CONTROLLING RATE OF ROTOR FEATHER BY SYSTEM SECONDARY TO PRIMARY BLADE ANGLE CONTROL SYSTEM

The rotor control system includes a main control valve (25) having an inlet (102) for receiving liquid and an outlet (104) for issuing liquid to a rotor pitch change actuator (24). The rotor control unit is configured to control flow of liquid from the inlet (102) to the outlet (104) to modify pitch angle of rotor blades (17). A feathering system (100) with a first conduit (106) connected in fluid communication with the outlet (104) of the main control valve (25), a second conduit (108) for fluid communication with the rotor pitch change actuator (24), and a drain conduit (110). The feathering system (100) has a normal operation mode for supplying liquid from the main control valve (25) to the rotor pitch change actuator (24) by allowing flow through the feathering system (100) from the first conduit (106) to the second conduit (108). The feathering system (100) has a feathering mode for controlling drainage from the rotor pitch change actuator (24) to the drain conduit (110).