Rudder cable conduit

[rockwoodrv9]

Rick, you can see both ends and easily take the cable out for inspection. It is easier to get out of the conduit than it is through the grommets along the rest of the cable run. My interior panels will cover the cable anyway so I won't be inspecting it behind the panel each flight but the cable will still be visible near the rudders and directly behind the seat all the way to the rudder itself. If the cable is going to be damaged, I believe there is a bigger change of damage from something or someone in the seat or baggage area causing the damage. That is why there is conduit - to protect wires or cable.

Do you have interior wall panels is your plane? If not, does the rudder cable ever get snagged on anything from seat belts to headset cords?

[Dundee Downunder]

With all due respects, I think the next bay back is the more important. My AP required a semi-rigid tube in this area over the rudder cable to prevent any cable slack catching on the Flap Actuating Rod bolt head snagging the cable and pulling it down when the flaps are lowered.
Even more important if, like most of us, the bolt is put in backwards.
This leaves the nut and protruding threads to catch on the cable.
Simple garden reticulation pipe, slit from end to end and bound with gaffe tape in several places, was sufficient to meet his requirements.
Cheers, Rob
RV-7A VH-MyRV Flying.....(0.4 hours)

[Greg Arehart]

I put mine in 1/4" plastic line all the way front to back. Reasoning was for more protection for the cable from snagging or wearing on anything along the run. No issues in 700 hours.

Greg

P.S. I think it's low enough along the sides nobody would mistake it for a handle of any sort.

[rolivi]

http://www.classicaerodesigns.com/we...tCategoryID=17

I think running it through a PVC conduit with a leather wrap will look awesome

[Scott Hersha]

First thing is, I agree with Rick Gray. Inspection would be hampered and I don't see the upside. Secondly, CPVC, PEX, and other kinds of poly are not sunlight tolerant so that needs to be replaced every couple years in a bright cockpit. Covering the cable with leather or something will help with the UV degradation, but still cover up a potential problem. One way of checking cables is to pass a cloth (nylon?) over the cable to see if it snags, indicating that the cable is breaking down. It would be easier if the cable wasn't sheathed.

Plus...... I don't see how covering a control cable with plumbing lines meant to go behind the walls of your house dresses up the cockpit...

[rockwoodrv9]

Scott,
I have a complete flightline interiors foam with leather covering with built in armrest going on the wall. You will not be able to see the cable even if there was no conduit over it. Not being able to see it IS the reason I am putting it in conduit. The conduit is there to protect it - the same reason conduit is used everywhere. It will be impossible to damage the cable when it is enclosed in conduit.

After thinking about it more and the post about not getting a certificate in Australia until he enclosed the section in back, I think I will run the entire cable in conduit. No chance of damage, snagging, or being pinched between anything.

As for inspection, I can unbolt the cable from the rudder pedal and pull it completely out from the rudder end outside the plane. Can you do that with the grommets used in the bulkheads? How fun is it to crawl back into the fuselage to inspect the cable?

So, there is no chance of sun damage, it is covered by my interior panels, completely protected from end to end, and easy to inspect. Where is the downside? It will add less than half a bottle of water in weight. Good trade in my book.

[ao.frog]

Good idea, but I'm wondering about wear and tear on the spots where the conduit is passing through the bulk heads?
I'd think that if there's even a slightest movement of the conduit in their bulkhead holes, vibration and movement will start wearing down the conduit at that exact spot?

And if/when the conduit has gotten a hole, then I guess the ruddercable will run directly on the edge on the bulkhead without any protection. And that's not good...

I guess you could glue the conduit in place in their bulkhead holes, but then it'll be difficult to remove for inspections.

Just my 2 cents...

[WenEng]

Originally Posted by ao.frog

Good idea, but I'm wondering about wear and tear on the spots where the conduit is passing through the bulk heads?.....And if/when the conduit has gotten a hole, then I guess the ruddercable will run directly on the edge on the bulkhead without any protection......I guess you could glue the conduit in place in their bulkhead holes, but then it'll be difficult to remove for inspections..

He said the conduit would stay in place and by unbolting the rudder cable at the rudder pedals, the entire cable slides out the rear for periodic inspections. Good idea. Regarding vibrating a hole into it, why would that be any different than doing the same damage to a snap bushing? I like the idea...

[ao.frog]

Originally Posted by WenEng

Regarding vibrating a hole into it, why would that be any different than doing the same damage to a snap bushing? I like the idea...

Because a snap bushing doesn't have any movement or vibrate; it's sitting firmly in it's hole...

[rockwoodrv9]

Originally Posted by ao.frog

Because a snap bushing doesn't have any movement or vibrate; it's sitting firmly in it's hole...

The conduit is much firmer in each bulkhead than the snap rings. The snap rings are not nearly as tight as the conduit.

The conduit has no movement because it is tightly cut between the bulkheads and you have to work it to get it through the holes in the bulkheads. There is much less movement of the conduit than the snap rings. A sagging cable sawing back and forward with each push on the rudder pedal will saw through the snap rings many years before it will wear the conduit out.

I added conduit inspection to my annual condition inspection list so I think I will be covered. Im not suggesting anyone else use conduit. I was just looking for things to consider if I used it and I appreciate the responses. Thanks