controllable-pitch propeller[kən¦trōl·ə·bəl ′pich prə′pel·ər]
An aircraft or ship propeller in which the pitch of the blades can be changed while the propeller is in motion; five types used for aircraft are two-position, variable-pitch, constant-speed, feathering, and reversible-pitch. Abbreviated CP propeller.
A propeller whose pitch can be altered by the pilot in flight. Unlike in a constant-speed propeller, where the governor automatically controls the pitch, here the pilot carries out the pitch adjustments. Takeoff is made with a low blade angle, so that the engine develops maximum power. The blade angle is increased during cruise, so that the engine operates at a slower and more economical speed.