Patent ID: 8336290

Claim:
A propulsion apparatus comprising: axially spaced apart counter-rotatable forward and aft rows of forward and aft propellers mounted on forward and aft rotatable frames respectively and rotatable about a centerline axis, a flowpath passing through the forward and aft rotatable frames, forward and aft pitch change systems including hydraulic rotary forward and aft pitch change actuators mounted on the forward and aft rotatable frames and connected to and operable for controlling and setting pitch of the forward and aft propellers respectively, forward and aft rotatable struts of the forward and aft rotatable frames respectively extending radially across the flowpath, the forward and aft pitch change actuators mounted radially inwardly of the flowpath in a one to one ratio with the forward and aft rotatable struts of the forward and aft rotatable frames respectively, and one or more forward and aft rotatable shafts extending through one or more of the forward and aft rotatable struts and connecting one or more of the forward and aft pitch change actuators to one or more of the forward and aft propellers respectively in a one to one ratio.