[AviatorJ]

I don't know how many additional holes are too many on the wing ribs. So far I've run 1/2 CPVC and the Pitot line in the existing holes. I added an additional holes and snap bushings for the AoA line (Green). Now I would like to drill 3 ribs outboard to run my stall warning from the bushing on the spar to the entry into the CPVC at the bellcrank area.

My question is would it be safe to drill the designated red dot area about 1/4 or whatever to use more 375 bushings?

If not following these guidelines I would just drill a hole and use a cable tie.

 

[AviatorJ]

With close to 200 views and no suggestion I went ahead and called Vans. Talking to builder support I decided not to use additional bushing.... The logic is its a single wire so why even worry about the structural integrity by drilling larger holes.

Instead I'm going to drill a #30 hole and then make or buy a bracket to rivet on following the 2D rule. Then I'll just zip tie it.... Now that I think of it I'll need to do the same for the aileron trim wires.

 

[terrye]

Additional holes in wing ribs

I've put 4 wiring holes around my round lightening hole in my RV-9A wing ribs. I wanted to keep high voltage strobe wires and power wires away from antenna wires and autopilot servo wires. Some holes are 7/16", some are 1/2" some are 5/8". In all cases the holes are well clear of the flanging around the lightening hole. The holes are on approximately 7.5" centers and approximately on 45 degree diagonals. In addition there is the pitot line hole at about 9:00 oclock next to the spar on the left side, using the same hole on the right for autopilot servo wires. I think your "red dot" hole would be just fine, as will all holes ensure that it is well deburred to prevent cracks.