propeller speed

Period characteristics of radiated noise at high frequency is investigated by a method based on short time Fast Fourier Transformation, and propeller speed is estimated.

用短时傅立叶分析的方法研究了辐射噪声在高频段时频变化的周期性，估计了目标的螺旋桨转速。

In order to satisfy the operation requirement of the rated thrust of the propeller, the propulsion motor performs only in rated torque on the low speed, so the motor power is low.

认为以满足螺旋桨额定推力为目的，推进电动机只需要低速输出额定转矩来实现，即输出功率较低。

Practical Measures for Raising Propeller Efficiency of Low Speed Mini UAV

提高小型无人机螺旋桨效率的工程方法

Henry pushed at a lever; there was a click. Slowly at first, then faster and faster, till it was a circular mist before their eyes, the propeller in front of them began to revolve.The wind of a horizontal speed whistled ever more shrilly in the stays.

亨利推了一根杠杆，咋的一声，他们前面的螺旋桨开始了旋转。起初很缓慢，渐渐变快，最后眼前便成了一片圆形的光雾，悬浮平飞的高速风叫得越发尖利了。

The ships maintain or change course and speed by using propeller thrust force and rudder strength.

船舶是借助螺旋桨的推力和舵力来保持或改变航向和航速的。