Dave’s RV-7A Building Log

After reading everyone’s advice on the RV7and7A Yahoo Group, I decided to try resurrecting the small aileron push tubes. I first tried drilling out one of the rivets. Drilling out the manufactured head was easy, but it wasn’t enough to free the rivet. I also had to drill out the shop head. That was tricky, but not too bad. After drilling out both sides, I had a chunk of rivet still rattling around inside, I had to take the end off to get the junk out.

I drilled out all of the bad rivets, and then tried squeezing -11 rivets with the tube held in a vise. Worked like a charm. They still aren’t the most beautiful rivets around, but they will hold just fine. I cleaned the extra primer off the outside of the tubes with some MEK, and they look great.

I also dimpled around the edge of the right inboard bottom skin and started deburring the right outboard bottom skin.

Finished deburring the right inboard bottom skin.

I spent some time figuring out was is left on the wings. Eventhough it feels like I’m just about done, there’s still a fairly long list: finish flaps, finish push tubes, rivet bottom skins, mount ailerons and flaps, etc.

After that, I started working on the list. I pulled out the bottom skins. I clecoed on the left bottom skins and drilled out the holes for the flap brace. I’ll debur and dimple/countersink later. I put the snap bushings in the left wing for the pitot line. I’m going to use some plastic tubing for the pitot. I’ll run that later.

When I was last working on the right wing, I didn’t get around to deburring and dimpling the right bottom skins, so I started working on that. After finishing the ailerons this weekend, I don’t even mind doing something boring for a while.

The ailerons are done!!! I woke up before the family and had an itch to finish the aileron I started yesterday. I finished it off in an hour or so, still before anybody was up. I threw it onto the wing with just a couple of bolts to check it out. Too cool.

After breakfast I polished off the other aileron and temporarily mounted it as well.

There wasn’t anything too difficult about riveting the ailerons. I used the control surface break to hold the trailing edge nice and straight. Seemed to work great. Both ailerons look perfectly straight to me. Tightening the bolts on the smaller brackets was tough. I ended up putting a wrench on it sideways sort of jammed in there. That worked ok. I torqued all of the nuts to the correct value and sealed them with paint. One minor thing I did mess up, was that the third bolt on the larger bracket (the one that goes in the nut plate) apparently needed an -10L washer instead of a -10 like all of the other bolts. I thought about it for quite a while to decide if it would really make a difference, and then just decided to fix it.

Built the stand for riveting the flaps and got everything ready for riveting. Julie helped rivet the bottom of one flap.

Getting into the rear spar is tough. I ended up using the yoke from the squeezer, a tip I got from someone else’s site. It worked great. The plans don’t call out the rivets very well. I found that -3.5 rivets worked everywhere except where the two skins overlapped a rib. That needed a -4 rivet. On the end rib, I can’t figure out how to buck the rivet under the nut plate (arrow in pic). I read on someone’s site that they recommended attaching the nut plate after riveting the rib. Now I understand why. I’ll probably just use a blind rivet at that spot. I was able to buck all of the rivets where the rear spar intercepts a rib, except on the end rib (other arrow in pic). Again, the nut plate gets in the way. The plans call for a blind rivet there, so I’ll probably just do that.

Riveting the flaps is certainly not easy. It’s a tight squeeze for bucking, but it’s doable.

Clecoed one aileron together in preparation for finishing off the riveting. Set half of the remaining rivets on one aileron.

In addition to the aileron work, I primed the inside of the push tubes. I did this with some rattle can self-etching paint, it was kind of difficult to get good coverage all over inside.

I also tried riveting the ends of the bellcrank-to-aileron push tubes. I tried squeezing them. I tried using the C-frame with a hammer and with the rivet gun. Nothing worked very well. Out of 8 rivets, 2 of them set correctly. I’m now thinking about just getting new parts and getting them welded. Drilling out those rivets will be very difficult. The camera seems to be focusing on the background instead of the subject, but here’s one of the shop heads that sheared off.

Pulling the blind rivets on the stick-to-bellcrank push tubes was much easier, although it was difficult to get the holes aligned again especially with primer making it a very tight fit. Those push tubes turned out great. I still need to prime the outsides, but that will take just a few minutes with the rattle can.

I also pulled the conduit into the left wing.

Another big day. Julie helped me rivet the top and bottom skins of the ailerons to the top of the spar. From this point, I think I can do the rest solo. It looks like the remaining riveting is blind or squeezable.

I screwed the aileron spar to a 2×4 on each end and clamped that to the workbench and rolling tool cart. It worked out great. We each had great access for riveting and bucking. I’m not sure why some people have trouble with this step. I found it to be pretty easy.

Super productive evening. I started off cleaning up the push tubes to get them ready for priming. But then Julie announced she was ready to rivet. She helped me get the tough rivets on the aileron brackets done. Then we riveted the flap braces to the rear spars. That could probably be done solo, but it’s much easier with two people. I then squeezed the rivets on the aileron gap seals. The wings are really starting to look done. Just one more big hurdle left–the bottom skins.

I finished up the prep on the stick-to-bellcrank push rods by marking and drilling the holes for the rivets. I started with a #40 drill in the drill press and hand drilled them to #30 on the bench. I removed the ends and deburred everything. They’re ready for primer.

Looking for something else to do, I worked on the bellcrank bushings. First I used the Scotch-brite wheel to clean up the ends and shorten the bushings a tiny bit. The plans call for them to be 1/64 to 1/32″ longer than the bellcrank, and mine were 1/16″ longer. I also reamed out the middle to 1/4″ with a reamer I bought a few months back. I put the bushing in the vise, dipped the reamer in cutting oil, and went for it. No sweat.

After months of debating on whether to use conduit in the wings for wiring or just use snap bushings, I finally decided to use the conduit. I think it’s overkill, but I already bought it and everybody else is using it. The entire length of the wing is accessible from the access panels, so I still think the snap bushings would have worked. However, looking in AC 43.13 (which I recently bought), the wires should be supported with a clamp every 2′. That sounds like more hassle than the conduit.

I installed the conduit in the right wing. It’s a hassle to pull it through, especially with 3/4″ holes, but it works.

I’m darn near done with the prep work on these wings. After a few more hours, I’ll have nothing but riveting left to do. I’m hoping that Julie is willing to do some riveting this weekend.

By the way, if you don’t have AC 43.13 “Acceptable Methods”, buy it. It’s only $20. There is a ton of useful info and charts in there. Do you want to know how many wires you can put in a conduit? It’s in there. Do you want to know what the marks on the bolt head are for? In there, too. And a whole lot more.