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How do avionics affect emp/wing/fuse exclusions/inclusion?

gotyoke

Well Known Member
Imagine you won a sweepstakes for a particular avionics package (any) BEFORE ordering any of the other kits. Such a windfall might affect what you would include/exclude from those kits, right? The first things that come to my mind are wiring and mounting brackets. Perhaps ADAHRS, pitot tube, and things like that. What else?

Here is why I am asking: I have this notion that I'm going to build and wire my emp and wings. Then, three years later I will select my avionics and guess what, now I have to remove and re-run a bunch of wires. Is this a legitimate concern, or am I just not understanding how this will end up working out?
 
Imagine you won a sweepstakes for a particular avionics package (any) BEFORE ordering any of the other kits. Such a windfall might affect what you would include/exclude from those kits, right? The first things that come to my mind are wiring and mounting brackets. Perhaps ADAHRS, pitot tube, and things like that. What else?

Here is why I am asking: I have this notion that I'm going to build and wire my emp and wings. Then, three years later I will select my avionics and guess what, now I have to remove and re-run a bunch of wires. Is this a legitimate concern, or am I just not understanding how this will end up working out?

I was able to run all my required wiring in QB wings with only the bottom outboard skin off. I ran a few strings through the bushing incase I wanted to add anything later on. I believe you could do everything through the inspection holes if you had to although it would be more challenging.
 
Wiring diagram

Before I moved my project to a hangar, I had a somewhat heated garage here in the great white north. I used winter for doing things in the basement, like deburring or administrative work as I could on the airplane. One winter I decided to read (2x) the aero electric connection and draw a wiring diagram. Wishing I would have done that much sooner, like the 1st year. I had a lot of “I’ll figure that out later” items early on in the build that are a lot tougher to access now.

A long winded way of saying get yourself a wiring diagram. You’ll need it eventually. I actually did 2, one for circuits to power whatever, and a separate one that is all how the avionics connect to each other. It might help answer your questions. That said, I’m working on an -8, maybe other airframes are different.

Good luck,
Sam
 
You are over thinking the problem.

The number and size of wiring for most the avionics vendors are about the same.

You can run a 3/4” conduit that you can get from Van’s by enlarging a tool hole in the ribs to accommodate the larger hole size. You can do something similar running in the side walls back to behind the baggage bullhead.

Just plan a few minutes planning with your first couple avionics vendor choices to understand where you are going to locate all the pieces. You’ll start to see that there is more in common than is different.

For example, adahrs in the empennage or perhaps the wings? How many wires of each guage need to be run? Do you need to run the pitot, static, and AOA tubing to them?

If you plan correctly during your build how you are going to get wiring from point a to point b, ensure the route has appropriate capacity, you should be fine. If you are using conduit, look up the capacity limits as to not cause overheating. The FAA publishes a great reference manual that all builders should have. Also ensure that you always have a pull string in the conduit, even when you’re done. You never know if you’ll need to pull another wire.

In my RV-10, I have a conduit in each wing, and three conduits in each sidewall going back to the empennage. I ran my power cables in separate conduits than the data cables.
 
You are over thinking the problem.

The number and size of wiring for most the avionics vendors are about the same.

+1.

On all my builds wire runs come at the end. Some thoughts:
- For the wings I find a single 1/2” cold water pipe from Lowes is large enough for all wing wiring (pitot heat, nav/strobes, Landing/taxi lights, autopilot servo, wingtip NAV antenna, etc.). If you built to plans the hole you drilled in the ribs are the right size for this pipe. For the left wing Pitot/AOA runs I add a separate 1/4” snap bushing for one of the tubes.
- Consider not purchasing the Van’s wiring kit as I find it does not meet my needs. For example I prefer three #20 conductor shielded wire for Nav/Strobes.
- On the RV-14 I found the tail wiring kit (with the plethora of molex connectors) to be more trouble than it is worth. Here simple wire runs are a good approach.
- Decisions to make now however include things like two axis electric trim, mounting a second ship battery, any change from the Van’s wing ADHARS mount and such. One decision to do before closing out the bottom of the left wing is what Pitot you will use. The must do part is the Pitot mast install (many can use the same mast). Nice to do is the Pitot Heat controller mount (if you end up with a pitot that has this - like the Dynon heated Pitot/AOA).
- Autopilot servo mounts are nice to do ahead of time, but can be done later.

Carl
 
+2 on Bob & Carl's very good suggestions.

Start building the Emp kit, & while doing that, do some research into what your lighting & avionics dream equipment might need for wiring runs.

My favorite conduit material is the light weight black plastic irrigation tubing in 1/2 & 5/8" sizes. Smooth & slippery inside to slide wires in later & plenty big enough to run any wiring needs you talk yourself into adding down the line.
 
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Imagine you won a sweepstakes for a particular avionics package (any) BEFORE ordering any of the other kits. Such a windfall might affect what you would include/exclude from those kits, right?

If I won it, I would not exclude anything. Might be able to either use stuff, or sell it.
 
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