Face Gear Transmission Development Program at Sikorsky Aircraft

Abstract

Sikorsky Aircraft, under a cooperative agreement with AATD (Aviation Applied Technology Directorate), has launched a four-year program, RDS-21 (Rotorcraft Drive Systems for the 21st Century), to develop face gear transmissions. RDS-21 addresses key technologies needed to enhance the drive systems of the objective force aircraft while developing new technologies to support the development of a new face gear drive system for Unmanned Air Vehicles (UAV) and the Future Utility Rotorcraft (FUR). Some of the initial funding for face gear development came from a partnership with Army MANTECH. This paper presents an overview of the RDS-21 face gear program and summarizes major milestones achieved to-date. Sikorsky has pursued face gear technologies by partnering with two key institutions. The GearLab at The Ohio State University has developed face gear analysis and design software while the other partner, Gleason Pfauter Inc., has developed face gear manufacturing technology. The methods developed for the design and analysis of face gears and some of the results of their application are covered in this paper. A mathematical model of the face gear generation process is created. The model facilitates the calculation of quantities of interest such as sliding velocities and contact ratio. Digital master gears are created for inspection purposes. A gear analysis software package is used to compute the loads and stresses in the gears. Work is continuing at The Ohio State University to create proprietary face gear analysis software for Sikorsky that can quickly run many design configurations.