侧风下直升机水上迫降模型试验研究

Model Experimental Study on the Helicopter Ditching with Crosswind

研究侧风对直升机水上迫降性能的影响具有重要的意义,开展侧风环境模拟技术研究和模型着水试验,研究风扇桨叶角、风扇间距对侧风风速的影响以及侧风风速对直升机模型姿态角、过载和底部压力的影响。结果表明,风扇采用18°桨叶角方案比采用15°或20°桨叶角方案更优;风扇间距比为1.66时侧风风速分布均匀;有侧风时,对模型俯仰角几乎没有影响,横滚角幅值较大且难以稳定;随着侧风速度增大,重心过载逐渐增大、对称面和近侧风端的底部压力增大、远离侧风端的底部压力减小。

Investigating the effect of crosswind on helicopter ditching performance is of significance,designing of a crosswind-fan system and ditching experiment of a helicopter model are conducted.The effect of blade angle and distance between fans on crosswind velocity is investigated.And then the effect of crosswind velocity on attitude angle,overload and bottom-pressure of the helicopter model is also studied.The results show that,the blade angle of 18 degree is better than 15 degree and 20 degree.The crosswind velocity distribution is uniform when L/D equals 1.66.The crosswind is of little effect on pitch angle but makes the roll angle amplitude larger and more difficult to be stabilized.When the crosswind velocity increases,the overload,the bottom-pressure at the plane of symmetry and near crosswind-fan system increases,but the bottom-pressure far from crosswind-fan decreases.