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How to run conduit for rudder trim?

BryanG

Member
New builder question.

Working on adding electric rudder trim. I've never routed any wires or conduit and wondering what the best/most correct way to do it might be.

I'm in the planning stages so any advice is appreciated. I was leaning towards running conduit so I don't have to worry about selecting wires, connectors, etc. now since i haven't done that research yet. I have attached a picture with some of the parts to get an idea of what I'm looking at.

So to summarize:
1. Conduit or just run wires?
2. What routing should I take in the rudder?
3. How do I connect said conduit/wires securely to the rudder?

I have ideas and I've done plenty of googling but I haven't been able to find specific enough information that makes me comfortable i'm on the right track.

Thanks for any help.
-Bryan
 

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2. Remember you want/need to keep the moment aft of the hinge as small as possible. If nothing else run the conduit as far forward as possible.
 
2. Remember you want/need to keep the moment aft of the hinge as small as possible. If nothing else run the conduit as far forward as possible.

I was considering the following routing as well, I'm mostly unsure about the best way to secure the conduit along its path.

Thanks for the input.

-Bryan
 

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Click bond or weld mount wire tie attachment running down the side of the forward edge of the spar.

http://www.weldmountsystem.com/products-fasteners-wireties.php

I think weld mount is a bit cheaper than click bond.


As far as the momentum CG comment it would make more sense to move the servo as far forward towards the spar as you can. This might mean having to build a longer pushrod.
 

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That's what I'd suggest too. I didn't use any conduit, and keep the wires forward.

Also, I doubt you'll find a workable way to use conduit between the aft tail and the rudder.
 
+1 What everyone else said, plus;

Make sure the wire does not flex over a short distance or they will fatigue and break over time with rudder activation. I fixed my wires high in the rudder and low on the fin to allow a long piece of wire to take the flex. Another way is to take a length of wire and make a coil by wrapping it around a pencil or something, like an old phone cord. (Showing my age) That way the flexing of the wire is over a large length of wire avoiding fatigue with rudder movement.
 
Click bond or weld mount wire tie attachment running down the side of the forward edge of the spar.

http://www.weldmountsystem.com/products-fasteners-wireties.php

I think weld mount is a bit cheaper than click bond.


As far as the momentum CG comment it would make more sense to move the servo as far forward towards the spar as you can. This might mean having to build a longer pushrod.

Vans order number "HW-00004" is a $0.35 cable tie holder that has one hole for a screw/rivet. That is the one they use in their plans to route the tail light cable.
 
Is this all thats needed to have an effective rudder trim? While its not as fancy seems like a really easy way to add the trim.
 
Through the fiberglass bottom fairing

I have electric elevator and aileron trim, both wire bundles just have flexible sheathing over them and pass through simple grommets . If I were doing rudder trim, I'd run mine down through the rudder into lower fairing and into the fuselage with same wire I have going to tail beacon. A multi wire plug would facilitate rudder install, but add weight/failure point. You could just terminate splice at servo and leave service loop. If you send a message to Pat Hatch (On here), he has a very nice rudder trim on his -6 he may share details about. At the point of assembly you are in, you may want to entertain an integrated tab similar to the elevator tab for a better look over all. I did that with my aileron trim tab, and glad I did. A bit harder to make/install, but the end result is nicer. I don't know if the zipper T/E is an issue though.
 
Thanks for all the input, here is a picture of what we ended up doing.

-Bryan
 

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