变转速刚性旋翼性能与载荷风洞试验

为研究转速变化对旋翼性能与振动载荷的影响，研制了一副无铰式刚性缩比模型旋翼，开展动力学和马赫数相似的悬停试验与风洞试验。试验研究不同旋翼拉力和吹风速度时变旋翼转速对配平、性能、桨叶与拉杆载荷、桨毂载荷等多个方面的影响，以性能和交变载荷的重复性与周期性证明试验结果是可信的。结果表明：降转速可降低旋翼悬停和前飞状态的需用功率，且拉力越低效果越明显；降转速对桨毂振动载荷影响不明显，但增加了配平所需的周期变距操纵，会增加桨叶与变距拉杆的旋翼转速频率振动载荷，对旋转部件疲劳寿命不利；变旋翼转速应避开旋翼固有频率，防止因共振而导致交变载荷增大。

Wind tunnel test of variable speed rigid rotor performance and load

In order to study the influence of rotating speed variation on the performance and vibratory load of rotor, a scaled hingeless rigid rotor was developed. The dynamic scaled and Mach number scaled hover test and wind tunnel test were carried out. Rotor trim, performance, blade and pitch link loads, hub loads and some other aspects were studied by changing the thrust, airspeed and rotating speed. The credibility of the test results was proved by the repeatability and periodicity of the performance and the vibratory load. Results indicated that the power required can be saved by reducing the rotor speed for both hover and forward flight, and lower thrust showed higher effectiveness. The amplitude of vibratory hub load was not obviously increased by reducing rotor speed. The frequency of rotor rotating speed vibratory blade load and pitch link load increased, because the cyclic pitches were greater in trimmed condition for slower speed, which was adverse to the fatigue life of the rotating parts. Natural frequencies of the rotating blade should be avoided for varying the rotor speed to prevent enlargement of the vibratory load caused by the resonance.