Matt's RV-7 Project

I can't afford a real two-inch standby attitude gyro (they cost a mint… and I'm talking this kind of mint, not this one) so I have a TruTrak ADI instead. It's not a real attitude indicator, but it should be good enough for a backup instrument. And since it's a safety-of-flight item, I wanted to make sure it was fed by dual power paths, as are the other most important avionics in my panel. Unfortunately TruTrak didn't provide dual diode-isolated power inputs like Garmin did, so I had to use a pair of 1N4001s to create my own:

Heatshrink tubing protects against shorts – after I took this photo I added another piece, then crammed the whole assembly into the D-sub backshell. One side is fed by Bus 2, which powers my important avionics, and the other side is fed by the standby battery. This arrangement will also keep the gyro alive while cranking the engine, which might be a good thing considering some of the funny behavior Matthew reported when he had his ADI powered on while starting.

Here it is mounted in the panel… I verified that it powers on, figures out which way is up, and receives GPS data.

Port-side view of the ADI wiring harness. The D-sub connector comes pretty close to the panel, but there's enough room to avoid kinking any wires. However, it would not have fit if I'd mounted it in the center standby instrument hole as I'd planned, which is why I moved it to the top.

"But I thought the ADI wouldn't fit in the top hole!" you say, or at least that's what you might say if I allowed comments on this blog, which thanks to the efforts of spammers I don't, thank you very much spammers. "You even posted a photo of this exact thing!" you might also exclaim if I let you. Well, yes, but that was before I figured out that a UMA light bezel inserted ahead of the instrument spaces it back far enough to clear the panel frame:

So thanks to the light bezel the ADI now lives at the top of the stack of standby instruments.

This is actually great news, because I was already planning to use UMA light bezels for my standby altimeter and airspeed indicator, and I was bothered by the fact that the ADI's internal lighting didn't match them in color or intensity. So, I broke out my Fluke and did some probing around… It turns out that I was able to defeat the ADI's internal lighting by connecting the 5V output pin on the dimmer unit to the ADI pin that's designed to be connected to a 24V lighting bus. What happens is that when I turn on the nav light switch, thus energizing the dimmer, the ADI sees five volts on its 24V lighting input (equivalent to 2.5V with a 12V lighting bus) and reduces the brightness of its orange LED display… but 5V isn't high enough to turn on its internal lighting, so I'm free to use my light bezel to light the instrument face instead. The dimmer potentiometers don't care about the extra milliamp or two that the ADI sinks on its lighting input pin. Excellent.

If you're still awake after reading the above paragraph… yes, I can be a huge geek sometimes.

We had a few people over to our house this weekend, so I decided to clean up the garage and install everything in the airplane cockpit that I could get my hands on. It turned out to be a nice conversation starter.

This was the first time I'd seen the full interior installed at the same time the panel was all powered up. Looks nice.

There are a few things visible in these photos that I haven't documented on the site yet, but I'll get to them soon.

Of course a lot of what you see here is still yet to be finished, but it was neat to see so many things looking "done" at once. One might even think, looking at these pictures, that it might someday become "actually done".

The following is a guest post…

Mary here, talking to all of you who ladies whose husbands have said, "Honey, I want to build a plane in our garage."  You're understandably freaked out right now – I was when I found out that building airplanes is one of Matt's favorite hobbies.  Don't fret!  This is a doable project!  However, you shouldn't go into it blindly.  Here are some things to expect from an airplane-building husband.

This is a huge endeavor. OK, you probably already figured that out.  But let me give you a little perspective.  Matt began building the plane in Spring 2005.   I started pharmacy school the following fall.  I graduated this month, but Matt's plane is still a year away from flying.  This is not for the flighty (no pun intended).  This is like having a baby.   The plane will be a major part of your lives for years, if not the rest of your life.  (Thankfully, there are no 3 AM feedings.)  And much like a baby, a plane will require you to invest a good deal of money and space.  Consider:

1. You'll need workshop space.  For a lot of you, this means you'll have to give up parking in your garage.  You also might find an airplane canopy on your guest bed, or ailerons in your spare room.
2. It gets expensive.  Builders need rivets, rivet guns, clecos, pliers, drills, screws, an air compressor, wires, deburring tools, wrenches, countersinks, fiberglass material, hoses…  It adds up, and will continue to add up throughout the project, as he'll need to get more and more stuff. The UPS guy and I are pals.
3. As I mentioned above, it takes a ton of time.  If you want to be at his side 24/7 either be prepared for him to never finish the plane or go out and help him. Which brings me to my next point…

Building an airplane is not just something for him to do.  This can be a family project. You don't have to be out there every second – despite what the pictures on Matt's blog might suggest, I'm not out in the garage every time he is.  It will go a lot smoother if you get involved.  There are certain tasks that are a lot easier to do with a second pair of hands, and everything that gets done puts you a little bit closer to flying.  Even going to the workshop for a few minutes to look at the neat new thing he built can be a big morale boost.  And men, this is a two-way street.  Make a deal that for every, say, 30 minutes, your wife spends on the plane, you spend that much time on something she likes, or do some of the household chores for her, or stay home with the kids while she runs errands.  And speaking of kids, they can help too.  But use your good judgment; letting your toddler handle a rivet gun is probably a bad idea.

You'll meet a lot of new people in this process. Your husband will probably make friends with other builders through VAF, the EAA, and local airports.  Take advantage of this! For one thing, it gives him someone else to talk shop with when you get sick of the airplane stuff.   For another, a lot of these guys are married too, and you and the builder's wives can commiserate.  Airplane people are some of the nicest, most interesting people you'll ever meet.  Far-flung airplane pals can also tip you off to places to visit on your next vacation and maybe even get you a free lunch somewhere.  (Thanks Doug!)

You need to be his #1 cheerleader. I'm not asking you to put on a short skirt and wave pom-poms [aww. -ed.] unless you enjoy that sort of thing, [woohoo! -ed.] but airplane building can be a frustrating process, and your husband probably won't enjoy every part of it.  (See also: Matt and fiberglass)  Help keep him going during the difficult parts.  If you can't help, come down and talk to him while he builds, or let him bounce ideas off of you.

You may also need to keep him on task. Again, not every part of this is enjoyable, and it's easy to get discouraged, especially for someone who has a demanding job.  He may, like Matt, suddenly think it's more important to work on one of his other projects than the plane.  While sometimes that's necessary (the plane can wait if Junior needs help with his science project), too much of that can mean he loses momentum and before he knows it, he hasn't worked on the plane in a month.  Planes that don't get worked on don't get done, and we want these planes to get done.  I once had to threaten Matt with no slushes for the rest of his life if he didn't give up his extra projects and just focus on getting the plane done.

And finally, have a sense of humor. So your friends all think you're crazy, you can't walk into your house without tripping over a just-delivered box of parts, and your guest room looks like an obstacle course.  So what?  You and your spouse have a fun (hopefully) relationship-strengthening project you can do together, and even if you're only minimally involved, you always know what he's up to.

Congratulations to Mary on earning her doctorate!

She's been working a whole heck of a lot harder on her education than I have been on my airplane. That may have something to do with the reason why she got done first, and she definitely earned it.

And yes, the girl in the background does have a giant pill on her head.

Well… I am just now getting over whatever it was I was sick with for the last week-plus. I missed four days of work last week and I didn't touch the airplane at all until today. And all I did today was string a few more wires, so that's not very interesting.

We also found out this week that Mary did in fact land the postdoc residency she wanted – it's close enough that she'll be able to commute from home, which means we won't have to worry about moving for another year or so. Still, I need to hurry and get this thing finished before the clock runs out!