An advanced pitch change mechanism incorporating a hybrid traction driveA design of a propeller pitch control mechanism is described that meets the demanding requirements of a high-power, advanced turboprop. In this application, blade twisting moment torque can be comparable to that of the main reduction gearbox output: precise pitch control, reliability and compactness are all at a premium. A key element in the design is a compact, high-ratio hybrid traction drive which offers low torque ripple and high torsional stiffness. The traction drive couples a high speed electric motor/alternator unit to a ball screw that actuates the blade control links. The technical merits of this arrangement and the performance characteristics of the traction drive are discussed.
Steinetz, B. M. (NASA Lewis Research Center Cleveland, OH, United States)
Loewenthal, S. H. (NASA Lewis Research Center Cleveland, OH, United States)
Sargisson, D. F. (General Electric Co. Evendale, OH, United States)
White, G. (Transmission Research, Inc. Cleveland, OH, United States)