Taxus812

I am getting my feet wet with pull pull cable and starting with the rudder on a scale SE5a. One question I had I am hoping you can answer. The SE5a has cables running from the rudder to the peddles at a slope. I want to keep this same slope but I have to locate the servos further forward. I toyed with all kinds of direct routes, using a bell crank and then a pushrod to the servo etc. I hated all the solutions I came up with. It would be easy if I could simply run the cable through plastic antenna tube to guide it through the fuselage but bend it once inside 5 deg so it aligns with where I want the servos. My concerns is of course wear and eventually binding.

Can you route pull-pull cables through a guide tube allowing it to bend (well supported of course) ?

R8893

My Feedback: (20)

I did just what you suggest in my Handley Page O-400. I used a piece of music wire with bits of plastic tubing acting as "pulleys" at the bend location. I don't fly it very often, but no problems so far First photo shows the rollers, second is the servo and tiller bars lin the nose. Cables to both rudder and elevator..

Taxus812

While that is a good idea (and has me rethinking it) I meant run the cable inside the plastic tube. Making the 5 deg a gradual curve with supports on the tube the entire length. The other idea I had was to use brass tubing to do basically the same thing but it would end when the curve is complete.

RBACONS

My Feedback: (3)

I do it all the time using Sullivan's .032 brass plated cable/housing, p/n S522. I normally try to make the runs as straight as possible but sometimes have bends in the housing tube, particularly at the cable exit points. I've never seen any signs of wear on the housing tube.

Rodney

I also do this all the time. I place a nylon tube anchored well to the structure and can make quite drastic curves in the routing with no problems to date. I've been doing this for many years on the quarter scale planes. I use nylon coated braided fishing line for the cables, 30# test is more than adequate, One of the main cause of problems with pull-pull is that most put to much tension on the cables; you want just enough to not have any sag with the controls at neutral. I always put in a bit of positive Ackerman in the mechanical setup so there will be a wee bit of sag on the non pulled cable as the surfaces move off neutral.