直升机涡环状态边界的飞行试验研究

直升机涡环状态边界的确定对直升机飞行安全具有重要意义。为验证辛宏，高正通过模型试验得出的理论涡环边界线，研制开发了一套涡环状态边的机载测试设备，制定了一套飞行试验方案，在R22直升机上进行了飞行试验，通过试飞，明确了直升机进入涡环状态的首要特征现象是机头开始出现航向摆动，摸清了直升机进入涡环状态后的一些运动规律。通过对试飞数据的处理，得到了实测涡环边界线以及对应的临界垂直下降率和安全下滑角，本文首次提出了涡环状态过渡区的概念，指出当直升机进入过渡区时应立即顶杆增速，便可有效改出涡环状态，同时也得出结论，直升机一旦陷入涡环状态，如不施加有效操纵是不会自行退出的，并且愈来愈严重。

Flight Test Investigation of Helicopter Vortex-Ring State Boundary

To predict helicopter vortex ring state boundary is necessary for flight safety. In order to va lidate the theoretical vortex ring state boundary provided by Xin Hong & Gao Zheng based on model tests, a set of on board measure instruments are specially developed and the flight test is carried out on a R22 helicopter. According to the flight test, it is clear that the most distinct cue of starting to get into vortex ring state is the appearance of heading oscillation, and some kinetic regularity after sinking into vortex ring state are detected as well. Based on the flight test data, a new practical boundary is obtained, which was almost parallel with the theoretical one, and the critical vertical descent velocity and the angle of safety descent are redefined. The concept of transition region of vortex ring state is introduced, and it can be sure that once helicopter gets into vortex ring state transition region, rapidly pushing stick forward would make the helicopter recover from it timely. The helicopter will never form the terrible state automatically without proper handing of pilot.