METHOD OF OVERCOMING THE ZONE OF CRITICAL RPM OF MARINE INTERNAL COMBUSTION ENGINE WITH CONTROLLED-PITCH SCREW Russian patent published in 1994 - IPC

FIELD: shipbuilding. SUBSTANCE: zone of critical rpm is overcome in three stages. The first involves attaining rpm of the screw equalling to the lowest boundary of the zone, and the screw pitch is reduced to zero. At the second stage in response to an increase in rpm of the screw within the zone its pitch is reduced to a value ensuring continuous product of current rpm by screw pitch. At the third stage, when the screw revolves at rpm corresponding to the upper boundary of the zone, screw pitch is increased to a magnitude corresponding to this rpm by combinatory diagram of dependence between the pitch and engine rpm. EFFECT: enhanced efficiency of the method. 1 dwg