Abstract
To reduce a helicopter's rotor noise, a research on variable rotor speed transmission (VRST) was commenced. The variable speed mechanism comprises a high speed traction drive variator and a planetary differential. The traction drive input speed is 23,000 rpm to reduce weight and it is much higher speed than the automotive experience. With this system, the rotor speed can be variable from 80% to 100% continuously and 5 dB noise reduction can be achieved. To substantiate the high speed traction drive, an traction drive element test was conducted first and expected power transmitting capability under 23,000 rpm has been demonstrated. Then a full scale CVT with power split system was tested and power transmission capability up to 767hp was demonstrated. This proved the feasibility of the traction drive CVT for aircraft applications.
