Chicken or egg or cart or horse

Steve · #1 01-24-2007, 07:04 AM

I working on my -9A panel with steam gages / day vfr / slider canopy. What order or events worked for you guys? Build panel on the bench or in the plane? Top skin before of after panel install? Or some combination of the two?

Thanks to all,
Steve

pierre smith · #2 01-24-2007, 07:10 AM

Hi Steve,
Don't put the top forward skin on until just before the first flight

Seriously, you absolutely need the access and wire up the panel/airplane and radios way before you install the skin. It's a royal pain lying on your back over that spar hump

.
One suggestion is to strongly consider having a dedicated, removable panel for the flight instruments (for access later) and another for the avionics. We didn't do this and now I wish that I had.

Some rivets will be inaccessible to buck and you can use flush pop-rivets in those holes and fill them later when you bondo the forward lower lip of the windshield.

Regards,

DeltaRomeo · #3 01-24-2007, 07:14 AM

Dan C. made access panels in his top skin, Steve.

Dan Checkoway photograph

Many more pics at: http://www.rvproject.com/20031124.html

b,
dr

videobobk · #4 01-24-2007, 07:28 AM

I'm with Pierre all the way--put on the top skin only when you have to. Also, the "modular" idea is great. I cut out a hole the size of the six pack and made a subpanel slightly larger held on with 10 screws. I can pull the six pack in about 10 minutes and have good access to most of the wiring. Removing my engine monitor gives another hole for access to the other side. Doug's pic of the top access is something to think about, too. Wish I'd done that. Either of these ideas should allow you to do most of your wiring directly in the panel instead of on a bench.

Bob Kelly

FrankK90989 · #5 01-24-2007, 08:07 AM

I riveted the skin on early, built & wired the panel on the bench. Worked good for me.

bsacks05 · #6 01-24-2007, 08:18 AM

I installed my top skin before the panel because I wanted to get the windscreen finished. Yeah, it is a pain connecting wires while lying on your back. I used lots of pillows so it wasn't too bad. Keep in mind that if you install the top skin last you will still need to be on your back to buck rivets with all the wires in the way. Of course, access panels and modular panels can make that easier. If I were to do it again, I would do the same but I would do as much wiring as possible on the bench and I would make sure that my wire runs are accurately measured and bundled to eliminate the rats nest of spaghetti I ended up with. I would also be sure to install other things such as fuse and ground blocks, data acquisition units, encoders, etc.. while the top skin is off.

prkaye · #7 01-24-2007, 08:22 AM

Quote:

flight instruments (for access later) and another for the avionics

What is the difference between "flight isntruments" and "avionics"? This is not meant as a criticism of what you wrote, I'm just not sure what the term "avionics" correctly refers to (I usually use it synonymously with "flight instruments").

bsacks05 · #8 01-24-2007, 08:47 AM

Avionics - The branch of technology which deals with the design, production, installation, use, and servicing of electronic equipment mounted in aircraft.
Ref. Dictionary of Aeronautical Terms - 2nd. Ed.

Flight instrument examples are altimeter, airspeed indicator, rate of climb, etc. They are often refered to as "steam gauges" in their round form.

prkaye · #9 01-24-2007, 08:52 AM

ah, so Avionics is all the electrical stuff (including electrically powered gyro instruments). Airspeed and altimeter are not typically electrical (except in glass panels) and so are excluded from "avionics".

gorbak · #10 01-24-2007, 09:01 AM

We wired the panel on the bench, placed this in the plane, ran all the wires and hooked them up at the terminal ends. This allowed us to get really nice tight wraps and streatched straight runs before we even thought of riviting the top skin. With three of us working on this panel project, we had gone over this a dozen times or so. We did volt checks, visual checks, electrical checks and then hooked up the battery to do checks on the radios, transponder, guages....the works. We found two wires reversed at the oil sensor (low oil warning) and corrected.
Then we got all excited, but checked one more time to see if there was anything visual that we needed to do. We then riveted on the top skin and went to work installing the front windshield and glassed it all in. This weekend, while working on placing the servo to the auto pilot in the wing, I asked my partner "where are the wires for the fuel tank floats?"

We went back to the fuselage to find that we had wired the two fuel guages to the buss bar but had not run terminal wires to each wing root. AAARRRGG

Now we get to experience the contortionist position to add the two wires (one to each guage) and squeeze these into the already wrapped and straight wire runs to each wing. We now understand the true feeling to the Southwest Airlines commercial tag line "Do you want to get away?"

Three people, six eyeballs, detailed drawings and we looked at this for a month and we still missed two lengths of wire. Sheesh. We went back to the detailed drawings and sure enough, the two wires had *not* been highlighted in yellow as completed. Fun, fun.

Pat Garboden
Ozark, MO
Todd Wiechman
Building in Wichita, KS
RV9-A 942WG (reserved) O-235 w/ slider, Catto two blade FP
RV9-A 942PT (reserved) O-320 w/tip-up, Sensenich FP