You need to check the helicopter's rotors before taking off.

起飞前你需要检查一下直升机的旋翼。

These rotors are made of aluminum alloy.

这些旋转组件是由铝合金制成的。

This high-speed rotating rotor can speed up the motor speed.

这种高速旋转的电枢可以加快电动机的运转速度。

Chris Retzler has built a prototype of a machine called the wave rotor.

克里斯·雷兹勒做出了一台叫做波转子的样机。

This minuscule rotor wiggled clockwise or anticlockwise as molecules bumped into it from one side or the other.

当分子从一边或另一边撞击这个微型转子时，它会顺时针或逆时针摆动。

As it does, the rotor gains energy.

像它所做的那样，转子取得了能量。

The rotor is at bottom of the picture.

图片底部是转子。

It also removes the need for a tail rotor.

它也无需尾部旋翼。