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Old 01-24-2017, 10:31 PM
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KatieB KatieB is offline
Join Date: Jun 2010
Location: Belton, MO
Posts: 1,145
Default Avionics Shelf

The top nose skin of the RV-3 was designed to be removable to access the fuselage fuel tank, but this is an RV-3B, so my fuel tanks are in the wings. It has a tip-over canopy, which isn’t sexy like a slider…at all…but it affords the opportunity to attach the front top skin to the fuselage with screws. This is an AMAZING maintenance item! I will never have to stand on my head to work on my avionics. And, hopefully, the way I install the avionics tray and wiring will allow me to remove it if I have to dive in to service the rudder pedals, brakes, battery box, or fuel system.

Tony originally used this shelf system to mount his Dynon stuff, fuse block, manifold pressure sensor, and other little things. His shelf is too narrow for the Garmin LRUs I need, so I made a new one. Posterboard was my best friend here. I made a posterboard shelf, complete with folded-down flanges for a little “strength,” and then I cut out paper versions of my LRUs so I could play with layouts. I thought for a while that I would need to install the ADAHRS and transponder in the baggage compartment, but after some playing with the cardboard, I fit everything in the nose.

[IMG]0114171517a by jabiruchick, on Flickr[/IMG]

The ADAHRS was designed to be mounted to the back of the EFIS screen, but some experts advise against this now. The ADAHRS requires an extremely rigid mounting surface, and the panel boxes of some planes have proven to be too flexible for it. Additionally, it’s handy sometimes to remove the EFIS screen to access the avionics bay, but if the ADAHRS is hanging onto it, you have to disconnect the pitot, static and AOA lines. So, I wanted to mount it on the side of the baggage compartment instead, but the more I looked at potential designs for a mounting bracket, the more I started to like the back of the EFIS screen. The RV-3’s panel is a small semi-circle supported around the top by the .032 top skin, and my panel face is built of .062 with a piece of ¾” angle riveted to the bottom edge. I feel confident that it’s the stiffest place on the plane short of the wing spar. My husband has an aerobatic Panther with the same setup and no ADAHRS issues so far.

I didn’t have enough .032 or .040 laying around the shop for my shelf, so my RV buddy Possum brought me an old pre-punched .032 nose skin that came out of an RV-7 kit. He had already cut off one side of it for a custom part for his “insane” but beautiful Zenith 701 project. After shearing and bending it on our 3-in-1 bending brake, I thought it was still a little jello-ish so I back riveted a stiffener to it. I was able to re-use 3 holes that were already drilled into the longerons to mount the shelf, so that was nice. One hole even had a random 3/32” hole next to it which fit the nutplate perfectly. Back riveting worked fairly well for the LRU mounting nutplates, too. After prettying it up with some paint and attaching all the LRUs, I felt like I had really accomplished something-- which is something I haven’t felt about this plane in ages!

[IMG]0119171652 by jabiruchick, on Flickr[/IMG]

[IMG]0120171514 by jabiruchick, on Flickr[/IMG]

[IMG]0123171846b by jabiruchick, on Flickr[/IMG]
Katie Bosman
EAA Homebuilt Aircraft Council
Rebuilt most of SNF tornado victim RV-3B Tony Boy II (had to sell him, but he's flying!)
VAF Dues Paid 2021!
Thoughts & opinions expressed here are my own, and not those of my employer.

Last edited by KatieB : 01-24-2017 at 10:34 PM.
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