Grommet Hole in Longeron

[mcattell]

Does anyone know if it's okay to drill a 7/16" hole in the F-713 longeron for a small wiring grommet? I'm trying to route wiring under the rudder cable and it would give more clearance to drill a hole through the longeron. I was also thinking about drilling a hole in the F-719 skin stiffener above that. Both of those are only 3/4" angles so there's not a lot of extra room.

If I don't drill a hole, what have some of you done to get under the rudder cable? I prefer to route the cable up near the middle panel bulkhead instead of going all the way to the firewall.

[Mel]

That's a pretty big hole for a longeron. The longerons are structural. I don't think I would be comfortable with this.

[mburch]

I'm not 100% sure what your aim is, but if I was trying to run a wire down the side of the forward fuselage, I think I'd probably run it down either the aft side of the firewall or down between the F-704C/D center section uprights. Putting a big hole in the longeron seems like a way to accidentally break the plane in half!

good luck,
mcb

[Captain Avgas]

Originally Posted by mcattell

Does anyone know if it's okay to drill a 7/16" hole in the F-713 longeron for a small wiring grommet? I'm trying to route wiring under the rudder cable and it would give more clearance to drill a hole through the longeron. I was also thinking about drilling a hole in the F-719 skin stiffener above that. Both of those are only 3/4" angles so there's not a lot of extra room.

If I don't drill a hole, what have some of you done to get under the rudder cable? I prefer to route the cable up near the middle panel bulkhead instead of going all the way to the firewall.

I truly doubt the wisdom of builders asking such important structural questions on an internet forum like this. Even if respondents said "go ahead", would that mean anything. It might just be the blind leading the blind. I mean, do you really want critical engineering advice from cab drivers and firemen (with apologies to all the cab drivers and firemen out there who undoubtedly do a great job of driving cabs and putting out fires!!!).

You need a qualified aeronautical engineer with intimate knowledge of the RV aircraft design to answer your question.....in other words go to Vans. And they're virtually certain to say no. But at least you really know where you stand.

My best guess is that Vans will tell you that a 7/16" hole in that location will result in the loss of WAY too much metal and might result in eventual structural failure. And additionally, in the event of a crash landing you might just end up with an imprint of your AH in the middle of your forehead as the cabin area concertinas to nothing.

Tell us what Vans says.