Advanced Development of a Helicopter Rotor Isolation System for Improved Reliability. Volume I. Summary Report

This report includes the results of the analytical and experimental phases of a helicopter rotor isolation reliability and maintainability (R and M) program on a UH-1 helicopter, which was modified through the addition of a Dynamic Antiresonant Vibration Isolator (DAVI). The final flight test phase demonstrated that the DAVI-modified vehicle had substantially lower vibration levels than the standard vehicle. Vertically, the two-per-rev vibration level was reduced to less than one-fifth that of the standard vehicle through the transition speed range and less than one-half at high speeds. An R and M analysis indicated the Army could realize an annual cost savings of approximately $12,000,000 if 1000 Army UH-1Hs were equipped with DAVI isolation systems. This savings is predicated on the following assumptions: (1) vibration-induced failures will be reduced in proportion to the vibration reduction afforded by the DAVI isolation system, and (2) the UH-1Hs are utilized at the rate of 20 flight-hours per month. See also Volume 2, AD-A051 319.