I recess the clevis into the firewall and provide a secure slop free
connection that allows perfect idle trim every flight and keeps oil out of the fuselage.

Start with a 1-1/4" length of 1/2" o.d. K&S brass tube. Sharpen the i.d. of the tube and use it to cut a piece of 1/4" thick balsa. Glue the balsa in place with thin ca, soaking it. Hit it with kicker. Now drill a hole in the center of the balsa slightly smaller than the od of your throttle cable jacket and ca the jacket into the balsa so it is flush with the inside of the balsa. Check the throttle arm movement and mark the center of the arc on the firewall then drill a 1/2" hole with a brad point bit. Glue the 1/2" brass tube/cable jacket flush with the firewall. Solder a threaded adapter onto the cable, screw on a ball link and insert into the recessed jacket.  Mount ball on throttle arm and connect other end to servo. The tube only has to be as long as the fitting it will receive plus the thickness of the balsa and the diameter only has to be as large as need be but I always use 1/2" tube to make up for the arc and the fact that I may drill the hole a little off.

On my GP Super Chipmunk I had a clearance problem because I lowered the tank.  I installed the assembly a little lower and angled it up toward the throttle arm and ca'd in place.

The photos show a Saito 91 in a Funtana 40.

Click Thumbnails for larger images.

Brian Jolicoeur