Ways of decreasing noise impact on operator by changing ro-tary-screw propulsion units natural frequency of vibration

Calculation results of rotary-screw propulsion units' natural frequency of vibration in order to lower structure-borne noise level at the operator's workplace are presented in this article. One of the most effective ways of noise-reduction is changing base cylinders length. Also, the base cylinder diameter has a considerable impact on natural frequency of vibration - and its wall thickness has the minimal impact. A design solution is suggested using four independent rotors instead of two, allowing to decrease three-times the vehicle natural frequency of vibration.