直升机飞行过渡速度现象研究

Study of the helicopter flight transition velocity phenomena

针对直升机飞行中通过过渡速度时产生的振动、抬头、偏转和倾斜等一系列现象,从旋翼动力学的角度进行了深入的研究,并且给出了系统的解释。首先,分析了旋翼尾涡对直升机状态的影响;然后,研究了桨涡干涉效应,发现桨涡干涉效应导致旋翼前行桨叶平均拉力增加、后行桨叶平均拉力减小,这是引起直升机抬头、倾斜和振动的根本原因;最后,研究了起飞和着陆中通过过渡速度时操纵对策的差异及其原因。

As for the phenomena of vibration,nose-up pitch,yawing and rolling when helicopter flying through the transition velocity,this paper not only studies them from the view of rotor dynamics but also gives a system explanation. Firstly,the influence of the rotor wake on the helicopter condition is analyzed. Then,the effect of paddle and vortex is studied. And it is discovered that this effect makes the lift of the forward paddle increased and makes the lift of the backward paddle decreased. This is the basic cause for helicopter vibration,nose-up pitch,yawing and rolling. Lastly,the difference and cause of the controlling countermeasure used at the transition velocity in the takeoff and landing flight phase are studied.