please don't anybody mistake me for a man who thinks it's easy - but external effects like 'gyroscopic' reaction (or bumps in the road) ......
are probably not the killers .....
to a 120000 rpm 200 kW machine given pulses of mechanical energy at some kHz from conversion of electrical energy pulses or vice-versa
whose rotation is driven by turbine blades vibrating at some kHz in gasflow whose 'pulse' vibrations at 5-600 HZ we farm for ICE and PU power
and whirling force effect of even perfectly smooth 120000 rpm rotation are far greater than externals from vehicle body movements eg gyro effects
high frequency external vibration may add to the underlying 'whirling' contribution to transverse vibration of the shaft