Abstract: A vibration dampening means and method for substantially reducing the vibrational frequency of a multi-cylinder air-cooled airplane engine. The engine driving a hydraulic governor pump for a propeller servo. The servo controlling the blades of a variable pitch propeller. The dampening means including a resilient member mounted on the cooling fins of the cylinders, a hydraulic dampener connected with the hydraulic governor pump, and resilient dampeners mounted on the propeller blades.

Abstract: A vibration dampener for an engine with cooling fins on its cylinders is an integrally formed resilient material member with a first portion having lug portions mountable on opposite sides of cooling fins and between adjacent cooling fins. The lug portions in their outer end portions are of reduced size relative their inner portions, and are wider in their inner end portions than the distance between the fins. Connected ends of the first portion traverse ends of the cooling fins. The vibration dampener is constructed and adapted to be mounted and held in place on an engine solely by friction with the lug-like portions compressed between cooling fins. It reduces the vibrating frequency to which the cooling fins on the cylinders can be forced by normal operation of the engine to prevent the engine from reaching a resonant frequency.

Abstract: The invention is a ventilated snap-ring groove in a machine housing subjected in operation to vibration. An aperture therein has a snap-ring groove. A conduit in the housing or the like communicates between the groove, and a point exterior of the housing or the like. The housing is, for example, an aircraft engine crankshaft counterweight.