2014 年 62 巻 1 号 p. 9-14
Experimental studies are conducted to investigate influence of crosswind on the aerodynamic performance of helicopter rotor hovering in close proximity to the ground with a structure. Experimental parameters are rotor height and relative wind velocity to the rotor and structure. Wind directions considered in this study are the following: 1) wind blows from the structure side to the rotor side, 2) wind blows from the rotor side to the structure side and 3) wind blows parallel to the rotor and structure. In experiments, the rotor torque is measured for various combinations of these parameters while adjusting the collective pitch angle to make the rotor thrust constant. In this paper, the torque coefficient of rotor and collective pitch angle of rotor blade are shown. Experimental results show that behavior of torque coefficient varies in various ways according to combinations of these parameters and the torque coefficient on low speed crosswind condition increases without depending on wind direction compared to that of Out of Ground Effect case.