Dale,
I thought of a similar clothespin and cable system years ago but the club members said the cable would flex if it was not anchored along the way to the joystick, as if will between servo and rudder/ elevator. Anyway, after using the pneumatic device for a while I realized that I really need rudder for ground control on takeoff and landing. The pot in front him of my mouth would give me throttle and rudder control with my tongue. I may sound greedy, but I really want both.

Doug