Tuesday, December 16, 2008

Panic attacks

I picked up a bunch of avionics goodies down at SteinAir on Saturday... and I haven't had a good night's sleep since. I've woken up each morning with some sort of "what have I done?" panic attack that a lot of RV airplane builders know well. I had the same feeling back when the fuselage kit was delivered and I took everything out to inventory it. I thought, "there's no way I can do this, there's too many parts." But, some years later, there the airplane sits on its landing gear in a hangar at South St. Paul airport.

I deeply hope the same thing happens here because -- it can now be revealed -- I haven't got a clue what I'm doing here and there aren't that many parts! I've generally come to understand AeroElectric Connection after years of reading it, and I've sketched out a wiring plan of sorts, but this? This is the real thing. There are wires that go from here to there, split to yonder, loop past somewhere, and end up plugged into some other gizmo which, if you do it right, will light up and work. And if you do it wrong, will cost you thousands of dollars.

That's what's waking me up at night. I have no idea where to start, what to do, or what to plug in where.

What you see up above there is the Garmin 327 transponder (which as near as I can tell doesn't come with a harness or any instructions for installation, but I could be wrong), the Dynon 100, which comes with a harness I bought ($90), although I'm not sure what goes where (it does come with a nice installation manual, however.)

There are a few labels at some ends of the wire, but not at the other. (Update: Stein tells me"
The first harness is the Dynon harness as well as the Transponder harness. The connector with the metal cover on it is for the Txpdr. We wired the Txpdr and Dynon together for you to try and simplify things in the future.)

And also above is the Vertical Power 50, which is a nifty little unit that will make my wiring simpler,I'm told. But when I wake up at night, this isn't very simple to me:

I think this is the premade $295 wiring harness, although as you can see, it's not entirely premade. VP, according to the installation manual, requires a special crimping tool for its D-SUB connectors, which -- from what I understand -- are made from the gold plating of Saddam Hussein palaces. You need to buy a special tool ($300) to crimp them or rent one at $10 a month (with a deposit). I was under the impression you didn't have to do that if you bought the wiring harness, but I hadn't finished the load planning worksheet for the plane yet so I don't think Vertical Power had any information on what equipment I'd need to wire. My fault. I think.

I'm sure this is going to be fun. It's the sort of project that just begs for a weekend-long blizzard in Minnesota to force me to tackle.

But first I have to head off to work, where perhaps I can get a good day's sleep.

(BTW, check out Tom Velvick's blog. He has a VP-100 installed and his post on the start-up sequence is really interesting.)


  1. In what I am sure is an odd mix of naivety and masochism, the wiring and avionics install is the part that most appeals to me.

    That is said, of course, from the outside looking in. I thought long and hard about re-doing Papa's panel, but the cost/benefit simply didn't work out in my favor. Maybe some day I will build a -12. It's more attractive now that I can start with the relatively cheap tail kit. Still, the CFO maintains a unilateral and all-powerful veto.

  2. Bob, yes the electrical system was very intimidating, almost overwhelming before I actually started. I was advised to take it one wire at a time and that really did help. After a while I got into it and enjoyed it. Also a big help was to pick a wiring schematic and pretty much stick to it. I used the Bob Knuckolls Z-11 diagram. Or you could use Vans drawing. I started by wiring up the power and ground buses first, then the avionics. Following the Z-11 diagram gave me confidence, and I came to really understand it.

    I have the Garmin 327 transponder also. It was actually the simplest of all the boxes to hook up. Just a power wire, ground wire, and then a wire that feeds the Dynon. I bought mine from Stark and it came with the little 3-wire harness.

    ... Bill Cloughley