rceric

I am rebuilding my Sig 4 star 60 that was a kit built by my father. (I crashed it a few weeks ago). I am having trouble getting the throttle cable to work properly. The entire cable and plastic tube that it runs through is bending along the run through the fuselage & fuel compartment when I activate the servo. This eliminates almost any movement at the throttle itself. What am I missing here? Is the outer tube supposed to be secured somehow? Any ideas? The instruction manual has no information and since I do not remember how it was run prior to the crash I am out of ideas.


Thanks in advance!


Eric

plugin

The outer tube must be secured, this makes the movement of the link more consistent. If the pushrod is plastic try replacing it for a metal pushrod, they are more reliable.

RCKen

My Feedback: (9)

Yes, the outer tube needs to be securely fastened to the frame of the plane. To accomplish this use medium CA around the tube where it passes through the firewall. Also do the same thing where the tube passes through any other former on the plane. This will secure the tube so it will not move.

Hope this helps

Ken

rceric

Thanks! This makes perfect sense. I didn't think of using CA to glue that tube in place. I'll give it a shot!

Campgems

Dont forget that a final mount for the tube just ahead of the throttle servo. You want it far enough ahead that the bending action doesn't pinch the cable. I use a 1/4 x 3/8 stock and find the spot I want to secure the servo end. I use two of them and place them together and the drill a hole through the joint between the so i can CA one to the fuselage side and then run the cable shieth through them, then CA the other to lock it down. As long as you have both the servo end and the firewall end tight, the cable will provide that right movement following the servo.

I fly four strokes and the cables give me a lot of flexability over a solid wire. The Four strokes require some interesting paths around the tank and still exit the fire wall at the right place to smothly operate the throttle arm. A solid wire usually won't work without binding. With the cable, just make sure both ends of the sheith are positioned right and are locked down. That determines the movement of the cable.


Don

propbuster

My Feedback: (1)

A metal screw eye works well for a "stand-off" type of mount too. Just find one that accepts the tubing snugly and epoxy.

flyX

For those wire types throttle cable. I usually have to make sometype brace at an angle with a piece of wood near the servo to prevent flexing.
Depening if you're using a 2 stroke or 4 stroke. I use spacers from pcb assembly and slide it over the jacket and glue it to
the firewall to prevent flexing there also. Sometimes I use music wire and make Z bends accordingly.

Villa

I would not depend on just glue to hold the outer tube in place. I like to use the "belt and suspenders" approach. Frequently I use a string such as dental floss to tie the tube to something that does not move. The glue is good to keep the tube from moving in the direction of the tube length.