Hi everyone! I'm finding that the 0.038" (about 1mm) pushrod wire that comes with FT Speed Build Kits often causes me problems.
For example, I'm now building a Tiny Trainer, and the servos get glued inside the fuselage, with a pushrod wire length of about 13 to 14" between the rudder and elevator control horns and the servo arms. I built everything exactly according to instructions, including the two foamboard-and-coffee-stirrer pushrod wire guides inside the fuse at about 9 or 10 inches. Even so, I'm getting a lot of bowing of the pushrod wire near the servo, which gives me uneven and erratic movement of the control surfaces.
I ended up relocating the servos on the horizontal stabilizer on either side of the rudder, putting cutouts in the stabilizer and gluing the servo flanges to the top surface of the stabilizer. With the pushrod wire now very short, it works OK and gives me even, repeatable control surface throws. I hope it doesn't disturb the flow over the tail too much - we'll see.
I've also built (but not yet flown) another FT design with ailerons -- the aileron pushrods also don't give me much problem, as they are also quite short.
Hasn't anyone else had this problem with tail surface pushrods going well forward into the fuselage? Should I go to a thicker pushrod wire, say 0.047/1.2mm ? Any other ideas?
Thanks!
Steve Rosenbach, Tewksbury MA
"I may be old as dirt, but I'm a newbie RC enthusiast"