System Holes in Wing Ribs
 

I began drilling the systems holes in my left wing ribs tonight and realized that I should make sure that I have enough room for the systems my plane will have. I am not doing anything that hasn't been done before, so probably someone has already sorted this out.

Here's the inventory of what needs to go through the wings:
* Standard wiring harness
* 2 wires in left wing (pitot heat ground, taxi light)
* 1 wire in right wing (taxi light)
* Coax cable in right wing for nav antenna in wingtip
* Pitot and AOA tubing in left wing, all the way to the subpanel since the ADAHRS will be there
* Garmin magnetometer in left wing ADAHRS mount

I think that I can run the pitot line in the upper aft systems holes of the left wing all the way to the root, the AOA line in the lower aft systems holes, and the nav antenna cable in the lower aft systems holes of the right wing through the first 8 ribs and the forward systems hole in the remaining 6 ribs.

The only conflicts I see in that plan come from the ADAHRS wiring harness, which connects to the magnetometer in the Garmin installation. That is supposed to run in the lower aft systems holes in the second, third, and fourth ribs of the left wing. It seems likely that the wires will be long enough to run it along with the main wiring harness in the forward systems holes.

In the right wing, there is no conflict, the coax cable would just cross over the main wiring harness between the sixth and seventh ribs.

What have others with Garmin avionics and a wingtip nav antenna done?

I used some PEX to make a conduit for both wings:

https://turnerb14a.blogspot.com/2018...g-systems.html

https://turnerb14a.blogspot.com/2018...date-wing.html

It came in handy running cable for Archer wingtip antenna as well as heavy 14Ga wire to pitot heat. Plus a bit of future flexibility.

Vans sent me a document about upsizing the bushings in the wing ribs and adding additional holes but I can't find it now, you might check with the mothership. I did upsize and then added a few mostly to separate the AHARS wires from the rest of the harness bundle. Also, you might consider removing the pitot heat power line from the harness and running a separate shielded 14ga cable only for the pitot heat hot and ground.

Found it :) https://www.vansaircraft.com/faq-tec...-in-the-wings/

Thanks. It looks like I can do 0.75? holes with SB750-10 snap bushings in the lower aft systems holes on the first few left wing ribs to accommodate the AOA tube and the ADAHRS wires, and keep everything else as depicted in the plans.

Don't waste your money with shielded 14Ga for the pitot heat. Just take 14Ga red and black, and twist them together for their run down the wing. Shielding does nothing for the magnetic fields untwisted wires will generate.

The controller for the pitot heat generates a lot of on-off pulses you probably can just have a plain on-off switch on your panel and do fine; then there is almost no current impulse except for turning it on. I had tons of problems with the controller and none when I got rid of it.

I?ve read about problems with the regulated pitot heat, so I opted for the straight heated pitot mast. Thanks for the advice on twisted wires rather than a shielded one. Any thoughts on running it with the main harness vs. separating it by running it through lightening holes?

My plane is outfitted very much much like yours. There's a lot of "stuff" in the wing!

I used Springfast grommets. What a great product. Fast, neat, and used on certified aircraft.

I checked with the Mother Ship and they didn't really like the idea of drilling another hole in the RV-14 rib. The additional/optional hole shown on the Van's web site is for the 7 & 8 ribs. They didn't say I couldn't, they just didn't like the idea. In addition, going back and drilling/deburring those holes after the wing had the top skins on didn't excite me.



I'm using a GMU-22 magnetometer mounted on the wing tip and Garmin want's the VOR antenna in the opposite wing so I ran the conduit above (Van's) in both wings.

Springfast grommet material is VERY fast to install. The conduit is held in place by zip-ties.

These might help
 

These standoffs made by Panduit are frequently used in certified aircraft and are designed to be secured to the sides of lightning holes. They also have an offset for the lightening hole flange so they are secured to the flat portion of the rib, not compromising the structural integrity of the lightening hole. They come with several screw/rivet attachment hole sizes, as well. Just another idea. Hope it helps someone. https://www.panduit.com/en/search.html?q=Lhms

I used these type of stand off for the conduit, very secure and light.

https://www.homedepot.com/p/SharkBit...1A10/202032968