Pitch control system for variable pitch propeller.

摘要

A pitch control system (10) for a variable pitch propeller effects engine governor (330), control of blade pitch under normal operating conditions and automatically effects direct (beta) control of blade pitch by the power lever (305) throughout a predetermined range of power lever settings. The system is hydromechanical and comprises a pitch actuator (40) and a pair of control valves (120 and 210), a first of the valves (120) applying a metered fluid pressure from a governor controlled pilot valve to the actuator and blocking that signal and replacing it with a supply fluid pressure at the point to transition from governor to beta control. The second control valve (210) effects a controlled draining of the actuator and connection thereof with the power lever (305).