Wing Wiring Conduit

I am starting work on a set of RV-9 wings I bought as a partially completed project. I plan to use CPVC pipe with riveted hangers through one of the lightening holes in the ribs. I will leave a gap in the conduit where wires need to exit for landing lights, etc. My question is which of the four big holes should I use, and should the conduit be run along the top, bottom front or rear of the hole? I suspect there is an optimal location to avoid interference with the aileron push tube and a good exit location at the wing root for wire routing.

You really dont need a conduit. Every rib is accessible from the access holes in the bottom of the wing, or through the wing tip. It?s a one time deal, you run these wires once and then never use the conduit again.... Secondly, if you have a conduit, you need a way to get wires out of the conduit, mid span for pitot heat wires and/or leading edge lights. (Not every wire goes to the wing tip). I installed a conduit in my -9A but wont bother next time. It was more hassle than it was worth. Maybe just secure a couple adel clamps or zip ties to each rib to secure the wires.

I used to own a -9A and had to add several wires into the existing wings for an autopilot. It was a hassle, especially at the wing root. The tips were riveted on. I was planning to leave gaps in the conduit where the wires would break out mid-wing. If I use conduit, I think I could rivet the tips on rather than screw them on with nutplates. Any advice where to run the wires or conduit?

We changed autopilot servos when we installed the G3X. Since the wings were already on the plane, it was a hassle pullling the new wires and urging them through the existing grommeted holes.

Another option(s) is is to put in large service loops so wires can be reused (make sure they?re labeled); and/or run a few spare wires for futures. My plane had neither. If you?re contemplating AOA, run a plastic line for that too.

The other MAJOR hassle is running wires from the wing root to the panel. When you build your fuselage, do the same planning ahead you?re doing now. If it were me, I?d consider putting connectors in the wing root in case you ever need to pul a wing. Service loops are good here, too, if the wires are labeled so you can splice them back after wing removal.

Good news is a little planning now can save lotsa hassles later.

I plan to use service loops and a termination block in the wing root to allow more panel wiring to be done before the wings are installed. Searching through some old threads, it appears the best place to locate a conduit is through the second largest lightening hole near the top. This should avoid any interference with pushrods and bellcranks. I will leave gaps in the conduit to allow for wire exits part way out the wing.

Just my 2 cents but I put conduit in my 9 wings when I built them originally. I am building a 10 now and am not putting conduit in. I'm simply using snap bushings as recommended by Vans. I do plan on putting a pull string through when I run my wiring just in case I even need to pull some new wires. That said, as Dbro says..all ribs are accessible so it might take another 5 minutes but I could easily run another wire or 5 down my wings through the bushings.

If you are set on running conduit, don't run it down the larger holes...you will need those to get your arms into the various bays.

Ahhh... Good point about not blocking the large holes. I will rethink my plan. Thanks.

If you have the standard size holes in the wing ribs that Van?s calls for (to install the nylon snap bushings), the holes are the perfect size for 1/2? plastic water pipe from the aviation department at Lowes.

For the left wing the pipe runs to the bay where the pitot is mounted, then a few inches of gap, then another pipe to the wing tip. For the right wing the same way except gap is at the bell crank for autopilot servo.

The pipe is big enough for all the wires and one pitot line. If you have an AOA add the second line where Van?s tells you to install the 1/4? grommets.

Carl

Carl, the holes provided are about .430 dia. and I need about .650 for my CPVC pipe. However, I can easily open them up with the wing open. I will also need to make new holes from the bellcrank bay outwards, as none are provided. I plan to add an AoA system. Thanks for the advice.

Have you read the document that Van's posted about wire in wings? I put the link below. I just added the holes on the bottom of the rib where indicated and run their corrugated stuff all the way through.

https://www.vansaircraft.com/pdf/Wing_Wiring.pdf

I saw it and that is what I am going to do. Thanks.

I used the Van?s corregated tubing per their directions in my QB wing. Major pain to drill and deburr some of the holes, but it is a rock solid clean installation. Glad I took the time to do it. Good luck.