time for conduit - Part 2

[Lorin Dueck]

Hi all -
I'm also at the point where I need to run conduit thru my wings. Top skins are riveted on.

I'm building a 9A, bought the corrogated conduit from Van's, and drilled 3/4" holes in my ribs prior to assembly at their recommended location.
I have a Tru Track A/P with a Servo in the right wing and Duckworks landing/taxi lights in the LE of both wings. I plan to use Whelen strobes - and possibly LED nav lights.

So here are my questions.
I'm not looking for a definative answer - just what others have done and how well it worked for you....
1. How did you run the conduit, what lines did you put in them, and did you have other (separately located) lines to prevent electrical interference?
1.a. Since the LE lights are not at the end of the wing - did you cut the conduit and leave a gap between two ribs in the section with the landing/taxio lights, find a "Tee" section that could be used, or something else?
2. Since the A/P may be susceptible to EM interference from the high voltage strobes - where did you run their A/P lines? What did you use to secure the wiring to the ribs??

HELP!! I'm stuck.. and would like any suggestions / recommendations...

Thanks a bunch.

Lorin D
RV-9A (Wings)

[TomC]

Hi Lorin,

This is what I did. Its been a couple of years but I know quite well since I just installed an autopilot this summer. I first have a wiring run in each wing for the strobes. I wanted them separate from anything else. Secondly, there is a run in each wing for the landing lights, nav lights, pitot heat, oat probe, etc. I also ran my nav antenna RG-400 with this bundle as I have a wingtip antenna. When I added the autopilot, I made a separate, third run for it as the second set of bushings was too full to add anything. The runs are 2-3" apart. I have not experienced any interference. As far as the landing lights, I ran the wires all the way into the wingtips and then backtracked the foot or so to the landing lights.

The only thing I would change on my system is that I did not line up the wing holes with a set of holes in the fuselage. Since there is only about a 3/4" gap between the wing and the fuselage, it was very interesting getting the wires from the fuselage into the wing holes (can you just hear the nice words? ).

I hope this helps and good luck.

[svanarts]

1. How did you run the conduit, what lines did you put in them, and did you have other (separately located) lines to prevent electrical interference?
1.a. Since the LE lights are not at the end of the wing - did you cut the conduit and leave a gap between two ribs in the section with the landing/taxio lights, find a "Tee" section that could be used, or something else?

I used Van's corrugated tubing. I basically just enlarged the holes that he calls for the wiring grommets to be in. I enlarged them just enough for the tubing to go through (with some effort). I took the tubing all the way to the end of my wing. I then ran all wires through the conduit. Wires for the landing lights came out the end of the wing and then went back in through a grommet in the outboard rib to the bay where the landing light is located.

2. Since the A/P may be susceptible to EM interference from the high voltage strobes - where did you run their A/P lines? What did you use to secure the wiring to the ribs??

My strobe power packs are mounted to the outboard rib. Only 12VDC wires are running through the wing. I did this specifically to get the power packs as far from my radio wiring as possible. I don't have an autopilot so I never worried about that.

[cnpeters]

Chapter 16 of the AeroElectric Connection states that shielding doesn't guarantee blockage of magnetic coupling to other wires and consideration of separating the strobe run from the other wires may be helpful. But, since the wires are to the various lights and servo, I'm not sure there will really be any problem to even run them all together. I'm not sure on the antenna. In forum discussions, others have had no problem even with a fuse mount power supply. It is very important to properly ground the shield at the source/power supply, and assuming your strobe is mounted in the plastic wingtip, to ground the strobe housing to the shield. Both Bob Nuckolls and particularly Greg Richter recommend running ground wires with your equipment to a central ground bus instead of just counting on frame grounding to further decrease the chance of noise.
For your other wires, I can't find anything that states they can't be run together. Any real world scenarios and anecdotes out there with singular bundled wiring??