Dave’s RV-7A Building Log

Spent more time deburring the aileron structure and skins. For being so small, the ailerons sure have a lot of edges and holes to deburr.

Julie offered to schedule a riveting “date.” If she isn’t at work too late, maybe we’ll get something done on the wing skins tomorrow. I think it helped when a neighbor stopped by Sunday and was asking about all the rivets taped into the wing skin. “What are these for?” “Oh, I’m just waiting for some help with riveting.” I was almost afraid he was going to volunteer. I wouldn’t be excited about training a new riveter on the top wing skins.

Last night we were at the Mariners game. The M’s are not doing well this year. They were down 4-1 in the 8th and we were tired, so we headed home. Wouldn’t you know they pulled out 3 runs in the 8th and 9th and then a grand slam in the 11th. Oh well.

Finished drilling the first aileron. Clecoed together and drilled the second aileron to final size. Drilling the galvanized pipe takes quite a while and makes a mess of iron shavings. Drilling the hole that holds the little tab to the galvanized pipe is tricky. The instructions say to go through one of the holes on the spar with a long drill bit. It works!

I just noticed something interesting. On Dan’s aileron drilling page at the bottom, you’ll notice that the tabs on the aileron nose ribs point inward. Apparently, Van’s changed this since the tabs now face outward. I guess this was done to make drilling and pulling those blind rivets easier.

I also started deburring all of the parts.

Working on the ailerons is pretty fun. It reminds me of working on the empennage. After a few dozen hours, you have a complete part versus the hundreds of hours that the wings take.

Clecoed one aileron together and after carefully checking the rivet call-outs, drilled most of the holes to final size.

Worked on drilling the aileron spar reinforcement plates and brackets. After weeks and weeks of mind-numbing wing work, this was kind of tricky. There are three different size holes in each end, so you have to be awake. I deburred everything after that.

The right fuel tank is leak free. The level bounced up and down 3-4″ with the change in temperature of 70 to 77 degrees, but stayed right in the range of the warmest and coolest mark I made on the first day. Yeehoo!!

With the one problem rivet duct taped, the left tank is holding air. That’s good news. The water level in the manometer was down this morning, but went up past last night’s level once it warmed up today.

I set up the right tank for an overnight test. Fingers are crossed.

Time to test the fuel tanks. Since the plastic tube is still hooked up to the left tank, I decided to test that one first. This tank had the one leaky rivet near the fuel filler that I tried to fix. I set up the tank, and sure enough the level started going down very gradually. I used the soap bubbles to find out that it was leaking around the fuel cap and unfortunately around that same darn rivet. Bummer. The worst thing about that leaky rivet is that I can’t make sure the rest of the tank has no leaks. But then an idea hit me. I put some duct tape over the problem rivet, put more fuel lube around the fuel cap, and pumped it up again. We’ll see if everything except that stupid rivet is holding air.

Back-riveted the stiffeners onto the second aileron skin. Used the control surface bender from the empennage to close up the ailerons. I got the skins to bend within an inch of the spar, but couldn’t get them to bend any more. It looks close enough. The radius of the bend is right in the range specified by the instructions, 3/32″ to 1/8″.

The next step is to back-drill the spar to the reinforcement plates. But it’s not super clear what hole should be drilled to what size. There are 1/8″ rivets, 3/32″ rivets, and bolts on each end. I spent about an hour studying the drawing and the instructions figuring out how all the parts go together. I decided to wait until tomorrow before drilling. I want to look at everything again when I’m not so tired.

Finishing up the wing is waiting for some riveting assistance, so I went back to working on the ailerons. I dimpled the stiffeners holes on both skins and back-riveted the stiffeners onto one of them.

Julie helped me square up the wing again. It was square when I drillled, but I’ve bumped the wing a few times since then and also had to move the jack once. We iterated several times between checking the spar sag, wing wash, and square-ness of the wing structure. It’s all within 1/32″ all around and the skin holes are lining up great.

Clecoed the right leading edge skin to spar holes and clecoed on the inboard top skin. I generally put a cleco in every 2nd or 3rd hole. Adele helped me put rivets in the other holes and cover them with Scotch tape. That way when Julie has time to help, the riveting will go faster. We’ll still shoot every rivet going down the ribs, but we’ll only have to stop every 3rd hole to put in a rivet. The Scotch tape serves three purposes. First, it holds in the rivets. If we started riveting on there without it, all of the rivets would pop right out. Secondly, it keeps the rivet set from marring the skin. Not a big deal as it will all get painted eventually. And thirdly, it helps keep the rivet set from sliding around. This is not as much of a concern on a flat surface (versus the front of the leadge edge, for example), but it still helps.