Dave’s RV-7A Building Log

Riveted the reinforcement angles to the arm rests. They feel very solid now.

Deburred the holes on the left forward side skin.

Back from nearly a week off. We went to Sun Peaks in B.C. for some skiing. Actually, I learned to snowboard while Julie and Adele skied. We had a great time, but it’s a long drive up and back–6 hours of driving. It’s a little over an hour in an RV, 200 nm. I also just figured out that Aero Sport Power is located at Kamloops Airport. We drove right by there. I could have stopped in for a tour. Darn.

To break back into the project after the trip, I did a little deburring on the left forward side skin.

Picked up some more GBP-988 primer and finished priming the batch of fuselage parts I started on Saturday. I added the arm rest parts to the batch as well. The rattle can primer is sure easy. And it’s awesome to be able to prime outdoors in 55 degree weather in January. This has been the warmest winter in Seattle that I can remember.

I worked a bit on one of the side skins. I fixed the bend near the corner rib. I didn’t make the bend quite tight enough at the forward end. I think it’s good enough now. I did a final pass on deburring the edges and tried to debur all of the holes.

The stupid Ni-Cad batteries in the cordless screwdriver seem to be developing a memory as they are running shorter and shorter over time. The screwdriver came with a flashlight, which I rarely use. The batteries are the same between them, so I tried swapping batteries. That didn’t help much. Maybe I’m just getting more tolerant of deburring and am able to do longer sessions at a time. I never used to run the battery down. Either way I’m going to have to buy another one.

Since I couldn’t do any more deburring, I switched to something else. I remember reading a suggestion by someone to reinforce the arm rests. Jack Lockamy reminded me of this tip this week. Apparently, it’s very tempting to put all of ones weight on the arm rests when hefting ones self in and out of the cockpit. That could make the arm rest buckle. I’m sure I could train myself not to do that, but guests could be unpredictable. It may not ever be a problem, but it’s easy to add some 3/4″ angle under the arm rests at this point to completely rule out the problem. I cut back one leg of the angle 1/8″ so it’s completely hidden under the arm rest. I thought about trying to round the corner of the angle so it would nest nicely inside the bend of the arm rest, but it would be too much work to do that for really no structural or aesthetic gain. I used the rivet fan to evenly space out 10 rivets along the angle. They ended up being a few inches apart. I drilled out the angle, then backdrilled one angle to the other and then backdrilled each angle to its respective arm rest. After some deburring, countersinking, and dimpling, they were done. It ended up being a couple hour diversion that was pretty fun.

The cordless screwdriver recharged enough to debur the rest of the right side skin. I followed that up with dimpling around all of the edges. I had to carefully study the plans and mark on the skin which holes don’t get dimpled. It’s basically the holes for the seat rib, around the wing spar, and the gear weldment. That side skin just needs some dimpling on the C-frame.

The weather was supposed to cooperate for priming outside, so I etched a huge batch of parts that I previously washed including the longerons

It continued to drizzle on and off throughout the day, so it was obvious that outdoor painting was not going to work. I cleared out an area in the garage for painting.

Once I had everything set up, I went to mix the primer. Apparently, I forgot that I needed to order more of the Aircraft Finishing Systems primer. I ended up resorting to the Sherwin Williams GBP-988 rattle can stuff. I didn’t even have enough of that stuff, so I made sure I got the longerons painted since they are a hassle to deal with. I managed to prime one side of everything and both sides of some parts. I’ll pick up more paint on Monday and finish it off. Even with the garage door wide open, a tiny bit of the paint fumes found their way into the house. That’s why I much prefer to paint outside.

I continued with the experiment of filling in a countersink with JB Weld epoxy. I sanded the epoxy down until it was flush with the surface and re-drilled the hole through the middle. I countersunk some .040 sheet and riveted to my experiment. It seemed to work out well. Just to be sure, I drilled out the rivet head and separated the two parts. The epoxy held up well. The picture shows the drilled out rivet still in the holes.

I went on to fill in my accidental countersinks in the stiffeners. I also dimpled around the edges of the forward bottom skin.

Deburred the rest of the aft fuselage along the longerons and dimpled as well. The list of things is getting shorter and of course I’ve left the most monotonous tasks to the end. I pulled out the bottom forward skin and deburred all of the holes.

I bought some JB Weld to fix the extra countersinks in the floor stiffeners. It’s basically just epoxy that should be sandable. To test it out, I drilled and countersunk a chunk of scrap aluminum and then filled it in with JB Weld. We’ll see how it holds up to riveting after it sets up.

I removed the front half of the F-704 from the center section and did some trial fitting of the gear mounts. Eventhough I dimpled the F-704 already, there is plenty of room for shop heads under the gear mount. I’m not worried about that anymore.

I deburred the F-704 and F-705 bulkheads and started deburring the rest of the aft fuselage where the longerons attach. I also dimpled the F-705 and drilled holes for the static line. Yeah, I said holes, plural. I’ve gotten so accustomed to drilling holes on both sides for the rudder cables, that I drilled holes on both sides for the static line. No harm done. Maybe they’ll come in handy for wiring or something.

The list of items remaining to prep before assembly is getting shorter. I mainly just need to debur and dimple the side and bottom skins and then prime everything.

Finished deburring the outer seat ribs, drilled and attached nut plates, and tapped them out per the plans and instructions.

I finished up deburring and dimpling the firewall. I moved on to the aft fuselage section, prepping the F-706 bulkhead and then the skins. I removed the corner ribs and trimmed a little off of the aft end so it would clear the flange of the F-706. I also deburred the corner ribs. I removed the outer seat ribs and started deburring them.

I realized that I was over-zealous in my counter-sinking over the weekend. The ends of the forward floor stiffeners that overlap the F-704 flange should be left alone, but I countersunk them. On the plans, it says to countersink the skin where those stiffeners overlap the flange, and I had forgotten that I already did that. If I can’t figure out a way to fill in the countersinks with epoxy, I guess I’ll have to order new parts. Not a big deal, but annoying.

What I should have done while disassembling the fuselage was to mark where countersinks are needed on each part one by one. I just took everything apart, and then it’s hard to visualize what goes where and what needs dimpling or countersinking.