propellers螺旋辊propellern.螺旋桨；推进器=propellor.propeller shaft thrust spring螺旋桨轴推力弹簧propeller-measuring machine螺旋浆要素测量器propeller fluctuating pressure螺旋桨脉动压力propeller load characteristics螺旋桨负载特性propeller diameter diminishing螺旋桨切割直径propeller-type current meter旋桨式海流计propeller-type water turbine螺桨式水轮机propeller shaft turning wrench螺旋桨轴扳手propeller-balancing apparatus螺旋桨平衡台propeller propulsive efficiency螺旋桨推进效率