Sunday, May 17, 2009

Playing with the panel

Yeah, I know, most folks would have the panel done by now. What's it been? A couple of months? You know, the lawn was looking at me funny. The deck still needs some work, the fence needed painting. The garage needed cleaning. And I was born with the ability to feel guilt.

Out at the hangar, the grill needs to come home and the bench -- the one I sit on and think deep thoughts during the summer -- needed sanding and staining. So that was my plan today. One piece of non-airplane work and then one piece of airplane work. I don't know why I feel like I need to "earn" the time I work on the airplane. But I do.

I finished up the instrument panel cutout for the ICOM A-210 the other day. So today I put it the PS Engineering intercom. Originally I was going to put this on the other side of the rib. But, you know? There's a good chunk of room underneath the transponder. Now, someday I may want to put a full audio panel there. So I can just cut it out. But for today, perfect.

Then I needed to figure out where to cut the subpanel to allow the radio tray to come through. I fired up my dad's old Dremel tool and, voila!

I'm not exactly sure what needs to happen on the forward side of the subpanel. I assume some angle needs to strengthen it and be used to screw down the tray. The holes for the screws in the tray, though, are pretty far -- farther than 3/4 angle -- forward of the subpanel. And should I reinforce angle on the bottom and top?

Meanwhile, my building friend, Brad, stopped in to check Tom Berge's recommendation that the wires from the strobe/nav light in the tail come through the center of the vertical stabliler. The more we thought about it, though, the more we decided since we've already gone through on the side (without cutting through the vertical stabilizer spar, we best leave it there.

Then he mentioned he had a power supply and a harness for the Dynon 100. So I borrowed it to be sure that when the Dynon went black when I was playing with it a few weeks ago, it was because the backup battery was dead. It was.

I played with it for awhile. It's pretty cool and will be just fine for me, the VFR pilot. I did find its altimeter to be more accurate than the Falcon gauge I bought from Van's as a backup altimeter. I set it for the field barometer and elevation and the Falcon gauge is off by about 80 feet. Not good. No instructions came with it so I don't know if there's a way to calibrate it or what.

Anyway, I left it on for a couple of hours and removed the power supply and, nope, the Dynon didn't come back to life. I don't know how long the battery needs to be charged but it's not doing its job right now.

I've got to get me one of these power units, though.

So the only holes left to make in the panel -- at least until I win the lottery -- or for switches. Master, start, flaps, electronic ignition. I haven't figured out what I need for that yet, though. All in good time. One of the good things about spending a pile of money, is it gives you time to work on stuff without spending any more.

1 comment:

  1. Hi Bob,

    While that's definitely a fancy power supply there are plenty of other options that would be more affordable and still power the EFIS adequately. According to the Dynon specs any power supply from 10-30 DC volts will work fine. The specs call for 12 watt draw (24 if charging the battery) which makes me think from that picture the internal battery isn't being charged at the time of the picture. 0.83 amps @ 12.6v is about 10.5 watts (amps = watts/volts)

    There's a ready supply of power supplies in that range most commonly used by amateur radio operators to power radios (I have several I use for that purpose) that aren't terribly expensive. One option would be this supply from Radio Shack which the Minneapolis store, according to their site, carries. That's a good bang/buck ratio on a supply - and with actually 12x the current capacity you need, but 13.8v bench supplies can be very useful. Another choice could be the RS-4A from Astron. It's a 3 amp (1.5x capacity you need) supply but would likely be fanless (the radio shack will have a fan) and Astron's are made in the US. The Astron has a "cigarette lighter" plug so you would need an adapter for that. The Radio Shack has screw terminals on the back.

    To get a cable, the specs claim it's a DB-25 which is a plug you can commonly get at Radio Shack. To avoid soldering, the "crimp-type d-sub connector" is your best choice. The unit has a male connector, and I don't have any female connectors at the house to get a part number - but it's male "equivalent" is 276-1429 and they should be able to find one for you from that. 20 gauge or larger wire should handle the current draw of the Dynon as long as you keep the cable short (10ft or so, though twice as long should still be safe) 20ga should also just barely fit inside the crimp connections of the mentioned connector. (22ga is used by the Dynon harness but the harness is only 3ft long...I'd go bigger for a longer cable)

    So how to connect it? See page 3-3 in the installation manual and I think I've found why the draw was so low - and why your battery didn't charge. "primary power" (pin #1 on the DB25 cable) supplies operational power. "keep alive power" (pin #2) keeps the internal clock running and "draws just enough current to keep the clock running and keep the optional battery charged". Pin 3 is the master ground. So: wire from pin 1 runs to positive on your power supply, wire from pin 2 also runs to positive on power supply, and wire from pin three runs to negative on power supply.

    Adam Fast
    KC0YLK (general class amateur radio operator) and private pilot, all-around geek.