A unique engine-synchronism indicator for aircraft

RECENT aircraft design has emphasized multiengine airplanes, especially for commercial transports and military types. Two and 4-engine planes are commonplace and 6-engine craft are proposed for the near future. Engine synchronism indication, usually between a master engine and each of the others, becomes more important as the number of engines on the airplane increases. It is possible to synchronize two engines by ear, but this method becomes exceedingly difficult for aircraft with more than two engines.