To investigate the effect of the blade twist on helicopter rotor performance, a rotor performance calculation model, based on anisotropic composite medium deformation beam model, is derived to predict the power required of a helicopter rotor at any flight speed. The theoretical prediction is consistent with the flight test data, which verifies the effectiveness of the analysis model. According to airfoil distribution of the UH-60 helicopter, the blade is divided into three segments, which are inner, middle and outer segment respectively. And the effect and its mechanism of the three segments on the required power are studied based on the distribution of angle of attack and the lift-drag ratio over the rotor disk. Overall, the faster the helicopter flies forward, the greater the effect of blade twist is. The twist of the inner segment has a negative effect on the rotor performance, but the effect is small. The twist of the middle segment plays a decisive role in improving the airflow environment over the rotor disk, and can reduce the required power by more than 10% in high-speed forward flight. The outer segment is beneficial to power reduction, and the effect is average. A set of piecewise linear twist schemes for each flight velocity are obtained by traversal method, which is better than linear twist scheme in any flight state.
ZHANG Yuhang
,
HAN Dong
,
WAN Haoyun
. Rotor performance improvement by blade piecewise linear twist[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2022
, 43(5)
: 225264
-225264
.
DOI: 10.7527/S1000-6893.2021.25264
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