Variable pitch propeller module for an aero gas turbine engine powerplant

摘要

A variable pitch propeller module includes first and second multi- bladed propellers arranged to be driven in opposite rotational directions by a reduction gear mechanism, via shafts. First and second drums are rotatably mounted on the hubs of the first and second propellers and the drums are arranged to rotate the blades of the propellers. A hydraulic motor is mounted coaxially on and rotates with the second propeller, the hydraulic motor being arranged to drive the drums by via a pitch change gear assembly. A hydraulic fluid feed tube extends coaxially through the reduction gear mechanism and both propellers to supply hydraulic fluid to the hydraulic motor. An annular sleeve is positioned coaxially on the tube. The hydraulic fluid feed tube has passages and the sleeve has passages which are aligned to allow hydraulic fluid to flow to the hydraulic motor to vary the pitch of both blades. The feed tube and sleeve are moved axially to control the flow of hydraulic fluid to the hydraulic motor.