什么是迎角动稳定性?
参考答案:
迎角动稳定性是直升机的扰动消失后,在恢复原来迎角的俯仰摆动中,由于阻尼力矩的作用,使迎角振荡越来越小,即减幅振荡,最后恢复到原来的迎角。
--Did you enjoy meeting your old schoolmates at the party last week?
--Yes, I did. We ____ each other since we graduated from college.
A.haven’t seen
B.didn’t see
C.hadn’t seen
D.wouldn’t see
异步电动机的转速超过同步转速时,电动机进入发电制动状态。