A. 航速小于0.70vH、倒车起动转矩为-0.50MH B. 当螺旋桨的转矩为0,航速小于0.8vH C. 倒车启动转矩为-0.75MH,航速小于0.85vH D. 当螺旋桨推力为0,航速小于0.85vH