The result of this ... two - fold ... localized transient cavitation ( in English , not physics ... cavitation which is very short in duration and , from my understanding , usually happening along the propeller disk edgecan causepropeller / shaft vibration
airflow over the wings(passive) caused bypropeller vibrations
varying the airstream velocities(passive) caused bypropeller vibration
constant changes of their rotating speed to compensate the winds(passive) caused bythe propeller vibration
uneven incoming air area of fan inlet , such as not unified baffle opening and closingcan ... causeimpeller vibration
inaccuracies in pitch , camber , and section shape(passive) can be caused byPropeller induced vibration
actuator yoke arms breaking during flightcould causehigh propeller vibration