Matt's RV-7 Project

Right after our Thanksgiving trip we went on a second trip, and as soon as I got back I managed to contract some kind of deadly pandemic, so between sickness and travel I haven't been able to work on the airplane in a month. Today I was finally feeling up to spending some time in the cold garage, during which I managed to rivet the subpanel structure in place.

I riveted on all the things that attach to the center subpanel rib, then installed the outboard subpanel ribs. I found you have to do it in that order, or else there's no way to get the rivet gun in where you need it to go. You can also see in this photo that I've riveted the radio tray mounting brackets to the subpanel.

You're supposed to put washers between the F-7108A center rib and the F-7108B angle, in order to make a slot for the rollbar brace to fit in. I thought the idea of using rivets here was kind of hokey, so I drilled the holes out to #12 and used bolts instead. The rollbar is temporarily installed for this step in order to make sure everything lines up right.

The rivets at the lower outboard corners of the subpanel were a giant pain to put in. I had flashbacks to F-705, which was only slightly worse. I used various single- and double-offset rivet sets on these. Some of the factory heads are a little dinged up, but they're otherwise just fine. I had to remove the fuel vent lines to be able to get in there, which was also annoying.

I was unable to finish the two bottom-most rivets that attach each of the outboard subpanel ribs to the firewall, since I don't have the right rivet set to get in behind the engine mount. I'll pick one up with the inevitable next Avery order, and finish these guys off when I have a chance.

Just another photo of the same stuff. It's good to be able to work on the plane again.

I decided I didn't want to have to loosen a billion screws and take up an entire floor panel just to service the aux battery I mounted under the baggage floor, so I measured out a small cover plate that will make access a little easier.

I cut out the corners with a hole saw:

Then with snips and files I finished cutting out the hole in the floor. Here it is being test-fitted… I can get the aux battery in and out through here with no problems.

I made a cover plate out of some scrap 0.032" and match-drilled and dimpled it to fit the existing screw holes. It's plenty strong, and now I have less than a dozen screws to undo to get at the aux battery.

The cover plate isn't flush with the floor, but since this area will have carpet over it you'll never know the difference. I did use my edge roller on the plate before I dimpled it, which helps it sit down nicely against the floor.

I ordered my fuel valve with built-in banjo fittings, with the idea that they would make it easier to route the fuel plumbing within the confines of the selector valve enclosure. Sure enough, it was very helpful to be able to make small adjustments to the angle of of the input lines. After I got everything lined up, I tightened the banjo fittings and safety-wired them in place. Banjo fittings will only pass fuel when the silver nut thing is rotated to a certain orientation relative to the flare fitting, so you don't want them to move around on their own.

Since the edges of the fuel pump mounting plate will be slightly visible where the carpet meets the spar, I decided to paint it to match the rest of the interior. This of course involved removing all the components, which I was going to do anyway. I also put a fresh coat of paint on the selector valve mounting plate, since it was a little bit dinged up. While the paint was drying, I blew out all the fuel lines and inspected the flares for FOD. Finally, I put everything back together and tightened each and every fitting.

I put a dab of torque seal on each fitting to remind myself that I did in fact tighten them, and also to be able to look for loose fittings during annual inspections.

I made a little cover for the selector valve shaft out of some dowel scrap, to keep it from poking me in the ribs when I'm crawling around inside the fuselage. I elected not to put the selector handle on just yet, since it's equally rib-pokey.

I ran the long fuel line that goes from the outlet of the pump up to the firewall:

I used a steel fitting through the firewall, since a flexible hose will connect to it on the forward side. I've decided to use only steel fittings on anything that carries important fluids and will see substantial vibration.

What a mess. The electric pump plumbing is insane-looking but it all fits. I did have to remake the line on the port side that feeds fuel into the selector valve, in order to clear some other plumbing. One other thing to note is that it's going to be very tricky to get wires routed between all this stuff and through the pre-drilled wiring holes in the spar (just barely visible behind the spaghetti).

Here's a view of the other side. Everything fits together, amazingly enough.

A view looking aft. None of this is permanently put together yet – I'm planning to take it all apart and blow the crud out of the lines before I tighten it all down for good.

Me doing science in the airplane laboratory: