Bellcrank Set 60 Degree

The ballraced 60° bellcrank, for example, is positioned between the horizontal pushrod from the throttle servo and the pushrod running to the barrel arm on the carburettor. When the arm below the ball is vertical the engine is stopped. When the 60° arm is horizontal the engine is at full throttle.
In models with overhead tail rotor (e.g. BK 117, BO 105) this bellcrank can be applied for the tail rotor control.