Suspend fresh air vent duct tube - any neat tricks?

[SMO]

I cut a NACA duct in the bottom of my wing to supply fresh air to the rear seat of my Rocket. The duct tube exits out one of the lightening holes in the wing, and I would like to suspend this so it doesn't abrade on the edge of the lightening holes. Thought about using zip ties to do this, but maybe there is a better way?

[Mike D]

There are several ways I can think of.

It could be done like in the RV-10 tunnel. There a piece of aluminum is bent with a L shape on one end, and a hole slightly larger than the duct is cut in the aluminum. This is then screwed to the side and the duct is routed the through the hole. I think this is part F-1051J

But you might want to seal the area from cold air coming in. Then you could make a cloth seal like is done around the push rods. Then just wrap a zip tie around it. This will keep the duct in the center and seal out cold air for winter ops.

[SMO]

Thanks Mike, no need to seal out cold air. The transition to the fuse is sealed.

[David Paule]

You might consider some sort of grommet edging, like this:

http://www.aircraftspruce.com/catalo...clickkey=47656

Dave

[aerhed]

Pop rivet an L tab to th top of th lightening hole and zip tie to it.

[BillL]

Originally Posted by David Paule

You might consider some sort of grommet edging, like this:

http://www.aircraftspruce.com/catalo...clickkey=47656

Dave

Or if you have any left over corrugated conduit, just split it and line the hole the large diameter should protect the tube. Just make sure it is captured (compressed) so it won't come out with g loads.

[blueflyer]

maybe put this on the bottom half of the lightening hole??


http://www.aircraftspruce.com/catalo...?clickkey=5038

edit: I like aerhed's suggestion

[rleffler]

I just used some adel clamps. You can see them where the conduit is coming through the baggage bulkhead. And yes, supports were installed in the other locations too, they just aren't there in this photo.

[SMO]

Thanks for the responses, they sparked some additional thinking. What I came up with is a foam grommet.

I have some 1" foam laying around. I cut a circle out of it one inch bigger than the hole:



I cut a 2" center out of the foam. I put the resulting donut onto the fresh air tube:



I cut a half inch or so into the side of the donut (all around the circumference) with my utility knife and mounted it in the hole like a grommet:



Quick - Took me almost as long to make this post as it took to do the job.
Cheap - Zero in my case but a buck or two at the foam store.
Light - Weighs next to nothing.
Effective - Holds the tube securely, time will tell if it falls apart. Could glue it but doesn't feel like it needs it.

[HIIFLY]

I like the foam , simple and cheep ! Also stops air movement ! Great idea.