ARMY AIR MOBILITY RESEARCH AND DEVELOPMENT LAB FORT EUSTIS VA EUSTIS DIRECTORATE
The report covers work performed during an in-house program to evaluate the effectiveness of using the sound emitted from helicopter power train components as a data source for diagnosing their mechanical condition. A ground-based UH-1 helicopter sonic analyzer developed by the Curtiss-Wright Corporation under Government contracts was used in the evaluation. Sound recordings were made on 87 UH-1 helicopters that had either the transmission or a gearbox scheduled for removal for routine overhaul. The mechanical condition of the components was then noted during the overhaul process, and then results were compared with the recorded signals in an attempt to correlate the mechanical condition with the acoustical signals. The sonic analysis procedures were then revised to improve the effectiveness of detecting component malfunctions.