变直径旋翼直升机飞行性能研究

Helicopter Flight Performance Improvement by Variable Rotor Diameter

为了研究旋翼直径变化对直升机性能的提升作用,将旋翼动力学综合模型与机身模型相耦合,采用前飞配平方法计算稳态时旋翼操纵量和机身姿态角,从而计算直升机需用功率。通过研究直升机功率与旋翼半径、前飞速度、直升机起飞重量以及飞行高度之间的关系来确定直升机需用功率的降低幅度,同时也分析了旋翼桨距和机体倾斜角随旋翼半径和前飞速度的变化趋势。在中高速飞行时,特别是高速飞行时,旋翼半径的变化可以显著地提升直升机的性能。当飞行速度为200km/h、旋翼半径减小20%,需用功率可降低37.6%。随着飞行高度的不断增加,在低速到中速飞行时直升机功率减小幅度会减小,在高速时功率减小幅度会增大。旋翼总距和纵横向周期变距随旋翼半径减少而增加,机体纵横向倾斜角随半径减小而减小。

To investigate the performance improvement of helicopters by varying rotor diameter, a com- prehensive rotor model is combined with a fuselage model. A propulsive trim method is introduced to obtain the pitch controls and fuselage attitude in steady states and then the helicopter power required. The helicopter power with rotor radius, forward speed, helicopter weight and fight altitude is investiga- ted to explore how much power reduction can be achieved. The pitch controls and the tilt of fuselage with rotor radius and forward speed are also addressed. Varying rotor radius can achieve significant heli- copter performance improvement in medium to high forward flight, especially at high speed. 20% reduction of rotor radius can reduce the power by 37.6 % at the speed 200 km/h. The power reduction decreases in low to medium forward flight and increases at high speed with increasing flight altitude. The collective and cyclic pitches increases with decreasing rotor radius, and the longitudinal and lateral tilt of the fuselage decreases.