Dave’s RV-7A Building Log

Adele and I had a sleep over at the Pacific Science Center last night, so no progress on the plane.

The top angle on the seats nests inside the curve at the top of the seat back, so the outer corner of the angle needed to be rounded off. In the past I’ve used various power tools to do this, but I think the easiest method is just using a Vixen file. It took a while to get the radius looking good on both pieces.

I also cut the tabs from the middle of the bottom hinges.

Messed around with the seat backs some more. There’s no order specified in the directions or plans for building these things. I decided to start by drilling holes in the vertical angles. I carefully laid out the holes on one of the angles and drilled them on the drill press using a fence so the depths would all be the same. Be careful to note that one of the holes (the one for the hinge) has a different depth than the others. After drilling one angle, I used that to transfer the hole locations onto the other 3 angles.

The next step was to back-drill the angles to the seat backs. The plans say the seat backs should be 26 3/8″ long, and to trim if necessary. Well, mine are 1/4″ short. I guess the flutes are a little too aggressive. I figured out that flattening the seat backs makes them slightly longer. I put one seat back between two pieces of plywood and stacked a bunch of heavy stuff on top. After leaving it overnight, hopefully it will stretch out a bit.

I moved on to working on the seat back braces. I laid out the holes on the hinges and drilled them. I then carefully located the hinges on the braces and back-drilled them.

That was it for tonight. These seat backs are definitely taking longer than I thought they would. I thought I’d crank them out in one night, but nothing on these things is prepunched. Makes you realize how much time the pre-punching saves.

Worked more on the seat backs. I cut the lightening holes and trimmed the ends of the braces. I also cut the hinges to length and deburred them. The hinge dimensions on the plans are a little misleading. It looks to me like the hinge at the bottom of the seat is 16″ and the one that connects the seat brace is 15.5″. That’s how I cut them anyway. We’ll see how it works out.

While waiting for some help on riveting the fuselage, I’m moving on to work on the seat backs. I want to be able to sit in this thing once I turn it over! I fabricated the 8 angles needed for the seat backs.

There were several chunks of angle to cut, and they wouldn’t fit in the band saw. I dragged out a special metal cutting wheel I bought a while back for the chop saw. I didn’t work very well on aluminum at all. It tends to melt the aluminum instead of cutting it. I tried a really fined toothed blade in my Skilsaw instead. That ended up working really well.