Ceramic Mainshaft Roller Bearing Performance in a Gas Turbine Engine

The program tests conducted on a modified J402 turbine engine were to demonstrate the feasibility of using ceramic bearings for high speed gas turbine applications with reduced or no lubrication to the bearing. Six engine tests were conducted, each test complementing the next to establish baseline parameters of the test to follow. Test No. 3 was the first to demonstrate the ceramic bearing operation unlubricated at 39,000 rpm and minimum lubrication of 10cc per minute at 41,200 rpm. Engine Test No. 4, which was a repeat of Test No. 3, was successfully completed and demonstrated 33 minutes of unlubricated operation at 39,000 rpm. All engine tests were conducted with the bearing and bearing housing instrumented for temperature read-out during the test. Engine Tests 3, 4, 5 and 6 were also instrumented for lubrication flow pressure and bearing cavity pressure in order to monitor lubrication to the bearing as a function of pressure differential.