Supplementary Charts for Estimating Performance of High-Performance Helicopters

Charts published in NACA TN 3323 for estimating the performance of high-performance helicopters were applicable to rotors having hinged rectangular blades with a linear twist of 8 deg. Supplementary charts are presented herein covering twists of 0 deg and -16 deg. Charts for estimating the performance of high-performance helicopters were published in reference 1. Those charts are applicable to rotors having hinged rectangular blades with a linear twist of -8 deg. Although the effect of blade twist on the rotor profile-drag power is not very significant at certain flight conditions, differences in profile-drag power between blades of different twist can become appreciable at other flight conditions, particularly at high tip-speed ratios. Accordingly, charts similar to those of reference 1 were prepared, covering twists of O deg and -16 deg and are presented herein.