US Patent 7422419 Propeller blade retention system

A propeller blade mounted with a preload adjacent a propeller blade root retention that increases the moment capacity of the retention for a given pitch diameter, yet permits pitching of the propeller blade about a blade axis in response to a propeller pitch change actuation system. During assembly, the preload condition is established by preload springs which apply a load on the end of a tapered roller bearing set as a floating race is rotated which allows the tapered roller bearing set to progressively push the propeller blade root outboard and the floating race inboard to generate the preloaded condition.