| 摘要 |
A pitch change slide is mounted for longitudinal movement on a propeller shaft hub adapter in turn secured to the engine shaft of an aircraft engine, the said slide carrying a plurality of toothed racks each engaged with a spur gear on the base of one of a plurality of rotatably mounted propeller blades. Reciprocation of the pitch change slide changes the pitch of the propeller blades. The pitch change slide carries a coiled spring. A spring pressure slide, mounted for longitudinal movement on the propeller shaft hub adapter, has a flange bearing against the coiled spring, and is reciprocable on the propeller shaft hub adapter through a control rod operable from the aircraft cabin, thereby to adjust the degree of compression of the spring. Weights are mounted on the propeller blades and generate centrifugal force as the engine shaft turns, the said centrifugal force tending to rotate and change the pitch of the propeller blades. At a selected constant RPM, the compression of the spring is adjusted so as to balance the pitch changing force of the weights and the aerodynamic pitching moments of the blades. The pitch change slide may also be positioned to permit operation in a full high RPM (low pitch) mode, or selectively to a reverse thrust mode. A fail safe feature permits safe operation of the aircraft if the coiled spring should fail.
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