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。

The Sikorsky X2 has a pusher propeller mounted at the rear to obtain its high forward speed.

美国西科斯基公司的X2拥有一部安装在后方的推进螺旋桨，这使它获得高速的前飞速度。

Instead, slight speed variations on each propeller perform that function automatically.

取而代之的是，它能自动调整使每个螺旋桨以稍有差异的速度运转。

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。

Also let us adjust the size or pitch of the screw propeller, then try to get high-speed running.

也让我们调整大小或摊位的螺旋桨，然后尝试获得高速运行。