According to the above configuration, since a hollow part is formed in the rotating shaft, the weight of {HEAD ~ the rotor} can be reduced with hardly any decrease in the natural frequency of {TAIL ~ the rotor} 
According to the above configuration , since a hollow part is formed in the rotating shaft , the weight of { HEAD ~ the rotor } can be reduced with hardly any decrease in the natural frequency of { TAIL ~ the rotor }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL