报告题目：Autorotation Performance of Multi-Rotor Aircraft with Partial Power Loss
亚洲通： Dr. Jianhua Zhang (The Pennsylvania State University)
Autorotation and one engine inoperative (OEI) performance of any rotary-wing aircraft is very important for safe landing or continued flight in case of engine failure. Although the initial kinetic energy stored in the main rotor is essential, a good choice of control schedule is vital to wisely use the available energy (both kinetic and potential) to achieve a successful landing or fly-away. Therefore, various studies have been conducted in the past to evaluate helicopter autorotation characteristics using optimal control techniques, This study is to extend the Army DESCENT simulation program of single main rotor to multi-rotor aircraft. The X-15 tiltrotor aircraft, CH-47 type tandem rotor helicopter, and X-2 compound helicopter with a pusher propeller are the three multi-rotor configurations studied. An analytic model has been developed and integrated with a path optimization program, which is capable of predicting the autorotational performance of multi-rotor aircraft after partial power loss. Both partial power forced landing and recovery to fly away are investigated at different initial altitude and forward speed conditions. The characteristics of optimized flight path and controls are identified and discussed for each type of aircraft. High resolution height-velocity diagrams are generated to illustrate safe flight profiles of the aircraft after partial power loss.
Jianhua Zhang currently is a research faculty at Rotorcraft Center, Department of Aerospace Engineering at Pennsylvania State University. He received B.E. and M.E. in Aeronautical Engineering in 1987 and 1990 from NUAA. Between 1990 and 1966, he was an aeronautical engineer at China Helicopter Corp. of AVIC. He graduated from Penn State University in 2001 with Ph.D.in Aerospace Engineering. He has more than fifteen years of extensive experience on Rotorcraft Dynamics, Aerodynamics and Aeromechanics, and has been working on many rotorcraft related projects with NASA, Army Research Lab, ONR, and rotorcraft industries. He has won NASA Group Achievement Award for his work on composite rotor blade design and analysis in NASA Heavy Lift Rotorcraft Systems Investigation in 2007.