Midget Mustang Log (Jan 2016 +)

25-27 Jan 2016 (5 hours, total time to date: 2007.0 hours)

I finished drilling out the throttle quadrant cover attachment holes out to #29, removed the covers, de-burred the holes & dimpled them for #6 machine screws. I removed the cover support structure from the left skin and removed the skin so I can have better access to rivet the right skin to the air frame. I'm doing that side first because it will be easier to rivet the flap quadrant bracket to the right skin by reaching through the left side. Jasson came over on Tuesday evening to help me rivet the right skin and flap control quadrant. We riveted all of the 426 rivets (except 2 that are blocked by the fuselage jig vertical support) before calling it a night. I then resumed work on the support structure for the throttle control quadrant. I took the throttle quadrant apart, and de-burred the attachment holes in the front support plate.

28-30 Jan 2016 (6 hours, total time to date: 2013.0 hours)

I continued working on the parts for the throttle quadrant cover. I removed the protective plastic from all of the parts, finished de-burring all of the holes, dimpled the holes for the #6 machine screws, and dimpled the holes for the -4 rivets. I then drilled all of the #40 holes for the nut plates in all of the appropriate parts. I realized that I neglected to install a #10 nut plate in the elevator trim control quadrant, so I took that quadrant apart, drilled/finished the nut plate holes, and installed the nut plate. Then, I went over all of the parts and did the final finishing work prior to de-grease, etch, and alodine work. I included the shear clips for the aft tunnel angle stiffener.

31 Jan 2016 (3 hours, total time to date: 2016.0 hours)

I started work installing the nut plates on the throttle quadrant support structure. My friend, Rod, came over and we installed the two, right side skin rivets close to the rear spar carry through. I had to remove the upright jig supports first. Then, I replaced the right arm rest supports, and we drove the rivets along the bottom skin. I also replaced the arm rest cover to make sure everything fit correctly.

1 Feb 2016 (1 hour, total time to date: 2017.0 hours)

Continued work installing nut plates on the throttle quadrant support structure, and installed the 4 Cherry Max rivets in the shear clips at the trailing edge of the center seat supports.

2-3 Feb 2016 (3 hours, total time to date: 2020 hours)

I finished installing the nut plates in the throttle quadrant support structure. I also riveted the stiffening angles to the cover panels.

4-8 Feb 2016 (3 hours, total time to date: 2023.0 hours)

Not a lot going on because I'm waiting for riveting help. I decided to go ahead and install the 4 Cherry Max rivets behind the flap quadrant stand-off support. I used my hand squeezer and had some trouble getting the rivets to lock properly. I drilled two of the worst cases out, and reinstalled them. The second try worked, but it is very difficult to prevent the head of the squeezer from bouncing back and scratching the skin. I've been using duct tape to help protect the skin, but it's not the best solution. I decided to buy a pneumatic gun and will give that a try on the other two. When I drilled out the other 2, I ended up enlarging the holes slightly, so I ordered some over sized Cherry's. In the mean time, I fabricated a 0.040 in. thick doubler with a single wrap around flange to fit against the front side of the rudder pedal doubler. This will provide more support for the master cylinders. Finally, while waiting for parts, I reinstalled the vertical fin. I still need to fix the alignment issue with the upper rudder fitting.

9-12 Feb 2016 (3 hours, total time to date: 2026.0 hours)

Still waiting for some riveting help. I decided to buy a pneumatic rivet puller from Harbor Freight. What I didn't know was that it was not designed to work with the thinner Cherry Max stems. I spent a bit of time making modifications to the nose tip and clamps to get it to work. So far, I've had limited success, but will give it a little more time. Once I ground the clamps to grab the stem, the next problem was that the stems didn't go deeply enough in the clamps. The tool would simply spit the rivets out since the clamp would close behind the stem. I then ground off some of the material behind the reach of the stem, but the gripping area is marginal. Also, I worked on the upper rudder attach fitting. I laid out the attachment holes in a bracket to allow the upper fitting to line up vertically. Lots of checking and re-checking, but it worked out for the top, upper attachment bracket. Now, I still need to fabricate the bottom, upper bracket to match. The best way I can think of is to under-size the rudder attachment hole, get the fin spar attachment holes located, then match drill the attachment hole through the top. I'll make a spacer between the brackets to hold the drill in alignment.

13 Feb 2016 (2 hours, total time to date: 2028.0 hours)

Well, I managed to get my Harbor Freight rivet puller to work with the Cherry Max rivets. It's a single shot process because I have to remove the nose assembly after each rivet and remove the used stem by hand. All in all, not a bad deal considering the price of a Cherry Max pneumatic puller. Also, removing the nose assembly is very quick since I really don't need to get it more than hand tight anyway. It didn't completely solve the scratching problem since it also tends to hop when it pulls the rivet, but that was also easy to solve since the nose is flat (a little piece of duct tape does the trick nicely). I set a couple of practice rivets first, then replaced the two blind rivets that I had drilled out behind the flap quadrant stand-off with over sized rivets. Everything looks good, so now I'm ready for the next time I need to use those dreaded Cherry Max rivets :-).

I also did more thinking about the upper rudder bracket situation. It was too bad (for me) that MA made the error locating the upper rod end bearing on the rudder spar. Chris sent me 2 bracket blanks that had pilot holes drilled for the rod bearing, but no holes were drilled for the attachment to the fin spar. Now, that I have the top bracket located correctly, I need to get the bottom one properly located. I measured the rod end bearing for the proper spacing for the brackets. It was approximately 0.435-0.44. I cut a piece of 0.5 thick aluminum plate to just under 0.5 in. and used my disk sander to finish it to 0.436 (as flat and parallel as possible). I then drilled a #13 hole through this spacer. I'll see if I can finish this adventure tomorrow.

14 Feb 2016 (3 hours, total time to date: 2031.0 hours)

Since the original upper rudder attachment brackets are identical and symmetric (at least as far as I can tell), I decided to see if I could take advantage of that to create a drilling template for the attachment holes for my modified brackets. I had already made a steel template for replacement brackets when I thought I would have to make my own. I had already drilled the spar attachments with the proper hole spacing for each bracket (as well as the third hole for the rod end bearing). I bolted the new spacer between the original brackets with each base laying flat and parallel. I then checked to see if the assembly would fit on the rudder spar in the existing 4 attachment holes. This was really my lucky Valentines Day, because it fit like a glove. To be sure, I actually bolted the assembly in place and then tightened the bolt through the spacer so the original brackets would not move when I removed the assembly from the rudder spar. Then, I had a drilling pattern for all 4 holes. I bolted the upper holes to my bracket template, then match drilled the other two. Once I match drilled the first one, I installed an AN3 bolt in that hole to be sure that nothing would move when I drilled the 4th hole. Now, I had the drilling template I needed for the new brackets :-) The new top bracket had the correct left offset (~3/16 in.) - I managed to get that done correctly on 12 Feb. I bolted that bracket on one end of the new drilling template, drilled/reamed the blank bracket hole for the rod bearing to 0.188 in., bolted the blank bracket to the new bracket with the spacer (just like I had done with the original brackets) while clamping the base to the template. Then, I match drilled the remaining 2 attachment holes through the new, bottom bracket. Again, using a bolt after drilling the first hole to keep things steady. Once this was done, I ground down the left side of the new lower bracket to take care of the offset so it would fit inside the rudder spar. I finished the new brackets, de-greased them, and applied some gray engine enamel. I painted the new template as well and will keep it - just in case.

Finally, I started work cutting angle stock for the master brake cylinder attachment to the forward fuselage tunnel. I will be installing these on the 0.040 in. thick wrap around doubler I made earlier.

15-17 Feb 2016 (3 hours, total time to date: 2034.0 hours)

I temporarily replaced the new upper rudder mount brackets on the fin spar to check the fit. Looks very good. I then returned to work on the master brake cylinder brackets. I finished cutting the 1 x 1 x 0.062 angle stock for the brackets. I'm using 0.062 instead of 0.125 because I'll be using a double shear arrangement and will add a 0.062 doubler on each vertical leg to increase the bearing area. This also allows a more efficient transition from the tunnel floor, stiffener, and bracket. Again, this is my design and should not be interpreted as an official modification. I cut out the 0.062 doubler blanks and machined them to final shape. I also made 2 spares ;-). I drilled the #40 attachment pilot holes 0.625 in. from the base of the bracket, and transferred this hole to all 4 angles. I then drilled these holes out to 1/8 inch - no special reason for this, I will be drilling/reaming to 0.188 eventually. I just like to take things easy since you can't put the metal back.

18-21 Feb 2016 (4 hours, total time to date: 2038.0 hours)

Continued working on the master brake cylinder attachment situation. I did a little more finishing work on the brackets and laid out the fastener hole locations for the wrap around doubler. I drilled the center attachment pilot holes (away from the bracket locations) and match drilled them through the tunnel floor. I wanted to get the doubler mounted in place so that I could lay out the location of the brackets once the master cylinders were attached to the pedals. I decided to use -4 bolts through the pedals and upper cylinder fitting. The aluminum rods that came from MA may bend over time, and I need to use some spacers to hole the fittings in place. I don't want to have the aluminum inside a steel spacer anyway. I had already drilled out the holes in the pedals to 0.25, so it made sense to me. That meant that I had to drill/ream the upper cylinder fittings to 0.25 in. I purchased Grove cylinders with 0.5 inch upper eye bolt fittings, so I had enough material. I drilled out the upper fitting on one of my cylinders on my drill press in 1/64 steps and made the final ream to 0.2495. I hung the cylinder on the left pedal to check out the fit. I'll do the other later. Finally, I was able to get some help to finish the riveting work on the right center skin. Brian Smyers came over to help. We got all of the rivets except the upper one behind the main spar angle bracket. I'll have to use a Cherry Max there.

22-26 Feb 2016 (5 hours, total time to date: 2043.0 hours)

I drilled out the upper fitting on the other brake cylinder and went back to work on the lower cylinder attachment fittings. I drilled/reamed the cylinder attachment holes out to 0.162 so that I could use #8 machine screws to test fit the assembly on the tunnel to be sure that I had proper clearances and to see where the upper fitting would sit on the rudder pedal. I was a little concerned about getting the right amount of rudder pedal travel, so I rechecked it again. The plans call for 22.5 degrees of rudder travel each way with a control horn arm of 1.25 in. that means that the cable must move: 1.25 sin(22.5) = 0.478 in. each way from neutral. The cable attachment at the rudder pedal has an arm of 1.5 in., so the rudder pedals move 18.6 degrees each way. The pedal attach bolt as an arm of 6 in., so it moves just over 1.91 in. (let's call it 2) each way. It worked out so that the rudder pedal tube was a little close to my cylinder reservoirs when either pedal was at the forward limit, but I have about 0.1 in. to spare. I can make more adjustments when I rig the cables. It will be nice to be able to access the cylinders through the tunnel access panel and avoid running more tubing through the firewall. OK, enough on that. I drilled 2, #40 pilot attachment holes in each lower cylinder bracket and fabricated a spacer to bolt between each pair of brackets (with the respective doublers) to provide clearance for the lower cylinder attach lug. I bolted one assembly together and re-checked the clearance. I already established where the edge of each bracket would fit on the tunnel doubler, so I removed the doubler, clamped the assembly in place (I did the left one first), and match drilled the attachment holes through the doubler. I repeated this on the right side, replaced the doubler/bracket assemblies on the tunnel, and temporarily replaced the cylinders for the picture. I'll trim the base legs of the brackets later.

27 Feb 2016 (3 hours, total time to date: 2046.0 hours)

I got a lot done today. Installed the last Cherry Max rivet on the right center skin (behind the main spar brace), and installed the AN-3 bolts through the rear spar and the right lap belt supports. Brian Smyers came over to help me start riveting the left center skin to the air frame. We nearly finished it - other than the universal heads at the front and rear and the 2 blocked by the rear spar upright support. Then, I drilled the rivet holes through the master brake cylinder attachment brackets. These hold the upright doublers on the angle bracket.

28 Feb - 1 Mar 2016 (4 hours, total time to date: 2050.0 hours)

I C/S the rivet holes in the brake cylinder tunnel bracket doublers, prepared the surfaces for epoxy (scuff & de-greasing), applied T-88 epoxy to each surface, and riveted each assembly. Once cured, I used scotch brite to remove the excess epoxy and re-finished the parts. Finally, I drilled out the epoxy in the attachment hole and reamed the holes to 0.188 for the An-3 bolts.

2 Mar 2016 (1 hour, total time to date: 2051.0 hours)

Removed the rudder pedal assembly from the tunnel and removed the tunnel from the air frame. I used the spacer made earlier for each master brake cylinder attachment bracket assembly and replaced them on the doubler/tunnel (mostly to help hold the assembly in place), and match drilled the attachment holes through the doubler/tunnel to 1/8 in. Now, it will be easier to finish the tunnel and get it ready for final installation on the air frame.

4 Mar 2016 (2 hours, total time to date: 2053.0 hours)

Brian Smyers came over again after work to help me drive the remaining rivets holding the left center skin to the air frame. I had to remove the vertical support at the left rear spar attach point after we installed the 2, universal head rivets at the aft end of the center skin splice doubler to reach the 2 flush rivets below the rear spar. Once we were finished with the forward universal head rivets, I installed the single Cherry Max rivet behind the top of the main spar angle bracket. Finally, I replaced the vertical support, again, because Murphy was an optimist :-) .

5 Mar 2016 (3 hours, total time to date: 2056.0 hours)

I replaced the left arm rest support and Rod came over to help me drive the rivets through the bottom skin. We also riveted the lower throttle quadrant support and ignition support brackets to the inside of the left side skin. I then installed new AN3 bolts and stop nuts for the seat belt brackets through the rear spar carry through. Finally, I replaced the seat bottom with a few C/S #8 screws so that I can sit inside the airplane to work on the throttle quadrant structure.

6 Mar 2016 (4 hours, total time to date: 2060.0 hours)

Before I finish riveting the throttle quadrant cover brackets to the inside of the left skin, I needed to drill the holes for the headset, mic, and music input connectors on the aft bracket. I also checked for clearance between the elevator trim bell crank, the control cable, and the wiring coming off of the aft support. I decided to hang wiring stand-offs on the aft side of the trim control and the support bracket foe the forward end of my left arm rest support. I fabricated these brackets, finished/alodined them, and riveted them in place. Finally, I returned to the tunnel work and cut out the access panel using the trusty awl method. It's very slow (also, easy to slip and scratch), but you end up with a nice, tight fit with no material waste.

Hole Cutting Tool

Definitely a slow process, but I do like the results.

7-8 Mar 2016 (2 hours, total time to date: 2062.0 hours)

I finished the edges of the access panel cut out & drilled the doubler attach holes to 1/8 in. for dimpling. I also drilled/reamed the access panel attach holes to 0.162 inches for #8 C/S machine screws. Finally, I started de-burring/finishing the tunnel components (access panel, doublers).

9-10 Mar 2016 (2 hours, total time to date: 2064.0 hours)

I removed all of the protective plastic and completed all of the de-burring/finishing work for the tunnel components. the parts are now ready to be dimpled.

11-12 Mar 2016 (5 hours, total time to date: 2069.0 hours)

I had 2 shims clecoed at the front of the tunnel to fill the gap under the flange of the tunnel floor. I decided to epoxy them in place and install AD470 rivets to hold them in place while the epoxy cured (I'll remove those rivets later). I then went to work dimpling all of the parts. I used my C-frame to get to the holes in the tunnel that can't be reached with my squeezer. Then, I drilled all of the #8 nut plate attachment holes in the access panel doubler. Finally, I de-greased, etched, and alodined all of the parts that will attach to the tunnel.

13 Mar 2016 (2 hours, total time to date: 2071.0 hours)

I applied a light coat of primer on the surfaces of the alodined parts that will interface with the tunnel, and started installing the nut plates on the access panel doubler.

14 Mar 2016 (2 hours, total time to date: 2073.0 hours)

Jasson came over to help me finish riveting the throttle quadrant support structure to the left side skin. I also started riveting the doublers and radio stack supports to the tunnel, and Jasson helped me set some rivets that I can't reach with the squeezer.

15-16 Mar 2016 (4 hours, total time to date: 2077.0 hours)

I installed the top cover pieces of the throttle/elevator trim quadrants, and riveted them in place on the mounting angles using Cherry Max blind rivets. I had originally planned to rivet them to the angles before riveting them to the side skin, but was so happy to get the help riveting the angles to the skin, that I got a bit ahead of myself. Either way really doesn't make any difference (other than standard AD426 rivets would have looked better). The only good thing I can say about it is that it would have been more difficult to buck the rivets through the side skin if I had to work around the top with the flange behind the rivets, so all is well. I installed the rest of the rivets attaching the access panel doubler and stiffening angles to the tunnel. This took a good amount of time since I was doing it by myself. I clamped a 2x4 to my work table and clamped the tunnel vertically. This made it much easier to manage the rivet squeezer. I had to set the corner rivets with my rivet gun, but most of the rivets were done with the squeezer. I had one "oops" moment and had to drill a rivet out. I'm not too happy with the second one, so I will look into bucking a longer rivet inside a scrap piece of thicker aluminum (with a #28 hole to keep it as straight as possible) to enlarge the diameter before installing it back in the tunnel. If I can make this work, I'll get a much better fill in the hole and won't destroy the appearance of the tunnel. More on this tomorrow...

17 Mar 2016 (2 hours, total time to date: 2079.0 hours)

I cut a 1 x 2 piece of 0.25 in thick aluminum and drilled a #30 hole through it on my drill press. I C/S one side and made 2, 0.032 thick shims with #30 dimpled holes to nest in the thicker aluminum. I then drilled a 9/64 (instead of the #28) hole through the stack. I needed an expanded rivet that was 5/16 long. I inserted a AD426-4-6 rivet in the stack and set the stack on a bucking bar. I turned the pressure down to about 35 psi on my rivet gun and hit the head squarely. I then removed one shim and repeated the process. It worked even better than I thought. The new diameter was approx. 0.14 and the length was 0.315, I removed the bad rivet, cleaned up the hole, and installed my expanded rivet. It worked like a charm! The hole was filled nicely and the rivet set well. Then, I returned to work installing the doubler in front of the rudder pedals where the master brake cylinder mounting brackets will be installed. I installed all of the C/S rivets in this doubler.

18 Mar 2016 (1 hour, total time to date: 2080 hours)

I finished installing all of the rivets through the forward tunnel doubler and installed the master brake cylinder attachment brackets on each side of this doubler. All of the structure is now attached to the tunnel and I can temporarily replace it on the air frame and finish fitting the rudder cables and return springs.

19 Mar 2016 (2 hours, total time to date: 2082.0 hours)

I drilled out the holding rivets for the shims that I epoxied on the forward tunnel sides & replaced the tunnel on the air frame. I also replaced the radio stack the match drilled the attachment holes through the aft access panel doubler and shear clips attached to the radio stack rails out to 1/8 in (I'll ream these out to #30 immediately before final installation). I then replaced the rudder pedals so that I can start fitting the rudder cables and return springs.

24 Mar 2016 (1 hour, total time to date: 2083.0 hours)

I removed the seat bottom and ran the rudder cables through the fuselage to begin fitting the cables. I spent some time checking the fit for the return springs. This will take a little more Engineering effort. :-)

26 Mar 2016 (1 hour, total time to date: 2084.0 hours)

I really want to use compression springs for the rudder return system since they will last so much longer. I bought a set from Aircraft Spruce, but they will not work for the Midget. Those springs are too short (don't allow enough deflection for the full travel), and are too strong (~100 lbs/0.62 in.). I'd like to have about 40-50 lb/in and have an inch of total travel at the cable attach point. That would amount to approx. 10-12.5 lbs at the pedals at full deflection. Not much is really needed, but this will allow me to make some adjustments to the cable turnbuckles to add a little trim. I also need to work out the attachment at the firewall. It's very tempting to simply attach with eye bolts through the lower gussets, and I may end up going that way.

Anyhow, I replaced the rudder on the vertical fin and tested the cable control. My pulley system seems to be working very well.

27 Mar 2016 (2 hours, total time to date: 2086.0 hours)

I finally checked my fuel tank for leaks and found a few around the main seam and at 2 of the filler welds on the bottom of the tank. I marked the leaks with a grease pencil and dried out the tank. I'll have to give the guys at Phillips Sheet Metal a call and see if they can give me a hand fixing it.

28 Mar 2016 (2 hours, total time to date: 2088.0 hours)

I took the throttle quadrant apart in order to install the cover attach plate and replaced the assembly on the left side skin. I then installed the control arm between the center control and the elevator trim bell crank. Finally, I replaced the throttle/armrest covers and the instrument panel above the radio stack. I simply installed a few temporary fasteners to make sure that everything fits properly.

29-30 Mar 2016 (2 hours, total time to date: 2090.0 hours)

I got my fuel tank back from the shop (faster than expected), brought it back home and cleaned off all of the grease pencil markings for the leaks. I re-tested it and found 5 locations that were still leaking - although the situation was improved ;-). I also cut/finished some 0.05 in. thick steel tabs to weld to my compression spring fittings. This will allow me to attach each end between the firewall eye bolt and the rudder cable attach lug on the rudder pedals. Another friend at work welded them for me. I also ordered some new compression springs with a lower spring constant (~50 lbs/in) that I think will work much better for the Midget.

2 Apr 2016 (2 hours, total time to date: 2092.0 hours)

I received my new compression springs, so I drilled the attachment holes in two of the tabs welded to the spring fittings. I also drilled the eye bolt attachment hole through the lower firewall gusset and installed the eye bolts. I assembled one of the compression springs and test fit it to the rudder cable control. I wanted to double check the location for the attachment hole in the second compression spring attachment tab. I then removed the spring, disassembled the parts and drilled the attachment hole in the other tab for both springs. I re-assembled the springs and replaced them on the air frame to check the fit. I may end up going with yet another spring, but this is a good place to start.

4-5 Apr 2016 (2 hours, total time to date: 2094.0 hours)

I started work building the fuel tank support structure. I cut 1.5 x 1.5 x 0.125 2024-T3 angles for the back of the tank. I also cut a splice plate to attach the angles to match the shape of the tank bottom. I can use a 0.090 thick splice plate since it has a larger surface area. I laid out the fastener pattern on the splice plate, aligned the angles with the splice plate, and match drilled the attachment holes in the angles. I used larger angles than called for because I want to run 1 x 1 x 0.0625 supports (4) under the tank, and I also want to have a little extra material to allow more room for supports to run diagonally from the upper stringers. The tank support is really like a porch swing, and the only longitudinal support comes from friction at the top of the tank. IMO, this is not sufficient in case of a crash. I will also be clamping my tank down from the top, instead of pulling it up. Once I know exactly how everything will fit, I hope to be able to trim some of the unnecessary material.

6-7 Apr 2016 (2 hours, total time to date: 2096.0 hours)

I fabricated the forward tank support following the same procedure used for the aft support. The front support is somewhat smaller due to the shape of the tank. I also fabricated 0.062 thick angles to fit along the C/L of the supports. I will install a 0.040 thick strap across the bottom edge.

Apr 9-10 2016 (6 hours, total time to date: 2102.0 hours)

I got quite a bit done over the weekend. I drilled out the attachment holes in the fuel tank supports to #21 (I decided to use -5 rivets to take advantage of the higher tension capability - to provide extra support for crash worthiness). I de-burred the holes, finished the edges, and de-glossed/de-greased the parts. I decided to use some tank sealant to the assembly. I had some that had recently expired and it is a very good way to prevent condensation between the layers. I then riveted the parts. After that I went to work on the rudder cables. I clamped the rudder in the neutral position and installed the turnbuckles/thimbles/sleeves in each side. I adjusted the turnbuckles so that I had just covered the threads in the barrel with the cables tight and neutral. That gives me plenty of room for future adjustment and ensures full thread capture.

16 Apr 2016 (5 hours, total time to date: 2107.0 hours)

I went back to work on the fuel tank support structure. I cut 4, 1 x 1 x 0.062 angles as stiffeners across the fore and aft tank supports. The center supports are spaced 2.75 in. apart along the lower tank bend lines. My tank differs from the plans because my fuel line bung is approx. 2 inches in diameter, and my bending brake anvil is 2.75 in. wide. I used 2, 1.5 x 0.25 trim boards to hold the fore/aft supports to the proper spacing for the tank, and measured the required length of the angle stiffeners to fit inside the supports. I cut one side of the angles on each end, finished them to be flush to fit, and finished the edges of these stiffeners. I located them on the support structure, laid out the fastener holes, and drilled #40 pilot attachment holes in each end of the stiffeners. I replaced the stiffeners on the structure, and match drilled the pilot holes through the fore/aft tank supports. I used -3 rivets to hold the stiffeners in place and placed the tank in the support to determine the location for the side stiffeners. I clamped the trim boards along the bottom outside edges of the tank and used them as guides for the side stiffeners. I repeated the process of cutting/finishing the stiffening angles to fabricate the side supports and clecoed the assembly together.

17-18 Apr 2016 (3 hours, total time to date: 2110 hours)

I was finally ready to pressure test the fuel tank. I used plastic tubing as a manometer to monitor the tank pressure and attached a quick connect fitting to a hose with a 1/4 pipe thread on the other end and connected it to my fuel outlet valve. I connected the manometer tube to one of the 1/8 fittings on the top of the tank, plugged the other openings and ran the pressure up in steps to just under 1.5 psi (~40 inches of water). I brushed some soapy water on all of the joints and found 3 small leaks. Also, the tank pillowed quite a bit and was really "talking" to me. I'm not happy with the look of the flanges. The local bending is evident. I took the tank back to the welder and he went back over the areas again. I also talked to him about the situation with the flanges. After discussing it with him, I will go ahead and make a new tank from heavier gauge 5052 (I'll see how 0.05 looks) with overlapping joints around the circumference and no flanges on the end caps. I know the 0.032 is strong enough by itself, but I think the welds will be better with thicker material, and it should eliminate the warping around the thick filler cap fitting. The last thing I want is to be constantly worrying about the tank when I'm flying. Once I get it re-done, I'll test the old tank to failure - just to observe the failure mechanism and satisfy my curiosity. The good thing about it is that I was able to use it to check the space available in the forward fuselage and get the other structure installed.

I also cut/bent/finished two 0.040 2024-T3 straps to attach under the fore/aft tank support angles to connect the cut sections. I drilled #40 pilot holes through the parts.

20 Apr 2016 (1 hour, total time to date: 2111 hours)

I laid out the attachment hole locations on the bottom flange of both fuel tank supports that will be used for the 1/8 in. thick plywood that I plan to install between the longitudinal stiffeners. I will then overlay them with another layer of 1/8 in. plywood laminated with T-88 epoxy. I'll have to cut some strips of 1/16 plywood to fit over the top of the longitudinal stiffeners. I drilled those pilot holes to #40 and will match drill through the plywood later. I also drilled out the attachment holes for the longitudinal stiffeners and straps to 1/8 in.

23 Apr 2016 (3 hours, total time to date: 2114.0 hours)

I fabricated 4 angles from some scrap 0.032 aluminum to cover the rivet tails along the lower edge of the fore and aft tank support angles. The idea is to prevent the edgers of the rivets from rubbing against the fuel tank and provide a flat surface for the rubber sheet to protect the tank. Otherwise, I'm afraid the tails will wear through the rubber sheet. Once finished, I used duct tape and a clamp to hold each angle in place & match drilled the attachment holes through the tank supports. I also duplicated the elevator trim tab control horn - just in case anything happens to it. It will be much more difficult to replace it later. Finally, I removed the eye bolts through the firewall. I need to re-install them with some RTV to make sure I have a good seal.

24 Apr 2016 (1 hour, total time to date: 2115.0 hours)

Didn't get much done today, but I cut some 1/8 inch plywood to use on the fuel tank support. I decided to use 1/16 plywood between the longitudinal supports and laminate the 1/8 on top of it. That way, I won't have to fill on top of the supports. So the means I'll have to wait until I can get some 1/16 plywood. Also, I replaced the rudder return spring eye bolts with some RTV to seal the holes.

25 Apr 2016 (2 hours, total time to date: 2117.0 hours)

I fabricated 0.032 shims to fit over the angles covering the fuel tank support rivet tails. These shims will level the lower edge to the top of the 0.062 longitudinal supports so that the final 1/8 inch plywood layer will sit flush. The 1/16 plywood will lay inside all of this structure and form a level layer to laminate the thicker plywood. I drilled/reamed out the attachment holes through the shims, lower fuel tank support straps and longitudinal supports to #30. I then C/S the holes through the shims. Finally, I took everything apart and de-burred the parts.

26 Apr 2016 (2 hours, total time to date: 2119.0 hours)

I C/S the attachment holes in the longitudinal supports, went over the surfaces with Scotch Brite, and wiped them down with acetone. I then used my PPG de-greaser to remove any residue, etched, and alodined the parts. I decided to do the same to the main tank supports in preparation for assembly.

27 Apr 2016 (2 hours, total time to date: 2121.0 hours)

I riveted the tank support structure with the exception of the angles that cover the rivet tails on each side of the support.

28 Apr 2016 (1 hour, total time to date: 2122.0 hours)

Replaced one of the rivets on one of the longitudinal supports and finished riveting the support frame.

30 Apr 2016 (3 hours, total time to date: 2125.0 hours)

Before making the new tank, I decided to look at the option of mounting the tank directly to the upper stringers. I saw a used MM1 fuel tank on-line that had welded 0.062 angles on each side to sit on the stringers. One of the challenges is the fact that the stringer is twisted to match the upper side skin curvature. Also, if mounted without the cradle (I know, all that work down the drain), the tank becomes part of the air frame and must be completely self supporting. I took several measurements of the upper stringers and designed a new tank to be very similar in overall shape, but with more attention to the fit/taper between the stringers. I laid it out on paper, and cut out the lower tank pattern blank from a sheet of 0.050 in. thick 5052-H32 aluminum.

I'll save everything I have - just in case I need to go back to the original plan.

1 May 2016 (1 hour, total time to date: 2126.0 hours)

I received the new tank material and started work on the lower portion of the tank. I used my original template to trace the area to cut out of the sheet, and made cut out the pattern using a cut-off wheel.

2 May 2016 (1 hour, total time to date: 2127.0 hours)

I checked my measurements and calculated the proper dimensions for the bend lines on the lower tank. I also double checked the dimensions for the edges to allow for the forward cant along the aft end to match the 6 degree slope of the instrument panel. I want the tank to be as large as possible, but retain at least 6 inches in front of the IP. I believe I will end up with approximately 6.375 inches. I laid out the bend and cutting lines for the template.

5 May 2016 (1 hour, total time to date: 2128.0 hours)

I laid out the pattern for 3/4 in. wide beads to stiffen the tank walls between the baffle and each end. I drilled the fuel supply bung hole on the C/L of the tank bottom. Then, I took the tank pattern over to the sheet metal shop. They have a bead roller and bending press. I left it for them to work it in when they can.

7 May 2016 (4 hours, total time to date: 2132.0 hours)

While waiting for the new tank to be beaded/bent, I decided to install the antenna doubler on the tunnel floor. Now is a good time to get it done (before it's permanently installed). I removed the tunnel structure from the air frame & laid out the position of the doubler on the floor. I made a duplicate doubler from some scrap 0.040 material so I could use it as a drilling guide through the floor. I wanted to make the antenna easier to install, so I decided to use floating nut plates. I'm probably going to have to add some grounding wires to attach to the machine screws (if I don't get a good ground through the anodized nut plate). Also, I decided to rivet the doubler to the floor so that I could mount the nut plates directly to the doubler, then attach the doubler to the floor. I drilled the pilot attachment holes in the doubler, then replaced the doubler on the floor and match drilled these holes. I then drilled them out to 1/8 in the floor and #30 in the doubler. I dimpled the holes in the floor and C/S the holes in the doubler. I then laid out and drilled the nut plate attachment holes in the doubler and C/S them for NAS1097-3 rivets. I decided to apply a light coat of primer on the mating surfaces. The ground connection for the antenna goes through the #8 attachment machine screws, so this really won't matter for the ground. It will help slow down corrosion between the doubler and floor. I installed the nut plates, replaced the doubler on the tunnel, and riveted the doubler to the floor. I then checked the ground connection through the antenna attach screws. It wasn't the greatest, so I worked the floating nut plates around to see if it helped to make a better connection. It did, but I still think I'll drill a hole in the the rear stiffening flange of the access panel to allow me to add a grounding wire if I need it later. I hope not, but better to do it now instead of later when access will be much more limited.

8 May 2016 (1 hour, total time to date: 2133.0 hours)

I riveted the remaining holes in the radio stack support structure that is connected to the tunnel. I also drilled/reamed a hole for a #8 machine screw in the rear access panel stiffening flange for a ground wire in case I need it for the antenna connection.

9 May 2016 (1 hour, total time to date: 2134.0 hours)

Installed a #8 nut plate for the antenna ground wire attachment to the air frame. This makes it much easier to attach the wire(s) if needed. I then replaced the tunnel on the structure.

Also, it turned out that the cowling I found on Barnstormers did not fit on my firewall. Evidently, there is a MMI modification out there with a wider/taller firewall. Bummer. Now it looks more likely that I'll have to make my own.

10-14 May 2016 (3 hours, total time to date: 2137.0 hours)

Still waiting to hear back from the sheet metal shop about any progress beading and bending the new fuel tank bottom. In the mean time, I went back to work on the elevator control system. I re-checked the fit of the push/pull rod between the control stick and bell crank. It looked right, so I took the tube and rod ends to another friend to weld. I then prepped/applied enamel primer to the tube and let it dry overnight. I installed it in the airplane. Then, I did the same with the aluminum tube from the bell crank to the pass-thru at BH182. Although, I didn't prime it. I will need to fabricate some nylon spacers on the 1/4 in. pivot bolt in the bell crack housing to hold the bell crank in position (laterally).

16 May 2016 (2 hours, total time to date: 2139.0 hours)

I removed the vertical fin/rudder so that I could replace the stabilizer/elevator. I need to check the fit for the elevator push rod and the trim cable. Since the rudder cable ends don't clear the fin spar pass-through holes, I'll be juggling these parts for a little while. I also had to trim/finish the stabilizer skin a bit since I added the angle stiffeners to the tail cone to flatten it between the aft BHs. I also had forgotten how much time it takes to install the elevator. I made the cut-outs as small as I could, and the bolts only install from the bottom.

17-18 May 2016 (3 hours, total time to date: 2142.0 hours)

I marked the elevator skins so that I can trim the inside corners to provide clearance for the tail cone fairing and checked out the situation for the trim cable and push rod attachment to the bell crank. I then removed the rudder and made a drilling guide for the bell crank attachment hole. I drilled a #40 pilot hole on one side, then cut out a piece of 0.5 inch aluminum stock and machined it down to 0.435 thickness, drilled a straight #40 hole through it on my drill press and clamped it inside the bell crank (matching up the hole on one side). This served as a guide to ensure that the attachment hole was straight and true across the bell crank attachment. Once I had the pilot hole through both sides, I progressively drilled each side out to #13 and used an existing guide I had made for the rudder attachment fitting to ream the hole through to 0.188 in. for the attachment bolt. I trimmed/finished the corners of the elevator skins. Finally, I laid out the location for the trim cable pass through at BH177.5. The plans call for drilling a 0.25 in. hole on the stabilizer C/L, 0.75 inches from the left side of the BH flange. Based on the drawings, this would be approximately 0.2 in. to the right of the line drawn alone the vertical C/L of the two bolts on the left side of the BH. I made another drilling guide, duct taped it in position, and drilled a #30 pilot hole through the spar and BH. I progressively drilled this hole to size D, then reamed it out to 0.249. Finally, I routed the trim cable through this hole to check out the fit.

20-23 May 2016 (4 hours, total time to date: 2146.0 hours)

I cut two pieces of 4130 tubing for the elevator push rod extension through BH 177.5. One is 0.75 x 0.035 and the other is 0.5 x 0.058. I cut two because I don't have the rod end to fit the elevator end for the 0.5 tubing, and I wanted to check the fit as soon as possible. I'd rather use the 0.5 tubing since it has more clearance at the pass thru. The diameter is no issue since the extension is only 2-3 inches long. I asked my welder friend to weld rod ends on both that will fit the aluminum adapter (3/8 x 24). I cut the 0.75 tube to approximate length and installed it on the aluminum push rod. I then replaced the elevator to check it out. I lucked out and it was nearly the perfect length. There was some rubbing at the upper right corner of the pass through, and I noticed that I needed to trim the corners of the elevator skin a little more. I removed the elevator, took a little out of the pass through hole (just to have the extra clearance for the 0.5 tube), and trimmed/finished the elevator corners again. Now I know the proper length for the 0.5 diameter extension tube.

25-26 May 2016 (2 hours, total time to date: 2148.0 hours)

I cut the 0.5 in. extension tube to the correct length based and am waiting on the new rod end. I returned to work on the main fuel tank support angles. I cut 2 blanks for the side angles (to attach to the upper stringers) and 2 blanks for the bottom support out of 5052-H32 0.063 in. thick sheet material. the bottom angles will be 1x1 and the sides will start out as 1x1.5 and will be trimmed once I see how they fit on the stringers. These are more complicated since the stringers have some twist between BH52 and BH73.75. I cut the blanks to 16 in. long and bent them on a bigger brake at work. I was able to get more bend on one side of each side stiffener by releasing the anvil more on one end. It worked fairly well, but I'll need to make some adjustments once I get the tank skin back from the sheet metal shop.

27-28 May 2016 (2 hours, total time to date: 2150.0 hours)

I cut/finished the 0.5 in. dia. extension tube for the elevator control. I got my new fuel tank bottom back from the sheet metal shop. It turned out very well. I then laid out the stiffening angles on the upper stringers and cut them to the approximate final length. I also trimmed them around the rivet heads at the engine mount brackets.

29-30 May 2016 (4 hours, total time to date: 2154.0 hours)

I fabricated two, 3/4 in. thick plywood forms to hold the tank bottom in proper shape so that I can check the fit inside the airplane. I need to know where to attach the side angle stiffeners that will sit on the upper stringers. I then clamped the forms to the tank bottom and fit it in the tank - making adjustments to ensure proper clearance for the fuel line/shut-off valve.

2-4 Jun 2016 (3 hours, total time to date: 2158.0 hours)

I trimmed the ends of the fuel tank angle stiffeners to allow some space on each side for welding the end caps later. I checked the tank fit again, clamped the stiffeners in place and brought the parts to the sheet metal shop to ask the welder how much overlap he wants for the top of the tank. I also brought the elevator push rod extension with me to have the aft rod end welded to the extension. The welder thinks that 1 inch will allow him to easily weld the top of the tank over the side stiffeners. I cut the excess from the tank bottom, removed the protective plastic, and clamped the stiffeners back in place. I want to check everything one more time before taking the parts back for welding.

5-6 Jun 2016 (3 hours, total time to date: 2161.0 hours)

I spent a little more time working on the side stiffening angles. I cut them a little shorter to allow more space at each end for the end cap welds. I also trimmed the forward flange to allow more clearance with the engine mount rivet heads. This will also allow me to slide the tank forward a bit more. I finished the edges, rubbed them down with acetone to remove any grit, and replaced the tank bottom to re-check the fit. I clamped the side angles in place, and took the parts to the welder. He ran 5 welds along each side to minimize warping. I brought the tank home and cut some 3/4 plywood to fit in the stringer channel so I can clamp the bottom to the stringers and start working on the top of the tank.

7-11 Jun 2016 (6 hours, total time to date: 2167.0 hours)

My good friend and FAA/DER, Tom Dieters, took a look at the picture of the welded stiffeners and had a few questions for me about the weld. I decided to call another welding shop here in Dayton and brought it in to be inspected. The other welder told me that the TIG welds were generally OK, but there were some minor issues at the start/stop points (some over heating). Also, he said that the area should have been cleaned up a bit more before welding. I decided to have him do the rest of the welding. He told me that he will fix the issues with the current welds, and pressure test the finished tank. I just need to get all of the parts finished and bring it all over at one time.

I cut some scrap 1/4 inch plywood to 3, 20x20 pieces to make templates for the end caps and baffle. I cut the end caps to fit inside the lower portion of the tank (while it was clamped in the forward fuselage). I also used my router to cut a slot along the edge in a few locations so that I could clamp the templates in the tank. I let the upper portion long so that I could measure /trim the templates to allow needed clearance for the vent/fuel refill bungs as well as the filler neck. I decided not to try to round the top since the 0.050 material is more difficult to shape and it will be easier to fit the parts with straight edges. Once I had the measurements finished, I trimmed the tops of the end caps and checked them for level/symmetry.A few iterations, but it looks good now.

I made a cardboard template for the top of the tank based on the measurements of the end cap templates. I also trimmed the templates where the top overlaps the bottom skin on the inside. The picture below was taken before I tucked the top template inside the bottom skin.

12-13 Jun 2016 (4 hours, total time to date: 2171.0 hours)

I cut the material for the top of the tank and marked it for bending. I also cut out the blanks for the end caps and laid out the bead lines on each end cap. I took the end caps over to the sheet metal shop, and Rob allowed me to use his bead roller on the end cap blanks. I then bent the tank top and brought it home to check the fit. I made a goof on one of the bend lines, so I cut out another blank and marked it for bending. Hopefully, the second try will be better. :-)

14-15 Jun 2016 (3 hours, total time to date: 2174.0 hours)

Wow, bending that top was more of a challenge than expected. The second attempt was better as far as hitting the bend lines, but my measurements were off due to the differences between the cardboard template and the 0.050 aluminum. So, I made another blank (adjusting for the difference), and tried it again. Third time seems to be a charm. I set up a temporary stand to check the fit. I have some trimming to do, but otherwise, it looks good.

16-19 Jun 2016 (7 hours, total time to date: 2181.0 hours)

I tried everything I could think of to avoid drilling any holes to temporarily connect the upper and lower portions of the tank, but in the end, I decided to go ahead and drill 3, #40 holes on each side to hold the tank together. The clamps would simply slip off and would not hold tightly enough to fit the baffle. I aligned the tank, and drilled the attachment holes. I installed clecos to hold things together. I trimmed the ends and fabricated a plywood baffle template. I then, laid out the baffle on a piece of 0.050 aluminum (5052-H32). I cut out the blank, and cut the corner holes. I took the blank over to a shop with a bigger bending brake, and bent the flanges. I brought it home and checked the fit. Everything looked good, so I cut the internal baffle holes and trimmed the flanges. Finally, I replaced the baffle in the tank.

20 Jun 2016 (4 hours, total time to date: 2185.0 hours)

Finished my work on the tank, so it's ready for welding. I cut the bung holes on the top of the tank for the vent and fuel transfer. I then cut the hole for the fuel probe, and the 5 attachment holes. As I did for the first tank, I riveted the fuel probe flange inside the top of the tank. Before riveting, I sprayed a light coat of engine enamel on the steel flange. This just makes it much easier than trying to fish the flange in the tank after it's finished. I used the cover I made for tank 1.0 and bolted it on the top. Then, I cut the filler neck hole in the top as well as fabricating a 0.050 doubler to sit under the filler neck. This does 2 things for me. First, it reinforces the area around the filler neck. It also raises it slightly so that the cap will sit essentially level with the top skin. I finished the edges of the holes in the top. Finally, I trimmed/finished the end caps to fit.

24 Jun 2016

I dropped off the new fuel tank for welding and will be out of town for a week. The tank should be ready for me to pick up by 5 July. I have other work that can be done when I return, so this will work out fine.

5 Jul 2016 (1 hour, total time to date: 2186.0 hours)

I picked up the new fuel tank from the welder today. I'm so glad it's finally finished! I also removed the steel brackets that I had tack riveted to the stringers when I thought I'd be using that "porch swing" method to mount the fuel tank.

11 Jul 2016

I received and installed a trim seal to prevent contact between the tank and the upper firewall stiffener.

13-14 Jul 2016 (2 hours, total time to date: 2188.0 hours)

I removed the old doublers along the upper fuselage stringers, and used them as templates for new doublers. The old doublers were cut to fit the steel brackets that are used in the plans to support the "porch swing" for the fuel tank. Since I'm not using that method, I needed to make new doublers. I replaced the new doublers and match drilled the holes that had been enlarged to 1/8 inch. I left the rest at #40 and will drill them out later.

17 Jul 2016 (5 hours, total time to date: 2193.0 hours)

I temporarily removed the upper stringer doublers and fabricated four, smaller "wrap-around" doublers to attach to the upper stringers to help support the fuel tank. These doublers will strengthen the attachment points and provide twice the bearing capability of the attachment holes for the fuel tank attachment flange. I fabricated four of these doublers for each corner of the tank flange, measured/marked the attachment hole locations, and drilled #40 pilot attachment holes through the tank flange. Because of the angle of the flange, I used an angle drill for these holes. I damaged one of the holes on the aft, right side. I drilled out the majority of the damage, but will need to fabricate a doubler for the flange - just to be safe. The loads are not high, but I don't want to use it as is. Also, it will be better to install small doublers along the flange attachment holes using 2024-T3. This will provide more bearing area and resist wear over time.

18 Jul 2016 (2 hours, total time to date: 2195.0 hours)

I fabricated the remaining two wrap-around doublers for the fuel tank flange attachment that fit slightly aft of the mid-point of the fuel tank flange. I used a drilling guide and a long #40 drill bit this time to avoid my previous foul up. I then removed the tank, clecoed the doublers back on the stringers, and match drilled the attachment holes through the outside of the upper stringers. I cleaned up the holes and replaced the tank.

19 Jul 2016 (2 hours, total time to date: 2197.0 hours)

I laid out the left stringer doubler (0.040 in. thick) and marked the edges of the 0.040 in. thick tank support angle doublers. I trimmed/finished the doubler to fit around these angles. This took some time to get a decent fit with a moderate amount of clearance. After finishing this, it seemed to me that I would have been better off making this as one piece. I originally didn't do this because of the twist in the stringers and I thought I'd get a better fit with 3, separate angle brackets. However, I have already made these doublers to allow room for rivets on each side of the tank attachment holes. So, I may as well re-make the doubler and rivet it along the top edge of the stringers. This is more lost time, but will result in a more robust structure with minimal weight penalty. As it is, I've already eliminated the "porch swing" tank support. I've added the stringer doublers and two more AN3 bolts, but these weigh much less than the porch swing structure. The tank is also thicker (0.050 vs. 0.032), but all of this works out as less total weight, and is a much better design IMO.

23 Jul 2016 (2 hours, total time to date: 2199.0 hours)

I didn't have a piece of 0.040 2024-T3 large enough to re-do the new angle doublers for the fuel tank attachment to the stringers. I ordered more, and just got the material. I cut out the blanks for each side, and started work on the left doubler. I laid out the pattern for the upper leg and trimmed it before making the bend. I also drilled 1/4 inch holes at the bend corners for stress relief. I bent the angle, and started work finishing some of the edges.

24 Jul 2016 (3 hours, total time to date: 2202.0 hours)

I replaced the new left angle doubler on the upper stringer and did a little trimming/finishing on each end to fit between the BHs. I then match drilled several of the #40 holes along the stringer, removed the doubler, clecoed the old doubler through these holes, and match drilled the rest of the holes through the new doubler. I wanted to do as little damage to the stringer as possible, and the old doubler allowed me to locate the attachment holes accurately. I replaced the new doubler, checked the tank fit, and made a few more adjustments to the top leg of the angle to allow a nice fit for the tank. Once I had that finished, I replaced the tank again and match drilled the three attachment holes through the tank attach flange. Then, I repeated the process on the right side. I stopped at the point where it was time to drill through the right tank attach flange. Since I already have the 3/16 hole reamed at the aft end, I need to be very careful how I drill this one. I'll do that tomorrow. :-)

25 Jul 2016 (1 hour, total time to date: 2203.0 hours)

I used a duplicating punch through the tank flange to find the center of the existing 0.188 hole in the right stringer. I removed the tank and the new right double, and drilled a #40 pilot hole through the punch mark in the doubler. I then progressively drilled out this hole to #13, replaced the parts, and match-reamed this hole through the tank flange. I inserted an AN3 bolt in this hole, and match drilled the other two #40 holes through the tank flange.

26 Jul 2016 (1 hour, total time to date: 2204.0 hours)

I marked the overhang of the tank attachment flanges for trimming along the outside of the stringer doublers, removed the tank, and trimmed/finished each flange. I then replaced the tank on the air frame.

1 Aug 2016 (1 hour, total time to date: 2205.0 hours)

Back to work on the Midget. I noticed that the tank attach flange on the right side was slightly proud relative to the stringer doubler, so I removed the tank, took a little more off of the flange, and re-finished the edge. I then pulled out the forward side skins, removed the plastic around the lower attachment holes (along the tunnel flange), de-burred the holes and free edges, and dimpled the 14 attachment holes on each skin.

2 Aug 2016 (1 hour, total time to date: 2206.0 hours)

I drilled out all of the NAS 1097-3 holding rivets on the cowling attach strip/firewall flange. These needed to be removed so that I could match drill all of the holes through the forward side skins to final size.

3 Aug 2016 (1 hour, total time to date: 2207.0 hours)

I had forgotten that I also needed to dimple the attachment holes in the forward skins along the doubler attached to the flange of BH73.75. I removed the plastic around these holes, de-burred the holes, and dimpled them. I then replaced the left skin on the air frame and removed the fuel tank to get better access to the inside. I started work match drilling the attachment holes through the upper and lower stringers/doublers to final size.

4 Aug 2016 (1 hour, total time to date: 2208.0 hours)

I drilled/reamed the #8 nut plate attachment holes out to 0.162 in. along the upper left stringer doubler. This is a change from the plans. Mostly because I don't like the idea of #6 machine screws anywhere on the outside of the airplane. There just too easy to strip and are more exposed to the elements. It also keeps things easier along the stringer - instead of squeezing wo rows of fastener holes inside the c-channel. I then drilled out the firewall flange attachment holes on the left side. I had to remove the spacers at the engine mounts to gain access to the holes in these areas. I simply removed one at a time, drilled these holes out to 1/8 in., de-burred the SS flange holes, and replaced the bolts/spacers. I want to have everything drilled out and ready for finishing before I remove the left skin one last time. When I remove this skin, I'll be ready to do the same work on the right side.

5-7 Aug 2016 (6 hours, total time to date: 2214.0 hours)

I removed the upper, left doubler and laid out the fastener hole locations for rivets between the #8 machine screw holes. The spacing I've used between these holes is 2.5 inches, so adding rivets between these holes pull the skin tighter against the doubler and help keep water out of this area. I drilled #40 pilot holes in the doubler, replaced the doubler, and match drilled these holes through the left skin. I marked the left skin for trimming along the top and front edges and removed it for finishing. Then, I replaced the right front skin and drilled the attachment holes along the stringer doublers and firewall flange. Of course, I had to remove/replace the engine mount spacers to get to the holes in these areas. I also started work trimming/finishing the left forward skin.

8 Aug 2016 (1 hour, total time to date: 2215.0 hours)

I had a little more work to do on the right forward skin. I removed the upper stringer doubler, marked the fastener hole locations between each of the holes to attach the top skin, drilled #40 pilot holes, replaced the doubler, and match drilled out these holes to 1/8 inch. I had neglected to open the skin attachment hole at the firewall flange to 0.162 in. along the attachment line for the upper skin. I took care of this as well and de-burred this hole in the firewall flange.

9 Aug 2016 (1 hour, total time to date: 2216.0 hours)

I laid out the wing root tip rib over the left forward skin to see where I can run the brake line. I want to attach a BH fitting through the side doubler. It looks like I can, so I laid out the hole location as well as additional attachment holes between the skin and doubler, I'll use sealant between the layers here as well as all other areas in the front. I still haven't decided how I'll run the exhaust, so I want to seal the area well.

10 Aug 2016 (1 hour, total time to date: 2217.0 hours)

I drilled #40 pilot holes in the left skin to attach to the side doubler, replaced the skin, & match drilled these holes out to 1/8 inch. I then removed the left skin/doublers and finished de-burring these parts.

11 Aug 2016 (1 hour, total time to date: 2218.0 hours)

Since the right, forward skin was still attached to the air frame, I decided to drill the holes through the right side doubler itself (instead of removing the right skin and repeating what I did yesterday). I removed the radio stack, marked the hole locations on the right doubler, and drilled #40 pilot holes through a drill guide. I then drilled the holes out to 1/8 in. from the outside and clecoed them as I went.

The lower, forward hole through the doubler will be the pass-through for the brake line on each side.

12 Aug 2016 (2 hours, total time to date: 2220.0 hours)

I removed the right forward skin, trimmed the forward/top edges of the skin, and de-burred/finished the parts.

13 Aug 2016 (2 hours, total time to date: 2224.0 hours)

I dimpled the #8 machine screw holes in each side skin and upper doublers. Then I dimpled the 1/8 in. rivet holes in each of these lines, reassembled the parts, and set the dimples. I also dimpled the 1/8 inch rivet holes along the front and top of each side skin. Finally, I dimpled the 1/8 inch rivet holes near the upper end of the fuselage side doublers.

I'm waiting for some help riveting and installing machine screws to finally attach the tunnel structure. Hopefully, next weekend.

18 Aug 2016 (1 hour, total time to date: 2225.0 hours)

I dimpled all of the remaining attachment holes in both forward side skins. These holes are along the lower stringers where the skin is curved and more difficult to dimple. I used my rivet gun with the dimple set and one of my tungsten bucking bars with the other die inserted in a hole drilled in it. This has always worked very well.

19 Aug 2016 (1 hour, total time to date: 2226.0 hours)

I drilled out the attachment holes along the upper firewall flange and the top of the IP. I'm using #8 machine screws to attach the top skin and will be using every other fastener hole in these areas for these screws. The other holes will be dimpled for 1/8 inch rivets to attach the 0.032 strips to the flanges. I drilled all of the holes out to 1/8 in., then opened every other hole to #21 with a final ream to 0.162 in.

20 Aug 2016 (4 hours, total time to date: 2230.0 hours)

Jasson came over today and helped me seal, rivet, and screw the tunnel structure on the air frame. I cut about 3/16 off of the threads of the #8 structural machine screws so that they would not hit the bottom main spar flange and allow about 2-3 threads past the nuts. We removed the rudder pedals and radio stack to allow enough room to work. We removed the tunnel and applied the sealant along the rivet lines and the machine screw line at the main BH. We clecoed the tunnel in place and installed the button head -4 rivets along the lower firewall stiffener and lower sides. We needed to use an offset rivet set to reach the top hole in the sides. We then installed the C/S rivets along the front of the lower doubler. Finally, we installed the machine screws using fiber nuts. It was fairly difficult to get the nuts on the screws under the spar flange. Jasson used a pair of 90 degree needle nose pliers to hold the nuts, but used his fingers as far as he could reach. I had the easy job of turning the screws from underneath. Once finished, I replaced the parts that were removed.

The last two screws on the outside of the tunnel will be installed with the side skins. The skins overlap these holes.

23 Aug 2016 (2 hours, total time to date: 2232.0 hours)

I had been thinking about the best way to attach the forward side skins to the stringers/doublers. The channel stringers/doublers are 0.040 in. thick, and the skin is dimpled. I didn't want to knife-edge the doublers, but wasn't sure how well the dimples would set for these thicker layers. So, I gave it a try on some scrap. I dimpled the material, nested the dimples in the 0.040 pieces, and re-squeezed them together to be sure they were nested. I added the 0.032 layer and seated it to the stack. Then, I installed a -4 solid rivet, cut across the C/L, and finished it enough to look at the interface. It really looked good. I sent a picture to my FAA-DER friend in GA, and he told me to give that a try with a blind rivet. I did, and it also turned out well. He has been telling me not to worry so much about using blinds. I'll add a picture below.

Since that worked so well, I dimpled the holes in the doublers that attach to the stringers. Because of the bend in the upper doubler, I had to dimple several of those holes with my table dimpler.

25 Aug 2016 (2 hours, total time to date: 2234.0 hours)

I removed the canopy strip on the top of the IP and drilled out the 4 attachment holes I added through the top of the upper stringers and the upper longerons to #30. Then, I removed the upper left engine mount bolt and the left, upper stringer. I removed the remaining plastic from the stringer and de-burred/finished the stringer. I dimpled the attachment holes along the outside of the stringer. I also de-burred the attachment holes for the canopy strip on the IP and all of the holes that were accessible on the firewall flange. I dimpled the -4 holes in the firewall and IP flanges. Finally, I dimpled the #8 holes in the firewall and IP flanges.

26-27 Aug 2016 (2 hours, total time to date: 2236.0 hours)

I clecoed the left upper doubler to the left stringer and seated the dimples between these two layers. Then, I replaced the canopy strip on the IP flange and seated these rivet and machine screw holes. Finally, I marked the canopy strip to have a straight edge, removed the canopy strip again, trimmed and finished the edge, and replaced it on the IP.

1 Sep 2016 (3 hours, total time to date: 2239.0 hours)

I drilled the #8 nut plate attachment holes along the canopy strip at the IP. I replaced the upper, left stringer on the air frame, and removed the upper, right stringer. I removed the protective plastic from the right stringer, de-burred the holes/edges, dimpled the attachment holes, de-burred the attachment holes on the right side of the firewall, dimpled the right firewall attachment holes, and replaced the upper, right stringer on the air frame. Finally, I replaced the cowling attachment strip on the upper portion of the firewall and set the #8 attachment holes between the strip and upper firewall flange.

2 Sep 2016

I picked up my canopy Plexiglas today at Airplane Plastics, Tipp City, OH. Very nice people. Jeff gave me a tour of the place (showed me how they form the canopies) and gave me some instruction on drilling the attachment holes. He also gave me some drill bits and cleaning products. I wish they made other parts.

I got the Art Irvine canopy. Jeff can't sell the standard canopy direct, but I like this one better anyway - a lot better visibility.

3 Sep 2016 (5 hours, total time to date: 2244.0 hours)

I drilled the #8 nut plate attachment holes through the upper portion of the firewall flange and the cowling attachment strip. I had to remove the upper engine mount bolts again to gain access to the corners. I removed the canopy and cowling attachment strips and de-burred/finished them. I also de-burred/finished the attachment holes in the IP and firewall flange holes. I also trimmed the upper ends of the IP stiffeners to allow room for the rivet squeezer or bucking bar. I de-greased/primed the inside edges of each strip where it will interface below the upper stringer deck. These areas will be riveted to the side skins and will be done at a later date. I then mixed up more sealant and applied it to the inside of the canopy strip. I replaced this strip and rivet the #8 nut plates and -4 rivets through the strip and IP flange.

4 Sep 2016 (2 hours, total time to date: 2246.0 hours)

I de-greased the upper firewall flange, mixed up more sealant, applied it to the outside of the upper firewall flange, & replaced the upper cowling strip. Then, I riveted the #8 nut plates and -4 rivets around the upper firewall flange. the holes below the upper stringer deck will attach the forward side skins, so the -4 rivets were not driven in those holes. Once the riveting was finished, I replaced the upper firewall stand-offs & bolts through the engine mount bolt holes. This picture was taken before the stand-offs were replaced.

5 Sep 2016 (1 hour, total time to date: 2245.0 hours)

I cut a 27 inch piece of plastic tube to simulate the brake line from the master cylinders to the BH fitting. I laid out the location for Adel clamps at two locations on the lower stringers to secure the brake lines. Then, I removed the lower stringers and drilled #13 holes for the -3 nut plates (I'll ream these to final size later).

6-7 Sep 2016 (3 hours, total time to date: 2248.0 hours)

I decided to use small 0.040 thick doublers at the forward attachment points for the Adel clamps. The load going through the lower stringers will transfer to the skin along the rivet line. Since the load in the stringers can still be high at the forward end (there are only 4 rivets ahead of these holes), I thought it would be prudent to use a small doubler with a -4 rivet on each end to reduce the local stress around these holes.

I fabricated the doublers, drilled #13 fastener holes, drilled pilot (#41) attachment holes for the nut plates and -4 rivets, and trimmed them to fit in the stringers. I reamed the fastener holes in the doublers and stringers to 0.188 and attached the doublers to the outside of the stringers. I then match-drilled the nut plate and rivet holes through the stringers. Finally, I drilled/reamed the rivet holes out to #30, removed the doublers, and de-burred/finished the doublers and stringers.

8-10 Sep 2016 (5 hours, total time to date: 2253.0 hours)

I dimpled the attachment holes in the lower stringers, It was better to get this done before installing the nut plates and small doublers inside the stringer c-channel. Then, I installed the nut plates and doublers using PRC (just because I have plenty of it, and it will keep water out of the doubler/stringer interface). While that was curing, I went back to work in the forward fuselage. I reattached the return spring and rudder cables to the rudder pedals. I also replaced the master brake cylinders and cut spacers from some 3/8 4130 tubing. The spacers will keep the master cylinder push rod in proper position in the 1/4 inch bolt on the toe of the brake pedal. I finished the spacers and sprayed them with corrosion protection oil (CorrosionX). Finally, I replaced the left lower stringer on the air frame and used the tubing I cut earlier to determine the length of brake line needed to run from each master cylinder to the elbow BH fitting on the forward fuselage.

11 Sep 2016 (2 hours, total time to date: 2255.0 hours)

I mixed more sealant to apply attach a SS washer to the inside of the right, lower engine mount. The other three are still attached to the fittings from the initial installation of the fittings on the stringers. I used sealant between the steel and aluminum, and those washers stayed put. I had to trim the edges of each washer to fit, and I want them to stay in place. Then, I drilled the #8 nut plate attachment holes at each #8 dimpled hole through the side skins and upper stringer doublers.

17 Sep 2016 (4 hours, total time to date: 2259.0 hours)

I replaced the lower stringers on the air frame. Then, I replaced the right skin on the air frame and drilled out the brake line pass through hole to 0.375 inch. Then, I replaced the left, forward skin and drilled out the pass through to 0.375 inch just above the lower stringer in front of the main spar. I then replaced the fuel tank and drilled out the 3, existing attachment holes to #13, and reamed them to 0.188 inch for AN-3 bolts through the upper doublers/stringer channels. I then decided to add two more AN-3 attachments between the existing holes. I was going to have to add some rivets between the upper doublers and the stringers anyway, so the added bolts will server double duty and won't be much of a weight penalty. I laid out these holes and drilled/reamed them. The picture below was prior to drilling the additional attachment holes.

21 Sep 2016 (1 hour, total time to date: 2260.0 hours)

I would rather dimple the upper skin attachment nut plate holes through the left and right forward skins, but it would mean a C/S knife edge condition in the doublers. So, I set up my C/S cage to C/S the nut plate holes in the side skins for 1097-3 rivets. This has worked well in all of the other areas in 0.032 skin (doesn't leave a knife edge). I C/S all of the nut plate attachment holes on each side.

22-23 Sep 2016 (2 hours, total time to date: 2262.0 hours)

I drilled the #10 nut plate holes along the upper stringers. These attachment holes are for the fuel tank. Then, I C/S the nut plate attach holes for a 1097-3 rivets.

24-25 Sep 2016 (3 hours, total time to date: 2265.0 hours)

I removed the right and left forward side skins & de-burred the pass through holes for the brake lines. I also de-burred the holes through the main BH doublers. I removed the upper stringer doublers & de-burred the fuel tank attachment holes. I went over the doublers one last time before de-greasing and applying a light coat of etching primer on the mating surfaces of the stringers and doublers. Once the primer had dried, I replaced the doublers. I will begin installing the fuel tank nutplates tomorrow.

26-27 Sep 2016 (3 hours, total time to date: 2268.0 hours)

I riveted the 10 nut plates along the top edges of the upper stringers/doublers. As I explained in the last entry, these fastener holes are to secure the fuel tank so that the tank can be easily removed after removing the upper skin. The tank will pull straight out of the top once the fuel/vent lines have been disconnected.

The c-channel stringers made it more difficult to set the rivets since the lower legs block the line of sight. I was able to use my pneumatic rivet squeezer, but had to grind the head of a #10 machine screw to allow sufficient clearance for clecos and the rivet set. I cut/polished a piece of 4130 tubing as a spacer so that I could engage a few threads in the nut plate to pull them up to the stringers and avoid additional wear on the nut plates. This also limited the torque required to fully engage the screw in the nut plates. This was a slow process, but I'm happy with the results.

28 Sep 2016 (1 hour, total time to date: 2269.0 hours)

It looks like I have finally reached the point where I can rivet the forward skins on the air frame. I want to use sealant along the tunnel interface, so I need to wait until I can devote enough time to get everything done in one session. Jasson can't come over for a couple of weeks, so I decided to start working on the canopy. I cut a strip of cardboard to wrap around the turtle back and extend over the cockpit to define the upper surface of the aft canopy frame. Then, I used this reference to create a template for the aft canopy frame.

29 Sep 2016 (1 hour, total time to date: 2270.0 hours)

I cut another cardboard strip to wrap over the top of the IP, and made a template for the forward canopy frame. I have ordered material for the canopy frame and am waiting for it to arrive.

Effect of Fuel Tank Sealant on Lap Joint Strength

I have seen information that fuel tank sealant in the joint faying surface will reduce static strength of the joint. Well, this is a concern for me since I plan to seal a portion of the wing leading edges to extend range. Not having sealant in the faying surface would seem to make it more likely for a tank to develop leaks. So, I ran some tests at work for some simple specimens with 2, AD426-4 rivets to see for myself.

There does appear to be a significant total effect, but for practical purposes, I don't see a real issue. In either case, the lap joints exceeded the ultimate rivet shear strength (~334 lb. each) as well as the calculated bearing strength for the 0.032 thick 2024-T3 material (~400 lb. each). There was no significant difference up to 500 lbs (250 lbs/rivet), which is above 2/3 of the ultimate rivet shear strength. The beneficial effect of friction and the dimple itself can't be easily accounted for, so it is a good idea not to count on it. I assume that the sealant allows out of plane bending to occur sooner, but is still above what most would consider the limit strength of the rivet.

9 Oct 2016 (3 hours, total time to date: 2273.0 hours)

I went back to work on the rudder pedal/master cylinder attachments. I want to have this finished before closing up the forward fuselage. I replaced the fiber nuts with castle nuts/cotter pins on the lower attachment for each cylinder. I also installed 1/4 castle nuts/cotter pins on the rudder pedal pivot bolts. Finally, I trimmed/finished the 4130 tube spacers for the master cylinder piston rods and installed the 1/4 inch bolts with castle nuts/cotter pins.

10 Oct 2016 (2 hours, total time to date: 2275.0 hours)

I degreased and applied a light coat of self etching primer to the mating surfaces of the forward side skins/doublers/stringers. Then, I replaced the left forward side skin in preparation for final assembly.

11 Oct 2016 (4 hours, total time to date: 2280.0 hours)

Jasson came over and we got to work riveting the left, forward skin on the air frame. It took longer than we expected. We started along the upper stringer and worked our way down each side. I had forgotten to remove the covers for the engine controls to allow access to the rivet tails along the main BH flange. I removed them and worked around the structure that I had permanently riveted in place earlier. I wrote about this earlier, but I am using AD470 rivets along the main BH flange because there are 4 layers of material (two skins, doubler, and BH flange). It would be a bit much to try to seat 4 dimpled layers. Also, I decided to use 4, AD470-5 rivets in the first 4 holes above the main spar. I had already enlarged 3 of them because of a damaged hole and I also wanted the ability to carry more load into the doubler/skins as the load moves up the flange. I have more than enough hole edge distance for this change. Again, this is not to be considered to be an official mod, just something I decided to do.

15-16 Oct 2016 (5 hours, total time to date: 2285.0 hours)

Installed the #8 nut plates along the top of the left, forward skin. I also continued working on the canopy frame. I finished cutting out the fore and aft stiffeners from 3/16 thick 6061-T6 aluminum. I did some finishing work on the outer edges. Also, I cut two 1 x 1 x 0.125 6061-T6 angles to fit along the upper longerons.

19 Oct 2016 (3 hours, total time to date: 2288.0 hours)

Jasson came over to help me continue riveting the forward skins on the air frame. We finished the two rows of rivets along the lower stringer/doubler as well as the 4 remaining button head rivets on the main BH doubler on the left side. Then, we replaced the right, forward skin and riveted the two rows along the right, upper stringer/doubler, and the two rows along the main BH/BH doubler.

20-22 Oct 2016 (3 hours, total time to date: 2291.0 hours)

I continued working on the canopy. I cut some wood spacers to allow me to clamp the canopy stiffeners in place on both BHs and traced a trim line along the upper edges. I also replaced the seat back and fastened a 2x4 (trimmed about 3/4 in. off one edge) to a scrap piece of plywood to simulate the seat back parachute. I climbed in the cockpit to see how my head/helmet would fit in relation to the rear canopy stiffener. I also needed to check to see how my canopy opening idea would allow the stiffener to clear the edge of the turtle back.

28 Oct 2016 (2 hours, total time to date: 2293.0 hours)

I fabricated a mock-up of the upper longeron along the cockpit so that I can experiment with my articulated canopy attachment before I do any drilling on the air frame.

29 Oct - 4 Nov 2016 (10 hours, total time to date: 2303.0 hours)

I continued work on my prototype canopy opening/closing mechanism. I want something similar to Art Invine's Midget, but I don't want to deal with bungee cords to secure the canopy.I fabricated the fittings, attached the main fitting to the longeron mock-up, checked the geometry, and cut the actuator arms to length. I decided to go with a 3/16 steel rod and thread each end on the mock-up. I used a short piece of wood to simulate the bottom of the canopy frame to asses any problems with the canopy in the retracted position. So far, so good, however, I think I need to shorten the tension rod about 0.25 inch to decrease the angle of the canopy when retracted.

5 Nov 2016 (4 hours, total time to date: 2307.0 hours)

I installed the nut plates along the upper right stringer and the AD426-4 rivets along the right firewall flange between the upper and lower stringers.

6 - 7 Nov 2016 (3 hours, total time to date: 2310.0 hours)

I marked/removed the aft canopy frame stiffener for a little more trimming. I want to be careful to get a good fit to the turtle back. I cut a 2.5 in. wide strip of 0.050 in. thick 6061-T6 to serve as the rear canopy frame doubler. This will wrap around the stiffener and allow attachment of the 0.032 in. thick canopy frame for final attachment of the Plexiglas. I used an English wheel (loaned to me by Jasson) to form the doubler strip to fit. It looks like I'll need a little more trimming of the stiffener, but I'd rather do this in smaller increments to be sure I get it right.

8-13 Nov 2016 (9 hours, total time to date: 2319.0 hours)

I continued working on the canopy frame. I cut a strip of 0.050 6061-T6 aluminum and shaped it on the English wheel to fit around the forward canopy stiffener. I also did more finishing work on both stiffeners to match the contour at each BH. Jasson came over on Sunday (13 Nov) to help me nearly finish riveting the forward side skins. I still need to install more structural machine screws at BH73.75 and a few more rivets at the bottom of the firewall flange.

Jasson got in the airplane to see how it fit. Looks pretty, pretty good. :-)

14-15 Nov 2016 (2 hours, total time to date: 2321.0 hours)

I cut notches in each side of the canopy frame for the fore and aft 3/16 in. thick canopy stiffeners. This will make for a good/tight weld joint. I marked the notches, cut them with my pneumatic cut-off wheel, and finished them with needle files. I replaced the canopy frame sides to check the fit.

16-17 Nov 2016 (2 hours, total time to date: 2323.0 hours)

I trimmed the ends of each canopy frame rail to allow space for the doubler strips. I'll need to attach the canopy skin to the 0.050 thick doublers to follow the curvature of the air frame. I also did a little more finishing work on the canopy frame stiffeners.

19 Nov 2016 (4 hours, total time to date: 2327.0 hours)

In order to have the canopy frame welded, I need to support the frame so that I can remove it and take it to the welder. I bought a 6 ft piece of 1.5x1.5x0.125 aluminum angle stock. I laid out a location along the aft end of the rails that would allow space for welding the stiffener to the rails, and drilled two, #40 attachment holes (spaced 0.875 in.) in each rail. I cut/finished two 1.5x1.5x0.062 angles to attach a piece of the angle stock across the rails. I bent the angles slightly to account for the fore/aft taper of the rails. I match drilled the attachment holes through the rails/angles. I cut the angle stock for the cross member and trimmed it to fit. I marked the location of the attachment holes on each angle for the cross member and drilled #40 holes through the angles. Then, I cut pieces of 0.090 aluminum to overlap the side skins to rivet through the rails to hold them flush with the skin. Finally, I clecoed/clamped the pieces in place.

20-23 Nov 2016 (5 hours, total time to date: 2332.0 hours)

I fabricated an angle to serve as the forward cross piece to hold the canopy side rails in place. The process was the same as described above. I also laid out/drilled the attachment holes in the cross pieces to attach to the angles and match drilled them in place so that I could cleco the components together.

24 Nov 2016 (2 hours, total time to date: 2334.0 hours

I removed the cross supports and drilled attachment holes through the cross supports for a plywood shear panel. I then riveted the cross-supports to the angle brackets and through the canopy side rails.

25-27 Nov 2016 (3 hours, total time to date: 2337.0 hours)

I cut a piece of plywood to size, clamped it in place under the cross supports, match drilled the attachment holes through the supports. I then removed the plywood, placed it on top of the supports and used AN3 bolts to secure it to the supports to hold the canopy frame in place and prevent any shifting in the horizontal plane. I also did more finishing work on each canopy stiffener.

28 Nov 2016 (3 hours, total time to date: 2340.0 hours)

I fabricated tw0, 0.062 thick angle brackets to attach to each canopy frame stiffener. They will allow me to attach the 0.050 thick strips and a piece of aluminum angle between each stiffener to secure each end for welding. I'll attach the aluminum angle with machine screws so that I can remove it when I install the Plexiglas. I'll also rivet the brackets with -3 rivets so that I can remove the brackets, trim them, and replace them with -4s after the welding is finished. I also fabricated an extension for the forward bracket, bent a flange for stiffness, and riveted it to the bracket. Finally, I drilled the #40 pilot hole in the forward bracket, clamped it to the forward canopy stiffener, and match drilled the hole through the stiffener.

1-2 Dec 2016 (4 hours, total time to date: 2344.0 hours)

I trimmed the aft angle bracket to fit the aft canopy frame stiffener and cut the remaining 0.125 think aluminum angle to attach to each bracket (fore/aft) to hold the stiffeners in place for later welding. I trimmed/finished the angle to fit, drilled pilot attachment holes, and match drilled it in place. I then removed the stiffeners and trimmed/finished the inside of each stiffener. The aft stiffener must clear the turtledeck as the canopy is raised/lowered. I then replaced the parts on the airframe.

3-5 Dec 2016 (9 hours, total time to date: 2353.0 hours)

I fabricated 18 1x1x0.062 angle brackets to use as shear clips to attach the canopy frame strips to the fore and aft stiffeners. I cut/finished them to 5/8 width. I installed them by drilling pilot holes in each leg, clamping them in the corner, and match drilling through the stiffener and strip. I installed three on for forward side of each side of the rear stiffener, then installed three on the aft side of the rear stiffener. This will hold the aft strip securely to the stiffener for later welding. I then marked/removed/trimmed/finished the aft attachment strip to lay flush along the side of the canopy rails.

6-9 Dec 2016 (4 hours, total time to date: 2357.0 hours)

I called a local welder and he came over to take a look at the canopy. He ended up giving me the name of another local welder who is very good at TIG welding aluminum. I gave him a call, and once I'm ready, I'll take it over. I returned to work on the forward stiffener. I laid out the locations for the angle brackets, clamped them in place, and match drilled them one by one. It took a little longer then the rear stiffener because of the space constraints. I installed 3 brackets on the aft side of the stiffener on the left and right. Once this was done, I trimmed the attachment strip to approximate shape. I left it slightly large so I can carefully finish it later.

10-11 Dec 2016 (8 hours, total time to date: 2365.0 hours)

I fabricated two more angle brackets to install on the forward side of the forward canopy frame stiffener (on each side) to help hold the attachment strip in proper alignment for welding. I installed these brackets (took a bit of time), and did more work trimming/finishing both attachment strips. I also tweaked the strips as needed with the English wheel. I trimmed the fore and aft stiffeners to account for the thickness of the attachment strips near each side rail. The final fit looks very good to me. I just need to be sure to ask the welder to be sure the strips are flush with the outside of the rails when welding them. I also cut the lower corners of the forward canopy attachment strip. I know I will need clearance here for the plexiglas, and I will be able to finish the required trimming when I fit it. The corners give me some room to make this final trimming easier. Once this was finished, I drilled out the attachment holes at the brackets on each end of the canopy (where the upper angle stock attaches) for #8 machine screws. I cut a piece of plywood to maintain the proper spacing of the canopy stiffeners. I drilled/reamed holes along the upper angle that I am using to hold each stiffener in place, bolted the plywood in place. I then added a piece of 1x2 on the horizontal plywood and screwed the other piece to it. Now, the frame can be removed and taken to the welder.

I'm on-hold right now as far as the canopy frame goes. I've got an appointment with a welder on Monday morning. However, doesn't it look nice sitting there on the bench? Everything seems to have worked out well so far. The English wheel was a big help with the 0.050 thick sheet. The fit looks pretty good. :-)

17-18 Dec 2016 (4 hours, total time to date: 2369.0 hours)

While waiting for the canopy frame to be welded, I decided to work on the fuselage top skin. I want to add a spacing strip at the main BH - mainly to allow a better transition for the canopy. The canopy and fuselage skin are 0.032 thick, so that leaves nothing for any type of "seal" under the canopy sill. Also, adding a strip here fills the gap where the side skins overlap the attachment strip at the IP. So, I cut a strip of cardboard to make a template for the strip to fit the curvature and transferred it to a piece of 0.040 sheet. I cut the strip (a little wider than needed - just in case) and formed it to fit with the English wheel (I'll trim/finish it to what I need later). I then fabricated a strap hole finder to allow me to locate the dimpled attachment holes along the top of the IP. I used some scrap 0.025 aluminum, dimpled for a #8 machine screw. For the drilling guide, I used a piece of 0.050 steel. Once I had the hole finder match drilled (#21 hole), I reamed the aluminum to 0.162 and dimpled it for a #8 C/S screw. The procedure I used was to use a brass machine screw to attach the aluminum strip to a given hole, clamp the strip in place, cleco the steel guide in place (with a 0.040 spacer), and drill a #21 hole in the strip. Of course, the screw will be, well... screwed (damaged) in the process, but can be easily removed and thrown away. This works well, and I drilled four of the attachment holes so far.

19-23 Dec 2016 (5 hours, total time to date: 2374.0 hours)

I took the canopy frame to the welder and it took them about 3 hours to weld it up. I think they did a great job. They had to grind a few areas along the top of each 0.050 inch thick strip where the welds came through the thickness. Once I got it home, I spent time sanding/polishing the welds on the outside (at each corner where the stiffeners attach to the sides) flush. This took several hours. Then, I removed the supports (I left the two lateral supports on for now). I'll wait until the weather warms up a little before fitting the canopy skin and Plexiglas.

As far as I know, this is the only all alumium canopy of it's kind on a Midget Mustang. All of the standard canopies I've seen are welded steel tubing with aluminum skin attached. I'm happy with how my design is coming along.

25-26 Dec 2016 (3 hours, total time to date: 2377.0 hours)

I finished drilling the attachment holes around the top skin doubler strip and marked/trimmed the strip along the forward edge of the IP BH flange. I then fabricated a cardboard template for the top skin.

27-28 Dec 2016 (2 hours, total time to date: 2379.0 hours)

I located the center of the fuel tank filler neck on the upper skin template and marked the C/L on the template. I then traced the template on a sheet of 0.032 2024-T3, and cut it out (slightly oversized). Finally, I marked the location of the filler neck on the sheet, drilled a #40 hole in this location, and marked the C/L on the sheet.

29 Dec 2016 (2 hours, total time to date: 2381.0 hours)

I started rolling the top skin with the English Wheel, but the anvil radius was a bit small and it put some minor marks in the skin along the anvil crown. I took the skin over to a shop in Dayton and used their industrial roller. It took out the majority of the marks. I also bought a set of anvils to use on the Wheel. I will need to make some minor adjustments to the top skin along each side. Otherwise, it looks pretty good. The lines in the picture are showing up because I haven't removed the plastic. At least, that's what I'm hoping. :-)

2 Jan 2017 (2 hours, total time to date: 2383.0 hours)

I laid out the rivet pattern for doublers around the header tank filler neck on a scrap piece of 0.040 sheet. I transferred the pattern to some of my scrap 3/16 thick 6061-T6 that I used for the canopy stiffeners. This will provide spacing for the fuel cap seal. I also transferred the pattern to another piece of 0.040 2024-T3 to fit snug around the filler neck below the spacer. I'll be able to use some sealant there to keep fuel out of the cockpit. I drilled the #41 pilot holes in the spacer, and match drilled the pilot holes in the top skin. I then clamped the spacer in my drill press, and cut a 2.5 inch hole in the center. Finally, I cut the outside of the spacer and finished the edges.

4 Jan 2017 (1 hour, total time to date: 2384.0 hours)

I clamped the top skin to a piece of 2x6 and used a fly cutter to cut the filler nect hole in the skin. I did a little de-burring/finishing, clecoed the spacer in place, and test fit the top skin on the airplane with the filler cap installed.

6-8 Jan 2017 (8 hours, total time to date: 2392.0 hours)

Once I could see exactly where the fuel cap was relative to the top skin, I could tell that I needed a thicker spacer to be sure that I could get the 0.040 thick ring to seat far enough on the neck to be sure it was below the top radius. I fabricated another spacer ring from some 0.090 sheet using the same methods as I used for the 3/16 spacer. I already had a template, so it wasn't too difficult. Once finished, I made sure the stack fit nicely and drilled lightening holes between the attachment holes. I suppose it didn't really make much difference, but I did it anyway. I reamed these holes to 0.249. I labeled the stack to be sure I kept everything where it was supposed to be and did more finishing work. Then, I replaced the stack on the skin and match drilled the attachment holes out to 1/8 inch. I removed the stack, de-burred the holes, and dimpled the skin. Then, I match drilled the ring stack to #30 and C/S the attachment holes in the top ring. I did the necessary final finishing, replaced the stack, and riveted it in place. I was a little concerned about the skin curvature in case since the holes in the skin might move a little as the rivets were set. I partially drove the rivets along the C/L first, then both on 90 degree line, then the aft 45 degree holes, and finally the forward 45 degree holes. Then, I finished all of them in the same sequence. I felt safer doing it this way, and it worked out very well.

Once this was done, I dimpled the #8 attachment holes in the top skin doubler strip and attached it to the IP flange. I then replaced the top skin on the air frame.

9-15 Jan 2017 (11 hours, total time to date: 2403.0 hours)

The top skin needs to have some compound curvature along the aft end to allow it to seat well at the IP flange over the doubler strip I made earlier. I decided to try using the English Wheel to stretch the skin slightly about 1.5 inches aft of the end. This will turn the aft edge inward. I practiced this on a few pieces of scrap. I used a series of anvils - working toward anvils with a smaller radius to add the curvature slowly. Once I thought I had a reasonable amount of turn-in, I replaced the top skin and started work locating the attachment holes along the IP doubler (starting at the C/L). I decided to fabricate a new hole finder with a #21 hole in the steel - just to give me a little room for any error in hole placement. Once I had the new duplicator, I started drilling the holes. It is a slow process since I had to remove the skin, screw the bottom (dimpled) piece of the duplicator in a hole, replace the skin, cleco the steel piece to the duplicator (with a 0.032 spacer), and drill through the hole. Then, I had to remove clecos, remove the skin, remove the screw in the duplicator, and continue the process. I used brass C/S machine screws, and I threw each one away after drilling since the drill bit goes into the screw. After I had a few holes done along the IP flange, I could see that I wasn't finished with the compound curve in the skin. For the skin to seat properly, I will need to shrink it slightly between the attachment holes at the aft edge. As it is now, the skin bulges up between the fasteners. I may not have stretched the skin enough, but I didn't want to take it too far. I ordered a metal shrinker and will take care of this issue later. I continued drilling the attachment holes along the IP and the firewall flange. I moved along on both sides of the C/L and after drilling the first four holes along the IP, I started drilling along the firewall flange.

Once I got to the last hole on each side of the firewall flange, I had to remove the vertical firewall supports to allow me to use the hole duplicator. Once these were removed, I also had access to the rivet holes I couldn't get to earlier. So, I installed these rivets, and returned to drilling the attachment holes in the top skin. Once the holes were finished along both BHs, I started drilling the holes along the sides. I drilled 4 holes on each side. I have six more to go on each side.

16 Jan 2017 (2 hours, total time to date: 2405.0 hours)

I finished drilling all of the attachment holes along each side of the top skin. I had to extract one screw the hard way, but that's not too bad considering the number of holes drilled. Now, I'll wait for my shrinker to arrive to finish it up.

18 Jan 2017 (1 hour, total time to date: 2406.0 hours)

My shrinker/stretcher arrived today. I used the shrinker on a piece of scrap to get familiar with it, and started working on the top skin between a few of the attachment holes along the top of the IP. I made some good progress, but need more work to get it the fit I want. I'm glad to have these new tools.

19 Jan 2017 (1 hour, total time to date: 2407.0 hours)

I finished the shrinking work on the top skin around the IP flange area. I also did a little shrinking work on the doubler strip to allow it to sit a little better as well.

20-22 Jan 2017 (7 hours, total time to date: 2414.0 hours)

Finished shrinking the top skin along the IP flange to minimize the bulging between fasteners. I did more trimming/finishing along the sides. I then dimpled the attachment holes along the doubler strip at the IP. I started at the center and worked outboard. I was very concerned about centering the dimples given the curvature in both layers. Once I had this finished, I started dimpling the holes along the firewall flange. Finally, I dimpled the holes on each side. Then, I re-attached the skin using C/S machine screws. There were a few areas that needed more shrinking, so I removed the skin and did a little more shrinking. Finally, I used Emory cloth to remove the shrinking marks, and polished the areas with increasingly finer grades of scotch brite pads on an air die grinder. Finally, I removed the protective plastic from the top of the skin.

23-27 Jan 2017

I haven't done any actual building work over the last few days. I've been getting things lined up for wing construction while waiting for some help installing structural machine screws below the main wing attachments. I checked/double checked the dimensions of the aft ribs to be sure the rear spar dimensions were correct (I've found other goofs in the plans). However, the dimensions shown on my drawings appear to be OK. I also ordered the 0.040 clad sheet and some 0.125 plate for the fittings. I have enough 0.062 material for the reinforcement. I also lined up a shop to do the bending. They have a 10 foot, 6-axis CNC bending brake. Now, I'm waiting for the material.

28-29 Jan 2017 (4 hours, total time to date: 2418.0 hours)

I fabricated the rear spar reinforcements from the last bit of 0.062 inch thick 2024-T3 clad stock that I had left. I left them about 3/16 inch long and 0.05 wider than plans - just in case things don't line up the way the plans indicate and to give me a little more edge margin at the rear spar landing gear torque tube fitting. I also cut/finished the flap rib forming blocks from some 0.5 in. thick plywood.

30 Jan - 1 Feb 2017 (3 hours, total time to date: 2421.0 hours)

I cut/sanded the form blocks for the outboard aileron ribs. I then paired all three sets of form blocks and drilled tooling holes along the C/Ls. The outboard forms for the flaps are nearly the same as the inboard dimensions for the ailerons, so I will sand them down slightly as required after I make the flap ribs. I also bought my COM radio and started work fitting it in the stack. I was very happy to see that I made the stack correctly. :-)

2-3 Feb 2017 (2 hours, total time to date: 2423.0 hours)

To install the KX97A COM tray in my radio stack, I needed to drill attachment holes through the top of the stack, dimple holes in the tray for #6 machine screws at the four corners, and fabricate C/S spacers to fit between the tray and top of the stack. I had to be sure that the hole locations would allow access for dimpling, so that added a little time to this effort. Once I had that worked out, I clamped the tray in the stack, drilled the pilot holes, enlarged them to #29, dimpled the holes in the tray, and started work on the spacers. I used some scrap 0.080 inch thick material for the spacers.

The sheet metal for the rear spars and control surface skins/ribs/stiffeners arrived. They really packed it well - the pallet weighs over 100 lbs. Most of that is the pallet and packaging.

4-5 Feb 2017 (3 hours, total time to date: 2426.0 hours)

It took a little while to unpack the sheet metal and dispose of the packing material. Once done, I went back to work on the spacers for the COM radio tray. I finished those, installed the tray in the stack, replaced the stack in the center console, and replaced the KX97A radio for the picture.

6 Feb 2017 (1 hour, total time to date: 2427.0 hours)

I did more finishing work on the inboard flap rib forming blocks. I sanded them to account for the sheet thickness.

7-8 Feb 2017 (3 hours, total time to date: 2430.0 hours)

I re-drew the rear spar based on measurements I have taken of the ribs. The root width appears to be slightly large - at least when compared to the ribs I received from MA. I made a couple of test bends of some 0.040 scrap to check my math for the total width (to include the bend radius and flange length). Rob (Philips Sheet Metal) uses the inside measurement for his large, programmable brake. I also needed to verify the effect of carrying the bend past 90 degrees. I took the sheet material to the shop and worked with Rob to fabricate the spars. We had to scrap the first attempt, but I'm very happy with the result.

9-13 Feb 2017 (9 hours, total time to date: 2439.0 hours)

I finally finished making the flap/aileron end ribs. Since the form blocks are very thin at the tips, I thought it would be a good idea to support them with some aluminum plate. I have plenty of scrap 3/16 material that I used for the canopy frame, so I cut/finished pieces for each form block pair. Also, I used 0.5 thick plywood, so the 3/16 aluminum will accommodate the 5/8 flanges. I used #30 rivets to maintain alignment and hold the sheet in place while forming the parts. It took some time to get everything to the proper dimensions. I really hope the drawings are correct, but I'll find out soon enough. I took a picture that gives a pretty good idea of the tools I used for the entire process.

14-19 Feb 2017 (8 hours, total time to date: 2447.0 hours)

I decided to go with an IPad mini with Foreflight and Stratus 2S in my center panel. I really like this idea since it will give me geo-referenced mapping, AHRS backup, ADSB-IN weather/traffic - and can be moved to another aircraft when needed. So, I laid out the attachment holes for a RAM mount, drilled them, and fabricated angle stiffeners to attach to the mounting holes vertically on each side (four mounting holes). I ran the stiffeners over the full height of the panel and drilled 1/8 attachment holes at approx. 1 inch spacing. I dimpled these holes for 1/8 rivets and installed the rivets. Then, I replaced the center panel in the airplane and attached the RAM mount using AN3 bolts. I placed my IPad mini in the mount (I bought the RAM mount for an older mini since this allows me to keep my mini in its case - just folded back). Not a bad set-up. Then, a friend came over (Rod) to help me install two #8 structural machine screws on each side between the main BH wing attach fittings. Finally, I started work on the 0.125 thick rear spar attach fittings. I fabricated a template using some scrap 0.032 sheet to accurately lay out the fitting with the attachment hole located with a #40 hole. I then traced this on a piece of 0.125 thick 2024-T3, cut the blanks out, match drilled the attachment holes through the template, stacked the blanks, and used a -3 rivet through the pilot attachment holes to allow me to start finishing work on the blanks & be sure they are identical.

20 - 23 Feb 2017 (3 hours, total time to date: 2450.0 hours)

I continued working on the rear spar attachment fittings. I laid out the location of the attachment holes to the spars, drilled/match-drilled #40 pilot holes in each fitting, and marked the bend lines on the fittings. I also cut/finished the tapered cut at the root end of each spar. Finally, I started laying out the placement of the fittings on the spar reinforcements.

25-26 Feb 2017 (4 hours, total time to date: 2454.0 hours)

Completed work laying out the rear spar fittings on the spar reinforcements, and in turn, on the rear spars. I checked the position of the fittings on the spars (per drwg), and match drilled the fittings on the reinforcements. Actually, I did one side and duplicated everything on the other side to ensure they matched as closely as possible. Then, I removed the fittings, clecoed them together, and opened up the spar attachment hole to #13. I then bent the tabs to 7 degrees per drwg. I rounded the edge of some 0.125 inch thick stock and sandwiched the fittings in my bench vise. I placed some scrap angle stock over the tab and hit the piece with a hammer until I got the desired outcome. It was an iterative process to make sure I got it right and both parts matched. I attached the parts to the spars for safe keeping. Finally, I elevated the ends of the spars to level the attachment tabs and reamed the attachment holes out to 0.188 in. The hole in the rear spar carry through is also 0.188 for now. I want to have some leeway down the road in case it is necessary to make any adjustments to the rear spar attachments to correct any wing misalignment. I hope that won't be needed, but as an old friend used to say: "Murphy was an optimist."

28 Feb - 1 Mar 2017 (2 hours, total time to date: 2456.0 hours)

While waiting to get everything together to start on the wings, I will work on some of the remaining details on the fuselage. I laid out the attachment hole locations for the vertical fin tip, replaced the tip, & used a drilling guide to drill #40 pilot holes through the tip and attachment strip. Then, I opened these holes up to #30.

27 Mar 2017

I'm way overdue on an update. Since I recently sold my Cherokee, I don't have anything to fly. I found a great deal on a Thorp T-18, so I flew out to California, packed it in a Penske truck and drove it back home. The problem is that I now have two projects to finish :-). The T-18 is in pieces, but has an airworthiness certificate. I need to concentrate on getting it back in the air before I can get back to work on the Midget. I hope to be able to squeeze in some work on the Midget as soon as I semi-retire at the end of May.

25 May 2017 (4 hours, total time to date: 2460.0 hours)

Since my retirement party is coming up on Tuesday, I wanted to get the engine on the air frame and prepare the fuselage for transport to the airport. I want to show the Midget to everyone who will be at the party and I need room to start building the wings. I ordered the AN6-22 bolts needed to attach the engine mount to the fuselage and received them yesterday. I'm still working to get the Thorp back together, so it will be a little while before I can start on the wings.

Dan Jansen came over to help me move the engine off the stand I build to store it and attach it to the Midget. We first removed the tail cone support portion of the fuselage jig and raised the forward fuselage jig 3 inches (on two pieces of 2x4) so that I can install wheels on the jig to make it easy to move. Now that the fuselage is essentially completed, it is structurally sound and ready for the engine. The engine mount fit easily on the air frame. It helped a lot to have the other firewall on the stand so that everything was all set up for the move.

4 Sep 2017 (8 hours, total time to date: 2468.0 hours)

Started work building the wing jig. I glued pairs of 2x4 lumber together to become essentially 4x4 posts for the jig. I bolted a 2x4 to the floor and installed the center post vertically. I then cut/finished 3/16 thick pieces of aluminum to support the main spar fittings for each wing. I riveted 0.062 angle stock to these fittings to attach horizontal plates for the main spar fittings. I attached the finished parts to the center post aligned horizontally.

30 Sep 2017 (4 hours, total time to date: 2472.0 hours)

I cut/finished a 0.090 thick aluminum plate to support the right wing main spar fitting on the center post. This will attach to the angle stock on the center post. I cut this plate to match the 65 degree angle of the spar flange so that it will fit against the flange. I placed/fastened the wing tip support post in position to support the far end of the right spar. I drilled/clecoed the plate to the center post and laid out the position for the upper spar attach hole. I drilled/reamed this hole and temporarily placed the right spar on the jig.

14 Jan 2018 (2 hours, total time to date: 2474.0 hours)

Drilled out the attachment holes in the right main wing support to 0.162 in., installed nut plates in the angles, and fastened the support to the angles. I replaced the right wing spar on the jig.

25 May 2018 (4 hours, total time to date: 2478.0 hours)

Cut/finished aluminum spacers for both wing spars. These spacers will fill the gaps between the spar caps at each rib location.

28 Oct 2018 (3 hours, total time to date: 2481.0 hours)

Fabricated a shear clip from 0.032 thick 2024-T3 to attach the outboard rib to the right wing spar. I drilled #40 holes in the clip and match drilled it to the spar. I then drilled out the holes to #30 and riveted the clip to the spar. I left the #40 holes in the upstanding leg to attach the rib at a later date.

1 Dec 2018 (4 hours, total time to date: 2485.0 hours)

I laid out the rivet locations on each tip rib and used fluting pliers between these locations to flatten the ribs. I've spent a good amount of time thinking about the best way to align the tip ribs on the jig. The plans call for 2 inch long spacers bolted to the ribs and some angle stock at the vertical support. I've had my share if issues when I've tried to follow what the plans have to say in regard to jigs. In this case, once the skin is on the ribs, removing the spacer bolts will be a problem. Also, there is very limited space between the lower rib attachment hole and the rib flange. Another issue is how to check the vertical alignment of the tooling holes in the ribs once the spacers are attached? I decided to use 3/4 inch 0.062 angle stock to attach to the ribs at each tooling alignment hole using #10 nut plates (they weigh next to nothing) in the ribs. Because of the stiffening beads in the ribs, I couldn't install a single piece of angle stock between the holes. Instead, I cut two pieces of angle and drilled 0.188 holes in each piece using a fence on my drill press to ensure the the holes were equally spaced from the upstanding legs. This ensures that the upstanding legs will be equally spaced from the tooling holes and I can check the vertical alignment using the upstanding legs since they will be parallel to the tolling holes. Next, I cut a 2.25 inch strip of 0.062 sheet to attach between the upstanding legs of the angle stock and the jig vertical support. I also attached another piece of the angle stock to the strip to be sure it will remain flat. I will be able to check the vertical alignment of the ribs along this strip and adjust the alignment along the other two axes at the support. I'll have to deal with the rivet tails at the shear clip attachment to the rib, but this will be fairly easy to handle (just machine some space in the angle), and it will be easy to remove the rib from the jig after the skin is attached (simply remove two #10 screws).

I riveted nut plates in the right tip rib tooling holes, cut another piece of 0.75x0.75x0.62 angle stock to fit between the attachment angles in the right tip rib, riveted it to the attachment strip, and riveted the attachment strip to the two attachment angles. I pre-drilled the attachment angles, fastened them to the rib with a #10 screw, and used cleco clamps to hold the angles in place on the strip since they could not be drilled when attached to the rib. I match drilled #30 holes through the attachment angles/attachment strip, riveted them, and re-installed the stiffened attachment strip to the right tip rib.

16 Dec 2018 (3 hours, total time to date: 2488.0 hours)

Started work aligning the right wing tip rib on the jig. I double checked to be sure the spar was level in the jig and used a piece of 1x2 to support the spar in the center and verified the spar was not bowed and was level along the length. I clamped the wing tip to the attachment angle so that the trailing edge was 14 inches below the spar web. I attached a piece of 3/4 inch plywood to the outboard vertical jig that would attach to the 0.062 attach strip that is parallel to the tip rib vertical reference line. Then, I made the necessary adjustments to be sure the tip was aligned properly in each axis. Since the spar web is located at 30% of the wing chord, it seemed odd to me that the distance from the spar web to the nose of the tip rib was approximately 9.375 inches. It should be ~9 inches since the total tip chord is 30 inches. I decided to lay out the other ribs on the spar to see how they look relative to the tip rib. When I did that, it looked like the tip rib was slightly long. It also seems odd the the tip rib supplied by MA was formed to the nose instead of being cut short like all of the other ribs to avoid the problem of out of plane deformation caused by the tight nose radius. I decided to hold off on drilling the attachment holes through the rib until I took more time to look at all of the drawings again. I removed the rib from the jig and compared it to the drawings. Sure enough, it was longer than shown in the plans. The plans show the rib cut off (dashed line) at a total length of 23 inches (9 inches from the spar web to the tip). The rib layout drawings also agree with the 14 inches from the trailing edge of the rib to the spar web (this is good since I've found other mistakes in the plans and dwgs, so it's good to have more than one reference). I also checked the other ribs and found that they match the plans. All of this stuff takes more time that it should, but better to double check everything when it comes to these plans. I cut the nose off both tip ribs to just under 23 inches total length to leave edge margin for the first skin attachment rivet and remove the out-of-plane deformation at the tip of the nose that I couldn't remove with my fluting tool.

31 Dec 2018 (2 hours, total time to date: 2490.0 hours)

I drilled 0.375 wiring pass through holes in each tip rib for wing tip lighting. I placed the holes 0.875 in. aft of the spar web since I still plan to use three nose rib bays for additional fuel and will need to run the wiring aft of the spar. I also placed the holes 1 inch above the rib C/L so that I could keep the pass through holes as straight as possible through the other ribs and remain clear of existing lightening holes in the other nose ribs. I installed rubber grommets in these holes in the tip ribs. Then, I replaced the attachment strip to the right tip rib and clamped it back in place on the spar and jig. I spent some time checking and re-checking main spar and tip rib alignment. I still stopped short of drilling the attachment holes through the rib. I want to check the vertical alignment one more time with a plumb bob and decided to call it a day.

4 Jan 2019 (2 hours, total time to date: 2492.0 hours)

I checked the placement of the tip rib on the wing spar and re-checked the spar to be certain it was level. I then ran a plumb line down the length of the tip rib mounted to the jjg post and checked the alignment in the two vertical planes. I clamped the rib to the attachment angle and match drilled the #40 holes through the tip rib and installed clecos.

29 Jan 2019 (2 hours, total time to date: 2494.0 hours)

I fabricated a drilling guide to drill 5, #40 evenly spaced pilot holes in the right main spar root stiffener to attach the inboard nose rib. I clamped it to the stiffener and match drilled the pilot holes. I then straightened the root rib with fluting pliers, clamped the nose rib in place, match drilled through the rib, and clecoed the rib in position. As part of the process, I had to cut away areas on the nose rib aft flange to allow clearance with the bolt heads holding the spar in the jig. This allowed me to seat the rear flange flush against the spar to position it properly relative to the spar. Once the holes were drilled, I cut off the entire rear rib flange since it was no longer needed and would along get in the way when installing the main spar in the center wing carry through.

9 Feb 2019 (5 hours, total time to date: 2499.0 hours)

Drilling the rear spar attach alignment hole in my wing jig was more of a PITA than I expected. The drawings aren't as much help as I think they should be. As always, I check everything I can think of and found some differences between the dimensions in the drawings and the parts I have from MA. No real surprise, but I always try to be careful. The main things here for me is to be sure that the hole ends up 11 inches from the fuselage C/L to line up with the rear spar carry through attachment hole and is along the wing reference line.

To do this, I found the most help from the main spar carry through drawing. The reference points I used were the main spar wing attach holes. However, to be sure I had the hole centers properly located, I fabricated a second 1/8 thick, 9/16 aluminum spacer with a 1/8 inch center hole (used a 3/4 hole cutter with a 1/8 pilot drill to cut the spacer). I made one some time ago when I initially fabricated the spar root support for the wing jig. I then finished it to the proper O.D. to fit nicely in the wing attachment hole using my disk sander and scotch brite wheel. I just inserted a piece of 1/8 rod in the spacer and let it spin applying slight resistance until I got the O.D. where it needed to be. Then, I made a 0.035 thick stainless steel template to line up with the edge of the spar root stiffener and match drilled the centers of the wing attach holes through the spacer. This protects the holes in the spar from excessive wear and is the best way I could think of to accurately locate and drill the center holes in the template. The other nice thing is that it is easy to transfer the alignment hole to the jig by inserting the spacers in the 9/16 holes and cleco the template to the jig support through the 1/8 inch spacer holes.

After working out the geometry to find the vertical (wrt the wing carry through) at the center of the upper wing attach hole (FS 12.5), I carefully extended the wing reference line back. This was difficult because the root stiffener was in the way. However, I could also use the spar center line as a reference. After all that care, I initially drilled the alignment hole on the wrong line - oops. I discovered that mistake quickly and checked everything one more time and got it as close as I think is humanly possible to the proper location. In the end, the important thing is for both wings to be the same. My new steel alignment template will make that happen.

Finally, I machined an oval cut out in the plate slightly over 1/4 wide to allow me to set the proper distance between the main spar and the rear spar support on the jig. This distance needs to be measured flush from the face of the jig support to the face of the rear spar support. I made a reference "stick" some time ago to the length specified in the drawings and had to make a separate tool to allow me to verify that it is correct on my airplane. I was pleased to find out that it is correct. It would be very upsetting to find out later that the wings won't fit on the airplane.

The five hours here does not include the time I spent with the drawings. :-)

Here's a picture of those spacers I used to locate and match drill the main spar attachment hole centers.

17 Feb 2019 (3 hours, total time to date: 2502.0 hours)

Started working on the rear spar attachment bracket for the wing jig. The plans call for a single piece of angle stock, but it would have to be at least 0.125x2x2. Then, it would be a little tricky to mount to my 2x4s and ensure level in each direction. Also, I extended my jig attachment a little to allow more working clearance, so I would have needed a 3x3 angle and that would be even more problematic. So, I designed and fabricated my own solution using some 0.062x1.5x1.5 aluminum from Lowes Aircraft ;-). The reason for this is the lack of much of an inside radius in these extrusions. I cut two pieces approximately 6.75 inches long and two pieces approximately 2.75 inches long. I placed the short pieces back to back inside the longer pieces and riveted two pieces of scrap 0.062 sheet at the lower end. This will allow me to have a lot of material to clamp to the vertical support with plenty of room to install fasteners while it is firmly clamped in place. It will also provide a very stiff support.

I cut another piece of 0.062 sheet to fit on the top of the upper angles to provide stability and keep the upper surface flat.

24 Feb 2019 (3 hours, total time to date: 2505.0 hours)

Continued work on the rear spar attachment bracket for the wing jig. After thinking about the stiffness of the upper angles, I decided to replace the 0.062 sheet with 0.125 plate. I cut out the new piece and match drilled the existing #40 holes through the old piece to the new one. I then marked the attachment holes for the upper angles, checked to be sure the upper angle was perpendicular to the lower angles, and drilled four #40 pilot attachment holes through the assembly. I then marked the upper angle for trimming, made the cuts, and finished them. I dog-eared the upper angle between the lower angles and the top (no need for material below the line between the upper surface and the lower angles). I test fit the bracket the found the location of the rear spar attachment hole (using a plumb bob). The upper surface must be trimmed to allow clearance with the rear spar near the attachment hole. About 5/8 inch is what is needed in front of the hole. I made this bracket so the right wing rear spar hole will be on one side of the bracket and the left wing hole will be on the other side. I cut the upper surface to allow a good fit for both wing rear spars. The support in the center provides more than enough support to prevent any movement vertically once the rear spar is attached.

Finally, I reassembled the bracket, drilled out the attachment holes to #30, countersunk the holes in the top plate (must be flat here), riveted the upper angles to the lower angles, and riveted the upper plate to the upper angles.

2 Mar 2019 (3 hours, total time to date: 2508.0 hours)

I drilled four #30 pilot attachment holes in the lower angles of the rear spar support, clamped it in place on the jig, and cut a piece of 1/8 SS rod to check the distance between the main spar and the bracket at the rear spar reference hole. I wanted to be certain that the distance was correct at the hole - even though I have a measuring stick to check the distance at the center of the bracket (I cut an oval hole in the main spar support plate for this purpose). I had to remove some material from one end of the rod since a 1/8 rod won't fit in a 1/8 hole. Everything checked out, so I used some 3/4 inch self tapping sheet metal screws to hold the bracket in place and re-checked the alignment with each screw. Then, I drilled out the holes one by one to install 1/4 x 1.75 inch lag bolts (again, checking each time to be sure the bracket didn't move. While aligning the bracket, I found that I needed to shim the top against the 2x4s, so when I installed the lag screws, the lower angles buckled a little, but the upper surface remained in good alignment.

3 Mar 2019 (2 hours, total time to date: 2510.0 hours)

I hung a plumb bob from the rear spar reference hole in the main spar support to locate the hole in the rear spar support bracket. The best way I could think of to accurately locate and drill the hole was to use a scrap piece of thick aluminum plate. I drilled a #30 hole in the plate and C/S it so that the tip of the plumb bob could set just inside the C/S so I could get a good hole location and match drill through the plate. It worked out very well. I took my time to get it right and I needed to use a piece of shrink tube inside the reference hole since the cord on my plumb bob was a bit loose in the reference hole. Once I got the #30 pilot hole drilled, I opened it up to #13 and reamed it to 0.188. The final hole in the rear spar is 0.25, but I'd rather use 3/16 for now and ream it out to 0.249 later - just in case I end up with some hole wear in the building process. I did the same with the rear spar carry though fitting. An old friend of mine liked to say "Murphy was an optimist."

I also cut a piece of 0.025 sheet to sit on top of the bracket. As careful as I was installing BH73.75, it looks like there is about 0.025 difference between the left and right side on the airplane. I located the bracket so I could make up this difference between the two wings. Once the hole with drilled/reamed, I test fit the right rear spar.

7 Mar 2019 (2 hours, total time to date: 2512.0 hours)

I fabricated a shear clip to attach the rear spar to the tip rib. I had forgotten that the rear spar doesn't attach directly to the tip rib flange and the nut plate I added for the jig support leaves just enough room for the clip (barely). I ended up making a few clips until I was happy. While I was at it, I made two (one for the other wing). I also made a second shear clip for the main spar to tip rib attachment for the left wing (while I was in the shear clip business). I added two layers of painters tape to the rear spar to serve as a little spacer. When I cut the spar to final length, it needs to move up slightly. Right now, I have it clamped to the tip rib flange and it only extends ~1/2 of the flange. It's offset down due to the 7 degree angle of the rear spar. I suppose it really doesn't amount to much, but with the tape, the shear clip looks like it lines up with the bottom of the tip rib. I then taped the clip to the rear spar to hold it in place while I match drilled #40 pilot holes through the tip rib. I then clecoed the clip to the tip rib. The picture shows how much space I have at the nut plate. :-)

9 Jun 2019 (3 hours, total time to date: 2515.0 hours)

Finally had a little time to work on the wing. I drilled the attachment holes for the rear spar attach clip to the tip rib to #30. I hadn't riveted the tip rib to the main spar because some of the holes go through my jig arrangement. To solve this issue, I had to remove the wing from the jig and open up those holes in the jig to allow clearance for the rivets. I also discovered that I needed to remove some material from my jig support plate (for the main spar wing attachment) to allow the root aft wing rib web to slide between the plate and the spar stiffener. I accomplished these tasks and riveted the tip rib to the main spar attach clip. I also riveted the rear spar attach clip to the tip rib. Then, I replaced the wing hardware back into the jig. Those small issues were pretty easy to resolve and now the wing will be easy to remove when the wing is finished. An offset, ratcheting Phillips screwdriver removes the tip attachment screws. Then, I started checking the placement of the forward ribs at each wing station. After finding errors in the plans, I am always careful about trusting them without a lot of checking. Wing station 22.5 didn't work out to be 22.5 from the C/L as measured from the wing tip. It was off by about 1/4 inch and there was a rivet partially blocking the rib flange. I had to remove some material from that rib flange to provide clearance with that rivet head. Also, there is a small issue with the root aft rib as far as how I will be able to fit it to the rear spar. The rear spar parts are currently clecoed in place, so it is difficult to work out the rib attachment and drill the pilot holes in the aft flange. I decided it would be better to cut the rear rib flange off of this rib and fabricate an attachment clip that can be attached here. Then, I can attach the rib to this clip and it will be a lot easier to get the alignment right. I cut the flange off of the rib and started laying out the forward ribs.

I moved the Midget fuselage to my hangar with my Thorp T-18 and Smith Miniplane. Now, I have three airplanes in different stages of repair or construction. The miniplane had issues with the right mag and we discovered that one of the engine mount tubes had failed. We removed the engine and I sent the mount off for inspection and repair. I will also replace the old Eismann mags on the baby Franklin engine with new Bendix.

10 - 23 Jun 2019 (20 hours, total time to date: 2535.0 hours)

I laid out all of the nose ribs for the left wing to check the fit on the spar. It was necessary to move them slightly, but nothing more than about 3/8 in either way. Most of them were very close (if not on) the plans location. I started drilling the rib attachment holes at the tip end. It was much easier to start there since there is less material to drill through. I numbered the ribs 1 - 10 going from the root to the tip (rib 1 and 10 were already installed). Since I only had to drill through the 0.040 spar web for rib 9, I laid out the hole pattern on the rib flange and drilled those holes on with my drill press (clamped a piece of plywood to the base and rotated it to one side). I laid out the rib fastener line 10/32 from the outside of the rib web to help ensure that the front and rear spars remained in line across the main spar. Then, I clamped the rib in place (using cleco clamps with scrap 0.032 strips along the main spar and rib flanges) and match-drilled #40 pilot holes through the spar web. Then, I drew a matching rivet line on the tail rib and clamped it in place where the line was visible through the pilot holes in the spar. I match drilled these holes through the tail rib and clecoed both ribs in place. I was able to repeat this process for rib 8, but needed a new method as I went toward the root. As the doublers pick up, it becomes very difficult to drill a vertical hole though thicker material. I marked and drilled pilot holes in the rib spacers, checked the rib position several times, and match drilled the pilot holes through the spacer into the spar web. Then, I clamped the rib in place to line up the fastener location on the rib through the pilot holes. It was tougher for the nose ribs since I had to look up from under the spar. I used a magnifying mirror to help with this. Another problem was along the doublers. As the the doubler stacks increase, things become more difficult (as stated above). I fabricated hole templates for each wing station that I laid over the spacers/doublers. I bought a drilling guide from Avery Tool that helps drill true vertical holes. At a few wing stations, I had to remove material from the templates to fit around existing rivet heads to allow the template to sit flush. By the time I got to rib 3, I found that it worked better to match the rivet line on the spacers to the nose rib using the rib web as the reference. That eliminated the need to look up through the pilot holes in the spar using the mirror. It was very easy to look down to find the line for the tail (rear) ribs. This was a longer process than I expected, but I was being careful to check and recheck the rib placement. I also found that the tail ribs didn't always touch the rear spar exactly. I will most likely need to cut off a few of the rib rear flanges and add a new attachment angle to the rear spar. More later on this...

1 - 4 July 2019 (12 hours, total time to date: 2547.0 hours)

I fabricated the left wing main spar support plate to fit on the wing jig center support. I drilled/reamed the wing attach holes in the support plate using the template I made earlier. I also drilled the 1/8 inch pilot hole to locate the rear spar attachment hole. I then attached the new support plate on the center support and test fit the left spar. I then started working on the left spar support structure for the wing jig. The main difficulty for me was designing something that would hold the spar in place and allow me to open/close my main garage door. I built a support post for the left wing tip using 2, 2x4s (as I had done for the center and right wing tip support), put cut it to 7 feet to allow clearance with the garage door. I also glued/screwed a 1x4 to the side of the post (away from the wing) to provide more stiffness and to help keep the post as straight as possible. I then made an upper support beam from 2, 1x3 pine boards with 2x4 spacers to provide stability and anchor points for lateral supports mounted from existing garage 2x4s along the near wall. I glued 2, 2x4s together to serve as spacers and cut them as needed for the beam. I then glued/screwed the spacers to the 1x3s to form a very strong beam. I mounted the beam to the center post and the left tip post. I temporarily secured the beam laterally using a scrap piece of 1x2 from the garage wall to the post. This allowed me to get the post in position. Finally, I screwed a piece of pine to the post to temporarily hold the spar level on the jig.

10 - 25 July 2019 (15 hours, total time to date: 2562.0 hours)

I finished the work required to secure the left wing jig. I secured the wing tip post to the cement floor, fabricated and installed the lateral support beams, and finished the alignment of the left wing tip rib.

1 - 3 Aug 2019 (4 hours, total time to date: 2566.0 hours)

Working on the support bracket for the left wing rear spar attachment fitting. The same procedure was used for the right wing jig bracket using 1 inch, 0.062 thick aluminum angle from Lowes Aerospace Department ;-). I used a piece of scrap 0.125 thick 2024-T3 for the top and the spacers.

4 - 25 Aug 2019 (35 hours, total time to date: 2601.0 hours)

Finished the left rear spar support for the wing jig and installed it on the center post using the same procedure used for the right support. I then placed the right rear spar in the jig and clamped the tip to the tip rib and installed the rear spar attachment clip to the tip rib. As I did with the right wing, I had to remove the main spar from the jig to rivet the bracket to the tip rib. Then, I replaced the spar in the jig and drilled the pilot holes through the bracket into the left rear spar. I drilled these out to #30 and clecoed the rear spar to the right tip rib. I used some scrap wood to support the rear spar about 1/3 of the distance from the root. I then went to work fitting the left wing ribs to the main spar. I also did this using the same procedure used for the right wing. It still took approximately 2.5 hours per rib. This would have been a little faster since I learned some things doing the right wing, but I took some extra time de-burring/finishing the ribs. I will need to go back and do this for the right ribs, but will wait until I'm deburring the attachment holes for final assembly. All of the holes currently drilled for the right and left ribs are #40 (pilot holes). All of the ribs are now clecoed to the main spars. As I wrote earlier, it doesn't look like there is any way around the issue of the rear ribs not lining up properly along the rear spar. Some are a little short and some are a little tight. Instead of trying to line them up independently from the front spars, I decided to keep the front and rear spars in line. I will need to straighten them all, check the rear spars to be sure I have them straight (no sagging), cut the rear flanges off the rear ribs as necessary, and make new attachment brackets for the rear spars.

Just one more note here. The way the main spars were fabricated by MA, placement options for the second front rib from the root were very limited between two of the existing spar cap rivet heads. I had to trim the rear flange to provide clearance with one of the rivet heads. Alignment of the front ribs is a little tricky. I used some scrap aluminum sheet strips to clamp to the spar and rib flanges to help check alignment and help hold the ribs in place before drilling the pilot holes. I also used a 4 ft metal rule to check the alignment along the top and bottom flanges along the spar line. Checking and re-checking this added to the time required to install the ribs to the main spars.

24 - 29 Feb 2020 (6 hours, total time to date: 2607.0 hours)

Well, this has been quite a delay :-) I bought a Smith Miniplane to give me something to fly and keep my tail wheel skills sharp while I'm finishing up the work on my Thorp T-18 and the Midget Mustang. There was an "incident" with the Smith on the way home. The prop bolts worked loose and I had to leave it with some friends in Illinois. Jim Templeton is a good IA and he picked it up and trailered it back to his shop in Springfield, IL. That was back in Sep 2018, and it took until Easter 2019 to get it ready and for the weather to warm up enough for me to fly it home. When I got her home, I discovered that one of the engine mount tubes was broken (probably from the roughness when the prop came loose). Anyway, it took a lot of my time between May and October 2019 (especially between Aug and October when I got the mount back from repair. I have more info about this on the pages for the Smith if anyone is interested in more details. Between that and the Thorp, I didn't get to spend a lot of time on the Midget until now.

I had straightened a few of the smaller tip ribs, but needed to spend these hours doing more finishing (de-burring, etc) work. laying out the locations for the rib/skin rivets, and straightening the rest of the ribs with fluting pliers.

Mar - May 2020 (24 hours, total time to date: 2631.0 hours)

I've been working on the Midget on a time available basis. A lot is going on with the Thorp T-18 and I've been getting things wrapped up for the condition inspection for the Smith Miniplane.

Anyway, since the aft ribs would not line up with the rear spar (when in-line with the nose ribs), I decided to cut the rear flanges from the aft ribs and fabricate attachment clips from some scrap 0.032 sheet). I marked the vertical position for each rib on the rear spars using two plumb bobs. Then, I pulled the rear spars off the jig to lay out and drill pilot holes to attach the 0.062 rear spar doubler (~ 2 inch spacing). I left space around the landing gear torque tube attachment points. I'll drill those attachment holes later. I fabricated the attachment clips for the aft ribs and drilled pilot holes in them to attach them to the rear spar. The rule I used for the spacing was to stay above 0.75 inch, so the number of fasteners naturally decreased from the root to the tip ribs. Once finished, I laid out the attachment clips in each spar and match-drilled the clips through the rear spars and clecoed them in place. I replaced the rear spars, aligned the ribs to the rear spars, marked the aft edge of the ribs (to be sure to have adequate edge distance for the attachment to the clips), laid out/drilled pilot attachment holes through the vertical clip leg, and match drilled the pilot holes through the aft ribs. Everything is now clecoed together.

Jun - Jul 2020 (24 hours, total time to date: 2655.0 hours)

I drilled out the aft rib pilot holes and all of the existing holes through both rear spars to 1/8 inch. I removed each aft rib, de-burred the holes in the aft bracket and rib, dimpled the attachment holes between the rib/bracket, applied a light coat of primer to the mating surfaces, and riveted the bracket to the rib. I repeated this process for all of the aft ribs and replaced them on the jig. To perform this task on the inboard ribs, I had to remove the aft spar. While it was off, I cleaned up/debured all of the holes in the rear spar and doubler. I replaced the inboard ribs and rear spar on the jig.

I started laying out the WRL and C/L on the right and left ribs and rear spars at FS73.5. I'll need this information for my aileron control prototype to make sure that everything will work properly and allow me to test my bellcrank design.

Now that the ribs are all in position, I started work on the aileron bellcrank bracket that goes on the solid ribs at WS73.5. This requires some research that I didn't include in my building time. It is another prime example of measure 10X, cut once. The plans and supplementary material are terrible. All Chris did was slap some MM2 drawings in the package he sends out and leaves everyone to figure out what is different between the MM2 and MM1 in terms of how the control system is rigged. I'm going to vent a little here because this really sucks! You have to be VERY careful because the aileron push rod between the stick and wing bellcrank must clear the landing gear torque tube. I have learned over the years with this project NOT to trust the drawings completely and always take the extra time to double and triple check everything. There are many constraints in the control rod path to the stick, so planning ahead is a necessity. There are also no drawings or explanations about how to make the aileron bellcrank itself. The information in the MM1 drawings is for the old bellcrank before the change to the push rod setup. There is a Mickey Mouse sketch in the revisions/updates, but not enough information to build anything. This is just like the situation with the bellcrank for the elevator - you're on your own. So, I'll have to take the time to make a prototype to make sure everything works. Also, I found nothing about the rigging either, so I'll go with ~20 - 25 degrees up and 15 degrees down (like my Thorp T-18) to help out a bit with adverse yaw. Also, for other builders out there, this should be fairly obvious, but I wonder if it would have killed Chris to update the plans so that it is clear that you don't install the aileron counterweight tubes on the aileron spars. This was the old MM1 design, but since he includes both sets of drawings, there may be some confusion. It just seems like pure laziness on his part and since he doesn't care enough to be available to builders, I've long since given up on even trying to contact him. The new design requires a 0.032 spar reinforcement for the aileron since it is mounted with a piano hinge to the aft wing skin. The old counterweight tube will not work in this arrangement. Outboard aileron counterweights are required as shown in the MM2 aileron drawings. Rant complete.

I took some measurements on my fuselage/control stick to make sure I know exactly how the control tube must pass through the fuselage and control mounting setup. I mounted my stick bracket to the BH web instead of offsetting it up higher. This was good for giving me more clearance for the elevator control rod and more head room, but not so good for the new aileron control rod path. I'll wait until I have the landing gear torque tubes installed to triple check, but it looks like I'll be machining off some of the control bracket to allow clearance for the control rods. Luckily, there is room for this adjustment and it won't affect the structure at all. I used a wooden dowel to check the fit on my airplane.

Aug 2020 (2 hours, total time to date: 2657.0 hours)

Well over a year ago, a friend of mine in Columbia did me a big favor and made a nice CAD drawing of the landing gear torque tube (the end that bolts to the landing gear). I simply hadn't had a chance to find someone to cut/weld the parts for me. I'm not a welder and the thicker steel is hard to cut accurately without the right tools. I bought all of the parts and did some minor re-design of the nested tubes. It is also noteworthy to mention that the plans don't show the spacing required for bolt head clearance (not to mention getting a socket on it). Instead of using 3 nested 4130 tubes, I opted for 2 with a thick wall (1.625 x 0.120) outside tube. I ran it down about 1 inch further than the second tube in the plans - just to provide a little more insurance against buckling the 1.375 tube in case of a hard landing. It's a little heavier, but not significantly. Definitely a stronger platform for the gear legs.

I found a local fabrication company willing to cut out the parts and another company to weld everything. It turned out well. Next, I'll fabricate the rear spar fitting, wings, fit them on the wings, and tack weld everything in place.

Sep 2020 (16 hours, total time to date: 2673.0 hours )

I decided to change the design of the rear spar fittings for the landing gear torque tubes. The plans show a bent 4130 steel plate that accommodates a short piece of 1.5 inch 4130 tube to receive the lower portion of the torque tubes. I'm sure this can work just fine and all, but is fairly difficult to fabricate since it's not terribly easy to bend the steel plate accurately to account for the 7 degree aft spar taper, and it's also difficult to fit/align/weld the steel tube to receive the torque tube. I decided to start with a 3 x 3 inch flat steel plate, cut the short tube at a 7 degree angle, and weld it on the plate. I added two supports on each side that I bent to fit around the tube to add more weld area and provide clearance for the attachment holes. It was much easier to weld all around the base of the tube/plate interface and the supports could be welded on afterward.

I cut/finished the plates and 1.5 inch long 1.5 inch O.D. tube sections. I located the center of the torque tube on the plate and drilled a #40 alignment hole to position the plates on the rear spar of both wings. I drew 1.5 inch diameter circles to locate the tube sections around the alignment holes in each plate. I used #40 rivets as alignment pins to position the plates on the rear spar doubler and taped the edges of the plates to the spar doublers. I aligned the tube sections on the plate so that the 7 degree cut would align the section vertically to accept the torque tubes. I cut the base of each torque tube to match the 7 degree taper of the rear spar and test fit each tube on the wings. Once I checked (and rechecked) the torque tube alignment, I marked the tube sections on the plates, and checked the fit of the reinforcements on each side of both tubes. I took the parts to a local welding shop to be TIG welded. I had to clean up the inside of the welded tubes since the welding process resulted in some penetration through the wall thickness in a few places. Nothing major.

Oct 2020 (8 hours, total time to date: 2681.0 hours)

I cut/finished a piece of scrap 0.062 aluminum to provide a 25 degree angle template to check the alignment of the mounting face of the torque tubes with the landing gear legs. I want to be sure that each tube will be symmetrical. To help accomplish this, I also cut sections of 0.75x0.75x0.062 angle stock to clamp to the face of the torque tubes and the main spar to measure the 25 degrees by hanging plumb bobs from the angles on the face and measuring the distance from the alignment angle stock clamped to the main spar. I'll measure the distances over an 18 inch run and use geometry/trigonometry to get a reasonably accurate 25 degree alignment and will use my 25 degree template as a guide during the process. This way, I should get the tube alignments to match as closely as possible.

I drilled pilot holes to mount the rear spar torque tube fittings and clecoed them in place, finished the alignment of the torque tubes, and clamped them in position. I contacted a local TIG Welder to come to my house and weld the tubes to the main spar brackets.

Nov 2020 (10 hours, total time to date: 2691.0 hours)

I called a metallurgical services company (Miller Consolidated Industries) to have the welded torque tube assembly and rear spar brackets stress relieved. They did a great job and were very timely. When I got the parts back, I coated everything with boiled linseed oil. They now appear as if they had been black anodized. I then clecoed the rear spar brackets and drilled/reamed the attachment holes for AN-3 bolts.

I then began work on the forward wing skins. I ordered 4x12x0.025 2024-T3 aluminum for the skins. I only needed 101 inches of length, but this was the closest I could find. It will give me more material for something else. I began by cutting out the sheets to the pattern needed in the length direction (I'll trim the width later). Then, I started the bending process by folding over each sheet and clamping the long edges on either side of a 1x2 as shown. Be very careful handling the thin (0.025) sheet. Try to support it along the span with a board as you bend it. I ruined one sheet by allowing it to dimple while not supporting it over a large area. You can't work those dimples out enough to make the skin look right.

I used a 2x4 to make the bend in the sheets using my body weight. I formed the nose radius to be tapered from the root to the tip using my body weight as shown. There is a lot of spring back, so you have to work it a few times to get the radius to look like you want it to along the span.

I placed the skins on the nose ribs and trimmed the ends with ~0.5 inches of clearance with the jig posts. I wanted to have some overlap in case I need it later. You can't put it back.

I then trimmed the skins along the main spar flange leaving about 0.1 in. over to be finished after the attachment holes are finished and the skin can be clecoed to the frame.

Dec 2020 ( 18 hours, total time to date: 2709.0 hours)

The next challenge was how to drill the pilot attachment holes for the forward skins. You can read things on-line about drawing a rivet line on the rib flanges and the skin, drilling the rivet holes in the skin, then finding the flange rivet lines through the holes in the skin. First, this is total B.S. How can you simply draw a rivet line on the skin? It's curved and tapered. Also, as much as you'd like to say the ribs are straight and the flanges uniform - they aren't. So, I had to come up with a method that would work for me. I'm sure there are other ways, but this is what I came up with.

Since I was pretty careful to keep the forward and aft ribs in line with each other, I decided to use the lower ribs as a reference for locating the forward rib lines. The forward ribs (with the exception of rib 10) are only attached to the main spar and can freely move laterally at the tips. When the skin is over the forward ribs, it is impossible to know whether they have remained in-line with the aft ribs. In fact, you can be sure they aren't. You also don't know exactly where to drill through the skin since the taper and curvature makes it impossible to use any sort of "straight line." I decided to use drilling guide strips attached to the lower rib flanges and main spar flange to locate the holes. The first thing I needed was to lay out the attachment hole locations along the main spar for the forward and aft skins. The plans call for the normal 0.25 in. edge margin for the AD426-4 rivets with a 2 inch spacing. That means that the attachment holes would be 0.25 and 0.75 inches from the edge of the flange for the butt joint between the skins. This may sound OK, but leaves no margin for error or any gap between the skins. Of course, you want a nice and straight butt joint, but there will always be a minimum gap. The limiting factor in this are the spar cap doublers and angle brace near the root that take up some of the main spar flange area for the fasteners. In my case, there was enough room for me to use 9/32 edge margin and 18/32 between the attachment holes. This provides some room for error and enough clearance for the other structure and the rivet tails, but not so much that the skins wouldn't sit flat on the flange. I always try to remember that "Murphy was an optimist."

Since I wanted nice, straight rivet lines, I fabricated a 12 inch long drilling guide using some scrap 0.032 SS sheet. I knew I'd be drilling many holes and an aluminum guide would wear out quickly. Actually, I made two so I'd have a spare - just in case. I started with a small piece of SS and laid out two holes - one with the 9/32 edge margin and 18/32 spacing for the second. Then, I cut a 10 inch long 0.5 inch wide strip of 0.062 aluminum to act as a lip to slide along the edge of the main spar flange as a straight edge. I made sure it was straight and true and riveted it to the edge of the SS guide. I used C/S NAS1097-3 rivets for the straight edge. I then laid the small piece of SS with the pre-drilled #41 holes against the lip and match-drilled the holes at the center of the 12 inch long guide.

The next step was deciding how to space the holes along the span of the main spar between each rib. That was a little tricky since I wanted the spacing between each rib to look uniform and there is some variability in the rib spacing due to the requirement to make sure the ribs match the spar width at each location. The nominal inboard rib spacing is 10 inches and the outboard rib spacing is 11 inches. Also, the tip rib flanges face outboard for the tip cover, so the spacing there is ~11.75(-). Again, the plans talk about a 2 inch spacing, but I've seen cases in the Thorp T-18 with smoking rivets with the 2 inch spacing, so I wanted to avoid that possibility. Two inch spacing seems plenty on paper, but the results on some T-18s make me hesitate. Also, there was a recommendation to use 1.5 inch spacing after the reports of smoking rivets. Fastener spacing isn't just about strength, there are other considerations (e.g. structural stability, maintenance, and simply making sure the two pieces of material are able to conform to the desired shape). I decided to use a spacing that gave me 8 rivets between each rib. For the 10 inch spaced ribs, this works out to ~1.425 inches and for the 11 inch spaced ribs, ~1.57 inch. Between the 9th and 10th rib, I used 1.625 inches. So, on the guide, I drilled #41 holes 1.425 on each side of the centered holes, then drilled another set of holes 1.57 inches from those on each side, and finally a set of holes 1.625 inches on each side. I needed this symmetry to allow me to use the lip edge on each wing and each side of the main spar. I also attached labels on the guide to remind me of the spacing and marked the spar to help keep me from making a mistake while drilling the pilot holes in the main spar flanges.

The two red marks on the forward rib in the above picture are merely transferred from a measuring guide I made to mark the rivet lines on the rib flanges. They have nothing to do with the rivet locations along the line.

I only drilled main spar flange pilot holes at the rib lines and on either side to establish the appropriate span-wise spacing. I'll drill the intermediate holes at a later time. It was mainly important to have the rib line holes to use as part of the reference system I will use for the skin attachment drilling guide strips. I just wanted to get the spacing established now while I was thinking about it.

Next, I cut several spacers that would allow the drilling guide strips to lay flat on the 0.025 skins (with the plastic still attached). I used some scrap 0.032 aluminum for this purpose. I cut the strips approximately 4.375 x 1.5 inches and they will be clecoed to the aft ribs. Another decision that I made earlier about fastener spacing along the ribs was driven by the fluting locations required to flatten the ribs. I knew I didn't want to use the 2-inch recommended spacing, but the final choice was 1.25 inches to work around the fluting in the ribs. I wanted uniformity as much as possible, and this seemed like the best choice. You can see my green marks between the flutes on the lower rib in the picture above.

I also decided to make a uniform drilling guide for the attachment holes in the lower ribs that would be used to secure the drilling guide strips for the upper ribs. I drilled 5 pilot holes equally spaced at 1.25 inches (using my rivet fan spacing tool) in this reference guide. One hole is matched to the lower hole in the main spar flange and the remaining 4 extend down each lower rib. The four holes in each lower rib hold the drilling guide strips securely in-line along each rib location.

This picture shows the bottom side of the left wing 5th rib. The drilling guide strip is clecoed directly to the lower rib flange and the lower hole in the main spar. I used a level to ensure the ribs were vertical and used a cleco clamp to hold the rib in place while marking the fastener hole locations along the upper rib flange. Once I had established the vertical alignment, I used a fine sharpy to mark the flange edges on the strip, removed the strip and laid out the hole locations. Once this was accomplished, I marked the rib flanges through these pilot holes, removed the cleco at the lower hole in the main spar flange, and added the 0.032 doubler to the lower four strip attachment holes. This gave me a way to locate the proper location of the attachment holes in the upper skin. It should be noted here that you may be able to see why the rivet lines aren't straight along the upper rib flanges. The wing is tapered from root to tip and the curvature of the upper ribs make this more complex. The guide is the only way I could feel comfortable locating the attachment holes. This is especially true at the root rib where it is also canted to fit against the lower fuselage. In that case, I had to make the strip much wider (~3.25 inches) to follow the required curvature of this line.

I only finished fitting the drill guide strips for the lower left nose skin at this time. I will proceed with drilling the left, lower wing skin pilot holes next.

Jan 2021 (20 hours, total time to date: 2729.0 hours)

I used some scrap 3/4 inch plywood to help hold the forward skin closely around the ribs. I decided to use rib 2, 5, and 8 as the locations and traced the rib plan forms to each piece of wood. I cut them out and sanded them carefully to form rounded edges to avoid damaging the thin skin. I had to reinforce #8 simply because the scrap piece was a little short. Between clamps and these formers, I was able to get the skin fairly close to the ribs.

I will use the strip drilling guides to locate the holes in the skin, but it's not a simple matter of drilling directly though the pilot holes in the guides. There's no way to know where the ribs are with the skin over the unattached ribs. The process I am using is very tedious, but I haven't found an easier way - at least not yet.

The tip rib is fixed in the jig, so I needed to start there to be able to fix one end of the skin. I was able to directly drill through the tip rib drilling guide using a #41 bit. This established a fixed reference for the skin.

Going forward, I need to sweep down from the nose as I move toward the root rib to allow the skin to move as needed to become tight to the ribs. I don't want any buckling between rivets because I trapped the thin skin between holes. My process is to clamp the skin in place, mark all of the fastener locations using a sharpy through the guide holes, and use wide packing tape to attach the next rib's drilling strip tight to the skin. I remove the clecos on that guide strip at the lower rib, un-clamp the skin, and use a rope to lift the skin off the ribs. The rope can be seen in the picture. I slide it under the nose of the skin and simply raise the skin by pulling on the rope and tying it off. I then drill through the upper three holes in the strip guide (this way you can't drill through the rib flange in the wrong place). This does a few things to help. First, it can be difficult to find the marks on the rib flange at any single hole, and it is nice to be able to see how the marks are matching the first three skin pilot holes. In addition, the top hole is a little problematic because of the increased curvature. The idea is to pin the upper part of the rib to ensure that it is in proper alignment before drilling out the remaining pilot holes. Then, I lower the skin back on the frame, remove the rope, and clamp the lower surface to the main spar flange. The tricky part here is to make sure that the skin is in the same position it was the last time it was clamped in place. Then, I remove the tape on the drilling guide strip and cut off the upper portion (top three holes) with tin snips. This must be done since the skin will move as you drill down the fastener line and it may also be necessary to cut more off the drilling strip as you work down. I try to salvage as much of each guide strip as possible since they will be needed to hold the ribs in place as I make the guides for the upper surface. After cutting off the top three holes of the guide, I locate the marks on the rib flange through the new skin pilot holes and tape the rib against the inside of the skin (the upper side is still open at this point). I match drill (#41) the second hole down, install a cleco, and remove the inside tape. Next, I clamp the upper side of the skin and replace the wood formers. I do this because I want to be sure that the skin is as close as possible to it's final position before I start working my way down the rivet line on the back side. This may be overkill, but I want to be sure that the wing tip line doesn't shift as I work toward the wing root. It gets easier as you progress along the span since you have more clecos to hold the skin to the frame as you go. I use the marks I made through the guide holes to help align the skin, but each time you drill more holes, the skin will move slightly as it is pulled tightly to the ribs. So, for the first few iterations, I wiped off the marks between steps and re-marked prior to un-clamping for the next step. After a while, this isn't necessary since the skin is becoming more secure to the frame. Once the skin is completely clamped in place, I drill the top and third holes and install clecos. I start working my way down the drilling guide strip and stop a little past 1/2 way down. I then move over to the previous rib line and finish working down to the bottom hole in the main spar flange. This is only done to help secure the skin to the spar temporarily. I don't do this until I'm sure that the skin is tight against that rib. This area will be trimmed off later, but it serves a purpose right now. I move down and toward the root in a diagonal manner to allow the skin to have a place to move toward a free edge.

I finished drilling all of the #41 pilot attachment holes in the lower, left, nose skin. I left approximately every other hole clecoed in the lower side of the nose skin and started work making the drilling guide strips for the upper side. With the lower side in-place, the ribs are fairly well secured. It's not easy marking the strips to find the flange drilling line. I started out trying to measure the distance from each edge, but ended up simply running a fine sharpy marker along the inside of the strips. It gets more difficult near the nose, but it's workable. I also ended up making duplicates when I realized that some of the holes were a little off. I marked the flanges through the drill guide holes to check the location of each attachment point. For the most part this method worked the first time, but I had to re-make one guide four times before I was satisfied.

Feb 2021 (24 hours, total time to date: 2753.0 hours)

I finished all of the drilling guide strips for the left, upper nose skin. Then, I clamped the skin back in place along with the three plywood formers. I realized that I needed more formers to hold the skin closer to the ribs. There is more spring-back with the 0.025 skin material than I imagined. I made four more formers to help with the process.

I replaced all of the strip drilling guides with the 0.032 spacers to each lower rib and started match drilling the #41 pilot attachment holes through the skin. I started at the tip rib as I had done with the lower side and worked my way accross and down to sweep the skin along the ribs to avoid any skin buckling as the skin pulls tight to each rib.

Finished the left, upper nose skin pilot attachment holes!

Started working on the nose skin for the right wing. I used the same process that was used for the left skin starting with the lower side. Once the lower side was complete, I proceeded to fabricate drilling guide strips for the right, upper side of the nose skin. The only thing to note in this process was that I paid close attention to maintaining symmetry with the left wing. I checked several times to be sure that the distance between the main spar web and the nose of the skins were matched as closely as possible. I finished fabricating 6 of the 10 drilling guides for the upper, right nose skin.

Mar 2021 (25 hours, total time to date: 2778.0 hours)

Finished fabricating the remaining 4 drilling guides for the right, upper nose skin. Then, I clamped the skin in place, replaced the plywood formers, clecoed the drilling guides to each lower rib, and match-drilled the #41 pilot holes through the guides into the upper nose skin and rib flanges using the same procedure used for the left wing.

I turned my attention to the aileron bell crank supporting structure that attaches to rib 7 (wing station 73.5). I'm concerned about clearance between the 5/8 inch diameter push rod and the landing gear torque tube. I have found enough errors in the documentation to make me cautious. I want to verify that the push rod will connect properly between the control stick and the bell crank without touching the torque tube. The drawings show the CL of the end bearing at WS73.5 to be below the wing center line. Before I start cutting the hole in the ribs, I want to be sure this will work. My initial measurements tell me this may not work. This becomes a geometry problem, so I took more detailed measurements and it looks like I may need to move the CL approximately 0.25 inches above the wing CL at WS 73.5.

To be sure about this, I am fabricating a template to match the wing spar with the location of the spar attach holes, torque tube, wing reference line, and wing center line. I will test fit the template to the air frame and attach a shortened push rod to the control stick to verify my measurements. I already have a template for the main attach bolt holes and alignment hole for the rear spar attachment (on the wing reference line). I used this to begin fabricating the wing spar template.

I also cut a hole in the approximate push rod pass through location on the lower, left root rib and test fit a length of 5/8 4130 tubing to get a feel for how this will work inside the wing.

I attached the spar template to the air frame and checked the push tube clearance with the location of the landing gear torque tube. I will need to locate the bell crank approximately 0.4 inches above the wing center line to achieve ~0.1 in. clearance with the torque tube. It was worth checking because the location shown in the plans won't work with the control stick mounted in the shear web of the main spar carry through. This is a very good example of "measure twice (at least) , cut once." A mistake here would have been very bad.

Started working on the aileron bellcrank. Because of my trust issues with the plans, I took some time to check the geometry of the sketch provided with the plans. Again, I must say that this "sketch" was very poor in terms of detail, so it was a good thing that I checked to be sure that everything made sense. The plans show the differential aileron travel as 20 degrees up and 15 degrees down. That makes sense, but I wanted to be sure that the bellcrack would provide that travel and that I would be able to adjust the travel stops on the stick control properly. Longer story short, it turns out that I need to place the stops at ~ 0.75 inch travel at the stick attachment to the push rods in each direction. That places the bolt in the center of the access holes in the control system. It takes a little effort to work the AN3 bolts through these access holes, so you wouldn't want to limit this access by limiting the stops to anything less than 0.75 inches. This works out to ~15 degrees of stick movement in each direction. Finally, I worked out the trigonometry to give me a five inch distance (longer that what is indicated on the sketch) from the pivot point to the main push rod connection to the bellcrank with a 2.2 inch distance to the push rod connection going to the aileron (this particular distance is what I estimated from the "sketch").

Apr 2021 (28 hours, total time to date: 2806.0 hours)

To make sure that my math was correct, I fabricated a mock-up of the aileron control at the 7th wing rib. I laid everything out based on where the push rod needed to be on the rib (about 0.5 inches above the rib center line) to avoid any interference with the landing gear torque tube. Also, I found that it needed to be 2.75 inches aft of the main spar web to allow up and down travel clearance at my fuselage pass through as the bellcrank pivots. This all means that the bellcrank support structure must be at an angle to the rib center line to allow a straight line to the aileron control point through the cut-out in the rear spar.

The mock-up accounted for the 7 degree angle of the rear spar and the 2.375 inch offset from the rib web to the center of the rear spar cut-out. Everything checked out to give me the 20 degrees up and 15 degrees down. I did have to move the main push rod connection 0.3 inches inboard along the 5 inch radius from the pivot point from the line drawn from the original connection points shown on the sketch. In the end, it all worked out to provide the required travel. This was a lot of work, and I wish the plans were better. It is what it is and I'm too invested to stop at this point. I just hope this blog help someone else. However, please remember to check and double check things. Depending on where you place your stick control mount and fuselage pass through, your mileage may vary :-). Honestly, I still don't know how I could have placed the stick control mount higher on the main spar carry through. Placing it directly on the web made the most sense since it was a perfect fit and allowed clearance with the flap torque tube and placed it closer to the bottom skin (leaving more available space for head room). The plans make this very confusing and it would be great if Chris would take the time to review and update the plans. There is a LOT of room for improvement. OK, enough said.

Next, I started work fabricating the bellcranks. The biggest challenge was making the slight bends in the 0.062 aluminum to accommodate the transition from the bellcrank bearing to the push rod end bearings. I cut/finished and bent the parts for both bellcranks and assembled the left one. In the end, it didn't seem stiff enough to handle the increased moment arm that I needed for the proper travel. So, I decided to make version 2.0 with a partial 0.062 doubler and shims to eliminate the bends. The spacing required for the rod end bearings is ~0.439. I had to cut and sand some 0.5 inch aluminum stock to make the spacers as well as cut out several different thicknesses of sheet stock on each side of the 0.1 inch thick aileron bearing flange.

Also, I should explain the "strange" shape of my bellcrank. I added some material that looks like a "knee" in the bellcrank opposite the push rod connection points. This will increase the strength, but mostly provide room for a rigging pin hole. Once the bellcrank is installed, it will be difficult to get things lined up properly and be sure that both wings are rigged symmetrically. It makes a lot of sense to include a way to center each bellcrank before connecting the push rods. I used a master template to make the bellcrank parts and will use it to transfer the rigging hole to the bellcrank supports and the the bellcranks. I placed the hole 1.5 inches from the bellcrank pivot.

May 2021 (36 hours, total time to date: 2842.0 hours)

I finished assembling the right and left version 2 bellcranks. I think they turned out well. The new design is a little heavier (6.25 vs. 4.75 ounces), but not bad. I like the result a lot better. You can't see it in these pictures, but I included lightening holes in the thicker spacer stock in version 1, but they only saved 5 grams each. In version 2, I was able to save some weight by cutting out smaller spacers with a single rivet on each.

It was more work, but I decided to bond the partial doublers to each bellcrank side using T-88 epoxy. It works very well and will prevent water from collecting between the layers. Yes, it was very messy and required a lot of clean up and polishing. Also, I decided to use all 12 rivet holes in the aileron bellcrank bearing flange. I know they are overkill, but they are there and I had to back rivet all of those holes. I don't have a better way to rivet anything thicker than 0.25 inches (at least without some outside help). With small parts, it seems easier to back rivet in these kinds of situations. The problem with back riveting is the reduction in strength since it's difficult to get full rivet expansion though the thickness. So, I think it's better to have the redundancy. Also, this area is very difficult to rivet because of the geometry. I needed to stay as far from the bearing as possible and I made a few small goofs on the rivet tails as a result. Having redundancy in this case is a good thing.

Finally, here is a picture comparing version 1 and version 2. As you can tell, version 1 is on the left.

Next, I began work on the bellcrank support structure attached to the 7th aft rib on each wing. I was able to verify the position of the pivot point using my aileron control tube mock-up. In order to align the tube to the aileron control and ensure that the tube goes perpendicular through the rear spar, the pivot point needs to be 1.75 inches from the rib flange. This may be different for other builders depending on your bellcrank design. This works out well for me since it will allow just enough space to insert the pivot bolt through the lower wing skin access panel. Because I had to move the location of the support to avoid interference with the landing gear torque tube, there is no room within the wing to remove/install the pivot bolt. If maintenance is required at some point, it would be a good idea to be sure this bolt can be removed without de-skinning the wing.

The plans call for 0.05 thick 2024-T3 for the support, but this will not be sufficient for a 1.75 inch stand-off. I decided to use 0.062 angle stock and attach 0.062 sheet to obtain the required stand-off.

In addition, I added two local 0.062 doublers to provide additional stiffness at the pivot point. I've run into this before, but it's interesting to note that angle stock isn't perfectly square. When adding the stand-off material, this became very clear. The stand-offs diverged indicating the angle stock was slightly under 90 degrees. I had to add a very slight bend in the stand-offs and doublers to correct for this problem. If I had this to do over, I would have bought some rectangular tubing and cut it on the diagonal to ensure the support base was 90 degrees.

As can be seen in the above image, I included a rigging pin arrangement to define the aileron neutral position. In this photo, I was also checking to be sure that the push rod attach point for the main tube was in the correct location. I later enlarged this hole to allow the tube to be removed from the wing (eventually through the tip rib). The bellcrank can rotate out of the way to allow this tube to be removed/replaced.

This image shows the bellcrank arrangement with the support doublers just prior to riveting the supports to the rib. I also used T-88 epoxy to add some strength and avoid primer or PRC between the layers. After assembly, I took a photo of each side of the rib to show the completed structure.

Another nice benefit of the pivot bolt hole doublers (triplers) is the added bearing surface area. Of course, this also means that I won't be able to use solid rivets for the wing skin on these aft ribs, but I think the benefits of the re-design far outweigh the appearance of blind rivets on the wing skin. Yes, it's heavier, but less than it may appear. It's important to me that the control system is solid, and I think this fits the bill.

Jun-Jul 2021 (25 hours, total time to date: 2867.0 hours)

I had to split my free time up a little bit between the Thorp T-18, the Midget, and a little extra flying.

I drilled out the forward skin attachment holes to 1/8 inch to make them ready for dimpling. I like to dimple 1/8 inch holes since they expand and help keep things nice and tight. I think you end up with better hole fill and slightly more hole expansion. Then, I trimmed the edges of the forward skin along the main spar flange. I used my drilling guide to fabricate spacers to set the edge distance and carefully cut along the line using a thin Dremel cut-off wheel. As indicated in the picture above, I clamped a thin piece of wood under the skin to protect the spar flange.

My landing gear legs arrived from Grove Landing Gear Systems, so I went to work getting the gear legs drilled/reamed for attachment to the landing gear torque tubes. I went with Grove since I don't have the capability to bend thicker aluminum (or steel), and I like the option for rifle drilled brake lines in the gear legs. I think it is well worth the cost.

The first thing I did was to fabricate a drilling guide to transfer the hole locations to each gear leg. I went a little overboard and made two extra guides from a master - just in case the holes were enlarged when I match drilled though the guide to the gear leg. I was pretty nervous about the process since the gear legs are fairly expensive and it takes a few months to get them. I lined up the guide on each gear leg, clamped it in place, and drilled (#30) about 0.1 inch into the leg. Then, I moved to my drill press, leveled the gear, and drilled the rest of the way through.

I progressively drilled out the holes (#19, 3/16, 1/4, 5/16, 11/32, and 23/64). At 3/16 and 1/4, I laid the legs back to back to check to be sure the holes where aligned and true. It's practically impossible to get the holes perfectly lined up in my home drill press. In my case, the holes at the "heel" of the legs worked out to be very close, so I used that hole as a reference since the legs lined up very nicely with that hole pinned. I ran a drill through the other holes to "reset" them at 3/16 and 1/4 inches. This was convenient since I could use AN3 and AN4 bolts as the pin and to pin the other holes as I drilled them.

Once I reached 5/16, it was time to match drill through each torque tube. The stand-offs in the torque tubes had an inner diameter of ~23/64, but I wanted to run a slightly smaller bit through before going to 23/64. It works a lot better to drill in smaller increments and any mismatch can be worked out a little at a time. Again, I used the "heel" holes as the reference, so I always drilled this one first. Also, I worked it through 11/32, 23/64, and reamed to 0.373. That worked very well for the AN6 bolts (I simply ran the reamer through 2-3 times and the bolts fit nice and snug). Once I had the reference hole done, I installed an AN6 bolt and went to the diagonal hole to repeat the process. It was time consuming, but it worked out well.

When finished, I temporarily mounted the gear legs on the wing jig with two diagonal bolts to see how they look. Things worked out very nicely, but I've hit my head a few times, so they may have to come back off. :-)

Aug-Sep 2021 (25 hours, total time to date: 2892.0 hours)

Again, I've been splitting up my time between the Thorp T-18, flying, and the Midget.

I finished the edges of the forward skins to be as straight and smooth as possible so the butt joint between the forward and aft skins will match nicely. Then, I decided to remove the plastic from the skins around the fastener holes using a soldering iron. I have been hesitant to do this because I was worried about scratching the skins, but there is so much surface area to deal with, I decided to give it a try. I rounded and polished the soldering iron and it seemed to work well. One thing I learned is to run the iron one way (not back and forth).

Then, I de-burred and dimpled the holes in the skin, ribs, and main spar flange. That took several hours since I had to use several different methods to dimple various areas. The edges of the skins and the main spar flange were easy to dimple using my pneumatic squeezer. I dimpled the internal holes in the skin using my rivet gun with the die secured in a tungsten bucking bar. You need to be fairly careful about the pressure used for the gun. I set it so I could watch to punch move over about 6-8 taps to make sure it was seating level around the hole. Otherwise, you end up with a smiley dent around one side of the punch. There ends up being a slight mark around the punch, but I've found it polishes out as long as it's not too deep and the mark is uniform around the circumference.

Then, I decided to make a small sample skin to fit over the landing gear torque tube bay. This way, I can experiment with the gear leg cut-out on the sample without ruining my skins.

Oct 2021 (20 hours, total time to date: 2912.0 hours)

When I fabricated the skin section last month, I was considering the possibility of cutting an access panel around the nose of that section in case it was ever necessary to remove the landing gear torque tube. After more consideration, it seems far too difficult to fit and seal an access cover around the nose of that section when there is a much simpler way to accomplish the same goal. Since the flaps hinge on the bottom rear spar flange, it will be easier to access the torque tube aft fitting through the top of the aft wing skin. If that relatively narrow access panel is extended forward, it is possible to tilt the torque tube down enough to extract it through a nose skin access panel on the bottom side of the wing. With this in mind, I made several measurements and fabricated new practice panels covering the bottom of that section as shown below.

These new panels have the same attachment hole pattern as the skin, so the final access panel doubler can be easily transferred to the nose skins. I fabricated a candidate doubler and transferred the pattern to the left practice panel and checked to verify that I would be able to remove the torque tube through this opening and could install the attachment bolts for both the torque tube and landing gear legs when the skins are finally riveted in place. In addition, I fabricated a template for a wing tie-down fitting that will attach through two of the gear leg bolts. I will need to make a bend (~30 degrees) in the tie down fittings and allow for a small opening in the access panel cover to clear the fitting as it exits the bottom of the wing skin. I'll need to provide a small cover for this opening as well on the panel covers.

Nov 2021 (10 hours, total time to date: 2922.0 hours)

Fabricated the final 0.032 in, thick access panel doublers for the gear leg cut outs. I then fabricated two 0.025 in. thick cover plates with cut-outs for the gear legs. All of the holes are still #40 since I will be tweaking (removing/replacing) the covers to work out the arrangement for the tie-down pass-thru. It looks like I'll need to add a stiffener along the lower portion of the cut-out as well as at least one in the cover. The large cut-out has a big effect on the local stiffness of the panel.

Dec 2021 (18 hours, total time to date: 2940.0 hours)

I decided to shift gears a little and started work fitting the bottom aft wing skins along the seam line. My original plan was to cut the 12 ft rolled sheet of 0.025 thick 2024-T3 sheet to rough size (including ~ 2.5 inch overhang past the rear spar). I cut a single sheet of 4 x 12 aluminum to approx. 102 inches long and cut a diagonal 18 inches wide on one end and 30 inches on the other to form the trapezoid for the tapered wing. I planned to use the sheared edge of each sheet to form seam line at the main spar. Well, that didn't work as well as I'd hoped. Over the approx. 101 inch seam line, the sheared edge didn't line up precisely. It wasn't off by much, but even 1/32 difference is too much for appearance sake (if nothing else). So, I decided the best way to proceed was to locate one hole near the 5th rib to hang the sheets and used some Gorilla tape to stabilize the skins in place, back-drill several of the #40 holes along the spar, and drilled out the holes at each rib to #30 (in the skins only). This allowed me to temporarily remove the nose skins and hang the sheets from the #30 main spar fastener holes for the nose skins (at each rib location). I then back-drilled the #40 holes for the lower skins using a 90 degree offset drill along the entire spar. The only exceptions were at rib 1 and 10 where back-drilling wasn't possible because of the jig. This worked because I used my drilling guide for all of the skin attachment holes in the main spar so both rows of holes were an exact match. Otherwise, this would have been more difficult. Once this was finished, I removed the skins and marked a trimming line between the rows of holes (approx. 9/32 from the row of #40 holes since my hole spacing is 18/32). This provides the 8/32 edge margin plus a slight amount to account for the seam. I used a Dremel cut-off wheel to make the initial cut and sanded the edge with an aluminum block sander to finish. In the end, I looked for approximately 8.5/32 edge margin along the row of #40 holes. When I replaced the skins, the seam looked very close. I have a little more finishing to do at the end ribs and a little on the nose skins, but the seam is looking very nice.

I then cut out my tie down fittings from a small piece of 0.125 in. thick 2024-T3 plate, and bent the fitting to allow the tie down to be oriented appropriately. I marked and cut out the required pass-thru in the left gear leg cover to test fit the fitting.

Jan 2022 (20 hours, total time to date: 2960.0 hours)

Continued work drilling the aft wing skin attachment pilot holes (#40) along each aft rib. I used the existing drilling guide holes in each rib and continued down using a drilling guide with a 1.25 inch hole spacing. I fabricated new drilling guides for the tip ribs using the upper holes as the reference. I back-drilled the attachment holes in the aft root ribs. Finally, I drilled the pitot mount attachment holes through the main spar flange using existing attachment holes for the lower aft skin between the 7th and 8th ribs on the left wing. I also cut the skin pass through hole for the pitot mount in the skin and used the paper template provided with the mount to cut a hole in a scrap piece of aluminum, clecoed it to the skin, transferred the hole to the skin, and drilled additional pilot holes through the skin and mounting plate.

Feb - Apr 2022 (65 hours, total time to date: 3025.0 hours)

Got a little behind on the documentation of the work that I've been doing on the Midget over the last few months. I designed and fabricated inspection panels for the forward and aft wing skins. I decided to use rectangular panels with 0.75 inch radius corners in the forward skin inboard panels as well as the aft lower skin near the pitot as well as the 2nd and 4th wing bays. I fabricated a larger rectangular panel for access to the aileron bell crank. It had to be large enough to allow me to maintain the bell crank and push rod hardware. Then, I decided to use round panels in the forward lower skin in bays 4, 6, and 8. This arrangement will allow me to have sufficient access and visual inspection capability everywhere in the wing. I will also install a narrow panel on the aft top skin over the landing gear torque tube. This will allow me to remove the tube if it is ever needed. I will discuss this panel later when I am working on the aft top skin.

I finished fabricating the access panel doublers and covers required for the forward and aft bottom skin access panels. I drilled #40 pilot holes in the parts and match drilled them on the skins. As part of the fabrication process, I made master templates for each part and located the center holes for the round corners (and center of the round panel openings). I match drilled these on the skins and enlarged them to 0.25 to accommodate the pilot drill for the hole cutters. I began work installing the large access panels for the landing gear legs and the first bay in the forward skin. I did this first because I wanted to have the doublers riveted in place before I removed the upper skin to cut the round access holes in the skin using a 4 5/8 inch hole cutter on my work table. I also fabricated stiffener doublers for the landing gear covers (due to the size of these covers) and riveted them on the covers. I also fabricated small covers for the tie down fittings that attach to part of these stiffener doublers. I applied a light primer coat on the inside of the doublers before installation. Once the landing gear doublers and covers were riveted, I riveted the rectangular 4.5 x 5.5 inch access panel doubler in the first bay. This will permit access to attach brake line fittings and connect wiring from the fuselage. I decided to use #8 c/s machine screws for all of the covers, so I also dimpled these holes and installed nut plates in the doublers as required. Many builders use #6 fasteners, but I am concerned about stripping these small fasteners down the road.

May 2022 (30 hours, total time to date: 3055.0 hours)

I then placed each forward skin on my work table and clamped them to some scrap boards to protect the table and hold the thin skins in position to cut 3, 4 5/8 panel holes in bay 4, 6, and 8.

Finished work on the outboard forward win skin access panel doublers. I match drilled the double attachment holes to 1/8 inch (since the dimpling process opens up the holes slightly), drilled/reamed the cover attachment holes to 0.162, and dimpled the holes (#30 and #8), and added the #8 C/S nut plates. I used my pneumatic squeezer with the 1/8 inch dies to set all of the dimpled holes together (skin and doubler) to make sure that each hole was fully seated. I think this helps ensure that the rivets are set squarely. Cut, finished & dimpled the round covers. Finally, I riveted the doublers in place and temporarily attached the covers to the doublers.

Jun 2022 (25 hours, total time to date: 3080.0 hours)

Working on the access panels for the aft, lower wing skin. Also finished work in preparation to rivet the wing ribs to the main spar. I had drilled the holes out to 1/8, but was waiting to drill the final size to #30 until ready to rivet the ribs in place with universal head rivets. I drilled all of the holes out to #30 and de-burred all of the holes in the parts (ribs, spacers, & main spar flange). Dan Jansen came over to help me rivet everything in place. Very happy to get this accomplished.

Finished the aft lower wing skin access panels and riveted the doublers to the skins. Also, started work installing the master and starter solenoids on the firewall and cut 1 inch holes in the firewall for wiring pass throughs.

July 2022 (20 hours, total time to date: 3100.0 hours)

Dan Jansen came over again to help me rivet the leading edge skins to the ribs. We riveted the skins to the ribs on the top surface because I want to use solid rivets (which can be bucked from the back side before I close the bottom side). I then used my rivet squeezer to install the rivets in the upper root rib flange. I will leave the tip rib alone for now since I need to attach tabs to mount the wing tip fairings at a later date.

I started work closing the bottom leading edge skins using blind rivets where I can't reach the back side. I will use solid rivets along rib flanges I can reach through the access panels. I ordered more Cherry Max blind rivets and am waiting on them before I can finish.

Received the rivets and finished closing the forward wing skins.

Aug 2022 (30 hours, total time to date: 3130.0 hours)

I fabricated a set of drilling guides to help me drill the aft spar skin attachment holes in the rear spar flanges. Because of the differences in rib spacing (necessary for the ribs to be flush with the wing taper), it wasn't possible to use a constant 1 inch hole spacing along the aft spar. I wanted the hole spacing to look as uniform as possible, so I maintained an even spacing between each rib as far as possible. The spacing worked out to be between ~1.25 and 1.09 inches. After verifying that I could back drill through the inside of the rear spar and wing skin, I drilled #41 holes along the top and bottom of each rear spar flange. I also finished drilling #41 pilot holes along each aft rib at approximately 1.25 inch spacing.

Cut the two upper, aft wing skins out of one sheet of 0.025 4x8 2024-T3. I allowed for about 3 inches beyond the rear spar to be trimmed later. I started by using packing tape to attach the sheets to the forward skin with a slight overlap to allow me to back drill the existing pilot attachment holes along the main spar. Since the holes were uniform between each rib, it was easy to back drill using a 12 inch #41 bit. Once those holes were drilled, I removed the skins, and used a dremel cut-off wheel to trim the edge to form the seam line between the forward and aft skins. I trimmed the edge slightly long to allow for sanding to smooth the cut and make a nice, tight seam line.

I then replaced the skins to begin back drilling the #41 attachment holes through the holes previously drilled through aft ribs, again using a long drill bit. I worked my way down from the main spar. My wife helped be holding a 1x2 against the skin to hold it to the rib flanges as I drilled the pilot holes. I clecoed the skin in place as I progressed down the rib lines. Finally, I back drilled the skins through the rear spar flanges to finish locating the aft, top wing skin attachment holes. Finally, I cut and finished clearance openings in the top skins to permit the wing attach bolts to be installed.

Sep - Oct 2022 (20 hours, total time to date: 3150 hours)

Before I can trim the trailing edges of the aft wing skins, I need to be sure that I know exactly where to cut it. The biggest issue I see is the aileron hinge reinforcement that attaches to the rear spar web and the aileron hinge. In the Misc. Wing Details Dwg, the reinforcement is shown to be 0.032 thick and 44.312 inches long with a 35 degree bend (0.5 in flanges) at the spar and 63 degrees at the hinge. I cut and bent a shorter sample piece to check the fit. I quickly found that there are some complications that I hadn't considered.

First, the aileron assembly drawing indicates that the reinforcement flange is not attached at the intersection of the rear spar web and flange, but is offset slightly on the web. The problem with this is how it will line up with the existing fastener holes for the ribs. The second issue is how the 35 degree bend does not allow sufficient clearance with the rear spar flange (especially at the tip end of the spar). Another issue is related to the aileron control pass-thru doubler. The doubler fasteners must also be shared by the reinforcement. As a result, I am going to have to take more time to work through these issues. I have carefully traced the cross-section of each end of the aileron and rear spar area from the aileron assembly drawing (230.008). I need to decide how this reinforcement needs to be redesigned to work with my wing. I must say that it is very disappointing that I have found yet another example of significant issues with the MM1 plans and drawings. After lots of trial and error between the drawings and my wings, I came up with a geometry that works for both the aileron and flap reinforcements. Due to the changes I had to make to the aileron bell crank fitting (to make sure the aileron push rod clears the landing gear torque tube), I also had to be verify the exact location for the aileron push rod through the rear spar web. IN my case, the pass-thru needs to be just under 0.4 inches from the bottom of the spar flange instead of 0.313. I fabricated the two aileron reinforcements and am ready to start work on the flap parts. Once I knew where the aileron reinforcements would fit on the rear spar web, I finished work on the rear spar doubler for the aileron push rod pass-thru. I match drilled #40 holes for the left doubler, drilled a 0.625 pass-thru hole, and clecoed it in place. I also cut a piece of 4130 0.5x0.035 tube to begin making the aileron push rods. I will enlarge the pass thru after I am 100% sure I know the clearance requirements when connected to the aileron. I will wait to do the same on the right doubler since I currently have both aft skins on the right wing. Finally, I fabricated the aileron reinforcement pieces.

Nov 2022 (25 hours, total time to date: 3175.0 hours)

I began work on the aileron push rod for the left wing by drilling and riveting the rod end on one end of the tube and installed the rod on the bell crank. The pass-thru hole in the rear spar is intentionally small to allow me to check the alignment after I know exactly where the rod will connect at the aileron spar. Once I know exactly where it needs to go, I will enlarge the hole as needed.

I marked, cut, and bent the flap reinforcements. I drilled #40 pilot holes along the left reinforcement at 2 inch spacing between wing stations. Then, I placed the left flap reinforcement on the left rear spar, clamped it to the bottom, aft skin edge, and match-drilled (#40 pilot holes), and clecoed it to the rear spar web.

I fabricated the flap and aileron spars from 0.032 thick 2024-T3 sheet. I used a 6 foot length of 2x2 angle stock from Lowes as a straight edge to lay out the spars, and a dremmel cut off wheel to cut them out. I used a bending brake at Stewarts Aircraft Service near Waynesville, OH to bend the aileron and flap reinforcements as well as the spar flanges (I want to thank them for letting me use it).

Dec 2022 (20 hours, total time to date: 3195.0 hours)

I drilled #40 pilot attachment holes in the right flap reinforcement and match drilled it in place on the right rear spar. I then repeated the process for the right aileron reinforcement. As part of the process, I clecoed the skins to the ribs to be sure to have the correct spacing for the reinforcements given the attachment requirement for the control surface hinges. Once this was finished, I marked the final trim lines on all four skins (now that I finally know what is required to match the trailing edge of the reinforcements). Again, I found the drawings to be lacking in this area, but I understand that each builder will have slightly different dimensions. However, I think it's also important to let other builders know about these issues and I hope it will be helpful to remind them to be cautious. The last tasks I completed this month were to trim and finish these edges on the four skins and I removed the plastic on the outside of the skins around the attachment holes using a soldering iron with a polished tip and hung the skins on the main spar with 3/32 clecos.

Jan 2023 (24 hours, total time to date: 3219.0 hours)

Checking the rear spar/aileron reinforcement pass-thru hole clearance for the aileron control rods. I fabricated a 6 inch aileron spar/push rod bracket and attached a piece of hinge to look at the limits for the aileron and how the control rod will travel through the full range of motion. I wanted to get this done before preparing to rivet the aft wing skins in place.

https://youtube.com/shorts/g9HULfdS0TI?feature=share

I used a 1/2 inch sanding drum on my Dremmel to open up the aileron push rod pass-thru as required and cut the openings in the flap hinge reinforcement for access to the landing gear tube fitting bolts in the rear spar.

Feb 2023 (25 hours, total time to date: 3244.0 hours)

Riveted #10 nut plates on the landing gear tube fittings that attach to the rear spar.

I fabricated a drilling guide using a piece of 0.032 stainless steel to drill the 1 inch spaced hinge attachment holes for the ailerons and flaps.

I used the drilling guide to drill #40 pilot holes in the upper, aft wing skins for the aileron hinge. The aileron hinge is sandwiched between the skin and aileron hinge support. Once the pilot holes in the skin were drilled, I clecoed the skin and support and clamped the aileron hinge in place. Then, used the pilot holes as a guide to drill the pilot attachment holes through the aileron hinge and support.

I drilled the pilot holes for the flap hinges using a similar process. The difference is that the flap hinge is behind the aft, bottom skin and the flap support. I needed to cleco the skin and flap support in place to mark the trimming line for the skin to be sure that they are flush with each other. I trimmed/finished the parts, clecoed them back in place, and clamped the flap hinge in position. I was able to use the drilling guide directly on the assembly to drill the #40 pilot holes through the skin/support/hinge.

Mar 2023 (10 hours, total time to date: 3254.0 hours)

I opened up all of the flap/aileron hinge attachment holes to 1/8 inch. The skin and flap reinforcement holes will be dimpled, so I prefer to dimple them from 1/8 inch since the dimpling process enlarges the holes slightly. I'll open the hinge holes to #30 later for C/S. I also clecoed the aft, upper skins in place and drilled out the holes to 1/8 inch. I removed the skins and de-burred the holes. My plan is to get everything ready to rivet the aft, upper skins - this includes all of the prep work to rivet the rear spar in place since the rivets in the rear spar web near the upper skins are easier to reach with the upper skins removed.

I dimpled the hinge attach holes in the aileron reinforcement brackets.

Apr-Jun 2023 (10 hours, total time to date: 3264.0 hours)

It's been a while since I updated this BLOG, so I wanted to get caught up. I've been focusing on the Thorp T-18 since it's getting close to being ready to fly, and I've been flying the Smith (and running down more issues here and there).

Anyway, over the last 3 months I found some time to dimple the aft, upper wing skins as well as the ribs, main, and rear spar flanges in preparation for riveting these skins in place. I also C/S the hinge/reinforcement bracket attachment holes in the flap hinges.

Jul-Sep 2023 (20 hours, total time to date: 3284.0 hours)

I've been able to spend a little more time on the Midget lately, but not a lot since I've been test flying the Thorp T-18 and making some adjustments. I riveted the ribs to the aft spars in both wings as well as the flap reinforcement bracket. This needed to be done in preparation to rivet the aft, upper skins in place. The issue is access to the fastener holes in the rear spar that are close to the upper skins. When the skins are riveted in place, there is no room to rivet these holes. I did make one mistake that I wish I could take back - I didn't remember to dimple the holes in the rear spar flange above the flap reinforcement. The flap reinforcement blocks access to these fastener holes. So, I'll just have to use universal head blind rivets in these holes. Not the end of the world, but just a reminder for anyone else building the MM1.

Once I had everything ready to rivet the upper aft skins in place, my good friend, Dan Jansen came over to help me install the hundreds of rivets in these skins. We spent about 6 hours riveting the skins in place on Sep 30. Because of the changes I made to the aileron bell crank attachment to the 7th rib, there were three fastener holes that couldn't be bucked. These required Cherry Max blind rivets. Also, the rivet line along the upper aft spar flange can be squeezed with my pneumatic tool. I took care of those after Dan left.

Oct 2023 (20 hours, total time to date: 3304.0 hours)

Now that the upper side of both wings are riveted in place, it is time to prepare the lower aft skins. I riveted the aileron reinforcements to the rear spars. These need to be installed before the skins since there is no way to buck or squeeze these attachment rivets once the skin is riveted. The choice is install these with blind rivets, or use solid rivets to install them first. I think it is better to use solid rivets for the aileron reinforcements and blind rivets in the skin since the lower skin rivets won't see any significant tension and are out of sight on the bottom of the wings. The construction tips provide instruction to rivet these skins from the main spar working down and inboard by peeling the skins up from the bottom. This may look good on paper, but it's not so easy in practice IMO. I think there is a risk of creasing the thin skins and/or shifting the skins during the riveting process. I added several access panels in these skins, so they aren't as flexible as they would have been without the panel doublers. I'd rather have better access for maintenance and use blind rivets on the lower skin. Also, because of the access panels, there will be several fastener holes that can be bucked through the access panel openings. I'll use solid rivets where I can. Once the aileron reinforcements were riveted to the rear spars, I C/S the attachment holes in the aileron hinges that are sandwiched between the upper skin and the reinforcements. I then replaced the hinges and dimpled the holes in the skins into the hinge C/S. This worked well and ensures that the dimple is seated well in the hinge. There is ample opportunity for the skins to shift slightly during attachment and I decided not to dimple these holes in the skins until I had the skins riveted in place. Since the aileron hinge is sandwiched between the skin and reinforcement, only the skin holes needed to be dimpled. As a side note, I have read several posts about cutting C/S holes in 0.040 thick skins. This does not work because the dimple depth is > 0.040. In fact, the C/S in the hinge ends up as a knife edge situation to seat the dimpled skins. The hinge material is approx. 0.056, so I would never C/S an attachment hole for an 1/8 rivet in anything less than 0.062 unless there was no other choice. In this case, the number of rivets holding the aileron hinge results in relatively low loads overall. Beside the fact that the hinge stock is too thick to be dimpled. It is easy to dimple 0.040 material, but that is really the upper limit - again, IMO. After dimpling the skins for the aileron hinge, I riveted the aileron hinges in place.

The next task was drilling out the bottom aft skin attachment holes to 1/8 inch for dimpling. As I know I've written before, the dimpling process enlarges the holes, and I prefer to have less slop in the fastener holes and this seems to work out nicely. After drilling these holes out, I removed the skins and deburred the holes in the skins, ribs, and spar flanges. Then, I dimpled the holes in the skins, ribs, and spar flanges. I used my table dimpler for the skins and my pneumatic rivet squeezer to dimple the holes in the ribs and spar flanges.

Nov 2023 (12 hours, total time to date: 3316.0 hours)

This month I riveted the aft bottom skins to the left and right wings. This also included riveting the pitot tube mount to the main spar flange and skin on the left wing. I clecoed the skins in place and removed the access panels to allow me to buck solid AD426-4 rivets where I could reach and Cherry Max 3212-4 blind rivets everywhere else. Some attachment holes were accessible for my pneumatic squeezer (through access panel openings), so I used it where I could. Once each wing was closed, I clecoed the flap hinge in place and used my squeezer to dimple the attachment holes in the aft skin (through the dimpled flap reinforcement and C/S hole in the hinge. I decided not to rivet these holes until I fabricate the flaps and fit the flap spar to the hinge.

Dec 2023 - Jan 2024 (26 hours, total time to date: 3342.0 hours)

Now that the wings are closed, I decided that it would be easier to work on the flaps and ailerons if I took the wings off the jig and fabricated 2x4wooden stands so that the wings would be sitting nose down. I designed and built four stands to support the wings at the second and ninth nose ribs. I used 1-inch thick closed-cell foam inside the stands to protect the wings along the areas of contact with the stands.

The foam is easy to cut on the band saw, and I already had the nose profiles to transfer to the foam sheets from the 3/4 boards I used to help me form the nose skins around the ribs.

As I was preparing to remove the wings from the jigs and place them on the stands, I realized that I neglected to install wing walk supports in the left wing - oops! It didn't make sense to even try to remove the CherryMax locking blind rivets in the left bottom skin. They have to be ground out since the internal pins are stainless steel - too much work and the risk of damage is too high. So, I came up with a plan to cut out the first bay and leave enough material to rivet a replacement panel. I have learned that large access panels (like the ones I used for the landing gear) must be stiffened since continuity is lost in the skin. I needed to have enough room to work inside the left root panel, yet have a good plan for stiffening the lower skin when it was closed. I'll write more about that issue after I close that bay.

The plans call for 5, 0.75x0.75x0.0625 angles with 0.032 sheet below the upper skin to support walking on the wing to enter the cockpit. Since the ribs are all 0.025, it didn't make sense to use 0.032 doublers. That would create a gap at the second wing rib flange where there should be an attachment to the angle supports. In my T-18, there are no skin doublers between the 0.025 wing skin and the support angles (same angle dimensions), and the wing bays are wider than the Midget. So, I opted for 0.025 thick skin doublers to extend about an inch on either side of the angles and I added two additional 0.040 angle stiffeners in areas that I thought needed a little more support.

After thinking more about how I would be able to install (dimple & rivet) the wing walk supports, I decided that I would be able to do all of the work myself if I cut & finished the opening with the wing in the jig then remove the wing from the jig and set it on the stands. The center jig support prevents reaching around each side of the wing. I fabricated all of the parts, drilled #40 pilot holes, enlarged them to 1/8, dimpled the holes in the doublers, C/S the holes in the angles, and used my rivet gun with the dimpling attachment to dimple the holes in the upper wing skin. I have modified some tungsten bucking bars (drilled 3/16 holes) to accommodate dimpling dies. You need to be careful using this method in the thin skin (find the right pressure for the gun). The other issue was dimpling the holes through the skin and rib where I secured the angles to the second rib. On the root end, I bent 7/8 tabs in the 0.025 doublers to fit along the root rib and drilled rivet holes through the tabs and the the root rib. I think this is important because the angle supports work in simple bending where each end is simply supported (no bending moment). In this configuration, the maximum bending occurs in the "middle" of the angle and the shear is taken at each end. Without attachment to the ribs on each end, the shear is taken only by the 0.025 inch thick wing skin instead of being transferred into the rib web through the rivets. Since the root rib is canted, this is not ideal, but still much better than transferring the shear into the thin skin. I know it can be done (this is what exists in my T-18), but since I had the opportunity to do something better - why not?

Finally, I had to wait for our January thaw to be able to prime the wing walk support parts before I could rivet everything in place. In cases where I have 2024-T3 aluminum against more aluminum, I prefer to have some corrosion protection. The final product is shown below. Not perfect, but it will work. I need to do a little primer touch up to make it look better.

Feb - Mar 2024 (44 hours, total time to date: 3386.0 hours)

I continued working on the bottom left wing cover. I fabricated a doubler frame to attach to the bottom skin to secure the cover. Since it is a large cut-out, I also needed to add two stiffeners across the width of the cut-out that would also include nut plates for the cover. I drilled pilot holes to attach the frame and stiffeners to the bottom skin (and to the second rib flange for the cross stiffeners). I then started work on the 0.025 thick cover. I taped 3 sheets of paper together and taped it across the panel opening so I could rub the edges of the cut-out with a pencil to create a template for the cover. I carefully cut and trimmed the cover to fit nicely in place. I taped the cover in place and drilled #40 pilot holes for the nut plates to the frame and cross stiffeners. Then, I drilled the frame holes that attached to the skin and rib flange to 1/8 and dimpled them. I drilled the nut plate holes to #19 and used a nut plate drilling tool to drill the #40 holes for the 3/32 nut plate rivets. I dimpled the nut plate holes, applied a thin coat of primer to the parts, and riveted them in place.

The next step was to finish the cover by drilling the attachment holes to #19 and dimpling them for #8 machine screws.

The next step was to begin work on the ailerons and flaps. I cut the flap and aileron spars that I fabricated in Nov 2022 to their final lengths after carefully looking over the plans and measuring the hinge lines. I fabricated some test parts to check everything for proper clearances. I was especially worried about the push rods for the flaps since they run along the side of the fuselage and must fit over the top of the rear spar attachment. I made some cardboard templates to show the location of the fuselage and made a mock-up of the flap and push rod to be sure that everything would fit. Again, Murphy was an optimist. :-)

I took a slight detour because I remembered that I still needed to make attachment strips for fiberglass wing tips. There was no room to do this while the wings were in the jigs, but now I have access to each wing tip, so I should get this finished before doing more on the flaps and ailerons. The first task was to square off the tips evenly using my Dremel cut-off wheel and finishing the edges. I also realized that I needed to cut off the aft tip rib flanges to provided clearance for the aileron counter weights. Then, I needed to remove the flutes in the wing tip ribs that would interfere with the attachment strips. I decided to simply sand them down with my 1/2 inch Dremel sanding drum. This made sound strange, but the flutes were only needed to flatten the ribs before attaching the wing skins. Now that the skins are clecoed in place (I knew I had to add the attachment strips to these holes), the ribs aren't going anywhere. Sanding off the tip rib flutes leaves a "cut" in the rib flange between the rivets that are analogous to flange tabs, and the attachment strips will act as a doubler (although not needed at all). I made 4 attachment strips for each wing tip. I clamped each one in place, match drilled through the existing rivet holes. I dimpled the holes, scuffed the mating surfaces, applied a thin layer of T-88 epoxy, and riveted the strips in place on each wing tip. This leaves two layers of 0.025 material (skin and rib flange) for the fiberglass tips that can be 0.050 thick and flush with the wing skin. I will probably need to add flutes to the strips down the road, but I'll worry about that when the time comes.

Apr - Jun 2024 (50 hours, total time to date: 3436.0 hours)

I laid out the pilot hole pattern for the aileron and flap hinge and spar attachments. Instead of a nominal spacing of 2 inches, I decided to use 1.5 inches. This works out better for spacing since the attachments holes at each end are 0.75 where the corner gussets attach. I drilled #40 pilot holes through the hinges before clamping the spars in place to back drill. There is no margin for error as far as edge distance goes for the hinges, so I think it is a better idea to locate these holes accurately and back drill through the spar flanges. I used the stainless steel drilling guide I already had on hand with a 1-inch spacing. This allowed me to locate the holes 3 inches apart on the hinges with consistent edge distance. Once these were drilled, it was easy to locate the other holes with 0.75 and 1.5 inch spacing. I left the area about 6-8 inches on either side of the location of the aileron push rod fitting open to the hinge. I will wait to check the location and spacing of these attachment holes once I have fabricated and located these steel fittings.

I started working on the aileron push rod attachment fittings. Since the spar is tapered, I want to have a nice fit inside the spar. It took me a few tries to get this nesting correct. After finishing the aileron push rod attachment parts, I moved on to the steel inboard flap rib reinforcements and the flap control arm. The plans call for a round steel tube cut longitudinally where it is welded to the steel reinforcement. I decided to go with a 0.049 thick 5/8 square steel tube. It allows me to cut the attachment tabs to fit the rod end bearing perfectly. I also cut a square hole in the corner of the reinforcement and notched the square tubing so that the parts interlocked. This is much stronger, and allows me to give the parts to a welder (I'm not any good as a welder) and not worry about any mistakes during the welding process.

Next, I worked on the aileron counter weight assemblies. There were a couple of issues with the plans that I also decided to change for my airplane. The first was the double bend between the aileron spar and the counter weight. I think this is over complicated and blocks the last outboard rivet hole in the aileron spar. I decided to go with a single 93 degree bend in the fitting to extend the counter weight approximately 3/16 outside of the wing tip attachment flange. This will allow me to cut the clearance hole in the bottom of the fiberglass wing tips for the counter weights to pass through as the aileron deflects upward. In addition, instead of using a 1 inch, 0.049 thick round tube for the counter weight itself, I opted for a 1 inch square tube. It makes a lot more sense as far as fabrication is concerned and allows more surface area to weld to the bracket. It also allowed me to used 3/32 SS bling rivets to position the parts for welding. Finally, I took all of the parts to a welder friend of mine to be TIG welded. A picture of the welded parts (only one of the counter weight assemblies) is provided below.

I also fabricated airfoil profile boards to help set the proper alignment for the root flap ribs and tip aileron ribs. Now, I'm ready to drill the the rest of the pilot attachment holes for the steel parts to the flap and aileron spars.

Jul - Aug 2024 (24 hours, total time to date: 3460.0 hours)

I drilled #40 pilot attachment holes for the aileron counterweight brackets, aileron actuator bracket, and flap control bracket. I also installed a 2024-T3 0.025 aluminum doubler on the flap root rib. This is needed to reinforce the rib in the area that had to be cut for clearance with the welded steel flap actuator fitting. The doubler extends 0.75 in. aft of the end of the steel fitting so that two additional rivets may be installed aft of the fitting through only the doubler and the rib. This doubler fits on the inside of the fitting and rib and includes the flange area that attaches to the flap skin.

I then checked the alignment of the aileron and flap ribs before drilling #40 pilot attachment holes attaching the outboard flap and aileron ribs to the flap and aileron spars using the root and tip airfoil profile boards (see above). I fabricated a long ~110 inch 1/16, 2x2 aluminum angle by riveting 2, 5 ft long angles together using ~ 10 inches of angle stock as a doubler. I will use this to ensure the flap and ailerons are aligned in the neutral position by clamping this long angle to the trailing edges of the flap and aileron. Now, I'm ready to begin work on the flap and aileron skins.

Sep 2024 (10 hours, total time to date: 3470.0 hours)

I had a little delay because I needed to order a 4x12 sheet of 0.020 thick 2024-T3. While waiting for the aluminum, I used a piece of RAM board (cardboard) to make a template for the flap skins. I decided to fold the flap skins as the plans say the kit skins are fabricated (as if anyone can get kit parts from MA). Once the aluminum arrived, I used the template to rough cut the skins. I thought I could bend the 0.020 skins on my work bench clamped to a square steel tube. I quickly discovered that didn't work! Thankfully, I had plenty of material, so I cut another piece and went over to Stewarts Aircraft Service and borrowed their bending brake (thanks again to them). I started with the right flap skin laid on the ribs clamping each side (in turn) to the ribs to mark the locations for the flap stiffeners. I decided to line up the stiffeners with the wing ribs with additional stiffeners at the mid points. This works out to a little closer stiffener spacing, but I think it will look better and add a little more strength without a lot of additional weight. I also marked the top of the spar line on the flap skins that defines the stiffener length along the flap. Then, I began work making the stiffeners and laying them out on the inside of the flap skin.

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