AGMA 05FTM16

This paper summarizes an Engine Transmission Input Pinion SeededFault Test that was accomplished as a portion of the validationprocess for the Boeing Rotorcraft Transmission Vibration DiagnosticSystem (TVDS) Analyzer. The test specimen was a high speed CH47D(Chinook) engine transmission input pinion with a known defect(i.e., seeded fault) machined into a high stress area of a geartooth root. The specimen was operated at “overload” conditions inorder to initiate and propagate a fatigue crack from the seededfault. During the testing, the TVDS analyzer monitored the testpinion real time and successfully provided a sufficient warningtime of the impending failure. (Note: No metallic chips weregenerated during the test). Following testing, the TVDS data(acquired real time) was evaluated along with a post–testfractographic evaluation of the fatigue crack. During thepost–test fractographic evaluation, arrest lines and fatiguestriations were analyzed to develop crack propagation data as afunction of the number of applied load cycles. This datawas thencorrelatedwith the collected TVDS data to better understand thepotentialwarning signals the TVDS system could provide about theimpending failure of a helicopter’s primary drive systemcomponents. In this test, the TVDS analyzer provided a minimum ofeleven minutes warning time (at higher than normal operation loads)of the impending failure, which would allow the pilot enough timeto unload the suspect engine transmission and continue to fly onthe remaining engine.

Edition:

05

Published:

10/01/2005

Number of Pages:

13

File Size:

1 file , 1 MB