skin, and very carefully worked along the edges - gradually tightening the grip. The bend is tighter as you move outboard, but in the end, you want the leading edge opening to be just slightly less than the spar thickness. If it's too large, there will be a bulge in the trailing edge, too little, and there will be a dip. No surprise, right, but you really want a nice flat surface. Once finished, I started laying out the spar and ribs. For some reason, I was thinking the forked end of the elevator control was supposed to be on the top, but after double checking, it is definitely on the bottom. The control rod from the stick goes under the seat and attaches to the lower end of the elevator bell crank. The rod from the upper end of the crank goes to the elevator control horn. Therefore, when the stick is pulled back, the rod to the control horn will move aft. This will result in an upward elevator movement only if the rod is attached on the lower end of the control horn. Just had to be sure to get this straight before moving on.....:-)
4 Jul 2013 (3 hours, total time to date: 740.0 hours)
Happy 4th of July!
It seems a little silly/embarrassing that it actually took me 3 hours to align and drill the attachment holes for the two root ribs on the elevator spar. As I started, I noted that the left and right spar webs weren't parallel. No big deal, since the main thing would be to make sure both ribs were aligned to each other. I started with the right rib, being careful to watch the edge distance of the holes next to the web. The rib flanges are slightly thinner than the spar flange when projected to the spar, so as the drawing indicates, the rib rivets should not be too close to the spar. The steel attachment tabs have pilot holes, but not enough space between to use a standard drill. I started using an angle attachment on my dremel tool, but it didn't work well with the steel. I switched to a 12 inch bit that I could flex enough to get the job done. The bulk of the time was spent checking, checking, checking ..... the alignment of the left rib to the right one. I used a level and a plumb bob, but in the end, eyeballing along the spar (using the outer hinge fittings, the C/L of the ribs and spar) worked best. I checked to be sure each side was parallel (when I thought I had things lined up) by laying the spar on it's side and checking the each rib touched a flat board. Anyway, there was a lot of checking and double checking.
It seems a little silly/embarrassing that it actually took me 3 hours to align and drill the attachment holes for the two root ribs on the elevator spar. As I started, I noted that the left and right spar webs weren't parallel. No big deal, since the main thing would be to make sure both ribs were aligned to each other. I started with the right rib, being careful to watch the edge distance of the holes next to the web. The rib flanges are slightly thinner than the spar flange when projected to the spar, so as the drawing indicates, the rib rivets should not be too close to the spar. The steel attachment tabs have pilot holes, but not enough space between to use a standard drill. I started using an angle attachment on my dremel tool, but it didn't work well with the steel. I switched to a 12 inch bit that I could flex enough to get the job done. The bulk of the time was spent checking, checking, checking ..... the alignment of the left rib to the right one. I used a level and a plumb bob, but in the end, eyeballing along the spar (using the outer hinge fittings, the C/L of the ribs and spar) worked best. I checked to be sure each side was parallel (when I thought I had things lined up) by laying the spar on it's side and checking the each rib touched a flat board. Anyway, there was a lot of checking and double checking.
5 Jul 2013 (3 hours, total time to date: 743.0 hours)
De-burred & finished the holes & edges on the elevator root ribs. Cleaned the parts with acetone, used scotchbrite on the rib webs, de-greased, & applied a light coat of primer on the mating surfaces. While the primer was drying, I decided to try out my new longeron yoke to rivet the lower rib on the rudder spar. I removed the rudder skin, and found that the new yoke did not quite fit over the wide flange. I decided to use my 3 inch yoke to rivet the -3 rivets holding the lower rib flange to the lower steel portion of the spar. It was a tight fit (as I knew it would be), and I will need to go back and replace one of the rivets later (a faint little smiley on the head). Otherwise, it worked out well. Then, I realized that I could use a my higher profile flat die with a couple of #10 washers to give me just enough clearance to reach the -4 rivets in the rib web/reinforcing angle. This also worked quite nicely with one exception - I bent one rivet. I drilled that one out, and did it again correctly. I then replaced the rudder skin and put the rudder away for the time being. I really like the way you can get a very nice shop head with the squeezer, and the ability to set universal heads by myself is also a big plus. I just haven't been able to keep the gun from bouncing off the protruding head with one hand, so this is the way to go if you don't have a helper to set universal head rivets. Finally, I finished off the day getting ready to rivet the root ribs to the elevator spar. I replaced the ribs, and checked the rivet length. The holes were too tight (Primer???), so I ran my 12 inch #30 bit through all of the holes again. I removed the ribs, did a little more light de-burring, & touched up the primer.
6 Jul 2013 (4 hours, total time to date: 747.0 hours)
As I started work riveting the root ribs on the elevator spar, it became clear that I wasn't going to be able to reach the 2 rivets closest to the spar on each side using my squeezer (or gun for that matter). The angle of the steel attachment tab and proximity to the spar makes it impossible.
So, after some thinking, I realized that the best way for me to proceed was to remove the 3 #10 bolts attaching the two halves of the spar and see if I could find another way to buck those rivets. I tried using the old hand squeezer, but it was very difficult to get the die lined up squarely. I ended up bending a shop head in the process. Finally, I came up with the idea to use a 4x4 as base and buck the rivets with the universal set for my gun and a hammer. I cut the end of a 4 ft long 4x4 at the angle matching the angle of the tab (allowed me to lay the rib level on the angled bucking bar). The 4x4 would lay across the table so I could clamp it on the other side. I needed to set the rivets with the hand squeezer, and then finish them using the gun set and a hammer (I couldn't use the gun because it would not clear the frame as shown in the picture). It was a bit of a slow go, but patience won out...
After I finished the two ribs, I re-assembled the spar using new hardware (I don't like to reuse those fiber nuts too many times, and I don't think I'll need to take the spar apart again). I was fairly pleased with the results.
Then, I decided to go back to the rudder and fix the bad -3 rivet in the lower rib tab. Got the new one in just fine, and decided to squeeze the adjacent one just a little more. Well, as is ofter the case, better was the enemy of good enough. It is a little tricky to work around the rudder stop fittings, and I put a smiley in that rivet :-(. So, I had to remove and re-install that one as well. However, in the end, everything looked great!
To end the day, I put the elevator spar back on the stabilizer spar and measured the amount of stabilizer skin that will need to be trimmed (for enough clearance to install the nuts on the hinge bolts). Then, I placed the elevator skins in place for alignment. A good days work.
So, after some thinking, I realized that the best way for me to proceed was to remove the 3 #10 bolts attaching the two halves of the spar and see if I could find another way to buck those rivets. I tried using the old hand squeezer, but it was very difficult to get the die lined up squarely. I ended up bending a shop head in the process. Finally, I came up with the idea to use a 4x4 as base and buck the rivets with the universal set for my gun and a hammer. I cut the end of a 4 ft long 4x4 at the angle matching the angle of the tab (allowed me to lay the rib level on the angled bucking bar). The 4x4 would lay across the table so I could clamp it on the other side. I needed to set the rivets with the hand squeezer, and then finish them using the gun set and a hammer (I couldn't use the gun because it would not clear the frame as shown in the picture). It was a bit of a slow go, but patience won out...
After I finished the two ribs, I re-assembled the spar using new hardware (I don't like to reuse those fiber nuts too many times, and I don't think I'll need to take the spar apart again). I was fairly pleased with the results.
Then, I decided to go back to the rudder and fix the bad -3 rivet in the lower rib tab. Got the new one in just fine, and decided to squeeze the adjacent one just a little more. Well, as is ofter the case, better was the enemy of good enough. It is a little tricky to work around the rudder stop fittings, and I put a smiley in that rivet :-(. So, I had to remove and re-install that one as well. However, in the end, everything looked great!
To end the day, I put the elevator spar back on the stabilizer spar and measured the amount of stabilizer skin that will need to be trimmed (for enough clearance to install the nuts on the hinge bolts). Then, I placed the elevator skins in place for alignment. A good days work.
7 Jul 2013 (4 hours, total time to date: 751.0 hours)
I fabricated 4 more wood clamps to fit around the trailing edge of the elevator. I used 1/4 thick pine molding and cut 2 inch long pieces to use as a spacer (the clamps were still attached since the glue was still setting up when the pic was taken). I also used 3/4 in. wide foam weather stripping to protect the skin. I will probably be able to use them for the ailerons later. As long as the table is flat, getting an equal distance from the table to the center of the spar, leading, and trailing edges will align the elevator. However, I decided to level my table to make it easier to double check the alignment with my laser level. Once it was leveled, I did a check with the laser. Then, I laid out the rivet locations (2 in. spacing) along the upper right elevator spar. I did a lot of checking - I always get a little nervous about drilling that first hole. I measured the rivet line from the bend in the elevator skin and made sure that the spar edge was resting along the bend line. I ended up with 1.5+ inches from the elevator control arm to the skin to match the edge of the rib at the trailing edge of the elevator (it was a bit of a compromise between matching the rib flange and the outboard stab skin line). It turned out to be just shy of the outboard skin line of the stabilizer (~1/32). I located the inboard edge of the elevator spar flange and marked the first rivet hole 3/8 from that edge. To be sure that I was hitting the right spot on the spar (a rivet shop head in the steel fitting is very close to this location), I measured the distance from that hole location to the edge of the stabilizer skin. Then, I slid the elevator skin back and double checked that location on the spar. It all looked good, so I put the skin back, got it all in alignment again, and was ready to start drilling the #40 pilot holes. I made another 2-hole "memory stick" as a drilling guide with the 2 in. spacing and worked my way along the drilling line - checking by looking through the right tip, and making any slight adjustments. I located the final hole 9/32 from the edge of the skin.
8 Jul 2013 (2.5 hours, total time to date: 753.5 hours)
Laid out & drilled the #40 pilot holes along the upper right inboard rib line. I placed the last rivet hole approx. 3.5 in. from the trailing edge (furthest aft that will allow clearance for squeezing). The drawing indicates a spacing of approx. 3 in., but to make thing work out evenly, I used 2.5 for all but the last rivet. Then, I marked, checked, and drilled the rivet line along the top left spar flange.
9 Jul 2013 (3 hours, total time to date: 756.5 hours)
Laid out & drilled the pilot attach holes along the upper left inboard rib flange. Turned the stab/elevator over and re-leveled it. laid out the rivet lines on the bottom left & right elevator spar flange. Made a new 2-hole drilling guide, and drilled out the #40 pilot holes on the bottom left spar flange.
10 Jul 2013 (1.5 hours, total time to date: 758.0 hours)
Laid out & drilled the #40 pilot holes along the bottom left inboard rib flange. Checked the alignment again, and drilled the pilot holes along the bottom right spar flange. Laid out & drilled the pilot holes along the bottom right inboard rib flange. Now, the elevator skin is clecoed to the frame.
11 Jul 2013 (1 hour, total time to date: 759.0 hours)
Cut four strips of scrap 0.025 sheet to use as attach strips for the elevator tips. Checked the initial fit-up and rough trimmed the left stabilizer tip to make room for the elevator tip. Started drilling the attachment holes for the bottom left attach strip.
12 Jul 2013 (1.5 hours, total time to date: 760.5 hours)
Spent a little extra time measuring & checking to see how far along the elevator tip a -3 rivet can be squeezed with my no hole yoke. The elevator tip rib provides torsional rigidity, so I definitely need to be sure it's securely attached. I also need the tip attach strips, so I have to be a little creative here (no instructions provided). The furthest distance along the tip is approx. 2.4 inches from the spar rivet line. Therefore, I marked and drilled another pilot hole through the stack (skin, attach tab, & tip rib flange). The only way I can see to secure the attach strip near the aft end is to drill through the skin/attach strip as far down as possible so that I can open the skin slightly to squeeze those rivets (first, with some epoxy before riveting the tip rib in place). This means, I'll also have to cut the tip rib a little shorter, but will cut as little off as possible. Before I drill those holes, I'll wait until I remove the skin and check to see how far I can safely open the skin. Too bad, I didn't know this before I folded the skin, but I needed to check the fit anyway, so ......
I trimmed & finished the edges of the attach strips for the right side. Then, I drilled the same #4o attachment holes in the lower right side.
I trimmed & finished the edges of the attach strips for the right side. Then, I drilled the same #4o attachment holes in the lower right side.
13 Jul 2013 (2.5 hours, total time to date: 763.0 hours)
Marked the trim line to allow 0.5(-) gap between the stabilizer & elevator flanges on the lower stabilizer skin. I need this to be able to install the hinge bolts - the gap is enlarged when the elevator is moved up or down (bottom or top). Turned over the stab/elevator & drilled the attachment holes in the upper tips. Then, marked the stab skin trim line on the top.
I then removed the elevator skins so that I could also remove the elevator spar hinge bolts (put the stabilizer away for the time being). Measured the location for the last rivet on the skin tips (as mentioned yesterday) & replaced the skins on the elevator spar. I marked & drilled the aft rivet holes on the upper/lower sides on both ends of the elevator. As the picture shows, I offset the aft rivet holes for clearance (not much room in there!).
I then removed the elevator skins so that I could also remove the elevator spar hinge bolts (put the stabilizer away for the time being). Measured the location for the last rivet on the skin tips (as mentioned yesterday) & replaced the skins on the elevator spar. I marked & drilled the aft rivet holes on the upper/lower sides on both ends of the elevator. As the picture shows, I offset the aft rivet holes for clearance (not much room in there!).
14 Jul 2013 (3 hours, total time to date: 766.0 hours)
Marked the locations for the elevator skin cut-outs around the outboard hinge bolts. As I did for the rudder, I will make one side just large enough to clear the hinge bracket for looks and lower drag (mostly for looks ;-) ). Therefore, I'll put the smaller cut-out on the top. I removed the skins (one at a time), and made the cuts using a small cut-off wheel and a 1/4 in. sanding drum with my Dremel tool. I finished the cut-outs using fine sand paper and scotch brite. I ended up with a few iterations for the smaller cut. Once I put the skin back, it was easy to see whether the clearance was adequate. While I was at it, I cut off & finished the end of each tip rib to clear the two offset rivet holes for the tip attach strips along the trailing edge. Once finished, I put the skins back on the elevator.
Then, I went back to the rudder and started fitting the fiberglass bottom. I clecoed the tail wheel steering arms back in place & marked the locations to cut out openings for the fitting. I made the initial rough cuts with my band saw, but quickly switched to using the old, trusty Dremel tool. I finished the cut-outs with #60 sand paper. The part fits much better once the cut-out is finished - due to the radius at the bottom of the rudder spar. I'll drill the attachment holes for the fiberglass after the skin is riveted in place (less chance of any movement of the frame).
Then, I went back to the rudder and started fitting the fiberglass bottom. I clecoed the tail wheel steering arms back in place & marked the locations to cut out openings for the fitting. I made the initial rough cuts with my band saw, but quickly switched to using the old, trusty Dremel tool. I finished the cut-outs with #60 sand paper. The part fits much better once the cut-out is finished - due to the radius at the bottom of the rudder spar. I'll drill the attachment holes for the fiberglass after the skin is riveted in place (less chance of any movement of the frame).
15 Jul 2013 (2 hours, total time to date: 768.0 hours)
Trimmed the stabilizer trailing edge skins & adjusted the fit of the outboard hinge fittings. I removed the outboard hinge fittings and added a little more to the bend angle so that the hinge bearing would slide in easier. I needed to remove the fittings anyway to use my cut-off wheel to make the initial trim cuts to the skins. I cleaned up the trim lines with a sanding disk, my Permagrit hand sander, finer sand paper, and finally a scotch brite pad.
16 Jul 2013 (1 hour, total time to date: 769.0 hours)
Drilled out the rudder skin attachment holes to 1/8 in. (seems to work out well after dimpling). Drilled in 2 steps (#33, then 1/8).
17 Jul 2013 (2 hours, total time to date: 771.0 hours)
Removed the rudder skin & de-burred the attachment holes. Did some light finishing work with scotch brite. Dimpled the holes with the pneumatic squeezer (a few locations had to be done with the vice grip dimpler). I did the dimpling in stages so I could dimple the skin directly on the frame (checking to see if this helps keep the holes in better alignment for riveting).
18 Jul 2013 (1 hour, total time to date: 772.0 hours)
Replaced the rudder on the fin. Laid out and drilled the pilot attachment holes for the rudder tips. I need to install the tip attachment nut plates before I rivet the skin to the rudder frame. There is not enough clearance near the trailing edge, so I will need to open the skin a bit to get the squeezer in there. The aft nut plates are staggered 1/4 inch for clearance - I used 2.125 spacing on the left & 2 on the right side so the spacing was even on each side.
19 Jul 2013 (4 hours, total time to date: 776.0 hours)
Removed the rudder from the fin & drilled out the rudder tip attach holes to #28 (for the #6 screws). I still haven't purchased nut plate template tools, so I simply use the nut plate itself as a drilling guide. Because of the tight fit at the aft end, I used a scrap piece of 2x4 to prop open the skin enough to get a screw (inside) through the hole to the nut plate (outside) with an offset screw driver. I used 2 washers so I didn't need to drive the 1/4 long screw completely through the nut plate. Drilled the nut plate satellite holes, removed the nut plates, de-burred, & finished the holes. I de-greased the inside of the skin (along the nut plate line), and applied a thin coat of primer. Installed the nut plates on the aft two holes on each side using my pneumatic squeezer with the no hole yoke. I decided to use NAS1097 -3-3.5 flush heads because the nut plates are not suited to be C/S. I carefully and lightly C/S the skin and the rivets are slightly proud. The skin is only 0.020, so there is not a lot of room, but still better than trying to dimple and get the nut plates to sit flush on the inside. I screwed up one rivet - the head lifted off the skin. After drilling that one out, I decided it was time for the "magic" scotch tape trick to hole the head on the skin. I held off on the forward holes because I will have room inside after attaching the skin, and the nut plate blocks access to the 2 -3 attach holes in the skin/tip rib. I then drilled out the tail wheel steering arm attach holes to 3/16 * bolted it to the lower spar. Finally, I scuffed up the mating surfaces of the aft tip rib/skin since I'll be using T-88 epoxy (no way to reach further back than shown with my squeezer). Also, I de-greased & lightly primed the inside of the skin (and outside of the lower rib) along the frame rivet lines.
20 Jul 2013 (2 hours, total time to date: 778.0 hours)
Epoxied the trailing edge of the rudder tip rib/skin and installed the tip rivets so that I could use the wood skin clamps to hold the skin tightly against the rib while the epoxy cured. It looks like I'll need to replace a couple of these rivets, but will take care of that later.
While that was curing, I decided to tackle the elevator trim tab control arm. The problem I have is how to attach the control arm to the trim tab. The drawing indicates riveting the arm, but I have no idea how to do that when there is no way to get inside the trim tab. The ends are bent to wrap over each other. I think the best way for me to go is to use #6 machine screws and nut plates. I can install the nut plates on the inner tab, then drill the screw holes through the other tab after I know where the holes will align. I laid out the position of the nut plates to provide adequate spacing and edge distance. I needed to fabricate my own control arm (the one on the left) to provide the edge distance. I marked the location of the holes in the control arm & drilled the #40 pilot holes accurately on my drill press. I then clamped the arm in place on the inner tab and match drilled the pilot holes. If I ever need to replace the control arm, this will make things much easier.
While that was curing, I decided to tackle the elevator trim tab control arm. The problem I have is how to attach the control arm to the trim tab. The drawing indicates riveting the arm, but I have no idea how to do that when there is no way to get inside the trim tab. The ends are bent to wrap over each other. I think the best way for me to go is to use #6 machine screws and nut plates. I can install the nut plates on the inner tab, then drill the screw holes through the other tab after I know where the holes will align. I laid out the position of the nut plates to provide adequate spacing and edge distance. I needed to fabricate my own control arm (the one on the left) to provide the edge distance. I marked the location of the holes in the control arm & drilled the #40 pilot holes accurately on my drill press. I then clamped the arm in place on the inner tab and match drilled the pilot holes. If I ever need to replace the control arm, this will make things much easier.
21 Jul 2013 (4 hours, total time to date: 782.0 hours)
Riveted the rudder skin to the frame. It looks like dimpling the skin on the frame is a good way to go whenever possible. The shop heads look a lot better and the dimples hold up well. When the holes aren't aligned exactly, I've found that one side of the dimple will collapse when the rivets are set. I went back and drilled out all 4 of the -3 rivets I installed in the tip rib yesterday. I tried to replace them with new -3s, but they would not set without bending. I'm guessing that it is because I had to dimple those holes with my vice grip dimpler, and they did not nest perfectly. One hole had a damaged dimple (one side collapsed), and the shop head would split every time. I ended up drilling them all out to 1/8, filing down/finishing the sharp edges, final drilling to #30, and installed NAS1097-4s. That worked out well.
Replaced the rudder bottom and laid out the fastener positions along the bottom rib.
Replaced the rudder bottom and laid out the fastener positions along the bottom rib.
22 Jul 2013 (2 hours, total time to date: 784.0 hours)
Drilled all the pilot attachment holes for the rudder fiberglass bottom to #40, removed the bottom, cleared out the shavings, re-attached, then went back and drilled out to #30. Removed every other cleco & drilled the odd holes to #28 in preparation to install the nut plates. I suppose I could have done them all, but with so many (7 on each side), I decided to install the nut plates in two stages to minimize any chance of the holes shifting. I'm using the same method to install the nut plates as I did on the tip. I needed to make a template from some scrap 0.040 sheet to drill the nut plate holes for the two holes at the end of the rib (not enough room inside for the offset screw driver). Drilled out & finished the nut plate attach holes at 8/14 locations.
23 Jul 2013 (2 hours, total time to date: 786.0 hours)
De-burred, finished, de-greased, & primed the 8 nut plate and attach holes. Installed the 8 nut plates, then replaced the rudder bottom. I drilled out the remaining 6 attachment holes to #28, removed the bottom, & drilled out the nut plate attachment holes. Finally, I cleaned up the new holes, de-greased, & primed the inside mating surfaces in preparation to install the nut plates.
24 Jul 2013 (1 hour, total time to date: 787.0 hours)
Installed the last 6 nut plates along the bottom rudder rib. Lightly finished the nut plate installation with sand paper and scotch brite to smooth over the proud edges of the nut plate attach rivets. Replaced the rudder bottom and attached the rudder to the fin so I could admire the fit :-). I still need to install a few nut plates along the lower steel rudder flange.
25 Jul 2013 (1 hour, total time to date: 788.0 hours)
Laid out & drilled #40 lower rudder fairing attachment holes along the bottom right side of the rudder spar. Also measured & marked the locations for the holes in the left side.
26 Jul 2013 (3 hours, total time to date: 791.0 hours)
Drilled out the attachment holes on the left side of the lower steel rudder spar flange. Installed the nut plates on the left side. It took a lot longer than I expected. The curvature made it a bit more challenging - I ended up replacing a few of the nut plate rivets (more than once) until I was satisfied.
27 Jul 2013 (4 hours, total time to date: 795.0 hours)
Finished construction work on the rudder! Installed the nut plates on the right side of the lower rudder spar. I used the standard squeezer yoke with large flat dies - it worked much better. I went back and replaced two more nut plate rivets on the left side.
Started work on the elevator trim tab fit-up. I trimmed/finished the piano hinge. Cut out a 0.032 doubler to beef up the control arm attachment to the trim tab & epoxied the doubler to the inside of the tab flange. While this was curing, I trimmed/finished the trim tab spar & bent the end tabs to fin inside the elevator.
Started work on the elevator trim tab fit-up. I trimmed/finished the piano hinge. Cut out a 0.032 doubler to beef up the control arm attachment to the trim tab & epoxied the doubler to the inside of the tab flange. While this was curing, I trimmed/finished the trim tab spar & bent the end tabs to fin inside the elevator.
28 Jul 2013 (5 hours, total time to date: 800.0 hours)
Installed the nut plates for the trim tab control arm & used my seaming tool to tighten the bend in the trim tab to close it up. Some additional minor bending was needed to keep the edge tabs flush. I also had to enlarge the holes in the outside tab for control arm machine screw clearance. Actually, I had to swap what have been the inside tab because is was not wide enough to provide any real edge distance for any attachment holes. For the record, I also epoxied a 0.032 doubler on the inside of the inner tab for more stiffness/stability at the control arm attach point. You can see it in the photo if you look carefully.
I laid out the attachment holes for the trim tab hinge/elevator skin/spar. I decided to use a 1 inch spacing - works well with the 0.5 inch hinge lugs. As I was checking the spar fit, I noticed that the tapered height wasn't adequate to prevent the skin from pulling inward. I spent a lot of time re-working the spar to open the flanges and increase the bend radius enough to make it fit properly. The flanges need to be bent more than 90 degrees to follow the taper of the skin toward the trailing edge, so the web must be wider than the open end. The part came with 5/8 + in. flanges, so there was enough material for the adjustment. I used some scrap 1/4 inch plywood and cut out a tapered form just slightly wider than the inside of the spar. Sanded the inside edges for a good radius, & used it to help re-work the part - lots of trial and error. It seems to fit much better now.
I laid out the attachment holes for the trim tab hinge/elevator skin/spar. I decided to use a 1 inch spacing - works well with the 0.5 inch hinge lugs. As I was checking the spar fit, I noticed that the tapered height wasn't adequate to prevent the skin from pulling inward. I spent a lot of time re-working the spar to open the flanges and increase the bend radius enough to make it fit properly. The flanges need to be bent more than 90 degrees to follow the taper of the skin toward the trailing edge, so the web must be wider than the open end. The part came with 5/8 + in. flanges, so there was enough material for the adjustment. I used some scrap 1/4 inch plywood and cut out a tapered form just slightly wider than the inside of the spar. Sanded the inside edges for a good radius, & used it to help re-work the part - lots of trial and error. It seems to fit much better now.
29 Jul 2013 (1 hour, total time to date: 801.0 hours)
I decided to epoxy the outboard end of the trim tab closed. I thought it might minimize the chance that the outside tab would ever catch on the elevator skin and it will stiffen up the tab as well. I prepared the surfaces, applied the T-88, clamped the flat face of the tab on the work table under a straight 2x4 (to maintain the alignment of the tab), and applied moderate pressure to the end tabs with a long clamp. I also used some duct tape wrapped tightly around the edge. While this was curing, I drilled out #41 pilot holes along the trim tab hinge line.
30 Jul 2013 (3 hours, total time to date: 804.0 hours)
Turned over the elevator, laid out, & drilled the #41 pilot attach holes along the bottom of the trim tab spar. I used a 1.375 in. spacing to match the hole spacing used in the stiffeners. I think I'll use some epoxy along the bottom as well since I expect the cavity to generate some acoustic vibration.
Man, getting the trim tab all lined up was more work than I thought it would be. I turned the elevator back over, and started fitting the tab in place. The challenge is to get the gap right (3/32 - 1/8), watch the edge distances/alignment along the hinge line, and probably most importantly - make sure the trailing edge lines up with the elevator. Getting one is easy. Getting two is not bad, but getting all three requires some patience! Also, for any prospective builders, this is one of many cases where you really want to be sure you check things as you go. The kit part is well done in general, but there are a lot of opportunities for foul ups. Especially the cut out in the elevator. Measure many times and leave a little material for adjustments if needed. Enough of that...... After many tweaks and some small compromises, I got her all fit up. As usual, I've got some polishing to do.
Man, getting the trim tab all lined up was more work than I thought it would be. I turned the elevator back over, and started fitting the tab in place. The challenge is to get the gap right (3/32 - 1/8), watch the edge distances/alignment along the hinge line, and probably most importantly - make sure the trailing edge lines up with the elevator. Getting one is easy. Getting two is not bad, but getting all three requires some patience! Also, for any prospective builders, this is one of many cases where you really want to be sure you check things as you go. The kit part is well done in general, but there are a lot of opportunities for foul ups. Especially the cut out in the elevator. Measure many times and leave a little material for adjustments if needed. Enough of that...... After many tweaks and some small compromises, I got her all fit up. As usual, I've got some polishing to do.
31 Jul 2013 (2 hours, total time to date: 806.0 hours)
Removed the trim tab & prepared to attach the elevator to the stabilizer & check the alignment required for the elevator tips. The hinge brackets on the stabilizer rib were not bent to 90 degrees, and as a result, the elevator hinge bearings would not easily (understatement) slide in place (you need to have approx. 0.44 inch clearance). I removed each fitting, increased the bend slightly between some solid pieces of oak clamped in a bench vise (light hammer strikes on another piece of oak). After a few attempts, the fit was reasonable. I then used 3/16 bolts (no nuts) to temporarily attach the elevator to the stabilizer & placed the assembly on my work table (on my padded spacers). I laid out the fiberglass tips to check the alignment, did some minor trimming/finishing work on the attachment tabs, and laid out the fastener pattern on the bottom of each rudder tip. I am using a spacing of 2 1/32 in the bottom & will use 2 1/4 on the tip to provide some offset for clearance between the aft nut plates.
1 Aug 2013 (1 hour, total time to date: 807.0 hours)
Drilled the #41 pilot attach holes on the bottom elevator tips. Turned the assembly (stab/elevator), marked, & drilled the pilot attach holes along the top of the tips. I removed the elevator from the stabilizer, did a little more trimming/finishing on the stabilizer tip attach tabs, & returned the stabilizer to it's stand for storage.
2 Aug 2013 Forward Fuselage Kit Arrived!
I can't log any hours for today since I needed to start unpacking and getting all of the parts squared away. Everything was looking great....until I got to the bottom of the box. No big deal, just a bit disappointing. You can see what happened sometime during the shipping process. It really wasn't obvious from the outside. Evidently the forks slid between the bottom and the side. Some of the wood was broken, but it was mostly on the inside that the damage was of any note.
I filed a claim, but will have to wait until next week to get things going with the shipping company. Again, no big deal, I've got plenty of other work to do.
I filed a claim, but will have to wait until next week to get things going with the shipping company. Again, no big deal, I've got plenty of other work to do.
3 Aug 2013 (2 hours, total time to date: 809.0 hours)
Drilled out the pilot elevator tip attach holes to #28 in 2 steps in preparation to install the nut plates. Also drilled out the elevator skin attach holes to 1/8 in. I drilled these in 2 steps as well. The holes aft of the spar along the tip ribs will remain sized for -3 rivets as well as the holes along the trim tab hinge and lower trim tab spar line. However, the holes along the root ribs will all be sized for -4 rivets.
4 Aug 2013 (3.5 hours, total time to date: 812.5 hours)
Labeled each elevator tip attach strip for ID purposes & removed them. Used nut plates as drilling templates (as usual) & drilled the attach holes in each strip. Removed the right elevator skin & de-burred all of the holes. Dimpled the -3 holes along the attach strips and both tip ribs. I used a 2-step process since I've had good luck setting rivets when I dimple the skin over a pre-dimpled flange (forces the dimples to be aligned). Did the same with the -4 holes at the LE. I dimpled two of the holes in the spar nearest the tip using my trusty vice grip dimpler (I have no other way to reach in those tight spots). The attach strips need to be installed in the skin before attaching the skin to the spar because I have to open the skin to reach the aft rivets. There is a relatively wide gap between the aft rivets and the next rivet that attaches through the rip rib. This is where the T-88 epoxy comes in handy again. I prepared the tab/skin mating surfaces with rough scotch brite, taped off the areas to be bonded, used finer scotch brite, de-greased the parts, & applied a light coat of primer where the attachment will be with rivets only. Removed the tape, let the primer cure, and de-greased the areas to be bonded. Did the following for each tab: Applied the epoxy to the tab, clecoed the tab in place, used cleco clamps to hold the end of the tab, added a pair of "fingers" upstream of the aft attach hole, propped the skin open, and installed the aft rivet. The part about adding a pair of fingers came after I learned the hard way that they are needed to hold the tab down with the skin is open. I had some trouble getting the first rivet to seat flush because of this problem. After drilling out 2 and enlarging the hole, I decided more clamping was needed. So, the bottom side has an "oops" rivet. Finally, I dimpled every other hole in the right elevator spar & root rib flanges while waiting for the epoxy to cure.
5 Aug 2013 (3.5 hours, total time to date: 816.0 hours)
Replaced the right elevator skin & dimpled the holes over the previously dimpled holes in the frame with my pneumatic squeezer. Removed the skin again, and dimpled the remaining holes in the frame and repeated the process. There were still a few holes that had to be done with the vice grip dimpler. Prepared the tip attach tabs and inside of the skin for bonding/priming. The bonding was only along the trailing edge of the tip rib. Finally (this part took just over 2 hours), replaced the right skin for the last time, applied epoxy to the tip rib, & clecoed it in place. Used my no hole squeezer yoke to install the 4 rivets in the tip rib. The problem was the limited access & I had trouble with the -3 rivets. The first 2 split - it sure seems like the dimple alignment is at least partially to blame for this. The vice grip dimpler is certainly not the best tool, but I had no other choice. After drilling out 4 rivets (2 in each hole on one side), I decided that I might as well drill out the holes, filed/finished the inside edges, and install 1097 rivets. This worked well. I just went straight to the 1097s for the other side......
6 Aug 2013 (2 hours, total time to date: 818.0 hours)
Installed the remaining 4 nut plates on the right elevator tip attach strip. Also, installed all of the rivets along the top and bottom of the right elevator spar. Near the tip, I had to use the no hole yoke. That has turned out to be a "must have" for building the MM - at least as far as I'm concerned.
7 Aug 2013 (2 hours, total time to date: 820.0 hours)
Installed the rivets along the right root rib line (top & bottom) and lightly polished the skin. Then, I removed the left elevator skin and de-burred all of the attachment holes on the skin, frame, & trim tab spar.
8 Aug 2013 (2 hours, total time to date: 822.0 hours)
Dimpled the attachment holes along the left elevator tip & tip attach strips. Finished the mating surfaces, de-greased, masked off the areas to be bonded, & applied a light coat of primer. Removed the tape & waited for the primer to cure. Applied epoxy to the attach strips, clecoed & clamped them in place (one at a time), propped the skin open enough to squeeze the aft rivets. Cleaned up the epoxy around the outside edges, replaced the clamps, & set the skin aside to cure. Then I laid out the locations for the adel clamps on the left root rib to secure the trim tab control wire tube. This is something I wish I had thought to do before riveting the root rib to the steel fitting. Now, I won't be able to remove/de-bur the holes for the nut plate that goes in that location. I'll have to clamp the area as tightly as possible to keep shavings out of the interface.
9 Aug 2013 (2 hours, total time to date: 824.0 hours)
I cut a 2.5 x 0.5(-) strip from some scrap 0.125 thick aluminum to clamp against the left elevator root rib web to hold the web tightly against the steel attach tab while I drill out the Adel clamp attachment hole for the trim tab control cable. I drilled a #40 pilot hole in the strip to use as a drilling guide & clamped it into position. The hole(s) have to be drilled from the outside of the rib since there is not enough clearance between the left and right root ribs. I drilled the attachment hole out to 3/16 in progressive steps (#40, #33, #30, #28, #21, #19, & 3/16). I was very concerned about getting steel chips between the rib and attachment tab, but the hole looked great! It took a lot of time, so I'm glad it was worth it. Then, I removed the strip & used a nut plate as a drilling guide to drill out the nut plate attachment hole locations. I attached the strip back on the rib with a #10 machine screw and a nut on the other side, clamped the outside edges of the strip, & drilled out the nut plate attachment holes. Again, this seemed to work very well to keep chips out of the interface. Then, I drilled out the aft hole for the second Adel clamp (6 inches from the elevator spar) & used a nut plate as a drilling guide for the attachment holes. Finally, I de-burred the holes, used some fine scotch brite on the rib web & applied a light coat of primer.
10 Aug 2013 (1.5 hours, total time to date: 825.5 hours)
I used a -3 C/S bit by hand to prepare the nut plate attach holes for installation. There was no other way for me to get between the root ribs & I really didn't want to remove the bolts attaching the spar halves. In retrospect, it would have probably been a better idea to remove the bolts. Anyway, I installed the nut plates with some difficulty because of the angle of the rib wrt the spar (see my earlier comment about removing the bolts). Hind sight really is 20/20 - at least.
11 Aug 2013 (4 hours, total time to date: 829.5 hours)
Removed the elevator spar bolts connecting the 2 halves of the elevator so I could work on the left side by itself and have much better access to the root rib. As I wrote yesterday, I should have done this in the first place. You just need to be a little more careful to pay attention to what is up/down, but at this stage, there is no problem. Dimpled all of the attachment holes as was done on the right side. It's a longer process, but I think it really makes a difference. Additional work is required because of the trim tab hinge and spar. I removed the hinge pin & C/S the holes in the side that connects to the elevator. I decided to use a #6 C/S machine screw at the aft hole on the upper side of the root rib. This will provide a removable attachment point to secure the hinge pin so that the trim tab can be easily removed, and the hinge pin can be replaced in the future if necessary. I drilled out the hole to #28, dimpled the upper hole in the skin, & C/S the hole in the hinge. As always, it takes a few iterations to get the C/S depth correct. Finally, I prepared the attach tab for installation of the aft nut plate. I also de-greased and applied primer along the rivet lines on the inside of the skin.
12 Aug 2013 (2 hours, total time to date: 831.5 hours)
Installed the aft nut plates on the top & bottom of the left elevator. It was not easy to keep the furthest aft rivet straight. I think I had to drill out 8 of them in total. I'm getting pretty good at it by now. I was using 1097's, but finally switched to the standard -3s for the two aft rivets. I had to C/S a little deeper, but it was a lot easier to get them to squeeze straight with the skin propped open. Got each the first time. I got a little carried away while dimpling the trim tab spar and forgot that I don't want dimples in the top flange (since the hinge is C/S). So, I carefully & progressively squeezed the holes flat and fabricated a 0.020 backup strip that I will bond and rivet to the inside of the flange. I match drilled the attachment holes and finished the part.
13 Aug 2013 (2.5 hours, total time to date: 834.0 hours)
Finished, de-greased, & applied primer to the mating surfaces of the trim tab spar/skin/backing plate. Test fit the assembly - looked good. Mixed up the epoxy & applied it to the lower inside skin and the lower surface of the trim tab spar. Clecoed the spar back in place & riveted the lower surface. This was another time consuming process. It turned out that the -3 length 3/32 rivets were a little too short and the -3.5's were a little too long. I tried cutting the 3.5s down, but had a hard time squeezing them straight. Two split - one of them badly. Since the epoxy was on the clock, I didn't want to remove more than was absolutely necessary. I ended up using some -3 length rivets as a temporary solution. As long as the rivets were tight, I knew I could replace them later. The bad one had to be replaced & I used a 1097-4. It was a bit of a mess, but I finally got it done (for now).
14 Aug 2013 (2 hours, total time to date: 836.0 hours)
Prepared the mating surfaces of the backing strip and trim tab spar (scotch brite & de-greaser), applied epoxy to the surfaces, & clecoed the backing plate in place for attachment of the upper skin/hinge/spar. I quickly realized that although my no hole squeezer yoke would reach inside the channel, the hinge lugs prevented the rivets from being fully set. I could use a small bucking bar in the root area, but only for a short distance along the span. I decided to grind down/polish the nose of a 3 inch yoke since the height of the flush die would clear the hinge lugs. This worked well, but I hope that I haven't ruined the yoke for larger rivets. If so, it was still well worth it.
15 Aug 2013 (2 hours, total time to date: 838.0 hours)
Removed & replaced the -3 rivets on the bottom of the trim tab spar with 1097-4-3.5s. After drilling out each rivet, I carefully filed/finished the bottom of the dimple to get rid of sharp edges and "re-flatten" the rim. I'm getting pretty good at drilling out rivets - I guess that's a good thing.
16 Aug 2013 (2 hours, total time to date: 840.0 hours)
De-greased the bonding surfaces of the left tip rib & inside of the skin, applied the epoxy, clecoed the rib in place, & installed 1097-4s in the 4 rib attachment holes. I used 2 long nose cleco clamps to apply pressure to the rib flanges aft of the second rivet. I couldn't have installed rivets any further aft - I had just enough clearance for the no hole yoke. I think my method will work well to keep the tip very secure and provide very good torsional rigidity for the elevator. To finish work for the day, I riveted all but 3 of the attachment holes along the lower left elevator spar. It was a good stopping point since I will switch back to the no hole yoke for the last 3 near the tip. By the way, for anyone interested, my newly modified 3 inch squeezer yoke worked just fine for the -4s. Saved me some $$.
17 Aug 2013 (2 hours, total time to date: 842.0 hours)
Finished riveting the bottom of the left skin & moved on to the top side. The prep work made things go very smoothly - no problems at all. Very nice shop heads. Then, I finished the left side by installing the last 4 nut plates for the fiberglass tips.
18 Aug 2013 (2 hours, total time to date: 844.0 hours)
Removed the piano hinge from the trim tab & de-burred the holes. C/S the holes on the hinge, replaced the hinge in the trim tab, & carefully dimpled the upper tab skin using my pneumatic squeezer. Actually, I did this in 2 stages (every other hole), and set the squeezer to allow some clearance for the thickness of the hinge. I only wanted to dimple the upper tab skin inside the hinge C/S. I then riveted the hinge/tab skin & returned the trim tab to the elevator by installing the hinge pin. I marked the location to bend the hinge pin, drilled a #40 hole in some scrap oak 1x4 to hold the pin for bending. Later, I will cut out a piece of hinge stock to secure the bent pin, and attach the flange through the #6 machine screw hole at the aft/inside edge of the elevator. Finally, I re-assembled the elevator, wiped it down with acetone to clean it up, & installed the fiberglass tips. The elevator is essentially finished!
19 Aug 2013 (1 hour, total time to date: 845.0 hours)
Shifting gears to start working on the fuselage again. I had to run a new C/L wire along the fuselage jig - it was broken several months ago (got stepped on :-) ). I also ran a new A/C C/L wire and did a quick check to be sure nothing has moved. Took a few measurements for the front post that I will build tomorrow to "permanently" secure the A/C C/L.
20 Aug 2013 (1.5 hours, total time to date: 846.5 hours)
Cut the 1x4s for the front C/L post. Shot a level line with my laser level to find the location of the C/L hole in the front post. It will give me a very good starting point before I make the final adjustments to the post. Started assembling the post to make it very secure. I will rig a spring system to hold the wire tight. The temporary post in the middle is just there to help mark the C/L location in space.
21 Aug 2013 (1.5 hours, total time to date: 848.0 hours)
Fabricated an alignment plate for the C/L wire. I used a #6 nut plate as a wire guide and attached it to a scrap piece of 0.040 aluminum. I'll feed the wire through the nut plate and make the required adjustments to get the wire in place. Once finished, I can secure the plate to the forward post. I attached a steel strap to a piece of 1x4 to hold a spring in position to provide tension to the C/L wire. Removed the center alignment post. Finally, I added some reinforcement (2x4) on the inside of the front 1x6 on the fuselage jig and installed lag bolts on each side of the BH73.75 support.
22 Aug 2013 (1 hour, total time to date: 849.0 hours)
Got up early and checked the alignment of the C/L wire. I double checked the distance to the rear spar attach holes, the lateral alignment, and the distance from the top of BH99.35 to the 99.35 plane. Made the fine adjustments to the position of the alignment plate. Everything looked good, although I think you could go crazy checking and re-checking everything (when is anything good enough??). I screwed the alignment plate in place as well as the tension spring support. Now, it's time to get BH73.75 mounted in the jig.
23 Aug 2013 (2 hours, total time to date: 851.0 hours)
Well, I decided to check the alignment again .... I guess I am going nuts. The plans call for the placement of the wing attach holes in BH73.75 to 1/64 of an inch. I can't help thinking ....seriously??? I'll certainly give it my best shot, but my fine sharpy marker is about 1/64 of an inch, and I'll be drilling into plywood. In any case, this got me thinking that I better check the alignment again. I used some clear tubing and ran a water level between the C/L at BH177.5 and the front post. It indicated that I should raise the wire at the post by approx. 1/10th of an inch. I also double checked the stabilizer attach points (they appear to be level), and the rear spar attach holes. I then ran the water level tubing between BH99.35 and the front post and got a second opinion with my laser level. The wire needed to come up a little, so I made another wire guide to mount on the back of the front post for the final adjustment. Finally, I cut out a large blank out of birch plywood to be used to mount BH73.75 in the fuselage jig.
By the way, for anyone interested. The clear tubing is very helpful when you need to check for level over a long distance, but I noticed that you need to be careful about a few things. First, try to keep the tubing vertical at the points you are checking. Second, if you have excess tubing, be careful to check for any water blocking the tubing downstream of either point. I used a tube with an I.D. of 1/4 inch and got a few false indications. It seemed to help if I gently blew into the tube to get the water to oscillate before settling to the level points. Of course, YMMV.
By the way, for anyone interested. The clear tubing is very helpful when you need to check for level over a long distance, but I noticed that you need to be careful about a few things. First, try to keep the tubing vertical at the points you are checking. Second, if you have excess tubing, be careful to check for any water blocking the tubing downstream of either point. I used a tube with an I.D. of 1/4 inch and got a few false indications. It seemed to help if I gently blew into the tube to get the water to oscillate before settling to the level points. Of course, YMMV.
24 Aug 2013 (2 hours, total time to date: 853.0 hours)
Another little detour. I put off installing "holding rivets" for the tail cone skin at BH99.35 - I guess I was hoping I would come up with a better idea. Well, I didn't, so it seemed like a good time to get it done. Before I align the fixture in the jig for BH73.75, I want to have everything done that might possibly move. Also, thinking ahead to skinning the center fuselage when access will be much more limited, I installed 1097-3-3's as holding rivets. They are pretty easy to remove and don't require a C/S to sit flush enough to allow the center skin to be fitted over the tail cone skin. I installed one above the upper longeron cutout - just because they hold the skin tighter than a cleco. When the skin is finally riveted, it will be pulled tighter than the clecos, and I want the transition to be as smooth as possible. I spaced the rivets approx. 6 inches apart (worked out to be less than 6 for the most part), but the existing pilot holes in the flange of BH99.35 dictate what can actually be done. I tried to place them where I wasn't going to install the final rivets, so I wouldn't have to remove the skin/BH multiple times to de-burr/dimple. I also installed a few as needed to hold the skin around the bottom bend and rear spar carry thru. One of my concerns is/has been that it will be difficult to drill out rivets on the bottom of the BH because of the limited space between the jig and the bottom skin. That's why I increased the height of the posts by 4 inches. Even so, I may have to grind/drill off the shop heads from the top. There will be no way to install rivets in the bottom corner (because of the rear spar attach posts) when the center skin is installed. However, I can rivet the tail cone skin to the BH prior to replacing the center skin at those spots. I'll install the final rivets on either side of the corners through both skins. As I was deciding where to install the holding rivets, I added one more rivet location on each side of the bottom that made sense for symmetry and strength. I drilled these out to #41 though the existing pilot holes in the BH flange tabs. Better to do this now to make it easier when the center skin is being fitted. Now, all of the holes are ready to be drilled through the center skin from the inside. Finally, I carefully cut and removed some of the Masonite (and the contoured 1x2s alone the BH web) to a point above the upper longeron cut-outs in the web of BH99.35. I needed the Masonite (and the short pieces of 1x2) to stabilize the BH while I was building the tail cone. No reason to completely remove it yet.
25 Aug 2013 (3 hours, total time to date: 856.0 hours)
One more addition to the fuselage jig before starting work on the support for BH73.75. I attached a 2x4 along the forward lower edge of the 2x6 cross member for BH73.75, and 6.5 inch pieces of 2x4 on each side forward of the cross member. I cut out 2, 8 inch gussets to provide more support to the jig. I used the plywood I salvaged from the top of the shipping box from MA - you can see the remnant of the "This Side Up" that I thought would be a nice touch.
Then, I finally started working on the support for BH73.75. I laid out the C/L & cut the shoulder notches to fit inside the jig. I also cut a notch for the C/L wire and did some preliminary fitting work.
Then, I finally started working on the support for BH73.75. I laid out the C/L & cut the shoulder notches to fit inside the jig. I also cut a notch for the C/L wire and did some preliminary fitting work.
26 Aug 2013 (1 hour, total time to date: 857.0 hours)
The plans indicate that the thickness of the jig attachment for BH73.75 should be 0.75 in. However, the actual dimension of the parts are approx. 0.8 inches. I will need to make some slight adjustments to keep things snug (but not too snug). Today, I shimmed the shoulder cut-outs to align the center of the BH attach board, installed 2 temporary screws to hold the board in place, & clamped a nice straight piece of finished 1x2 across the horizontal A/C C/L (notched to accommodate the C/L wire). Made the necessary adjustments using my laser level & marked the horizontal C/L on the board.
27 Aug 2013 (1 hour, total time to date: 858.0 hours)
I looked at some pictures of other projects, and was reminded that the BHs may have a good C/L hole, and if so, I can use that to get around my 1/64th "issue." I learned the hard way that this is not always true (my tail cone BHs), so I called Chris and asked him about it. He thought that their were holes on the C/L, but of course, I should check it. When I took a closer look at my BH assembly, it was pretty clear that there are C/L holes (they are 1/8 in. dia.). The measurement looks good, so that is one less worry as far as getting the wing incidence set correctly.
All I did today was to laminate a scrap piece of my birch plywood with 2 pieces of 0.032 sheet & drill out the "permanent" attachment holes for the vertical support for BH73.75. I wanted to get the holes perpendicular to the face of the plywood, so I made a drilling guide from another scrap piece of 1x4. Tomorrow, I'll be able to check to see how "snug" the laminated plywood is in the wing attach lugs. Also, I'll drill a 9/16 hole through the laminate to check the bolt clearance. I can't simply run a drill bit through the wing attachment holes without scratching/enlarging the holes - they are nicely reamed and matched to the spars.
All I did today was to laminate a scrap piece of my birch plywood with 2 pieces of 0.032 sheet & drill out the "permanent" attachment holes for the vertical support for BH73.75. I wanted to get the holes perpendicular to the face of the plywood, so I made a drilling guide from another scrap piece of 1x4. Tomorrow, I'll be able to check to see how "snug" the laminated plywood is in the wing attach lugs. Also, I'll drill a 9/16 hole through the laminate to check the bolt clearance. I can't simply run a drill bit through the wing attachment holes without scratching/enlarging the holes - they are nicely reamed and matched to the spars.
28 Aug 2013 (2 hours, total time to date: 860.0 hours)
Checked my C/L one more time and verified that the top of BH99.35 is 6.25 in. aft of the vertical. Also, double checked the vertical and horizontal C/Ls on the jig support for BH73.75. I then removed the plywood & laid out the approximate position of BH73.75 (using the C/Ls marked on the face). There is not a lot of room for error between the bolt holes and the outside of the skin, so I wanted to get my cuts in the plywood as accurate as possible. I also marked the bottom edge of the BH on the plywood so I could determine the skin clearance when I make the cutout. The next thing I will do before laminating the areas around the bolt holes is to shim the plywood with washers to be vertical & take measurements of the exact longitudinal location of the board. I'll need this to decide on the thickness of the aluminum to use on each side to keep the BH at 73.75.
29 Aug 2013 (2 hours, total time to date: 862.0 hours)
I checked the vertical alignment of the support for BH73.75 & the top needs to move slightly aft, so I added 2 0.062 washers at the top attach bolts. This was too much (as I thought), so applying the "Goldilocks" method, I fabricated 2, 0.032 thick washers and tried again. This was just right - at least vertically. I then fabricated a measuring stick to check the inside distance between the support and BH99.35 (measured off of the rear spar doubler - or aft edge of the lower BH web) on each side to check the lateral alignment. This indicated that the left side of the support needs to move forward approx. 1/32. So, I removed the upper washer & sanded the left lower inside of the support to keep the support vertical. This seemed to work, but I will still need to make minor adjustments once I get the BH mounted on the support. I'd like to have at least 0.020 aluminum laminated on the rear face to improve the bearing strength & support for the hole cutter's pilot pin at the attachment holes.
30 Aug 2013 (2.5 hours, total time to date: 864.5 hours)
Traced the outline for the aluminum laminate doublers & transferred the pattern to a scrap piece of 0.062 sheet. Cut out & finished the pattern, then duplicated it on one more piece of 0.062 and 2 pieces of 0.020. I removed the plywood support & used a Skill Saw to make the final cut-out for BH73.75. Because of the added height, I was able to add a little more clearance below the skin line. I will need to reinforce the panel, but will do that once I get it all lined up. I prepared the "doublers" for bonding (sanding +-45 & de-greasing), mixed up a batch of epoxy, & bonded the doublers in place. I also drilled very small holes in the doublers and used wire brads to prevent any movement. Replaced the support in the jig & clamped the doublers to cure. I used wax paper to prevent the boards used to clamp the doublers from adhering.
31 Aug 2013 (1.5 hours, total time to date: 866.0 hours)
Removed the vertical support & used a Dremel tool to grind the brads flush to the surface of the aluminum doublers. Did a little light finishing work on the support and replaced it in the jig. Test fit the BH & made more adjustments to the support. I fabricated another "measuring stick" to measure the 25.6 inch distance between BH73.75 & BH99.35.
1 Sep 2013 (4 hours, total time to date: 870.0 hours)
A lot of time to accomplish what doesn't look like much....
Started work to get the final alignment done for BH73.75. Used the measuring sticks to check each side of the BH for lateral alignment. Removed the BH & support to make some very slight adjustments to the support & added 1x4 reinforcements to the front of the support (glue & screws). I had shimmed the shoulders of the support, so I installed the reinforcements to rest on the jig. Replaced the support & resumed work on the BH alignment. I used a straight 1x2 clamped across the horizontal C/L. Both the lower BH angle and the 1x2 looked great according to my laser level. I also measured the distance from the C/L wire to the C/L holes on each side of the BH (in my case, 10-26/32 inches to the edge of the wire). I then installed steel brackets on the front of the support and the jig. I cut 2 pieces of 1x2 to use as braces to hold the BH in place (fore & aft). The braces will also allow me to make fine adjustments to each side. The bottom of the support is nearly "perfect" laterally, but I'm seeing a little less than 0.01 difference at the wing attachment. The braces will allow me to correct that easily. Those measuring sticks really help a lot to get the inside measurements. I'll have to include a picture of them.
Started work to get the final alignment done for BH73.75. Used the measuring sticks to check each side of the BH for lateral alignment. Removed the BH & support to make some very slight adjustments to the support & added 1x4 reinforcements to the front of the support (glue & screws). I had shimmed the shoulders of the support, so I installed the reinforcements to rest on the jig. Replaced the support & resumed work on the BH alignment. I used a straight 1x2 clamped across the horizontal C/L. Both the lower BH angle and the 1x2 looked great according to my laser level. I also measured the distance from the C/L wire to the C/L holes on each side of the BH (in my case, 10-26/32 inches to the edge of the wire). I then installed steel brackets on the front of the support and the jig. I cut 2 pieces of 1x2 to use as braces to hold the BH in place (fore & aft). The braces will also allow me to make fine adjustments to each side. The bottom of the support is nearly "perfect" laterally, but I'm seeing a little less than 0.01 difference at the wing attachment. The braces will allow me to correct that easily. Those measuring sticks really help a lot to get the inside measurements. I'll have to include a picture of them.
2 Sep 2013 (5 hours, total time to date: 875.0 hours)
Kind of a long building day, but it's Labor Day, so I had a little more time....
Checked the alignment (yes, again), and moved BH73.75 slightly to the left. Of course, that meant that I had to re-level. Once satisfied, I made the adjustments to the braces to get 25.6 inches between the the rear spar doubler and the inside of the BH 73.75 web. I used the measuring stick shown in the picture above. Then, I fabricated several centering drilling guides to allow me to drill the attachment holes in the support for BH73.75. These holes can not be drilled with the BH in place or the attachment holes in the BH will be ruined. I decided to make the aluminum drilling guides to slip inside the lug holes and allow me to drill out the 1/8 dia. pilot holes for my hole cutter. It turned out that the 1 inch hole cutter produces a slug that is just slightly larger than 9/16. I laid out a cutting pattern on some scrap 1/8 thick 6061 angle stock and cut out 8 blanks. I machined the OD of the blanks by sliding the centered hole on the shank of a 1/8 drill bit between two 3/16 washers (helps keep the blank normal to the shank to minimize hole wear, and protects your fingers from some of the heat) and spinning them against my sanding disk. Once I was getting close to the final size, I switched to the scotchbrite wheel (a few of the finished blanks are shown in the picture above). It was important to stop and check the size often to get a good fit in the lug hole. I used a drilling guide in each side & used a flat piece of 1x2 with a 1/8 hole drilled on my drill press as a guide (held flat against the lug). I drilled the pilot holes from each side - hoping that would give me a better chance of getting a nice straight pilot hole. I drilled the bottom two holes first, removed the BH, & drilled out the holes with my hole cutter. The hole cutter centering pin worked nicely as a drilling guide since I had to drill the 9/16 holes with the support in place. I replaced the BH, installed 9/16 cap screws, and checked the alignment again - success! That was a great relief because I didn't have a better idea with the tools I have. Then I repeated the process with the upper holes. Now, the cap screws are slightly smaller than the AN9 bolts that will be used to attach the wing, but they are a nice, close hand fit in the BH lug. I was getting cocky, but the odds were not great that I'd get all 4 holes to fit perfectly with my method. However, I really didn't care that much once I knew the bottom 2 holes held the BH level & centered. After I cut the the upper holes, I de-greased/primed the aluminum doublers on the support (remember my comment about being cocky?). Well, the upper bolts would not go in by hand, and I was not going to force them. So, I removed the BH, and carefully ran a 9/16 drill bit through the upper holes in the support & touched up the primer :-). This enlarged the upper holes in the support enough for the bolts to fit nicely by hand when I replaced the BH.
Checked the alignment (yes, again), and moved BH73.75 slightly to the left. Of course, that meant that I had to re-level. Once satisfied, I made the adjustments to the braces to get 25.6 inches between the the rear spar doubler and the inside of the BH 73.75 web. I used the measuring stick shown in the picture above. Then, I fabricated several centering drilling guides to allow me to drill the attachment holes in the support for BH73.75. These holes can not be drilled with the BH in place or the attachment holes in the BH will be ruined. I decided to make the aluminum drilling guides to slip inside the lug holes and allow me to drill out the 1/8 dia. pilot holes for my hole cutter. It turned out that the 1 inch hole cutter produces a slug that is just slightly larger than 9/16. I laid out a cutting pattern on some scrap 1/8 thick 6061 angle stock and cut out 8 blanks. I machined the OD of the blanks by sliding the centered hole on the shank of a 1/8 drill bit between two 3/16 washers (helps keep the blank normal to the shank to minimize hole wear, and protects your fingers from some of the heat) and spinning them against my sanding disk. Once I was getting close to the final size, I switched to the scotchbrite wheel (a few of the finished blanks are shown in the picture above). It was important to stop and check the size often to get a good fit in the lug hole. I used a drilling guide in each side & used a flat piece of 1x2 with a 1/8 hole drilled on my drill press as a guide (held flat against the lug). I drilled the pilot holes from each side - hoping that would give me a better chance of getting a nice straight pilot hole. I drilled the bottom two holes first, removed the BH, & drilled out the holes with my hole cutter. The hole cutter centering pin worked nicely as a drilling guide since I had to drill the 9/16 holes with the support in place. I replaced the BH, installed 9/16 cap screws, and checked the alignment again - success! That was a great relief because I didn't have a better idea with the tools I have. Then I repeated the process with the upper holes. Now, the cap screws are slightly smaller than the AN9 bolts that will be used to attach the wing, but they are a nice, close hand fit in the BH lug. I was getting cocky, but the odds were not great that I'd get all 4 holes to fit perfectly with my method. However, I really didn't care that much once I knew the bottom 2 holes held the BH level & centered. After I cut the the upper holes, I de-greased/primed the aluminum doublers on the support (remember my comment about being cocky?). Well, the upper bolts would not go in by hand, and I was not going to force them. So, I removed the BH, and carefully ran a 9/16 drill bit through the upper holes in the support & touched up the primer :-). This enlarged the upper holes in the support enough for the bolts to fit nicely by hand when I replaced the BH.
3 Sep 2013 (0.5 hour, total time to date: 875.5 hours)
Didn't have much time today, but snugged up the cap screws, re-checked the fore/aft alignment on each side of BH73.75, & screwed the front braces to the fuselage jig.
4 Sep 2013 (1 hour, total time to date: 876.5 hours)
Fabricated a forming jig to use to bend the upper longerons & cut a piece of scrap 1/8 inch 2x2 aluminum angle down to 1x1 to practice the bending process. I tried using my bench vise, but it didn't work well. I'll try using a mallet and see how that goes tomorrow.
5 Sep 2013 (1 hour, total time to date: 877.5 hours)
I fabricated another tool to use with a mallet to form a bend in the angle stock. I used a piece of the scrap that I had cut from my larger angle stock to sandwich between two pieces of hard wood. I rounded the nose of one of the pieces of hard wood to rest inside the angle and also rounded the inside edge to accommodate the inside fillet radius of the angle. I drilled & bolted the tool together and gave it a try with the mallet. I can see that it will take patience (sometimes I'm lacking in that area :-)), but it looks like it will work.
6 Sep 2013 (3 hours, total time to date: 880.5 hours)
I decided to attach a piece of 1x1x0.062 angle across the horizontal C/L of BH73.75 with a notch at the C/L to provide a quick way to check to be sure that things haven't moved (at least in 2 of 3 planes). As I was fabricating the angle, I noticed that it appeared that the side flanges were not symmetric wrt the C/L. I nearly panicked since I measured everything off of the C/L holes in the BH. So, I checked everything again - especially the placement of the wing attach holes. I could only "eyeball" the location of the center of the hole wrt to the cap screw, but that looked OK. I finally decided that the flanges just aren't symmetric, and it isn't really a big deal. I checked the distance between the outside of each side of the BH and the projected extended line of the tail cone skin (at the longeron level), and they were as equal as I could measure. After all of that, I laid out the bend locations for the left & right longerons and made the bend in the left longeron (at BH99.35). It took some time, and I had to go back and take a little out and add a little where the longeron meets the end of the BH flange. I wanted to minimize the gap at the flange - the skin will make a turn right there. I found that the bend really occurs at the striking point, and keeping the location of the straight portion at the inside corner of the 2x4 in the bending jig was not really necessary (although it does guarantee to keep that area straight). I want the keep the bend at the edge of the BH flanges so that any gaps in the skin will be minimal. For the right side, I'll start bending with the line on the corner, then start moving it in a little as I go. BTW, the mallet was OK, but I ended up switching to a hand sledge - call me impatient, 6061-T6 is still pretty strong stuff..... :-) . Finally, I clamped/leveled the left longeron in place.
7 Sep 2013 (2.5 hours, total time to date: 883.0 hours)
I had a conversation with my good friend, Tom Dieters, about working the bend in the aluminum angle. He definitely put my mind at ease. I made the aft bend in the right longeron & clamped it in place. This one took less time, but I'm sure the number of hits were in the 3 digit range. Once I got close, I made several trial fits so that I wouldn't need to take any of the bend back out. It worked out very well. Then, I started work building a "box" using some scrap 2x6 lumber and 3/8 plywood to attach the forward posts for the firewall. The steel angle stock that I have is not quite long enough since I raised the A/P 4 inches higher than the plans indicate. The box will add more stability to the posts and will be square so that the post flange will be parallel to the firewall (the jig sides are slightly tapered per plans).
8 Sep 2013 (3 hours, total time to date: 886.0 hours)
I fabricated another measuring stick to measure the 23.75 in. distance from BH73.75 to the inside edge of the vertical post flanges. Then, I mounted the "box" on the front of the fuselage jig. The box is open to the rear and provides 9.5 inches of vertical attachment for the forward posts. I attached the box on the forward side after attaching 2x4 spacers to be flush with the front of the jig. The spacers are sandwiched between the box and another pair of 2x4s that tie the spacers to the front of the jig. I ran plumb lines down along each post & used the measuring stick to determine their approximate placement. I marked & drilled holes in the bottom of each post to attach to the box & to attach a 1x2 to maintain the lower lateral spacing of the posts. I cut the 1x2 to length, rounded the inside edges, verified the lower spacing, & match drilled the attachment holes through the wood. I used 3/16 bolts to attach the 1x2. Finally, I clamped the posts in place until I can continue the work.
I'll be traveling over the next week, so building will be on hold until I get back.
I'll be traveling over the next week, so building will be on hold until I get back.
14 Sep 2013 (1 hour, total time to date: 887.0 hours)
OK, back home and back to work. I didn't have a lot of time, but I wanted to do a little more work on the box support for the forward posts. However, I realized that I had drilled 3/16 attachment holes along the lower end of the steel posts. I removed the posts so that I could drill these holes out to 1/4, and replaced the posts & lower 1x2 spacer. Then, I installed angle braces at the aft intersection of the box and the top of the fuselage jig to be sure that there would be no rotation or lateral movement. I then installed 2 pieces of 1x2 along the aft sides to stiffen the box/jig interface in the vertical direction. Since the jig is slightly tapered, I placed the 1x2s at the point where the edge of the box meets the side of the jig. This left enough room for the attachment bolts through the vertical supports.
15 Sep 2013 (3 hours, total time to date: 890.0 hours)
I aligned the front posts vertically (used my measuring stick to verify the inside distance to BH73.75), drilled the post attachment holes through the sides of the "box," & bolted the posts in place. I removed each upper longeron & formed the bend forward of BH73.75. I replaced the longerons & aimed the bend just inside the front posts, so I'll need to add a little more once I can attach the upper engine mount brackets in place (they are 2 inches aft of the posts). I flattened out the damage to the firewall so I can use it to help position the attachment holes in the front posts. Then, I started work to fit the instrument panel.
16 Sep 2013 (2 hours, total time to date: 892.0 hours)
I was going to brace the sides of the vertical posts with 1x2s, but decided to use the scrap piece of hard plywood that I cut out for the support at BH73.75. The horizontal/vertical C/Ls were already marked (from the earlier application). It will also help to hold the flanges square & provide better support and rigidity. I cut the plywood to fit inside the angles & extent approx. 12 in. below the C/L. I aligned it, clamped it in place, double checked the alignment/spacing of the posts, made some slight adjustments, & drilled 3, 3/16 attachment holes on each side (I used a small piece of 2x4 with a 3/16 hole drilled on my press as a drilling guide). I bolted everything together, checked the plumb one more time, and tightened up the lower attachment bolts.
17 Sep 2013 (1 hour, total time to date: 893.0 hours)
I used a straight 1x2 to find & mark the level line across the vertical posts for the top engine mount holes. It appears that some amount of cutting/trimming will be required to fit the upper engine mount longerons to the 1x1x0.125 longeron & maintain the level line to the engine mount. I called Chris at MA, and will send him some pictures. Since the inward bend of the 1x1 angle results in a downward turn in the 6 inches that the angle extends forward of the instrument panel, something will have to give to allow the engine mount longerons to be spliced in a level line. In addition, something also has to be done to allow the outside face of the angle to sit flush to the flange of BH73.75. I have some ideas, but will wait to discuss with Chris. In the mean time, I decided to add 1x2 braces in front of the posts to provide more stability fore & aft. I extended the fuselage jig 10 inches with 2x4s & attached 1x2s to each side so they can be bolted to the posts just above the plywood shear web. I'm planning to remove the C/L wire when I attach the firewall and want the posts to be very stable. Once I have everything in place and the jig is rigid, I can't see any practical advantage to finding/drilling the C/L hole in the firewall. I will still be able to check the C/L between BH73.75 and the tail cone.
18 Sep 2013 (1 hour, total time to date: 894.0 hours)
I verified that each vertical post was plumb, drilled attachment holes for the braces to the posts, and installed the bolts. Now, the posts are secure in all directions. I talked to Chris about the issue(s) related to the downward bend in the upper 1x1 longerons. Initially, we discussed trimming the forward portion to 0.5 inches to make it easier to bend them back up, and to fit inside the outside flange of BH73.75. He later sent me some pictures of other M1s, that showed that the 1x1 angles can be bent without cutting them down. I'll give it a try on a scrap piece of 1x1 angle first, but this is good info. I just didn't want a twisted mess at the bend. Finally, I fabricated a drilling guide for the 4 attachment holes that connect the instrument panel to BH73.75, removed the longerons, & started work to align the instrument panel.
19 Sep 2013 (1.5 hours, total time to date: 895.5 hours)
I used the drilling guide to drill the instrument panel attachment holes on each side of BH73.75, replaced the instrument panel, checked the alignment, match drilled the holes, & clecoed the panel to BH73.75. Then, I ran a plumb line at the vertical C/L of the jig vertical posts to measure & mark the lateral position of the upper engine mount holes.
20 Sep 2013 (1.5 hours, total time to date: 897.0 hours)
I removed the C/L wire, and was thinking that I could clamp my damaged BH52 (firewall) to the vertical posts & essentially match drill the 3/8 in. holes through them. In order to clear the heads of the bolts, I started cutting pieces of 1x2 until I realized how difficult it would be to get it lined up properly. I decided to scrap that idea and use another piece of 1x1x0.125 scrap angle stock as a drilling guide. I drilled #40 holes spaced at 21 inches (it took a few attempts before I was satisfied with the accuracy). I also used the holes machined in BH52 as an additional check (my experience has been that the eye is good to approx. 0.01 inches - maybe a little better). I then needed to cut and drill some material as spacers (again, to clear the heads of the bolts holding the shear web on the vertical posts). It required a little over 0.125, so I bonded/clecoed two spacers on each end (0.125 & 0.032). Finally, I center-punched and drilled the initial #40 pilot hole at the upper left post location (already marked accurately). I positioned the holes equally spaced from the edge of the angle stock so I can use the opposite leg to set the vertical plumb line.
21 Sep 2013 (5 hours, total time to date: 902.0 hours)
The drilling guide idea didn't work out - it simply wasn't practical since I couldn't think of a good way to check the horizontal distance between the bottom holes (unless I made 2), and it would have been a lot more work to drill out the guide holes as I progressed from #40 to 3/8 in. So, I did what I should have done in the first place, Ran a plumb line down the A/C C/L & measured/marked the bottom holes. It also took some time to get it right, but once done I was more confident that I had the holes placed as accurately as possible. I carefully center-punched the other 3 hole locations and progressively drilled out each hole from #40 to 3/8. I cut ~2 in. lengths of 2x2 to use as spacers between the firewall & the vertical posts (I will adjust the spacers later to set the location/alignment). I mounted my "dented" firewall in place so I could begin work on the forward bend in the upper longerons.
I had been a bit concerned about the process of working the 1x1 angles to take out the downward bend so that the upper engine longerons are level & line up with the upper engine mount bolts. I took some time to practice on another piece of scrap angle and came up with a method that worked for me. The only way I've had success bending the angle was with impact. My bench vise won't cut it, and I don't have a pneumatic/hydraulic press. The way I did it was to turn the angle upside down, clamp it to a piece of plywood on my work table (edge at the location of the desired bend point), used my hard wood bending tool (see 5 Sep 2013), & struck the tool with my hand sledge. I re-positioned the angle to work the bend as needed. Believe me, it took a lot of hits - this stuff is tough. Also, as the downward bend is removed, the inward bend is removed to some extent. Therefore, the process is slow, and I needed to make several iterations with the process in both directions. In the end, I think it turned out well - what a relief.
Finally, I needed to round the edges of the angles that nest inside the upper engine mount longeron channels. I did the initial rounding on my belt sander, then hand sanded, and used my scotch brite wheel to polish/smooth the edges. I placed the pieces in place to take the picture shown here. Not bad......
I had been a bit concerned about the process of working the 1x1 angles to take out the downward bend so that the upper engine longerons are level & line up with the upper engine mount bolts. I took some time to practice on another piece of scrap angle and came up with a method that worked for me. The only way I've had success bending the angle was with impact. My bench vise won't cut it, and I don't have a pneumatic/hydraulic press. The way I did it was to turn the angle upside down, clamp it to a piece of plywood on my work table (edge at the location of the desired bend point), used my hard wood bending tool (see 5 Sep 2013), & struck the tool with my hand sledge. I re-positioned the angle to work the bend as needed. Believe me, it took a lot of hits - this stuff is tough. Also, as the downward bend is removed, the inward bend is removed to some extent. Therefore, the process is slow, and I needed to make several iterations with the process in both directions. In the end, I think it turned out well - what a relief.
Finally, I needed to round the edges of the angles that nest inside the upper engine mount longeron channels. I did the initial rounding on my belt sander, then hand sanded, and used my scotch brite wheel to polish/smooth the edges. I placed the pieces in place to take the picture shown here. Not bad......
22 Sep 2013 (3 hours, total time to date: 905.0 hours)
Removed the longerons & instrument panel. Finished the edges of the instrument panel to remove all of the tool marks. When I took Troy Grover's RV builders class, he called it "character building". I then started work trimming the flange & web of BH73.75 to allow the upper longeron angles to lay flush with the flange to form a continuous edge for the fuselage skin. This took a few iterations because the instrument panel attachment holes are close, and I wanted a nice fit. Once the fit was close, I clamped the longerons back in place and made more adjustments to the forward bend in each 1x1 angle (both directions) so that the upper engine mount longerons would line up properly with the engine mount bolts. This took several iterations before I was satisfied. There may be a little more "tweaking" once I get the longerons clecoed in place. I will also need to fabricate a brackets to hold the longerons at BH73.75. In the meantime, 2 pieces of scrap material are clamped to the flanges to hold the longerons flush.
23 Sep 2013 (1 hour, total time to date: 906.0 hours)
Drilled the engine mount hole in the mounting brackets out to 3/8 in. & de-burred the holes. Starting laying out the location of the mounting holes in the firewall attach plates.
24 Sep 2013 (1 hour, total time to date: 907.0 hours)
Still waiting for the new firewall, so I turned my attention to the instrument panel. The vertical webs/flanges of BH73.75 were curved slightly forward, so I went back over the flutes to straighten them out. There is very little room between the header tank and the instrument panel, so I want to get all of the space possible. I replaced the instrument panel & ran a plumb line to mark the C/L on the panel. I began work marking the panel so that I can add removable sections for easier maintenance/replacement of instruments/avionics. I want to extend the panel approx. 3-3.5 inches to allow for more flexibility in terms of avionics. Finally, I marked the edges of the panel around the recent longeron trim lines, removed the panel, trimmed it to match, & replaced it.
25 Sep 2013 (1 hour, total time to date: 908.0 hours)
After placing instrument templates on the panel, I decided to change the panel layout. I want to have some type of "glass" on the panel - primarily for a moving map & ADS-B. Using it for a PFD is also attractive, but I'm not comfortable putting all of my instruments in a single device that can fail. Technology changes quickly, so it seems wise to do as much as possible to keep my options open. Dividing the panel into 3 sections will allow me to make changes and maintenance will also be much easier. Standard, full-size radios will never fit behind the fuel tank, and I believe I can install a 6.5 in. stack in front of the control stick. This will also give me a lot of options. My layout will allow for 3, 2.25 in. steam gauges on the left & right sides, and the center section will allow room for anything up to 7Wx8Hx5D. I'll also have room below for switches & 1.25 in. gauges. The distance below the extended panel is now 12.375 in. This will make things a little tighter, but should work. The tank is lower anyway and is less than 6 in. away. I've seen other M1 examples of panels that are extended to what looks like the same/similar position.
So, for the actual work done..... I made the changes to the panel layout & installed a 1x1x0.0625 angle in position to attach the bottom of the extended panel. It will also serve as the upper attach point for the radio stack. I'll trim the upper leg of this angle after drilling the pilot attachment holes for the extended lower panel flange.
So, for the actual work done..... I made the changes to the panel layout & installed a 1x1x0.0625 angle in position to attach the bottom of the extended panel. It will also serve as the upper attach point for the radio stack. I'll trim the upper leg of this angle after drilling the pilot attachment holes for the extended lower panel flange.
26 Sep 2013 (1 hour, total time to date: 909.0 hours)
Marked, drilled & de-burred #41 pilot holes along the aft end of each longeron (tail cone area) using the recommended 1.5 in. spacing. Also marked the tapered trim lines for the other leg in that area.
27 Sep 2013 (1.5 hours, total time to date: 910.5 hours)
Cut the aft section of each longeron along tapered trim line. I started the taper after the second rivet since the rivets can only carry ~350# (ultimate), so there is no need for the additional material until the load builds up and can redistribute to the other leg. I used my belt sander to clean up/smooth the edges & finished with the scotch brite wheel. I also spent some time softening the corners of the longerons where they interface with the skin. I may do a little more later, but this was a good time to work on them. Then, I took another look at the interface between the longerons and BH73.75. I need to come up with a good way to secure the longerons here so that I can use a cargo strap to pull the skin around the BHs. The problem is finding a location that will not interfere with future connections to the skin. It looks like I will need to drill a couple of skin attach holes at the top of the flange at BH75.75 and temporarily attach some scrap 0.032 to hold the longerons flush/level. I cut 2 sections of 1x1x0.062 angle to use as clips to secure the longerons in front of the BH through 2 of the existing holes for the IP. The inside angles are awkward, so I will have to give this more thought.
28 Sep 2013 (1 hour, total time to date: 911.5 hours)
Drilled out (progressively) the holes in the firewall attach plates to 3/8 in. Removed each spacer & used my disk sander to adjust the length to get the proper distance between BH52 (Firewall) & BH73.75.
29 Sep 2013 (1.5 hours, total time to date: 913.0 hours)
Mounted the upper firewall attach plates & engine mount brackets to check the fit of the upper fuselage stringers. The forward bend in the upper longerons required a little more "tweaking" to improve the fit. I rechecked the level of the longerons & temporarily clamped them in place.
The fit is good, but before going further I need to consider how I'm going to attach the skins along the bottom flange of BH73.75. There is simply no room to buck rivets between the flange and the lower spar carry-through beam. I can use nut plates, but will have to remove the BH to install them. I really don't want to use blind rivets unless there is absolutely no choice. The other issue is to be sure to carry the load across the splice. Based on some back of the envelope numbers, I'd feel very safe (ultra-conservative) if the splice was capable of carrying ~5300 lbs (ultimate) across the lower portion of the skin splice. That's about what I estimate the upper longerons would carry at +9 g's & 1000# GW). The lower load from the engine mounts is carried through the stringers into the skin, so the most direct path is there. I also prefer to keep the 3G gross section stresses below 8 ksi whenever possible. So, I've got some more thinking to do......
The fit is good, but before going further I need to consider how I'm going to attach the skins along the bottom flange of BH73.75. There is simply no room to buck rivets between the flange and the lower spar carry-through beam. I can use nut plates, but will have to remove the BH to install them. I really don't want to use blind rivets unless there is absolutely no choice. The other issue is to be sure to carry the load across the splice. Based on some back of the envelope numbers, I'd feel very safe (ultra-conservative) if the splice was capable of carrying ~5300 lbs (ultimate) across the lower portion of the skin splice. That's about what I estimate the upper longerons would carry at +9 g's & 1000# GW). The lower load from the engine mounts is carried through the stringers into the skin, so the most direct path is there. I also prefer to keep the 3G gross section stresses below 8 ksi whenever possible. So, I've got some more thinking to do......
30 Sep 2013 (2 hours, total time to date: 915.0 hours)
Removed the stringers, longerons, & BH73.75 from the fuselage jig. Laid out & drilled #41 pilot holes along the bottom of the BH flange. I centered the holes between each flute to leave plenty of room to install nut plates (if I decide to go that way when the time comes). I cut out a piece of 0.032 sheet to approx. 5x13 in. to attach to the flange and allow additional (accessible) material on each side of the BH for lower skin attachment. I used a strap duplicator to locate the holes. I ended up fabricating a second piece because one of the holes was not lined up (the curvature made things a little more difficult). Since it was not easy with the BH removed, I decided to make a drilling guide strip by match drilling the holes. I believe that I'll need to make another one to use over the tunnel since the additional thickness will amplify the curvature issue. Better to do all of this now than try to do it on my back in a very limited space. I don't know how anyone could do it with the BH in the jig - especially if built to the height in the plans. I've got my airplane up 4 more inches, and it's very cozy.
1 Oct 2013 (1 hour, total time to date: 916.0 hours)
Cut & shaped a 1x4 to match the curvature of the bottom flange of BH73.75. I may need to use it to fabricate "memory sticks" to help me drill through the bottom skins. I marked & drilled the skin attach pilot holes in the BH flange between the upper and lower spar attachment holes. Finally, I used a router to remove some plywood between the spar attach holes to provide clearance for clecos.
2 Oct 2013 (1 hour, total time to date: 917.0 hours)
Laid out & drilled the skin attach holes along the side flanges of BH73.75.
3 Oct 2013 (1 hour, total time to date: 918.0 hours)
Cut a piece of 1x2 to fit under the upper spacers for the firewall & clamped it to the firewall attach plates. This holds the firewall flat so I can verify the distance to the upper BH73.75 web. I want to be sure that I position the longerons correctly at the BH. I fabricated 2 0.032 straps (~3x0.75) to temporarily attach to the upper 2 skin attach holes on the flanges of BH73.75 & hold the longerons flush to the outside of the flanges. Well, they were simply not sufficient to hold the longeron at the proper angle, so I cut two pieces of 1x1x0.062 angle stock to do the job. I transferred the holes from the straps & clecoed them to the flanges. Now, the longerons can be clamped flush to the skin line, and I can get things in the proper position (level in both directions).
4 Oct 2013 (2 hours, total time to date: 920.0 hours)
Checked, adjusted, re-checked the longeron alignment (a few times - ;-) ). It was almost a juggling act. Besides the leveling in both directions, I also needed to be sure that the sides of BH73.75 remained in-plane (21.75 in. from the firewall). In the end, I managed to get a 0.0 reading on my digital level in each direction (side to side, fore, aft and in-between). Nothing is ever perfect, but this is as perfect as I could ever hope). Now, will it stay that way as I skin it? Who knows? However, I'm happy for now.
I'm sure there are many ways to hold the longerons in place at BH73.75, but here's how I decided to do it: I peeled the plastic away from the IP in the area that will be sandwiched between the "clip" I've decided to use to hold the longeron and the BH web. This was more than likely overkill, but it made me feel better. I trimmed and finished the 0.062 in. thick angle clip to fit nicely inside the longeron. The compound angles made this necessary. I used the upper 2 attach holes to make things easier, and I think 2 are plenty anyway. I clamped the to the inside of the longeron and made sure it was in tight contact with the BH web & used a long #41 drill bit to reach inside from the rear. Once I had the 2 web attach holes drilled out and clecoed, I re-checked the web distance from the firewall & drilled a single attachment hole through the top of the longeron. This holds the longeron at the proper angle as well as keeping the BH web in place. I accomplished this work for the left side today and will take care of the right side tomorrow.
I'm sure there are many ways to hold the longerons in place at BH73.75, but here's how I decided to do it: I peeled the plastic away from the IP in the area that will be sandwiched between the "clip" I've decided to use to hold the longeron and the BH web. This was more than likely overkill, but it made me feel better. I trimmed and finished the 0.062 in. thick angle clip to fit nicely inside the longeron. The compound angles made this necessary. I used the upper 2 attach holes to make things easier, and I think 2 are plenty anyway. I clamped the to the inside of the longeron and made sure it was in tight contact with the BH web & used a long #41 drill bit to reach inside from the rear. Once I had the 2 web attach holes drilled out and clecoed, I re-checked the web distance from the firewall & drilled a single attachment hole through the top of the longeron. This holds the longeron at the proper angle as well as keeping the BH web in place. I accomplished this work for the left side today and will take care of the right side tomorrow.
5 Oct 2013 (3 hours, total time to date: 923.0 hours)
Checked the alignment of the right longeron and IP once again, and installed the right clip in the same manner as was done for the left side. Once this was clecoed in place, I made sure the longerons were still in proper alignment (they are). I then started drilling out the longeron attachment holes along each side of the tail cone. The #41 pilot holes provide a nice tight fit for the clecos - I know I will be removing pieces fairly often. I worked my way aft from BH99.35 & removed the clamps that were holding the longerons in place. Looking good.....
I cut a strip of 0.032 sheet (approx. 1.7 in. wide) to attach to the top of the IP. This will serve as the canopy seal (I will trim it later as required). The flange tabs on the IP are not symmetric, so I'm going to see what I can do to position the upper skin nut plates as evenly as possible. Finally, I cut out a 0.040 blank that will be the lower portion of my extended IP. I will need to "borrow" a bending brake to form the lower flange and the small angle to line up with the canted IP provided by MA. I will attach the lower flange to the 0.062 angle I installed earlier.
I cut a strip of 0.032 sheet (approx. 1.7 in. wide) to attach to the top of the IP. This will serve as the canopy seal (I will trim it later as required). The flange tabs on the IP are not symmetric, so I'm going to see what I can do to position the upper skin nut plates as evenly as possible. Finally, I cut out a 0.040 blank that will be the lower portion of my extended IP. I will need to "borrow" a bending brake to form the lower flange and the small angle to line up with the canted IP provided by MA. I will attach the lower flange to the 0.062 angle I installed earlier.
6 Oct 2013 (3 hours, total time to date: 926.0 hours)
I laid out the bend lines on the 0.040 thick sheet I cut to become the lower portion of my extended IP. The folks at Stewarts Aircraft Service (I73) allowed me to use their bending brake, so I drove over and made the bends in the sheet. It took a little time to fit the part. I needed to adjust the bends slightly so that the canted angle of the original IP would line up with the upper attachment lip of the new part. When I got it where I wanted it, I clamped it in place & started work attaching the canopy seal to the IP flange.
7 Oct 2013 (2 hours, total time to date: 928.0 hours)
Removed the IP and began laying out fastener locations for the 3 upper sub-panels. Since I will need to cut out sections of the original panel, I want to be sure to provide proper support - especially along the sides (around the v-notches). I designed doublers to support the sides (front and back). I drew and cut-out paper patterns, transferred the patterns to a piece of 0.040, cut, and finished all 4 pieces. I also cut & finished the edges of the center panel (I left it slightly long for now). I want to have the fastener holes drilled before making any cuts in the original IP.
8 Oct 2013 (1.5 hours, total time to date: 929.5 hours)
Formed a joggle in the "front" doublers where the double will wrap around the front of the IP & made the bend in the rear doublers at the bend line in the IP. Drilled the #41 pilot attach holes for the rear doublers & clecoed them in place.
9 Oct 2013 (1.5 hours, total time to date: 931.0 hours)
Replaced the IP on BH73.75 & checked the fit of the front doublers. I trimmed & finished the doublers as necessary to make a nice, clean fit, measured, marked, & drilled the attachment holes through the left BH web. Once the left doubler was clecoed in place, I drilled the pilot attachment holes through the existing lower holes in the left rear doubler. Finally, I trimmed/finished the right front doubler & started drilling the attachment holes.
10 Oct 2013 (1.5 hours, total time to date: 932.5 hours)
Drilled the remaining pilot attachment holes for the right, front IP doubler. Removed the IP, & made a few minor changes to the fastener layout for the 3 removable sub-panels. Drilled the pilot holes in the IP along the outside (adjacent to the canopy seal). Positioned the center sub-panel & match drilled the pilot holes along the top edge. Finally, I measured & rough cut the left sub-panel.
11 Oct 2013 (1 hour, total time to date: 933.5 hours)
Finished the upper/adjoining edges of the left sub-panel. Cut & finished the right sub-panel in the same manner. Taped the panels in place & drilled out the pilot attachment holes around the perimeter of the IP.
12 Oct 2013 (1 hour, total time to date: 934.5 hours)
Replaced the IP on BH73.75, checked the fit of the left & right sub-panels, and trimmed the edges as necessary. Finished the sides & laid out the fastener hole locations down the sides of the center panel.
13 Oct 2013 (1 hour, total time to date: 935.5 hours)
Drilled pilot attachment holes to connect the new lower panel to the horizontal leg of the 0.062 angle that spans the web of BH73.75. I left space on each side at approx. 3 from the C/L - I will drill that area later when I'm ready to install the radio stack. I then drilled the upper 3 pilot holes along the sides of the center panel, replaced the panel, & match drilled the upper 2 holes through the IP. I repeated this for the sides of the left & right panels. The lower holes are below the bend in the IP, so I will have to wait until I have made the cuts in the IP and have straightened the "strips" between the panels. I laid out the cut lines in the IP around the perimeter and the strips between the sub-panels. The next step is to replace the panel to locate the cut line for the bottom of the sub-panels & lay out the fastener locations to attach the sub-panels to the lower panel.
14 Oct 2013 (2.5 hours, total time to date: 938.0 hours)
Removed the left & right sub-panels, replaced the IP, and marked the location of the upper flange of the lower panel. Removed the center panel, cut, trimmed, & finished the bottom edge. Measured & drilled the pilot attachment holes along the bottom of the center panel. I used a spacing of approx. 2 inches allowing for the attachment strips on each side. Replaced the center panel, lightly clamped the bottom edges to the lower flange, & match drilled the pilot attachment holes through the flange. I then started working on the left & right sub panels. I trimmed/finished the front doublers to provide clearance behind the left & right panels. I then repeated the process used for the center panel to drill the attachment pilot holes through the lower flange. Finally, I removed the sub-panels & IP to cut holes in the IP along the upper end of the sub-panel attachment strips. These holes will form the transition from the upper edge of the IP.
15 Oct 2013 (1 hour, total time to date: 939.0 hours)
Cut the lower portion of the sub-panel attach strips just above the 6 degree bend line. Removed the bends in the strips - used one of my bucking bars as an anvil to finish the flattening process. Mounted the IP to BH73.75 to mark the intersection of the strips at the top of the lower panel flange. Removed the IP to cut the strips to the intersection. Drilled the lower holes on the sides of the sub-panels, then replaced each panel, & match drilled the holes through the IP attachment strips. I'm holding off on finishing the IP cut-outs until I have finished fitting angle stiffeners to the back of the attachment strips. The stiffeners will also serve to attach the strips to the lower panel flange.
16 Oct 2013 (2 hours, total time to date: 941.0 hours)
Cut 4 pieces of 0.032 angle stock to span the height of the IP attachment strips (including enough to make the attachment to the lower flange). I had previously bent some 32 inch lengths of 0.032 thick 2024 at a local machine shop to use as stiffeners as needed. The procedure I used for each side was to cut & finish one leg of each angle to 9/16 (IP attachment side). The outstanding legs were previously cut to approx. 0.65 in. I clamped each pair of angles together & cut/finished the top edge to fit neatly at the upper flange of the IP. I marked the fastener line on the IP side of each angle & clamped/duct taped the angles in place on the back of the IP - aligned with the fastener line along the sub-panel attachment strips. I match drilled the attachment holes through the angles and installed clecos. Then, I clamped the outstanding legs of each pair together, removed the clecos, & cut/finished a taper along the top of the outstanding legs. This was done to provide clearance for the nut plates that will be installed for the canopy seal/upper fuselage skin. The outstanding legs provide no structural advantage at the top edge, so the taper is also more structurally efficient. I still need to drill attachment holes in the outstanding legs for additional stability & will install 2 nut plates along the lower portion of each side to allow for the use of Adel clamps for instrument wiring/tubing.
17 Oct 2013 (1 hour, total time to date: 942.0 hours)
Removed the outside panel stiffeners on each side, measured, marked, & drilled (MMD) #41 holes in the outstanding flanges between the IP attachment holes in the other leg. These holes will be used to secure the angles and nut plates will be installed in 2 locations on each side for Adel clamps. Replaced the stiffeners on the IP & match drilled the new holes through the companion stiffeners. Replaced the IP on BH73.75 to locate the edge of the lower panel flange bend line on the IP stiffeners. Removed the stiffeners to MMD the pilot attachment holes to the lower panel flange. Replaced the stiffeners on the IP.
18 Oct 2013 (1 hour, total time to date: 943.0 hours)
Drilled the lower stiffener attachment pilot holes through the lower panel. Removed the stiffeners and started work to install 3 nut plates on the outstanding legs of each set of stiffeners. I drilled out the desired nut plate holes to #30 (I'd rather drill out the holes progressively & I can use my #30 clecos to hold the stiffeners together). To fit the 8-32 nut plates, I drilled each hole to #19, cut out & drilled a #19 hole in 1/8 plywood to make a spacer, attached a nut plate using a #8 machine screw (with the spacer on the opposite side), match drilled the first #40 attachment hole through the nut plate, inserted a -3 rivet in the hole to prevent rotation, & drilled the second #40 attachment hole. I finished the process for the 3 nut plates on the left stiffener.
19 Oct 2013 (3 hours, total time to date: 946.0 hours)
Disassembled the left stiffener angles, de-burred/finished, acid etched/alodined, & applied a light coat of primer on the mating surfaces of the angles. While the primer was curing, I drilled the nut plate attachment holes in the right IP stiffener & repeated the process used for the left stiffener angles. I then installed the nut plates and 2, -3 universal head rivets on the outstanding legs of the stiffeners and replaced them on the IP.
20 Oct 2013 (2 hours, total time to date: 948.0 hours)
Removed the IP, replaced the sub-panels, & drilled the sub-panel attachment holes out to #30. Since I will be using #6 C/S machine screws, I will be drilling them all out to #28 prior to dimpling, but I discovered that I need to order 6-32 nut plates for the dimpled holes. I will wait until I have them in hand before drilling the holes to the final size. I removed the right longeron and MMD #40 skin attachment pilot holes between BH99.35 & 73.75 (1 in. spacing).
21 Oct 2013 (1 hour, total time to date: 949.0 hours)
Removed the left longeron & MMD the skin attachment holes. Also, cut out two small pieces of 0.040 sheet to use as spacers between the longeron clips and BH73.75. I need to use to take up the space of the IP because I will not be able to install the rivet on the top of the longeron with the IP in place. There is no way to get a rivet gun or squeezer in that space unless the IP is off.
22 Oct 2013 (1 hour, total time to date: 950.0 hours)
Removed the longerons & match drilled the upper IP attachment holes through the spacers I cut out yesterday. Trimmed the spacers to fit under the longeron. Attached the spacers and longeron clips to BH73.75. Replaced the longerons & clecoed the forward ends to the attachment clips. Clamped the longerons to the clips, removed the clecos, & drilled the holes out to #30. Removed the longerons/clips, de-burred the holes, etched, and alodined the clips and forward end of the longerons in preparation for riveting the clips to the longerons.
23 Oct 2013 (1.5 hour, total time to date: 951.5 hours)
Replaced the longerons & clecoed the clips in place. I used cleco clamps to hold the longerons to the clips, removed the top clecos, inserted the -4 universal head rivets through the top of the longerons, & used my pneumatic rivet squeezer (with a longeron yoke) to set the rivets. I can still remove the longerons as needed by removing the clecos holding the clips to BH73.75.
Resumed work on the bottom skin doubler at BH73.75. I fabricated 2 additional drilling templates & stacked them to match drill the attachment holes on a 1x4 that I had shaped to match the curvature of the bottom skin flange. I may be able to use them to locate the attachment holes through the overlapping skins.
Resumed work on the bottom skin doubler at BH73.75. I fabricated 2 additional drilling templates & stacked them to match drill the attachment holes on a 1x4 that I had shaped to match the curvature of the bottom skin flange. I may be able to use them to locate the attachment holes through the overlapping skins.
24 Oct 2013 (0.5 hour, total time to date: 952.0 hours)
I didn't have a lot of time today, but managed to MMD a second row of fastener pilot holes in the bottom skin doubler, aft of the lower flange of BH73.75. These will be accessible for riveting, and I feel a bit better about having some redundancy as well as more stability/load carrying capability. I plan to install nut plates inside the flange, but the fastener spacing here is approx. 1.75-2 inches due to the location of the flutes. I will have to use blind rivets (probably Cherry Max) in the 2 outboard holes - simply no clearance to install nut plates. I also did a little trimming/finishing of the doubler. I used a spacing of 1-3/8 along the second row. It worked out evenly and offsets the fastener pattern.
A couple of notes I wanted to add: I received the "countersunk" 6-32 nut plates from Wicks that I intended to use for he IP. It was good that I waited to drill out the holes since the only holes dimpled on the nut plates were the attachment holes - not what I had in mind. However, it's probably just as well. It will take some time, but I can cut some 0.062 thick strips to install behind the IP. I can C/S the fastener holes in the strips & the dimples will nest in them. That will also provided more stability for the IP without much added weight. When I consider the weight of a "glass panel" over three, 3-1/8 steam gauges, I'm probably still coming out better. I'll also need to make new rear doublers out of 0.062 sheet. Also, I'm happy to have received the new firewall, engine mount, & fiberglass seat back from MA.
A couple of notes I wanted to add: I received the "countersunk" 6-32 nut plates from Wicks that I intended to use for he IP. It was good that I waited to drill out the holes since the only holes dimpled on the nut plates were the attachment holes - not what I had in mind. However, it's probably just as well. It will take some time, but I can cut some 0.062 thick strips to install behind the IP. I can C/S the fastener holes in the strips & the dimples will nest in them. That will also provided more stability for the IP without much added weight. When I consider the weight of a "glass panel" over three, 3-1/8 steam gauges, I'm probably still coming out better. I'll also need to make new rear doublers out of 0.062 sheet. Also, I'm happy to have received the new firewall, engine mount, & fiberglass seat back from MA.
25 Oct 2013 (1 hour, total time to date: 953.0 hours)
I tapered/finished the edges of the aft end of the bottom doubler and started work cutting lower side doublers to fit around the wing attach area of BH73.75 & extend upward along the flange. I'm not sure exactly how they will fit when all is said & done, so I'm cutting out larger blanks than I think I will need. My plan is to use the side doublers to hold the aft end of the lower stringers in position, provide additional support around the wing attachment/skin splice, and allow more area for the load to transition into the skin. Down the road, I will need to consider the location of the nut plates for the wing fairings and cut-outs for the brake & wing fuel lines.
26 Oct 2013 (3 hours, total time to date: 956.0 hours)
I was a little surprised that it took me 3 hours, but it sure did. I removed the dented firewall & replaced it with the new firewall from MA. I also mounted the lower engine mount brackets so that I could get a better idea where the lower stringers will end up at BH73.75. I then needed to remove BH73.75 to measure/test fit the location of the cut out in the side doublers (around the upper wing attach clevis). I marked the location of the cut-out, drilled holes in the corners, & made the rough cuts with my Dremel. I rounded the corners with a 1/4 in. drum. It took a couple of iterations to get the fit I wanted. I finished the edges of the cut-out & finished the bottom & back edges (I don't expect to trim those sides). Repeated the process on the other doubler. Finally, I slipped the doublers over the upper wing attach clevis(es) & replaced the BH on the fuselage jig.
27 Oct 2013 (3 hours, total time to date: 959.0 hours)
Another 3 hours to fit the side doublers to BH73.75.
Aligned the side doublers along the BH73.75 skin attach flanges. Drilled the upper attachment pilot hole using my strap duplicator and back-drilled the rest using a 12 in. #41 bit. I decided to drill the lower 2 holes on each side (between the wing attach fittings) after removing the BH from the jig. Measured & marked trimming lines to adjust the side doublers a little bit more (I'll probably do more after fitting the lower stringers to it). Removed the BH (again), trimmed/finished the edges of the side doublers. Replaced the doublers, and used the strap duplicator to drill the lower pilot holes. Replaced the assembly back on the jig to take a good look things before going forward.
Aligned the side doublers along the BH73.75 skin attach flanges. Drilled the upper attachment pilot hole using my strap duplicator and back-drilled the rest using a 12 in. #41 bit. I decided to drill the lower 2 holes on each side (between the wing attach fittings) after removing the BH from the jig. Measured & marked trimming lines to adjust the side doublers a little bit more (I'll probably do more after fitting the lower stringers to it). Removed the BH (again), trimmed/finished the edges of the side doublers. Replaced the doublers, and used the strap duplicator to drill the lower pilot holes. Replaced the assembly back on the jig to take a good look things before going forward.
28 Oct 2013 (1.5 hours, total time to date: 960.5 hours)
I determined the amount of space required for my rivet gun to set rivets adjacent to the vertical BH support. Removed BH73.75 from the fuselage jig, removed the side doublers, and laid out the forward/mid fuselage skin attachment holes. Drilled the #41 pilot holes in each doubler. I did not drill any pilot holes in the "toe of the boots," or within 2.5 inches of the bottom of the doublers (ahead of the BH flange) because I may need to trim them again once I fit the lower stringers.
29 Oct 2013 (2.5 hours, total time to date: 963.0 hours)
I replaced the side doublers on BH73.75 & installed NAS1097-3 reduced head rivets at 4 selected locations (top, bottom, & two intermediate locations) to hold the doublers securely to the BH in preparation to fit the fuselage skins. I then replaced the bottom doubler and installed 2 1097 rivets to hold it in place. It turns out that I was mistaken about being able to install nut plates in all of the holes except the two outside holes. I won't be able to install nut plates in 4 outside holes due to limited space. Therefore, I installed the 1097's in the third hole from the outside edge on each side of the bottom flange. I then replaced the assembly on the fuselage jig & replaced the longerons. Finally, I spent some time investigating the procedure I will use to C/S the #6 machine screw holes around the periphery of the IP. I tried several combinations of dimples (0.032) and C/S (0.062). I found that it is not possible to properly nest a #6 dimpled hole inside a C/S in a 0.062 plate without over-sizing the hole and/or creating a knife edge condition. I have decided that the most practical solution is to dimple the holes using a -4 dimpler, and C/S the backing plate with a #27 C/S. The #6 machine screw will be slightly proud, but is a much better option IMO. I won't be able to do this for the holes under the sub-panels, so I will have to use the more expensive k1100-6 nut plates that has the provision for a dimpled hole.
30 Oct 2013 (1 hour, total time to date: 964.0 hours)
Cut out new 0.062 thick rear doublers for the IP that extend around the periphery and allow me to C/S the nut plate holes and provide more stability for the panel. I did a little light finishing work, but will be trimming the inside edges again once I have the attachment holes finished.
31 Oct 2013 (1.5 hours, total time to date: 965.5 hours)
Cut and did light finishing work on the 0.062 doubler that fits on the back of the IP between the stiffeners along the top edge. Match drilled the #30 attachment holes for the upper rear doubler. I then marked & used my forming blocks to make the slight bend in the new rear side doublers. Finally, I clamped the side doublers in place, match drilled the attachment holes, & clecoed the assembly together. As mentioned earlier, I will need to trim the inside edges a little more, but I left plenty of room.
1 Nov 2013 (2 hours, total time to date: 967.5 hours)
Match drilled the lower #40 pilot attach holes through the bottom of the side doublers. I fabricated duplicate left/right sub-panels and am nearly finished duplicating the center panel. I want to have them available in case changes are required to the IP configuration down the road, and it's much easier to make the duplicates before the attachment holes are dimpled.
2 Nov 2013 (4 hours, total time to date: 971.5 hours)
Finished duplicating the center panel. Marked and made the final trim cuts on the inside of the side doublers. Finished the edges of the 0.062 doublers & clecoed them back in place. Drilled the nut plate attachment holes for the standard #6 nut plates around the circumference of the IP (also drilled a #40 rivet hole on the lower portion of each side doubler). Removed the doublers and stiffeners, removed the plastic from the IP, and de-burred all of the holes. Dimpled (#30) the panel attachment holes in the stiffeners, and used my C-frame to dimple the corresponding holes on the right side of the IP. Clecoed the right stiffener to the IP, & used C/S #6 machine screws to secure two of those expensive K1100-6 nut plates in the upper holes. I'll resume work tomorrow drilling out the nut plate attach holes.
3 Nov 2013 (5 hours, total time to date: 976.5 hours)
I'm sure spending a lot more time on my IP redesign than originally expected, but I'm just about ready to put it all together. I finished drilling the nut plate attachment holes along the right & left panel stiffeners. C/S the machine screw holes in the IP doublers & dimpled the holes in the IP & sub-panels. I also realized that I needed to dimple the lower attachment holes (below the bend in the original IP), & C/S the corresponding holes in the side doublers. These holes attach the IP to BH73.75 though a 0.032 splice between the new lower panel, so I had to replace the IP assembly on the BH & match drill #30 holes through all of the parts. Finally, I taped the edges of the original IP, marked the cut lines, & made the rough cuts with my Dremel.
4 Nov 2013 (2 hours, total time to date: 978.5 hours)
Finished the rough cut edges in the IP using a sanding disk on my pneumatic die grinder & sanding drum on my dremel tool. Continued finishing the edges with hand sanding & scotch brite pads. I then de-greased, acid etched, & alodined the IP & doublers in preparation for assembly (the stiffeners have already been alodined). Looking pretty good.
5 Nov 2013 (1.5 hours, total time to date: 980.0 hours)
Applied a light coat of primer to the mating surfaces of the doublers, stiffeners, & IP. After the primer had cured, I stared work attaching the nut plates around the circumference of the IP. The doublers/stiffeners are sandwiched between the IP & the nut plates.
6 Nov 2013 (1 hour, total time to date: 981.0 hours)
Finished installing rivets/nut plates around the circumference of the IP. Started installing the nut plates along the stiffeners.
7 Nov 2013 (2 hours, total time to date: 983.0 hours)
Finished installing the nut plates along the stiffeners, & replaced the sub-panels. I printed/laminated a full scale image of a Garmin GDU370 that will fit very nicely in the center panel. This re-design took quite a bit of time, but I'm glad I did it. Who knows what else may be available in a year or two, but the extra space will provide more options and much easier maintenance.
I found a product called "RAM BOARD" that I hope will help me fit the forward fuselage skin. The product is intended for use as a floor protector, but I plan to use it to make a skin template to locate the skin cut-outs. I marked the C/L along the bottom of BH73.75 & 99.35 & started laying out the RAM BOARD around the bottom of BH73.75.
I found a product called "RAM BOARD" that I hope will help me fit the forward fuselage skin. The product is intended for use as a floor protector, but I plan to use it to make a skin template to locate the skin cut-outs. I marked the C/L along the bottom of BH73.75 & 99.35 & started laying out the RAM BOARD around the bottom of BH73.75.
8 Nov 2013 (1 hour, total time to date: 984.0 hours)
Finished marking & cutting templates for the cut-outs for the wing attach fittings at BH73.75 & the rear spar cut-outs at BH99.35. Also, measured reference distances needed to fabricate a "practice" skin out of the RAM BOARD material. Before I cut any metal, I want to double check the fit and see if there will be any problems fitting the real skin. My biggest concern is how to fit the skin around the attach fittings while BH73.75 is in place (especially after I form the lower curvature in the skin).
9 Nov 2013 (1 hour, total time to date: 985.0 hours)
I cut 73 inches of the 36 inch wide RAM BOARD to wrap around the fuselage & transferred the cut-out patterns from the templates I made for BH73.75 & 99.35. I cut the new, full-size template slightly larger (always easier to cut more off). I estimated the angle required at BH99.35 to overlap the BH flange. As I attempted to place the template in position, it became very clear that I will need to remove BH73.75 (or at least, remove the longerons) to allow me to lay the skin in place. Once in place, I used duct tape to hold it in place - my estimate of the cut angle at BH99.35 was not sufficient. I cut two strips of material to cover the gap. Finally, I marked the inside of the template to allow me to make final measurements for the template once I remove it.
It would clearly be much easier to assemble the mid-fuselage skin if I cut it into 3 pieces, & install the bottom portion first. I know this has been been commonly done, but I will have to do more research to decide where I would make these cuts/splices. Right now, I am leaning toward this approach. If I use the 3-piece approach, I will be able to do a lot more of the riveting work myself. I may also be able to take advantage of the splice as an additional stiffener to attach arm rests/throttle quadrant/flap actuator.
It would clearly be much easier to assemble the mid-fuselage skin if I cut it into 3 pieces, & install the bottom portion first. I know this has been been commonly done, but I will have to do more research to decide where I would make these cuts/splices. Right now, I am leaning toward this approach. If I use the 3-piece approach, I will be able to do a lot more of the riveting work myself. I may also be able to take advantage of the splice as an additional stiffener to attach arm rests/throttle quadrant/flap actuator.
10 Nov 2013 (1 hour, total time to date: 986.0 hours)
Double checked the template fit, made a few adjustments, & drew a horizontal line on the inside of the template along the top of the upper wing attach lug between BH73.75 & 99.35. This appears to be a good location for the skin splice, but I still want to check to be sure this will not interfere with any other fittings that will need to be installed later (i.e. flap control quadrant). I removed the template & cut it to final size.
11 Nov 2013 ( 2 hours, total time to date: 988.0 hours)
Traced the lower, center skin template on another piece of RAM BOARD, cut it out, & did another trial fit. It is going to be difficult to fit the real skin around the wing attach cut-outs (removing the BH doesn't work). I will take a look at cutting a corners above the lower lug to see if I can get clearance to rotate the skin in place from the aft end. I also used cargo straps to hold the new template tightly to the BHs, re-checked fit, and made a few more adjustments. Although I haven't made the final decision on where (if) I'm going to splice the center skin, I cut out 2 pieces of 0.040 sheet to fabricate stringers for the splice. I bent a 0.75 in. flange in one of the blanks. I can always trim it later, and may be able to use the extra room to connect internal fittings. I bought an inexpensive bench top bending brake at Harbor Freight, and it did the trick. However, for what it's worth, it's advertized to bend up to 16 guage Al. Also, the first thing I did to the tool was to round the edge of one side of the steel bending block & used a piece of previously bent 0.032 angle to provide a nice bend radius for the 0.040 material. I can safely say that 27.5 in. wide, 0.040 thick A/C grade Al is the practical limit. I had to use my handy flange bending tool (see 2 Jan 2013) to finish the 90 degrees.
12 Nov 2013 (1 hour, total time to date: 989.0 hours)
I did a lot more thinking and chatting than building today. I had a very helpful discussion with my good friend Tom (FAA DER) about my delemma regarding whether to splice the center skin at the top of the wing carry-thru flange. The idea of reaching down over 20 inches inside the cockpit to drill & rivet components (seat support, control fittings, etc.) is not very appealing to me. Also, it seems like a recipe for mistakes. The bigger question is: are there any structural concerns that I haven't anticipated. I can see two ways to splice the skin. 1) bend a flange on each side of the skin (just like the lower tail cone skin), or 2) install a separate doubler & butt the skins along the seam. Option 1 is a little problematic because I do not want to notch my carry-thru doubler and certainly not either BH flange. I want to be able to pull the skins up tight and flush and need some stiffness to accomplish it. Also, I can use the flange at the splice as an attachment point for the flap/trim tab contols. Option 2 will be a better fit to my requirements. I normally go with one guage thicker material for a situation like this (hence, my choice of the 0.04 doubler). The vertical load from the wings will (for practical purposes) runs up BH73.75 flange just above the upper carry thru flange. The first rivet hole is approx. 0.5 inches above the flange. This leaves approx. 16.5 inches to transfer 5500 lbs along the flange line. That works out to 333.3 lbs/in. It's an interesting coincidence that I generaly assume AN426-4 rivets should be good up to 333 lbs ultimate strength - even though higher values are provided in the literature. This certainly explains the 1 inch rivet spacing provided in the construction guide. Now, to explain how I came up with the 5500 lbs? I used a max gross weight of 1100 lbs x 1.1 (to account for the stabilizer down load) x 9 G's (ultimate), divided by 2 (each side) and rounded up to 5500 lbs. Now, this shear load will essentially be split between the forward & center skins (well, a little more in the front skin since the CG is a couple of inches forward of BH73.75). Anyway, I called it even. Because of my added carry-thru doubler, the vertical shear enters each skin (forward & center) thru 2 rows of rivets up the first ~10 inches, then transitions through the single line along the BH flange. However, the skin will still see ~166.7 lb/in shear ultimate. This is peanuts for 0.032 2024-T3 (5.21 ksi). One more important thing I want to add now is that Tom corrected my thinking related to the "toe of the boot" in the carry-thru doubler. I sucked myself into becoming "doubler happy," and I want to fess-up. The reason I added the "toe" was to connect/hold to the lower engine mount stringer/intercostal in place, and I thought, "hey, doublers are great, lets take some load out through them." Not so fast..... If I attach a line of rivets along the lower stringer/doubler, that provides an alternate load path though the doubler and will result in a "kick load" (get it, boot, toe, kick load, hehehehe) that will want to pass through the doubler accross BH73.75. I don't want that. Doublers are load magnets. Sometimes that's good, and sometimes it's not so good. The original design ends the lower stringers along the forward skin - this forces all of the lower axial load to shear out into the forward skin. There are 8, -4 rivets called out to connect the engine mount to the stringer. This means that the engine mounts can transfer as much as 8 x 333.3 lbs into each stringer - call it 2700 lbs ultimate. Imagine that, suspiciously close to 5500/2 - what a coincidence! It should never get there in reality since there is other weight between BH73.75 and the firewall. This does make you think a little about any ideas to strap a honking big engine on the front of the Midget. Once you start going above 1100 lbs GW, this should get your attention - and I've only looked at the rivet loads along the flange of BH73.75. So, the bottom line for me is that I will not be using the toe as I originally thought. I will cut it short, and attach 2, -3 rivets along the 1 inch edge of the stringer just to hold it in position when I wrap the forward skin around. I just don't want to go through the gymnastics suggested in the construction guide to attach the lower stringer aft end. The doubler can handle what little kick load those rivets can dish out. Ok, I've gone on enough, but please remember I'm not suggesting that anyone else do what I'm planning to do.
For the work accomplished, I bent the flange in the second center skin splice doubler. Also, I laid out the template on the center skin blank.
For the work accomplished, I bent the flange in the second center skin splice doubler. Also, I laid out the template on the center skin blank.
13 Nov 2013 (1 hour, total time to date: 990.0 hours)
Now that I have the skin template in good shape, I transferred the pattern to the 0.032 aluminum sheet. It was pretty tough bending the 0.025 tail cone skin, so I'm not looking forward to bending the center skin. Also, I spent some time re-fitting the template on the airframe. I'm trying to figure out the best way to install the skin between BH73.75 & 99.35. It's a very tight squeeze. The cardboard template has a lot more "give" than the real thing. Also, I'm still thinking about the skin splice. It will add weight, and I am a little concerned about the splice being so close to the applied vertical load at BH73.75.
14 Nov 2013 (1 hour, total time to date: 991.0 hours)
I realized that I may need one more drilling template to lay on top of the forward bottom (tunnel) skin at the bottom of BH73.75. I cut & match drilled the additional template. I also gave more thought and had more discussions about my skin splice idea. I decided to go forward, but will replace the existing carry-thru doublers with what I think is a better design (with the splice in mind). I drilled out the doubler holding rivets along the upper flange of BH73.75.
15 Nov 2013 (3 hours, total time to date: 994.0 hours)
I removed the longerons & BH73.75 from the jig, & marked/cut-out a duplicate of the lower doubler (will use it as a drilling guide for the lower skin). I then drilled out the lower holding rivets for the old carry-thru doublers. Using the old doublers as patterns, I laid out the patterns for the new doublers & made the updates (shorter toe & tab behind the BH). I cut out the new doublers, finished the edges, & cut/finished the hole in each to accommodate the upper wing attach lug. I then drilled the pilot attachment holes in the left doubler using the old left doubler as a drilling guide.
16 Nov 2013 (3 hours, total time to date: 997.0 hours)
Match drilled the pilot attachment holes in the new right doubler. With BH73.75 on the bench, it was a good time to match drill the duplicate lower doubler. I cut a piece of RAM BOARD to simulate a layer of skin (the material is also 0.032 thick) & placed it between the doublers before match drilling/clecoing the aft row of #41 pilot holes. Then I used a strap duplicator to find the hole nearest the center (I picked the right side), clecoed it, then found the two outside holes. I only needed to find two holes, but I wanted to be sure that I had the duplicate pulled in snugly by having one in the middle. I then removed the duplicate & used the appropriate drilling guide (see 23 Oct) to match drill the remaining holes. To check it, I replaced the duplicate with the RAM BOARD back on the lower doubler - fit like a glove! Now, I'll have a drilling guide to cleco to the accessible aft doubler holes which will make it much easier to locate the holes along the bottom flange of BH73.75 while I'm on my back trying to squeeze between the jig and the bottom of the plane. I then replaced the new carry-thru doublers on BH73.75, & installed 4 NAS1097-3's along each side to hold the doublers to the BH for construction. Now, I'm pretty much where I was last week, but with the new doublers and a better drilling guide for the bottom attachment holes. Finally, I replaced the BH back on the fuselage jig.
17 Nov 2013 (4 hours, total time to date: 1001.0 hours)
Trimmed the skin splice doublers to fit inside the BH flanges. Clamped the doublers in position, verified they were level, & MMD'd the #41 attachment holes in the doublers. I also laid out a staggered rivet pattern for the two rows of skin attachment holes. I drilled a portion of the holes in the forward and aft sides of the doublers, but will wait until I locate the seat BH to finish. I may need to cut a notch in the doublers to accommodate that BH flange. I replaced the doublers & match drilled the attachment holes.
18 Nov 2013 (1 hour, total time to date: 1002.0 hours)
I moved the doubler clecos to the inside of the cockpit, and replaced the cardboard lower skin template. I cut notches in the aft end of the template to fit around the rear spar to allow me to slide the template aft to accommodate the cut-out tabs between the wing attach fittings. I can't think of any other way to install the skin. This will result in openings in the lower skin in front of the rear spar (on each side). I will minimize this as much as possible, but will have to patch the area with small external doublers that will be covered by the wing root.
This method worked, and I used cargo straps to pull the template snug. I also wanted to check the fit of the seat supports.
This method worked, and I used cargo straps to pull the template snug. I also wanted to check the fit of the seat supports.
19 Nov 2013 (2 hours, total time to date: 1004.0 hours)
Removed the lower cardboard skin template and the splice doublers. Drilled the remaining pilot attachment holes in the doublers & replaced them on the frame. Started fabricating test specimens to compare the strength of a butt vs. lap splice along the doubler. I want to look at the out-of-plane bending effects for the different configurations as well as the possible benefit of using universal head rivets (perhaps along the lower row). The specimens are 2.65 x 10 inches to accommodate two rows of three rivets. For the staggered lap configuration, I will install -3s on each side of the lower row where there are 2 -4's. That's about as close as I can get to simulating the continuous staggered pattern.
20 Nov 2013 (2 hours, total time to date: 1006.0 hours)
Continued fabricating 4 test specimens. 1) 2-row lap splice w/o the doubler angle 2) butt splice 3) 2-row lap splice (all holes dimpled) 4) 2-row lap splice (lower row not dimpled - using AD-470's). I finished drilling all of the fastener holes to final size.
21 Nov 2013 (2 hours, total time to date: 1008.0 hours)
Finished specimen fabrication and ran static tests to failure. The lap joint with 2, staggered rows of fasteners performed as I had expected/hoped - approx. 2x better than the single row butt joint. The 0.040 thick stiffened (flanged) doubler increased the strength slightly. Two things worth noting are that the universal head rivets held the lower seam to the joint, but failed sooner (you can see when the first two popped). The C/S rivet heads deformed prior to failure and allowed the load to be redistributed (although there was significant edge deflection due to out-of-plane bending). Adding a third row of holes would result in nearly matching the raw tensile strength of the 0.032 sheet.
22 Nov 2013 (1 hour, total time to date: 1009.0 hours)
Triple-checked the cut lines on the center skin sheet (added the rear spar cut-out) using the cardboard template & marked the areas that will need to be "rolled." Then, I trimmed the front & back sides of the center skin. I left approx. 3/16 oversize just to give me a little "cushion" for the final trim & finish after the pilot holes are drilled. I didn't cut the notches - will wait until I have the skin formed to the approximate shape. I also started forming the bottom skin using a 4 inch PVC pipe. I marked the areas to be formed, clamped the pipe on top of the skin (on my work table), and carefully rolled/pulled the skin around the pipe. Leaving the skin stock long for now is helpful in providing more leverage for forming the skin around the pipe.
23 Nov 2013 (3 hours, total time to date: 1012.0 hours)
Made a few more adjustments to the contour of the lower skin to better match the curvature of BH73.75 & 99.35. Just a matter of shifting the location of the PVC on top of the skin & applying more or less elbow grease. Once I had the contour the way I wanted it, I used a cut-off wheel on my die grinder to cut the sides off (I left about an inch on each side to be safe). Then, I used my Dremel cut-off wheel to make the cut-outs for the wing attachment lugs & rear spar. The reason for the rear spar cut-out was simply because I couldn't think of another way to get the skin on the frame while it's in the jig. I've been trying to think of another way for the last few weeks, and came up empty. I don't want to risk messing up the fuselage alignment & I'll need to take the skin on/off many times during the build. What works for me is to insert the lower skin between the BHs & under the splice doubler (with the forward side down). Fit the aft side between the vertical supports & the tail cone skin, sliding the aft cut-outs through the rear spar. It's a great idea to put some duct tape around the corners of the vertical supports (and the skin in this area) to keep them from scratching the skin (it's tight in there). You need to flex the skin open in front to allow enough clearance to get the aft side under BH99.35 (It's a good thing I decided to make the jig 4 inches higher, or I don't think this would be so easy). Slide the skin aft as far as the aft cut-outs allow (I made a few iterations on the depth of those cut-outs as well), rotate the forward end up around the wing attach lugs, and slide the skin forward to get it in place. The first time I tried this, I had to remove the lower wing attach cap screws, but after a few adjustments, I got to the point where the skin will clear them. It took several iterations before I was happy with the fit (the cardboard template was invaluable for me to get this all done). Once it was in place the first time, I could mark the location of the BH flanges and doublers to be sure I was going to have good edge margins for any additional trimming to make the fit easier. I cut "dog ears" in the corners of the wing attach cut-outs to get around the cap screw heads. Also, I'll probably be cutting the skin down to the top of the upper lug (also the top of the splice doubler flange) at some point, but I'm currently keeping my options open. The thing I don't like about the rear spar cut-outs is that you end up with an open "hole" in front of the rear spar on each side once the skin is in place (~0.75 wide x ~1.2 high). The good thing is that they will be hidden by the wings, and I can extend a strip on the center side skins to use as a repair doubler. There are also handy flange tabs on BH99.35 right there as well. Others may have thought of a better way, but this is working for me. It seems very odd that I can't find any info on how anyone else has done this in the past, but the bottom line is that it isn't easy getting the skin around the BHs and jig structure.
24 Nov 2013 (3 hours, total time to date: 1015.0 hours)
Trimmed the forward & aft sides of the lower center skin to approx. 0.5 in. from the rivet lines. This will make it a little easier to fit the skin between the BHs, & I'll do the final trim after the attachment holes have been drilled. I also cleaned up the corners of the cut-outs using the Dremel with 1/4 in. sanding drum. I spent some time finishing the edges of the cut-outs. Then, I replaced the splice doublers to check to be sure I could replace the skin with them in position. No problem, so I "tack riveted" the doublers in position with a few -3's & replaced the lower skin in preparation to drill the skin attachment holes.
25 Nov 2013 (1 hour, total time to date: 1016.0 hours)
I decided to remove the lower skin again and make some slight adjustments to the curvature of the skin around the rear spar cut-outs. The skin was slightly pulling away above the rear spar. In the process, I found a few more places that could use a little tape to protect from scratches. I made some adjustments, added some tape, and replaced the skin. The fit was a little better, but I don't think I can expect a perfect fit.
26 Nov 2013 (1 hour, total time to date: 1017.0 hours)
Used cargo straps with 1x2s under the skin to pull the lower skin tight against the BHs. Working from the C/L, I drilled #41 pilot attachment holes along the lower doubler and the lower flange of BH99.35. Before going further, I will need to remove the skin, and use the doubler template (made on 16 Nov) to locate/drill the attachment holes for the lower flange (BH73.75). Also, it looks like I will need to trim the lower aft edge of the carry-thru doublers where they overlap the splice doublers to allow the skin to sit closer to the BH flange between the wing attach fittings. I will also need to remove the angle support brackets between the wing attach fittings to allow access to the attachment holes on the flange.
27 Nov 2013 (1 hour, total time to date: 1018.0 hours)
Removed the lower skin, trimmed, & cleaned-up the edges of the BH/splice doublers. Also, cut/finished a slight taper along the bottom flange edges of the spar carry-thru diagonal braces. This will provide needed clearance with the lower skins (center and forward). The lower corners do not serve any structural purpose & can scratch the "heck" out of the skins.
28 Nov 2013 (2 hours, total time to date: 1020.0 hours)
Traced the contour of the lower flange of BH73.75 on a scrap piece of 1x4, cut, & sanded it as a male form to help locate the skin attach holes. I triple-checked the duplicate lower doubler template fit on the lower flange, clecoed it to the aft doubler attach holes in the bottom of the center skin, & clamped the wood form to the inside along the flange line. I match drilled the flange attachment holes through the template (using the reflection of the drill bit to keep it normal to the skin curvature). Marked a trimming line 11/32 from the flange attach holes (just to leave a little room - will do the final finishing later). and trimmed/finished the edge. This didn't remove much, but makes it a little easier to get the skin on & off. Finally, I marked/trimmed the aft edge of the skin in the same manner.
I have an issue around the wing attach fittings to resolve. There is very little access on the outside due to the BH supports,, and the angle brackets are blocking access from the inside. The obvious solution is to remove the brackets, but the bolts are a very tight fit (as they should be). However, I need to pull the skin to the flange, drill the attachment holes, & tack rivet one of the holes before I can fit the forward skin over the top. Also, I would like to have the skin formed nicely around this area before I drill the pilot attachment holes along the splice doubler - don't want to run the risk of buckling the skin if I pull it against the frame after the other holes are in place. Unfortunately, there are no other helpful hints in the construction guide, so it looks like I'll need to come up with a good way to press the bolts out of the brackets so I can get them out of the way.
I have an issue around the wing attach fittings to resolve. There is very little access on the outside due to the BH supports,, and the angle brackets are blocking access from the inside. The obvious solution is to remove the brackets, but the bolts are a very tight fit (as they should be). However, I need to pull the skin to the flange, drill the attachment holes, & tack rivet one of the holes before I can fit the forward skin over the top. Also, I would like to have the skin formed nicely around this area before I drill the pilot attachment holes along the splice doubler - don't want to run the risk of buckling the skin if I pull it against the frame after the other holes are in place. Unfortunately, there are no other helpful hints in the construction guide, so it looks like I'll need to come up with a good way to press the bolts out of the brackets so I can get them out of the way.
29 Nov 2013 (3 hours, total time to date: 1023.0 hours)
I fabricated another drilling template to locate the last (furthest outboard) skin attachment holes on the bottom flange of BH73.75. I didn't make the lower doubler wide enough to reach these holes for 2 reasons: 1) the radius of curvature is becoming small, and 2) the forward bottom skin does not extend to this location. Once I had duplicated the holes in the doubler, I used a strap duplicator to find the last 2 holes. I then transferred the holes to the lower center skin. I was also able to reach Chris at MA regarding my issue with the attachment holes between the wing attach lugs. He convinced me not to remove the "butt angles." After thinking about the alternatives (not many), I will wait until I remove the skin/doublers for dimpling & back drill these skin attachment holes through the doublers. This means that I will not be able to use rivets in these holes. Chris suggested Cherry Max, but I will see about using #6 nut plates (since I will also be able to remove the BH). I pulled the lower skin snug with cargo straps, inserted wood spacers between the straps & skin in a few locations to get a good fit around the BHs, clamped a 1x2 along the outside of the skin (along the splice doubler), and drilled out the skin attachment holes along the left doublers. Looks like a good fit!
30 Nov 2013 (1 hour, total time to date: 1024.0 hours)
Repeated the process from yesterday & drilled out the pilot attachment holes in the lower center skin along the right splice doubler.
1 Dec 2013 (2 hours, total time to date: 1026.0 hours)
Removed the lower skin & marked trimming lines 3/8 in. from the top and aft row of fastener holes. Trimmed the skin just shy of the lines using a cut-off wheel on my pneumatic die grinder. I used a sanding disk to clean up the cut up to the line, and finished the edges with a Perma-Grit block sander, #60, #150, #220, and finally some scotch brite. After finishing all of the edges, I replaced the lower skin on the airframe.
I'll be taking a few days off for a business trip. I plan to get back to work on Friday evening.
I'll be taking a few days off for a business trip. I plan to get back to work on Friday evening.
6 Dec 2013 (2 hours, total time to date: 1028.0 hours)
Now, I need to turn my attention to the firewall so that I can fit the lower forward fuselage skin. I marked the firewall attach plates (1 thru 4) & outlined the footprint of the engine mount brackets. I cut pieces of 1x2 to support the firewall on the work table. Removed the firewall & laid it on the table. Marked the rivet line between the engine mount holes, inserted AN6 bolts in each hole, replaced the mount brackets, and taped them in place. Measured/cut the top & bottom firewall angles to length, then finished the ends. Marked the C/L on the angles, laid out, & drilled the pilot attachment holes in the bottom angle as shown in the plans (Dwg 4). I managed to maintain just over 0.25 in. edge margins at the ends of the angle & brackets and squeeze out 13/32 spacing for the 3 rivets in the brackets. Finally, I laid out the attachment holes in the top angle.
7 Dec 2013 (4 hours, total time to date: 1032.0 hours)
Cut the bottom firewall angle filler strip & finished the edges. Taped it in place, taped the angle on top, & match drilled the pilot attachment holes through the angle/firewall (clecoing in place as I went). Drilled the pilot attachment holes in the top angle, & repeated the process. Cut the left & right angles to length, laid out the attachment holes, and repeated this process for both sides. Finally, I removed the bolts/angles/filler strips, de-burred the holes, & replaced the angles/filler strips on the firewall.
8 Dec 2013 (2 hours, total time to date: 1034.0 hours)
Replaced the firewall on the fuselage jig using AN6-27A bolts (a little longer than what I'll use to attach the engine mount, but the spacers are longer than the engine mount attachment). Clamped the forward lower skin (tunnel) in position & checked the fit. I also ran a plumb line down to verify the C/L on the lower doubler at BH73.75. Removed the tunnel and the lower firewall angle. Marked the location for the outboard attachment holes on the lower angle for the tunnel, laid out the fastener locations (I used a 1.8 inch spacing for all of the fasteners), & drilled the pilot holes through the angle. Replaced the angle on the firewall, marked the C/L on the tunnel, & clamped it back in place. Made some adjustments to get the tunnel aligned - checked & double checked.
9 Dec 2013 (1 hour, total time to date: 1035.0 hours)
I used a cargo strap to pull the aft end of the tunnel flush with the bottom doubler (not too tight, just snug), checked the fit one more time, & match drilled the #41 pilot attachment holes through the lower firewall angle. I removed the tunnel & laid out the sides of the tunnel to determine how to trim the tunnel flanges to allow the sides to nest inside. It makes more sense to attach the sides along the inside of the tunnel flanges since it's a lot easier to seal the joint (I may run a single exhaust out of the bottom), and looks much better from the outside). In addition, this provides a better structural connection toward the aft end where there is no room for any fasteners due to the taper required in the flange (the sides will wrap around the flange). I trimmed the tunnel flanges along the aft end as required, & finished the edges. I'll take a picture once I get the sides on the tunnel.
10 Dec 2013 (2 hours, total time to date: 1037.0 hours)
Replaced the tunnel on the lower firewall angle & held the sides in place to determine how to trim them to line up with the lower firewall skin attach flange. The side flanges also need to be bent further to align with the angle of the lower firewall flanges. I marked the sides, trimmed the edges with a cut-off wheel, and finished with a sanding disk. This took a few iterations since it's always easier to take more material off than to put it back. I removed the tunnel & checked the fit of the sides. Since the sides were trimmed, the tunnel flanges also required some trimming to match. Again, more iterations..... Then, I clamped sides between some scrap plywood in my bench vise & used a rubber mallet to add a little more angle to the forward end of the side flanges. I replaced the tunnel & checked the fit of the sides to the lower firewall flanges. A little more adjustments are required, but it's almost there.
11 Dec 2013 (1 hour, total time to date: 1038.0 hours)
Removed the protective plastic on the inside of the tunnel flange (the plastic had become wrinkled in the inside corner), checked the fit of the tunnel sides, and did a little more sanding of the flanges for a better fit. Before drilling the attachment holes for the tunnel sides, I wanted to be sure that the forward tunnel flange holes could be drilled through 1x1 angles that fit along the sides of the firewall cut-out. I fabricated the angles to fit along the sides, finished the edges, drilled the pilot holes, & match drilled the angles in place on the firewall. I then verified that the forward upper holes for the tunnel sides can be drilled through the angles with proper edge distance & are accessible for assembly. If this wasn't the case, I'd have to attach the sides to the angles below the tunnel flange, & drill the hole through the tunnel flange aft of the angle. I'll lay out/drill the tunnel flange attachment holes tomorrow.
12 Dec 2013 (1 hour, total time to date: 1039.0 hours)
MMD'd the attachment holes along the tunnel flanges for the sides. I clamped the sides in place, match drilled the #41 pilot holes, and clecoed the sides on the tunnel. The edge distances of the holes nearest the aft end will not support -4 rivets, so I will install -3s (I plan to add a few more later).
13 Dec 2013 (1 hour, total time to date: 1040.0 hours)
Clecoed the tunnel in place on the firewall & used a strap duplicator to locate the two attachment holes on each side of the C/L at BH73.75. I used a cargo strap to pull the tunnel up to the flange (not enough hands to do it myself). I drilled the two pilot holes & installed clecos to hold the tunnel in place. I did this to help hold the tunnel in position when I drill the pilot holes at the forward end of the bottom doubler. For what it's worth, I'll say this again (probably not for the last time): I am so very glad that I built the fuselage jig 4 inches higher than indicated in the drawings. Drilling the skin attachment holes along the bottom of BH73.75 is somewhat challenging. Too bad I don't have a hydraulic lift :-).
14 Dec 2013 (2 hours, total time to date: 1042.0 hours)
Laid out the fastener pattern for the tunnel along the fwd end of the bottom doubler (1.25 in. spacing worked very well). I trimmed the forward end of my duplicate bottom doubler to fit inside the tunnel, & clecoed in place using the existing holes. I then used my trusty cargo strap to snug the tunnel to the doubler. I needed to insert a scrap piece of 1x4 under the tunnel along the fastener line to hold the duplicate doubler against the tunnel. Using a scrap piece of 0.032 as a drilling guide, I drilled/clecoed the holes starting at the center, and working out on each side. Once this was done, I removed the tunnel & used the duplicate doubler to locate/drill the remaining attachment holes along the bottom flange of BH73.75. I also used the 1x4 that I had previously cut to match the curvature of the bottom flange while match-drilling the bottom holes. Not that it mattered, but I checked the holes with the 3rd drilling template (simulates the outer layer). Finally, I replaced the tunnel, & the fit was very good. I have been very concerned about getting the holes matched along the bottom flange of BH73.75. I may have overdone the drilling templates, but the extra work saved me some time today.
15 Dec 2013 (3 hours, total time to date: 1045.0 hours)
Trimmed & lightly finished the edges of the lower engine mount stringers. The lower stringers do not fit inside the butt angle flanges at BH73.75 as supplied by MA. They work well on the top, and it's not much of a job to cut the bottom two. They are not intended to carry load across BH73.75 (unlike the upper stringers that are designed to carry load through the upper longeron). they transfer load in shear to the forward side skins. That is why they terminate in the skin just forward off BH73.75. Since I don't want to provide a significant alternate load path across BH73.75, I will only attach the aft end of the lower stringers to the inside of the side doublers with a single rivet. I'll use a 1097-3 to simply hold the stringers in place - much easier than the method called out in the construction guide. I also trimmed the "toe of the boot" in the side doublers enough to allow room to clamp the stringers in place prior to drilling the attachment hole (I'll trim it again after this is accomplished). I also removed each firewall support angle & trimmed/finished (dog-ears) the corners of the outstanding legs to provide clearance to drill the attachment holes trough the engine mount brackets. I also trimmed the upper stringers to provide clearance around the rivet head holding the upper longeron to the "clip" at BH73.75. Finally, I clamped the lower stringers in place (level), and placed the upper stringers in place for the picture.
16 Dec 2013 (1 hour, total time to date: 1046.0 hours)
Fabricated a template from a scrap piece of 0.032 aluminum sheet to locate the fasteners on each side of the engine mount brackets. I made the template to match the size & shape of the brackets. I'll be able to lay the template on the outside of each stringer, mark the location of the holes, remove the stringer, & drill the pilot holes on the drill press. Started work laying out the pilot holes on the lower left stringer. In order for the stringer to be flush with the firewall flange & maintain good edge distances, I needed to trim/finish the edges slightly (the inside corners interfered with the firewall angles). This required me to re-level the stringer before I could determine a good location for a -3 rivet to hold the stringer in place at the side doubler. I drilled a #41 pilot hole approx. 0.75 in. forward of the butt angle (for access with the rivet squeezer).
17 Dec 2013 (1 hour, total time to date: 1047.0 hours)
Using the template I made yesterday, I marked the attachment hole locations on each side of the lower left stringer. In the process, I noticed that the forward stringer flanges are not symmetrical. Not a big problem, but it took a little more time to check edge distances on the engine mount bracket. There is also some twist along the stringer to remain flush at each end. I clamped the upper side in place & match drilled the aft pilot attachment hole. Then, I was able to install a cleco, removed the clamp & drilled the remaining 3 holes. I then repeated the process on the lower side of the stringer.
18 Dec 2013 (1.5 hours, total time to date: 1048.5 hours)
I fit the lower right engine stringer and drilled the pilot attachment holes using the same process used for the lower left side. Leveling the stringers is complicated by the twist & variability in the bend along the length of the stringer. I decided that it makes more sense to go for symmetry from side to side. After doing my best to level the left side, I ended up using a straight piece of 1x2 that fit between the tunnel floor at the aft end of the stringers. Since the tunnel floor was fairly level, I placed the 1x2 on the tunnel floor and slid it forward until it touched the bottom of each stringer at the same time. Of course, the success of that approach depends on each stringer being the same. However, I used the lower bend radius of each stringer (not the outside edge of the flanges) as the reference. I also checked this by "eye-balling" the projection of each channel wrt the bolts along the butt angle. In the end, I decided that would be good enough....
19 Dec 2013 (1.5 hours, total time to date: 1050.0 hours)
Before fitting the upper engine mount stringers, I wanted to check to see where the canopy seal intersects the stringers. To accomplish this, I needed to replace the upper instrument panel on BH73.75. I removed the longerons, replaced the IP, replaced the longerons, & clecoed the canopy seal in place. I then started work fitting the upper right stringer. I clamped the stringer in place, marked the forward end of the stringer for minor trimming to fit properly at the engine mount bracket. Trimmed/lightly finished the forward edge of the stringer, replaced it on the airframe, & laid out the location of the attachment holes. Removed the stringer, drilled the #41 pilot holes, and replaced it on the airframe again in preparation to match drill the holes through the brackets.
20 Dec 2013 (2 hours, total time to date: 1052.0 hours)
Clamped the right upper stringer in place on the engine mount bracket & match-drilled the upper, aft pilot hole. Removed the clamp & drilled the remaining 3 holes in the upper side. I found that the lower side was more difficult to reach without rotating the bracket to clear the firewall angle (even with the corners removed). Not really a big problem, just a little extra rotation to drill/cleco the holes. I drilled out the bottom pilot holes in the same manner as the top. I then duplicated the procedure for the upper left engine mount stringer.
21 Dec 2013 (2.5 hours, total time to date: 1054.5 hours)
Before removing the firewall to drill out the angle attachment holes to #30, I realized that I had not drilled the attachment holes for the tunnel sides to the short angles on the firewall. I marked the angle edges on the tunnel sides, removed the sides, located/drilled the lower attachment pilot holes, replaced the sides, & match drilled the holes through the angles. I then removed the tunnel, marked/drilled the additional #40 holes along the aft side of the tunnel (these are the additional attachment holes that I mentioned on 12 Dec). Then, I removed each engine mount stringer/bracket/bolt, clecoed each bracket to it's stringer (mostly to keep them together), used my disk sander to round the corners of the 2x2 spacer blocks to provide clearance to install the cowling attachment strip to the firewall flange, and attached each spacer to it's stringer with the jig mounting bolt (again, to keep them together). Finally, I started work drilling out the angle attachment holes on the firewall to #30 for assembly.
22 Dec 2013 (4 hours, total time to date: 1060.5 hours)
I drilled the firewall angle attachment holes to #30 in 2 steps. First, I drilled the holes out to 0.125 & de-burred the holes on the engine (exit) side. Then, I finished each hole to #30. I decided to do it this way because the holes in the firewall (steel) had more of a "lip," and I wanted to remove it before finishing the hole. I didn't want to C/S the holes in the very thin steel, so opening up the holes from 0.125 to 0.128 would help clean up the holes and remove all/most of any C/S I may have caused by de-burring (I used a de-burring bit on my hand drill). I then removed the angles/corner braces, de-burred all of the holes/edges in the aluminum, cleaned them with acetone, marked each piece for re-assembly, and scuffed the surfaces with scotch brite. Finally, I de-greased the parts and painted the mating areas with Superflight Lycoming Grey (good to ~400 degrees F).
23 Dec 2013 (1.5 hours, total time to date: 1062.0 hours)
Re-assembled the firewall components & started riveting the corners. Using my longeron yoke, I can reach the corners and the lower rivet line. I installed rivets in each corner and the rivets holding the angles along the tunnel sides. If I have time tomorrow (Christmas Eve), I'll experiment on some scrap angles with an idea I have to back rivet some universal heads on my work table. If successful, I'll be able to finish the riveting work on the firewall without asking for extra hands.
24 Dec 2013 (2 hours, total time to date: 1064.0 hours)
I drilled a 3/16 in. hole in the edge of one of my heavy tungsten bucking bars just deep enough to accept my 1/8 cupped rivet set. This provides the mass needed to react the impact from the rivet gun to set the rivets. I practiced back riveting several holes in some scrap aluminum angle stock using a 1x2 & a piece of thin plywood to level the angle on the bucking bar. This worked well, so I used the same method to buck the rivets along the upper angle on the firewall. I took my time - made sure I had the firewall level and had each rivet head securely seated in the cup. I positioned the edge of the firewall just over the edge of the work table so I could see that the rivet was in place before pulling the trigger. I'm happy with the results so far.
25 Dec 2013 (2 hours, total time to date: 1066.0 hours)
Merry Christmas! Finished back riveting the firewall. This method worked very well - allowed much better control of the shop heads. Very consistent results.
26 Dec 2013 (1 hour, total time to date: 1067.0 hours)
Turned my attention to the engine mount stringers. I thought I'd rivet the stringers to the brackets before replacing the firewall. I'll need to do it before I can fit the forward fuselage skin, so now is probably a good time to get this done. I drilled out the attachment holes in multiple steps (again, in hope of minimizing the amount of de-burring work for the steel brackets). De-burring the inside of the brackets is a bit difficult. I started working on them with a tapered Dremel grinding bit that I cut short.
27 Dec 2013 (3 hours, total time to date: 1070.0 hours)
Well, the dremel bit shaft was too small to turn by hand and properly deburr the holes - especially in the steel brackets. I decided to cut off the 3/16 threaded shaft on a deburring bit and give that a try (polished the nub to prevent scratching the parts). This worked much better, but I needed to insert a shim inside to help apply a little pressure as I turned the bit with my fingers. It was still tedious, but it's important to clean up the holes. Nitrile gloves also helped give me better grip. I removed the plastic on the inside of the channels and on the outside in the area of the bracket attachment, and de-burred the holes in the stringers. Finally, I polished the exposed aluminum in preparation for anodizing. I plan to do that tomorrow and apply some pro seal between the aluminum and steel as I rivet the parts together. My brackets are powder coated, but I still feel better using pro seal to keep the steel and aluminum isolated.
28 Dec 2013 (3 hours, total time to date:1073.0 hours)
I assembled the tunnel & drilled out the attachment holes for the tunnel sides, removed the plastic in these areas, & de-burred the holes/edges. Since I am going to use pro seal on the stringers and tunnel sides, now is the time to prepare the tunnel for assembly. However, I left the forward holes slightly undersized (o.125) since I will be match drilling the attachment to the firewall support angles. I then finished the mating surfaces of the tunnel/sides with scotch brite. I then acid etched & alodined the stringers and tunnel pieces. Finally, I checked to be sure that I had the proper rivets/lengths to assemble the parts. I had to cut rivets to length for the tunnel.
29 Dec 2013 (3 hours, total time to date: 1076.0 hours)
I mixed up the pro seal, applied a light coating to the outside of the engine mount bracket, and the inside mating surfaces of the corresponding stringer. I made sure to coat the inside corners of the stringer in the area of the bracket. I then slide the appropriate bracket inside it's stringer, installed a few clecos to hold it in place, and started squeezing the rivets. I used nitrile gloves to apply the pro seal (the finger applicator works best). The gloves are great, but I still ended up with pro seal on my fingers since I took off the gloves to handle the squeezer (it's hard to avoid touching something with pro seal on it). Acetone works well to remove the pro seal from places you don't want to be coated, but I'm glad I was wearing old clothes. Since the rivets are relatively close together, I couldn't have a cleco installed in the adjacent hole (interfered with the squeezer body). I installed rivets in the adjacent holes to help keep things lined up. I squeezed the end rivets first, then the inner ones - removing clecos and installing rivets as necessary. Also, it was helpful if the hole opposite the hole being riveted did not have a cleco installed (more room for the squeezer). When I finished all 4 stringers, I coated the mating surfaces of the tunnel/sides, and installed the rivets. I did not rivet the forward holes since they will be attached to the firewall angles later. In the meantime, I clecoed the edges while the pro seal cures. The main reason for the pro seal in the tunnel is just my attempt to help keep exhaust gases out of the cockpit in case I run the exhaust out of the bottom of the A/C. Finally, I used acetone to clean up my grubby pro seal fingerprints that were all over the parts.
30 Dec 2013 (1.5 hours, total time to date: 1077.5 hours)
Started work replacing the firewall, engine mount stringers, & tunnel. Replacing the firewall includes replacing the stringers since the attachment bolts must go in from the stringer side. This proved to be a bigger job than I had expected. I knew the fit around the rivet shop heads would be tight, but didn't think about what that would mean for the actual installation. I used a stainless steel washer under the head that made it a little more difficult, so I'll probably replace them with thinner washers for the final installation. Anyway, there is very little clearance around the bolt heads due to the inside dimension of the brackets, and the shop heads are relatively close (~0.2 in. or less) to the base of the fittings. I customized a 9/16 wrench to fit as shown in the picture. The bolt heads have to be oriented so that parallel edges are parallel to the fitting flanges. The new tool does a good job of holding the nuts, but I wouldn't (even if I could) try to torque the nuts with it. Anyway, I got the bolts snugged up nice and tight with the stringers aligned with the curvature of the firewall flange. It's looking more and more like an airplane every day. :-)
31 Dec 2013 (1 hour, total time to date: 1078.5 hours)
Replaced the tunnel on the airframe & installed 1097-3 rivets to hold the aft end of the lower engine mount stringers in place on the side doublers. I also started laying out the rudder pedal hardware for fit up on the tunnel.
1 Jan 2014 (1.5 hours, total time to date: 1080.0 hours)
Cut out and bent the flanges for the 0.040 tunnel reinforcement (for mounting the rudder pedals - this was not included in the kit). I tapered and finished the corners of the flanges & marked the C/L. In order to attach the rudder peddles, I ground/polished the rudder peddle attach tubes to fit inside the pedal brackets. I used 3 in. long 0.25 dia. bolts to attach the pedals & test fit the nylon bearing blocks. The plans call for the rudder pedal axle to be centered at FS156.5, but I will check to be sure that the pedals will not strike the firewall at maximum deflection with the toe brakes engaged.
2 Jan 2014 (2 hours, total time to date: 1082.0 hours)
Removed the pedals from the assembly & positioned the assembly/mounting blocks on the tunnel reinforcement. I clamped (not too tight, but enough to hold) the axle in place, removed the upper halves of the bearing blocks, and drilled the attachment holes through the reinforcement. I did this in 2 steps to minimize damage (over-sizing the holes) to the mounting blocks. The first step was to use a #19 drill bit with painters tape around the shank to center the bit and help protect the block (leaving room around the tip of the bit for aluminum shavings). Then, I used a 3/16 bit to finish the holes. I drilled through the blocks, but having the pilot hole, greatly reduced the shavings and amount wear in the nylon blocks. Then, I found the longitudinal C/L of the reinforcement, & drilled #41 attachment pilot holes on the C/L (same spacing as the 3/16 holes). I replaced the reinforcement/assembly on the tunnel, inserted 3/16 bolts to engage the holes in the reinforcement (to hold the axial in place), centered the pilot holes on the tunnel C/L, measured back 4.5 inches from the firewall to the C/L of the axle (I used duct tape to hold the reinforcement in place), double checked to be sure the 3/16 holes were centered on the tunnel, & match drilled/clecoed the C/L pilot holes through the tunnel. This position allows for 0.5 in. of forward travel at the rudder cable attachment with the toe rotated forward for braking. I removed the reinforcement & laid out/drilled additional attachment holes (a spacing of 1.75 in. worked well) along the forward and aft sides of the reinforcement (two additional rivets on each side of the C/L (fore and aft). Finally, I replaced the reinforcement, drilled out the additional #41 pilot holes, & match drilled the 4, 3/16 holes through the tunnel for the mounting blocks. I am temporarily using #10 machine screws to hold the assembly in place.
3 Jan 2014 (1 hour, total time to date: 1083.0 hours)
Started work laying out the seat support. I called Chris at MA because I noticed a discrepancy in the plans on the location of the seat support BH. Dwg 2 indicates that the web is located at FS83.75, & dwg 22 indicates FS84.35. Chris told me that he believes that FS83.75 is the correct position, but the kit seat bottom should dictate the position since the rear flange is mounted to the lower web of BH99.35. Since the seat bottom is 15.5 in. long, the actual location would work out to 83.85 (assuming the seat BH flange is to the rear of the web). If the seat BH flange is fwd, then FS84.35 would be the location of the web. The torque tube for the flap control is mounted off of the seat BH, so I wanted to accurately locate the BH. Chris stated that the flap control arms can be adjusted to account for +/- 0.5 in., so I will take another look at them before drilling any holes in the skin. However, I did notice that the seat BH seems to fit better in the further aft location. I also ran a wire between the rudder control horn to the rudder pedal cable attachment to note the path of the cable under the seat (I want to be sure to locate the longitudinal seat supports so they will not interfere with the cables).
4 Jan 2014 (1 hour, total time to date: 1084.0 hours)
The direct path between the rudder pedal cable attachment and the rudder control horn interferes with the flange of BH160. In addition, that path places the cable at the inside edge of the cable pass thru holes in BH177.5. It looks like it may be better to route the cable through the web of BH160. In this case, the cables would be a little further from the C/L between BH73.75 & 99.35, and centered in the pass thru holes. In any case, I know the approximate spacing required for the longitudinal seat supports. I continued fitting the seat BH, but it looks like the flanges will not lay flush against the bottom skin. I will need to fabricate a new one to fit. Finally, I removed the left upper stringer and left longeron because I noticed that the left longeron was not seated well in the inside lower corner of the stringer. I rounded the outside lower edge of the forward section of the longeron so that it would seat better inside the stringer. I replaced the parts, and am happy with the fit.
5 Jan 2014 (3 hours, total time to date: 1087.0 hours)
I started work to fabricate a new seat bottom BH. I believe the reason the kit part did not fit well was due to the fact that I rolled the bottom skin around PVC pipe. Not really a big deal, just takes a little more time to make a new one. I'd much rather have a good fit than to have the skin pull in around the rivets. I used the original part to trace a template on a piece of RAM Board (making adjustments in the necessary areas). I transferred the pattern to 3/4 hardwood plywood, & cut it out. I used a strip of RAM Board inside the seat bottom to simulate the thickness of the flange, & tweaked the form to get a nice fit (the first piece will be used as the backing board for the forming process). Then, I traced the pattern on another piece of plywood, cut/finished it, & cut out a piece of 0.032 sheet for the new BH. I laid out the approximate location of the stand-off attachment tubes for the flap actuator torque tube. Before locating the tooling holes, I wanted to be sure that I didn't have the tooling holes too close to this area. It was a very good thing to check because Dwg 25 indicates that the stand-offs are 15.5 in. apart (on center). This is not correct! The inside measurement of the bottom skin at the torque tube is approx. 21.5 in., and the flap handle is welded to the torque tube at approx. 7.75 in. from the C/L. The stand-off attachment tubes can not be located in the same place. I assume this was a simple mistake, since there is an unmarked dimension to the flap handle on that drawing. It looks like ~12 in. between centers will be about right for the stand-offs. It definitely pays to check things carefully.
6 Jan 2014 (3 hours, total time to date: 1090.0 hours)
I decided to use 4, 3/16 bolts to hold the seat BH forms tightly together. I placed 2 along the A/C C/L, and 2 more on the outside corners, 3-3/8 in. above the bottom of the BH (this is the location of the C/L of the flap actuator torque tube). The bottom hole will be enlarged later to accommodate the elevator push rod, and the other hole is also along the C/L of the torque tube. I drilled the tooling holes in the male form, then match drilled the holes in the backing board. I then positioned the 0.032 sheet blank on the male form & match drilled the tooling holes. I then, traced the BH pattern on the sheet, laid out the flange tabs (symmetrically), & drilled 3/16 holes for the tabs along the bend line. I also decided to fabricate a duplicate blank (just in case) since it was easy to trace, cut, & match drill a copy before cutting out the tabs. I cut the tabs in one blank, cleaned up the edges, replaced the blank between the forms, clamped the assembly in a bench vise, & used a rubber mallet to bend the flanges. Once this was done, I finished the bends using my hard wood flanging tool (see 2 Jan 2013). The fit was very good, but I'll hold onto the extra blank and forms.
7 Jan 2014 (1.5 hours, total time to date: 1091.5 hours)
I worked on a couple of smaller tasks today - it's been really cold in the garage (I need a better heater). Anyway, I needed to clear out the inside of the tubes on the stand-off mounts for the flap actuator. I don't have a 0.75+ reamer, but I have a dremel wire brush tool that worked very well. It just fit inside the tubes, and really cleaned up the inside where the tube was welded. I also used some fine sand paper and steel wool to finish it off, and applied a thin layer of 3 in 1 oil. I also cut 2, 2x4s to hold the seat back BH in place for attachment to the skin. My question about the location were answered by the length of the kit supplied longitudinal support. It is designed to attach between the seat support and BH99.35 (problem solved). This placed the seat support web 15 inches forward of BH99.35. I decided to orient the seat support flanges aft so that I wouldn't need to cut a notch for the flap handle, or deal with an overhang under the forward edge of the seat. The seat bottom must be removable anyway, so I'll be installing nut plates along the upper flange. Finally, I removed the seat back BH and started drilling #41 pilot holes in the flange tabs in preparation for attachment to the skin.
8 Jan 2014 (1.5 hours, total time to date: 1093.0 hours)
Finished drilling the pilot holes in the seat bottom support flange except for the last tabs at the top of the BH. These holes will have to be drilled from the outside. I replaced the BH inside the cockpit, used the 2x4 blocks & longitudinal supports to position/align the BH, centered the BH on the A/C C/L (double checked that the upper flange was level), and drilled/clecoed the flange to the bottom of the fuselage. I started drilling the holes from the C/L & worked out in both directions.
9 Jan 2014 (1 hour, total time to date: 1094.0 hours)
Started work to mount the control stick. I cut/finished three 0.375 in. thick spacers for the control stick mounting bracket to fit in the web between the carry through spar caps. Then, I drilled #31 attachment pilot holes through the right side of the bracket & one of the spacers (vertically centered on the spacer).
10 Jan 2014 (2 hours, total time to date: 1096.0 hours)
I fabricated a jig to hold the spacers within the same vertical space as the BH73.75 web (between the spar carry thru caps). This will allow me to align the assembly in the jig, and make the installation much easier on the BH. I used the spacer I drilled yesterday as a drilling template for the center attachment of the bracket, then placed an un-drilled spacer in position and match drilled the attachment holes. For the left side, I MMD'd the attachment hole locations, & drilled the pilot holes through the bracket. Again, I replaced the last un-drilled spacer, and match drilled those attachment holes in the jig. I drilled all of these holes on my drill press to be sure that the holes through the spacers were as straight and true as possible. Finally, I started work laying out the control stick pivot mount on the bracket.
11 Jan 2014 (2.5 hours, total time to date: 1098.5 hours)
Finished aligning the pivot bracket on the mounting bracket. The pivot bracket came with #19 pilot holes, but the resulting edge margins are a bit thin for 3/16 bolts. I'll give this more thought later. I clamped the pivot bracket in place & match drilled the #19 holes through the mounting bracket. I then removed the pivot bracket, replaced the spacers, drilled the mounting bracket/spacer pilot holes out to #30, used -4 rivets to hold the spacers in place (not bucked, of course), & positioned the mounting bracket on BH73.75. The nice thing here was the spacers were already holding the bracket in alignment vertically (thanks to the jig). All that was left was to align the assembly along the A/C C/L. After checking and re-checking many times, I match drilled (#30) the center upper & lower bracket attachment holes through the web of BH73.75. I used wing nut clecos to hold the bracket to the BH. I then drilled out the left & right bracket attachment holes. I used clecos and some long rivets to hold the assembly on the BH for the picture.
I then started work to install the flap handle on the seat support BH. Fortunately, the center of the seat support upper flange is level wrt the lateral axis, so I could use it as a reference. Since I located 3 tooling holes approx. 3-3/8 in. above the bottom of the BH, I clamped a straight piece of 1x2 level across the center of the holes along the A/C C/L, & marked a line across the BH. I then removed the BH & clamped it level (using the BH flange reference) to a piece of plywood that was attached vertically to my work table. I checked the reference line and made minor adjustments to be sure it was level & at the proper height about the bottom of the BH.
I then started work to install the flap handle on the seat support BH. Fortunately, the center of the seat support upper flange is level wrt the lateral axis, so I could use it as a reference. Since I located 3 tooling holes approx. 3-3/8 in. above the bottom of the BH, I clamped a straight piece of 1x2 level across the center of the holes along the A/C C/L, & marked a line across the BH. I then removed the BH & clamped it level (using the BH flange reference) to a piece of plywood that was attached vertically to my work table. I checked the reference line and made minor adjustments to be sure it was level & at the proper height about the bottom of the BH.
12 Jan 2014 (3 hours, total time to date: 1101.5 hours)
I removed the seat support BH from the plywood to check the level on the A/P one more time. I then returned it to the plywood stand & clamped the flap torque tube/handle in place with the stand-off mounts. I checked/re-checked the position/alignment of the assembly, then marked the outline of the attachment flanges (to be sure to have even/proper edge distances). I removed the torque tube & MMD'd the attachment pilot holes through the BH web. I replaced the torque tube/mounts, clamped them back in place, & match drilled the pilot holes through the aft side of the BH web. I decided to install 0.040 doublers on the aft side of the BH web at the attachment points to provide a little more support. I cut out the doublers, removed the torque tube again, removed the BH from the plywood, aligned/duct taped the doublers on the aft face of the BH web, & match drilled the pilot holes. I'll install rivets around the edges of the doublers, but will wait until I know exactly where the rudder cables will pass through. I made the doublers a little over sized to keep my options open.
13 Jan 2014 (1 hour, total time to date: 1102.5 hours)
I spent some more time looking at the path of the rudder cable from BH99.35 to the rudder control horn. I had noticed that the path under the rear spar carry through bottomed out on the cable pass-thru at BH177.5. I wanted to find out how much the holes need to be enlarged to accommodate the cable. In order for the cable to pass through the center of the pass-through, it must pass through the plane of BH99.35 six inches below the A/C C/L. The picture here was taken with the wire in that orientation. The center of the pass-thru on the fin spar is approx. 1 in. above the A/C C/L, the distance to BH99.35 is 82.65 in., and the pass-thru at BH177.5 is 0.75 in. above the C/L. Therefore, if the cable goes thru BH99.35 at a distance of 15.5 inches below the C/L (where the plans appear to place it), it will pass through BH177.5 at approx. 0.1 in. above the C/L. To provide some additional clearance, I would need to cut into the flange of the transverse BH. Another issue is the direct path from the rudder pedals also appears to interfere with the inside flange of BH160. If I am correct (I'll check this again tomorrow), 2 turns in each cable may be required. I need to make another call to Chris at MA.
14 Jan 2014 (1 hour, total time to date: 1103.5 hours)
While checking the rudder cable route, I saw that the bent rudder skin (flange) interferes with the cable connection as the rudder deflects. I removed the rudder and trimmed/finished the area around the cable connection. I decided to attach the cable since the rudder was removed so that I could check the route with the cables. The cable connectors will not fit through the pass thru holes (close, but not quite) in the fin spar, so I simply ran the cables through the holes from the rear. The holes in the spar are already very close to the edge, so it makes no sense to touch those holes and weaken the spar.Anyway, after re-mounting the rudder, the cables fit nicely, and the rudder swings freely. However, it is clear that the direct path to the rudder pedals results in the cable touching the inside edge of BH160. I'll put this on hold for now - time for more thought before cutting anything.
15 Jan 2014 (1 hour, total time to date: 1104.5 hours)
I laid out the elevator push rods to locate the approximate location of the bellcrank in the tail cone. I want to locate the hole required through the lower web at BH99.35. It looks like the bellcrank sits approx. 10 in. aft of the BH. I cut a 1.25 in. wide x 3.5 in. deep notch in a straight piece of 1x6 so that I could lay it between the control stick & the location of the bellcrank to find the vertical location of the hole on the BH. The vertical swing of the rod appears to be approx. 3/8 in. (I'll call it 1/2). I didn't drill the hole - want to sleep on it. I also did some preliminary checking on the location of the hole in the fuselage skin for the aileron push rods. This is a bit more difficult because of the wing dihedral. The M1 update drawings show the rod to be centered on the rib at station 73.5. This will take more time to work out but I wanted to take a look at it now. Also, I talked to Chris today about the rudder cable path. He told me that he would do some research and get back with me tomorrow.
16 Jan 2014 (0.5 hour, total time to date: 1105.0 hours)
I didn't hear back from Chris today, so I did a little more work on the elevator bellcrank. There are no instructions on the assembly of the bellcrank, and a mounting bracket is not included in the fuselage kit. I pulled out the bellcrank parts and familiarized myself with them. It doesn't look difficult, but I will have to come up with a design for the mounting bracket. I also laid out the C/L along the inside of the bottom skin of the tail cone.
17 Jan 2014 (1 hour, total time to date: 1106.0 hours)
I took more measurements to help me design the elevator bellcrank mounting bracket. I found a couple of helpful examples of mounting brackets on-line, but I need to verify the amount of space required as well as how the push rod fits. In addition to taking measurements inside the tail cone, I measured the location of the elevator control horn attachment point. I also slipped the push rod inserts on one end of the rod and inserted the rod inside the tail cone with the tapered end of the insert through the pass-thru in BH177.5. After running the numbers based on the measurements (and the test fit), I found the following: 1) The position of the bellcrank between 4 and 10 inches aft of BH99.35 makes little difference in the alignment of the push rod to the control horn (this is because of the slope of the tail cone skin) 2) I will need to add an extension to the push rod insert to reach the elevator control horn 3) If I assume 0.5 in. clearance between the bottom of the control horn and the tail cone skin, I will need to trim the pass thru hole in BH177.5 approx. 0.25 in. lower. The benefit of moving the bellcrank a few inches forward is to provide additional margin for the elevator push rod under the seat and will allow additional tubing material (cut from the tube between the control stick and the bell crank) to be used as the extension required to reach the elevator control horn. I will need approx. 2.75 in. of extension to reach the control horn and allow 1+ in. for and aft travel (1 in. travel of the push rod results in approx. 20 degrees of elevator deflection). I also took a measurement of the vertical distance of the rudder pedal cable attachment to the A/C C/L (approx. 11.9 in. below). It looks like the vertical path to the bottom of BH99.35 will pass nicely through the lower portion of the web of BH73.75 & under the flap torque tube.
18 Jan 2014 (2 hours, total time to date: 1108.0 hours)
I came up with a design, drew the template for the bellcrank sides, cut blanks out of some 0.032 sheet to use as a prototype. I used my bending brake to bend the bottom edge, then cut hard plywood bending forms to finish the prototype. I think it will work well, but I need to make a couple of minor adjustments to the bend lines to get the push rod where I want it. I'll try it out on some 0.040 sheet tomorrow.
19 Jan 2014 (2 hours, total time to date: 1110.0 hours)
I reduced the height of the sides slightly by moving the upper end of the tabs down the bend line approx. 0.2 in. I cut out the 2, 0.04 thick blanks & bent the bottom flanges in my bending brake. I cut/finished the tops of the forming blocks to match the new height and made the other bends in each part. Finally, I spent a little time cleaning up the edges of the parts. There is more trimming to do, but it will depend on the final fit.
20 Jan 2014 (2 hours, total time to date: 1112.0 hours)
I cut two pieces of 0.062 angle (1x1) to just over 7 inches to fit along the bottom of the bellcrank housing. They will serve as the base to attach the housing to the bottom skin of the tail cone. I also plan to fit a 0.032 doubler to the skin in that area to locally strengthen the skin. I MMD #41 pilot attachment holes on each leg of the angles. I centered the holes on the bottom leg, applied an edge distance of 12/32 along the vertical leg, and used a hole spacing of 1.25 in. I then started work to assemble the housing. The distance between the vertical attachment tabs is approx. 1.625 in. - based on the bellcrank dimensions and the lengths of the bushings provided by MA. I laid out the assembly to check the fit using 2 pieces of finished 1x2s with 2, 0.032 shims on each side. I made some slight adjustments to the bend angles and bottom edges of the sides so that the tabs were vertically aligned. Finally, I sanded the faces of the 1x2s to give me a little less than the 1.625 in. thickness with the shims and glued the pieces together (the bond line will add some thickness back).
21 Jan 2014 (1 hour, total time to date: 1113.0 hours)
I did a little finishing work on the 2x2 that I glued together yesterday. I will use it as a spacer between the sides & to check the alignment of the bellcrank housing. I will also use it to align the bellcrank bolt holes (I want to have 0.5+ in. clearance for the lower push rod bearing). After checking the location of the bellcrank bolt & vertical alignment of the left side on the 1x1 angle, I match-drilled the attachment pilot holes between the angle and the side.
22 Jan 2014 (1 hour, total time to date: 1114.0 hours)
Checked the alignment of the right side of the bellcrank housing on its base angle and match drilled the attachment holes. I also cut a piece of 0.032 sheet as the base for the housing and laid out the C/L and the outside edge of the angles.
23 Jan 2014 (1 hour, total time to date: 1115.0 hours)
While preparing to mount the sides of the elevator bellcrank housing to the base, I noticed that the outside faces of the 2x2 were not parallel. I fixed that problem with my disk sander, and added the necessary shims to maintain the spacing of 1.625. I then aligned & drilled the pilot attachment holes between the side angles and the base.
24 Jan 2014 (1 hour, total time to date: 1116.0 hours)
I MMD'd a #40 pilot hole through the 2x2 spacer at the location of the elevator bellcrank pivot. I used 3.875 in. from the base of the housing to allow 0.5 in. clearance for the push rod bearing. I then epoxied 2, 0.032 thick shims on one side of the spacer (I'll drill through one side at a time now that I have a straight, centered hole in the spacer). Also, I trimmed/finished the edges of the upper "ears" of the housing. Finally, I took a more critical look at the housing, and I have the sides slightly staggered - approx. 0.05 in.. The variation in the bends make it difficult to get the alignment perfect, but it just didn't look quite right to me. I'll fabricate a new base tomorrow and see if I can get this right. :-)
25 Jan 2014 (2 hours, total time to date: 1118.0 hours)
I epoxied the shims on the other side of the 2x2 wood spacer. Then, I fabricated a new 0.032 base for the housing, match drilled the right side, and MMD'd the new attachment holes on the left side (much better now). Finally, I cut out a cardboard template to fabricate doublers for the upper portion of the housing.
26 Jan 2014 (3 hours, total time to date: 1121.0 hours)
I drilled through the shims on the left side of the spacer (used duct tape to get the thickness up to 1.625 in.), and started work on the housing doublers. I cut out the blanks, drilled 0.25 in. holes for stress relief at the inside corners, cleaned up the edges, and bent the doublers to fit on the housing. I then laid out the locations of the fasteners, drilled the pilot holes, clamped them in place, & match drilled the pilot holes through the sides.
27 Jan 2014 (1 hour, total time to date: 1122.0 hours)
I started work to fabricate my own elevator bellcrank. I'm sure the one provided in the kit is perfectly safe, but I just want a slightly "beefier" version. From everything I've read and my experience riding in a MII, I know the stick forces are quite low. I doubt I'll ever pull more than 20 lbs (if that), but I like knowing that it will be strong enough for 50 lbs at the stick. I cut out two 0.09 thick blanks, lightly finished the edges, and match drilled the center and rod bearing pilot holes.
I'll have a few days off, but hope to be back at it on Friday......
I'll have a few days off, but hope to be back at it on Friday......
30 Jan 2014 (1 hour, total time to date: 1123.0 hours)
Well. I was able to get back to work a day earlier than expected. I match drilled the center holes in the bellcrank sides to 1/8, then drilled the center hole in the right side out to 0.25 to accommodate the centering pin of my 0.875 hole cutter. I cut the 0.875 hole in the right side for the bell crank bearing hub and de-burred the hole. Finally, I drilled the 12 pilot attachment holes for the bellcrank bearing. I know I don't need all 12 (the kit bellcrank uses 6), but my new parts allow for more edge distance, and the holes are pre-drilled in the bearing, so I may as well fill them.
31 Jan 2014 (3 hours, total time to date: 1126.0 hours)
After taking another look at my estimated load on the bellcrank, I decided to fabricate another one. Again, I know my estimate is very, very high (50 lbs ult. at the stick), but I want to be consistent. Based on what I can see on-line, the actual stick force will be on the order of 10 lbs (max), and if you assume 20 lbs as the ultimate, the kit part is absolutely fine. This is clearly demonstrated by several flying Midgets. I simply want a little extra "cushion," and the extra weight is negligible. Also, the bearing is attached on one side, so the actual loads are more difficult to estimate (I simply made the conservative assumption that all of the longitudinal bending load is carried by that side). As a result, I also decided to return to the use of 6 rivets at the bearing attachment to increase the net area at the ligament on each side of the bearing housing. The mechanical advantage at the stick is approx. 5:1, so 50 lbs at the stick is 250 lbs at the push rod attachments and approx. +/-550 lbs across the ligaments on either side of the bearing hub. The stress distribution will be non-linear because of the hole, but the Kt effect is mitigated by the linear reduction in load from the outside edge (due to bending). The net Kt is approx. 2.2 (Peterson using width of 2 at the hub and a 0.875 bearing cut-out), so a net section stress of 15 ksi would leave an additional safety factor of approx. 1.5 for the ultimate load. Short of running a test, I believe this is more than adequate to account for the unknown effect of the filled bearing attachment rivet holes. See why structures guys shouldn't design airplanes :-) Anyway, I fabricated the new right side bellcrank using 0.125 thick sheet, and a new left side using 0.09 thick sheet. I drilled the bearing hub attachment holes to 1/8 (will clean them out to #30 later), and cut a 0.5 inch hole in the left side with a 0.625 "step" on the outside to accommodate a nylon shorty bushing.
1 Feb 2014 (3 hours, total time to date: 1129.0 hours)
I did a little more finishing work around the ends of the bellcrank and started working on new spacers. The space between the sides of the bellcrank is 0.44 in. to accommodate the push rod bearings. I don't have any 0.44 thick material (or a milling machine), so I cut a piece of 0.5 in. thick 6061-T6 and used my disk sander to take it down to 0.45 (I left some room in case I decide to use teflon tape to isolate the aluminum from the steel rod bearing). It was a slow process because I was being careful to keep the thickness as uniform as possible by continuously checking the dimensions with a caliper. I drew lines across the surface with a sharpy marker, ran a few passes on the sander, looked at the surface to see where the marks were removed, and adjusted accordingly. Mostly, I needed to turn the piece over since I tended to take more off of the bottom half of the piece. It also got too hot to hold pretty quickly, so it was a stop and go situation. I carefully finished the surfaces with a finer sanding disk and scotch brite using my angle die grinder. Once that was done, cut the the 2 spacers out of the piece approx. 1.65 x 1.25 each, tapered them to fit nicely inside the bellcrank, and laid out a 4 rivet attachment pattern. This is also larger than the spacers in the kit, but I've never tried riveting through this much material. I'm a little concerned about how the -4 rivets will expand properly through the entire thickness (I'll test this before I do it), and I feel better with 4 rivets rather than 2. I will probably add a lightening hole in the center of the pattern since the spacer itself takes no real load. Finally, I drilled out the 4 pilot (#31) attachment holes in each spacer.
2 Feb 2014 (3 hours, total time to date: 1132.0 hours)
I used some scrap material to see how well the back riveting method works on a thicker stack (0.5 thick sandwiched between 2, 0.090 sheets). I riveted 3 holes, then drilled off the heads (AD470-4's) and sanded down the surfaces to see how well the holes were filled. I set the rivet on the right first and noticed that the shop head diameter was relatively small when set at the proper height. For the second (on the left), I cut the rivet a little long (~1.75D), but had trouble keeping it straight (no surprise). Also, the tail of this one came off very easily. Then, I drove the one in the middle a little deeper - just to see what effect it would have on the fill. Well, the results were pretty clear. The heads were not filled (lower left), although the sheets seem to be securely attached. The shop head side was fine (lower right), but this is not good, so I will not use this procedure for the bellcrank. I believe that this stack is simply to large for back riveting.
Also, I MMD'd a 0.125 pilot hole in the center of the fastener pattern in each bellcrank spacer for a 0.5 in. lightening hole. Finally, I trimmed the top of the bellcrank housing doublers to level them, and marked the location of the 2x2 spacer in preparation for drilling out the pilot hole for the bellcrank pivot bolt.
Also, I MMD'd a 0.125 pilot hole in the center of the fastener pattern in each bellcrank spacer for a 0.5 in. lightening hole. Finally, I trimmed the top of the bellcrank housing doublers to level them, and marked the location of the 2x2 spacer in preparation for drilling out the pilot hole for the bellcrank pivot bolt.
3 Feb 2014 (1 hour, total time to date: 1133.0 hours)
Re-checked the alignment/position of the 2x2 wooden spacer & marked it's location on the base & left side of the bellcrank housing. I removed the right side of the housing, clamped the spacer in place on the left side of the housing, & drilled the 0.125 pilot hole through the pivot bolt hole in the spacer. Then, I replaced the right side of the housing, clamped the upper portion of the housing in place, & drilled the pilot hole through the right side of the housing. This allowed me to use the hole in the spacer as a drilling guide to align the pivot bolt hole in the bellcrank housing. I then enlarged the hole to #29 to accommodate a #6 machine screw to temporarily hold the upper portion of the housing to the spacer. Finally, I MMD'd 4, #41 pilot holes around the pivot bolt hole on the right housing doubler. I will be adding another 0.040 doubler on the outside of the upper portion of the housing with a horizontal flange for additional stability. I used a spacing of 1.25 in. and a pitch of approx. 0.625+ (to maintain edge margins) for -4 rivets that will hold the doublers around the pivot bolt.
4 Feb 2014 (1.5 hours, total time to date: 1134.5 hours)
I cut two 0.040 thick blanks to serve as an additional doubler on each side around the bellcrank pivot bolt and cut hard wood forming blocks to bend the upper flanges of the housing side doublers. Then, I marked the location of the bend lines in the side doublers, removed them, bent them using a plastic mallet, and finished the bends with a flanging tool. I replaced the side doublers, marked the front/rear flanges for trimming, and bent the flanges in the second doubler in my bending brake.
5 Feb 2014 (1.5 hours, total time to date: 1136.0 hours)
I couldn't find a #6 machine screw long enough (2+in.) to temporarily hold the upper portion of the housing in place, so I opted for #8. I lined up the holes through the 2x2 spacer, clamped the sides, and drilled the pivot bolt hole out to #21. I then installed the temporary machine screw with a wing nut. I laid out some RAM BOARD to make templates for the front & back covers for the housing. This works very well since it is very easy to fold and verify the required bend line. I marked and cut the cover pieces from 0.040 sheet, lightly finished the edges, marked the bend lines, and made the necessary 45 degree bends in my brake.
6 Feb 2014 (1 hour, total time to date: 1137.0 hours)
I trimmed/finished the edges of the front cover flush with the sides of the housing, clamped it in place, and laid out the attachment hole locations. Then, removed the cover & drilled the #41 pilot holes in the cover, replaced the cover on the housing, & match drilled the pilot holes through the front housing flanges. Finally, I started work trimming the back cover.
7 Feb 2014 (1.5 hours, total time to date: 1138.5 hours)
Finished trimming/finishing the back cover. I will be using nut plates to secure the back since it must be removed to install/remove the bellcrank and forward push rod. Laid out the fastener locations, drilled the pilot holes in the cover, replaced it, & match drilled the holes in the rear flanges. Then, I removed the right side doubler & match drilled the attachment and pivot bolt holes in the upper right side doubler (tripler around the pivot bolt). Finally, I removed the left side doubler, marked the "tripler" attachment holes, drilled these pilot holes, match drilled the holes through the tripler, and re-assembled the housing.
So far, so good with my housing design .....
So far, so good with my housing design .....
8 Feb 2014 (3 hours, total time to date: 1141.5 hours)
I took the elevator bellcrank housing apart & trimmed/finished the areas of the flanges that had marked earlier. I used a 1/4 in. Dremel sanding drum to smooth the transitions at the corners. I also match drilled the tripler attachment holes around the pivot hole through the left and right main sides. While I had things apart, I took a little more time to finish the edges of all of the parts. After more thought about the thickness of the right side of my bellcrank, I convinced myself that I was being far to conservative. I fabricated a new right side from a piece of 0.09 sheet, but maintained the 2 in. width at the hub. To ensure that the hub lined up with the Shorty bearing I plan to use on the left side, I cut/finished a 0.5 washer with a 0.125 center hole (using my 0.75 in. hole cutter). I placed the washer in the center hole on the left side and used it as a template for the new right side. Now, I'm more confident that these will line up properly. I then progressively drilled out the center hole on the new right side to 0.25 in. to accommodate the centering pin for my 0.875 in. hole cutter, and cut the hole for the bellcrank bearing. Finally, I used the old bellcrank as a template to match drill the 6, 0.125 pilot holes for the bearing attachment.
9 Feb 2014 (3 hours, total time to date: 1144.5 hours)
Located the spacers on the elevator bellcrank. I placed them 20/32 from the center of the push rod attachment holes to allow clearance for the rods with approx. 25+ degrees of rotation. I can get a little more clearance (shouldn't need it) by rounding the corners of the spacers). I clamped the spacers on the right side of the bellcrank & match drilled the 1/8 in. pilot attachment holes and the center lightening holes. I drilled #40 holes in the center of the spacers originally provided by MA & the ends of the bellcrank sides, and used them to align the ends of the bellcrank using long -3 rivets. Once aligned with the spacers, I match drilled the spacer holes through the left side. I polished a few long -4 rivets (using my scotch brite wheel) to fit in the 1/8 in. holes to hold the spacers in place while I match drilled the holes. I then copied the fastener pattern on a scrap piece of 0.040 & cut a 0.5 in. lightening hole (to take a look at it). I decided to cut the 0.5 hole in the spacers, but reduce it to 7/16 on the bellcrank (just to provide a little more strength). I want holes in the bellcrank to prevent moisture from collecting inside the spacer cut-out. I mounted the spacers on a piece of plywood by match drilling 1/8 holes through the attachment holes & inserting long -4 reduced rivets in the holes. I cut the lightening holes in the spacers, then cut the holes in the bellcrank sides. I checked the weight savings for the spacers, and it wasn't much - 4-5 grams each. However, it's still weight that is not needed. Finally, I fabricated another coupon to test the hole fill for long -4 rivets through 0.5 in. thick aluminum sandwiched between 2 pieces of 0.090 sheets. I drilled 3 holes as I did previously for the back rivet test.
10 Feb 2014 (1.5 hours, total time to date: 1146.0 hours)
I came up with an idea that may allow me to rivet the test coupon without an extra set of hands. I fabricated a small (12x2.25) shelf that I can clamp on the side of my work table from some scrap 1/2 in. plywood. I can lay coupon on it's side with a bucking bar behind it (I'll add a picture when I try it). Then, I started work opening up the rivet holes in the elevator bellcrank to #30. Hopefully, I'll get a warmer day soon so I can get some ventilation to alodine the parts. To keep the hub holes on each side aligned, I clecoed the push rod attachment holes together (these were the original holes used to align the parts), & drilled out the spacer attachment holes to #30. I then used long rivets to hole the parts in position, clamped them together, & drilled out the push rod holes to #30. I then drilled the holes in the smaller spacers to #30, replaced them between the push rod holes, replaced the new spacers, inserted long rivets through the push rod holes, used my reduced rivets to hold the spacers in place, clamped the parts together, & match drilled the spacer attachment holes out to #30. Finally, I started drilling out the rivet holes in the bellcrank housing out to #30.
11 Feb 2014 (1 hour, total time to date: 1147.0 hours)
I drilled out the attachment holes on the back side of the bellcrank housing to #21 in preparation to install #8 nut plates. I want the holes tight since I'll be match drilling the nut plate attachment holes using a nut plate as a drilling template. I match drilled the holes around the pivot bolt into the spacer to allow me to insert -3 rivets to hold the "triplers" in position while I drilled out the pivot bolt hole to 3/16. Then, I match drilled the bellcrank bearing attachment holes through the right side and the bearing t0 #30. Finally, I diss-assembled the bellcrank housing and started progressively match drilling the attachment holes on the right side out to #30.
12 Feb 2014 (1 hour, total time to date: 1148.0 hours)
Finished drilling out the holes on the right side & did the same on the left. I then cut a 7/8 in. clearance hole for the push rod in the front cover & trimmed the sides with my Dremel. I re-assembled the housing for the picture.
Finally, I clamped the small shelf to one of my sturdy work tables, cut 3 rivets to length, & tried out my idea to rivet the test coupon by myself. It seemed to work well, but I'll drilled the heads/tails tomorrow and see how it looks.
Finally, I clamped the small shelf to one of my sturdy work tables, cut 3 rivets to length, & tried out my idea to rivet the test coupon by myself. It seemed to work well, but I'll drilled the heads/tails tomorrow and see how it looks.
13 Feb 2014 (0.5 hour, total time to date: 1148.5 hours)
I drilled the heads off of the test specimen, sanded off the tails, & finished the surfaces to take a look at the hole fill using the standard "front" riveting process. This time, the holes appear to be completely filled on both sides. To me, the lesson learned is not to back rivet thick stacks. I also believe that the indicator of a bad back rivet is the noticably smaller diameter of the shop head.
14 Feb 2014 (2 hours, total time to date: 1150.5 hours)
I went back to work on the elevator bellcrank housing. I made the final pass through the -4 rivet attach holes with a sharp #30 bit. I know my progressive drilling preference takes time, but I think it results in better hole quality. I took the housing apart, and cut out 2, 0.050 steel blanks to fit inside the housing around the pivot bolt. They will serve as very large "washers" for the pivot bolt bushings, provide more bearing support, and will be permanently attached by the 4 rivets around the pivot bolt. It would have been very, very difficult to install standard washers in the assembly since the space is tight, and the bushings will be enough trouble to hold in place while installing the pivot bolt. I finished the edges of the steel blanks, marked the center for the pivot bolt hole, clamped each plate to the upper tripler (easier to use it as a drilling template for the blanks), and match drilled 1/8 pilot holes for the 4 attachment rivets. Then, I clecoed the steel to the tripler and match drilled the 3/16 pilot pivot bolt holes. Finally, I assembled the housing sides, used a short AN3 bolt to hold the steel "washer" in place with 2 clecos in diagonal rivet holes, and matched drilled the rivet holes out to #30 (through the steel side). I took everything apart and started de-burring the holes.
15 Feb 2014 (1.5 hours, total time to date: 1152.0 hours)
I drilled the #8 nut plate attachment holes in the flanges of the side doublers for the rear bellcrank housing cover plate. I then removed the protective plastic from the parts, de-burred the holes, and finished the edges in preparation for etch & alodine.
16 Feb 2014 (3 hours, total time to date: 1155.0 hours)
Assembled the sides with the steel inserts & progressively match drilled the pivot bolt holes out to 0.25 in. Took everything apart again & went over all of the holes/edges to be sure that they were ready for etch/alodine/prime. Cleaned the parts with my PPG de-greaser, and shot a light coat of lycoming grey on the steel parts. I etched/alodined the aluminum parts, let them dry, then applied a light coat of primer on the mating surfaces. Of course, this was done in stages since some parts had mating surfaces on either side.
17 Feb 2014 (3 hours, total time to date: 1158.0 hours)
Riveted the bellcrank bearing to the right side of my elevator bellcrank and started work assembling the housing. I riveted the #8 nut plates to the rear flanges of the left and right sides of the housing. Then, I riveted the left & right side doublers together. in order to be sure that the upper pivot bolt area was in alignment, I clecoed the pieces in place & inserted an AN4 bolt in the pivot hole (it was a nice, snug fit). Finally, I installed the rivets around the pivot bolt holes on each side.
18 Feb 2014 (2 hours, total time to date: 1160.0 hours)
I riveted the base 0.062 1x1 angles to the left & right sides of the housing. I realized that I had neglected to prime the inside of the front panel, so I de-greased & primed it. Finally, I cut several rivets to length for the bellcrank assembly.
19 Feb 2014 (1 hours, total time to date: 1161.0 hours)
I riveted the front cover on the housing to complete the housing assembly. Now, I need to finish the bellcrank and start fitting the push rods.
20 Feb 2014 (1 hour, total time to date: 1162.0 hours)
Riveted the bellcrank sides together (4 rivets around each spacer) using the same method that I used on the thick specimen on 12 Feb.
21 Feb 2014 (1 hour, total time to date: 1163.0 hours)
Re-checked & adjusted the C/L aft of BH99.35. Marked the vertical C/L on the lower web of BH99.35. I ran the numbers to estimate the location of the push rod pass-thru at BH99.35. If I place the center of the bellcrank 5.75 inches aft of BH99.35, the center of the push rod should pass through the BH 1.25 in. above the bottom skin at the lowest point. As the push rod moves 1 inch forward and aft, the rod will move up approx. 0.375 in. I located these two points on the vertical C/L of BH99.35, clamped a scrap piece of plywood on the back of the BH, drilled the two 1/8 in. pilot holes, then cut the 0.75 in. pass thru holes. Then, I used a drum sander to clean up the edges of the oval cut-out.
22 Feb 2014 (2 hours, total time to date: 1165.0 hours)
I decided to drill out the holes for the control stick mounting bracket to 3/16 & install An3's to replace the clecos that had been temporarily holding it in place. Then, I started work to fit the elevator push rod between the control stick and the elevator bellcrank housing. I've had a few comments about the housing being pretty "beefy" (and I've said the same myself). However, I checked the weight without the 1/4 inch pivot bolt (12.5 oz.). For comparison, two 1x1x0.062 angles running between the BHs weigh in at 11.6 oz. Adding the sides, you come out a little heavier than my housing, but only by a couple of ounces. However, my little brick sh*t house has tremendous lateral stability. I've still got to add the base reinforcement to the skin, so it's about even in terms of total weight.
I had a bit of a scare when I connected the push rod to the bellcrank. The shoulder of the rod bearing was interfering with the sides of the bellcrank as it rotated. Also, I noticed that the alignment was off. It turned out that the bearing had seized up at a slight angle. However, this brought up another issue. The kit supplied bellcrank spacers were 0.44 in. thick (which just clears the thickness of the -5 rod bearing (no room for washers). When the bellcrank rotates past the "shoulder" of the bearing, there is no allowance for any mis-allignment - defeats the purpose of the swivel bearing. So.....it looks like somebody will be making another bellcrank with 0.5 thick spacers to allow for thin washers, and I'm guessing that somebody will be me ;-). Practice makes perfect...... However, for now, I'll move ahead with the fitting work.
I had a bit of a scare when I connected the push rod to the bellcrank. The shoulder of the rod bearing was interfering with the sides of the bellcrank as it rotated. Also, I noticed that the alignment was off. It turned out that the bearing had seized up at a slight angle. However, this brought up another issue. The kit supplied bellcrank spacers were 0.44 in. thick (which just clears the thickness of the -5 rod bearing (no room for washers). When the bellcrank rotates past the "shoulder" of the bearing, there is no allowance for any mis-allignment - defeats the purpose of the swivel bearing. So.....it looks like somebody will be making another bellcrank with 0.5 thick spacers to allow for thin washers, and I'm guessing that somebody will be me ;-). Practice makes perfect...... However, for now, I'll move ahead with the fitting work.
23 Feb 2014 (4 hours, total time to date: 1169.0 hours)
I did a lot of "tinkering" today. The control stick mounting bracket needed a 0.032 shim along the center to sit flush against the spacer. Without it, the yokes on either side of the control stick mount will bind enough to add resistance to fore-aft stick movement because of the bending. So, I removed the bracket, cleaned up the new holes, fabricated a 0.032 shim, and re-installed the bracket. Then, I installed the control stick so I could look at the total range of motion and make adjustments to the push rod length and location of the bellcrank housing. I have resigned myself to the fact that I will not be using the powder coated push rod provided by MA because I would rather weld the rod ends, and I can use the one I have to play with the length. My goal was to locate the center of the housing between 5.5 & 7.5 inches aft of BH99.35. Close enough to be easy to reach behind the seat, but far enough to provide clearance for the fiberglass seat back. Right now, I plan to hang a canvas (or similar) pouch behind the top of the seat that can be secured at 4 corners for storage. For safety, I want to build a cover around the bellcrank so that nothing can fall and jam the bellcrank. With the housing close to the seat, I can mount the protective cover to the back of the seat. That way, it will come off with the seat back for maintenance. I adjusted the housing to be approx. 1.75+ in. clear of the seat back (it extends back 3 in. from the canted web of BH99.35). After adjusting the push rod to give +/- 1.125 movement foe and aft from neutral, I found that I had cut the rod a little short (again, good thing I planned to used it as a practice piece), but I had enough adjustment in the rod ends to get the adjustment. Then, I laid out the larger aluminum tube that extends back to the rear BH. There are 2 adapters for each end to attach rod bearings. The only problem is that this won't work at the elevator. The 0.75 pass through hole in BH177.5 is approx. 2 inches from the neutral point for the elevator control horn. Adding another 1+ inches for rearward travel, and it is obvious that I'm going to need an extension. Also, I want the jam nut on the extension to the rear adapter to remain in the tail cone so it can never snag the edge of the pass through hole. Therefore, I cut/finished the aluminum tube to the proper length, and temporarily installed a long AN6 bolt in the adapter to rest inside the hole. Before sliding the adapters in the tube, I applied a little WD40 and gun oil so I can get them back out later. BTW, the sitck movement is silky smooth :-).
24 Feb 2014
No building hours today. I needed more thinking time...... I had assumed that I could run 1x1x0.040 angles under the base of the housing on each side and extend it between the BHs to shear the bending load into the BHs. Well, I was wrong and should have checked the numbers more carefully - especially for the decks on either side. Not a big problem, but I need to change a few things with the housing as well. I realized that I should be able to remove it in case I ever need to crawl back into the tail cone. I called my good friend, Tom, and asked for his input on some alternatives. I'm finalizing a plan right now. This is a great example of why it's always a good idea to hold off on cutting metal until you have checked and re-checked.
25 Feb 2014 (1 hour, total time to date: 1170.0 hours)
I laid out the location for the push rod cut-out in the seat BH. I drilled the pilot holes, cut the 0.75 holes, and trimmed/finished the edges. I started work to run the rudder cables.
26 Feb 2014 (1 hour, total time to date: 1171.0 hours)
I need to locate the pass-thru holes for the rudder cables in BH73.75. I'd like to be very accurate (obviously), so I designed a tool to determine the pass-thru location. I started working on it today. I cut pieces of very straight oak 1x2s to length, and drilled holes along the length (50 in.) to adjust the span of the tool. I also drilled matching holes through the 3, 8 in. arms that will be attached along the span. These holes will align to locate the straight line at any point along the span.
27 Feb 2014 (1 hour, total time to date: 1172.0 hours)
I continued working on the tool to locate the pass through holes in BH73.75. I mounted the attachment brackets on the 2 outside legs & fit them to the spanwise member. I used steel T-brackets from Lowes, but needed to drill a 3/16 hole through the center between the existing screw holes for a single AN3 bolt to hold the brackets in place once I had them alligned properly. I used the screws supplied with the brackets to attach them, but the additional bolt was needed after final alignment to provide more stability.
28 Feb 2014 (1 hour, total time to date: 1173.0 hours)
I finished the hole locater. I used 2, 5 in. T-brackets to attach the sliding leg sandwiched between the spanwise member and another (7 in.) piece of oak 1x2. It seems to work well. I also cut the aft push rod tube a little shorter, because I needed to move the housing back a little further to give me a little more clearance with the recessed seat back. Now, I need to decide exactly where to locate the cable pass through in BH99.35. Not as easy as I thought because it will make a lot of difference as to what I can do with other structure. This is a great example of why it takes so much longer to make any design changes. In this case, I had no real choice since there are no instructions on how to run the cables, or for the bellcrank housing structure. Thanks to help from Tom, I've come up with a decent design for the beams running between BH99.35 and 128 to support the bellcrank housing and two decks on either side. The next step will be to build it and check to see how the cable will have to run.
1 Mar 2014 (2 hours, total time to date: 1175.0 hours)
I fabricated a small version of the tail cone Z-beam section to see if there were be any problems. There weren't any big problems with the bends, although I'll have to bend the top flange with long forming blocks (1x2s will do the trick). However, the bigger problem is that I don't have any 0.040 sheet long enough for the 28 in. run. I ordered more. In the mean time, I decided to start fabricating 0.05 thick steel pulley brackets for the rudder cables. I want to incorporate a cable bushing in the assembly to prevent the cable from coming off the pulley (especially when making adjustments with the tension off the cable). It took a few tries to get the bend where I wanted it in the bracket. I then drilled holes for the pulley and bushing, cut an axle bushing for the pulley, and assembled the parts. I checked to see how the bracket would fit on the lower web of BH99.35. I want to be sure to have the hole located so that the bracket will fit in the space available. I need to make some adjustment to the bracket to provide more hole spacing between the bracket attachments and the cable pass-through hole.
2 Mar 2014 (2 hours, total time to date: 1177.0 hours)
I spent some time putting the bending moment calculations in Excel for the tail cone beam. I wanted to look at various combinations of deck loading, g-levels, & stick force to be sure I'm covered. I'm not counting this as building time. Again, I'm sure my 50# stick force assumption is way too much, but even without it, I'd still need more beef to support much of anything behind the seat back.
I went back to work on the rudder cable pass-thru holes at BH99.35. I made a template of the bracket attachment with the pass-thru hole to make sure that I could get the bracket mounted under the rear spar carry-thru and have enough room to install the bolts. It looks like I will have about 1/4 in. under the spar, but will need to mount the bracket on the front side of the BH. It's a lot easier to install on the front anyway. I marked the template holes and the pass-thru holes 5 inches on each side of the C/L. I drilled a 1/8 in. pilot hole in a piece of 0.05 scrap steel to use as a drilling guide, duct taped it in place, and drilled the pilot holes through BH99.35. It was a relief to finally decide on the location and drill the darn holes! Then, I used my new hole locating doodad to mark the location of the pass-thru holes in BH73.75. Since the rudder pedal connection tab moves up and down, I marked the top and bottom of the travel. It's hard to see the marks on my black powder coated BH web, so I put some duct tape in the location and double checked the marks. I'll leave it here for now and check it one more time tomorrow before drilling these holes.
I went back to work on the rudder cable pass-thru holes at BH99.35. I made a template of the bracket attachment with the pass-thru hole to make sure that I could get the bracket mounted under the rear spar carry-thru and have enough room to install the bolts. It looks like I will have about 1/4 in. under the spar, but will need to mount the bracket on the front side of the BH. It's a lot easier to install on the front anyway. I marked the template holes and the pass-thru holes 5 inches on each side of the C/L. I drilled a 1/8 in. pilot hole in a piece of 0.05 scrap steel to use as a drilling guide, duct taped it in place, and drilled the pilot holes through BH99.35. It was a relief to finally decide on the location and drill the darn holes! Then, I used my new hole locating doodad to mark the location of the pass-thru holes in BH73.75. Since the rudder pedal connection tab moves up and down, I marked the top and bottom of the travel. It's hard to see the marks on my black powder coated BH web, so I put some duct tape in the location and double checked the marks. I'll leave it here for now and check it one more time tomorrow before drilling these holes.
3 Mar 2014 (1 hour, total time to date: 1178.0 hours)
I checked the hole locations one more time, taped a drilling guide in place, and drilled each 1/8 in. pilot hole for the rudder cables in BH73.75. Then, I attached a small spring on each rudder pedal cable attach tab and ran a wire through the BHs to check the height of the wires at the seat support BH. It looks like they will be close (but under, thankfully) to the flap control tube. I'll have to remove the push rod and re-install the seat BH to see how it looks.
4 Mar 2014 (2 hours, total time to date: 1180.0 hours)
I removed the push rods/bellcrank housing and installed the seat BH to check the location for the rudder cable pass-through holes in that BH. The cables will pass close (again, but under) the stand-off brackets for the flap control torque tube. It's difficult to estimate the amount of "droop" to expect in the cables, but the straight line is under the bracket. I then removed the BH, marked the measured locations of the pass-through holes, and drilled 1/8 in. pilot holes approx. 0.3+ inches below the mark. This will allow for 5/8 in. pass-through holes and some room for any needed adjustments to the location. Also, I'd like to keep the holes as far as possible from the bracket attachment holes. I am considering 0.05 steel doublers on the back side of the BH in this area to stiffen it up since there will be significant torque applied through the brackets as the flaps are used. Finally, I cut 5/8 inch pass-through holes using the pilot holes drilled yesterday. I ran the wires through the holes, and it looks like they may be slightly off-center. However, I will install the turnbuckles at the rudder pedals and check again to see if any other adjustments are needed.
5 Mar 2014 (1 hour, total time to date: 1181.0 hours)
I connected the rudder turnbuckle assembly to the rudder pedal control tab, tied a cord to the cable eye, and ran the cord through the holes in BH73.75 & 99.35 to verify the cable path. The cord passed through the lateral center of the left hole, and was approx. 3/32 in. to the left of center through the right hole. I can adjust this by moving the hole in BH99.35 to the right when I drill it out to final size. Then, I replaced the seat support BH and checked the location of the cable pass-through holes. The location appears to be correct. I then cut a doubler blank from 0.05 thick steel, but came to my senses when I held it in my hand and felt the weight. I can stiffen the seat BH web around the pass-through holes (because they are located at the flap control tube stand-offs) sufficiently with a 0.040 thick aluminum doubler on the back side with a vertical flange bent along the inside edge. I started work cutting out the doubler blanks.
6 Mar 2014 (1 hour, total time to date: 1182.0 hours)
Finished cutting out the doubler blanks, bent the flanges, & match drilled the pilot holes for the stand-off bolts & the cable pass-through holes. Then, I laid out the rivet pattern for the doublers and match drilled them through the BH. Finally, I re-installed the BH to check the pass-thru holes. Looks good, but the cables really come close to the brackets. I suppose close is a lot better than the alternative, and maybe the cables will "droop" a bit more than my nylon cord.
7 Mar 2014 (3 hours, total time to date: 1185.0 hours)
I clecoed the flanged doublers to the back of the seat BH & elongated the cable pass-through holes using the Dremel with a 0.5 in. drum sander. It looks like the minimum height needed to allow the swagged rudder cable around an AN111 bushing is approx. 0.7 in. I elongated these 0.625 in. holes to approx. 0.8 in. I am leaning heavily toward using this arrangement so I can connect/disconnect the cable at the turnbuckle with an AN3 bolt instead of the cable eye end that came with the kit turnbuckle assembly. If I use the bushing , I can probably get the swagged ends through the 0.5 holes in the rudder spar (with the bushing removed), but I can make the remaining pass-through holes large enough to accommodate the finished ends.
I drilled out the doubler rivet holes to 1/8 in., cleaned up all of the holes, and clecoed them back in place. I wanted to be very careful drilling out the flap control stand-off attachment holes since it is important to maintain proper alignment of the torque tube. They have to be drilled from the back, and there aren't a lot of options for holding them in place. I cut a piece of 2x4 to fit between the doublers and securely clamped the torque tube to hold the stand-offs against the BH. The 2x4 helps prevent the BH from bending so adequate clamping force can be applied (but not too much to bend the tube. I found that my Irwin clamps work very well for this purpose by "hooking" them around the tube. Then, it was a matter of removing one cleco at a time, drilling out the hole to the next size, installing the next larger cleco, and so on..... I stepped up from #40 to #30, #21, #19, 3/16, then #12 to finish the holes for the AN3's. During the process, I removed the clamps after moving up to the next cleco size to verify that the tube was not binding. Once finished, I checked the tube fit with the AN3's, and it seemed very good. I removed the bolts/tubes/doublers, and cleaned up the holes. Then, I bolted the doublers back on the BH & finished the rivet holes out to #30. I removed the doublers, de-burred the holes, & finished the edges of the doublers. Finally, I de-greased the mating surfaces of the doublers/BH, applied a thin coat of etching primer, and called it a night.
I drilled out the doubler rivet holes to 1/8 in., cleaned up all of the holes, and clecoed them back in place. I wanted to be very careful drilling out the flap control stand-off attachment holes since it is important to maintain proper alignment of the torque tube. They have to be drilled from the back, and there aren't a lot of options for holding them in place. I cut a piece of 2x4 to fit between the doublers and securely clamped the torque tube to hold the stand-offs against the BH. The 2x4 helps prevent the BH from bending so adequate clamping force can be applied (but not too much to bend the tube. I found that my Irwin clamps work very well for this purpose by "hooking" them around the tube. Then, it was a matter of removing one cleco at a time, drilling out the hole to the next size, installing the next larger cleco, and so on..... I stepped up from #40 to #30, #21, #19, 3/16, then #12 to finish the holes for the AN3's. During the process, I removed the clamps after moving up to the next cleco size to verify that the tube was not binding. Once finished, I checked the tube fit with the AN3's, and it seemed very good. I removed the bolts/tubes/doublers, and cleaned up the holes. Then, I bolted the doublers back on the BH & finished the rivet holes out to #30. I removed the doublers, de-burred the holes, & finished the edges of the doublers. Finally, I de-greased the mating surfaces of the doublers/BH, applied a thin coat of etching primer, and called it a night.
8 Mar 2014 (2 hours, total time to date: 1187.0 hours)
Bolted the doublers on the seat BH & riveted them together using my squeezer with a 2.5 in. longeron yoke. I replaced the BH, cut a new forward push rod tube (I had cut the other one a little short), & replaced the bellcrank housing to check the fit and clearances. It looks like it would be better to move the housing aft another inch or so. I'll do a little more checking first, but it's a good thing I have plenty of 4130 tubing :-)
9 Mar 2014 (1 hours, total time to date: 1188.0 hours)
I cut a new push rod tube 2.5 inches longer than the previous one (easier to cut more off later), finished the ends, and inserted the rod ends. I will put it aside for now since it will be better to wait until I have the rest of the skin fitted and be able to remove the right side tail cone skin for better access inside the tail cone. I replaced the back of the bellcrank housing to keep the parts together. Finally, I removed the seat BH and elongated the push rod pass through for more clearance at the upper end. I drilled a 1/8 pilot hole in a scrap piece of 0.032 sheet, duct taped it in place on the BH web, & used my hole cutter to add more height to the pass-through. I finished the edges & put the BH aside for now as well.
10 Mar 2014 (1 hour, total time to date: 1189.0 hours)
I rounded the corners at the upper rudder pedal attachment holes for the connection to the brake cylinders. The sharp corners are of no structural significance, and rounding provides a little more clearance with the firewall. I then removed the center bottom skin & trimmed/finished the aft end between the rear spar and the splice stringer. I then replaced the bottom center skin. I should have done this from the start since it will allow a much better (flush) fit for the side skins. I'll simply extend the side skins down further to tie into the BH flange and the center skin.
It also looks like I should cut the corner (dog ear) the inside flanges of the steel support for the rear spar to give me a little more access to the fasteners at the corner of BH99.35.
It also looks like I should cut the corner (dog ear) the inside flanges of the steel support for the rear spar to give me a little more access to the fasteners at the corner of BH99.35.
11 Mar 2014 (1 hour, total time to date: 1190.0 hours)
I cut the inside corners off of the rear spar jig supports. I taped a scrap piece of 0.040 aluminum behind the support to protect the skins. I used a cut-off disk on my pneumatic die grinder. It took a lot longer than I expected - partly because of the awkward position and partly because the steel is pretty tough. This gives me better access to the skin in this area, but still will not allow me to buck a rivet on the flange of BH99.35 at the rear spar. However, I will be able to buck a rivet in the center bottom skin at this level as part of the side/bottom skin splice.
12 Mar 2014 (1 hour, total time to date: 1191.0 hours)
I "tack" riveted the bottom center skin to the splice stringer in preparation to fit the center side skins. I used 1097-3 rivets to hold the skin in place in approximately 8 locations on each side. I also used cargo straps to help hold the skin flush around the bottom corners, & inserted shims between the skin and the plywood support at BH73.75. This should help to prevent the skin from buckling when the forward skin is overlaid.
13 Mar 2014 (2 hours, total time to date: 1193.0 hours)
I re-checked the fastener locations along the upper longeron for the canopy seal strip, removed the strip, trimmed the ends, & drilled the pilot attachment holes. I replaced the strip & match drilled the attachment holes through the longeron. It looks like I will have to move the one of the holes on each side slightly as I drill them out to provide better clearance on the inside. Then, I measured & cut out a cardboard template for the center side skins. I taped it to the frame to check the initial fit and made some minor adjustments.
15 Mar 2014 (3 hours, total time to date: 1196.0 hours)
I traced the template pattern for the left side skin on a 2x4 ft 0.032 sheet and made the initial cuts with my pneumatic cut-off wheel. I finished the panel using a die grinder/disk sander & my Dremel tool/drum sanders. I clamped the skin in place along the longeron (checking the edge distance for the BH99.35 flange attachment hole in front of the rear spar). I also left a little overhang on top so I could finish the edge to be flush with the top of the longeron. I started match-drilling the pilot attachment holes along the longeron (starting in the middle and working outward). Then, I used a cargo strap to hold a 1x2 across the center section and worked my way down the skin on each side. I had to use a clamp between the 1x2 and the vertical web of BH73.75 to hold the skin flush against the flange because of the doubler along the side. I match-drilled the upper row of holes through the skin splice stringer (again from the center, working outward). I also drilled out a few of the holes in the splice in center of the lower row. Before I go any further, I will remove the skin & roll the lower extensions to match the curvature of the lower skin.
16 Mar 2014 (3 hours, total time to date: 1199.0 hours)
Removed the side skin & used my 4 in. PVC pipe "skin former" to add curvature to the lower extensions. It took one more test fit to get it to fit well. Then, I removed the skin, measured the edge distance of the lower row of fastener holes in the splice stringer to verify the spacing for the third row I would be drilling in the side skin (just below the stringer). I laid out the fastener location for the third row, and fabricated a drilling guide for this row. I taped the guide to the skin & match drilled the pilot holes in the skin. While the skin was off, I decided to drill pilot holes through the longeron at the flange of BH99.35. I had delayed this because I wanted to see how the skin would fit there because of the small gap between the longeron and the tail cone skin due to the longeron bend radius. It was fairly easy to pull the skin in tight without any significant local deformation. I also decided to drill the pilot attachment holes along the upper stringers and the longeron on the left side. To move the attachment hole, I will have to securely clamp a steel drilling guide to the longeron. I will have to remove the clecos in the area, so I want the longeron to be secured to the stringer to keep it from moving. I needed at least 8 rivets attaching the stringer to the longeron to match the load carried through the 8 rivets in the engine attachment bracket. I drilled 4 attachment holes along the top and 4 along the side of the longeron. Finally, I replaced the side skin & match drilled the lower row of pilot holes trough the bottom skin.
17 Mar 2014 (2 hours, total time to date: 1201.0 hours)
I inserted a wood shim between the left rear spar vertical support and the side skin to hold the skin against the BH99.35 flange & match drilled the pilot attachment hole at that location. Then, I removed the left side skin & set it aside. I used the side skin template to lay out the right skin pattern on another piece of 0.032 sheet, and cut out the right skin in the same manner as the left. I test fit the skin, made some minor adjustments, and finished the edges (also in the same manner as was done for the left side skin. Finally, I clamped the right skin in place and started match drilling the pilot attachment holes along the upper right longeron, working from the center outward.
18 Mar 2014 (1.5 hours, total time to date: 1202.5 hours)
I used 2 cargo straps on each side of the skin with a 1x2 to hold the skin against the BHs while I worked my way drilling out the pilot attachment holes along BH73.75 & 99.35. When I reached the skin splice, I started match drilling the pilot attachment holes through the splice stringer (working from the middle outward). Once this was complete, I removed the skin and started work laying out the 3rd row of pilot attachment holes in the skin.
19 Mar 2014 (1 hour, total time to date: 1203.5 hours)
I carefully checked the fastener hole layout for the third row of holes at the right side skin splice, taped the drilling guide in place, and match drilled the pilot holes in the skin. I used my PVC skin former to add the needed curvature to the extensions to the skin at BH99.35 & 73.75. I then replaced the skin & match drilled the pilot attachment holes along the 3rd row at the skin splice. As I did on the left side, I started in the middle of the skin and worked outward in each direction.
20 Mar 2014 (1.5 hours, total time to date: 1205.0 hours)
I used a wood shim to press the side skin against the BH99.35 flange at the right, rear spar & match drilled the pilot attachment hole at that location. I then finished match drilling the pilot attachment holes along the right longeron. There are two remaining pilot holes that have not yet been drilled on each side on the longerons. These are located at BH73.75 and 1 inch aft - because clecos are interfereing in this area. Since I still need to move two holes slightly aft on each longeron, I will wait until the longerons are removed for finishing & drill these holes out on my drill press. Finally, I laid out & drilled the 8 pilot attachment holes on the right side between the upper stringer and longeron as was done on the left side.
21 Mar 2014 (1 hour, total time to date: 1206.0 hours)
I MMD'd the #41 pilot attachment holes in the fuel tank support brackets. I've already made the decision that I'll be installing the top skin nut plates below the stringer, so I"ll be adding a doubler along the stringers. that will have to wrap around the brackets. I couldn't think of a better way to address the issue of the 0.062 bracket and the 0.032 skin that is supposed to fit over the top of the bracket and stringer. In addition to the potential problem fitting two rows of fasteners inside the channel (especially where the 0.125 thick longeron is nested inside). There is very little room for error and setting the rivets would be interesting.
I wanted to drill out the pilot holes in the brackets first, then match drill through the stringers. I carefully drilled the holes 1/32 under 0.5 in. spacing to allow a little margin for error when installing them on the stringers. The space inside the stringer channels will be tight, so I want to be sure to have adequate inside edge distance to set the rivets. My other concern was clearance for the AN3 bolt to attach the turnbuckle fitting once the skins are on. The channel sides and skin will be close, but it looks like it will work. It would seem nice to nest the bracket bend/channel radius, but this would require quite a bit of precision in the hole placement and would place the bolt head closer to the channel sides. The relatively small amount of bending from the applied load line shouldn't cause any problems - especially with the doubler installed.
I wanted to drill out the pilot holes in the brackets first, then match drill through the stringers. I carefully drilled the holes 1/32 under 0.5 in. spacing to allow a little margin for error when installing them on the stringers. The space inside the stringer channels will be tight, so I want to be sure to have adequate inside edge distance to set the rivets. My other concern was clearance for the AN3 bolt to attach the turnbuckle fitting once the skins are on. The channel sides and skin will be close, but it looks like it will work. It would seem nice to nest the bracket bend/channel radius, but this would require quite a bit of precision in the hole placement and would place the bolt head closer to the channel sides. The relatively small amount of bending from the applied load line shouldn't cause any problems - especially with the doubler installed.
22 Mar 2014 (2 hours, total time to date: 1208.0 hours)
I laid out/match drilled the pilot attachment holes for the forward fuel tank support brackets and drilled a pilot hole between the brackets and the firewall in the center of the stringer channel on both sides. I wanted to get these holes located as accurately as possible because they are very close to the engine attachment bracket rivets. Eventually, I'm going to have to get in there and set those rivets, so I want as much clearance as I can get. Then, I decided to use the remaining time to trim the edges of the side skins. Now that most of the attachment holes have been located in the center side skins, I can get them trim the edges to a good (a little generous) margin with a little room for final finishing later. I got most of the trimming done, but will need to get out the Dremel tool to work on the curved edges tomorrow.
23 Mar 2014 (3 hours, total time to date: 1211.0 hours)
Trimmed/finished the curved edges of the center side skins. I'll need to do a little more on the front and rear sides later, but I'd rather have more to remove than the other way around. The same goes for the top edge. The main thing was to get most of the excess material removed to check the fit and get ready to overlay the front skins. I replaced the skins and carefully drilled out the pilot attachment holes to #31. This allows me to switch to the larger clecos and frees the -3s for use on the forward skins, and I'll probably remove the skins a few more times so I'd rather keep the holes a little smaller. The holes along the BH73.75 flange remain #41 since I will be back drilling these out though the forward skin.
24 Mar 2014 ( 2 hours, total time to date: 1213.0 hours)
I removed the center side skins to clean out aluminum debris from the match drilling work done yesterday. I decided to drill out the holes to 1/8 since the cleco fit was really too tight (especially at the upper longeron .125 thickness). I drilled the holes in the longeron, replaced the skins & match drilled the holes from the inside. I then opened up the rest of the hole (again, except the holes along the flange of BH73.75). I removed the skins (again), lightly de-burred the holes, & did a little more trimming of the edges of the skins (while I was at it). I removed the remaining strip of plastic along the tail cone side skins at BH99.35 9 under the center side skins, and replaced the skins. Now, I can start work to fit the forward side skins.
25 Mar 2014 (1 hour, total time to date: 1214.0 hours)
Started work fitting 2 inch wide 0.040 doubler strips along the forward, upper stringers. The doublers will help to smooth the forward side skin attachment transition over the the 0.062 thick fuel tank support brackets, the firewall attach strip, and provide more support for nut plates used to secure the upper skin. As I wrote earlier, I think the space inside the stringer channel is too tight to install 2 rows of fasteners which would result in close edge margins for the upper skin attachment holes with very little room for error. It would also be much more difficult to set the rivets. As I've gained more experience with this project, thinking ahead about fastener installation and future maintenance has proven to be very important.
26 Mar 2014 (2 hours, total time to date: 1216.0 hours)
Finished the edges of the upper stringer doublers, removed the clecos along the side of the left stringer (labeled the brackets), clamped a doubler in place, & match drilled through the existing holes in the stringer. I then removed the doubler & laid out the 1 in. rivet spacing between the fuel tank support brackets. I drilled these attachment pilot holes on my drill press using a fence to keep the line straight. I then replaced the doubler & match drilled the new #41 pilot holes through the stringer. I removed the doubler, clecoed the brackets on the doubler to mark the edges to be cut around the brackets. I removed the brackets & used a Dremel cut-off wheel to make the cuts in the doubler. I drilled holes at the corners, then cleaned the edges with 1/4 and 1/2 in. drum sanders. Finally, I replaced the brackets on the stringer & clecoed the doubler in place.
27 Mar 2014 (2 hours, total time to date: 1218.0 hours)
Fit the right upper stringer doubler in the same manner as the left side. Clecoed it in place on the right side.
29 Mar 2014 (2 hours, total time to date: 1220.0 hours)
Cut 0.040 thick, 2 inch wide doublers for the lower engine mount stringers and finished the edges. I laid out the fastener locations at the front and rear of the lower stringers & fabricated a drilling guide to locate the center of the stringer channel. I drilled out the #41 pilot holes at these locations in the lower stringers. These will be the endpoints for the fastener row along the lower stringers.
30 Mar 2014 (2 hours, total time to date: 1222.0 hours)
Clamped each doubler in place on the lower stringers, keeping the lower edge of the doublers flush with the lower edge of the stringers. Match-drilled the fore & aft pilot holes through the doublers from the inside, removed the doublers, marked a straight line between the pilot holes, laid out the 1 inch fastener pattern, & drilled the remaining #41 pilot holes in the doublers on my drill press (using a fence to keep the line straight). Replaced the doublers (used clamps in the middle to keep them tight against the stringers), and match-drilled the pilot holes through the doublers. Then, I started work to add an attachment strip to the firewall flange. I used a fine file to de-burr the edges of the flange tabs. I bought a Roper Whitney #5 hand punch for another project, and thought it may be a good tool to use for the holes in the firewall flange. I tried it out on my damaged firewall punching out 3/32 holes, and it seems to work well.
31 Mar 2014 (1 hour, total time to date: 1223.0 hours)
Laid out and punched 3/32 pilot holes along the upper half of the firewall flange. I had to drill holes in the areas around the engine mounts, but I'm happy with how the hand punch works.
1 Apr 2014 (1 hour, total time to date: 1224.0 hours)
I cut a 1.8 in. wide strip of 0.032 sheet to use as the attachment strip for the engine cowl along the upper portion of the firewall. I finished the edges square to just over 1.75 in. wide and started work back drilling the pilot attachment holes through the firewall flange using 12 in. #41 bits.
2 Apr 2014 (1 hour, total time to date: 1225.0 hours)
Finished match drilling the attachment strip pilot holes around the upper strip. One of the attachment holes on each side (at the corners where the wooden spacers are located) could not be back-drilled. I used a strap duplicator to locate and drill these holes. Once this was done, I removed the upper strip, lightly de-burred it, and carefully added curvature to the strip by hand to better match the profile of the upper firewall. Then, I started work laying out & punching the pilot holes along the lower left firewall flange.
3 Apr 2014 (2 hours, total time to date: 1227.0 hours)
Finished laying out the pilot attachment holes along the lower left side of the firewall, but I had to center punch & drill the last 6 holes since the jig supports block access to the flanges in this area. I then repeated the process along the lower right side of the firewall. I then cut & finished the edges of 2, 0.032 x 1.8 in. wide attachment strips for the left and right sides of the firewall.
4 Apr 2014 (2 hours, total time to date: 1229.0 hours)
Clamped the lower firewall attachment strips in place and used a duplicating strap to drill the pilot attachment holes working my way up from the bottom. I started the bottom hole in the strip by measuring the location on the strip and drilling the hole on my drill press. It took a bit of time, and I will need to use fluting pliers at some point to shrink the front side of the strips.
5 Apr 2014 (1 hour, total time to date: 1230.0 hours)
Removed the lower attachment strips & drilled another hole on each side of the firewall flange to attach the lower edges of the upper strip. I attached the upper strip and back drilled this attachment hole. I removed the strip, cut/finished the edges, replaced the lower strips and overlaid the upper strip to mark the trim line for the lower strips. I removed the strip, cut & finished the edges, and replaced the strips on the firewall. Now there is a nice seam line between the strips. I will have to stop for a week because of a business trip. :-(
13 Apr 2014 (4 hours, total time to date: 1234.0 hours)
Back to work....... I added 2 fastener holes along the upper stringer/longeron connection between the first and last two existing fastener holes on the skin side. I had 1.25 inch spacing between the existing 4 fasteners, so I decided to add them to provide a little more capability lower the fastener loads in the first and last fasteners (not that I really needed them, but the space was available). I then laid out the fastener line below the stringer attachment line for the upper skin nut plates, removed the doublers, & drilled the pilot holes in each of the doublers. Once this was finished, I replaced the doublers & laid out a second row of staggered fasteners on the lower stringer doublers. I removed the lower doublers & drilled out these pilot holes. I replaced the lower doublers, and started work to tack rivet the upper doublers in place with 1097-3s. Of course, I needed to use AD426-3s through the forward upper longeron (two holes on each side). After that, I tack riveted the lower stringer doublers with 1097-3s. Once this was done, I started work tack riveting the attachment strips to the firewall flange below the side skin line. The space is very limited (as can be seen in the previous picture). In the area of the splice in the upper strip, the rivet squeezer would not fit (due to the vertical support), so I used my rivet gun to set the rivets on each side. I was able to set 4 more 1097-3 rivets on each side to hold the strips in place. That was enough for me today. Tomorrow, I'll start work laying out cardboard templates for the forward side skins.
14 Apr 2014 (1 hour, total time to date: 1235.0 hours)
Started making a cardboard template for the forward left fuselage skin. The vertical support limits the ability to slide the template into space between the wing attach lugs, I made a smaller template to trace the cut-out pattern for the lugs & transferred it to the larger template. I then cut the larger template to approximate size & taped it in place to be marked for final fitting.
15 Apr 2014 (2 hours, total time to date: 1237.0 hours)
Marked the inside of the template to help determine the proper final dimensions. Removed the template, trimmed it, made a few minor adjustments, replaced it, & checked it one more time. Then, I traced the pattern on a sheet of 0.032 2024-T3. I made the initial cuts slightly over-sized using a cut-off wheel on my die grinder, & did some light finishing work on the edges of the skin.
16 Apr 2014 (1 hour, total time to date: 1238.0 hours)
I used my 4 in. PVC sheet rolling tool to add curvature to the bottom of the left forward skin & did an initial test fit on the airframe. The wing attach cut-outs were a little tight, so I marked the areas for trimming, removed the skin, trimmed, & finished the edges. I also tightened up the curvature where needed & replaced the skin.
17 Apr 2014 (1 hour, total time to date: 1239.0 hours)
Double checked the position of the left front skin, clamped it in place on the upper stringer, & used a strap duplicator to drill the forward upper attachment pilot hole on the firewall attach strip. This hole is located at the upper firewall stand-off, so I couldn't match drill the hole from the back side. Then, I proceeded to match drill the remaining pilot attachment holes along the upper left stringer & clecoed the skin in place. I then placed the cardboard skin template on the right side to be sure that it matched the dimensions required on the right side (Murphy was an optimist). It looked good. Finally, I laid out the template on another sheet of 0.032 2024-T3 and marked the initial cutting lines.
18 Apr 2014 (2 hours, total time to date: 1241.0 hours)
I re-checked the template lay-out one more time. I plan to over-wrap the aft portion of the forward skin beyond the bottom skin flange since the flange can not be attached securely to the bottom skin where it meets the bottom flange of BH73.75. I want to be able to pick up the rivet hole in the BH73.75 bottom flange inboard of the bottom skin flange. Therefore, I need to be sure that I will have enough material to make that happen. It looked good, so I made the initial cuts for the right forward skin using a cut-off wheel in my pneumatic die grinder (as I did for the left forward skin). I also lightly finished the edges and inside corners of the wing attach cut-outs in the same manner as the other side. I added curvature to the lower portion of the skin using my PVC tool, & test fit the skin on the airframe. The initial fit looked good, so I clamped it in position and will drill the pilot attachment holes along the upper stringer tomorrow.
19 Apr 2014 (2.5 hours, total time to date: 1243.5 hours)
Rechecked the alignment of the right forward skin, and used a strap duplicator to drill the upper forward skin attachment hole in the right skin above the engine mount stand-off (as was done for the left skin). I then removed the left forward skin so that I could back-drilled the pilot attachment holes along the right upper stringer. I then removed the right skin & did a little more finishing work around the edges of both forward skins. Finally, I removed the rudder pedals and tunnel so that I could lay out & drill the forward skin attachment pilot holes along the flanges of the tunnel. I decided to use a 1.5 inch fastener spacing along the tunnel flanges to match the pattern used to attach the tunnel sides. I also paid some attention to the location of the forward flange attachment holes since the firewall stiffeners will make it difficult to buck rivets that are under them. I placed the forward holes 1.125 in. aft of the forward edge of the flange. This should make it easier to button up the skin later and provide a consistant spacing between the attachment rivets along the firewall flange. Once I laid out the fastener locations along the tunnel flanges, I used a center punch & my hand air drill to cut the pilot holes. I normally don't do that, but it seemed to be the best way to accomplish this task.
20 Apr 2014 (2.5 hours, total time to date: 1246.0 hours)
I cut a piece of 1x2 to fit inside the tunnel to help support the sides since I will be using cargo straps to pull the skins against the airframe. Then, I replaced the tunnel on the airframe & did a little more work on the lower curvature of the forward side skins. I replaced the side skins & used 3 cargo straps with a 1x2 under the straps along each side. I also cut a piece of 1x2 to support the upper stringers between the firewall & BH73.75 where the center cargo strap was being used. I noticed that the wing attach cut-outs on the left side were in contact with the top of the attachment lugs when the skin was pulled tight, so I removed the straps, left skin, & trimmed/finished the skin cut-outs. I replaced the left skin & straps and began work back drilling (working my way down from the upper stringer) the pilot attachment holes on each skin.
21 Apr 2014 (1 hour, total time to date: 1247.0 hours)
I back drilled the pilot attachment holes for the upper skin attachment nut plates along each side of the forward skin and continued working my way down the side skins - along the firewall flange and BH73.75 (including the side doubler).
22 Apr 2014 (1 hour, total time to date: 1248.0 hours)
I removed the 0.75 inch thick plywood shear panel from the vertical posts supporting the firewall & replaced it with 2 pieces of 1x2 match drilled through the holes in the plywood. This allows me to back drill the remaining holes in the firewall flange. I continued back drilling the pilot holes along BH73.75 & the firewall. I stopped before reaching the lower stringers because I want to remove the skins again and make adjustments to the curvature of the skin and the interface to the lower doublers.
23 Apr 2014 (1 hour, total time to date: 1249.0 hours)
Before removing the forward skins, I wanted to back drill 6 of the pilot holes for the top skin attach nut plates that had been covered by cargo straps. The most forward holes were difficult to see because of the shape of the upper stringers. I solved this issue with a hand held mirror. I marked the location of the lower doubler on each skin, removed them, and re-worked the lower curvature to get a closer fit to the tunnel flange. I then replaced the skins, and this really paid off! The fit is much better than I had expected. Just another example of the benefit of taking more time to get things right. The skins fit much better around the lower corners, and require relatively little tension in the straps to hold them against the tunnel flanges.
24 Apr 2014 (1 hour, total time to date: 1250.0 hours)
I continued back drilling the forward side skin pilot attachment holes. I finished the row of holes above the wing attach fitting & the firewall flange on both sides. I also drilled out several of the attachment holes along the lower stringer/doubler interface to be sure the skins were flush against the lower doublers before I drilled the attachment holes below the lower stringers.
25 Apr 2014 (1 hour, total time to date: 1251.0 hours)
I inserted a furring strip between the cargo straps and the tunnel flange to hold the skin tight and flush, & used my strap duplicator to drill the pilot attachment holes for the overlapping strip on each both sides of the tunnel flange. I then worked my way up each side of the tunnel flange, back drilling the pilot attachment holes. Once finished, I removed the clecos, loosened the straps, and removed the furring strips. I then replaced the clecos and removed the cargo straps. The forward side skins are now fit on the airframe!
26 Apr 2014 (2 hours, total time to date: 1253.0 hours)
I removed the forward/center skins from the airframe, did some light de-burring & cleaning. Now that the skins have been fitted, I can resume work inside the tail cone. I drilled out the "tack" rivets holding the right tail cone skin to BH99.35.
27 Apr 2014 (3 hours, total time to date: 1256.0 hours)
I cut two 28.5 x 4.5 x 0.040 in. blanks to be bent to form "Z" beams to support the elevator bellcrank housing and avionics decks between BH99.35 & BH128. I finished the edges & laid out the bend lines. I can't make all 3 bends for each beam on my bench top brake, so I started by braking the bend lines slightly for the upper two bends that will form the top of the beams. I then bent the base of each beam, & finished the bends to 90 degrees using my flanging tool (see Jan2, 2013). I'm very pleased with how these have turned out so far - I managed to get them both to match. I then got out my folding table saw & cut a 5 degree bevel in a piece of oak 1x2 to be used as a forming block to make the bend for the upper leg of the beam. The bevel will help me get the bend to 90 degrees accounting for the normal spring back. Finally, I sanded a 3/16 bend radius in the upper corner of the oak forming block.
28 Apr 2014 (1 hour, total time to date: 1257.0 hours)
Drilled tooling holes at a 6 inch spacing along the forming/backing blocks. I then cut out a piece of 0.040 to practice making a bend with the blocks. I placed the practice piece between the blocks, drilled the tooling holes through the sheet, bolted the pieces together, & made the bend with a plastic mallet. It worked out well.
29 Apr 2014 (1 hour, total time to date: 1258.0 hours)
Taped one of the tail cone beams in place on the oak forming block & match drilled the tooling holes through the web. Then, I removed the beam, de-burred the holes, replaced the beam, & bolted the forming/backing blocks together. I used pieces of 2x4 to provide clearance with the lower beam angle, clamped the blocks in a vise, and carefully bent the upper flange with the mallet (as I did with the practice piece).
30 Apr 2014 (1 hour, total time to date: 1259.0 hours)
I repeated the process I used yesterday to bend the upper flange of the second tail cone beam.
1 May 2014 (1 hour, total time to date: 1260.0 hours)
I bent the final edge flanges on each beam using my bench top brake & flanging tool (to finish). I have a little more work to do to tweak the bends, but am happy with the results so far.
2 May 2014 (1 hour, total time to date: 1261.0 hours)
Started work fitting the tail cone beams along the inside of the bottom skin. The first step was to replace the bellcrank housing and reconnect the forward push rod. I had cut the new push rod tube long, so I had to check the location of the housing. I wanted to get the center of the bellcrank travel along a line normal to the bottom skin. This puts the center of travel vertical to the vertical C/L of the housing. I placed the forward edge of the bellcrank housing 5 inches forward of BH99.35. This gives a little more room for the forward supports for the avionics deck and places the center of the bellcrank 8.5 inches aft of BH99.35. I trimmed approx. 1 inch off of the push rod, cleaned up the cut, & test fit the push rod to check the travel of the bellcrank. The push rod is still approx. 3/16 in. too long, but I will take care of that tomorrow.
3 May 2014 (2 hours, total time to date: 1263.0 hours)
I removed the push rod and trimmed 3/16 off. I finished the edge & replaced the tube again to re-check the bellcrank travel. The travel looked good. I removed the tube and housing again to allow me to position the tail cone beams between BH99.35 & 128. I then replaced the housing and push rod tube again to see how it all fits together. I will need to trim the beams to allow for a better fit and to eliminate unnecessary material. I will also need to fabricate angle clips to attach the beams to each BH. I marked some rough reference points, removed the tube, housing, & beams. Finally, I measured and marked the beams for trimming.
4 May 2014 (4 hours, total time to date: 1267.0 hours)
I took the stabilizer down to Warren Co. Airport so that Jasson Czaika (my IA) could inspect the Cherry Max rivets along the forward frame & grind out any that he thought were loose. I found a few that I thought were no good, but grinding them out is not easy. This is the second time that I've taken the stabilizer back to Jasson, and is why I try much harder to avoid using Cherry Max rivets. Jasson also found 3 loose rivets ground them out and punched the pins for me. I then drilled them out & we installed a standard AN426-4 in one location (where we could get an arm inside), and he installed two new Cherry Max rivets in the other (less accessible) locations. Since the stabilizer was finally ready to be finished, we worked together to squeeze the remaining rivets along the top skins. I'm glad to get this done. When I got back home, I went back to work on the tail cone beams. I cut the beams along the trimming lines I drew yesterday, did a quick test fit, made a few adjustments, & finished all of the cut edges.
5 May 2014 (1 hour, total time to date: 1268.0 hours)
I laid out a C/L on a piece of flat plywood to use as a platform to fit the bellcrank housing inside the tail cone beams so I can drill the pilot attachment holes in the beams on top of my work table. I centered the beams on the plywood, replaced the bellcrank housing (I had marked the position earlier), and match drilled the attachment holes through the beams. I then starting locating the attachment hole locations along the beams.
The bottom plate shown between the housing and the beams is temporarily holding the base of the housing in place & will be used to hold the beams in position until I match drill the beams on the bottom tail cone skin.
The bottom plate shown between the housing and the beams is temporarily holding the base of the housing in place & will be used to hold the beams in position until I match drill the beams on the bottom tail cone skin.
6 May 2014 (1 hour, total time to date: 1269.0 hours)
I finished laying out the fastener locations along the base of the tail cone beams & drilled the #41 pilot attachment holes. I then replaced the beams/housing on the plywood jig. I used a hole spacing of 1.25 in. except toward the aft end, where I extended the spacing to approx. 1.35 to even out the spacing at that end. I also used two rows of fasteners on each side of the bellcrank housing where the base of each beam was wider to support the housing and potential moment that can be applied at the bellcrank.
7 May 2014 (1 hour, total time to date: 1270.0 hours)
I fabricated a 0.75 in. wide strap from some 0.032 thick aluminum to hold the aft end of the beams at the proper spacing while being installed in the tail cone. I match drilled the strap through the existing aft pilot attachment holes. I inserted AD426-3 rivets (did not set them) through the bottom of the beams to hold the strap in place, and covered the heads with duct tape to protect the tail cone skin. I used NAS1097-3 rivets in the same manner to hold the base plate to the beams. The 1097's worked better because of the smaller heads & I will be match drilling the attachment holes in the tail cone around the area of the housing first. Unfortuneatly, I was unable to fit the assembly in the tail cone because of the total width could not be turned to the side sufficiently to slide under the flanges at BH99.35 & 128. I removed one of the beams and installed each side separately, then re-connected the assembly. Once in place, I realized that I neglected to cut the ends of the beams to approx. 10 degrees to match the slope of the bottom skin and allow the forward end to be parallel to the BH webs. I will have to remove the assembly and fix this tomorrow.
8 May 2014 (1 hour, total time to date: 1271.0 hours)
I removed the beams from the tail cone & used a disk sander to trim the ends to account to the taper of the bottom skin. I then replaced the beams in the tail cone & re-alligned the assembly. To be sure the bellcrank housing attachment holes will match, I also replaced the housing in the assembly. I then match drilled the attachment holes through the housing/base plate/beam/tailcone skin. I didn't drill every hole - just enough to secure the assembly. I'll drill the rest through the beams after I removed the rest of the assembly.
9 May 2014 (1 hour, total time to date: 1272.0 hours)
I removed the bellcrank housing/tail cone beams, removed the spacing plates, removed the protective plastic from the beams, & de-burred the beams. I then replaced the beams and housing spacing plate back in the tail cone & finished match drilling the remaining pilot holes for the bellcrank housing. I vacuumed the aluminum chips out of the tail cone, removed the spacing plate, & replaced the bell crank housing. I still have to drill out the remaining beam attachment pilot holes in the aft portion of the beams. This will be easier to do after I take the clecos out of the right tail cone skin, and pull the skin out of the way to get into the tail cone.
10 May 2014 (3 hours, total time to date: 1275.0 hours)
I removed the clecos on the right side of the tail cone to gain better access to finish drilling the remaining pilot holes along the aft end of the tail cone beams. Although it provided better access, I really need to remove the rudder and fin so that I can completely remove the right tail cone skin. Without the right skin in place, the tail cone is very flexible, and I'm concerned about installing anything that could affect the BHs and cause problems getting the skin back on. I will have to be very careful installing a bracket to hold rudder pulleys on BH160. For now, I replaced the skin and began work to install 0.032 angles along the lower sides of the bottom tail cone skin to support avionics decks on each side of the bellcrank housing. I cut & bent two pieces of 11 x 1.75 x 0.032 sheet, trimmed the flange to be mounted to the skin to 0.75, marked/drilled #41 pilot attachment holes at 1 in. spacing, and began fitting them in the tail cone. I decided to build the deck parallel to the tail cone beams to keep the deck as low as possible, and also make the attachment as close as I could to the more vertical portion of the skin. My compromise ended up to be 2 inches above the top of the beams. I also have to allow room aft of BH99.35 to accommodate the recessed seat back (3 in.). I allowed for 0.375 clearance when locating the forward edge of the angles, and match drilled the first attachment hole through the forward hole in the left angle. This placed the deck approx. 0.5 in. above the top of the rear spar.
11 May 2014 (2 hours, total time to date: 1277.0 hours)
I finished the alignment work for the tw0 angle brackets & matched drilled the remaining pilot attachment holes on each side of the bottom tail cone skin. I then began work fabricating "legs" from 1 x 1 x 0.062 angle stock to support the inside edges of the two avionics decks.
12 May 2014 (1 hour, total time to date: 1278.0 hours)
After thinking it over, I decided to abandon the idea of using the 0.062 angles to support the avionics decks. Instead, I think it will be better to use a piece of 0.032 thick sheet attached to the inside of the tail cone beam web with a flange bent on the top to support the inside edges of the decks. It will require a few stiffeners to span the upper portion of the sheet (above the upper flange of the beams), but will be much easier to fabricate and install. I cut, finished, and bent the flange in two pieces of 0.032 stock. I also started work fitting the pieces on the tail cone beam.
13 May 2014 (1 hour, total time to date: 1279.0 hours)
I finished fitting the new avionics deck supports and clamped them in position on the tail cone beams. I removed the left beam, MMD'd #40 pilot attachment holes at 4 positions along the tail cone beam web (2 fasteners at each location). I then removed the right beam in preparation to MMD the pilot attachment holes.
14 May 2014 (2 hours, total time to date: 1281.0 hours)
I MMD'd the pilot attachment holes for the right deck supports. The upper holes are just under the edge of the upper side flange of each beam, so it will be difficult to set these rivets. I decided to cut notches in the side flanges to accommodate the rivet squeezer. I used a 0.75 inch hole cutter to make the notches. a piece of 1 x 2 with a 1/8 in. pilot hole positioned at the edge of the flange. I clamped the 1 x 2 at each location and SLOWLY cut each notch. The problem to overcome was the fact that the cutter was striking the edge of the flange, so the wood had to be clamped tightly to flange and the cutter had to be lowered very slowly to gradually cut into the free edge. Once this was complete, I used a 0.5 in. diameter sanding wheel to smooth and contour the cuts and make any adjustments that I thought would make it easier to set the rivets and reduce the stress concentration at the notch root. Finally, I used fine sandpaper and scotch brite to finish the cut edges.
15 May 2014 (1 hour, total time to date: 1282.0 hours)
I cut stiffeners for the upper portion of the deck supports from previously bent 0.025 sheet stock (0.75 x 0.75 flanges). I then laid out a 3 fastener hole pattern on each leg, drilled the #40 holes, tapered the opposite leg, and finished the edges.
16 May 2014 (1 hour, total time to date: 1283.0 hours)
Laid out the stiffeners along the 4 existing rivet lines on each deck support. Match drilled the attachment holes, indexed each stiffener (labeled each stiffener with a number and orientation info) as I removed them, and began work de-burring the stiffeners & deck supports.
17 May 2014 (2.5 hours, total time to date: 1285.5 hours)
Finished de-burring the stiffeners and their attachment holes in the deck supports. Drilled the attachment holes between the supports and beams to #31, cleaned up the holes, reassembled the parts, and finished with a 1/8 bit. Removed the parts again to do a final de-burr and finish. Then, I used a C-frame dimpler to dimple the #40 attachment holes for the stiffeners and the #30 holes for the support/beam interface. The 1/8 holes work well when dimpled using a #30 die - the resulting expansion brings them up to size nicely. Finally, I used the dimpler to make one final pass at each hole with the parts assembled (1 or 2 moderate strikes). This helps to get the matching dimples fully seated. I believe this was a source of the problem I had with the stabilizer skin and those Cherry Max rivets.
18 May 2014 (3.5 hours, total time to date: 1289.0 hours)
I needed to come up with a way to keep track of the stiffener location/orientation when I cleaned them up for acid etch/alodine. I decided to tie a length of string around the upper attachment hole of each stiffener and tie knots in the string, corresponding to the number I had assigned to each one (1-4 on the right and left). I also used a red marker to color the knots for the left side and a blue (didn't have a green) one for the right side. I de-greased, etched, and alodined all of the stiffeners and both deck supports. I let the parts dry, then applied a light coat of primer to the mating sides of the parts, and let that dry for a few hours. Then, I clecoed the stiffeners on each support, and used my rivet squeezer to set the -3 flush rivets. I ended up drilling out 5 rivets and replaced them with NAS1097-4s. Finally, I clecoed the supports on the tail cone beams and replaced the beams in the tail cone.
19 May 2014 (1 hour, total time to date: 1290.0 hours)
Measured & cut out cardboard templates for the left & right avionics deck. I marked the bend lines and test fit each template in the tail cone. I made a few minor adjustments to the templates, removed the supports along the tail cone skin, & trimmed/finished the forward, lower flange to make a better fit for the decks.
20 May 2014 (1 hour, total time to date: 1291.0 hours)
Marked and cut out the deck blanks using the 0.032 thick seat from MA. I won't be using this part since I'm going to make some changes to the seat design. De-burred the edges & bent the forward flanges on each deck. I laid the parts on the deck supports to check the fit before making the aft bends, & made trimmed/finished the edges for a better fit. Once I was satisfied with the fit, I made the aft bends. Finally, I measured & marked the location of the outside support flanges on each deck in preparation to drill the nut plate attachment holes.
21 May 2014 (2 hours, total time to date: 1293.0 hours)
I removed the left deck support to measure the location of the stiffeners to ensure sufficient clearance for nut plate installation for the left deck installation. I will use 4 nut plates on each side, and need to position them so that I will be able to reach the nut plate attachment holes with my squeezer. Once I determined the locations along the inside support, I drew the fastener line across the left deck to locate the holes on the outside support. I used the two lines in the middle to attach 0.032 angle stiffeners for the deck. I then drilled 4, #40 pilot holes along the outside of the left deck, replaced the deck & marked the hole locations on the support with a sharpy marker. I then removed the deck and outside support, lined up the marks, clamped the deck in place, & match drilled the pilot holes on my drill press. I replaced the parts in the tail cone & measured the location of the deck on the inside support. I then, removed the deck, measured the location of the inner support flange, removed the deck, & drilled the forward pilot attachment hole in the deck. I replaced the deck and marked the location of the attachment hole on the inside support flange. I then removed the inside support, carefully drilled this hole in the flange, replaced the support/deck, & clecoed everything in place. I double checked my measurements for the remaining holes along the inside support flange, removed the deck, & drilled the remaining 3 pilot holes in the left deck. I replaced the deck & match drilled the attachment holes in the inside support flange. I removed the deck (again), and cut two 0.032 angle supports to fit across the deck. I used the material from the kit seat for the angle stiffeners since they were already bent and there's no reason to waste them. I MMD's the attachment holes for the stiffeners, and trimmed/finished the edges. Finally, I clecoed everything together, and put the deck back in the tail cone.
22 May 2014 (1 hour, total time to date: 1294.0 hours)
Started work installing the right avionics deck following the same procedure that I used for the left deck. I finished drilling the pilot attachment holes along the outside support, laid out the fastener pattern for the inside, and match drilled the aft hole through the inside support.
23 May 2014 (1 hour, total time to date: 1295.0 hours)
Finished match drilling the pilot attachment holes along the inside left deck support. I then cut out the deck stiffeners, finished the edges, drilled the pilot attachment holes, & match drilled the stiffener attachment holes through the deck.
24 May 2014 (1 hour, total time to date: 1296.0 hours)
I didn't get much done today since I went flying with a couple of friends. I cut 4, 1 x 1 x 0.062 angles to stiffen up the inside deck supports. I don't have much room between the tail cone beams, but leaving the angle fillet on the edge provides quite a bit of additional stiffness, and tapering it at at the bottom will provide the clearance needed for the bellcrank housing. Once I had the stiffeners cut & trimmed, I finished the edges.
25 May 2014 (4 hours, total time to date: 1300.0 hours)
Today was a different story. I laid out the fastener hole location on the 0.062 stiffeners, drilled out the #40 pilot holes, & match drilled the holes though the vertical supports and tail cone beam webs. I also decided to trim/re-finish the upper side flange between the notches previously cut for access to the rivet heads along the upper web of the beams. I then drilled out the fastener holes to 1/8, then to #30. I disassembled the parts, C/S all of the holes in the stiffeners, de-burred all of the holes, & finished with scotch brite. I de-greased, etched, & alodined the parts. Once everything was dry, I applied a light coat of primer to all of the mating surfaces.
26 May 2014 (4 hours, total time to date: 1304.0 hours)
I riveted the right and left avionics deck supports and stiffeners to each tail cone beam. There was no way to use my rivet squeezer for most of the rivets, so I clamped each beam to my work table and used my rivet gun. It took a little time, but I guess carefully driving 32 rivets by myself wasn't too bad. I had to cut rivets to 3 different lengths to fit through the differing number of layers. I've found that cut rivets are more difficult to drive straight, but dressing the cut edge with my scotch brite wheel helps a lot. The picture shows the completed right beam after a little over 2 hours of effort.
27 May 2014 (1 hour, total time to date: 1305.0 hours)
I replaced the assembled tail cone beams in the aircraft and checked the fit of the decks on each side. They fit like two gloves :-) Then, I removed the decks, drilled out the stiffener attachment holes to 1/8, de-burred the holes, and dimpled them using my C-frame dimpler.
29 May 2014 (1 hour, total time to date: 1306.0 hours)
I de-greased, etched, & alodined the stiffeners and decks. When dry, I applied a light coat of primer to the mating surfaces.
30 May 2014 (1 hour, total time to date: 1307.0 hours)
I riveted the stiffeners to the avionics decks and replaced the decks in the tail cone.
31 May 2014 (2 hours, total time to date: 1309.0 hours)
I measure the approximate size of a bracket to attach the upper tabs of the bellcrank housing to the avionics decks and made a cardboard template to check the fit. These brackets will help to provide additional stability to the bellcrank housing. It doesn't need much lateral support, but it would be nice to have some backup in the longitudinal direction. Besides, I already have the tabs on the housing, so I may as well use them. Once I got the fit the way I wanted, I fabricated the brackets out of the remaining scrap from the 0.032 seat provided by MA. I made the bends with my bench top brake, and adjusted them using my flanging tool. I'm going to tie the brackets into the decks with #8 machine screws at the forward 3 inside deck attachment holes. I placed the brackets in position & taped them securely to the decks. I removed the decks, clamped the brackets to the decks, & match drilled the pilot attachment holes. I then replaced the decks/brackets to check the fit.
1 June 2014 (3 hours, total time to date: 1312.0 hours)
Removed the bellcrank housing, laid out the location of the bracket attachment holes in the upper tabs (making sure to have adequate room for the nut plate rivets), & drilled the #41 pilot holes (2 on each tab). Replaced the housing & used my strap duplicator to locate/drill the holes in the brackets. I then removed the brackets, trimmed the edges and used my dremel tool to cut nice inner radii at the tab roots. I then finished the edges of the bracket. Later, I plan to fabricate 0.025 thick angle stiffeners to rivet along the 4 exposed edges - just to keep them stiff & protect them a bit more from bending down the road in case something gets dropped on them. Then, I started back to work on the cockpit. I drilled out the rudder cable pass-through holes in BH99.35 to #12 & ran the cables through. I had to move the center of the right hole over slightly to the right for better alignment with the pass through holes in the seat BH & BH73.75. I re-installed the seat BH to locate the holes in the fuselage skin for the flap torque tube. I cut a piece of 0.75 in. wood dowel to fit inside the cockpit through the torque tube stand-offs. I trimmed the ends to match the inside skin curvature, installed the stand-offs with the dowel, & traced the openings on the inside of the skin.
2 Jun 2014 (1 hour, total time to date: 1313.0 hours)
I located the center of the flap control openings, center punched the location, and drilled a 1/8 in. pilot hole on each side. I then used a 0.75 inch hole cutter on each side (backed up with a scrap piece of 2x4). I then trimmed the cut-outs to final shape with a 1/2 in. dremel drum sander & finished the edges. Finally, I replaced the flap control torque tube to check the fit.
3 Jun 2014 (1 hour, total time to date: 1314.0 hours)
I had not been able to drill the attachment holes in the upper 2 tabs in the seat support BH from the inside, so I decided that today was a good day to get this job done. I traced the location of the tabs on the bottom skin, removed the BH, measured the location for the hole along the existing rivet line, & drilled the #41 pilot holes through the skin. I then replaced the BH & drilled the pilot hole through from the outside. Instead of continuing with the cockpit structure right now, I think it would be better to wrap up work inside the tail cone & get it zipped up. Once that is done, I can start working my way forward and get the center, bottom skin attached before finishing the seat & other structure inside the center section. So, I measured and marked the desired location for the rudder cable height at BH160. After looking at the way the cable runs from the rudder through the fin spar and BH177.5, the straight line runs close the the A/C C/L at BH160. The only way I can make this happen is with a set of pulleys at BH160. To do this, I'll need to add something to attach the pulleys since the straight line through the existing holes touch the inside of the BH web. Anything in that area will be close to the large aluminum push rod tube, so I re-installed the tube & checked to be sure I know where it will be to attach to the elevator control horn. It looks like I will need to extend the hole in BH177.5 for the push rod extension down about 1/2 in. In any case, I marked the location for the cables and cut a 1x2 to lay across the tube so that I will know how to provide clearance for the tube when I fabricate the mounting structure for the cable pulleys. I'm a bit disappointed with the lack of information in the construction information. Chris at MA still has not called me back, so it's pretty clear that I'm on my own here (just like I was with the elevator bellcrank housing). In fairness, most people make changes to various parts of the design, and adding equipment behind the seat will always require a lot of changes. However, the plans clearly call out the location of the holes in BH177.5 for the control cables and push rod extension. Therefore, it seems reasonable to expect more information about this sort of thing - especially since there is no way the push rod extension will fit through the hole as called out in the plans and attach to the elevator control horn. Enough venting....... back to work.
4 Jun 2014 (1 hour, total time to date: 1315.0 hours)
I removed the rudder/fin & set them aside in preparation for removed of the right tail cone skin. I then fabricated a transfer strip with #41 pilot holes with a 1 inch spacing to use on the right skin (behind the stabilizer) to attach a stiffener which will take out a slight depression in the skin in that area. I marked the fastener location, taped the transfer strip to the tail cone, & match drilled the holes through the skin.
5 Jun 2014 (1 hour, total time to date: 1316.0 hours)
I cut a piece of 0.625 x 0.625 x 0.032 angle (I had bent a few of these some time ago) to fit inside the right skin & laid out/marked the fastener line with a sharpy. I decided to orient the outstanding leg toward the top so that it would be easier to get a bucking bar to the rivets by reaching through the aft tail cone access hole. I may end up using Cherry Max rivets, but I'd rather keep my options open. I laid the angle over the edge of a 1x4, taped the transfer strip to line up with the fastener line, & match drilled the #41 pilot holes through the angle stiffener. I de-burred the holes & clecoed the stiffener in place. It really did the trick! Now, I believe that the depression (wrinkle) was the result of whatever happened to pull the right side of BH177.5 forward (probably had the cargo strap too tight??). Anyway, after the stiffener was clecoed in place, I ran through all of the holes (in two passes since I needed to swap out the clecos) with the #41 bit. I toyed with the idea of using epoxy and -3 rivets to attach the stiffener, but since the stiffener is 0.032 thick, I may as well use -4s and take better advantage of the stiffener's load carrying capability. Not that the epoxy won't carry the load, but it's a lot simpler to just go with the larger rivets in this situation and it gives me the option to go with Cherrys and eliminates any worry about dis-bonds down the road.
6 Jun 2014 (2 hours, total time to date: 1318.0hours)
I drilled out the stiffener attachment holes to 1/8 in. (they will expand after being dimpled). Then I prepared the right tail cone skin for removal (hopefully for the last time) by drilling out the longeron attachment holes and the attachment holes on the upper portion of BH99.35 to 1/8 in. I then removed the skin and de-burred the 1/8 in. holes. Finally, I designed a doubler to use on BH177.5 to reinforce the area around the elevator push rod extension since I know I will need to extend the pass thru hole down to connect to the elevator control horn.
7 Jun 2014 (3 hours, total time to date: 1321.0 hours)
I cut out the 0.032 doubler to install around the elevator push rod pass thru hole in BH177.5. I'm sure it's a bit of overkill, but when I elongate the pass thru hole, it will come out at the top of the transverse BH attachment flange (terminating at the fuselage C/L hole). I wanted to be sure to remove this small hole to eliminate a potential crack initiation site in BH177.5. I simply don't know how much torsional load will be transferred into the web, so I've opted for a little more back-up here since a repair would be very difficult after the tail cone is assembled. I tied the doubler through the existing transverse BH flange attachment holes & extended it down to pick up 3 rivets below the flange for a more gentle transition of load into the web. I marked the C/L of the doubler, taped it in place, & marked the location of the BH attachment holes on the doubler from the outside with a sharpy marker. I removed the doubler & carefully drilled a 1/8 in. hole in one of the inside holes and #33 holes at the other 3 locations. I clecoed the doubler in place through the 1/8 inch hole, and used 2, -3 rivets to help locate the doubler at the two outside holes. This is a bit convoluted, but I didn't think I'd be able to use a strap duplicator for this process. There is not a direct line through these holes from the outside, so I had to use a long 1/8 in. drill bit. The reason for the #33 holes was to facilitate the drilling process with minimum damage to the existing holes, and allow me a little room for error in the initial hole placement. Once I got the 1/8 in. holes drilled, I clecoed the doubler in place and "reamed" each hole out to #30 from the inside. This took some time, but the holes look very good. I then drilled 1/8 pilot holes for the push rod and elevator pass-thru holes, and cut these holes with my hole cutter. Then, I laid out the remaining fastener holes & match drilled them (#31) from the inside. I removed the doubler, match drilled the lower #31 fastener holes into a piece of 1x4. I used a small round file to create a notch at the base of the elevator pass thru to accommodate a pilot hole for my hole cutter to elongate the hole down to the A/C C/L. I drilled the 1/8 pilot hole in the 1x4 & cut the 0.75 hole to elongate the pass thru. I then cut a notch on each side of the doubler, terminating at the edges of the rudder cable pass thru holes. I then cleaned everything up with a dremel drum sander. I essentially duplicated the process of elongating the pass thru hole in BH177.5 by clamping/clecoing a small piece of wood on the outside of the BH. Once this was done, I clecoed the doubler in place and finished the pass through with the dremel drum sander to match the doubler and completely remove the C/L hole in BH177.5. I also drilled the doubler attachment holes out to 1/8 in. - I'll take them all out to #30 right before I etch/alodine the doubler. Finally, I did more clean-up work on the doubler and put it back on the BH. I will break the sharp corners on the outside of the doubler before I rivet it in place. Probably more than I really need, but I really don't want to have to repair this area later.
8 Jun 2014 (3 hours, total time to date: 1324.0 hours)
I spent some time fabricating a pulley support bracket from some 2024-T3 1 x 1 x 0.062 angle stock. I'm going to have to mount the rudder cable pulleys on BH128 & 160, so I want to keep them as light as possible. I'll have to tailor each bracket to the application and do all of the stress analysis for each case, but I think it will be better to use the aluminum brackets since I will have a lot more flexibility in the design at each location. I spent a lot more time going through design options for the installation at BH160. At first, I looked fabricating a piece of 0.032 flanged web across the inside of the BH with a cut out for the push rod tube. This was just too convoluted. I re-checked the location of the cable at the BH, and thought it might be possible to run the cables through the tooling holes in the BH web. This will not work - just brings the cables too far outboard. I'm going to re-check this again, but I'm fairly certain that the cable will have to run right at the exiting edge of the BH web, so I'll probably have to run a flanged doubler to extend the width of the web and find a way to add enough strength to support the cable loads. I came up with a few possible ideas, but will wait to post the one that seems best.
9 Jun 2014 (1 hour, total time to date: 1325.0 hours)
I finished fabricating a "jig" to locate the rudder control horn attachment holes behind BH182. The airframe wont support the fin/rudder without replacing the right side skin. I already had marked the vertical placement of the cables at BH160, but I want to double check the laterial location with the jig. I clamped the jig in place and ran some 1/8 in. twine to establish the rudder cable path through the tail cone. I ran the twine along both sides and drilled the pass thru holes in BH160. The picture shows how this looks for the right cable run. The pass-thru is in the bend radius of the internal BH web flange. Of course, I'm going to need to install a doubler in the web to reinforce the BH and carry the additional loading from the cable reaction at the pulley.
10 Jun 2014 (1 hour, total time to date: 1326.0 hours)
I worked through a few different ways to bridge the rudder cable tension loading at BH160, and the most efficient way for me to do it is to go back to my initial thought of going accross (laterally) with flanges at the bottom and top to take the maximum bending moment. The issue is caused by the cable turn at BH160 and 128. This will result in longitudinal and vertical reactions. The turn angle is approx. 25 degrees - resulting in a net longitudinal load of approx. 10% of the cable tension. The vertical load will be approx. 42%, which is no problem since it is easily sheared into the skin through each BH (even with the max shear from the horizontal stab ~ 500 lbs on each side). The problem is how to take the longitudinal load at the inside of the BH web. A cable tension value of 1000 lbs seems very high, but sizing the structure for it would make me feel better. Bridging 100 lbs on each side across the width is a lot easier than trying to do it across the height of the BH. The only other issue is dealing with a large opening that I will need for the elevator push rod tube. So, I replaced the push rod again and started laying out cardboard templates to size the pulley support structure.
11 Jun 2014 (1 hour, total time to date: 1327.0 hours)
Finished the cardboard template, double checked the measurements/clearance, and cut out the 0.040 thick blank.
12 Jun 2014 (1 hour, total time to date: 1328.0 hours)
I marked the bend lines for the flanges, and bent the lower flange. I then located the centers for two, 2.25 in. dia. holes to form the "racetrack" opening for the 1.5 in. elevator push rod tube to accomodate its vertical motion and facilitate installation/removal. I drilled 2, #30 holes in areas that will be removed by the hole cutter to locate the part on a scrap piece of 1x4 and drilled the pilot holes for the hole cutter. Finally, I cut both holes and made the upper flange bend.
13 Jun 2014 (0.5 hour, total time to date: 1328.5 hours)
I didn't have time to do much today. I used a dremel drum sander to flatten the sides of the race track cut out in the pulley support reinforcement & finished the edges. It's ready to be fit on BH160, but I will be out of town for the next week, so work will be on hold until I return.
21 Jun 2014 (1 hour, total time to date: 1329.5 hours)
I'm home, but a little under the weather, so I didn't get too much done today. I positioned the pulley support on BH160, clamped it in place, and installed the push rod tube to double check the clearance and ability to install/remove the tube. The cut-out was slightly off center, so I removed the tub & support ,and removed some material & refinished the left side of the support. I clamped the support back in position, re-installed the push rod to recheck the fit, & marked the location of the rudder cable holes in the support through the holes in the BH. I removed everything again so I could drill the pass through holes in the support on my drill press. I did this because I wanted to move the center of the holes slightly outboard so that the edge of the holes will not cut through the bend radius in the inside of the BH web when I finally enlarge them to allow clearance for the rudder cables. I drilled #21 pilot holes in the support so that I could use -5 clecos to hold the support in place and over-drill the existing holes in BH160. I then clamped the support back in place on the BH, match drilled the #21 holes through the support, & clecoed them together.
22 Jun 2014 (1.5 hours, total time to date: 1331.0 hours)
I laid out the approximate location of the rudder cable pulley brackets on the support so that I could mark and drill pilot holes in the lower portion of the support to attach it to BH160. Since I don't yet know the exact location/orientation of the pulley brackets (not to mention that I have not fabricated the final version), I will have to wait to drill any attachment holes in areas that will be in common with the pulley brackets. I also checked to be sure that the attachment holes would be accessible with either my rivet gun or squeezer. I laid out & drilled 2 rows of 2 fastener holes at the bottom portion of the support at each side of the BH web. The lowest outside holes are approx. 13/32 from the notch on each side of the BH. This distance would normally be fine, but I decided to fabricate & install 0.032 thick doublers nested inside the BH web across the notches to pick up the bottom row of holes through the support. It makes a lot more sense to do this now rather than have make a repair down the road in case a crack forms at either of the notches. The loading from the cable tension is not conducive to cracking the notches, but there are always unknown unknowns - plus, it provides a nicer transition from the bottom of the support into the BH. I bent a flange in these doublers to sit nicely inside the inner flanges of the BH.
23 Jun 2014 (1 hours, total time to date: 1332.0 hours)
In order to comfortably bridge 100 lbs of longitudinal load from each rudder cable, I will need to beef up the upper flange and the upper portion of the pulley support. I fabricated a 0.032 doubler to nest inside the pulley support (aft facing side). I cut the blank to shape, bent a flange in the doubler to match the radius of the bend in the support, and cut out the two 1.125 in. radius holes that form the race track opening for the push rod tube.
24 Jun 2014 (1 hour, total time to date: 1333.0 hours)
I used my dremel tool to trim the sides of the race track cut-out in the 0.032 pulley support doubler. I then did more finishing work on the pulley support parts. Finally, I started fabricating a 0.040 doubler to go around the outside of the race track cut-out on the forward side of the pulley support. I laid out and made the two 1.125 in. radius cuts in a piece of 0.040 2024-T3 sheet.
25 Jun 2014 (1 hour, total time to date: 1334.0 hours)
I've really been "plodding along" with the pulley support structure for the last few weeks because I've essentially been designing it as I go. It takes so much more time to do anything outside of what's in the plans, but in this case, there was nothing helpful in the plans, so..... Today, I trimmed the inside of the cuts I made for the 0.040 in. ring doubler, laid out the outside pattern, & cut it out on my band saw. Then, I finished the edges. I made the ring a little wider than necessary (~22/32), so I may end up trimming it again later. Finally, I traced the outside of the ring doubler on the pully support and laid out the fastener pattern (~ 1 inch spacing). This brings the thickness around the push rod cut-out up to ~0.112 in.
26 Jun 2014 (1 hour, total time to date: 1335.0 hours)
I drilled the #41 pilot holes around the push rod race track cut-out in the pulley support. I clamped the support doubler in place, match drilled the pilot holes, and match drilled the #21 holes that locate the rudder cable pass-thru holes. I removed the support doubler, taped the ring doubler in place on the pulley support, & match drilled the holes through the ring doubler. Finally, I located two additional attachment holes on the pulley support closer to the cable pass thru holes to hold the support to the BH web so I can remove the clecos at the rudder holes to check the cable run. I will still need to add a 0.062 thick doubler strip on the top of the pulley support upper flange. to carry the maximum bending load, but I will wait until I have located all of the other attachment holes in the pulley support.
27 Jun 2014 (1 hour, total time to date: 1336.0 hours)
Replaced the pulley support structure on BH160 & ran some string along the rudder cable route to check the pass thru location on BH128. I checked both sides carefully to also be sure that I will have room for the pulley brackets. I will definitely need to add more structure in the lower corners to pick up at least one pulley support attachment bolt. I located the pass thru holes, drilled a #30 pilot hole, & ran the string to check it one more time.
28 Jun 2014 (2 hours, total time to date: 1338.0 hours)
I fabricated 2 shear clips from scrap 0.032 sheet, located the fastener holes to attach to the web of BH128. I had to be sure that the holes would be accessible for my rivet squeezer. Then I located the holes between the clips and the tail cone beams. These will have to be attached with Cherry Max rivets since they will have to be done in place. The beams can't be installed with the clips attached. In order to drill the attachment pilot holes, I had to first drill the pilot holes in the clips, cleco the clips on the BH, mark the holes on the beams with a sharpy (I also traced the outline of each clip on the beam), remove the beam/clip, tape the clip back in position, & match drill the pilot holes. I then replaced the beams/clips to verify the fit.
29 Jun 2014 (2 hours, total time to date: 1340.0 hours)
I fabricated 2, 0.040 in. thick pulley supports to attach to the lower corners of BH128 to support the additional longitudinal loading caused by the cable turn between BH128 & BH160. I bent the flanges & located fastener holes to attach the supports to the BH. I drilled #41 pilot attachment holes in the supports (after carefully checking the placement to be sure I can reach the fasteners), clamped them in place & match drilled the holes. I marked the location of the rudder cable pass thru and enlarged these holes out to #19. I will still need to add a stiffener between the two supports, but must keep it as close as possible to the top of the inside flange of BH128 to allow for installation/removal of the elevator push rod through the back of the bellcrank housing.
30 Jun 2014 (1 hour, total time to date: 1341.0 hours)
I started fabricating mounting brackets for the rudder cable pulleys out of 1 x 1 x 0.062 2024-T3 angle stock. The first set of brackets (for BH99.35) will be the shortest so they will fit below the level of the seat. The others will need to be longer because of mounting considerations at BH128 & 160. I set up the drilling fence on my drill press to be able to accurately duplicate the hole pattern on each bracket, and will make at least one spare set of for each location.
1 Jul 2014 (1 hour, total time to date: 1342.0 hours)
I finished making 2 sets of pulley brackets for BH99.35 (including a spare set) & started working on the brackets for BH128. One side of each of these sets is longer to allow for an attachment hole above the BH web flange. I will make the other side the same as the brackets used at BH99.35 since the outside bracket will fit under the flange. The only challenge for the longer side is to provide good clearance between the BH web and the doubler flanges and line up the holes on each side. I finished the longer bracket for the right side.
I'm using a pulley thimble to keep the cable on the pulley. It's a bit overkill, maybe, but the second bolt also stabilizes the bracket assembly. I'll use castellated nuts on the final assembly so that I won't have to overtighten them and the thimble will rotate between nylon/standard washers. I've installed a 1/4 in. O.D. steel bushing inside the phenolic pulley from Aircraft Spruce (A-223). I had to open the pulley hub using an "F" drill bit to accomodate the bushing (0.25 O.D. x 0.035 4130 tube)
I'm using a pulley thimble to keep the cable on the pulley. It's a bit overkill, maybe, but the second bolt also stabilizes the bracket assembly. I'll use castellated nuts on the final assembly so that I won't have to overtighten them and the thimble will rotate between nylon/standard washers. I've installed a 1/4 in. O.D. steel bushing inside the phenolic pulley from Aircraft Spruce (A-223). I had to open the pulley hub using an "F" drill bit to accomodate the bushing (0.25 O.D. x 0.035 4130 tube)
2 Jul 2014 (1 hour, total time to date: 1343.0 hours)
I fabricated the shorter pulley bracket for the right side of BH128. I then removed the left pulley support doubler to determine the length of the longer bracket and the location of the pulley/timble holes as I did for the right side. Ideally, they would be the same, but in reality they aren't - they turned out to be about 2/32 different. I don't have a lot of room for error between the BH and doubler flanges, so I want to get these holes as close as possible to the proper location to make it easier to mount the bracket assembly. Once I get things in place, there will be some adjustments - mostly some rotation of the bracket to align the cable to load the pulleys normal to their axes. I finished fabricating the pair of brackets for the left side at BH128.
3 Jul 2014 (1 hour, total time to date: 1344.0 hours)
I started fabricating pulley mounting brackets for BH160. I measured the length required to allow room for the mounting bolts, cut 4 blanks, & determined the location of the upper holes for the thimble.
4 Jul 2014 (2 hours, total time to date: 1346.0 hours)
Drilled the thimble/pulley attachment holes in the 4 brackets to attach to BH160. I did some light finishing work on the brackets. Now, it's time to align the pulley brackets on the BHs. I replaced the rudder pedals on the tunnel so that I could run a cord on each side to simulate the 1/8 in. rudder cables. I also replaced the wooden "jig" that I made to locate the rudder control horn behind BH182. I needed to enlarge the rudder cable holes at BH160 & 128 to make it easier to run the cord. The cable run looks very good (passes through the center of the cut-outs and is a straight shot through the holes in BH177.5, the holes in the fin spar, to the control horn). I did some preliminary work using one of the bracket pairs and it appears that it won't be too difficult to allign the brackets to keep the cable loading normal to the pulley attachment bolt. Enlarging the cable pass-thru holes also makes it easier to determine the amount of "bend" in the cable runs at each BH. The cord contacts the hole at the point on the hole diameter that indicates the turn (e.g., 11 o'clock, 5 o'cclock, etc.).
5 Jul 2014 (1 hour, total time to date: 1347.0 hours)
I enlarged the rudder cable pass-thru holes a little more (out to #10) to make it easier to see where the cord was touching the edge of the hole. I assembled one of the pulley/thimble assemblies and started work aligning the assembly on the right side of BH160. It looks like I will need a little more rotation of the assembly than I thought. If so, I'll need to trim the bracket. I'm taking this nice and slow to get it right.
6 Jul 2014 (2 hours, total time to date: 1349.0 hours)
I spent some time aligning/trimming the bracket before realizing that there is a much easier way to solve the problem. The cable is running off axis in 3 directions, so the easiest way for me to determine the proper orientation for the bracket was to remove the BH reinforcement, cut a piece of string, tie a loop around the cord on the flat side of the BH web, and suspend the cord in the center of the pass-thru hole. The string will align itself along the direction of the net reaction to the cable tension. This is the direction that will direct the net cable force directly thru the axis of the pulley. I taped the string to the BH web and then used a piece of blue painters tape to mark the proper alignment direction for the bracket. I should have thought of this sooner......
Anyway, now, I may have to make new brackets since I trimmed a bit more than I really needed, and it looks like I may need more material for sufficient edge distance on the lower, inside bracket. However, I'll wait and see what needs to be done tomorrow, when I look at locations for the bracket attach bolts.
Below is a picture of the method described above to determine the net direction of the cable load due to the change in direction. The string indicates the loading direction for pulley alignment.
Anyway, now, I may have to make new brackets since I trimmed a bit more than I really needed, and it looks like I may need more material for sufficient edge distance on the lower, inside bracket. However, I'll wait and see what needs to be done tomorrow, when I look at locations for the bracket attach bolts.
Below is a picture of the method described above to determine the net direction of the cable load due to the change in direction. The string indicates the loading direction for pulley alignment.
7 Jul 2014 (1 hour, total time to date: 1350.0 hours)
I removed the pulley bracket assembly and extended the cable pass through hole lower so that the cable will not touch the BH. I replaced the pulley assembly & located the position of the tooling hole in the BH web on the bracket. It was too close to the inside edge of the bracket, so I can not use it to attach the assembly. Therefore, I will have make new brackets to provide more space for the attachment bolts.
9 Jul 2014 (1 hour, total time to date: 1351.0 hours)
I was able to salvage the brackets I made for BH160 by removing the pulley/thimble, turning the brackets up side down, & replacing the pulley/thimble. I clamped the bracket on the BH to check the fit and locations of the attachment holes & everything looks fine. The closest attachment hole to the existing tooling hole in the BH web is approx. 3D. I will install two rivets near the top of the pulley reinforcement on each side of the web to secure it so it will also act more like a doubler for the BH web. However, these holes will have to be dimpled so that the brackets will lay flat against the aft side of the BH. I started looking at the brackets and mounting location at BH128.
10 Jul 2014 (1 hour, total time to date: 1352.0 hours)
The cable path I have at BH128 looks to be very straight in the longitudinal/lateral plane, so my method to determine the pulley alignment won't help very much. However, since the direction change here is in the vertical direction only, the pulley orientation will be vertical. I decided to re-fabricate longer brackets to allow the attachment bolts to fit on either side of the BH web flange. I finished making these new brackets.
11 Jul 2014 (1 hour, total time to date: 1353.0 hours)
I needed to fabricate some bushings for the pulley brackets, so I decided to make a tool to help hold the short bushings normal to the disk sander to get nice flat ends on the bushings. I also cut 10 pieces of 0.25 O.D. steel tubing to approximate length (~0.375 in.) and de-burred the edges. The final bushing length needs to be ~0.319.
12 Jul 2014 (3 hours, total time to date: 1356.0 hours)
I used my new "jig" to hold the bushings normal to the sanding disk and sanded each one down to a little over final length and finished them on my scotch brite wheel. They get pretty warm, so I did the sanding in increments and let them air cool. I ended up with 11 bushings (including the one I had already made for the prototype. I then cleaned them up with WD40 and used my air tool to blow out the inside. Finally, I let them sit in some 3 in 1 oil, blotted them "dry" with a clean rag, and put them in a baggy for storage.
I re-assembled the pulley assembly for BH160 and one for the right side on BH128. I want to get things lined up and carefully measured before drilling the attachment pilot holes for the assemblies. I clamped the assembly in place on BH 160 and duct taped the bracket on BH128 (best initial estimate). I clecoed the corner reinforcement in BH128 and ran the cord through the pulleys to check things out. Well, after sighting along the cord, I could see that I was off a bit on my estimate for BH128. I marked the location for the center of the bracket and will make that adjustment tomorrow and take another look.
I re-assembled the pulley assembly for BH160 and one for the right side on BH128. I want to get things lined up and carefully measured before drilling the attachment pilot holes for the assemblies. I clamped the assembly in place on BH 160 and duct taped the bracket on BH128 (best initial estimate). I clecoed the corner reinforcement in BH128 and ran the cord through the pulleys to check things out. Well, after sighting along the cord, I could see that I was off a bit on my estimate for BH128. I marked the location for the center of the bracket and will make that adjustment tomorrow and take another look.
13 Jul 2014 (3 hours, total time to date: 1359.0 hours)
I removed the BH128 corner reinforcement and adjusted the orientation of the pulley bracket assembly. I replaced the reinforcement, ran the cord, and checked the alignment again. I had to repeat the process 3 times before I was satisfied with the alignment. I decided to run of of the actual rudder cables through the pulleys to see if there was any noticeable difference in the location/alignment of the pulley brackets at BH128 & BH160. Everything looked OK. Then, I removed the corner reinforcement and laid out the locations for the AN3 attachment bolts for the pulley brackets. The only real challenge was to be sure that there was sufficient clearance for the upper bolts between the upper flange of the reinforcement and the inside flange on the BH. I traced the location of the BH web on the forward side of the reinforcement and used existing attachment holes to cross-reference the location on the aft side. I also had to allow space for the nut plates that will be attached to the brackets.
14 Jul 2014 (1 hour, total time to date: 1360.0 hours)
I started work locating fastener locations for the outboard side of the pulley bracket at BH160. I want to stay as far from the tooling hole in the BH web as I can and have adequate edge distance for the nut plate rivets in the bracket. I marked the locations, removed the bracket assembly, & drilled the pilot holes in the outside bracket. I then replaced the assembly on the BH, re-aligned it (double & triple checked it), and match drilled the pilot holes through the reinforcement and BH web. I then removed the reinforcement (with the bracket assembly attached), and started work locating the fastener holes for the inboard side of the assembly. The trick here is to allow clearance for the ring doubler rivets, be sure to allow clearance for the AN3 bolt heads and the inside BH web flange, & maintain good edge distance for the nut plate rivets in the pulley bracket.
15 Jul 2014 (1 hour, total time to date: 1361.0 hours)
I back-drilled the pilot attachment hole for the doubler ring hole that interferes with the inboard lower corner of the pulley bracket (to exactly locate this point on the bracket). I then laid out the fastener hole locations to provide the required clearances. I then trimmed/finished the corner of the bracket to clear the doubler ring rivet & drilled the pilot attachment holes through the bracket. I replaced the bracket assembly & match drilled the #40 pilot attachment holes through the reinforcement. I also extended the cable pass through oval hole in the reinforcement and BH web to clear the cable. Finally, I replaced the reinforcement on the BH & ran the cord through the pulleys for the picture shown here.
16 Jul 2014 (1 hour, total time to date: 1362.0 hours)
I assembled the right pulley assembly for BH99.35, used my string method to determine the required pulley orientation, and did a test fit on the aft side of the BH. The cable changes direction both laterally and vertically (somewhat) at this location, so the string method worked for this location. I opened the cable pass though hole to 0.25 in. to provide a little more clearance for the cord (and cable). I trimmed/finished the upper left and lower right corners of the bracket assembly to allow it to be rotated slightly clockwise (looking forward) for alignment. I then laid out the fastener hole locations and replaced the assembly to check for any problems with the hole locations on the BH. Because of the location of a flange notch in BH99.35, I am hesitant to drill a 3/16 in. hole within 5/8 in. of the notch root. It turned out that the lower right edge of the assembly would be a bit close to this notch, and the brackets are too short to accommodate 2 attachment holes (including room for nut plates) if I drill one of them to remain clear of the notch. It appears that the best solution is to drill 2 attachment holes in the left bracket and 1 hole in the right bracket. Since I'm using 2, AN3 bolts for the pulley and thimble, a single bolt on the right side will be sufficient to secure the assembly. I may also bond a doubler around the assembly later to provide a little more material around the bolts since it's conceivable that the brackets may need to be removed/replaced over time.
17 Jul 2014 (2 hours, total time to date: 1364.0 hours)
I removed the right pulley bracket assembly from BH99.35 and drilled #40 pilot holes in the left bracket. I replaced the assembly, clamped it in place, and match drilled the attachment holes through the BH web. Then, I removed the assembly, drilled the pilot hole in the right bracket and match drilled that hole in the BH web. That wraps up the pulley assembly fit up work for the right side. Three pulley assemblies down, and three to go... I then started work on the pulley assembly for the left side of BH160. I assembled the pulley assembly, extended the cable pass through hole, and did the initial fitting/alignment work as I did it for the right side.
18 Jul 2014 (2 hours, total time to date: 1366.0 hours)
Finished the alignment of the left pulley bracket assembly for the left side of BH160, & drilled the attachment pilot holes as was done for the right side. I then removed the pulley assembly & trimmed/finished the edges. I also removed the doubler ring on the forward side of the BH reinforcement to trim/finish the area around the inside lower pulley attachment hole to provide clearance for the AN3 bolt/washer. Finally, I located & drilled a pilot hole between and slightly above the upper pulley attach bolts on each side of the BH web. This will be used to attach the upper portion of the reinforcement to the BH. The pulley bolts will carry any loads in this area, but I wanted to have some attachment in this area to hold the reinforcement to the BH since the pulley assemblies are removable. When finished, access will be limited in the tail cone, and I'd rather have the structure securely connected to minimize the possibility that anything could become trapped between the reinforcement and the BH web if the pulley bolts were removed for maintenance. I was hoping to center the rivets between the brackets, but there was not enough clearance with the inside BH flange. I'll have to use C/S rivets in these holes.
19 Jul 2014 (3 hours, total time to date: 1369.0 hours)
I assembled the bracket assembly for the left side of BH128 and started the fitting/alignment work. Unfortunately, I trimmed too much off of the upper end of the assembly and had to fabricate a new set of brackets and start over. During the alignment process for the right assembly at BH99.35 and again here, I was a little surprised at how accurately the alignment can be determined by simply sighting along the cable at the turning point (even if the turn is slight). The idea is that the cable will appear perfectly straight when looking at it from the direction of the aligned pulley. I used the straight edge of a metal yard stick to sight along the cord and mark the C/L for the pulley assembly. The cord is much easier to use since it doesn't require much force to take out the slack. Anyway, I made a new pulley assembly, finished the alignment work and drilled the pilot attachment holes as I did for the right side. I had to take extra care at this BH because the upper holes of the brackets need to be between the inner BH flange, the upper flange of the corner reinforcements, and allow space for the bolt head (and socket for maintenance).
As a side note, the reason I need pulleys at BH128 is to run the rudder cables under my avionics deck. Without the deck, the cable run could be straight to the pulleys at BH160. Many builders have run them all of the way to the rudder, but that is problematic due to interference with the inner BH flanges and the location of the pass thru holes at BH177.5 as I mentioned in an earlier post.
As a side note, the reason I need pulleys at BH128 is to run the rudder cables under my avionics deck. Without the deck, the cable run could be straight to the pulleys at BH160. Many builders have run them all of the way to the rudder, but that is problematic due to interference with the inner BH flanges and the location of the pass thru holes at BH177.5 as I mentioned in an earlier post.
20 Jul 2014 (2 hours, total time to date: 1371.0 hours)
Finally finished fitting all 6 rudder cable pulley assemblies! I assembled the left pulley assembly and installed it using the same procedure I used for the right assembly. I took a little more time doing the alignment and checking the cable run through the wing carry through BH.
21 Jul 2014 (1 hour, total time to date: 1372.0 hours)
I started work fabricating a reinforcement strip to fit across the upper flanges of the corner reinforcements at BH128. The additional structure is needed to provide sufficient bending strength to support the maximum potential longitudinal load imposed by at the pulleys (due to the cable turning angle). This also requires a connection to the BH web between the reinforcements. I fabricated a 0.040 thick bracket to fit between the reinforcements as well as a strip of 0.040 to be attached to a 0.050 thick cap to stabilize it. The cap will be in compression and must be bent to fit along the corner flanges. I couldn't run the flanges straight across because I need clearance on the C/L to install/remove the elevator push rod. A picture will follow at a later date that should explain this situation.
22 Jul 2014 (1 hour, total time to date: 1373.0 hours)
I cut & bent the 0.050 thick flange reinforcement, and started work fitting it to the corner reinforcements at BH128. I made it wider than needed and will trim it later. I also ran the calculations to verify that the reinforcement will increase the 2nd moment to react the longitudinal load from the cables. The 0.050 reinforcement needs to be at least 1.25 in. wide to handle the maximum bending stress (compression) without local crippling (Ref: Michael Niu, "Airframe Structural Design, Second Edition," p. 135). Therefore, I won't need the additional strip to stabilize the edge of the reinforcement.
23 Jul 2014 (1 hour, total time to date: 1374.0 hours)
I laid out the fastener locations in the bracket that attaches the flange reinforcement to the web of BH128. The 3/16 tooling hole in the web was a bit of an obstacle, but I had enough room for 3 rivets, including a rivet hole in the center of the bracket between the tooling hole and the inner BH flange (0.5 in. above the tooling hole). I clamped the bracket in place on the reinforcement & match drilled the pilot holes through the BH web. I marked the edge of the reinforcement on the upper bracket flange, removed the reinforcement, & laid out 2 rivet locations on the reinforcement. I drilled the pilot holes in the reinforcement, replaced it, and match drilled these holes through the upper bracket flange. Finally, I removed the reinforcement, cleaned up the holes, & trimmed/finished the reinforcement. I cut the reinforcement to 1.375 in. wide and tapered the ends as shown in the photo.
25 Jul 2014 (1 hour, total time to date: 1375.0 hours)
I decided not to install an additional stiffener on the upper flange of the reinforcement running across the web of BH160. The current configuration is adequate to support the bending moment coming from the rudder cable turning angle. So, I removed the reinforcement, marked & drilled pilot holes through the flange (to attach the two existing layers), and replaced the reinforcement. I then started work replacing the bell crank/avionics deck support beams so that I can fabricate/install brackets (shear clips) to transfer shear loads from the beams to BH99.35. I plan to use the same holes through the BH to attach brackets on the forward side for the seat supports that run between BH99.35 and the seat BH. I had to do some trimming/finishing of the forward edge of the right beam top flange to clear the rudder pulley bracket.
26 Jul 2014 (3 hours, total time to date: 1378.0 hours)
I cut 2 pieces of 0.032 thick 2024-T3 (2.375 x 1.875) to fabricate the shear clips. I bent them to provide over an inch on each side to provide a little extra material. I laid the right clip in position & checked to see how much space is available to set the rivets. I then marked and drilled #40 pilot holes approx. 26/32 in. apart in the side that attaches to the web of BH99.35. I then used duct tape to hold the clip in position and match drilled the attachment holes through the BH web. I had to use a long drill bit and flex it to drill the hole as straight as possible. I then removed the clip and marked/drilled the attachment pilot holes for the tail cone beam. I need approx. 1/2 in. clearance to use my Cherry Max puller on these holes - I can see no other way to attach the clip to the beam since the beam can not fit under the rear spar carry through with the clip attached. This will have to be riveted in place after the clip is riveted to the BH. I replaced the right clip & match drilled these holes through the right tail cone beam. I then removed the right tail cone beam & installed the left tail cone beam and repeated the process for the left shear clip. I took my time here, because everything will need to fit together (the beams, avionics deck, & elevator bellcrank housing).The picture shows why I've been so careful about the rudder cable path under the avionics decks.
27 Jul 2014 (3 hours, total time to date: 1381.0 hours)
Now that I have things in the tail cone fitted up, I wanted to get the seat supports fabricated and fit to BH99.35. Once this is done, I can return to the tail cone and get it all buttoned up. It's so much easier to work in this area with the right tail cone skin removed as well as having the center skin spliced. Anyway, I measured and cut out a cardboard template for the seat support to get the fit sorted out. I can see now that the seat support flange was more than likely intended to provide some support for the elevator control torque loading. However, I'm still glad I added the 0.032 thick flanged doubler. The 0.025 seat support may have been just fine, but I like having the additional thickness around the steel stand-off fittings. I had to become a little creative with the flange bending directions for the supports to make the spacing work out well and provide clearance to set some rivets. Once I was happy with the template, I cut out two 0.025 thick aluminum blanks. I trimmed/finished the edges, & made the flange bends for the front & bottom sides of the left support. There is no rear flange because there is no way to install it without removing the seat BH with a rear flange (I opted to turn the seat support flange to the rear to give me clearance for the flap handle). I'll have to use shear clips just like I had to for the tail cone beam (for the same reason). However, this does give me more flexibility for the position of the support at BH99.35 (again, I'll be using the same holes that are used for the forward tail cone beam clips). This work took all of 3 hours because all of the iterations required to get a good fit. I didn't bend the upper flange yet because I want to fabricate the angle bracket for the rear edge of the seat (uses the -5 holes along the rear spar carry thru) and make sure the flange was level with the bracket as well as the seat support flange. Also, I had enough for the day.....
28 Jul 2014 (1 hour, total time to date: 1382.0 hours)
I trimmed/finished the edges for the right seat support and decided to make a spare - just in case. Now that I have the left support fit along the bottom and front/rear sides, I have a much better idea how to trim the right support and I used it to trace the pattern for the spare before bending it. I cut out the spare support and trimmed/finished it as well. I ran out of time for the day, so I'll get back to the bending tomorrow.
29 Jul 2014 (1 hour, total time to date: 1383.0 hours)
I laid out the bend lines & made the bends for the forward/bottom flanges of the right seat support. Then, I cut a piece of 0.032 thick 2024-T3 sheet to fabricate the rear seat support bracket that will attach to BH99.35. I finished the edges & made the bend in the bracket.
30 Jul 2014 (1 hour, total time to date: 1384.0 hours)
I removed the clecos holding the lower web of BH99.35 to the rear spar carry through & positioned/aligned the rear seat support bracket. I clamped the bracket in place with a 1x2 on the outside & used a 5/32 in. duplicating punch to locate the rivet holes. I removed the bracket and drilled #30 pilot holes at the punch marks. I then enlarged the holes to 9/64, and drilled the center hole to #21 & clecoed the bracket in place through that hole. Since it is very difficult to match all 7 holes exactly, I decided to match drill the remaining holes out to #21. Since the holes were already close to final size, it was easy to carefully run a #21 bit through the structure and minimize any damage to the existing holes.
31 July 2014 (1 hour, total time to date: 1385.0 hours)
With the rear seat support bracket in place, I checked the fit of the right & left seat supports. The supports needed additional timming to properly fit under the bracket flange. I trimmed/finished the rear edges of both supports until they fit nicely under the rear support bracket. I started work aligning the supports for final fitting on the bottom center section skin.
1 Aug 2014 (1 hour, total time to date: 1386.0 hours)
I laid out the fastener holes along the bottom flanges of the right & left seat supports. I used a hole spacing of approx. 1.5 inches to match the spacing used for the seat support BH. I then punched 3/32 pilot holes in the flanges with my Whitney punch. I de-burred the holes & replaced the supports in the center section. I double checked the alignment of the supports, duct taped them in place, & match drilled #41 pilot holes through the flanges.
2 Aug 2014 (2 hours, total time to date: 1388.0 hours)
I laid a straight edge on top of the BH flanges between the seat BH & BH99.35 to mark the bend line for the upper flanges on each seat support. I removed each support & clamped 1x2s on each side of the support along the bend line. I placed the clamped-up assembly in a bench vise & used a hard rubber mallet and a piece of oak to form the flanges. I used the 1x2 piece of oak that I had fabricated to bend the tail cone beam on the forming side since the edge was rounded and tapered to allow the bend to go beyond 90 degrees (~5 degrees) to allow for spring-back. After the bending, I still needed to adjust the bends slightly with my flanging pliers. After all of the trimming/finishing I've done on these parts, I still needed to do a little more trimming/finishing around the ends to provide clearance for the flanges and a little more stress relief at the bend radii.
3 Aug 2014 (3 hours, total time to date: 1391.0 hours)
I removed the left & right seat supports to mark/drill the pilot attachment holes in the front flanges to attach them to the seat BH. I replaced the supports & match drilled the pilot holes through the seat BH using a long drill bit from the aft side. To get better access to the top holes, I removed the seat BH (with the supports attached) & match drilled these holes. Once completed, the entire assembly can be riveted together since it can be installed as a unit. However, I will not drill out the attachment holes to the bottom skin until the assembly is complete (in case of any movement during riveting). Then, I replaced the assembly and started work fabricating/installing the attachment brackets (shear clips) between BH99.35 and each seat support. I cut out the blanks, finished the edges, & bent them with my bench top brake. I positioned each one, clamped them to the seat support, used duct tape to hold them against the BH flange, & match drilled the attachment holes to the BH from the back side of the BH. Again, I used the same holes through the BH as are used to attach the brackets for the forward end of the tail cone beam. Once these holes were drilled, I removed each bracket, located the attachment holes to the seat supports, & drilled these pilot holes in the brackets. Then, I replaced the brackets, marked the hole locations with a sharpy through the pilot holes in the brackets, duct taped/clamped them to the supports, & removed the entire assembly once again to match drill these holes (there was no room to get a drill between the supports). I removed each support from the seat BH & match drilled the bracket attachment holes. I then trimmed/finished the brackets, assembled the structure, & replaced it in the center section to be sure everything fit.
4 Aug 2014 (1 hour, total time to date: 1392.0 hours)
Now that the basic fit-up work in the tail cone is complete, I started preparing the rudder pulley support structure for final assembly. I removed the support structure from BH160 & drilled out the doubler attachment holes for the race track cut-out to #30. Then, I took the assembly apart, trimmed, & lightly finished the edges to provide clearance for the tail cone skin. It took a few iterations to get the fit I wanted. I then replaced the structure and checked the effect of the attachment on the position of the skin flange. The pulley support stiffens up the BH substantially, & I wanted to be sure that I won't have any problems replacing the skin. I will probably use some kind of support to hold the right side of the BH flange as close as possible to the final position when I drill out the attachment holes to the BH web.
5 Aug 2014 (2 hours, total time to date: 1394.0 hours)
I continued working on the rudder pulley support structure at BH160. I took the ruddey pulley assemblies apart to double check the fit of the bushing and to be sure that the attachment holes will line up again when re-assembled. Everything looked very good when re-assembled and clecoed back in place. I then drilled out the bracket attachment holes to 1/8, removed the brackets, replaced the support structure on the BH, & match drilled the attachment holes out to 1/8 in. Then, I removed the support structure again, took the assembly apart, removed the protective plastic, & spent the rest of the time doing finishing work on the holes & edges.
6 Aug 2014 (2 hours, total time to date: 1396.0 hours)
I decided to add a 0.040 thick doubler between the pulley brackets nested inside the upper flange. This will increase the bending strength between the BH webs. I may not need it, but the weight penalty is very low & now would be the time to do it (if ever). I want to be sure that this structure will provide a very stable platform for the pulley brackets and would not want to have to make a repair later. I made a cardboard template to fit between the brackets and nest under the upper flange. I then cut out the blank & bent it to fit. I spent some time trimming/finishing the edges, clamped the doubler in place, & match drilled the #40 pilot attachment holes through the upper flange.
7 Aug 2014 (1 hour, total time to date: 1397.0 hours)
I used a duplicating punch to mark the location of the attachment holes in the new doubler along the upper portion of the elevator pass through hole. I then drilled 1/8 in. holes at these locations using a nibbed drill bit (worked like a charm!). Then, I assembled the parts & match drilled these holes out to #30 in preparation to finish the assembly. Finally, I did more finishing work on the parts.
Two more attachment holes are needed through the new doubler below the flange bend.
Two more attachment holes are needed through the new doubler below the flange bend.
8 Aug 2014 (1 hour, total time to date: 1398.0 hours)
I located two additional attachment holes below the upper flange on the new doubler, drilled #40 pilot holes in the doubler, assembled the parts, & match drilled the holes out to #30. While I had the new doubler off, I also rounded the ends of the doubler to approx. 3/8 in. radius around the attachment holes. I then replaced the support on the BH and match drilled the holes through the web out to #30 (except for the hole above the cable pulley which will be dimpled - I think it works better to dimple 1/8 in. holes so that the expansion will keep the final hole size closer to #30).
9 Aug 2014 (2 hours, total time to date: 1400.0 hours)
I removed the support (again) to drill the rudder pulley bracket attachment holes out to #12 for the AN3 attach bolts. I may have been able to do this in one step, but I generally prefer to do it in steps to keep the hole quality as nice as possible. It also makes it easier to match drill the holes through the BH web. I did this in 3 steps - #21, #19, & #12. The nice thing is that 5/32 clecos work fine in the #21 and #19 holes. Once the #12 holes were drilled, I installed AN3 bolts to hold the brackets in place as each hole was drilled. At each step, I had to replace the assembly and match drill the holes through the BH web. I had to drill them from the front side (web first) because I couldn't get a straight shot through the holes on the left side since the tail cone is tapered - again, the other very good reason to do this in smaller steps. It took some time, but it turned out well.
10 Aug 2014 (3 hours, total time to date: 1403.0 hours)
I removed the pulley bracket support assembly and took it apart to go over the holes and edges again. Troy Grover (GrovAir) called it "building character." I dimpled the holes above the cable pass-thru holes in the 2 layers of the support structure. To dimple the corresponding holes in the web of BH160, I attached the dimpling mandrel to my rivet gun with the female die on the gun and the male die inserted in the hole I had drilled on one of my tungsten bucking bars. I lower the pressure down to around 30-35 psi, and it seems to work pretty well on the 0.032 thick parts. Then, it was time to prepare the pulley brackets for etch/alodine. I took them apart and placed the hardware in two baggies (left & right), did a little more finishing work, tied string to each part to keep track of which is which (red for left and blue for right - I don't have green), degreased, etched, and alodined each part. I see a little nick that I missed on the edge of the part on the left - I'll touch that up later.....
11 Aug 2014 (1 hour, total time to date: 1404.0 hours)
I cut an AN3-4 bolt short and cleaned up the remaining threads so that I could use it to line up the nut plates on the brackets to match drill the nut plate attach holes. I drilled out all of the nut plate holes on the aft pulley brackets & de-burred them. Then, I degreased the brackets & applied a light coat of primer on the nut plate side.
12 Aug 2014 (1 hour, total time to date: 1405.0 hours)
I installed the nut plates on the aft pulley brackets with my pneumatic squeezer using NAS1097-3-3.5 rivets. Hopefully, the AN3-10 drilled bolts will arrive tomorrow & I will prepare to re-assemble the brackets.
Also, I'm very happy to note that I ordered my engine today. Jasson (my friend and IA) noticed it on the net, and texted me about it. I called, got copies of the log book, Jasson also took a look, & I pulled the trigger. It's a 2010 Continental O-200D with 263 hours. The warranty (30 days) begins at first flight. I'll be posting pictures when it arrives.
Also, I'm very happy to note that I ordered my engine today. Jasson (my friend and IA) noticed it on the net, and texted me about it. I called, got copies of the log book, Jasson also took a look, & I pulled the trigger. It's a 2010 Continental O-200D with 263 hours. The warranty (30 days) begins at first flight. I'll be posting pictures when it arrives.
13 Aug 2014 (1 hour, total time to date: 1406.0 hours)
I de-greased & primed the outside of the aft pulley brackets in preparation to be assembled & mounted on the support structure. I also decided to add two more attachment holes on the support structure - along the lower portion of the inside doubler, between the BH webs. I measured the location to ensure that there was sufficient clearance from the webs and the ring doubler, as well as adequate fastener spacing. I drilled the #40 pilot holes, then enlarged them to 1/8, then to #30. I took the assembly apart and de-burred the holes. I re-assembled the structure & replaced it on BH160.
15 Aug 2014 (1.5 hours, total time to date: 1407.5 hours)
I assembled the aft pulley brackets and temporarily secured the castle nuts with cotter pins (I'll safety wire them before final installation - my wire twister is at the airport). It took a little while to get the nuts adjusted to allow the pulleys to move smoothly. I then cut 4 AN3 bolts short to use them to temporarily attach the brackets (two on the diagonal for each), but not go all of the way through the nut plates. It probably wouldn't make much difference, but I didn't want to loosen the nuts before final installation.
16 Aug 2014 (1.5 hours, total time to date: 1409.0 hours)
Before finishing/assembling the aft pulley support structure, I wanted to check the rudder cable path one more time to be certain that the cable will not make any contact with the edges of the pass-thru holes. I ran a cord through the pulley run and tightened it to see how it fit through the aft pass-thru holes on each side. I marked the edges where it was a little close & used my Dremel 1/4 inch sanding drum to clean up the holes. I then removed the structure & did more finishing work to the edges.
17 Aug 2014 (3 hours, total time to date: 1412.0 hours)
I took the pulley support structure apart and went over everything one last time prior to final assembly. I de-greased, etched, & alodined the parts. Then, I applied a light coat of primer on the mating surfaces. When the primer had dried, I started work riveting the structure together.
18 Aug 2014 (2 hours, total time to date: 1414.0 hours)
I finished riveting the assembly together & clecoed it back in place on BH160.
Next, I will get back to work on the skin stiffeners that I'm adding between BH160 & 177.5. The right skin had a "ripple" in that area and I thought it wouldn't be a bad idea to have a stiffener above the access panel. Jasson and Tim will be coming over soon to take a look at the new engine, and will be able to help me set some rivets that I can't do by myself.
Next, I will get back to work on the skin stiffeners that I'm adding between BH160 & 177.5. The right skin had a "ripple" in that area and I thought it wouldn't be a bad idea to have a stiffener above the access panel. Jasson and Tim will be coming over soon to take a look at the new engine, and will be able to help me set some rivets that I can't do by myself.
19 Aug 2014 (1 hour, total time to date: 1415.0 hours)
I cut a piece of 0.032 2024-T3 to size (approx. 1.25 x 17 in.), finished the edges, and bent it to form a skin stiffener to fit above the aft access panel. I then measured and laid out the fastener pattern with a 1 inch rivet spacing.
20 Aug 2014 (1 hour, total time to date: 1416.0 hours)
I punched 3/32 pilot attachment holes in the new, left skin stiffener, & marked the location for the stiffener on the tail cone. I then taped the stiffener (upside down) on the outside of the skin along the attachment line, & match drilled the attachment holes on each end of the stiffener. I then removed the tape, turned the stiffener right side up, clecoed it on the inside of the tail cone, & finished drilling out the pilot holes along the stiffener. I then drilled them all out to 1/8 in., removed the stiffener, & de-burred the holes in the skin and stiffener.
The big news for the day is that my engine arrived!
The big news for the day is that my engine arrived!
21 Aug 2014 (1 hour, total time to date: 1417.0 hours)
I dimpled the attachment holes in each aft skin stiffener with my C-frame dimpler. I dimpled the holes in the skin using my rivet gun set at low pressure (~25 - 30 psi) with the opposite die in one of my tungsten bucking bars. I also spent a little time buffing out the die marks in the parts with a scotch brite pad.
22 Aug 2014 (2 hours, total time to date: 1419.0 hours)
I taped off the area around the aft skin stiffeners for priming & removed the stiffeners for de-greasing, acid etch, & alodine. I also drilled out all of the attachment holes in the new doubler for BH177.5 & removed it for finishing. While I was at it, I realized that I hadn't alodined the reinforcement for the left stabilizer attachment hole at BH160, so I removed it as well. I went over all of the removed parts and did some final finishing work with scotch brite. I de-greased the parts as well as the mating surfaces of the skin & web of BH160. I applied a light coat of primer on the skin and BH web. I then etched & alodined the stiffeners, doubler, & stabilizer attachment reinforcement.
23 Aug 2014 (1 hour, total time to date: 1420.0 hours)
I applied a light coat of prime to the mating surfaces of the parts I alodined yesterday & replaced them on the airplane. I decided to work on the aft inspection panel to get it finished and ready to install. I dimpled the doubler attachment holes & clecoed it in place. I clecoed the inspection cover in place and match drilled those attachment holes out to #19 in two steps - first to #21. I'm using #8 machine screws for the inspection covers. Finally, I marked the inside of the cover for orientation, removed the plastic from the cover, & de-burred the holes and edges.
24 Aug 2014 (3 hours, total time to date: 1423.0 hours)
I dimpled the aft inspection cover attachment holes as well as the corresponding holes in the doubler plate. I then started work building a framework to support the new engine since Jasson is planning to come over tomorrow evening to take a look at it. I have the damaged firewall that can be used to locate the engine mount holes and serve as a template for the firewall on the airplane once I drill out pass-thru holes to route wiring, etc. I laid out 2x4's under the old firewall and drilled attachment holes along the same lines as used on the airplane to provide shear stability. I de-burred these holes, marked, and match drilled the 3/8 in. engine mount attach holes.
25 Aug 2014 (1 hour, total time to date: 1424.0 hours)
I attached the damaged firewall to the 2x4s using #6 screws & attached a 2x4 across the top of the assembly to stabilize the assembly & provide attachment points for 2x4 braces to hold the assembly vertically. I also screwed 2, 6.5 in. 2x4 blocks to a work table to attach the bottom edge of the assembly.
26 Aug 2014 (2 hours, total time to date: 1426.0 hours)
I leveled the engine support assembly by sanding the ends of the vertical supports & attached them to the blocks on the work table. I then used 2x4 in. steel straps to reinforce the back of the assembly at the intersection of the 2x4 wood frame. Because of the location of the engine mount holes in the upper portion of the assembly, I drilled 3/8 in. holes in the straps. This will work well to support the wood in this area since these bolts will be in tension. I attached the straps using 1 inch #8 wood screws. Finally, I temporarily braced the assembly vertically & placed the engine mount on the assembly. I checked the clearance required for braces to support the weight of the engine.
27 Aug 2014 (1 hour, total time to date: 1427.0 hours)
I checked the location of the cylinders (and intake manifolds) in relation to clearance issues for the 2x4 supports on each side of the engine mount. I have to keep the side supports as close as possible to the assembly and the further I can extend them forward, the better it will be for stability of the assembly. I am quite limited by the location of the cylinders and intake manifolds. I want to avoid taking up more work table space by attaching supports behind the engine. I cut the support 2x4s to fit the upper cross member and rest flat on the table on either end. The left support can extend further forward, so I took advantage of it - the supports are not symmetrical. I checked the loads, and everything looks OK.
29 Aug 2014 (1 hour, total time to date: 1428.0 hours)
Continued working on the engine support structure. I cut & attached a second 2x4 across the top of the frame so that I can tie the upper ends of the sides support to it. I also cut the left side support to fit.
30 Aug 2014 (2 hours, total time to date: 1430.0 hours)
I cut the right side support & sanded both supports to fit properly. I clamped the supports to the top of the frame & toe screwed the bottoms of the supports to the work table. I then cut 2 pieces of 1x2 to attach along the side of each support on the work table, clamped them to the supports, & screwed them to the table. Then, I drilled a pilot hole in each side for 1/4 in. lag screws to firmly attach the bottom of each side support to the 1x2s. I decided to replace the wood screws I had on the steel doublers on the support frame with #8 lathe screws (much better). Finally, I attached the engine mount to the support structure with 3/8 bolts.
31 Aug 2014 (3 hours, total time to date: 1433.0 hours)
I assembled an engine hoist from Harbor Freight so that I can mount the engine on the support for storage. Dick Holsworth came over to help me get the engine off of the pallet and on the hoist. I was fortunate to be able to get serviceable isolation mounts from Wentworth Aircraft. Unfortunately, when Dick and I tried to bolt the engine in place, we discovered that the mounting bolts were too short. Dick had to leave, so I went out and found some grade 8 bolts that would fit - at least good enough for now. I then, wrestled the engine in place. Actually, at one point, Beth came out to the garage, and I asked her to help hold one of the mounts in place while I got the bolts in one side :-).
1 Sep 2014 (1 hour, total time to date: 1434.0 hours)
I cut the quick drain tube on the oil tank shorter because it was resting on the table top and the engine had settled enough that oil was leaking onto the table. It extended too far anyway and would have been well below the bottom of the airplane. I then resumed work drilling the nut plate attachment holes on the aft tail cone access plate doubler. I finished all of the holes in the aft doubler.
2 Sep 2014 (1 hour, total time to date: 1435.0 hours)
I drilled the nut plate attachment holes in the forward tail cone inspection plate doubler, de-burred the holes, & did more finishing work on the parts.
3 Sep 2014 (1 hour, total time to date: 1436.0 hours)
I de-greased, etched, & alodined the access panels & doublers. I also de-greased and applied a light coat of primer inside the tail cone around the access panel doubler mating surfaces.
4 Sep 2014 (1 hour, total time to date: 1437.0 hours)
I lightly primed the access panel doublers and started work installing nut plates on the forward tail cone doubler.
5 Sep 2014 (2 hours, total time to date: 1439.0 hours)
Finished installing the nut plates on the forward tail cone doubler & started installing nutplates on the aft access panel doubler. Jasson came over and helped me rivet the doubler on BH177.5 as well as the rudder pulley support on BH160.
6 Sep 2014 (2.5 hours, total time to date: 1441.5 hours)
Finished installing the nut plates on the aft access panel doubler and clecoed both doublers on the tail cone. I cut a few more #8 machine screws short to temporarily attach the covers to the doublers (just to keep things all together). I then started work to drill out the fastener holes on the pulley support structure at BH128. Part of that process was to enlarge the attachment holes in the pulley brackets out to #12 in steps. I also discovered that the rivet tails for two fasteners along the top of the support will touch the pulley brackets. Therefore, I had to trim the brackets slightly to provide more clearance in these areas.
7 Sep 2014 (1.5 hours, total time to date: 1443.0 hours)
To preserve my new engine while I'm working on the airplane, I needed to spray preservative oil inside the cylinders. I also needed to be able to turn the crank to move the pistons during the process. I fabricated a lever from a piece of 3/4 inch hardwood plywood to bolt on the hub. It worked fine and I was able to turn the crank with it. However, a spray bottle didn't work at all - just squirted a stream of oil. I bought a cheap paint spray gun and used it instead. The spray gun worked very well - put out a nice fine oil "mist."
11 Sep 2014 (1 hour, total time to date: 1440.0 hours)
A little building interruption due to a business trip, but I'm now back to work. I resumed work drilling out the attachment holes for the pulley support structure on BH128. I also drilled out the pulley bracket attachment holes to #19, but will wait to finish them at #12 until I take them apart to replace the temporary bolts with drilled bolts with cotter pins. I replaced the tail cone beams to attach the rear shear clips so that everything was held in position while I drilled out the holes in the rear shear clips to 1/8 in.
It looks like the best assembly sequence will be to rivet the upper flange to the pulley support, replace the assembly, & rivet the tail cone beam shear clips in place as I rivet the support to BH128. Then, the forward tail cone beam shear clips can be riveted to the beams. Each beam can be replaced in the tail cone, & the rear shear clips can be attached using Cherry Max rivets. The forward clips will have to wait until BH99.35 has been removed for deburr/dimpling and replaced.
It looks like the best assembly sequence will be to rivet the upper flange to the pulley support, replace the assembly, & rivet the tail cone beam shear clips in place as I rivet the support to BH128. Then, the forward tail cone beam shear clips can be riveted to the beams. Each beam can be replaced in the tail cone, & the rear shear clips can be attached using Cherry Max rivets. The forward clips will have to wait until BH99.35 has been removed for deburr/dimpling and replaced.
12 Sep 2014 (1 hour, total time to date: 1441.0 hours)
I continued work to drill out the attachment holes for the tail cone beams. I replaced the elevator bellcrank housing between the beams, drilled out the pilot attachment holes along the beam to #31, & finished them to 1/8 in. The holes through the 0.062 thick angles that form the base of the bellcrank housing needed to be drilled out to 1/8 to allow clecos to be installed. The holes in the skin and beams will be dimpled, so the 1/8 diameter will work nicely, but I will need to open the holes in the base of the housing to #30 prior to C/S.
13 Sep 2014 (4 hours, total time to date: 1445.0 hours)
I finished drilling out the pully bracket attach holes to #12 at BH128. Then, I removed the plastic from the pulley support structure & deburred/finished the edges. I then replaced the structure to drill out the holes to the final size (#30). I removed the pieces yet again & did more finishing work to get them ready for alodine. finally, I drilled out the attachment holes for the shear clip/tail cone beam attachments & deburred/finished the clips. It seems like a lot of time, but the finishing work is a pretty good time sink.
14 Sep 2014 (2 hours, total time to date: 1447.0 hours)
I drilled out the #40 nut plate holes for the pulley brackets. Since I don't have a nut plate drilling template, I just cut a AN3 bolt short so it was pretty easy to almost hand tighten the bolt to hold the nut plate in position. Once they are in position, it is easy to match drill the attachment holes. After the first hole is drilled, I just used a cleco (or rivet) to keep the plate from moving while I drilled the second hole. I took the 2 pulley brackets apart, tagged, and bagged the internal pulley bracket parts to keep track of what goes with each bracket. Then, I de-greased, etched, and alodined the pieces. Once they were dry, I applied a light coat of primer to the mating surfaces of the parts.
15 Sep 2014 (1 hour, total time to date: 1448.0 hours)
I riveted #10 nut plates to the pulley brackets, degreased the back of each bracket, & applied a light coat of primer to the back of each one.
16 Sep 2014 (1.5 hours, total time to date: 1449.5 hours)
I re-assembled the pulleys & installed cotter pins in the bolts. I decided to stick with the cotter pins after seeing how well they stay in when I was trying to remove them when I was preparing to alodine the parts. Then, I riveted the pulley support pieces together for installation on BH128.
17 Sep 2014 (1.5 hours, total time to date: 1451.0 hours)
I degreased and applied a light coat of primer to the mating surface of BH128 and the pulley support bracket. While that was drying, I installed the permanent AN3 bolts for the pulley brackets at BH160. I had to trim the ends of 2 bolts to provide clearance with the pulley nuts. I also used different bolt lengths and washer combinations to be sure that the threads extended through the pulley brackets, yet did not bottom out in the nut plates. After installing the nuts, I checked to see if the pulleys would turn easily with the rudder cable. Although the pulleys appeard to rotate easily by hand, they did not turn with the cable. I removed the cotter pins from the castellated nuts on the left side and made some adjustments until the pulleys would turn nicely with the cable. I found that when the pulley bolts would just turn easily by hand, then the pulleys would also rotate with the cable travel. I did not want the bolts to be too loose, but also did not want the cables to cut into the phenolic. This took more time than I expected, but I think it was time well spent. I will work on the other pulleys tomorrow.
18 Sep 2014 (1 hour, total time to date: 1452.0 hours)
I pulled the cotter pins out of the remaining 3 finished rudder cable pulleys and adjusted the nuts to allow the pulleys to rotate more freely, and replaced them on the structure.
20 Sep 2014 (4 hours, total time to date: 1455.0 hours)
I de-burred/finished the attachment holes for the tail cone beams (in the tail cone and on the beams). This always takes more time than I expect. Once that was done, I dimpled the holes in the tail cone beams. Then, I dimpled a hole in a small piece of scrap 0.04o thick sheet to use as a guide to C/S the holes in the elevator bell crank housing. I C/S these holes so that the housing will be ready for installation once Jasson comes over and helps me dimple the attachment holes in the tail cone bottom skin. Finally, I started work drilling out the holding rivets along the left side of BH99.35. Once I have the holes in BH99.35 ready, I will need to support the tail cone so I can remove the BH for de-burring, finishing, and dimpling.
21 Sep 2014 (1 hour, total time to date: 1456.0 hours)
I de-burred the attachment holes for the shear clips on the forward ends of the tail cone beams. I did more finishing work on the clips. Finally, de-greased, etched, & alondined the clips.
22 Sep 2014 (1 hour, total time to date: 1457.0 hours)
I primed the mating surfaces of the shear clips and tail cone beams. When that had cured, I started work riveting the clips to the tail cone beams. It was a bit difficult to access the rivets in this location because of the size of the flanges. I ended up having to drill out the lower rivets and re-install them. The upper rivets are even more difficult, and I will have to trim the corners of the down turned flange on each beam to be able to use my squeezer on these rivets.
23 Sep 2014 (1 hour, total time to date: 1458.0 hours)
I trimmed/finished the corners of the tail cone beam flanges (noted yesterday) to allow me to install the upper shear clip rivets on the forward edge of each tail cone beam. I installed the rivets & touched up the primer on the beams.
29 Sep 2014 (1 hour, total time to date: 1459.0 hours)
I had to take a little time off again, but am finally able to get back to work. My daughter, Amanda, is home for a little while and agreed to help me dimple the tail cone beam attachment holes in the tail cone skin using my rivet gun. She opted to use the gun, while I used a tungsten bucking bar to support the male dimpling die under the skin. It didn't take too long to get those holes dimpled, and I spent the rest of the hour drilling out the attachment holes along the upper left side of BH99.35 out to 1/8 in.
30 Sep 2014 (1 hour total time to date: 1460.0 hours)
I replaced the tail cone beams, elevator bellcrank, and avionics decks in the tail cone. I started work drilling out the attachment holes for the avionics decks and upper bellcrank support. I drilled them all out to 1/8 inch.
1 Oct 2014 (1 hour, total time to date: 1461.0 hours)
I finished drilling out the avionics deck & bellcrank support attachment holes to #19 in 2 steps starting with #21. Then, I removed the pieces and will deburr and dimple the holes tomorrow.
2 Oct 2014 (1 hour, total time to date: 1462.0 hours)
I deburred all of the attachment holes for the avionics deck and upper elevator bellcrack supports. Then, I dimpled the holes for #8 C/S machine screws.
3 Oct 2014 (1 hour, total time to date: 1463.0 hours)
Drilled out the nut plate attach holes in the angle support for the avionics decks. I cut another C/S #8 screw short to hold the nut plate in position while I match drilled the holes. For the nut plate in the tail cone beams, this would not work since I already had the holes dimpled and there was not enough room under the flange to match drill from that side. So, I cut a piece of 0.032, drilled & dimpled a #19 hole, match drilled nut plate holes, & used it as a template to match drill the holes from the top side of the beam flanges. I had to make 2 of these templates since the holes became unusable after drilling out the holes in one of the beams.
4 Oct 2014 (5 hours, total time to date: 1468.0 hours)
Jasson came over this morning and helped me set the rivets for the pulley support structure at BH128. We installed the rivets for the left aft tail cone stiffener. I de-greased & primed the lower tail cone skin around the mating surfaces of the tail cone beams. Then, we installed the nut plates in the tail cone beams & riveted the beams in place. We didn't install the rivets where the bell crank housing would be since I have to do a little more work on the housing. After Jasson left, I applied some primer to the bottom of the housing and some engine enamel to the mating surfaces where the nut plate will be. When that dried, I installed the nut plates on the upper flanges of the housing.
11 Oct 2014 (1.5 hours, total time to date: 1469.5 hours)
I ordered 4 exhaust flanges from A/C Spruce to help seal the exhaust manifold for storage. I installed 3 of them, but the 4th was the wrong flange, so I will have to order a replacement. I drilled out the attachment holes to 1/8 in. for the avionics deck supports along the sides of the tail cone skins. I removed th supports, de-burred/finished the parts, & dimpled all of the holes.
12 Oct 2014 (2.5 hours, total time to date: 1472.0 hours)
I did a little more finishing work on the avionics deck supports and the upper supports for the elevator bellcrank housing. Then, I de-greased, etched, & alodined these parts. Once dry, I de-greased the mating surfaces of the tail cone skin & primed this area as well as the mating surfaces of the avionics deck supports. When the primer had cured, I installed nut plates on the deck supports.
13 Oct 2014 (2 hours, total time to date: 1474.0 hours)
I de-greased and primed the upper supports for the elevator bellcrank housing, clecoed the deck supports in the tail cone. I also de-greased the tail cone beams and skin where the bellcrank housing will be mounted. I primed this area & replaced the housing as well as the decks and upper supports. Then, I replaced the left center skin & match drilled the attachment holes along BH99.35 out to 1/8 in. I removed this skin and replaced the right tail cone skin to drill out all of the holes around the upper portion of BH99.35 to 1/8 in. I decided to use all of the pilot holes in the flange tabs. Finally, I drilled out the holding rivet on the right center skin doubler at BH99.35.
14 Oct 2014 (1 hour, total time to date: 1475.0 hours)
I drilled out two holding rivets between the bottom tail cone skin and BH99.35 near the rear spar carry through on each side. I had to use a long drill bit since the vertical jig supports for the carry through were in the way. I replaced the left center skin (again) to match drill all of the holes between the center skin along the flange of BH99.35 to 1/8 in. I removed the left skin, did some light de-burring, & clecoed the right center skin in place to repeat this process on the right side tomorrow.
15 Oct 2014 (1 hour, total time to date: 1476.0 hours)
I match drilled all of the attachment holes along the right side of the center skin along BH99.35 to 1/8 in., removed the skin, & did some light de-burring. I also drilled out the attachment holes between the left tail cone skin and the left longeron to 1/8 in. in 2 steps. Mikey can be seen here inspecting the airframe.
17 Oct 2014 (1.5 hours, total time to date: 1477.5 hours)
I drilled out the 1097-3 holding rivets between the center bottom skin and the splice doublers on each side of the airframe. Once that was finished, I removed the center bottom skin to gain access to the holding rivets along the bottom flange of BH99.35. These holding rivets need to be removed so that all of the fastener holes around the flange of the BH can be drilled out to 1/8 in. for dimpling.
Also, I had an electric heater installed in the garage since it was so cold out there last winter. The new heater required a 220V/30A circuit and puts out approx. 19K BTU.
Also, I had an electric heater installed in the garage since it was so cold out there last winter. The new heater required a 220V/30A circuit and puts out approx. 19K BTU.
18 Oct 2014 (3.5 hours. total time to date: 1481.0 hours)
Jasson came over to help me rivet the right aft tail cone stiffener, both side avionics deck supports, & the elevator bellcrank housing. He also drilled out the 1097-3 holding rivets along the bottom flange of BH99.35, and helped me replace the center bottom tail cone skin. After Jasson left, I match drilled the fastener holes around the bottom flange out to 1/8 in.
25 Oct 2014 (1 hour, total time to date: 1482.0 hours)
OK, after being out of town, I'm now getting back to work. Aircraft Spruce shipped me another exhaust flange to replace the one they had sent that was the wrong size. I de-burred the edges of the flange & installed it to seal the last exhaust port on the engine. Then, I started work making a prototype of the skin splice at BH99.35. I want to see how the standard #30 dimples nest for the BH flange & the center/tail cone skins. When you nest two dimpled skins, there is a gap between the skins that is a function of the countersink angle and the thickness of the top skin. For a 100 degree C/S and a 0.032 top skin, the gap will be: 0.032/sin(50)-0.032, or approx. 0.098 in. This gap is normally taken care of by the riveting process, where the gap is closed by the riveting force and the rivet holds the pieces together. For 3 layers, I want to check to see how the process will work. The other concern I have is for the center skin splice doubler, since it will make the 4th layer at two fastener locations at the BH flange on each side. I know I can use a deeper die for the inside flange, but I want to see what happens if I don't.
I fabricated the prototype flange/tail cone skin/center skin specimen, finished the edges, drilled the holes out to 1/8 inch, & de-burred the holes.
I fabricated the prototype flange/tail cone skin/center skin specimen, finished the edges, drilled the holes out to 1/8 inch, & de-burred the holes.
26 Oct 2014 (2.5 hours, total time to date: 1484.5 hours)
I dimpled the holes, assembled the parts, & riveted them together. The riveting process did not close the gaps as I had hoped, and resulted in buckled/wavy skin between the rivets. I do not want this, so I looked for deeper dimpling dies on-line. All I could find were for 3/32 rivets, so I decided to make another prototype and try "re-dimpling" the stack prior to riveting. I've also read about using a de-burring tool on the lower sheets, but I hate to thin the material - especially in this case with the 0.025 thick tail cone skin under the 0.032 center skin.
I made another prototype (#2), dimpled the holes, assembled the parts, used my squeezer to press the dimple die into the stack. This appeared to close the gap and the upper skin was flush. I installed the rivets and got a much better result. I don't think I want to try this for the holes into the 0.040 thick splice doubler, so I'll use universal head rivets at those holes. Also, I'll use universals along the flange line at BH73.75 since my extra doubler adds a 4th layer along the flange.
I made another prototype (#2), dimpled the holes, assembled the parts, used my squeezer to press the dimple die into the stack. This appeared to close the gap and the upper skin was flush. I installed the rivets and got a much better result. I don't think I want to try this for the holes into the 0.040 thick splice doubler, so I'll use universal head rivets at those holes. Also, I'll use universals along the flange line at BH73.75 since my extra doubler adds a 4th layer along the flange.
27 Nov 2014 (1.5 hours, total time to date: 1486.0 hours)
Although using a dimple die set to force the stack to lay flush prior to riveting seems to work well, I thought I'd see what would happen if I dimpled each layer starting from the top and worked my way through the stack by adding each layer in turn. I fabricated 3 spacers from 0.032 and 0.025 sheet, dimpled the 0.032 spacers, dimpled the 0.025 spacers with the 0.032 spacers, then, I dimpled one hole in a piece of 0.032 with both spacers in the die. This seemed to work, but I noticed that the dimple in the base sheet wasn't noticeably deeper (a 426 rivet head appeared to be nearly flush with the surface. The hole was a bit more rounded - which would explain why the spacers would sit flat. I then decided to try another hole in the base sheet, but dimple it first with the standard die, then squeeze it again with two spacers (0.032 & 0.025 as would happen at the splice joint at BH99.35). This was essentially the same procedure that I used on the 2nd prototype shown above. The second hole (the lower hole in the photo) was deeper - a rivet head was clearly below the surface. I think this hole looks better as well, but the final test will be to cut through both holes after riveting and look at the cross section. I'll do that tomorrow.
28 Oct 2014 (1 hour, total time to date: 1487.0 hours)
I inserted rivets in each hole in the prototype to show that the second hole was deeper - dimpled first with the standard die, then dimpled again with the stack to be riveted. I then riveted the spacer stack at each hole, cut across the hole, and polished the cut surface to take a look at the results. It was very difficult to get a good photo with my cell phone camera because of a depth of field issue. I got one decent picture of the second hole (shown here), but I really couldn't see any real difference in the way the rivet filled either hole. However, I think the rivet head set better in the second hole. Therefore, I will use this method from this point forward. If I could find deeper dies for 1/8 inch rivets, I'd consider using them, but they aren't currently available to me.
31 Oct 2014 (3 hours, total time to date: 1490.0 hours)
Happy Halloween! Jasson is coming over tomorrow to help me attach the right tail cone skin, so I needed to finish a few more things before it will be difficult to work inside the tail cone. I installed 2 Cherry Max rivets on each shear clip at BH128. These attach the tail cone beams to the BH. Then, I installed the permanent AN3 bolts at each pulley support bracket. The right bracket was no problem, but I had a big problem on the left side. When I torqued the bolts, the bracket moved enough to create some friction in the pulley. I tried spreading the bracket slightly, but that did not help enough. After taking the bracket off, taking it apart, and replacing it a few times, I realized that the pulley bushing was too short. I replaced it with a slightly longer bushing to prevent the bracket from applying pressure against the nylon washers. I replaced the bracket again, and all was well. I then had to install new cotter pins in the castellated nuts.
1 Nov 2014 (4 hours, total time to date: 1494.0 hours)
Jasson came over this morning. We clecoed the right tail cone skin in place and started riveting the tail cone crown line from the center working forward, then aft. To prevent the skin from "walking" in either direction, I cut & dimpled some washers, and used a small machine screw to firmly clamp the hole ahead of the hole being riveted. This procedure worked very well to keep the skin nice and flat along the seam, and the skins nested nicely. It took some extra time to do this, but I'm happy with the result. As noted above, dimpled skins do not nest perfectly after dimpling with the same die, and some work is required to set the skins. These 0.025 skins are relatively easy to set as they are riveted, but I will squeeze the thicker stacks with 0.032 skins before riveting them.
2 Nov 2014 (1 hour, total time to date: 1495.0 hours)
I removed the forward fin attach doubler & back plate for acid etch/alodine. Once dry, I applied a light coat of primer to the mating surfaces. I also de-greased/etched/alodined/primed the area of the skin under the doubler. Before re-installing the doubler/backing plate, I used a dimpled 0.032 washer into the backing plate attachment holes for a better fit when Jasson and I rivet it in place. Finally, I installed an AN3 bolt in the fin attach hole to maintain hole alignment & hold things firmly in place for riveting.
4 Nov 2014 (3 hours, total time to date: 1498.0 hours)
Jasson came over to help me close up the tail cone. We didn't quite finish - we left a few clecos around the right stabilizer bolt hole because I still need to install a nut plate in that hole. I want to be able to clear any chips from the nut plate holes under the BH flange.
6 Nov 2014 (1 hour, total time to date: 1499.0 hours)
Started work to install a nut plate for the right side stabilizer attachment hole at BH160. I cut an AN3 bolt short to hold the nut plate to the outside of the skin. I slid the bolt through the attachment hole in the doubler (fits inside the tail cone) & lined up the doubler/nut plate. I used duct tape to help hold the parts in place & snugged the bolt. When I was happy with the alignment, I match drilled the nut plate holes from the outside using a #41 bit. Because of the curvature, I wanted to leave a little room to drill the holes out to #40. I then removed the bolt & re-installed the nut plate on the inside of the tail cone. Finally, I drilled out the nut plate holes to #40.
7 Nov 2014 (1 hour, total time to date: 1500.0 hours)
I cut the threads short on a long AN3 bolt so that I could verify that the nut plate was seated properly at the right stabilizer attachment hole with the clecos installed through the nut plate attach holes. I measured the locations for the doubler attachment holes (22/32 in front of the bolt hole). I used a drilling guide (scrap piece of 0.032 sheet) and match drilled (#40) both holes through the doubler from the outside. I then stepped the holes up to #31 and finally to 1/8 in for later dimpling.
It looks pretty good. As Jasson says: "Prior Proper Planning Prevents Piss Poor Performance."
It looks pretty good. As Jasson says: "Prior Proper Planning Prevents Piss Poor Performance."
8 Nov 2014 (2 hours, total time to date: 1502.0 hours)
Before installing the Cherry Max rivets along the right side, I fabricated a test piece to make sure the rivets would set in two sheets of 0.025 thick material. The test piece worked fine, but none of the rivets set properly on the airplane :-( This is just another reason to hate Cherry Max rivets. I used the CR3242-4-1 rivets because the total thickness was 0.05 and the holes were slightly oversized (since these holes were drilled to #30 before dimpling). I had a few scratches to buff out and I'll figure out how to remove these buggers later. I also removed the right stabilizer attach doubler and de-burred the holes.
I managed to duplicate the Cherry Max problem on my test piece.
I managed to duplicate the Cherry Max problem on my test piece.
9 Nov 2014 (2 hours, total time to date: 1504.0 hours)
I practiced drilling out the badly set rivet on the test piece, installed another bad one, and drilled it out. I really enlarged the hole in the test piece, so I'm going to try it again using a 1/8 drill bit to see if that will work better. I'll also wait to see if Jasson wants to give it a go the next time he comes over.
I cut 2 pieces of 2x4 to make a support for the lower tail cone skin to attach to the fuselage jig. I secured some fabric on the support to protect the skin and screwed the support in place. This will hold the tail cone when I remove the clecos from the rear spar carry through, remove the rest of the clecos around the flange of BH99.35, and slide it out to de-burr and dimple the rivet holes. I drilled out the attachment holes for the seat support shear clips to 1/8 in (I'll finish these after I put the BH back). Finally, I drilled out the holes for the rudder pulley support brackets at BH99.35 to #19. I did this in 3 steps (#30, #21, #19). I still need to take them out to #12, but will also do that when I replace the BH after dimpling.
I cut 2 pieces of 2x4 to make a support for the lower tail cone skin to attach to the fuselage jig. I secured some fabric on the support to protect the skin and screwed the support in place. This will hold the tail cone when I remove the clecos from the rear spar carry through, remove the rest of the clecos around the flange of BH99.35, and slide it out to de-burr and dimple the rivet holes. I drilled out the attachment holes for the seat support shear clips to 1/8 in (I'll finish these after I put the BH back). Finally, I drilled out the holes for the rudder pulley support brackets at BH99.35 to #19. I did this in 3 steps (#30, #21, #19). I still need to take them out to #12, but will also do that when I replace the BH after dimpling.
10 Nov 2014 (1 hour, total time to date: 1505.0 hours)
I removed the center bottom skin, drilled out the holding rivets on the forward ends of the center fuselage splice doublers and removed them. Then, I removed the clecos around the flange of BH99.35 and slide the BH out of the tail cone for de-burring, dimpling, and finishing. It came out easily, and I hope I will say the same when I replace it.
11 Nov 2014 (7 hours, total time to date: 1512.0 hours)
A long day. I spent about 2 hours rounding the corners and smoothing the notch roots of the tabs of BH99.35 using my Dremel with an abrasive tool, then with a 1/4 in. sanding drum. Then, I realized that I had forgotten to drill out the seat belt attachment holes on each side of the rear spar through BH99.35. I replaced the BH & drilled the #12 holes on each side. The plastic that I had left on the edges of the tail cone skin was very difficult to remove on the bottom skin. I worked on it for about an hour and was able to remove all of it around the fastener holes. There is still more to remove, but I'll work on that later. I want to run the conduit for the elevator trim inside the arm rests, and this means that the pass through at BH99.35 will be immediately above the 1/8 thick doublers that carry vertical shear from the rear spar into the tail cone skin. I fabricated 0.032 doublers for the back side of the BH to tie into the upper rivets of the large, thick doublers and extend about 3 inches up the web. I laid out the rivet pattern for the additional doublers, and cut 1/2 in. holes for pass throughs on each side. I will install shorty bushings in these holes for the conduit and perhaps some wiring if I need it later. I also laid out -3 rivet holes around the hole. I used -3's instead of -4's because of rivet spacing requirements and the limited space available. Then, I dimpled the attachment holes around the flange of BH99.35 and the 1/8 in. holes in the stabilizer doubler. Finally, I de-greased, etched, and alodined the parts (BH99.35, the 4 doublers, and the small stabilizer attachment doubler), & applied a light coat of primer inside the tail cone in the area of the right stabilzer attach doubler.
12 Nov 2014 (4 hours, total time to date: 1516.0 hours)
I removed the rear spar carry through spar/doubler strip from the fuselage jig, de-burred the BH99.35 fastener holes around the tail cone skin, & finished the skin in this area with scotch brite. I de-greased the inside of the skin & applied a light coat of primer around the bottom half about the inside. I then de-burred/finished/etched/alodined the rear spar & doubler strip. Once the parts were dry, I primed the parts. I used my pneumatic squeezer to dimple the BH99.35 attachment holes in the tail cone skin (with the exception of the holes through the splice doubler since I will be using AN470's there). Jasson came over and looked at the situation with the Cherry Max rivets between BH177.5 & 182. Instead of drilling the cores out, he used a punch (worked well). The expanded bulb was more difficult to remove than expected. We ended up using a 9/64 drill bit to drill through the rivets after the core was removed. These holes were already a little larger than 9/64 and we were using the oversized Cherry's. The other "interesting" thing was that we had to install/remove several rivets before we got them to set properly. For these 4 holes, we probably used 16 rivets before it was over. My theory is that the dimples were not fully seated together, and it took several tries before the process of pulling the rivets actually seated them. This was a good lesson for me. The standard riveting process can usually finish the job of closing the gap between dimples made with the same die - especially in thin skins. However, it is a good idea to re-squeeze skins to help close the gap. In areas where this is not possible, I will squeeze a dimpled "washer" (with a thickness equal to the outside skin that will be riveted) into the inside skin. With that finally over, we riveted the right side stabilizer attachment doubler/nut plate & finished riveting the right skin along BH160.
Another point I like to make regarding the Cherry Max rivet situation is that I also believe that the reason I had better luck with my test specimen was because I was able to support the back side of the specimen with two fingers on each side of the rivet. When doing a blind installation on the airplane, there is no way to support the back side. It seems to me that applying excess pressure against the skin with the puller may also be detrimental because it can cause the dimples to flex apart, and make the nesting situation worse.
Another point I like to make regarding the Cherry Max rivet situation is that I also believe that the reason I had better luck with my test specimen was because I was able to support the back side of the specimen with two fingers on each side of the rivet. When doing a blind installation on the airplane, there is no way to support the back side. It seems to me that applying excess pressure against the skin with the puller may also be detrimental because it can cause the dimples to flex apart, and make the nesting situation worse.
14 Nov 2014 (2 hours, total time to date: 1518.0 hours)
I clecoed the doublers on BH99.35 and started work riveting them in place. There are 2 rivets that I need to replace (bad shop heads). Also, after giving it more thought, I think I should add another -4 rivet between the -3 (holding the web and doubler together around the pass through hole) and -4 rivet along the flange. The -3 can't carry the potential running load over the distance that exists now.
15 Nov 2014 (3 hours, total time to date: 1521.0 hours)
I decided to remove the -3 rivets on each side of the pass through hole in the web of BH99.35 (see picture above) & replace them with -4s. There was adequate edge distance, and I really should have done it from the beginning. I also decided to add a -4 rivet along the BH flange side of the web between the new -4 and the existing rivet (1 inch above). I drilled out the new hole from each side to keep chips from accumulating between the sheets as much as possible. Since I couldn't prevent some chips from getting between the layers, I drilled out one more rivet (above the new hole), and used a 0.007 feeler gauge to carefully fish chips out through the pass through hole. The additional rivet simply provides a little extra capability and helps the 2 layers to act more like one to run most of the load directly into the flange (via the stiffer path). Here's how I see this:
There are 8 -4 rivets carrying load from the rear spar into the BH flange (via the 1/8 in. thick doubler). Assuming 350 #s per rivet, this gives a maximum capability of 2800 #s. Without the thick doubler, the web could not handle this much load (2800/(0.032 * 1.75) = 50,000 psi in compression (ignoring the flanges on each side of the web except for their stabilizing effect). The real load at 9 g's is clearly not 2800 # per side, but why not do everything within reason to maintain the full capability of the structure? There are 4 rivets in the BH flange along the length of the thick doubler that can transfer 1400 #s into the skin. OK, so that leaves another 1400 # to transition into the tail cone skin through the BH web and 0.032 doubler. The two -4 rivets through the top of the thick doubler and the bottom of the 0.032 doubler can transfer 700 # into the 0.032 doubler. This leaves 700 # to pass through the BH web at the pass through hole. The direct path to the skin would go around the outside of the hole, but not all of this load can go along this path because (700/(0.032 * (1.75/2 - 0.25))) = 35,000 psi compression. A lot of the load (probably around 1/3+) can go around the other side and run up the diagonal line of rivets into the skin. I'm not concerned about the hole because the real operational loads are a small fraction of the numbers shown above.
Finally, I spent a little time polishing the area around the doublers, added the shorty bushing & reinstalled the BH back in the tail cone.
There are 8 -4 rivets carrying load from the rear spar into the BH flange (via the 1/8 in. thick doubler). Assuming 350 #s per rivet, this gives a maximum capability of 2800 #s. Without the thick doubler, the web could not handle this much load (2800/(0.032 * 1.75) = 50,000 psi in compression (ignoring the flanges on each side of the web except for their stabilizing effect). The real load at 9 g's is clearly not 2800 # per side, but why not do everything within reason to maintain the full capability of the structure? There are 4 rivets in the BH flange along the length of the thick doubler that can transfer 1400 #s into the skin. OK, so that leaves another 1400 # to transition into the tail cone skin through the BH web and 0.032 doubler. The two -4 rivets through the top of the thick doubler and the bottom of the 0.032 doubler can transfer 700 # into the 0.032 doubler. This leaves 700 # to pass through the BH web at the pass through hole. The direct path to the skin would go around the outside of the hole, but not all of this load can go along this path because (700/(0.032 * (1.75/2 - 0.25))) = 35,000 psi compression. A lot of the load (probably around 1/3+) can go around the other side and run up the diagonal line of rivets into the skin. I'm not concerned about the hole because the real operational loads are a small fraction of the numbers shown above.
Finally, I spent a little time polishing the area around the doublers, added the shorty bushing & reinstalled the BH back in the tail cone.
16 Nov 2014 (2 hours, total time to date: 1523.0 hours)
I installed the avionics decks & started work riveting the upper portion of BH99.35 (above the longerons) to the tail cone skin. I started by squeezing a dimple die in each attachment hole to fully set the dimples together. I had installed clecos in every other hole, then alternated the clecos & squeezed the remaining holes. I started riveting each side from the top & used cleco clamps to help hold the skin to the BH flange where the curvature was the most severe. I finished the first pass around the top and removed the clecos. I will rivet the remaining holes tomorrow.
17 Nov 2014 (1 hour, total time to date: 1524.0 hours)
I finished riveting the upper portion of BH99.35 to the tail cone skin and did some light polishing of the tail cone.
18 Nov 2014 (1 hour, total time to date: 1525.0 hours)
I installed a few clecos & drilled out the holding rivets along the upper longerons and the holding rivets between the lower longerons (stringers) and the doublers at BH73.75. I also drilled a #41 hole on each side & installed a cleco to make sure the lower longerons would not move after the rivet was removed. I started work drilling these holes out to #31 to clean them up after removing the rivets, and I did not want anything to move during the process.
19 Nov 2014 (1 hour, total time to date: 1526.0 hours)
I finished cleaning up the holes that had been filled with NAS1097-3 "holding" rivets & started work to remove the upper longerons. I had to remove the bolts holding the upper engine mount fittings in order to remove the longerons. I also removed the instrument panel and associated parts.
21 Nov 2014 (1 hour, total time to date: 1527.0 hours)
I de-burred the holes along the inside of each longeron, and started work to countersink the holes that attach to the tail cone. I used a piece of 0.025 thick scrap material to make a template to check the depth of C/S. I drilled a 1/8 in. hole in the template and dimpled it. I then used a scrap piece of 0.125 thick aluminum, drilled a few #30 holes, and used it to "dial in" my C/S cage to get the proper depth to seat the dimpled holes in the tail cone skin. I also double checked the depth by inserting a rivet in the C/S hole and used my digital caliper to measure how far the rivet head sat below the surface. Ideally, the rivet heat should set below the surface by: 0.025/sin(50) - 0.025 = .0076 - this seemed about right. I measured approx. 0.006 for the rivet head, and the template seemed to nest well. For the hole at BH99.35, the C/S will need to be deeper to account for the nesting of the center skin. Anyway, I started to C/S the left longeron before I ran out of time for the day.
22 Nov 2014 (2 hours, total time to date: 1529.0 hours)
Well, yesterday I wrote that a C/S depth that resulted in a rivet head 0.006 below the surface seemed to nest well. After looking at it more carefully, and shining a bright light between the layers, that was not quite enough. After more trial and error with the scrap material, it looked like 0.008 to 0.0085 was the right number. This was also after carefully de-burring the upper edge of the C/S with a large drill bit. I went over the holes that were C/S yesterday, and then finished the rest of the holes in the longerons that attach to the tail cone skin. Then, I squeezed a dimpled piece of 0.032 material with the 0.025 template to simulate the center skin/tail cone skin connection at BH99.35. The BH flange is cut out in this location, so there are only these two layers at these holes (on each side). After more trial and error, it looked like 0.013 was the amount of rivet head recess that would allow the dimpled skins to nest nicely. I C/S these two holes & did some minor de-burring and finishing of the longeron/tail cone.
23 Nov 2014 (1 hour, total time to date: 1530.0 hours)
I built a small stand to hold BH73.75 inverted to drill out the lower skin fastener holes & make it easier to install the nut plates.
24 Nov 2014 (1 hour, total time to date: 1531.0 hours)
I removed BH73.73 from the fuselage jig & clamped it (inverted) on my new stand. I then used a Black & Decker workbench and another stand to support the tunnel and center bottom skin. I clecoed the skins through the lower doubler & flange of BH73.75. The lower doubler holds the skins in alignment & provides a better connection between the tunnel and bottom, center skin. I drilled out the 4 center holes in the bottom flange of BH73.75 out to 1/8 in. I plan to install nut plates in these holes since there is no way to buck standard rivets, & I don't want to use Cherry's anywhere unless there is no other choice.
25 Nov 2014 (4 hours, total time to date: 1535.0 hours)
I dis-assembled the lower center skin/tunnel & drilled out the holding rivets for the lower doubler. I re-assembled the structure to finish drilling out the holes along the lower splice line to 1/8 in. Jasson came over to help me dimple the holes in the tail cone skin for the upper longerons & install the last rivet at the tail cone crown line (next to BH99.35). Jasson also helped me finish drilling out the fastener holes along the bottom of BH73.75. He convinced me to forget about installing nut plates & simply use nuts and install them wet (with fuel tank sealant). These screws aren't coming out anyway, & we can use hemostats to get the nuts in place. I'll probably use large head structural machine screws since there are 4 layers of material at the flange (the doubler adds a layer). We installed the forward side skins & used a hole finder to drill out the attachment holes on the lower flange line. I also had to cut off the last inch or so of the tunnel flange to allow the skins to sit flush. I allowed for overlap of the side skins because I could see no other way to secure the aft portion of the tunnel flange. There was no way to rivet the tunnel side to the floor near the aft end (because of the taper).
26 Nov 2014 (2 hours, total time to date: 1537.0 hours)
I pre-drilled 2 attachment holes in the flange of BH73.75 between the wing attach lugs on each side. I had installed a holding rivet at the lower holes on each side to keep the doublers formed around the curvature of the flange in this area. To locate the holes between the wing attach bolts in the center/forward skin splice, I removed the skins from the jig & drilled out the holding rivets on each side of the doubler between the wing attach bolts. The doublers are still secured along the flange by 4 more holding rivets above the wing attach bolts. I then replaced the lower center skin and used a duplicating strap to locate the holes on each side & drill the #40 pilot holes in the center skin. I used the existing holes in the side doublers to ensure that the center skin was in position before drilling the pilot holes. So, I had to remove the clecos between the skin/doubler, insert the duplicator nib in he desired hole, duct tape the duplicator to the doubler (to keep in in the hole), replaced the clecos to align the skin, and drill the pilot hole through the duplicator. I repeated this process for each hole (4X), and checked the fit each time. I had to run the #40 bit through the stack for 2 of the holes, but the mis-match was minor. This is the other reason to do this with a #40 pilot hole :-) Once this was done, I took some time to remove the spark plugs from my engine, re-oil the cylinders, and installed dessicant plugs in the upper plug holes.
27 Nov 2014 (1 hours, total time to date: 1538.0 hours)
I replaced the forward side skins & used my hole finder to drill the 2 pilot holes on each side between the wing attach bolts. I used the same process noted above for the lower center skin. I had to remove and replace each skin 3 times to drill out the holes and finally to check them.
28 Nov 2014 (1 hour, total time to date: 1539.0 hours)
I removed the forward side skins & used the hole duplicator to drill out 3 more pilot holes in the splice doubler on each side of the lower center skin. These holes are blocked on the inside by the vertical shear angles. Once these holes were drilled, I drilled out the remaining 3 holding rivets on each BH73.75 splice doubler.
29 Nov 2014 (1 hour, total time to date: 1540.0 hours)
I clecoed each BH73.75 splice doubler to the corresponding forward side skin & match drilled the pilot holes that are blocked from the inside by the forward vertical shear angles betwen the wing attach bolts. I also did some light de-burring of the forward side skins.
30 Nov 2014 (2 hours, total time to date: 1542.0 hours)
I deburred the 1/8 in. attachment holes in the lower center skin at BH99.35 & dimpled them with my pneumatic squeezer. I replaced BH73.75 in the fuselage jig with the splice doublers, attached the center skin splice doublers, & clecoed the lower center skin in place. It took some time to get the lower center skin back in place. Once it was secure, I needed to run a #41 drill through a few of the new holes to install clecos. Again, this is why it is a very good idea to drill smaller pilot holes during the fitting process. Now that the lower center skin is back in place, I can start working on the arm rests tomorros.
1 Dec 2014 (1 hour, total time to date: 1543.0 hours)
I replaced the seat BH, supports, & the flap actuator handle so that I could lay out the location for the arm rests. I want to be careful to leave enough seat room and be able to use the structure to secure the flap control quadrant. The space inside the jig I just made to hold BH73.75 inverted is 15 in., and I fit inside (not much to spare), and it seemed to work out nicely to have 15.75 in. at BH99.35 & 16.5 in. at the seat BH. I ran some string to indicate the location of the inside of the arm rest on the right side. That leaves 2.5 in. width for each arm rest.
2 Dec 2014 (1 hour, total time to date: 1544.0 hours)
I fabricated a cardboard template for the sides of the armrests & test fit it on the right side of the cockpit. Then, I cut a piece of 0.032 aluminum & did some finishing work on the straight edges.
3 Dec 2014 (1 hour, total time to date: 1545.0 hours)
I completed the initial trimming/finishing of right side arm rest & bent the attachment flange to the bottom, center skin. I test fit the piece in the cockpit & made some adjustments to the flange bend. Finally, I cut the left arm rest piece out of another scrap piece of 0.032 sheet.
5 Dec 2014 (1 hour, total time to date: 1546.0 hours)
I did some minor trimming to fit the left arm rest in the cockpit, finished the inside corners/edges, and bent the attachment flange to fit.
7 Dec 2014 (1 hour, total time to date: 1547.0 hours)
Laid out the fastener hole patter along the lower attachment flanges of both arm rests (1.5 in. spacing). Aligned them in the cockpit & match drilled the aft attachment holes through the bottom skin.
12 Dec 2014 (1 hour, total time to date; 1548.0 hours)
OK, back to work...... I measured the approximate dimensions for the stand-off support for the forward flap actuator control quadrant. To hold it in place, I taped the aft end to the right arm rest support. Then, I cut/tapered a piece of 2x4 to fit between the quadrant and the lower skin so that I could use it as a form to make a cardboard template for the attachment bracket. I started work on the template and made the first test fit.
13 Dec 2014 (3 hours, total time to date: 1551.0 hours)
I decided to secure the aft end of the flap actuator quadrant to the right armrest support before going any further with the forward attach bracket. The allignment is a little tricky, so it will help to have the quandrant in place first. I plan to attach a doubler in the armrest support to provide more bearing area for the aft attachment bolt, so I cut a piece of 0.032 and taped it to the inside of the armrest as a spacer. I carefully positioned the quadrant in place & clamped the aft end to the armrest. The concern here was to allow the right amount of travel for the flap handle. I had to have at least 15 inches between the handle and seat back BH (the distance between my grip and my elbow is a little less than 15 inches), and have proper clearance between the handle and the spar caps of the wing carry through (BH73.75). I removed the armrest support (with the quadrant still clamped in place), marked the location for the hole, and drilled a #12 hole through the support and the spacer. I bent a flange in piece of 1.125 in. wide 0.032 sheet to attach to the inside of the quadrant & clamped it to the center skin splice doubler flange. This secures the quadrant from side to side. I used a short AN3 bolt to allign the holes in the support/aft quadrant & made necessary adjustments to the cross piece. I used a 3/16 duplicating punch to locate the hole in the flange of the cross piece, removed it, and drilled the attachment hole. I then replaced the cross piecs and bolted the assembly together and re-clampe the side piece to the doubler flange. Finally, I rechecked the alignment & match drilled the remaining pilot attachment holes along both armrest flanges.
14 Dec 2014 (1 hour, total time to date: 1552.0 hours)
Now that the quadrant is in place, I can see that the forward bracket template needs to be modified. I made a new template and replaced it in the cockpit. The taper and curvature of the lower skin makes this piece a bit more difficult to fit. More adjustments are needed, but I'm getting closer. :-) Cardboard templates are very helpful, but I'll see how it translates to the real thing soon enough.
15 Dec 2014 (1 hour, total time to date: 1553.0 hours)
I ended up making 3 more cardboard templates before I was happy with the fit along the forward edge of the flap quadrant. Now, I need to work out the stiffening flanges and get ready to make the part.
16 Dec 2014 (1 hour, total time to date: 1554.0 hours)
I started work fabricating the forward quadrant bracket from 0.032 thick 2024-T3 aluminum. I cut out the blank (adding room for stiffening flanges), measured/marked the bend lines, & made the the initial outer and inner bends. I was able to bend the outer flanges with my brake, but had to use hard wood forms for the inner bends.
17 Dec 2014 (1 hour, total time to date: 1555.0 hours)
Continued work fitting the forward flap control quadrant bracket in the cockpit. I adjusted the flange bends as well as the inner bends & trimmed/finished the edges and stress relief notch for the side stiffening flange.
19 Dec 2014 (2 hours, total time to date: 1557.0 hours)
I did a little more trimming around the edges of the rear and side stiffening flanges of the forward flap quadrant bracket using my Dremel tool. I bent the rear flanges first using forming blocks and plastic mallat. I then fabricated a forming block to fit inside the bracket to bend the side stiffening flange. Once the fit looked good, I clamped the new block inside with another block on the outside to support the surface and bent this flange. I then did a little more finishing around the corners of the bends. I replaced the bracket to check the fit & measured the location of the upper, rear flange attachment hole. I punched a pilot hole in the flange, drilled it out to #31, marked the riven line on the flange, clecoed the flange to the lower center skin, aligned the flang alone the fastener holes, duct taped it in place, & match drilled the remaining upper flange attachment holes.
20 Nov 2014 (2.5 hours, total time to date: 1559.5 hours)
I removed the bracket, measured, & cut stiffening flanges for the forward end of the bracket. It took a little time to trim/finish the edges & add stress relief cut outs. I used a 3/16 drill bit to start the stress relief cut-outs along the front side. Once I completed the finishing work around the flanges, I bent the top & bottom flanges with small forming blocks. Then, I fabricated a small forming block to fit inside the bracket, clamped another block on the outside, & bent the front flange over the previously bent flanges. I replaced the bracket & re-checked the fit. I needed to add more of a bend to the lower attachment flange. I removed the bracket & made the adjustment to this flange.
21 Dec 2014 (2.5 hours, total time to date: 1562.0 hours)
I fabricated two doublers to for the front and inside of the flap quadrant bracket. This is taking some serious time, but I want to be sure that the bracket is stiff enough to prevent movement (and possible cracking at the corners down the road). Before I can install these doublers, I needed to determine the final shape of the bracket when finally installed on the lower, center skin. I punched the attachment holes along the lower flange, replaced the bracket, made adjustments to the position of the flange to line up the side with the edge of the flap quadrant, & match drilled the attachment holes through the skin. Now, another problem was how to install the doublers and maintain the proper shape of the bracket. It would be very difficult to drill the attachment holes with the bracket on the airplane. So, I used a scrap piece of 0.032 sheet (the same piece I used as the base for my elevator bellcrank housing), cut it to size (left it long to allow easier forming), and hand formed it to match the curvature of the lower, center skin at the bracket. I match-drilled the #31 holes through the upper flange into the formed sheet, clecoed it inside the skin, & match drilled the lower #41 holes through the skin. Once this was finished I cut the formed sheet about an inch below the lower flange. This allows me to finish the bracket as if it were clecoed in the airplane.
22 Dec 2014 (1 hour, total time to date: 1563.0 hours)
I fabricated an angle stiffener to attach inside the bracket along the cut-out that provides clearance for the flap actuator handle. I also fabricated a "cap" to fit across the rear stiffening flanges. Finally, I trimmed/finished these parts.
23 Dec 2014 (1.5 hours, total time to date: 1564.5 hours)
I laid out the fastener pattern along the angle stiffener that I fabricated yesterday & transferred the pattern to the top of the flap quadrant bracket. I then laid out the fastener pattern to secure the internal doubler on the top of the bracket. I drilled the #41 pilot holes in the top of the bracket. It was easier to do this on my drill press. Then, I clamped the internal doubler inside the bracket so that both sides were in contact with the inside of the bracket & match drilled the pilot holes through the upper side of the doubler. Finally, I clecoed the doubler inside the bracket (leaving the fastenr row for the angle stiffener open), replaced the angle stiffener, & marked the locations of the aft fastener on the stiffener with a fine point sharpy. There was no good way to secure the stiffener inside the bracket, so I drilled the aft pilot hole and clecoed it inside the bracket. Once this was done, I could rotate the stiffener to allign it, duct taped it in place, & match drilled the remaining attachment pilot holes.
25 Dec 2014 (0.5 hour, total time to date: 1565.0 hours)
Merry Christmas!
I spent a little time working on the forward flap quadrant bracket. I laid out the location for 3 rivets below the bracket attach bolt to secure the inner doubler. I drilled the #41 pilot holes in the bracket, replaced the inner doubler, & match drilled the pilot holes through the doubler.
I spent a little time working on the forward flap quadrant bracket. I laid out the location for 3 rivets below the bracket attach bolt to secure the inner doubler. I drilled the #41 pilot holes in the bracket, replaced the inner doubler, & match drilled the pilot holes through the doubler.
26 Dec 2014 (3 hours, total time to date: 1568.0 hours)
I decided to make a new read cap for the bracket and include a stiffening flange along the outside edge to provide more stability. Then, I laid out the fastener pattern for the caps on each end, & drilled #41 pilot holes in both caps. I located one fastener along the vertical flange for the front cap. Since this flange is on the outside of the cap, I drilled this pilot hole in the bracket flange. I replaced the caps (duct taped them in place) & match drilled the pilot attachment holes. With everything clecoed in place, I replaced the bracket on the lower center skin & located the attachment hole for the AN3 bolt that secures the forward end of the flap actuator quadrant. I used a duplicating punch to mark the hole center, removed the bracket, & drilled a pilot hole at this location. I enlarged the hole to #21, replaced the bracket in the airplane, used a -5 cleco to hold the bracket in place, & double checked the alignment of the quadrant (l0oked very good). Then, I removed the bracket assembly & drilled this hole out to #12 for the AN3 bolt. I then used one of my AN3-3 bolts that I had cut the threads short to hold a nut plat in position on the bracket & match drilled the nut plate holes through the assembly. Finally, I spent the remaining time de-burring/finishing the parts.
27 Dec 2014 (2 hours, total time to date: 1570.0 hours)
I dimpled some of the holes between the bracket and inner doubler where it made sense to me. I didn't dimple the holes along the stiffening angle because there are 3-layers, and there wasn't anything to gain by doing it. Dimpling the holes on the quadrant mounting side, gives a nice, flat surface. Then, I degreased, etched, alodined, & primed the mating surface areas in preparation for assembly.
28 Dec 2014 (4 hours, total time to date: 1574.0 hours)
Finally finished the forward flap actuator quadrant bracket. I clecoed the parts together & started by riveting the inner doubler. Once finished, I used a short AN3 bolt to hold the nut plate in place, lightly C/S the outside to accommodate the NAS1097-3 rivets, & squeezed them. Then, I clecoed the assembly to the curved piece of aluminum that mimics the lower skin & clecoed the end caps in place. I really didn't have to do the last step, but I wanted to be sure that everything was still in the right place. I removed the assembly & riveted the end caps. The rear cap was a bit problematic because of the tight angle at the top. I ended up having to drill out the -3 button head rivets, open up the holes to #30, & install NAS1097-4s there. Once the bracket was finished, I replaced it in the airplane & drilled out the attachment holes to 1/8 inch along the top and #31 along the bottom. I'll probably use C/S rivets along the bottom, but will have to use standard rivets along the top because there are 4 layers of material. These holes will be finished later when I'm gettting ready to rivets the skins in place.
29 Dec 2014 (1 hour, total time to date: 1575.0 hours)
I resumed working on the seat. I cut two 1.5+ x 14 x 0.032 inch strips to use as seat supports along the arm rests. I finished the edges and made the initial bend on each piece.
30 Dec 2014 (1 hour, total time to date: 1576.0 hours)
I cut and finished the ends of each support angle to fit inside the armrests. Then, I laid out the rivet spacing & punched the pilot holes in the angles.
1 Jan 2015 2015 (2 hours, total time to date: 1578.0 hours)
I positioned each seat support angle bracket on the corresponding armrest & marked the position with a fine tip sharpie. I removed each armrest, match drilled the attachment pilot holes, clecoed the angles in place, & replaced the armrests. Then, I used more cardboard to fabricate a seat bottom template.
2 Jan 2015 (1 hour, total time to date: 1579.0 hours)
I transferred the seat bottom pattern to a piece of 0.032 thick 2024-T3 aluminum sheet, cut, trimmed, & lightly finished the edges. I test fit it in the cockpit & tried it on for size with Mikey :-)
3 Jan 2015 (3 hours, total time to date: 1582.0 hours)
I made a few adjustments to the seat bottom to improve the fit. I positioned the side supports so that the aft end of the seat was slightly elevated on each side (provides some curvature). Therefore, I needed to increase the bend in the support flanges toward the aft end. I also made sure that the arm rest sides were flush with the inside flange of BH99.35 and tapered inward slightly to match the spacing used on the right side to attach the aft end of the flap control quadrant. This amounts to a 2.5 inch width at the front of the seat. The space between the arm rest and the bottom center skin will be used for elevator cable/wire to the tail cone.
I then started work laying out the fastener pattern to attach the seat bottom to the supports. I started along the seat BH flange, then worked down the two center support flanges. I used a spacing of 2.67 inches along the seat BH & just under 3 inches along the center supports. I will use #8 C/S machine screws to attach the seat bottom, so I needed to be sure to have clearance for the nut plates. The fastener pattern along the seat BH was easy to measure from the front edge. I laid out the fastener lines along the center supports between BH99.35 and the seat BH, transferred the end points to the seat bottom, & drew the resulting fastener line on the seat bottom. I drilled the #41 pilot holes in the seat first, then replaced it, & match drilled through the supports. I did this in stages to check the alignment and make any necessary adjustments to the lines.
I then started work laying out the fastener pattern to attach the seat bottom to the supports. I started along the seat BH flange, then worked down the two center support flanges. I used a spacing of 2.67 inches along the seat BH & just under 3 inches along the center supports. I will use #8 C/S machine screws to attach the seat bottom, so I needed to be sure to have clearance for the nut plates. The fastener pattern along the seat BH was easy to measure from the front edge. I laid out the fastener lines along the center supports between BH99.35 and the seat BH, transferred the end points to the seat bottom, & drew the resulting fastener line on the seat bottom. I drilled the #41 pilot holes in the seat first, then replaced it, & match drilled through the supports. I did this in stages to check the alignment and make any necessary adjustments to the lines.
4 Jan 2015 (2 hours, total time to date: 1584.0 hours)
It appears that the seat needs more reinforcement to reduce the amount of deflection (especially, at the aft end where there is less clearance with the elevator push rod). I'd like the supports to buckle in case of a crash, but want to find the "sweat" spot as far as possible. I finished drilling out the pilot holes along the supports at the arm rests and started work on the reinforcements. I added a piece of 0.062 angle between the center supports (at the mid-point). I trimmed the outstanding leg down to approx. 3/8 inch to provide plenty of clearance for the push rod. I'm planning to run some 0.032 bent angles from the 0.062 running aft to BH99.35 (on each side of the push rod), and may add some stiffeners to the inside of the center supports to bridge more load to BH99.35 and the seat BH.
5 Jan 2015 (1 hour, total time to date: 1585.0 hours)
I fabricated a 0.032 reinforcement angle to fit laterally between the inner seat supports between the seat BH and the heavier angle I installed yesterday. This simply reduces the deflection of the seat bottom in this area. I laid out the fastener pattern & drilled the pilot attachment holes for this reinforcement.
6 Jan 2015 (1 hour, total time to date: 1586.0 hours)
In order for the aft seat reinforcement angles to attach to the support angle at BH99.35, I need to install a 0.032 inch thick doubler in this area of the seat bottom. This will act as a spacer for the angles and stiffen up the seat bottom at the same time. The aft end of the angles need to slide under the aft support angle with a nut plate installed to receive the attachment machine screw. I cut out the lightly finished this doubler and fabricated a cardboard template of the aft seat reinforcement angles.
7 Jan 2015 (1 hour, total time to date: 1587.0 hours)
I cut out the blanks for the two, aft seat reinforcement angles, finished the edges, & bent the flanges.
9 Jan 2015 (1 hour, total time to date: 1588.0 hours)
I trimmed/finished the ends of the reinforcement angles to fit, & laid out the fastener pattern. I then drilled the pilot attachment holes in the angles. I laid out the angles on the seat bottom for the photo.
10 Jan 2015 (1 hour, total time to date: 1589.0 hours)
I double-checked the location for the attachment hole at the aft end of the angles (to be sure there was adequate edge distance on the support angle at BH99.35). I then taped the angles in place & match drilled the pilot holes through the local doubler/seat bottom. I removed the angles/doubler, replaced the seat bottom, and match drilled the pilot attachment holes through the support angle. Finally, I replaced the doubler/angles & test fit the seat bottom in the cockpit.
11 Jan 2015 (3 hours, total time to date: 1592.0 hours)
I marked/trimmed/finished the doubler as needed for the aft angles. As I mentioned earlier, this doubler is mainly a spacer to allow the ends of the angles to slip under the seat support angle at BH99.35. However, I decided to use the additional material to provide a little more bending stiffness between the center seat supports. I cut holes in the center of the doubler & trimmed the edges along the inside of each angle. I added a few more attachment holes to secure the doubler to the seat bottom & match drilled these holes. Finally, I fabricated two more reinforcing angles to run along the outside of the seat bottom (between the center supports and the arm rests). The arm rests aren't secured to the BHs (no good way to do it at BH99.35 - at least not that I could think of), so these will help stabilize the seat bottom on each end.
12 Jan 2015 (1 hour, total time to date: 1593.0 hours)
I trimmed/finished the outboard reinforcement angles to fit between BH99.35 & the seat BH. Then, I laid out the fastener locations (1 inch spacing), & punched the pilot holes.
13 Jan 2015 (1 hour, total time to date: 1594.0 hours)
I positioned the new reinforcement angles, used duct tape to secure them, & match drilled the pilot holes through the seat bottom. I also removed the center/aft reinforcements to adjust the bend along the aft end to allow it to slide more easily under the support angle at BH99.35. I replaced the aft angles on the seat bottom/doubler.
14 Jan 2015 (0.5 hour, total time to date: 1594.5 hours)
I replaced the seat bottom assembly in the cockpit & drilled out the aft attachment holes through the central reinforcement angles and the aft support angle at BH99.35 to #12 since I will be using #10 machine screws here & I need to install the nut plates on these angles before I can rivet them to the seat bottom. Then, I started drilling out the attachment holes for the seat bottom reinforcements to 1/8 inch (since they will be dimpled).
16 Jan 2015 (1 hour, total time to date: 1595.5 hours)
I realized that I should have drilled out the other 2 aft support attachment holes to #12 so that I can drill the nut plate attachment holes & prepare the support angle to be riveted to BH99.35. I replaced the seat bottom & drilled out these holes. I removed the seat bottom & aft support angle. Then, I started de-burring the parts.
17 Jan 2015 (3 hours, total time to date: 1598.5 hours)
I took the seat assembly apart & de-burred the holes in each piece. I removed the plastic from the seat bottom. de-burred the holes for the removed pieces, & finished the edges of the parts. I used my c-frame table to dimple all of the parts in preparation for final finishing. Finally, I drilled the nut plate attachment holes for the two outboard attachment holes in the aft support angle.
18 Jan 2015 (2.5 hours, total time to date: 1601.0 hours)
I C/S the attachment holes in the 0.062 thick stiffening angle that fits forward of the aft, central seat bottom stiffening angles. I removed the seat support shear clips that attach to BH99.35, & drilled out the attachment holes to #30. I went over all of the parts again with scotch brite, degreased, acid etched, & alodined them. Once the parts were dry, I applied a light coat of primer to the mating surfaces.
19 Jan 2015 (1 hour, total time to date: 1602.0 hours)
I riveted the nut plates to the aft support angle (2) and the aft seat, central seat stiffeners. I screwed up one rivet on the right stiffener & had to drill it out, but other than that, all went smoothly.
20 Jan 2015 (1 hour, total time to date: 1603.0 hours)
Started riveting the stiffeners on the seat bottom. I used my pneumatic squeezer to set the rivets that could be reached near the edges of the seat.
21 Jan 2015 (1 hour, total time to date: 1604.0 hours)
Continued riveting the stiffeners to the seat using the flush set on my 3X rivet gun. I attached each stiffener in the middle of the seat, but left a few holes open. I also left the heads a little high and plan to finish up by back riveting the remaining holes and setting all of the heads to the correct height.
22 Jan 2015 (1 hour, total time to date: 1605.0 hours)
I finished riveting the stiffeners on the seat using my back riveting set. Since the material is relatively thin, I don't see any issues with back riveting that I saw with the thick (0.5 in.) piece that I experimented with for the elevator bell crank.
23 Jan 2015 (1 hour, total time to date: 1606.0 hours)
I removed the left armrest support & trimmed it to align with the upper edge of the lower skin flange. I finished the edge & replaced it in the cockpit. I also replaced the seat bottom so that the armrests would be in their proper position/alignment. Then, I cut a piece of 0.032 (3.5 x 1.25) to fit across the top of the arm rest at the front end (as I did on the right side where the attachment bolt secures the flap quadrant). I finished the edges & bent the piece to fit to the arm rest support.
24 Jan 2015 (2.5 hours, total time to date: 1608.5 hours)
I trimmed the arm rest supports so that the top edges would fall just below the level of the lower center skin flanges. It took a few iterations to get the fit the way I wanted. I also adjusted the bend in the skin flanges so they were level. I drilled a pilot attachment hole through the left armrest support for the forward attachment tab. I finished the edges of the supports and replaced them in the cockpit. I clamped the left forward support strip to the skin flange/arm rest support & match drilled the pilot hole through the tab.
25 Jan 2015 (3.5 hours, total time to date: 1612.0 hours)
I decided to fabricate new seat belt attachment brackets from 0.125 thick 2 x 2 angle stock. The brackets will serve dual purposes. First, they will allow me to attach the lap belts with a bolt through each arm rest support. The second purpose will be to support the aft ends of the arm rests. Previously, I wrote that I couldn't think of a good way to attach the arm rests to BH99.35 and the seat back BH. Well, I stand corrected :-)
I fabricated both brackets to fit on the lower doubler at BH99.35 & allign with the arm rest supports. I installed the brackets to demonstrate the fit.
I fabricated both brackets to fit on the lower doubler at BH99.35 & allign with the arm rest supports. I installed the brackets to demonstrate the fit.
27 Jan 2015 (1 hour, total time to date: 1613.0 hours)
I came up with a way to attach the front of the arm rests to the seat BH that would provide a reasonably secure attachment and not be difficult to rivet in place. I made a cardboard template to fit, then cut out one blank from 0.032 thick aluminum sheet. I did some light finishing work on the blank and will use it as the template for the other side before bending the tab.
28 Jan 2015 (2 hours, total time to date: 1615.0 hours)
I cut the second attachment bracket for the forward end of the arm rests, & finished the edges of both parts. I bent the attachment tabs for both parts to make them right & left specific. I then removed the flap actuator torque tube to allow better access to the front of the seat BH for attachment of the new brackets. I test fit each bracket, trimmed the tabs & made a slight bend to allow the right bracket to clear the flap actuator handle in the full aft position. I decided to make each side the same for aesthetic reasons.
30 Jan 2015 (1.5 hours, total time to date: 1616.5 hours)
I laid out the fastener hole pattern in the left armrest bracket & checked for clearance with the existing tooling hole in the web of the seat BH. I also checked for clearance for my drill with the lower skin. I drilled the attachment pilot holes in the left bracket and replaced it on the seat BH. I used duct tape to hold it in place so that the upper flange was seated against the arm rest support. I then match drilled the 3 pilot attachment holes through the seat BH web. I repeated the process on the right side and the result is shown here.
31 Jan 2015 (1 hour, total time to date: 1617.5 hours)
I removed the seat bottom & used a hole duplicator to drill the pilot attachment holes through the arm rest supports and the forward bracket tabs. I also removed the right armrest support to trim/finish the forward edge to properly clear the flap actuator handle in the full aft position. I then replaced the support & seat bottom in the cockpit.
1 Feb 2015 (2 hours, total time to date: 1619.5 hours)
I fabricated inside corner brackets for the aft end of the arm rest supports. These brackets will attach to the seat belt brackets on the outside of the arm rest supports and help reduce bending of the seat belt brackets in case they are needed.
2 Feb 2015 (1.5 hours, total time to date: 1621.0 hours(
I marked the aft sides of the seat bottom to be trimmed to provide clearance for the 0.062 thick inner corner brackets. I removed the seat bottom, trimmed, & finished the edges. Then, I test fit each bracket & made some slight adjustments to bottom of the brackets to improve the fit. I clamped each bracket in place along the front side of the web of BH99.35 (holding the other leg firmly against the armrest & seat belt bracket on the other side). I had to remove the avionics decks so that I could match drill the attachment hole through the existing #21 holes through the rear spar carry through. Before drilling these holes (the clamps were in the way), I match drilled the 3 attachment pilot holes through each armrest/seat belt bracket & installed clecos to hold them in place. I then removed the clamps & match drilled the #21 holes through the rear spar carry through. I'll be enlarging these to #12 for AN3 bolts later since a standard -5 rivet doesn't have sufficient tensile strength to match the shear capability of the 3, AD4 rivets that will attach the bracket to the armrest/seat belt bracket.
This photo also shows how I plan to run the elevator trim cable & wiring inside the armrests. I will be fabricating a removable top cover for each armrest.
This photo also shows how I plan to run the elevator trim cable & wiring inside the armrests. I will be fabricating a removable top cover for each armrest.
3 Feb 2015 (1 hour, total time to date: 1622.0 hours)
I will be installing nut plates for #8 machine screws along the upper edge of each arm rest to attach the top cover. I'd like to space the nut plates at approx. 3 inches (simply because I don't want it to take all day to remove the covers). I'm expecting an issue with stability between the nut plates, so I going to install doublers on the supports to go along the top edge and extend vertically at two locations along the span (to add more buckling strength). I removed the left arm rest support and started work fabricating that doubler from 0.032 thick 2024-T3 sheet. I cut the blank to the rough size, clamped it to the support, & match drilled 3 pilot holes along the fastener line that exists for the seat bottom support. I then drew the approximate pattern for the doubler.
4 Feb 2015 (1 hour, total time to date: 1623.0 hours)
I marked the location of the hole centers for all of the fillet radii in the doubler. I then cut 0.5 in. diameter holes at these locations & used a Dremmel cutting wheel to make the inside cuts.I finished the cuts on my band saw, & started finishing the edges.
6 Feb 2015 (1 hour, total time to date: 1624.0 hours)
I trimmed & finished the bottom edge of the left armrest support doubler to remove some excess material. I then removed the right armrest support, cut out the doubler blank, match drilled the 3 pilot attachment holes along the seat support line, & laid out the doubler pattern.
7 Feb 2015 (2 hours, total time to date: 1626.0 hours)
I marked the centers for the 0.5 in. fillet radii cuts in the right armrest doubler, cut these holes, made the inside cuts with my Dremmel, & finished all of the edges. I then laid out the fastener pattern and drilled all of the pilot attachment holes in the left armrest doubler. The difference seen in the right doubler is to reinforce the area around the attachment hole for the flap quadrant.
8 Feb 2015 (2 hours, total time to date: 1628.0 hours)
I laid out the C/Ls for the fastener holes in the right BH doubler & used the left doubler as a drilling template. The two parts are not identical, so I lined up the C/L and drilled each portion of the doubler. I got a little ahead of myself on the forward vertical support (neglected to line up the existing fastener hole), so I had to stop to repair the doubler by installing a NAS1097-3 rivet to fill the hole that was in the wrong location. Fortunately, there was enough clearance to salvage this mistake. I finished drilling out the pilot attachment holes and checked the clearance for the other brackets that attach to the arm rest support. I had to trim the aft part of each doubler to clear the seat belt bracket. I also located the flap control quadrant attachment hole in the right doubler & used a duplicating punch to locate the hole. I drilled this hole to size & drilled additional attachment holes in the area to secure the doubler around this hole. There is limited room here, so I was very careful to allow clearance for the quadrant and for the forward nut plate to attach the armrest cover.
9 Feb 2015 (1 hour, total time to date: 1629.0 hours)
I removed the left seat belt bracket & located the seat belt attachment hole. I drilled a #30 pilot hole in the bracket, replaced it on the armrest, & match drilled the pilot hole. Finally, I re-assembled the armrest/seat support/seat belt brackets and made some minor adjustments to the inner seat belt bracket.
10 Feb 2015 (1 hour, total time to date: 1630.0 hours)
I repeated the process described yesterday on the right side armrest. Then, I replaced the seat bottom in the cockpit and sat in the cockpit to get a better idea where to place the throttle quadrant. It looks like it will need to be higher (relative to the top of the arm rest) than I originally thought.
11 Feb 2015 (2 hours, total time to date: 1632.0 hours)
I'm about ready to remove the lower center skin again so that I can ream the wing attach holes through BH73.75 & the spars. Before doing that, I wanted to locate the aileron push rod pass through holes. I cut a wooden dowel to fit, sanded one end with flat edges, drilled a centered pilot hole in the wood, & safety wired it to the attachment point in the control stick. I used my old irish friend, Trig O'Nometry to determine the amount of elevation for the hole in the skin based on the distance between the wing attach, the wing dihedral (5 degrees), and the distance between the control stick and the skin. It looks like the elevation will be approx. 0.8 in. (give and take some for the required movement of the control stick. I leveled the dowel, located the center (as best I could), and located the hole centers 0.875 in. above the level point on the skin. This turns out to be fairly close to the edge of the side doublers. Bummer :-(. I'm going to have to consider making new doublers so that I can have more material around this hole. I wouldn't care if it weren't for the fact that I have that major skin splice. I'd rather have a little more doubler available in that area so that I can add a few more rivets to help carry more load around that critical area.
I had marked the area I thought would be the pass through (in the picture), but as shown, my original "guess" was a little too high. Also, the duct tape is only there to keep the brackets for the control yoke in the proper orientation when it's off the airplane.
I had marked the area I thought would be the pass through (in the picture), but as shown, my original "guess" was a little too high. Also, the duct tape is only there to keep the brackets for the control yoke in the proper orientation when it's off the airplane.
14 Feb 2015 (3 hours, total time to date: 1635.0 hours)
I double checked the hole locations for the aileron push rods & fabricated a drilling guide from some 0.025 sheet to rest on the web of BH73.75 and the inside of the bottom skin doubler. This allowed me to be sure that both holes were located symmetrically. I drilled a #41 pilot hole, then enlarged them to #30. I then cut 5/8 holes on each side. Once finished, I removed the seat bottom, seat supports, and the bottom skin in preparation to C/S one of the -5 rivet holes (the one that is between the seat belt brackets), Then, I will be ready to ream the wing attach holes.
Hopefully, things will begin to come together. I will be taking a few days off to get some training on laying up fiberglass for a Cozy Mk IV.
Hopefully, things will begin to come together. I will be taking a few days off to get some training on laying up fiberglass for a Cozy Mk IV.
18 Feb 2015 (1 hour, total time to date: 1636.0 hours)
I C/S the center of the 3 attachment holes through the 1/8 in. doublers on each side of the web of BH99.35 (alone the rear spar). These holes fall at the vertical arm rests, and the fasteners must be flush to accommodate the seat belt brackets that I fabricated to work with the arm rests.
20 Feb 2015 (1 hour, total time to date: 1637.0 hours)
I enlarged the inside seat belt bracket attachment holes through the rear spar carry through & reamed them to 3/16 in. I did the same for the brackets.
21 Feb 2015 (2 hours, total time to date: 1639.0 hours)
I enlarged the attachment holes for the rear seat support shear clips that attach through BH99.35 and the forward shear clips for the tail cone beams to #30. I removed the seat support clips, de-greased them, and applied a light coat of primer. I have been waiting for a 9/16 chucking reamer to be delivered so that I can ream the wing attach holes. It's very important to keep these holes tight, so I want to take time to get it done correctly. I received the reamer yesterday, and spent some time drilling/reaming holes in test pieces to check the fit with my NAS 1109-22 bolts. It appears that the 9/16 reamer is slightly large for the bolts. The bolts fit easily by hand, and I can clearly see daylight around the bolt. As much as I wish I could move on with the reaming process, I will have to order another specialty reamer and try this again. I will try a 0.5615 reamer. One thing is for sure, you can't put material back once it's cut, and I don't want to be looking for over-sized bolts. I had enough trouble finding the ones I have.
23 Feb 2015 (2 hours, total time to date: 1641.0 hours)
I installed the two C/S -5 rivets between each set of seat belt brackets at BH99.35. I then replaced the rear seat support angle and installed the seven universal head -5 rivets along the rear spar carry through.
25 Feb 2015 (1 hour, total time to date: 1642.0 hours)
I received the 0.561 and 0.5615 reamers and used them on another scrap piece of aluminum. It was very difficult to avoid damaging the edge of the hole using my drill press (the chuck is not precise, and the reamer wobbles enough to cause damage). However, the 0.561 reamer seems a bit tight for the NAS 1109 bolt and the 0.5615 is a little loose (Goldilocks, anyone?). I removed the main bulkhead (BH73.75), and clamped it to the stand I built to fit the lower skin. The existing holes in the spars and carry through are perfect for the AN9 bolts I bought from Pegasus Racing, but are too tight for the NAS bolts. I'd rather use the NAS bolts, so I will continue to think this over......
26 Feb 2015 (2 hours, total time to date: 1644.0 hours)
I contacted a local machine shop and they were able to work me in today to take another look at my reaming issue for the wing attachment holes. I fabricated another test coupon from some 0.25 thick 6061 aluminum & drilled a 35/64 diameter hole for them to ream on their Bridgeport milling machine. I also brought my spars and main BH in case they could ream the holes while I was there. It turned out that the 0.561 reamer was too tight for the NAS bolts. The 0.5615 reamer worked very well for a very close fit. They verified the NAS bolts were 0.561 +/- approx 0.0002. Sean (at Phelps Metal) set up the Bridgeport and reamed all of the holes with the 0.5615 reamer.
It also looks like they will be able to fabricate my fuel tank, and I'll be able to make a few design tweaks to fit better in the fuselage. I haven't been able to get anywhere with Mustang Aeronautics as far as getting my fuel tank and canopy that I ordered in Oct 2013.
It also looks like they will be able to fabricate my fuel tank, and I'll be able to make a few design tweaks to fit better in the fuselage. I haven't been able to get anywhere with Mustang Aeronautics as far as getting my fuel tank and canopy that I ordered in Oct 2013.
27 Feb 2015 (1 hour, total time to date: 1645.0 hours)
I laid out the patterns for the replacement doublers for BH73,75. As I wrote earlier, i want to enlarge the area around the aileron push rod pass through. I started cutting out the new doublers.
28 Feb 2015 (1 hour, total time to date: 1646.0 hours)
I finished cutting out the new side doublers, lightly finished the edges, & started match-drilling the attachment holes.
1 Mar 2015 (2 hours, total time to date: 1648.0 hours)
I drilled the corners of the upper wing attach pass-through hole in each side doubler using a 3/8 in. drill bit. I then used a cut off wheel to cut the holes out. I finished the edges with a 1/4 in. drum sander and 80 grit sandpaper. I located the center of each aileron push rod pass through hole, drilled #30 pilot holes, and used a hole cutter to make the 5/8 in. holes. Finally, I rolled the lower section of each doubler to match the originals.
2 Mar 2015 (2 hours, total time to date: 1650.0 hours)
I clecoed the original doublers to the duplicates & finished match drilling the attachment holes. Some of the holes had been enlarged when I drilled out the -3 holding rivets, so I used #33 and #31 drill bits as needed to make clean holes in the duplicates. I test fit the duplicates on BH73.75 and trimmed/finished the lower edges to fit. I then clecoed the new doublers to BH73.75 & replaced the BH in the fuselage jig.
3 Mar 2015 (1 hour, total time to date: 1651.0 hours)
I made the duplicate side doublers slightly larger in all dimensions so that I could trim/finish them after the attachment holes have been drilled to final size. I didn't account for the fit between the lower stringer doublers and the lower forward edge of the side doublers. I removed the BH from the jig, removed each doubler, & trimmed/lightly finished the trimmed edges. I also did a little more light finishing around the doublers to help reduce the risk of scratching the fuselage skins. I then replaced the doublers and BH in the fuselage jig.
4 Mar 2015 (1 hour, total time to date: 1652.0 hours)
I replaced the lower center skin and splice doubler to check the fit of the new side doublers. The aft portion of each doubler interferes with existing attachment holes between the center lower/upper skins, and needs t be trimmed back. I marked the trim line and laid out possible locations for rivets to secure the doublers and add more strength to the joint.
6 Mar 2015 (2 hours, total time to date: 1654.0 hours)
Brian Smyers came over after work to help me rivet the shear clip brackets through the lower web of BH99.35. This needed to be done before I can attach the bottom skin (trying to avoid using Cherry Max rivets). I then removed BH73.75 (again) so that I could trim the side doublers & start laying out the location of the additional fasteners that will go through the skins/doublers at that major splice.
7 Mar 2015 (3 hours, total time to date: 1657.0 hours)
I finished tracing the edges of the splice doublers & center skins on the side doublers so that I could also finish the fastener layout on the new doublers. The interface between the 4 layers (side doubler, splice doubler, lower & upper center skins) complicate the process of locating the fastener holes since it is important to maintain proper fastener edge distance. In addition, I wanted to secure the area around the aileron push rod pass through holes & allow for some hole enlargement once I know exactly what is needed for the push rod. I allowed for a minimum of 0.25 in. of additional trimming (should be plenty assuming my trig was correct). I drilled the new attachment pilot holes in each side doubler and match drilled the holes in each mating component. I also enlarged the aileron pass through hole in the splice doubler (up approx. 3/16 in.) to make it easier to make adjustments to the hole once the layers are assembled.
8 Mar 2015 (3 hours, total time to date: 1660.0 hours)
I used a hole cutter to cut out the 5/8 in. aileron pass through hole in each center, side skin. I then replaced the splice doubler in the airplane & used my Dremel 1/2 in. drum sander to enlarge the aileron pass-through holes to match what I had done to the holes in the splice doublers yesterday. I replaced the bottom skin, & enlarged those holes to match. I then replaced the instrument panel & upper longerons.
9 Mar 2015 (1 hour, total time to date: 1661.0 hours)
Since I damaged one of the lower skin attachment holes along the flange of BH73.75 when drilling out a holding rivet, I needed to investigate my options. Fortunately, the damage was away from the free edge, so I tried to "walk" the hole center toward the damage as I enlarged the pilot hole from #40 to #31. The damage is still not completely removed, so it may be necessary to move up to a -5 rivet (even more reason to be glad that the damage was away from the edge). Jasson (my IA) will be coming over tonight, to look it over, and I need to come up with a plan to get the fuselage closed up. The other good thing about moving up to -5s in that local area would be to take more load out of the BH web before the lower doubler runs out. I also like the idea since there are 4 layers of material along that rivet line, and adding a couple of -5s will provide a more robust attachment along that major splice area. This will also get more load into the side doublers that can be more gradually transferred to the skins through those doublers. Also, I added one more attachment hole in the upper center skins through the side doubler. There was a "gap" between fasteners that was a bit too large to leave open. I'll match drill these through the doublers when I replace the skins.
10 Mar 2015 (1 hour, total time to date: 1662.0 hours)
Jasson came over to take a look at the airplane, and we discussed the tasks remaining before the remaining skins can be closed. He agreed that I should take the damaged hole up to a -5 rivet. In fact, we agreed that I should move 3 of the holes up to -5 on each side. The lowest hole in the flange will remain as a -4, but the next 3 above it will be -5s. This helps to equalize the load in each rivet moving up the fastener line since the first rivet tends to take more load (if all are the same size). Enlarging the next holes will attract more load to these fasteners and allow this load to be transferred more evenly through the side doubler into the lower and upper side skins. We also discussed the use of washer head and pan head structural machine screws along the bottom of the BH73.75 flange and between the wing attach lugs. The washer head fasteners are lower profile, but will also strip more easily. I plan to use these only in areas where we have enough room and clearance to turn the nut. On the sides, the profile is not an issue, so pan heads make more sense. On the outside ends of the lower flange, there is little clearance.
11 Mar 2015 (1 hour, total time to date: 1663.0 hours)
I was unable to find #6 structural machine screws to attach the skins along the bottom of BH73.75 and between the wing attach lugs. Therefore, I'll be using #8 screws. I removed the bottom skin (once again) to double check the edge distance for the fastener holes. There's about 10/32 edge distance, so edge distance won't be an issue. I started replacing the right side skins.
13 Mar 2015 (2 hours, total time to date: 1665.0 hours)
I finished replacing the right side skins so that I could drill out the skin attachment holes through the flange of BH73.75 just below final size (I'll ream them the rest of the way right before riveting). I know I'll have to remove the skins one or two more times, and I want to keep the cleco damage out of the final assembly. I'll use Boelube to capture the aluminum shavings when I ream the holes. I started with the 3 rivet holes above the wing attachment where I will be using the larger, -5 universal head rivets. I carefully walked the holes as much as I could to give me the most edge distance possible. I drilled them up to 5/32 for now, but will take them up to #22 soon (I don't have a #22 bit right now). The damage at the lower hole is almost removed, so the final ream should be good.
14 Mar 2015 (2 hours, total time to date: 1667.0 hours)
I continued drilling out the fastener holes along the flange of BH73.75 and the right side doubler. I had some difficulty with the lower hole between the wing attach lugs. It looks like I will need to take a closer look at it once I remove the skins. I also match drilled #41 pilot attachment holes long the lower right stringer.
15 Mar 2015 (3 hours, total time to date: 1670.0 hours)
I replaced the left side skins & started drilling out the attachment holes along the left flange of BH73.75.
16 Mar 2015 (1 hour, total time to date: 1671.0 hours)
Finished drilling out the attachment holes along the left side of BH73.75. I also wrapped a cargo strap around the forward skin in preparation to drill out the lower attachment holes at BH73.75.
17-19 Mar 2015 (4 hours, total time to date: 1675.0 hours)
The cargo strap didn't do a lot of good - mostly because I didn't want to over-tighten it. Also, it was very difficult to access the lower fastener holes (even using an angle drill). I wanted to be sure to get these holes lined up well. I managed to open up the holes near the outside, but decided to wait until I removed the BH again and drill these holes with the BH up-side down. I used a strap duplicator to drill the attachment pilot holes through the the center and forward skings at the upper longeron at BH73.75. I went over the attachment holes along the side doublers to get them up to 1/8 in. Some will be dimpled and some won't. Any locations with 4 layers of material will not be dimpled. Finally, I removed the skins (again) and BH 73.75. I examined the fastener holes between the wing attach fitting, and verified that I had double-drilled one of the holes on the right side (the lower one). I will need to open this hole for a #10 fastener, so I will do both sides the same way.
Before removing the main BH, I determined how to position the tunnel and center bottom skin with the BH clamped inverted on the wooden jig shown in the photograph. I want to be sure to have these parts oriented the same as they are on the airframe.
Before removing the main BH, I determined how to position the tunnel and center bottom skin with the BH clamped inverted on the wooden jig shown in the photograph. I want to be sure to have these parts oriented the same as they are on the airframe.
20 Mar 2015 (1 hour, total time to date: 1676.0 hours)
I attached the bottom skin & tunnel to the bottom of BH73.75 & verified the alignment. I started replacing the forward side skins
21 Mar 2015 (1 hour, total time to date: 1677.0 hours)
Finished replacement of the forward skins (including trimming the bottom edges flush to the tunnel flanges), Then, I trimmed the seat back support to lay in place against the web of BH99.35. I will have to do more work on the support, but will wait until I decide how I will attach it to the BH. It must be removeable for access, but I want to consider my options before running ahead of myself.
28 Mar 2015 (2.5 hours, total time to date: 1679.5 hours)
I drilled out the attachment holes along the fore and aft ends of the bottom doubler (through the tunnel and bottom skins). Along the bottom skin, I drilled them out to 1/8 since they will be dimpled, and at the tunnel, to #30 since I will use standard head rivets). My forward side skins wrap around to pick up more fastener holes at the bottom of BH73.75 and cover the tunnel sides. I haven't finished trimming that transition, and the left side was blocking one fastener hole through the front of the side doubler. I used a drum sander to remove some of the material to allow access to this hole. Also, I made a cardboard template as a pattern for the wrap-around, and marked both sides for later trimming. Finally, I drilled out the holes along the bottom of BH73.75 to #21 in stages (#29, 9/64, 5/8, and #21). Once the hole was up to #21, I used a 0.162 chucking reamer to finish each hole for a nice fit for the #8 machine screws. I did one hole at a time so that there would be no movement until I could replace a -5 cleco back in the hole.
29 Mar 2015 (2.5 hours, total time to date: 1682.0 hours)
I removed the forward side skins, trimmed, & finished the edges along the tunnel, transition under BH73.75 (main BH), & the aft edge (to provide the final edge distance for the fasteners along the main BH flange. Then, I removed the tunnel, center bottom skin, and bottom doubler. I trimmed/finished the bottom doubler to provide clearance to buck the attachment rivets along the tunnel flange.
30 Mar 2015 (1 hour, total time to date: 1683.0 hours)
I drilled out the lower attachment holes between the wing attach fittings to #13 (these are the holes that had been damaged earlier) through the side doubler and flange of BH73.75. I then removed each doubler and match drilled these holes through the lower center skin and forward side skins. I then replaced the BH in the fuselage jig and checked to see whether the lower center skin could be installed with the lower doubler in place. I was considering the idea of riveting nut plates inside the lower flange through the doubler, but this doesn't look promising because there is space available to squeeze the nut plate rivets only in the central area of the lower flange (about 4 holes). I'll stick with the standard nuts and try using a hemostat to get them started. This is the kind of thing that you don't think much about until the time comes. :-)
31 Mar 2015 (1 hour, total time to date: 1684.0 hours)
I trimmed the lower corners of the heavy aluminum angle braces that run between the wing attachment lugs on BH73.75 (main BH). The corners of the braces were in contact with the bottom and forward side skins - causing some scratching to occur. I cut the corners back & finished the edges. Then, I replaced the BH in the jig & started work replacing the skins once again to go over all of the attachment holes prior to final finishing and installation of the bottom skin.
1 Apr 2015 (1 hour, total time to date: 1685.0 hours)
I continued replacing the skins. I had to cut notches in the seat back flange to accommodate the splice doubler flange on each side. I also replaced the upper longerons and IP.
3 Apr 2015 (2 hours, total time to date: 1687.0 hours)
After replacing the right center skin, I match drilled the attachment holes that had been filled by holding rivets between the splice doubler and bottom skin. I also located & drilled two more attachment holes at the aft end of the skin (where I have wrapped the skin below the splice) to provide more strength at the transition between the tail cone & the side/bottom skins. I then replaced the right forward skin & used a hole finder to locate the hole through the upper longeron at the center/forward skin splice. I started reaming the remaining holes along the skin splice to final size (these holes will not be dimpled).
4 Apr 2015 (3 hours, total time to date: 1690.0 hours)
I finished reaming the holes along the right, forward/center skin splice to their final size. Then, I checked the existing attachment holes in the right center skin by running a 1/8 inch drill bit through each one that will be dimpled. The holes in the lower skin through the side doubler will not be dimpled, so I also reamed them to #30. I then back-drilled the attachment holes through the forward end of the upper longeron through the forward skin to 1/8. (these holes in the skin will be dimpled). I also drilled out the attachment holes through the forward end of the right side doubler and forward side skin to 1/8 inch. Then, I removed the right side skins to provide better access to the left side. I replaced the left center skin & repeated the process I used on the right side.
5 Apr 2015 (3 hours, total time to date: 1693.0 hours)
I replaced the left forward skin & repeated the process used on the right side to drill/ream out the holes along the main BH flange and left side doubler. I removed the side skins and started working on the seat bottom to get it ready for final installation. I drilled out the attachment holes between the seat bottom supports and seat bottom BH to 1/8 in., clecoed the supports on the BH, replaced the assembly on the seat bottom, & drilled out the seat support attachment holes through the bottom skin.
6 Apr 2015 (1 hour, total time to date: 1694.0 hours)
I measured & trimmed the fiberglass seat back to separate the upper end (above the shoulder harness), and to fit around the existing structure/fasteners around the bottom flange of BH99.35. I plan to make a cover for the upper part of the seat back to enclose it (to carry some baggage, i.e. clothing), and attach a head rest. The lower area will allow for a parachute & padding as needed. I also drilled 2 attachment pilot holes to secure the lower portion of the seat back.
I will also need to fabricate an angle brace to fit between the upper longerons (supporting the upper seat back) & design it to serve as the attachment point for the shoulder harness. I like this location better than the top of the tail cone because the longerons provide a more substantial attachment, & the harness mounted lower will help hold my body (head) down in case the plane would ever flip over in a crash. It should also keep me snug & secure in the seat for aerobatics.
I will also need to fabricate an angle brace to fit between the upper longerons (supporting the upper seat back) & design it to serve as the attachment point for the shoulder harness. I like this location better than the top of the tail cone because the longerons provide a more substantial attachment, & the harness mounted lower will help hold my body (head) down in case the plane would ever flip over in a crash. It should also keep me snug & secure in the seat for aerobatics.
7 Apr 2015 (2 hours, total time to date: 1696.0 hours)
I drilled out the attachment holes around the seat BH flange to 1/8 in. Then, I replaced the arm rest supports ( I needed to trim the left one slightly), & drilled out the attachment holes through the bottom skin. I bolted the seat belt brackets in place, replaced the seat bottom, & drilled out the seat bottom attachment holes to 1/8 in. These will be drilled/reamed/dimpled for #8 machine screws later.
8 Apr 2015 (1 hour, total time to date: 1697.0 hours)
I laid out the remaining 4 attachment holes for the fiberglass seat back flange & double checked the placement on the flange of BH99.35. I drilled #30 pilot attachment holes in the seat back, & replaced the seat back on the BH. Thw seat back required more trimming to fit with the arm rests in place. I then replaced the seat back & match drilled the pilot attachment holes.
9 Apr 2015 (1.5 hours, total time to date: 1698.5 hours)
I drilled/reamed the attachment holes on the seat bottom to 0.1620 in 3 steps (5/32, #21, then 0.1620). I removed the seat bottom & de-burred the new holes.
10 Apr 2015 (1.5 hours, total time to date: 1700.0 hours)
I removed the arm rests, removed the protective plastic, & de-burred the holes. Then, I removed the seat BH/supports, removed the remaining plastic, & de-burred /finished all three components.
11 Apr 2015 (1 hour, total time to date: 1701.0 hours)
I removed the splice doublers & bottom skin. I started removing the protective plastic from the bottom skin and began de-burring the attachment holes in the skin.
17 Apr 2015 (2 hours, total time to date: 1703.0 hours)
Removed the remaining plastic from the bottom skin & finished de-burring the holes. I trimmed/finished the skin around the forward end (around the lower wing attachment cut-out) to get rid of some unnecessary material. I also removed a little more material from the left rear vertical bracket at BH73.75 to provide more clearance with the bottom skin.
18 Apr 2015 (3 hours, total time to date: 1706.0 hours)
I used a pneumatic disk sander to make a few final tweaks to the forward & aft edges of the bottom skin. I then finished the edges with fine sand paper & scotch brite. I used my C-frame dimpler to dimple the attachment holes along the bottom of the skin. I'll have to put the skin back on jig & dimple the holes around both radii with my rivet gun. Fortunately, I will be able to do them myself since they are easy to reach. I dimpled the holes at each splice using my rivet squeezer. Finally, I removed the plastic on each splice doubler, de-burred the holes/edges, and dimpled the holes.
19 Apr 2015 (5 hours, total time to date: 1711.0 hours)
I replaced the bottom skin, bottom, & splice doublers on the fuselage jig. I used my rivet gun to dimple the remaining attachment holes in the bottom skin. Then, I also used the rivet gun to seat the dimples between the splice doublers and the bottom skin. It is virtually impossible to get 3 layers of dimpled skin to seat properly when installing rivets when the holes are dimpled with the same die. I removed the parts & went over the surfaces with scotch brite to prepare them for etch/alodine. Then, I cleaned the parts with acetone before using the PPG de-greaser to prepare the parts for the acid etch. I etched/alodined the parts. When dry, I applied a light coat of primer to the mating surfaces of the doublers.
20 Apr 2015 (2 hours, total time to date: 1713.0 hours)
I applied a light coat of primer to the inside mating area of the bottom skin and BH99.35. I also de-greased and applied primer to the outer skin at BH99.35. I then removed the main BH from the fuselage jig, & removed the side doublers for finishing. I removed the plastic and tape that I had used to protect the parts & de-burred the attachment holes, cut-outs, and edges. Finally, I polished the edges, cut-outs, & lightly buffed the surfaces with scotch brite.
21 Apr 2015 (2 hours, total time to date: 1715.0 hours)
I de-burred the attachment holes in the flange of BH73.75 & dimpled the appropriate holes in each side doubler. I then degreased, etched, & alodined the doublers.
23 Apr 2015 (2 hours, total time to date: 1717.0 hours)
I applied a light coat of primer to the mating surface areas of the doublers and seat bottom. I then replaced the main BH, doublers, & seat bottom back on the fuselage jig. Hopefully, this will be the last time these parts will be removed.
26 Apr 2015 (1 hour, total time to date: 1718.0 hours)
Started enlarging the attachment holes between the IP & BH73,75 web to 1/8 in. (I'll ream them out to #30). I also enlarged the pilot attachment holes between the lower IP & the angle stiffener. I replaced the upper longerons so that I could drill through the attachment clip at the top of the BH web (my angle drill came in very handy there).
27 Apr 2015 (1 hour, total time to date: 1719.0 hours)
I reamed the IP attachment holes to #30 along the flange of BH73.75. I then removed the lower portion of the IP (my modification) so that I could add two more attachment holes between the lower IP and the 0.062 thick 1x1 angle stiffener. I removed the stiffener, de-burred the existing holes, marked the new hole locations & drilled the pilot holes. I replaced the stiffener & match drilled these holes through the IP.
29 Apr 2015 (1 hour, total time to date: 1720.0 hours)
I marked and trimmed the 0.062 angle stiffener to provide clearance for instruments in the lower IP. I then finished the edges of the angle & replaced it on the lower IP.
30 Apr 2015 (1.5 hours, total time to date: 1721.5 hours)
I drilled out the new attachment holes through the lower IP to 1/8 in. & replaced the lower IP on the airplane. I then drilled out the attachment holes along the lower edge of each removable panel to 1/8 in. Finally, I removed each panel & drilled out the attachment holes between the panel stiffener frames and the lower IP (these are covered by the panels). I removed the lower IP and did some light de-burring of the holes in the lower IP.
1 May 2015 (1.5 hours, total time to date: 1723.0 hours)
I did a little more finishing work on the lower IP angle stiffener to provide more clearance for instruments. Then, I fabricated a cardboard template for a seat back support to fit across the upper longerons. I can use a 1.5x1.5x0.062 angle to serve as the support & mounting point for the shoulder harness. I traced the template on the angle stock & cut the angle to size.
2 May 2015 (2 hours, total time to date: 1725.0 hours)
I finished the ends of the angle & marked the bend lines to allow the ends of the seat support to seat properly on the upper longerons. I bent the ends slightly between two pieces of hard wood & checked the fit. It took a few iterations to get the proper fit. Finally, I marked the ends along the inside edge of the longerons & marked the location for two fasteners (allowing for 0.375 in. edge distance). I drilled #41 pilot holes in each end of the support.
3 May 2015 (4 hours, total time to date: 1729.0 hours)
I replaced the seat back support angle on the upper longerons, replaced the seat back, & clamped the angle in place against the seat back. I used my angle drill to match drill the attachment pilot holes through the longerons. I then progressively match drilled out the attachment holes to #21 (using clecos to hole the angle in place at the intermediate steps) from the bottom. I then drilled one hole out to #13 & reamed it to 0.188 so that I could install an AN-3 bolt to hold it in place. I then repeated this process on the remaining 3 holes. This was a time consuming process since the holes are very close to the tail cone skin, and I was very careful about keeping as much edge distance as possible. The edge distance on the longerons ended up at approx. 0.325 in. , but since the longerons are twice the thickness of the support angle, this won't be a structural issue.
Finally, I went back to work on the IP structure. I dimpled all of the holes in the lower IP, and C/S the corresponding holes in the stiffening angle. I also re-squeezed all of the holes I could reach with my pneumatic squeezer to set the dimples inside each other (and in the C/S stiffener). I have a few more to set in the IP panels, but will have to do that with my rivet gun tomorrow.
Finally, I went back to work on the IP structure. I dimpled all of the holes in the lower IP, and C/S the corresponding holes in the stiffening angle. I also re-squeezed all of the holes I could reach with my pneumatic squeezer to set the dimples inside each other (and in the C/S stiffener). I have a few more to set in the IP panels, but will have to do that with my rivet gun tomorrow.
4 May 2015 (1.5 hours, total time to date: 1730.5 hours)
I set the remaining dimples between the IP panels and the lower IP. Then, I removed the seat back support, upper longerons, & the IP. I de-burred the attachment holes in the IP and flange of BH73.75. I dimpled the holes in the two IP attachment brackets, replaced the IP, & set these dimples to be sure they were nested completely.
5 May 2015 (1.0 hours, total time to date: 1731.5 hours)
I de-greased, etched, & alodined the IP parts (lower IP, stiffening angle, & attach brackets).
6 May 2015 (2.0 hours, total time to date: 1733.5 hours)
Brian Smyers (work colleague) came over to help me rivet the bottom center skin to BH99.35. We couldn't get to the fasteners near the vertical rear spar carry through supports (fuselage jig). I kept the additional support in place on the bottom of the tail cone, but before I remove the vertical supports, I will wait until I have side skins clecoed in place to help ensure that nothing moves.
I then C/S the remaining fastener holes in the upper longerons.
I then C/S the remaining fastener holes in the upper longerons.
8 May 2015 (1.5 hours, total time to date: 1735.0 hours)
I replaced the IP structure, upper longerons, & seat back support. Then, I replaced the seat BH & supports so that I can prepare to lay out the location of the throttle quadrant. I also marked the side skins for trimming.
9 May 2015 (3 hours, total time to date: 1738.0 hours)
My brother, Bill, came over today. I trimmed the side skins, removed the plastic from the edges, finished the side skins & de-burred the attachment holes on the left side skin. Bill de-burred some of the holes as well. I then dimpled the appropriate holes in the left side skin so that I could replace it on the airplane.
14 May 2015 (3 hours, total time to date: 1741.0 hours)
I replaced the left side skin on the airplane in preparation to fit the throttle quadrant bracket/arm rest. Then, I did a little more trimming on the right side skin (I found a few more places that needed it). I finished the edges (again), and de-burred the fastener holes. Finally, I dimpled all of the appropriate holes in the right side skin and put it aside for now.
15 May 2015 (1 hour, total time to date: 1742.0 hours)
In order to lay out the location for the throttle quadrant on the inside of the left skin, I decided to make a mounting fixture using a piece of scrap 1/2 in. plywood and some 0.032 sheet material. The plywood provides clearance for the nuts/nut plates on the back of the quadrant, and the sheet material can be attached to the plywood to provide the required attachment to the fixture. I started work cutting/finishing the plywood & sheet material to size. I then located the attachment holes in the plywood and drilled them out to #12.
16 May 2015 (3 hours, total time to date: 1745.0 hours)
I located the quadrant attachment holes in the sheet material & drilled them out to #12. I also had to cut out a notch along the bottom edge of the plywood/sheet material to accommodate the nut plate in the quadrant. I drilled #30 attachment holes through the sheet/plywood to secure the sheet to the plywood. I then drilled out the holes in the plywood to 5/8 in. to allow clearance for a 3/8 socket for the AN3 nuts. I dimpled the #30 holes and squeezed rivets inside the plywood to secure the sheet and allow the quadrant to sit flush in the fixture. I replaced the arm rests, seat supports, & seat bottom in the lower skin so that I could sit in the airplane and check the location of the quadrant. It took several attempts to get the location that was comfortable and would work with the hardware.
17 May 2015 (3 hours, total time to date: 1748.0 hours)
I can't proceed with the throttle quadrant until I have the throttle cable and can lay out the cable run and figure out how I'm going to secure the throttle end of the cable. I'd like to attach a bracket on the aft side of the web of BH73.75, so I need to know how far the quadrant needs to be from the BH for everything to work. I ordered a cable from A/S (A-920) that will probably be too long for the throttle, but may be OK for the mixture. If not, I hope I can return it and order a custom length.
So, with this on hold, I decided to work on the tunnel. I need to drill out the attachment holes to the firewall BH and the forward side skins. I replaced the right side skin so that I can also replace the forward side skins at the overlap at BH73.75. I also had to dimple the attachment holes in the tunnel along the forward end of the lower doubler. I removed the protective plastic around these holes in the tunnel, de-burred the holes & the aft edge, and dimpled these holes. Once the holes were dimpled, I replaced the tunnel on the air frame. I drilled out the attachment holes along the rudder pedal reinforcement & lower stiffener at the firewall. In the process, I realized that I needed a spacer between the tunnel sides and the vertical angle at the firewall to take up the space below the attachment flange for the tunnel floor. I cut/finished the spacers & inserted them between the tunnel sides and the angle. I used some duct tape to hold them temporarily and match drilled the attachment holes. I'll have to epoxy the spacers in place on the tunnel sides later.
So, with this on hold, I decided to work on the tunnel. I need to drill out the attachment holes to the firewall BH and the forward side skins. I replaced the right side skin so that I can also replace the forward side skins at the overlap at BH73.75. I also had to dimple the attachment holes in the tunnel along the forward end of the lower doubler. I removed the protective plastic around these holes in the tunnel, de-burred the holes & the aft edge, and dimpled these holes. Once the holes were dimpled, I replaced the tunnel on the air frame. I drilled out the attachment holes along the rudder pedal reinforcement & lower stiffener at the firewall. In the process, I realized that I needed a spacer between the tunnel sides and the vertical angle at the firewall to take up the space below the attachment flange for the tunnel floor. I cut/finished the spacers & inserted them between the tunnel sides and the angle. I used some duct tape to hold them temporarily and match drilled the attachment holes. I'll have to epoxy the spacers in place on the tunnel sides later.
18 May 2015 (1.5 hours, total time to date: 1749.5 hours)
I replaced the left and right forward skins and used a strap duplicator to drill the aft attachment pilot holes through the side skins. I had been debating this because there was not enough material to attach the tunnel sides to the floor at the aft end, and it didn't make a lot of sense at the time to drill the attachment holes to the side skins aft of that point. However, since the side skins will be secured to the lower stringers and the flange of BH73.75, the skin will be able to support the aft tunnel sides and help seal out exhaust gasses (with the additional help of pro-seal). Now, I wish I had done this earlier since it was much more difficult to locate these holes with the tunnel in place on the air frame.
19 May 2015 (1 hour, total time to date: 1750.5 hours)
I drilled out the attachment holes along the tunnel flange to 1/8 in. in two steps. These holes will be dimpled. Next, I plan to check the fit of the rudder pedals. When I sat in the airplane to fit the throttle quadrant, my legs were resting uncomfortably on the main spar carry through. I want to see how things are with my feet on the pedals. I may need to install a piece of angle stock on the tunnel floor as a heel rest to keep my knees bent enough to keep my legs off of the carry through.
20 May 2015 (1 hour, total time to date: 1751.5 hours)
I sat in the airplane again to check the fit of the rudder pedals, and I'm still not sure if I'm going to need to add anything to the tunnel floor. No need to rush, so I'll keep thinking it over. I also removed the forward side skins & the left center skin in preparation to rivet the three attachment holes at either end of the lower center skin and BH99.35.
Yes, I know that I'm holding the stick with the wrong hand, but I had to use my "right" hand to take the picture. :-)
Yes, I know that I'm holding the stick with the wrong hand, but I had to use my "right" hand to take the picture. :-)
21 May 2015 (1.5 hours, total time to date: 1753.0 hours)
Brian Smyers came over to help me rivet the remaining holes in the bottom skin and BH99.35. I never removed the support I placed under the tail cone (when I removed BH99.35 for dimple/de-burring), so that was a BIG help keeping things in place. We removed the rear spar vertical jig supports one at a time (staring on the right) to gain access to the 3 holes that were blocked by each support. The side skin also helped to hold everything in position, but the opposite skin needed to be removed to allow easier access to buck the rivets. I know that the plans call for this skin to be a single piece, but as Mr. T would say, "I pity the fool that has to crawl in there (or lean over the side) to buck those bad boys." It was much easier to do it my way. Once those rivets were finished, I got everything back to "normal." I had to get those rivets in before I could think about installing the seat/arm rest supports in the bottom skin.
22 May 2015 (2.0 hours, total time to date: 1755.0 hours)
I'm still waiting on the A-920 throttle cables from A/S, so I decided to work on the seat supports. I removed the side seat support angles from the arm rest supports & dimpled the holes for the #8 C/S screws. Then, I removed the seat BH and center seat supports. I did a little more finishing work on the parts as well, and dimpled the seat attach holes in these parts. Finally, I started drilling out the nut plate attachment holes in the center seat supports. I finished drilling the holes in the right center support and started on the left.
23 May 2015 (4.0 hours, total time to date: 1759.0 hours)
Finished drilling the nut plate attachment holes in the left center seat support and continued drilling the nut plate attachment holes in the side seat supports as well as the seat BH. The only good way I found to drill these holes was with my angle drill since the flange on the opposite side was blocking access. Once this was finished, I decided to go ahead and get all of the structure attached to the seat BH ready for assembly. This includes the center supports and the brackets that provide lateral support to the arm rests. I reamed the attachment holes through the center supports to #30 & progressively drilled/reamed the bracket supports. Then, I did a little more finishing work on the parts. Finally, I de-greased, etched, & alodined the parts.
24 May 2015 (1 hour, total time to date: 1760.0 hours)
I applied a light coat of self-etching primer to the mating surfaces of the parts I finished yesterday and started installing the nut plates. Since there are so many nut plates to install, I decided to use the C/S cage for the NAS1097-3 rivets.
25 May 2015 (3 hours, total time to date: 1763.0 hours)
I finished installing nut plates in the seat BH & center seat supports. I then riveted the arm rest support brackets and center seat supports to the seat BH.
I will also need to cut pass through holes through the seat BH for cables/wiring.
I will also need to cut pass through holes through the seat BH for cables/wiring.
26 May 2015 (2 hours, total time to date: 1765.0 hours)
I located and cut two, 0.75 in. dia. pass through holes in the seat BH between the rudder cable pass-thru and the arm rest bracket on each side. I then started work to locate and drill pass through holes through the lower web of BH99.35. The cables/wiring will pass through the space between the center and arm rest supports below the seat. I made a cardboard template to fit inside the lower BH web, then made an aluminum template so that I can use it as a drilling guide for the pilot hole. I want to leave as much material as possible around the lower flange and enough room near the rear spar carry thru to allow a hole bushing to fit. I definitely don't want to touch the rear spar carry thru, but will have to drill the holes from the forward side. I located the hole, and drilled a #30 hole in the template.
27 May 2015 (1 hour, total time to date: 1766.0 hours)
I used duct tape to hold the pass-thru template in position on the lower right web of BH99.35 & double checked the clearance with the rear spar carry-thru. It looked good, so I match-drilled the pilot hole from the font side, then used my 3/4 in. hole cutter to cut the pass-thru. I repeated the process on the left side. I simple turned the template over since both sides are symmetric. Then, I laid out the potential location for wiring pass-thru holes at BH73.75. Since I plan to install a radio stack between my legs, the logical place for the pass-thru holes are on either side of the C/L behind the control stick mount. I can attach Adel clamps to under the existing nuts for the lower wing attach fittings to secure the wire bundles and run them over to each side of the plane.
28-30 May 2015 (3 hours, total time to date: 1769.0 hours)
I fabricated a mock-up of the fuel tank using the RamBoard cardboard material to check the fit. I needed to use a 1 in. thick piece of form to hold the shape of the tank. I've been waiting for over 18 months to get a fuel tank from MA, and despite a phone call telling me that the tank was nearly ready, I'm not convinced that it's on the way. If I do it myself, I can make any little adjustments that may be needed, and can do it on my schedule. I'll need to get the welding done, but I can do the rest of the work. It looks like I will need to tweak the dimensions a little to make it a better fit and allow me more flexibility in how I secure it. I'm also not so sure about the advertised 15 gal. capacity, but I haven't tried to estimate the actual volume yet. It's probably a good thing that I've been planning on adding small reserve tanks in the wings.
Note: I estimated the tank v0lume, and it is indeed 15 gallons (231 cubic in./gallon). :-)
Note: I estimated the tank v0lume, and it is indeed 15 gallons (231 cubic in./gallon). :-)
31 May 2015 (1 hour, total time to date: 1770.0 hours)
Brian Smyers came over and helped me rivet the seat BH and center seat supports to the lower, center skin.
1 Jun 2015 (1 hour, total time to date: 1771.0 hours)
I replaced the armrest supports, flap control quadrant, & seat bottom so that I could sit in the airplane and check out the fit and clearance of the fuel tank mock-up. It looks very good. I also started work fitting the flap push/pull rod brackets on the flap control torque tube.
2-3 Jun 2015 (2 hours, total time to date: 1773.0 hours)
I checked the fit of the brackets & marked the position for each bracket (orientation and spacing on the torque tube). The dimensions on the drawing did not match the situation on my lower skin (looks like a slight difference in the bottom curvature). My biggest concern is the clearance between the bolt head and bottom skin for the push rod attach bolts. The maximum clearance I can get is 10/32, but I think that will be plenty. It is possible for the torque tube to slide left/right in the attachment tubes since the quadrant bracket can flex a little, but not enough to be a real problem. I installed the spring and internal tube that provides the catch at each flap setting. Unfortunately, the spring traveled around the turn in the flap control handle, so I will need to fish it back out and buy another spring to take up that space. I can't think of a better solution right now. I also removed the push tube brackets & drilled the attachment holes out to #21 on one side in order to use them as drilling guides when I put them back on the torque tube for final drilling/reaming.
4-5 Jun 2015 (2 hours, total time to date: 1775.0 hours)
I replaced the right flap control bracket on the torque tube, aligned it to 10 degrees behind the actuator handle, & drilled out the attachment hole through the torque tube to #13. I then reamed the hole to 0.188 in. & inserted an AN3 bolt to hold it in place. I then repeated the process for the left side, but used the right side as a guide so that they would match. Once finished, I removed the brackets, cleaned them up, & coated the insides of the parts with corrosion protective oil.
I also cleaned up the edges of the slotted tube that fits inside the flap control arm so that it would move more freely along the notched in the flap control quadrant.
I also cleaned up the edges of the slotted tube that fits inside the flap control arm so that it would move more freely along the notched in the flap control quadrant.
6 Jun 2015 (2 hours, total time to date: 1777.0 hours)
I removed the flap control brackets from the torque tube & de-burred the holes through the tubes. I decided to use a short section of a 5/8 in. dia. tension spring (~0.4 in.) to prevent the compression spring from sliding down the corner of the flap control handle. I could have inserted a short piece of 5/8 steel tubing to do the same thing, but I'm hoping the spring won't rust as quickly. Either way, I'll be spraying some corrosion inhibitor inside at each annual. I assembled the compression spring, the rest of the components, and replaced the flap control in the airplane. Everything works fine.
7-9 Jun 2015 (4 hours, total time to date: 1781.0 hours)
I returned my attention to the fuel tank. The weld-in fittings from Aircraft Spruce require a fairly large cut-out (~1.125 in.) and have a raised flange. This makes it very difficult to stick with the plans version of a 1 inch wide flat section at the bottom of the tank. I found a different fitting on-line that appears to be easier to use. It requires a 1 in. hole. I also didn't like the way the plans call for a 2-piece bottom that is welded along the C/L. So, I'm back at the drawing board making more cardboard mock-ups. Since I need a little over 2 inches flat at the fitting, I'm going with 2.75 in. to allow me to make both bends with my bench brake. Since this is wider, I need to increase the pitch of the bottom to allow enough clearance under the tank and provide better support. The bend in the bottom provides stability/support for the weight of the fuel. I tried 22.5 degrees, but it was too much, so now I'm looking at 14 degrees on the fuel tank bottom, version 3.0. :-)
10-12 Jun 2015 (3 hours, total time to date: 1784.0 hours)
I made new fuel tank templates to look at the fit for a 14 degree angle at the bottom. I clamped the pieces together & laid it in place. It looked better, but I needed to sit in the plane to be sure that I would be able to get in easily. I replaced the seat bottom and went for a "test drive." It looked good, except my toes were very close to the bottom of the tank when I simulated using the brakes. I also noticed that the outside bottom edge was not level (which follows from the height being more in the front - per plans). I need to count on about an inch above the tank to allow for:
vent line,
space above the filler cap (I plan to install a hinged cover on the top skin), and
room for the fuel probe head.
I fabricated the top so that it has uniform spacing between the BHs. I'm sure I'll have to adjust the curvature of the actual part, but it looks like I have a good template to work with. I decided to shorten the height of the forward side by 0.25 inches to get it nearly level and give me a little more toe clearance. Since the back is wider, the bottom slopes down anyway. The only other point I want to mention is the about length of the tank. If I allow 1 inch clearance in the front (for brake fluid reservoirs & water separator for the fuel vent), there's not a lot of room behind the IP (about 4.5 inches for a 15.5 in long tank). Less than you'd expect since the IP is canted forward. I'm sure I'll be cutting it back to around 15 in., but I may need a little flange for welding the ends. At the back side, each inch is > 1 gallon, so there's a bit of a trade-off to consider. Finally, I marked up one of my 0.032 thick sheets of 5052H32 aluminum for the tank bottom.
vent line,
space above the filler cap (I plan to install a hinged cover on the top skin), and
room for the fuel probe head.
I fabricated the top so that it has uniform spacing between the BHs. I'm sure I'll have to adjust the curvature of the actual part, but it looks like I have a good template to work with. I decided to shorten the height of the forward side by 0.25 inches to get it nearly level and give me a little more toe clearance. Since the back is wider, the bottom slopes down anyway. The only other point I want to mention is the about length of the tank. If I allow 1 inch clearance in the front (for brake fluid reservoirs & water separator for the fuel vent), there's not a lot of room behind the IP (about 4.5 inches for a 15.5 in long tank). Less than you'd expect since the IP is canted forward. I'm sure I'll be cutting it back to around 15 in., but I may need a little flange for welding the ends. At the back side, each inch is > 1 gallon, so there's a bit of a trade-off to consider. Finally, I marked up one of my 0.032 thick sheets of 5052H32 aluminum for the tank bottom.
13 Jun 2015 (3 hours, total time to date: 1787.0 hours)
I cut/finished the edges of the tank bottom. I bent the side flanges first, then made the lower 14 degree bends for the bottom flat area. I then bent the sides up approx. 76 degrees. I say approximately, because it's pretty hard to get that exactly right. I know I'll be making some adjustments later. Finally, I laid out the pattern for the top, cut and finished the edges.
14 Jun 2015 (3 hours, total time to date: 1790.0 hours)
I started forming the curvature of the tank top, then bent the flanges. My thinking was that I'd get a better handle on the angle I needed for the flange bend. Well, it would have been easier to make the flanges first & bend them to about 60-70 degrees. Anyway, after some trial fits, I needed to make adjustments to the bends in the tank bottom. I did that by replacing the part in the bending brake, clamping it in place, & using a scrap piece of 2x4 to apply even pressure along the edges to open up the bend as needed. In other cases, I needed to add a little more bend. It took a few times, but I was finally happy with the result. Then, I made adjustments to the top. The issue there was to be sure I had a little over an inch clearance (especially over the aft end where the fuel sender head will go). The flange joint for the tank sections has to be above the stringers because I need to use all of the space from side to side for fuel (also, the fact is that I made the tank so that it fits very closely between the stringers). I'll be cutting back the flanges for welding, but there still wont be enough clearance for the flanges. This is where the time with the cardboard templates really paid off. It is much better to waste cardboard - as I did making three attempts. In the end the tank looks like a good fit. :-)
15 Jun 2015 (2 hours, total time to date: 1792.0 hours)
The man (John Perkins) who I've asked to weld my tank asked me to provide him with some scrap pieces to work with since the material is so thin (0.032). I took some time to fabricate 3 pieces that duplicate the types of welds he will be doing. One was a butt flanged joint, another was a flange on the skin (internal baffle), and the last was a hole in a piece of skin with a spar weld-in fitting. I also started working on the dimensions of the internal baffle. I plan to cut a template from some 3/8 plywood.
16-21 Jun 2015 (8 hours, total time to date: 1800.0 hours)
I got a bit "behind" in my documentation. Over the last several days, I cut & finished a plywood form for the internal baffle for the fuel tank. Then, John asked me to fabricate a small version of the tank so that he could see if there might be any complications before he starts welding the actual tank itself. I really appreciate that, given the amount of time I've got into the tank. I fabricated a 6x6x6 in. "mini" tank. I have a little more work to do on it, but it's mostly complete. The other good thing for me is that it gave me some practice on making the end caps.
Also, I received my fuel sender and gauge.
Also, I received my fuel sender and gauge.
22-26 Jun 2015 (6 hours, total time to date: 1806.0 hours)
After checking the clearance between the top of the tank and the upper skin as well as the fit between the upper stringers, it looked like it was going to be too close for comfort. I need a little over an inch for the fuel sender, and I don't have the elbows for the vent line and fuel transfer. So, I decided to re-do the tank top to allow a little more room. I took 1/8 in. off each side and gave that a try. Unfortunately, that resulted in more clearance than I really wanted - bummer. Then, using the Goldilocks approach, I tried it again with 1/16 off each side. I know it seems like nothing, but it matters. It's good to have the templates to keep everything else the same when making these adjustments. I also took a little more time to check the alignment of the top and bottom since it's easy to get the bends off slightly. I also had to spend more time working the plywood baffle fixture to get the fit to work. The baffle will hold the shape so that I can fit the end caps later. This is really quite a bit of work, and I'm very happy that I will not have to try to weld the tank myself. It's disappointing (again) that I couldn't count on MA to deliver the tank, but this way, I can make adjustments to suite my requirements.
For anyone else building a MM, The tank really limits the space behind the IP more than you may realize before you get it in position. The canted IP makes this even worse. I had thought about cutting the top portion of the tank and bending the end cap, but that would make it more difficult to seal. So, the better alternative (IMO) is to trim the entire back at an angle to provide a little more room behind the panel. I plan to cut back about 1.75 in. at the top and leave the bottom alone. This will minimize the loss in tank volume and retain a flat end cap. Because of the other minor changes I made to the bottom, I should still have 15 gallons (maybe a little more).
For anyone else building a MM, The tank really limits the space behind the IP more than you may realize before you get it in position. The canted IP makes this even worse. I had thought about cutting the top portion of the tank and bending the end cap, but that would make it more difficult to seal. So, the better alternative (IMO) is to trim the entire back at an angle to provide a little more room behind the panel. I plan to cut back about 1.75 in. at the top and leave the bottom alone. This will minimize the loss in tank volume and retain a flat end cap. Because of the other minor changes I made to the bottom, I should still have 15 gallons (maybe a little more).
27 Jun - 1 Jul 2015 (5 hours, total time to date: 1811.0 hours)
I cut a piece of 3/8 plywood to fit in the forward end of the fuel tank as a form to make the forward end cap. It took a little while to get it sanded to final shape (with the baffle form in place to hold the proper overall shape). The fit was excellent. Then, I rechecked the upper curvature of the baffle form and did some work to "tweak" that fit. I glued some shims along the top edge and filled the gaps with wood filler. Once dry, I lightly sanded the filler & applied more glue to the filler to keep it from cracking and falling off. Once that was dry, I finished the sanding & re-checked the dimensions of the baffle on the aluminum sheet. Finally, I laid out the bend lines and holes in the baffle.
Also, I did a little work on the throttle quadrant. I finally received a push-pull cable from A/S and can now lay out the location of the quadrant on the center side skin. I have to come up with a good way to secure the cable using the notch in the assembly. It looks like I'll be able to secure it at the web of BH73.75.
Also, I did a little work on the throttle quadrant. I finally received a push-pull cable from A/S and can now lay out the location of the quadrant on the center side skin. I have to come up with a good way to secure the cable using the notch in the assembly. It looks like I'll be able to secure it at the web of BH73.75.
2 Jul 2015 (1 hour, total time to date: 1812.0 hours)
I cut out the holes around the perimeter of the fuel tank baffle using a cut-off wheel on my die grinder. I just didn't think that buying a large hole cutter was worth the expense - these openings don't need to be precise by any means. I did some minor finishing to remove the irregularities of the cuts. Finally, I bent the side flanges.
3 Jul 2015 (5 hours, total time to date: 1817.0 hours)
I continued work on the fuel tank baffle. I cut/finished the inside oval holes in the baffle. I decided to make the holes to allow me to use angle stiffeners across the width and avoid flaring these holes. I really didn't want to buy a flaring tool just to flare two holes - or buy a 5 in. hole cutter for that matter. I used my fly cutter to cut 2, 3.75 in dia. holes 1 in. apart (using a piece of wood clamped to the baffle to locate the hole centers for the fly cutter). I then bent the bottom flanges using pieces of hard wood on each side of the baffle. I had to cut another piece of wood to match the upper curvature of the tank in order to bend the upper flanges. I wasn't sure how many cuts would be required on the upper flanges to accommodate the curvature. I bent one practice piece of aluminum to find out. I was able to make the bend with a single cut. I also used this practice piece to find out how to taper the cuts. I clamped the baffle between the new wood form and the plywood baffle form to make the flanges (using a hard rubber mallet). I then cut 2 strips of the tank material (5052H32) to make angle stiffeners for the baffle. I finished the edges and bent the angles. I laid out the fastener holes, drilled the holes, and match drilled them on the baffle. I sized the internal holes to allow the stiffeners to fit across the width. Finally, I de-burred the holes, dimpled, and riveted the stiffeners on the baffle.
4 July 2015 (2 hours, total time to date: 1819.0 hours)
I made the flanges a bit wide to make the bending easier, and give me a little room for error. It's always easier to cut material off than put it back. I cut the flanges to 0.5 in. wide and punched 3/32 attachment holes. I then replaced the baffle, verified the position/alignment, and match drilled the attachment holes through the flanges.
5 July 2015 (1 hour, total time to date: 1820.0 hours)
I replaced the left side skin to start working on the throttle quadrant. Now that I have the push-pull cable, I know how far the quadrant has to be from BH73,75 (to secure the cable). I laid out the location and sat in the airplane to check the operation and fit.
6 Jul 2015 (1 hour, total time to date: 1821.0 hours)
I continued working on the throttle quadrant. I worked up a design to secure the cable on BH73.75. The pass-thru hole is just over 3/8 in. I located/drilled the first hole though the BH web and enlarged/finished it to final size.
7-10 July 2015 (3 hours, total time to date: 1824.0 hours)
I cut/finish/bent a piece of scrap aluminum 0.032 sheet to duplicate the location of the main BH web so that I could check the push-pull cable pass through holes and the attachment method. I also fabricated test pieces for the interlocking attachment method using 0.032 aluminum. I plan to use steel for the actual parts, but this will give me a way to verify that it will work. Everything looked good as far as securing the cables, but the angle was a bit too severe for the cable run to the quadrant. I re-located the quadrant (raised it slightly and reduced the angle). Now, it seems fine. I was also concerned about the pass thru hole for the mixture, but it looks fine as well.
11-12 Jul 2015 (5 hours, total time to date: 1829.0 hours)
I worked on the front end cap of the fuel tank and the throttle quadrant installation. I cut out the blank for the front end cap. The plans call for 2, 3/4 in. beads on each end cap. I cut 3/4 in. strips from some scrap 3/8 plywood and made male forms for the beads. I also made a smaller practice piece to see how it worked using my flush rivet set on my rivet gun. I clamped down the practice sheet(s) (yes, I tried it twice). It was a disaster. I'm going to have to re-think this and get back to it later.
I also cut and fabricated mounting angles for the throttle quadrant. One will span the upper end, and a smaller angle will attach to the top of the upper angle to secure the upper quadrant bolts. I'll use nut plates on this angle.
I also cut and fabricated mounting angles for the throttle quadrant. One will span the upper end, and a smaller angle will attach to the top of the upper angle to secure the upper quadrant bolts. I'll use nut plates on this angle.
13 Jul 2015 (2 hours, total time to date: 1831.0 hours)
I went back to my local sheet metal shop to talk about bead rolling the end caps for my fuel tank. Rob was very helpful, and told me that he would be able to bead the parts. I needed to cut the blank for the aft end of the tank so that I could bring them both to the shop. Before cutting the aft blank, I needed to cut the aft end of the tank to allow uniform space behind the IP. I made the cuts and lightly finished the edges. Then, I marked, cut, & finished the edges of the aft cap blank. Finally, I marked the areas of the blanks for beads and cut out two practice pieces to take to the shop.
14 Jul 2015 (2 hours, total time to date: 1833.0 hours)
I wasn't able to reach Rob this afternoon, so I resumed work on the throttle quadrant attachment. I laid out the rivet pattern along the top edge of the angle that will attach to the upper rail. This smaller angle will mount directly to the upper quadrant bolts, so I needed to verify that the nut plates will clear these attachment holes. I drilled these 5 pilot holes along the top edge of the smaller angle, and followed up by match drilling these holes to the upper rail (angle) that will be riveted to the side skin. Then, I took the quadrant apart so that I could duplicate the quadrant back plate. I fabricated 2 duplicates from 0.040 thick 2024-T3. The purpose of the duplicate is to attach to the front of the quadrant so that I can secure a cover over the quadrant. I will be installing a control arm behind the quadrant to reverse the direction of the elevator trim control input from the prop control on the quadrant. This will need to be covered, and the installation will be much cleaner with a cover anyway.
15 Jul 2015 (1 hour, total time to date: 1834.0 hours)
I called Rob this morning and arranged to bring my fuel tank end caps to his shop for beading. Sean was able to do it for me (see image). I also laid out and drilled the attachment pilot holes in the upper rail for the throttle quadrant. These holes are for attachment to the left side skin.
17-18 Jul 2015 (4 hours, total time to date: 1838.0 hours)
I did more work on the fuel tank end cap forms. I don't know exactly how the form needs to fit in each end so that the caps will fit properly after I bend the flanges. I sanded/beveled the plywood forms to fit in each end, then sanded them down a little more to account for the thickness of the caps. Since they are beaded, I needed to cut out the center of the form to fit on the male side of the beaded skin. I cut out the other form for the front cap and used a reciprocating saw to cut out the center. Then, I cut another aluminum end cap blank to use as a practice piece to be sure it would fit. I also cut notches for the flanges - I wanted to check to be sure I could get the curved edge flange to form properly. I then clamped the practice piece between the forms and formed the flanges with a hard rubber mallet.
19-20 Jul 2015 (4 hours, total time to date: 1842.0 hours)
The practice end cap was slightly big, so I worked on the plywood forms to get a better fit on the beaded blank. I put the practice piece back between the forms and used the mallet to re-form the upper curve. This made a much better fit. Then, I re-marked the beaded blank for trimming, cut, and finished it again. I cut the stress relief notches in the piece (just as I did on the practice piece since they worked well). I placed the blank between the forms and bent the flanges around the circumference. The difference in this piece is the beading which caused an issue with "flatness" of the part. I was hoping that the flanges would help the problem, but the notches allow the part to deflect out of plane. It was extremely difficult to fit this part on the tank. You want a reasonably tight fit, but the out of plane movement made for a problem. I had to work my way around the edges carefully and punch 3/32 holes to cleco the cap in place. This was very frustrating and I considered throwing the whole thing in the trash. I don't want to go into the airplane fuel tank fabrication business. I can only hope that the welder won't have a lot of trouble with the thin skin and any warping.
21 Jul 2015 (2 hours, total time to date: 1844.0 hours)
I marked/cut/finished the second plywood form for the bead side of the rear fuel tank end cap. Then, I cut out another practice blank & formed it with a plastic mallet. The fit looks good.
22 Jul 2015 (4 hours, total time to date: 1848.0 hours)
A lot of progress today. I fabricated a cover for the fuel probe opening so that it would hold the area flat and allow me to seal the tank without the fuel sender installed. The hole pattern (standard SAE 5-hole) was a bit of a challenge to duplicate since I didn't want to drill through the tapped flange that came with the sender. I ended up enlarging the holes a little, but that won't make any difference. I took some time to lay out the locations of the filler neck and bung holes for the fuel inlets, vent, and outlet. I plan to have a right/left inlet for the wing tanks. I cut all of the holes in the tank and put things back together.
24-26 Jul 2015 (7 hours, total time to date: 1855.0 hours)
There was a lot more work needed before the fuel tank could be given to the welder. I re-checked the fit of the practice rear end cap & made a few slight adjustments to the plywood forms. I decided to rivet the fuel probe backing plate to the upper tank skin. There is no easy way to hold the plate in place once the tank has been closed. The plate is notched so that it can be inserted in a finished tank by cutting a slot in the tank. This leaves less room for a good seal and is a bit convoluted. Also, you have to remember to use long bolts to keep the plate from falling in the tank if you ever have to remove the fuel probe. So, I took the time now to eliminate these concerns. I drilled 4 pilot holes in the plate (the notch in the plate prevented the use of 5 rivets). I bolted the plate in place & match drilled #40 holes through the steel plate. I removed the plate, dimpled the holes in the skin, & C/S the holes in the plate. I then de-greased the plate & applied a very light coat of high temperature enamel to the mating side of the plate (I have no idea how hot it may get during welding since it's close to the upper bungs). Then, I started work on the real, rear end cap. I cut the stress relief notched around the flange, clamped the cap between the forms, & used my plastic mallet to form the flanges. I fit the cap in place using my hole punch to allow me to cleco it in place. The beads caused more problems (just like I had in the forward cap). The the cap was warped, so it didn't want to stay flat without some persuasion. I attached the top & bottom edges, & worked my way around each side. I used a pair of vice grips with duct tape over the jaws to hold the flanges in place as I worked my way around. When finished, I removed the end cap & replaced all of the clecos with #4 machine screws (easier for the welder). Then, I replaced the rear cap & used screws to secure it. I taped the bungs in place to give everything to the welder.
27 Jul 2015 (2 hours, total time to date: 1857.0 hours)
I cut two pieces of 0.125 thick 6061 aluminum to use as grounding strips for the fuel tank. I wanted to use 2 on each side of the tank (at the front) to help hold the tank in place as well as provide a very good ground to the air frame/engine mount. I cut the strips 0.875 wide and drilled 3/16 holes on one end. I finished the edges and will deliver them with the tank to be welded in place. Then, I turned my attention to the avionics rack to be placed between my legs on BH73.75. I wanted to check the fit under the tank before it is gone to the welder. I plan to place one radio and transponder in this location and will need approx. 4.25 in. of height for mounting the radios. This allows for 0.5 in. attachment on each end and some clearance for cooling. I also made them 11 in. long to provide some isolation from the fuel tank overhead. I fabricated a test piece from cardboard and glued them together to check the fit.
28 Jul 2015 (1 hour, total time to date: 1858.0 hours)
I handed off the fuel tank to the welder. Now, I've got my fingers crossed. :-) They plan to have it ready by next week.
I resumed work on the radio stack installation. I laid out the position of the center panel and mounted the radio stack mock-up in the panel to check the dimensions and clearance with the fuel tank location.
I resumed work on the radio stack installation. I laid out the position of the center panel and mounted the radio stack mock-up in the panel to check the dimensions and clearance with the fuel tank location.
29-31 Jul 2015 (4 hours, total time to date: 1862.0 hours)
While waiting for my fuel tank to be welded, I continued working on the radio stack and the throttle quadrant. I cut two strips of scrap aluminum to mount the radio stack mock-up to check the fit. I need to provide clearance for the fuel line/shut-off valve and the top of the stack. This means that the stack will have to be angled back more than I had originally thought. The good news is this will make it easier to add a support to the back of the stack off the tunnel floor. I spent some time trying different options.
I also fabricated mounting angles for the throttle quadrant. Since my engine already has mounting hardware for the throttle cable, I had to be sure that I had the proper throw on the engine side of the cable. I had measured this before, but I didn't want to drill any holes in the skin until I was comfortable with the location. Just to be clear, I'm using a 3-lever quadrant because I am using the prop control lever for the elevator trim. I'll have to reverse the action to make it more intuitive, but the location is better because it's awkward to get my left hand much further aft.
Finally, I got a call from the sheet metal shop. My tank is welded, but they didn't weld the grounding straps (waiting for me to verify where I wanted them). I stopped by and took a look at the tank. It warped around the filler neck, but I don't think that could be avoided because of the 0.032 thick aluminum skin. It won't show anyway, but I hope the neck turns out to be vertical.
I also fabricated mounting angles for the throttle quadrant. Since my engine already has mounting hardware for the throttle cable, I had to be sure that I had the proper throw on the engine side of the cable. I had measured this before, but I didn't want to drill any holes in the skin until I was comfortable with the location. Just to be clear, I'm using a 3-lever quadrant because I am using the prop control lever for the elevator trim. I'll have to reverse the action to make it more intuitive, but the location is better because it's awkward to get my left hand much further aft.
Finally, I got a call from the sheet metal shop. My tank is welded, but they didn't weld the grounding straps (waiting for me to verify where I wanted them). I stopped by and took a look at the tank. It warped around the filler neck, but I don't think that could be avoided because of the 0.032 thick aluminum skin. It won't show anyway, but I hope the neck turns out to be vertical.
1 Aug 2015 (3 hours, total time to date: 1865.0 hours)
I fabricated the mounting brackets for the lower portion of the throttle quadrant. I'm using the same system as I used for the upper mounting bolts. Once I had them finished, I replaced the quadrant, and match drilled the holes through the bottom mounting bracket and left side skin.
2 Aug 2015 (2 hours, total time to date: 1867.0 hours)
I fabricated a plate (using some scrap 0.040 in. thick 2024-T3) to fit over the front face of the throttle quadrant. I want to install a cover over the quadrant as well as the cables/mechanisms for the throttle, mixture, and elevator trim. The plate will attach through the existing AN3 bolts for the quadrant and allow the covers to attach to it around the sides. Since the quadrant is securely attached to the left side skin, it will serve as a good point of attachment for the covers. It also must allow access to the cable ends for maintenance.
3 Aug 2015 (1 hour, total time to date: 1868.0 hours)
I picked up my finished fuel tank. I need to test it, but it looks good. I also resumed work on brackets to support the cover for the throttle quadrant.
4 Aug 2015 (1 hour, total time to date: 1869.0 hours)
I drilled pilot attachment holes in the cover attachment strip that will fit along the inside, left flange of BH73.75. I then clamped the strip on the flange, marked the pilot holes through the strip, & double checked the hole location on the flange (there was not a lot of room for error). I made a slight adjustment, marked the desired position, & match drilled the pilot attachment holes through the strip.
5-9 Aug 2015 (6 hours, total time to date: 1874.0 hours)
I cut/fit the forward cover panel for the throttle quadrant, & fabricated a 0.040 thick aluminum doubler and a steel duplicate as a template to install around the push-pull cable pass-thru holes in BH73.75. I will use the template to match drill the attachment holes through the BH and use it as a reference for the cable retention plates. I cut the pass thru hole in BH73.75 for the mixture cable, & match drilled the upper and lower doubler holes in the BH. I fabricated the 0.050 thick steel cable retention plates. This required a few iterations before I was satisfied. The retention system resembles a "key hole" to allow the cable to pass thru, then the plates are shifted to capture the notch that is built into the cable end. The holes (0.375+ and 0.25) are drilled in the plates, but I still need to trim the key hole between the holes.
10-11 Aug 2015 (3 hours, total time to date: 1877.0 hours)
I cut the "key-ways" through the cable retention plates, & finished the edges with a 1/4 in. Dremel drum sander. I decided to re-fabricate the double from a piece of 0.050 thick 2024-T3 sheet so that I could C/S the doubler and avoid dimpling the powder coated BH web. I finished the new doubler and match drilled the pilot attachment holes through the BH web. I also drilled the pilot holes for the AN3 bolts that will hold the retention plates in plate on the BH. As a result of this process, I had to change the location of some of the attachment holes in the new doubler. The old doubler is in the picture to the left.
12 Aug 2015 (1.5 hours, total time to date: 1878.5 hours)
I progressively drilled out the two attachment holes through the cable retention plates, doubler, and BH73.75 to #13. I then reamed the holes to 0.188 for a close fit for the bolts. The process was a little complicated since drilling the holes through the steel was best done on my drill press, so after each step, I replaced the doubler on the BH to match drill & finally those holes. Once this was done, I trimmed/finished the steel. The "horns" on the outside plate will facilitate installation/removal. I could drill more holes in the plates to save a little more weight. I'll think this over...
13-16 Aug 2015 (8.5 hours, total time to date: 1787.0 hours)
I C/S the -4 rivet attachment holes in the push-pull cable pass-thru doubler, drilled the nut plate attachment holes, & match drilled the nut plate holes in BH73.75. I then C/S the nut plate holes in the doubler. I did more finishing work, de-greased, etched, & alodined the doubler. I applied a light coat of primer. Once cured, I riveted the doubler in place.
Then, I returned to work on the throttle quadrant cover. I clamped the forward 0.032 cover in place & fabricated the top that fits in front of the quadrant. This part was a little tricky because it tapers forward slightly since the 3-lever quadrant is a little wider than the BH flange. Once I was happy with the fit, I laid out/drilled the pilot attachment holes along the front edge of the front cover. I'll be using #6 machine screws to attach the covers, so I opted for approx. 2 in. hole spacing. I match drilled these pilot holes though the attachment strip on the BH flange, then laid out the attachment holes to the new top. I then match drilled those holes.
Then, I returned to work on the throttle quadrant cover. I clamped the forward 0.032 cover in place & fabricated the top that fits in front of the quadrant. This part was a little tricky because it tapers forward slightly since the 3-lever quadrant is a little wider than the BH flange. Once I was happy with the fit, I laid out/drilled the pilot attachment holes along the front edge of the front cover. I'll be using #6 machine screws to attach the covers, so I opted for approx. 2 in. hole spacing. I match drilled these pilot holes though the attachment strip on the BH flange, then laid out the attachment holes to the new top. I then match drilled those holes.
17 Aug 2015 (1 hour, total time to date: 1788.0 hours)
I laid out the attachment holes around the forward and lower edges of the throttle quadrant, drilled the pilot holes through the cover, & match drilled them through the quadrant attachment plate. Not too shabby.
18-21 Aug 2013 (4 hours, total time to date: 1792.0 hours)
I want to install mag switches and a push button started near the throttle quadrant, so I fabricated a cover to fit horizontally in front of the quadrant. I started with a cardboard template to get the dimensions dialed-in, then made the part with some scrap 0.032 2024-T3 sheet. It took some time to get the cover trimmed to fit well since the angles are not square. I also wanted it to angle more toward me. This has the added benefit of more clearance between the left skin for drilling the attachment holes (also for installing/removing the fasteners later). I then, made the attachment bracket to install on the left skin. Because of the skin curvature, I needed to form the bracket to fit using fluting pliers. Once I had it finished, I laid out the fastener hole locations for the skin, drilled the pilot holes, taped it to the skin, & match drilled the holes through the skin.
22 Aug 2015 (2 hours, total time to date: 1794.0 hours)
I made a few adjustments to the attachment bracket to allow the cover to fit a little better. I needed to add a little more to the bend and trim/finish the lower edge to clear the lower cover. Then, I laid out the fastener locations to allow the most available space for the switches, drilled the pilot holes in the new cover, taped/clamped it in place, & match drilled the holes on each side of the cover. Not too bad :-)
23-24 Aug 2015 (2 hours, total time to date: 1796.0 hours)
I returned to the radio stack. I cut/finished the sides from 0.050 thick 2024-T3. I am using this thickness so that I can C/S machine screw holes for radio installation. This section will be removable and will slide in and out of the center lower panel (I still need to design/fabricate it). Then, I cut the upper/lower covers, and bent the flanges. Finally, I laid out and drilled pilot attachment holes along one edge of one of the side panels.
25 Aug 2015 (1 hour, total time to date: 1797.0 hours)
I drilled the remaining attachment pilot holes on the top and bottom edges of both side panels, I then cut and bent angle stiffeners to attach to the upper/lower radio stack covers.
26-27 Aug 2015 (2 hours, total time to date: 1799.0 hours)
I cut the angle stiffeners to fit, & laid out the fastener holes. I drilled the pilot holes in the stiffeners, then match drilled the holes in the upper/lower covers. I cut 2, 2x4 blocks to use as spacers for the radio stack. I cut the spacers just under 4 in. to provide room for a radio and transponder with some space for cooling between them. I cleco clamped the parts together with the spacers, & match drilled the pilot attachment holes through the upper/lower covers. The picture shows the result next to the cardboard prototype. This will slide in/out of the center stack to make it easier to install the radios.
28-30 Aug 2015 (8 hours, total time to date: 1807.0 hours)
I finished the radio stack stiffeners, dimpled the attachment holes, & alodined the parts. I riveted the stiffeners to the upper/lower covers. Then, I assembled the box, & drilled out the attachment holes for each side to #30. I finished the sides/attachment holes, & C/S the holes in the sides. Finally, I riveted the sides to the covers.
31 Aug 2015 (2 hours, total time to date: 1809.0 hours)
The "stock" control stick from MA is too long to work with my lowered IP. I know I'm not the first builder with this issue, but I needed to come up with something else. I bent some pieces of conduit to try a few ideas that would fit comfortably. Also, I wanted to keep in mind that it is advisable to have that forward bend to avoid being impaled by the stick in the event of an emergency landing. Also, the longer stick allows for more movement at the grip for better control, so I'll go as long as possible. Full forward travel appears to go beyond the plane of the IP (with the forward bend), so I wanted to try to move the grip (from Aircraft Spruce) back as far as possible since I'm planning on having a center panel for radios/fuel gauge/ fuel shut-off. I don't want to be slamming my fingers on the panel. I made 3 versions and tried them on for size. The second is shown above. It's a little short, but the grip extends about 4 inches above the top of the tube, so it's a little deceiving. My third attempt is shown here, but I think I'll do a little more experimenting before finalizing the plan.
1-2 Sep 2015 (2 hours, total time to date: 1811.0 hours)
I bent one more piece of conduit to see if I could see much difference in the fit for the stick. There really wasn't much difference, so it may work out just as well to have a 1 inch O.D. piece of tubing welded to the stock stick after cutting it to the proper length for the grip. I took the parts to a welder and explained what I wanted. Hopefully, he will have it finished soon, and I will see how it works. Worst case, he can cut it shorter & weld another bent tube to it. Then, I returned to fitting the radio stack. I wanted to have a good idea how the center panel needs to fit to allow clearance for the stick at full travel. In flight, I know there is very little stick travel, but I still need to be sure to have this clearance.
3-4 Sep 2015 (4 hours, total time to date: 1815.0 hours)
Well, I got the stick back and the weld looks great. However, he didn't do what I asked. I wanted the 1 inch tube welded just forward of the bend in the stick, but he cut it off below the bend and welded the adapter so that the stick was straight, and it ended up a little short. Lesson learned, I guess. I checked it out in the airplane, and it is a bit awkward and comes back into my stomach. I'll have to make new prototypes with more conduit and see how this can be fixed. Next time, I'll go back to my friends in Dayton.
I continued work on the radio stack. I fabricated 2 brackets from 0.125 thick aluminum angle stock to attach to the upper main spar carry through, drilled 4 pilot attachment holes in each, and took my time to locate it on the cap. I will attach aluminum plates on either side to support the radio stack. To allow clearance for the fuel shut-off valve, the stack is at a pretty steep angle. It works out to point right to my line of sight. I'll need to install a mounting system on the tunnel floor as well and run angle (rails) on each side. Finally, I cut two 0.062, 1 x 1 angles to attach to the lower angle of the IP to support the upper end of the radio stack. I finished the edges and drilled 2 attachment pilot holes in each.
Note: The radio stack is going to limit access to the forward fuselage, so I thought about options to make it removable. Once I install the fuel gauge, and other things above the radios, this really doesn't seem like a workable option. The tank itself is a pretty big obstacle anyway. I want to have decent access to the rudder pedals/brake lines/fuel tank support, so it looks like the better option would be to add an access panel on the tunnel floor between the lower radio stack and the rudder pedals. I'll have to consider this carefully...
I continued work on the radio stack. I fabricated 2 brackets from 0.125 thick aluminum angle stock to attach to the upper main spar carry through, drilled 4 pilot attachment holes in each, and took my time to locate it on the cap. I will attach aluminum plates on either side to support the radio stack. To allow clearance for the fuel shut-off valve, the stack is at a pretty steep angle. It works out to point right to my line of sight. I'll need to install a mounting system on the tunnel floor as well and run angle (rails) on each side. Finally, I cut two 0.062, 1 x 1 angles to attach to the lower angle of the IP to support the upper end of the radio stack. I finished the edges and drilled 2 attachment pilot holes in each.
Note: The radio stack is going to limit access to the forward fuselage, so I thought about options to make it removable. Once I install the fuel gauge, and other things above the radios, this really doesn't seem like a workable option. The tank itself is a pretty big obstacle anyway. I want to have decent access to the rudder pedals/brake lines/fuel tank support, so it looks like the better option would be to add an access panel on the tunnel floor between the lower radio stack and the rudder pedals. I'll have to consider this carefully...
5-7 Sep 2015 (10 hours, total time to date: 1825.0 hours)
I fabricated/fit the upper brackets (1 x 1 x 0.062) for the radio stack support. I also attached a piece of 0.040 thick aluminum between the brackets to accommodate a terminal block for avionics. I then cut/finished the side supports for the radio stack from 0.062 thick 2024-T3 aluminum. To get the IP ready for final installation, I drilled the nut plate attachment holes for the #6 machine screws along the lower edge of the main panel. I then C/S the holes & installed the nut plates in the lower IP.
A friend (Rod) came over to help me rivet the bottom skin doubler to the lower center skin. I had to drill out one bad rivet (my fault), so we'll have to re-do that hole later.
A friend (Rod) came over to help me rivet the bottom skin doubler to the lower center skin. I had to drill out one bad rivet (my fault), so we'll have to re-do that hole later.
8-11 Sep 2015 (5 hours, total time to date: 1830.0 hours)
After thinking it over, I finally concluded that I will use #8 machine screws to attach the radio stack brackets to the main spar carry through cap. It will make assembly much easier, and I'll go ahead and use #8 screws at the top as well. Again, I doubt that I'll ever remove it once the airplane is finished, but it does leave the option open. I drilled the pilot attachment holes in the brackets/cap out to #21, then reamed the holes to final size for the screws. Then, I removed the upper longerons (hopefully for the last time) so I could remove the IP. It was simply much easier to rivet the IP together off the airplane. I finished the new parts for the upper radio stack attachment, then etched, alodined, & primed the mating surfaces of the brackets. I riveted the IP together & replaced it on the airplane (along with the longerons). Now, I'm finally ready to rivet the IP to BH73.75.
12 Sep 2015 (4 hours, total time to date: 1834.0 hours)
Wow, it took a lot longer than I thought (what a surprise) to rivet the IP to the main BH. I had to remove the left side skin & do some trimming/finishing to the lower aft flange of the upper stringers. It was just as well since those corners are just hanging out there and aren't carrying any load. I still couldn't reach the last two rivets at the top of the BH flange - the longerons block access. After trying everything I could think of, it looks like I have a few options.
1) Buy or borrow an offset rivet set, 2) Use Cherry Max rivets, or 3) Open the holes to #29 and install #6 machine screws.
A little more thinking to do.....
1) Buy or borrow an offset rivet set, 2) Use Cherry Max rivets, or 3) Open the holes to #29 and install #6 machine screws.
A little more thinking to do.....
18-19 Sep 2015 (4 hours, total time to date: 1838.0 hours)
I laid out & drilled 3 pilot attachment holes in the lower radio stack brackets for the sides, and fastened them to the main spar carry through using #8 machine screws. I clamped the sides to the upper/lower brackets, & match-drilled the attachment holes through the brackets. I then removed the sides & drilled two attachment holes through the upper end of the sides. I re-attached the sides & match drilled the upper attachment holes through the sides. I replaced the radio stack to check the fit.
I'm planning to use a J-3 Cub fuel valve since it is certified and is more "heavy duty." I'd hate to have to replace a leaking valve anytime soon. It also comes with a lever that I can use to connect to a push-pull control above the radio stack. The catch here is that everything needs to fit properly. The J-3 valve extends lower (it's larger & requires an extra AN911 nipple union). I wanted to get the fittings installed before going any further with the radio stack. Well, in the process, I discovered a problem. The aluminum bung fittings don't allow the AN fittings to seat fully. I normally don't turn a fitting more than approx. 1 revolution past hand tight to get the alignment I need. This would not be a problem except it causes a clearance issue for me at the top and bottom of the tank. I allowed approximately 1 inch at the top of the tank to run the vent and wing tank supply lines under the top skin, so I need to get the fittings to seat fully in the bungs. At the bottom, I'd like to minimize the extension of the fittings between the tank and the radio stack & provide clearance for the shut-off lever. Now, this was something I wish I'd known in advance. I bought a 1/4 NPT tap to see if I could "fix" this problem on a spare bung fitting. It worked, but I will need to be very careful to keep metal shavings out of the tank (again, I wish I knew this earlier). After running the tap in the spare bung, the AN fitting extends about 3/16 through the bung. I may cut the fittings to eliminate this to provide as much room in the tank as possible to avoid siphoning (It's only 3/16, so I'll think it over).
I'm planning to use a J-3 Cub fuel valve since it is certified and is more "heavy duty." I'd hate to have to replace a leaking valve anytime soon. It also comes with a lever that I can use to connect to a push-pull control above the radio stack. The catch here is that everything needs to fit properly. The J-3 valve extends lower (it's larger & requires an extra AN911 nipple union). I wanted to get the fittings installed before going any further with the radio stack. Well, in the process, I discovered a problem. The aluminum bung fittings don't allow the AN fittings to seat fully. I normally don't turn a fitting more than approx. 1 revolution past hand tight to get the alignment I need. This would not be a problem except it causes a clearance issue for me at the top and bottom of the tank. I allowed approximately 1 inch at the top of the tank to run the vent and wing tank supply lines under the top skin, so I need to get the fittings to seat fully in the bungs. At the bottom, I'd like to minimize the extension of the fittings between the tank and the radio stack & provide clearance for the shut-off lever. Now, this was something I wish I'd known in advance. I bought a 1/4 NPT tap to see if I could "fix" this problem on a spare bung fitting. It worked, but I will need to be very careful to keep metal shavings out of the tank (again, I wish I knew this earlier). After running the tap in the spare bung, the AN fitting extends about 3/16 through the bung. I may cut the fittings to eliminate this to provide as much room in the tank as possible to avoid siphoning (It's only 3/16, so I'll think it over).
20 Sep 2015 (3 hours, total time to date: 1841.0 hours)
I ran a 1/4 NPT tap inside the finger strainer to allow the AN911 fitting to seat deeper to save some room under the fuel tank. I was a little concerned about hitting the solder at the interface with the screen, and as it turned out, I should have been. It's a good thing I had a spare strainer. :-) Since I bought a set of taps and dies for 1/4, 3/8. & 1/2 NPT threads, I cut one of my 1/4 taps short and beveled the end to allow me to open up the threads to get me within 2 threads of the end of the 911 fitting. That worked just fine. Then, I opened up the 3/8 NPT threads in the bottom tank bung fitting, I also opened up the threads in the upper 1/4 NPT bungs for the elbow fittings. Finally, I cut a piece of 1 x 0.035 4130 tubing to be bent for the control stick by my friends at Phillips Sheet Metal.
21-22 Sep 2015 (2 hours, total time to date: 1843.0 hours)
I took the 1 inch tubing to the shop to have it bent and started work on the elevator trim control. Because of the way the throttle quadrant control levers are designed, I wanted to reverse the direction of the lever (prop control) I'm using for elevator trim. Also, I want to be able to control the friction for the trim separately from the throttle/mixture, and the travel of this lever is only 2 inches (not enough for full travel of the trim tab). The trim needs 2.5 inches total travel, so I had to take care of that with the control reverse bell crank. I designed a candidate system and made a rough prototype to check travel and clearances. I'm not sure of the actual forces on the control, but am making an estimate based on the buckling resistance of the 0.062 dia. control cable wire (exposed 1 inch when in compression). I have a 2:1 mechanical advantage at the throttle quadrant.
23-26 Sep 2015 (2 hours, total time to date: 1845.0 hours)
I haven't had a lot of free time lately, but worked on the fuel shut-off valve & installed the fittings on the fuel tank. I used Permatex thread sealant (with the recommended surface prep) on the fittings. The close fit with the radio stack is easy to see in the photo. This is what I was expecting, and wanted to verify before finishing the radio stack installation.
I'll be out of town again for a few days and will have some time to think more about the design of the elevator trim control.
I'll be out of town again for a few days and will have some time to think more about the design of the elevator trim control.
1-2 Oct 2015 (2 hours, total time to date: 1847.0 hours)
Began work fabricating the elevator trim control quadrant. I fabricated the sides of the quadrant out of some scrap 0.040 thick 2024-T3. I finished the edges and bent the flanges on each piece.
3-4 Oct 2015 (3 hours, total time to date: 1850.0 hours)
I drilled the pilot pivot & attachment holes through the front/back of the trim control quadrant. Then, Jasson came over to help me rivet the upper longerons in the tail cone. We also riveted the two attachment holes at the top of the web at BH73.75 for the IP and the hole I drilled out at on the bottom skin doubler. Jasson also drilled out the NAS1097 holding rivets along the lower stringers.
5-9 Oct 2015 (5 hours, total time to date: 1855.0 hours)
Went back to work on the elevator trim control quadrant. I laid out the fastener hole pattern & drilled the pilot holes through the front panel. I then clamped the parts together & match drilled the holes through the back panel. I cut 2 pieces of phenolic (0.062 thick) to sandwich between the panels to provide friction for the control arm. I finished the edges, clamped them to the front panel, & match drilled the holes. I cut the control arm from scrap 0.125 thick angle stock. I cut it so that the pivot area was just over 1 in. wide, and tapered it to approx. 22/32 at the attachment points for the controls. I wanted more surface area around the pivot point where I can tighten the bolt to control the resistance. I cut 2 strips of scrap 2024-T3 (~5/8 in. x 6.75 in. x 0.050 in) to serve as the control arm between the prop control lever and the trim control arm. This was easier than fooling around with something off the shelf from A/S. I checked the arrangement with my cardboard mock-up, and the 6 in. arm works perfectly. To ensure that the strips won't buckle, I will rivet 0.125 thick shims spaced 1.5 in. apart along the arm. Finally, I used my hole cutter to make the shims (using the 3/4 cutter with a 1/8 pilot). I finished the edges using the shank of a #30 drill bit as an axle and ran the edges down on my sanding disk and scotch brite wheel. Finally, I drilled the pilot holes in the control arm strips.
10-11 Oct 2015 (4 hours, total time to date: 1859.0 hours)
I continued working on the elevator trim control quadrant. I did more finishing work on the bell crank, drilled out the fastener holes just under final size, & cut 1 in. lightening holes in the quadrant. I wanted to wait until I bent the flanges on the front plate before drilling the holes to final size. I cut a piece of 2x4 to fit inside the front plate as one side a bending block for the tabs. I trimmed the corners of the tabs, and bent the tabs using a plastic mallet while sandwiched between the bending forms. To finish the bends (there is always some spring back), I used the flanging tool I purchased from Grove-Air (shown in the picture from 2 Jan 2013) to tighten up the bend in the face flange, and a duck-billed flanging tool to finish the other tabs.
12-16 Oct 2015 (6 hours, total time to date: 1865.0 hours)
I cut two pieces of 0.032 sheet to stabilize the sides of the elevator trim control quadrant. I laid out the fastener hole locations & match drilled the holes through the flanges on the quadrant. I dis-assembled the quadrant, drilled out the holes to final size (except the holes through the front and back of the quadrant) & finished the parts. I drilled the 4 corner holes through the front and back to #21 and the center pivot hole to #13 (to be reamed to final size at final assembly). I etched, alodined, & applied some primer to the inside surfaces of mating parts. I then re-assembled the quadrant, reamed the corner attachment holes, removed the back plate, & installed nut plates for #8 machine screws. I re-assembled the quadrant & riveted the side plates. I also riveted the push-pull arm pieces together.
17-18 Oct 2015 (3 hours, total time to date: 1868.0 hours)
Fabricated attach brackets for the elevator trim control quadrant, drilled pilot attach holes, & installed the quadrant on the left skin.
23-25 Oct 2015 (6 hours, total time to date: 1874.0 hours)
I fabricated the aft cover for the throttle/elevator trim quadrant. I need it to support the aft end of the cover, and I will use it to mount the headset jacks. This will help keep the headset cord away from all of the aircraft controls. I laid out and drilled the #40 pilot holes to attach it to the left skin. Once that was finished, I started building the arm rest covers. I wanted to get them fitted to see how the inside, aft cover for the quadrants will fit. I cut, bent, finished the right armrest cover first (it was easier, since I had the right side skin off). I measured/laid out the fastener pattern along the lower right doubler flange, drilled the holes, replaced the cover, & match drilled the holes through the flange. I then repeated the process for the left side. The difference here is that it looks like I'll be able to run the aft, inside cover to attach to the arm rest. In that case, the left armrest cover will only need to cover the area aft of the quadrant cover. I will cut the left cover to fit once I have the inside cover fitted.
26-28 October 2015 (4 hours, total time to date: 1878.0 hours)
As I started to fit the aft quadrant cover, I found that it was slightly narrow along the bottom edge where it meets the left arm rest. I ended up making two more before being satisfied with the fit. I laid out & drilled the pilot attachment holes in the cover flange that will be attached to the left skin. I used duct tape to hold it in place & a long, flexible #40 drill bit to match drill the attachment holes through the skin. Once this was finished, I fabricated a cardboard template for the inside, aft quadrant cover.
29 Oct - 6 Nov 2015 (3 hours, total time to date: 1881.0 hours)
I cut the aft, side cover for the control quadrants using the cardboard template, made a slight bend in the cover to make a nice transition around the left arm rest, & finished the forward/bottom edges to fit properly. I laid out two fastener holes along the throttle quadrant flange, drilled pilot holes in the cover, & match drilled #40 holes through the flange. I removed the aft quadrant cover, located attachment holes (~2 in. spacing) along the inside flange, replaced the covers, & used my strap duplicator to drill the attachment holes in the aft, side cover. I trimmed/finished the aft edge of the side cover. Finally, I removed the left arm rest cover, & trimmed/finished the forward end to allow it to be easily removed and fit nicely with the aft quadrant covers.
7-8 Nov 2015 (4 hours, total time to date: 1885.0 hours)
I fabricated a bracket from some scrap 0.032 thick 2024-T3 to attach to the aft cover & support the top cover for the quadrants. I bent the upper flange of the bracket to match the top, cut/finished it to fit, drilled the pilot attachment holes, & match drilled the holes through the aft cover. Then, I fabricated the top cover to fit properly. This took me 3 tries before I was happy with the fit. :-) I laid out the attachment holes along the aft, front cover panel, drilled these pilot holes, & match drilled them through the top cover flange. I removed the top cover, laid out the fastener pattern along the left side skin flange, drilled these holes, replaced the top, & match drilled these holes through the flange. Finally, I drilled the #40 attachment pilot holes in the left arm rest/front cover plate along the arm rest support using my strap duplicator. I replaced the top front cover & starter/mag switch panel for the picture. The cover parts are almost ready to be finished. Once this is ready for final installation, I can rivet the left side skin on the fuselage.
9-10 Nov 2015 (3 hours, total time to date: 1888.0 hours)
I needed to connect the fore and aft quadrant cover panels below the throttle and provide some stiffness. I fabricated a bracket out of 0.025 thick 2024-T3 that would meet those requirements. The bracket will be riveted to the aft cover panel and include a tab for nut plates to attach the forward cover panel. Once I had bent the flange on the bracket, I cut it to fit around the flange that I fabricated earlier for the throttle quadrant. I laid out the fastener locations on the aft panel, drilled the pilot holes, clamped/duct taped the bracket in place, replaced the aft panel, & match drilled #40 holes through the bracket.
11-17 Nov 2015 (10 hours, total time to date: 1898.0 hours)
I have gotten a little behind on my log, so I'll summarize the work competed over the past week.
I fabricated angle stiffeners to fit along the bottom free edges of the quadrant covers and drilled the pilot attachment holes. I drilled out all of the attachment holes for the quadrant support structures through the left skin out to 1/8 in. I'll dimple these holes later. I then replaced the quadrants to decide how to mount the push-pull cable for the elevator trim tab. I tried several ideas to mount the cable, but ended up with a design to attach to the inside of the left arm rest support. I fabricated the parts, & drilled out the pilot attachment holes. The resulting part is shown here. I wanted it to be stiff enough to minimize any sloppiness in the control.
I fabricated angle stiffeners to fit along the bottom free edges of the quadrant covers and drilled the pilot attachment holes. I drilled out all of the attachment holes for the quadrant support structures through the left skin out to 1/8 in. I'll dimple these holes later. I then replaced the quadrants to decide how to mount the push-pull cable for the elevator trim tab. I tried several ideas to mount the cable, but ended up with a design to attach to the inside of the left arm rest support. I fabricated the parts, & drilled out the pilot attachment holes. The resulting part is shown here. I wanted it to be stiff enough to minimize any sloppiness in the control.
18-22 Nov 2015 (10 hours, total time to date: 1908.0 hours)
I clecoed the elevator trim cable mounting bracket to the left arm rest skin & match drilled the attachment holes out to 1/8 in. (to be dimpled later). I also drilled/reamed out the larger hole (one of the arm rest cover attachment holes) in the bracket to 0.162 to be dimpled for a #8 machine screw. I removed the bracket, the protective plastic, & finished the parts for later assembly. I then removed the left side skin & dimpled all of the attachment holes for the quadrant supports and set it aside for later attachment.
I then turned my attention to the arm rests. I drilled/reamed the arm rest cover attachment holes out to 0.162, removed the covers, & dimpled the holes in the arm rest covers. Then, I drilled the nut plate attachment holes in the arm rests & installed the nut plates. I decided to make a new bracket that provides lateral support for the aft flap quadrant. It was 0.032 thick and was a little short (hole edge distance) where it attached to the lower right side skin stiffener. I replaced it with a new piece made from some scrap 0.040 material. I drilled/reamed the holes to final size (0.062 & 0.1875), finished, etched, alodined, & installed nut plates on the part. I also drilled out the holes in the left bracket, but did not install nut plates since I will attach this side to the left arm rest support first once it is finished.
Finally, I removed the arm rest supports and began work drilling out the holes for the stiffening doublers.
I then turned my attention to the arm rests. I drilled/reamed the arm rest cover attachment holes out to 0.162, removed the covers, & dimpled the holes in the arm rest covers. Then, I drilled the nut plate attachment holes in the arm rests & installed the nut plates. I decided to make a new bracket that provides lateral support for the aft flap quadrant. It was 0.032 thick and was a little short (hole edge distance) where it attached to the lower right side skin stiffener. I replaced it with a new piece made from some scrap 0.040 material. I drilled/reamed the holes to final size (0.062 & 0.1875), finished, etched, alodined, & installed nut plates on the part. I also drilled out the holes in the left bracket, but did not install nut plates since I will attach this side to the left arm rest support first once it is finished.
Finally, I removed the arm rest supports and began work drilling out the holes for the stiffening doublers.
23-27 Nov 2015 (5 hours, total time to date: 1913.0 hours)
Finished drilling out the attachment holes for the arm rest support doublers. I trimmed the doublers as needed to provide clearance for the elevator trim cable support and eliminated portions of the doublers where they weren't needed (e.g. left side along the top where the quadrant cover attaches to the support). I removed the protective plastic from the parts & de-burred the holes/edges. I dimpled the holes for the #8 machine screws as well as the holes for the C/S rivets. I also dimpled the attachment holes in the elevator trim cable support. I drilled out the seat belt attach holes on each arm rest support out to size D. I ordered my seat belt/harness, and will wait to drill/ream the seat belt attachment holes until I verify the size of the seat belt bracket attachment holes. Finally, I located/drilled the attachment holes for the push-pull cable control mount clamp in the trim cable support.
28-29 Nov 2015 (9 hours, total time to date: 1922.0 hours)
I got a lot of work done on the smaller parts that I need to finish before I can close the center section of the fuselage. I made a small spacer to fit under the cable control clamp to provide more clearance for the cable and the bracket. I also drilled all of the nut plate attach holes in the support structure for the quadrant covers that attach to the left side skin. I took the final two elevator cable pulleys apart to finish the angles for re-assembly and mounting on BH99.35. I de-burred/finished the parts, de-greased, etched, and alodined them. I installed the nut plates in the parts, & riveted the forward support for the covers on BH73.75.
4-7 Dec 2015 (7 hours, total time to date: 1929.0 hours)
I received the seat belt & harness hardware from A/S and verified that an AN4 bolt will work for the brackets. I reamed the seat belt attach holes in the armrest structure. I then fabricated two, 0.090 thick shims to attach to the area around the seat belt attachment to provide clearance for the bracket and the inside reinforcement as well as space for the seat belt web between the bracket and the armrest. I then did the final finishing work on the center side skins, de-greased, etched, & alodined these skins. They are now ready for final installation. I match drilled the seat belt attachment hole through the shims, & drilled the nut plate holes through the shims/armrest. Finally, I disassembled the armrest structure, did the final finishing work, de-greased, etched, and alodined these parts.
8-17 Dec 2015 (9 hours, total time to date: 1938.0 hours)
It's been a bit of a rough week. We lost Mikey on 11 Dec. He was 20 years, 7 months old and is in a few pictures on this blog. He will be sorely missed. I look forward to painting this airplane with his colors.
I worked on the arm rest supports. I riveted the nut plates, and attached the stiffening doublers, seat belt brackets, and part of the push-pull cable support structure. I also assembled the rudder cable pulleys & bolted them to BH99.35.
I worked on the arm rest supports. I riveted the nut plates, and attached the stiffening doublers, seat belt brackets, and part of the push-pull cable support structure. I also assembled the rudder cable pulleys & bolted them to BH99.35.
19 Dec 2015 (3 hours, total time to date: 1941.0 hours)
I riveted the rest of the push-pull cable support structure to the left arm rest support, and riveted the seat support brackets to both arm rest supports. Because of the location of some of the seat attachment holes, I had to use cherry max rivets in a few locations. Finally, I made a template for the radio stack support to be riveted to the fuselage tunnel.
20-21 Dec 2015 (4 hours, total time to date: 1945.0 hours)
Now that that I have everything done that I wanted to do before riveting the side skins on the airplane, I returned to work on the radio stack (waiting for riveting help). I rechecked the position of the stack on the vertical supports & located 2 attachment hole locations on each side. I will be using #6 machine screws since I need to C/S them in the 0.062 thick side supports. I drilled the pilot holes in the sides, replaced the stack, & match drilled the holes. I then enlarged them to #30 for now. I then fabricated 0.040 thick brackets to mount to the tunnel to support the back end of the stack. I then drilled 5, #40 pilot attachment holes in each bracket. I will install angles along the bottom of the stack to allow the stack to slide in and out & make it easier to find the attachment holes when the airplane is finished.
Once I positioned each bracket, I clamped a 1x2 along side to hold the position, removed the stack, & match drilled the bracket attachment pilot holes through the tunnel with a 12 inch drill bit.
Once I positioned each bracket, I clamped a 1x2 along side to hold the position, removed the stack, & match drilled the bracket attachment pilot holes through the tunnel with a 12 inch drill bit.
22 Dec 2015 (1 hour, total time to date: 1946.0 hours)
I cut, bent, & lightly finished 3 pieces of 0.032 thick 2024-T3 as angle stock. I will use two as guide rails along the bottom of the radio stack, and the 3rd to run across the aft end to hold them to the proper width. This will also stabilize the brackets on the tunnel.
23 Dec 2015 (2 hours, total time to date: 1948.0 hours)
Rob at Phillips Sheet Metal in Dayton called me to let me know he had some time to help me bend the 1 inch chrome/moly tubing for my control stick modification. I went over and worked with him to get it bent, we cut the original stick about 1.75 inches above the pivot bolt tube, and Steve welded the tube adapter/modified upper stick to the lower portion of the original stick. The tubing was more difficult to bend than I thought (even with his monster tube bender). For the bigger bend, we had to feed it a little at a time to keep it from kinking too much. We ended up with a bit of a kink in one spot, but nothing to worry about. When I got the new stick home, I had to work the upper end to get it round again to slide into the 1 in. stick grip. I cut a piece of scrap 7/8 tubing, wrapped some duct tape around it, slipped it in the stick tube, and worked it round with a hammer/anvil. I then coated the inside with CorrosionX, slide the grip on, and temporarily installed in on the airplane. My thumb has decent clearance under the panel (~1/4 in.).
24-26 Dec 2015 (4 hours, total time to date: 1952.0 hours)
Went back to work on the radio stack installation. I laid out the location of the attachment holes at the aft lower end of the stack (at each support bracket on the tunnel), and drilled the pilot holes in the brackets. I replaced each bracket, & match drilled the pilot holes through the stack. I then drilled each hole out to #30. I then laid out the guide rails along the bottom of the stack, & trimmed them to fit. I marked the location for the attachment holes, drilled the pilot holes in the rails, replaced each rail, and match drilled the holes though the supports (using an angle drill). Finally. I cut/finished the cross member to fit at the end of the rails to stabilize the structure. I marked the location of the attachment holes in each rail, removed the rails, drilled the pilot holes, replaced the rails, & match drilled the holes through the cross piece.
27-29 Dec 2015 (4 hours, total time to date: 1956.0 hours)
I drilled out the radio stack attachment holes for the side pieces to #30 & marked the location above the stack where I will install 1/16 angles for attachment of a panel for the fuel gauge and fuel shut off. I removed the sides & laid out the nut plates I will use to attach the upper portion of the radio stack sides. I cut one #8 machine screw short so that I could use it to hold the nut plates in position while drilling the attachment holes. Since I have already riveted the IP in place, I had to be careful to locate the holes so that I could reach them with the gun or squeezer. There was also limited space, so I had to use a single arm nut plate on one of the holes on each side. I de-burred the holes, C/S the nut plate holes, & attached the nut plates with my rivet squeezer.
30 Dec 2015 (1 hour, total time to date: 1957.0 hours)
I located the attachment holes along the upper sides of the radio stack support for 1/16 angles. These angles will support a panel for the fuel gauge, shut-off, and related items. They will also provide additional stiffness for the stack. I drilled out the #40 pilot holes, cut 4 inch + lengths of angle, clamped the angles to the sides, & match drilled the pilot holes through the angles. Finally, I trimmed/finished the angles along the side that attaches to the supports.
31 Dec 2015 (1.5 hours, total time to date: 1958.5 hours)
I drilled the nut plate attachment holes in the radio stack box. There are 3 attachment holes on each side of the box. Two on each side support that will require C/S for the sides to avoid catching my clothes or my leg. Since the sides are 0.062 thick, #6 machine screws are the largest possible attachment option. I riveted the six nut plates in the radio box.
1 Jan 2016 (3.5 hours, total time to date: 1962.0 hours)
Continuing to work on the radio stack. I C/S the radio box attachment holes on the sides. The C/S had to go all of the way to knife-edge to accommodate the #6 screw heads (see the screws in the picture). I normally wouldn't do that, but the loads are low, and I have another attachment hole on each side at the lower bracket on the tunnel as well as the support rails along the bottom. To avoid ovulating the holes as I ran the C/S, I clamped the sides to my drill press and used it to run the C/S. I then replaced the sides and the radio box so that I could fabricate the panel above the radios. I made a cardboard template to get the dimensions correct. I cut, bent, & finished the edges of the panel. I bent a flange along the top edge for stiffness, and bent the corner to run over the top of the radio box. I needed to have clearance to remove the box, and stiffness to support the instruments and fuel shut-off. Once it was fitted, I laid out and drilled the attachment #40 pilot holes along the sides (3 each) on the panel. I replaced the panel and match drilled the holes through the 0.062 angles on each side support. I then decided that I needed to secure the panel as it turned over the radio box. This panel needs to be removable, and I would rather it was removable without removing the box. I fabricated two angle brackets from some scrap 0.040 sheet, drilled the pilot attachment holes, aligned the brackets, & match drilled the pilot holes through the panel. I still need to cut the panel shorter and install an angle stiffener along the edge. However, it will need to fit behind the face of the radio box and clear the stiffeners in the box so that the box can be removed without removing the panel. Another day ...
2-4 Jan 2016 (4 hours, total time to date: 1966.0 hours)
I made a few templates simulating the master cylinder connection to the rudder pedals. I wanted to check for the proper distance between the connection points as well as the toe travel to apply the brakes. It looks like the best distance between the attachment points is 7 inches. This keeps the pedal face vertical at the neutral position (the attachment hole in the lower cylinder mounting bracket is ~0.7 in. above the tunnel). I talked to Grove about the typical travel of the cylinder to get full braking force, and was told it was approximately 0.625 in. Since the mechanical advantage of the kit pedal is approximately 2:1, that means the pedal toe needs to move 1.25 in.
Then, I fabricated angle stiffeners from some scrap 0.040 thick sheet to fit along the front side of the stack supports. I laid out the fastener hole locations along the supports, drilled the pilot holes, clamped the angles in place, & match drilled the pilot holes through the angles. Finally, I C/S the 3 attachment holes on each of the side supports that attaches to the support rails. This will allow the side supports to be removed if necessary.
Then, I fabricated angle stiffeners from some scrap 0.040 thick sheet to fit along the front side of the stack supports. I laid out the fastener hole locations along the supports, drilled the pilot holes, clamped the angles in place, & match drilled the pilot holes through the angles. Finally, I C/S the 3 attachment holes on each of the side supports that attaches to the support rails. This will allow the side supports to be removed if necessary.
5 Jan 2016 (1 hour, total time to date: 1967.0 hours)
I drilled out the fastener holes through the front side of the supports & C/S the 18 - 1/8 in. rivet holes on each side support.
6-9 Jan 2016 (11 hours, total time to date: 1978.0 hours)
Finished the parts for the center console. I drilled out all of the holes to final size, C/S dimpled the appropriate attachment holes, removed any remaining protective plastic, de-burred/finished the holes/edges, & drilled the necessary nut plate attachment holes, and C/S them for the 1097-3 rivets. I designed/fabricated the support structure for the shoulder harness to attach to the back rest I made earlier. I used a 2.5 x 17 inch piece of 0.090 thick 2024-T3 to carry the bending moment from a potential 1500 lb ultimate load on each harness strap. I'm using AN4 bolts to attach each shoulder strap with a 6.375 in. spacing at the attachment points (~5-6 in. behind my shoulders where the straps will be ~8 in. apart). I included a 0.75 x 0.75 x 0.062 angle to stabilize the free edge of the support. Once finished, I used a scotch brite pad to prepare all the parts for alodine. I then de-greased, etched, & alodined the parts.
10 Jan 2016 (3 hours, total time to date: 1981.0 hours)
I installed the nut plates on all of the newly alodined parts (except the shoulder harness attach points), and began work assembling them. I riveted the stiffening angle on the free edge of the upper center console cover & the guide rails on the supports that attach to the tunnel floor. I decided to "dog-ear" the supports since I don't need all of that material to support the radio stack. I also re-checked the movement of the rudder pedals to verify that the 7 in. pin-to-pin master cylinder length will work for me. It looks like something close to 7 in. (+-025) will work and allow sufficient travel for applying the brakes.
11-12 Jan 2016 (2 hours, total time to date: 1983.0 hours)
I installed the AN4 nut plates at the shoulder harness attach points, riveted the attachment brackets/stiffeners on the center console sides, and began work riveting the support structure to the seat back rest support.
13 Jan 2016 (1 hour, total time to date: 1984.0 hours)
Riveted the base fitting on each console side & finished riveting the shoulder harness support/flange to the back rest.
16 Jan 2016 (2 hours, total time to date: 1986.0 hours)
I installed the back rest/shoulder harness attachment in the tail cone and designed a doubler for an access panel in the tunnel to allow easier maintenance. I started work fabricating the doubler from 0.040 thick 2024-T3. This will allow me to dimple the attachment holes. I want to use #8 machine screws for the panel, so I'd have to use very thick material (~0.090) to allow for C/S #8 holes. The forward stringers carry loads from the engine into the forward side skins, so the tunnel is not highly loaded, but does need to be stiff enough to support loading from the pedals/brakes. The 0.040 doubler will be fine for this application.
17 Jan 2016 (4 hours, total time to date: 1990.0 hours)
I continued working on the tunnel access panel doubler. I finished drilling out the #40 pilot holes in the doubler & trimmed/finished the edges. I used a 1.5 in. hole cutter to cut the inside corners of the doubler, and a cut-off wheel to finish the cuts to remove the center. I finished the inside edges. Once complete, I made two copies of the doubler (Murphy was an optimist :-) ). One from some 0.050 thick material to be used as a template for making the awl cut for the removable panel, and the second (from 0.040 thick material) was for Murphy's sake. I used a thicker piece for the guide based on previous experience. It was easy to slip off the edge when getting a little impatient because of the time it takes to make the awl cut. However, that method results in a very nice, tight fit for the panels.
18 Jan 2016 (3 hours, total time to date: 1993.0 hours)
I drilled out the 4 holes in the access panel cut-out template to 0.25 in. for the fly cutter. These holes are the center points for the inside corner radii. I cut the inside corners of the guide to a radius of 1.5 inches (the corner radius of the doubler is 0.75 inches). The access panel overlap is 0.75 inches to accommodate the #8 machine screws. Once the holes were cut in the template, I finished the inside cuts with a cut-off wheel. I finished the edges with a sanding drum and emery paper. Finally, I located the template on the tunnel, and started match drilling the #40 pilot holes through the tunnel. I will need to replace the template with the doubler to match drill the machine screw holes through the tunnel before making the awl cut. I simply started with the template because it is thicker and serves as a better drilling template.
19 Jan 2016 (1 hour, total time to date: 1994.0 hours)
I finished match drilling the pilot attachment holes through the access panel template. I then installed the doubler and match drilled the pilot holes for the access panel attachment. I also trimmed/finished the inside corners of the template. I found that the corners needed to be modified to provide more clearance for the #8 machine screw dimples.
20-21 Jan 2016 (2 hours, total time to date: 1996.0 hours)
I fabricated two stiffening angles from scrap 0.040 thick 2024-T3 sheet material. They will run across the front and back of the tunnel doubler to beef it up and create smaller shear cells in the tunnel. The front angle will go across the entire width of the tunnel to bridge the tunnel sides, but I can't do that at the back end since the area on each side of the radio stack must be clear for my feet. However, the radio stack supports on the tunnel are tied to the main BH through the rail guides. I will use shear clips to attach the back angle to the radio stack supports to provide the required support on each end. I replaced the radio stack support structure to locate the new angle & match drilled the angle attachment holes through the tunnel. I still need to trim the ends of the aft stiffening angle.
22 Jan 2016 (1 hour, total time to date: 1997.0 hours)
I used the steel clamp from my bending brake and a scrap piece of 1/2 in. thick pine to form a flange at the top of the forward stiffening angle. I used a hammer to form the flange, then cut/finished it to size. This will wrap over the exiting flange for the rudder pedal supports to eliminate sharp edges (will be helpful at some point when my arm is in the access hole working on the rudder pedals/brakes). It will also help prevent small objects from falling between the angles. I then positioned the angle & match drilled the attachment pilot holes through the angle. I removed the angle & trimmed/finished the edges before replacing it on the doubler. I have a little more trimming to do around two of the doubler attachment holes - these areas are marked in the photo.
23 Jan 2016 (3 hours, total time to date: 2000.0 hours)
I removed the forward doubler stiffening angle, used a 1/2 in. drum sander to trim the area around the nearest doubler rivet. I finished the edges, & replaced the angle. I then marked the inside edges of the aft stiffening angle for trimming, removed, trimmed, & finished the edges. I fabricated two shear clips to fit around the guide rails on the radio stack supports. I marked the fastener locations for the clips, removed the supports, & drilled the #40 pilot holes in the supports. I replaced the supports, clamped the clips in position, & match drilled the pilot holes through the shear clips. I still need to trim the shear clips on the stiffening angle legs, and drill the pilot attachment holes through the aft stiffening angle.
24 Jan 2016 (2 hours, total time to date: 2002.0 hours)
I removed the radio stack supports and trimmed the shear clips to shorten the angle leg that attaches to the aft tunnel doubler stiffener. I replaced the supports/shear clips, marked the interface between the angle and the shear clips, removed the angle, & drilled the attachment pilot holes through the angle. I will match drill these holes later once I have everything in place. Then, I trimmed the upper edge of the angle to remove material in the low stress areas and provide some clearance in case I ever need to run wire/coax under the radio stack. Finally, I returned to work on the throttle quadrant covers on the left center skin. I replaced the skin and the covers, & started drilling out the attachment holes to final size.