Performance of Advanced Heavy-Lift, High-Speed Rotorcraft Configurations

The aerodynamic performance of rotorcraft designed for heavy-lift and high-speed cruise is examined. Configurations considered include the tiltrotor, the compound helicopter, and the lift-offset rotor. Design conditions are hover and 250-350 knot cruise, at 5k/ISA+20 degrees Celsius (civil) or 4k/95 degrees Fahrenheit (military); with cruise conditions at 4000 or 30,000 ft. The performance was calculated using the comprehensive analysis CAMRAD II, emphasizing rotor optimization and performance, including wing-rotor interference. Aircraft performance was calculated using estimates of the aircraft drag and auxiliary propulsion efficiency. The performance metric is total power, in terms of equivalent aircraft lift-to-drag ratio L/D = WV/P for cruise, and figure of merit for hover.
Presented at the American Helicopter Society (AHS) International Forum on Rotorcraft Multidisciplinary Technology held in Seoul, Korea on 15-17 October 2007. Published in the Proceedings of the AHS International Forum on Rotorcraft Multidisciplinary Technology, p1-28, 2007. Performed in collaboration with the National Aeronautics and Space Administration (NASA).