So, because it is supported at number of points it will give rise to torsional vibration and that
torsional vibration will be a function of, one of the main variables of the torsional vibration
will be the propeller mass- will it be mass, when you talk about rotation will it be mass? It
will really be moment of inertia, mass moment of inertia. So, it is necessary to calculate the
mass moment of inertia, which must be supplied by the manufacture to that designer to do his
torsional vibration calculations- longitudinal, sorry, torsional that is, what we call- shaft
alignment calculations, which is related to torsional vibration.