Thanks, Brett!


I started off today by getting the second door stripped of fiberglass, Lexan and its latch bracket. Since I learned yesterday that a #28 drill does a nice job separating the head of a 1/8" rivet, that process went a lot faster. Removing the latch bracket was quicker as well, since I didn't bother with the grinder and went straight for a propane torch. Heating the bracket for about 20 seconds boiled the powder coat under it and it knocked off easily. Another two 1/4" holes and a couple of minutes' shaking got the rivet stems out, so I just need to strip the powder coat and they'll be ready for welding.

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Next on the agenda was getting the small parts of the control column mounting block out of the paint stripper and cleaning them up. When I dry fit the parts together I discovered that the spacer and mounting flange were different shapes, which wasn't going to satisfy my pilot brain, so I took them to the belt sander and with them clecoed together, sanded them to match one another. Some surface sanding and Scotch-Brite buffing got them ready for Alumiprep and Alodine (along with the hinge plates from the second door), then I pulled my first rivets and was rewarded with a rehabilitated assembly, ready for installation!

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Next up was getting the rudder torque tube assemblies riveted together. I ducked into town for a pot of bearing grease, smeared a modest amount on the inside and outside of the four PVC bearings, slid the tubes together and riveted them in place. Having no experience with such things, I was impressed with the smoothness added by the greased bearings; it's a noticeable difference from the dry parts. I just wonder how many years the grease will last before I'm drilling out 24 rivets to reapply.

I figured I might as well finish prepping the rudder tubes for installation, so I started work on the four outer bearings. Two of the originals were ruined in disassembly, so I had two fresh ones from Kitfox and was anticipating a lot of sanding to get a good fit. They must be smaller diameter than the originals, because they were a perfect fit right out of the box. I had to run a 1/4" drill through the bore to get the AN4 bolts through, and I shortened them slightly so I'd have a couple of threads outside the nut. The two usable old bearings were still too big, so I sanded their ODs for a smooth fit as well, and ended up with the whole mess ready to go into the fuselage.

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The final task for today revealed a bit of a problem. I removed the pin retaining straps from the control mixer, extracted the pins and pulled the assembly apart. The reason it was so stiff became immediately obvious: the -416L washers had been embedded in powder coat and the whole thing seemed to have been assembled without lubrication.

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I used the Scotch-Brite wheel to remove powder coat from the mating surfaces and to clean the pins (I'll use new ones for final assembly), then tried a dry-fit to check for better movement. I had a very difficult time getting it back together, as even with the powder coat removed there's only room for a washer at one end. I was only able to get the second washer installed my really gritting my teeth, and once together it didn't move much easier than it had in the first place.

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As you can see from the second photo, I need about half a light washer thickness, plus a few thou for grease. Is this lack of space a common problem in the control mixer? Are builders removing a few thou of steel from each of the four mating surfaces to make room?

Finally, a couple of questions about rudder pedals:

1. The flanges on all four of mine are not bent to a 90° angle, so the bolt and nut have to pull the flanges inward when they're tightened, creating drag on the pedal's rotation. Should I compress them in a vise to achieve a full 90° bend before assembly, or is this normal and acceptable?

2. The plastic bearings that run through the "tee" at the top of the pedal tube are very tight on the long AN3 bolt. I have to apply a lot of pressure to get the bolt to go through, so it doesn't rotate after assembly; the bearing isn't functioning as a bearing. Do I need to run a #12 (0.189") drill through them to open them up a tad, then apply grease?