Matt's RV-7 Project

When I was up refreshing my night currency in the rental 172 a few weeks ago, I noticed that Cessna put a little light bulb above the fuel selector valve so you can see it at night. I found this to be a nice touch, and thought it might be neat to put something like that in my airplane too.

I bought a blue LED from the local Radio Shack, and hooked it up to a bench power supply (along with a suitable dropping resistor) to see how bright it is. Yeah, that's probably plenty bright:

I soldered a 1k resistor to one of the leads, which will run the LED at about half brightness. Then I shrink-wrapped the resistor and leads:

I bought a couple different diameters of thin-wall aluminum tubing at the local hardware emporium, and made this little spotlight hood for the LED. The flange at the base of the LED is squared up against the end of the smaller tube, and it's all potted together with JB Weld.

I played with a lot of different mounting locations, and eventually settled on this spot at the forward end of the throttle quadrant. I made a little mounting plate out scrap alclad, painted everything black, and mounted the spotlight with an adel clamp. Although it's tight in there, the throttle cable has plenty of clearance from the lamp.

Here's a wider view. The end of the lamp is not visible to the pilot or passenger, so there won't be any glare.

Hey, how cool is this? I love doing these little custom touches.

Some time ago I bought an expensive SIRS whiskey compass, and preparing for its installation has been on my to-do list for quite some time. Since I'm still on flu recovery detail, I figured this would be an easy enough project. First I had to go find the rollbar, brace, and forward top skin:

I marked a location on the rollbar brace that puts the bottom of the compass about a half-inch above the glareshield, to allow room to install a nice-looking trim piece later on.

I marked a centerline on the rollbar brace using a handy piece of angle, and drilled two rivet holes using a V-block. I won't actually rivet the compass mount to the brace until I first send it off to be powder coated.

I tested the internal lighting with a bench power supply… yep, it works.

Then I ran wires from the panel light dimmer to a spot just below where the compass will mount, and put a plug on it. Didn't remember to take a picture of this, but you can imagine what it looks like. The compass is now back in its box, and will likely be one of the last pieces of instrumentation to be permanently installed.

I have this idea that I'll install a small map light on either side of the cockpit… I haven't figured out exactly where I'll put the dimmer knobs, or even the lights themselves, but that hasn't stopped me from buying a pair of LED lights and dimmer modules. One of the latter is shown here:

I mounted a dimmer to the F-721A canopy deck on either side of the cockpit, which seemed like an okay location.

I removed the included attachment feet and made some mounting brackets out of scrap alclad. The odd shape is required to clear the traces on the board, and the nutplates are there to allow me to remove the thing later on if it goes blooey.

Just to see if it would all work, I hooked up one of the dimmers to one of the map lights and a bench power supply…

Well, it all works. Eventually I'll find a place to put these.

You might recall I was displeased with the way the audio panel wiring was impinged upon by the crosswise brace at the top of the radio stack. This weekend, I fixed that particular glitch by drilling out the rivets in the piece of angle across the top of the cutout in the subpanel, and very carefully enlarging the cutout by another half-inch. At various times I was going after the subpanel with a unibit, a cutoff wheel in a dremel, various files, and a scotchbrite wheel in a die grinder… luckily I managed to avoid nicking any of the hundred or so wires back there.

New reinforcement pieces were cobbled together out of various pieces of scrap I had laying around. Since I was working around a bunch of existing structure that couldn't be moved, it was kind of a puzzle figuring out the best way to get everything attached securely together.

Here's what the finished product looks like from the aft side. Compared to the previous version, the new brace is substantially higher. There is a 0.032" spacer between the angle and the subpanel, which is bent around underneath to form a kind of cable guide.

A little piece of scrap angle ties the new horizontal brace to the existing vertical piece. It's kind of cheesy, but it's plenty strong. There's plenty of room now for cables and connectors to pass through. You can also see that I had to use another screw and nut in the inboard hole, since there was no way to get a squeezer in there and I didn't want to risk smashing something delicate with the rivet gun.

I also changed the desiccant material in the engine dehydrator plugs again… the dark blue one is filled with fresh silica, and the other one is old. Later on I baked the old silica until it was the same color and the new stuff, and dumped it back into the container.