propellers螺旋辊propellern.螺旋桨；推进器=propellor.propeller velocity sensor流速旋浆传感器propeller balancing stand螺旋桨平衡架propeller simulation unit螺旋桨模拟装置propeller pitch indicator螺旋桨的螺距指示器propeller with ring quard带护环的螺旋桨propeller in stern tunnel尾隧螺旋桨propeller-blade section桨叶剖面propeller with ring guard带护环的螺旋桨propeller blade thickness推动机刀厚度propeller sheet cavitation螺旋桨片空泡