Bellcrank

Bellcrank
The pivoted wood, metal, or plastic arm which converts the motion of the control lines to up-and-down movement of the elevators in a control line model aeroplane.
See also: Servo.

Control Bellcrank: Free without looseness
In this picture you can see the tail rotor pitch control bellcrank. When the pilot moves the pedals, the push/pull tube moves forward and back and operates the bellcrank.