HYDRAULIC SYSTEM FOR FAN PITCH CHANGE ACTUATION OF COUNTER-ROTATING PROPELLERS

摘要

Spaced apart counter-rotatable forward and aft rows of forward and aft propellers are mounted on forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators on the frames are operable for controlling pitch of the propellers. A hydraulic fluid supply outboard of the frames is connected to forward and aft rotary unions which are operable for transferring hydraulic fluid between forward and aft union stators to forward and aft union rotors mounted within the forward and aft rotary unions. The forward union rotor is operable to transfer the hydraulic fluid from the forward rotary union to the aft pitch change actuators and the aft union rotor is operable to transfer the hydraulic fluid from the aft rotary unions to the forward pitch change actuators. The forward and aft rotatable frames counter-rotatably mounted on a structural frame located forward or aft of the propellers.