Aerodynamic characteristics of optimized blade tip geometries for flight at high advance ratio are identified by wind tunnel tests conducted in October 2020. Several types of high-speed compound helicopters are in the development process today after the successful technology demonstrations. JAXA has been studying a high-speed compound helicopter for emergency medical service since it is expected to help save lives significantly in Japan. In this study, optimized blade shapes are invented, whose high-speed performance is twice as high as a conventional blade shape while maintaining hovering performance. In this paper, an optimized rotor blade with a swept-back angle is evaluated highest among optimized rotors and UH-60A rotor in the items of hover performance, high-speed performance, reduction effect of rotor drive power, control hydraulic system output reduction effect, and static aerodynamic stability. Thus, it is concluded that an optimized rotor blade with a swept-back angle is the most practical from the viewpoint of the aerodynamic characteristics of the rotor blade tips.
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