A design optimization procedure for minimizing drive system weight of high speed proprotors

An optimization procedure is developed to address the problem of minimizing the drive system weight of high speed proprotor aircraft which are required to demonstrate fixed-wing-like efficiencies in high speed forward flight and maintain acceptable hover figure of merit similar to helicopters. The optimization is performed using the method of feasible directions. A hybrid approximate analysis procedure is also used to reduce the computational effort of using exact analysis for every function evaluation necessary within the optimizer. The results compared to a reference rotor show significant weight reductions. The aerodynamic performance of the optimized rotor, analyzed at “off-design” points to judge the, strength of the optimization, problem formulation and the validity of the resulting design, shows-considerable improvements. The results are compared to the reference values and significant reduction in the weight is achieved.