High Stiffness (“Rigid”) Helicopter Pylon Vibration Isolation Systems

Rotor loads occurring at N/rev are a primary source of vibration in helicopters. Helicopter pylon isolation systems have evolved into tuned anti-resonant systems with performance optimized for the N/rev frequency. Tuned isolators using fluid inertia have been demonstrated to be effective, compact and practical in production applications. Higher stiffness systems have been developed to allow retrofit to helicopters with “rigid” structure that did not provide for vibration isolators in the original design. Dynamic analysis has shown that even high stiffness tuned isolators can provide improved vibration isolation. A prototype Fluidlastic® isolator for a 10-ton helicopter has been designed and tested. Test results have confirmed that it meets dynamic performance goals. Active augmentation of Fluidlastic® tuned isolators offers potential for further reduction of vibration.