Large Engine Hybrid Ceramic Bearings

General Electric Aircraft Engines under contract from the Advanced Research Projects Agency (ARPA), has demonstrated the ability of ceramic rolling elements to withstand shock loading conditions experienced during race spalling, has performed a series of full scale tests directed at showing the thermal benefit of large hybrid bearings at speeds up to 3.0 MDN, and has developed a condition monitoring device that detects both ceramic and metallic bearing debris. The details of the three primary tasks are presented in this paper: Task 1 involves the testing of a hybrid bearing operating in severe shock loading conditions, with comparisons to an all steel bearing. Task 2 involves back-to-back comparison of an all-steel high speed bearing to a hybrid bearing of the same geometry and to a hybrid bearing of tighter race curvatures, showing differences between outer ring temperatures of all-steel and hybrid bearings. Task 3 deals with the bench testing of a new ultrasonic bearing condition monitoring device, designed to collect and detect both ceramic or metallic debris.