Effect of Maneuvering and Gust Loads on the Two-Speed Shift Dynamics of a Helicopter Equipped with a Dual Clutch Transmission

This paper explores the effects of maneuvering and gust loads on the drive system and flight dynamic response of a single main rotor helicopter equipped with a two speed dual clutch transmission. The authors demonstrate that performing upshifts during certain maneuvers can significantly reduce the transmitted clutch frictional torques and the resulting clutch pack temperature rise during gear changes. For example, compared with an upshift in level flight, performing a 8° pitch-up maneuver reduced peak clutch frictional power dissipation by 63% (from 455 Hp down to 169 Hp) and reduced total upshift time by 37% (from 5 seconds down to 3 seconds). This results in an 83% reduction in total heat energy dissipated by the clutch during the upshift. Since the design of the clutch pack mass is directly proportional to the heat dissipation requirements, this new (Maneuver Assisted Shifting) MAS technique could enable significant weight savings and clutch wear reduction in helicopter two-speed transmissions.