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Fuselage Conduit Source for 5/8" holes

T

tgmillso

Well Known Member
Sponsor
Hi All,

I ran the Van's 5/8" fuselage conduit in the wings through the corresponding 3/4" holes and was very happy with it. I'm now looking at running a similar setup from under the seat bottom in my RV-7 all the way to the tail, stopping just aft of the F-711 bulkhead. I have drilled all the holes already (apart from the one through the F-710 and F-711 bulkheads as I'm not sure exactly where to put it) but I'm now looking for some conduit that will fit these 5/8" holes that were originally intended for snap bushings. The Van's conduit was very light and seemed pretty crush proof in that you could fasten it in place with an adel clamp (as I will be doing in the elevator pushrod tunnel). Has anyone had any luck sourcing such light weight conduit that works for these holes? The closest I can find is the 0.64" ID, 0.84" OD conduit from McMaster Carr, but I'm not sure how light it is, and if the ID is still too small, making it too tight to fit through the 5/8" holes (0.625"). Can anyone throw any solutions in my direction?
Thanks.
Tom.
http://www.mcmaster.com/#flexible-conduit/=14nvvh2
 
Not corrugated, but I ran black poly irrigation tubing through my holes for wires. Easier to pull wires as well. Comes in several sizes.

Greg
 
1/2" poly pipe from Lowe's works well. It fits in the existing snap bushing holes and is just large enough to do any wing wiring you want. It is also durable and light.

Carl
 
rapid_ascent said:
Tom,

This looks to be the same type of conduit in a smaller diameter.

https://www.amazon.com/Uxcell-Flexible-Corrugated-Conduit-Tubing/dp/B018HX12YO/ref=sr_1_2?ie=UTF8&qid=1476879307&sr=8-2&keywords=flexible+conduit+16mm
.
Click to expand...

I think that one may be a little small in diameter. The OD is listed as 16mm which is 0.629", so it is only 4 thou greater than the diameter of the hole. Perhaps a little loose.
Regarding the use of poly irrigation line, the problem is finding imperial dimensions here. Everythings metric, which makes it really hard finding things that fit. I may have to head into town with a snap bushing and see what I can find. At the end of the day, I guess I can always put some globs of sikaflex around it to keep it in place. I just really liked that flex tubing (apart from the task of feeding it through the holes).
Tom.
 
Results

I went on a bit of a research mission today and finally found a conduit that will work. It's sold here as a 12.8mm ID flexible conduit. It's a little loose in the 5/8" diameter fuselage holes we had drilled (i.e. it just holds but you can pull it through with relatively low force) and it is best suited for a 9/16" hole instead of the 5/8" I have drilled in most of the ribs. That said, the forward most position of this fuselage conduit will be held up under the seat floor with an adel clamp, so it doesn't matter. There will be two more adel clamps in the tunnel, then at the F-706, F-707 and F-708 bulkheads, I will just use sikaflex pro or 291, to bond it in place. I have not yet drilled the F-710 and F-711 bulkheads, so I will drill these to 9/16" which should make a perfect fit. As a final thing, this works out to be the lightest conduit installation option. There's about 3.3m that is needed (from just aft of the mainspar to the F-711 bulkhead), so this works out to be 74 grams or 0.16lb. Not much extra weight considering the ease of running wires in the future. This is important to me, as I will be doing my avionics/wiring near the end of the project after I have riveted the aft section in place. I'm having trouble uploading images right now, but will put up a summary of my data later when I can get it working again.
Tom.
 
Data

Here's some of the data I collected yesterday.

ok0v4p.jpg
 
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