A METHOD OF BALANCING 8-CYL. 90°-V ENGINE

Abstract

The 8-cylinder 90°-V type engine is now much used for aerial navigation, but one of the great defects of this type is that it has strong vibration. As the symmetrical crankshaft is generally used, the second harmonic of the inertia force due to reciprocating mass remains unbalanced, and the resultant becomes a strong unbalanced force. If the shape of crankshaft is made so as to balance the second harmonic of the inertia force, the resultant of the primary becomes a couple the magnitude of which is proportional to the square of number of revolutions and the direction of which is rotating with the same speed as the crankshaft. So this couple can be easily balanced by attaching balance masses of proper magnitude at proper positions. Thus by using the unsymmetrical crankshaft one of the greatest defects of this type can be eliminated.