PASSIVE HELICOPTER ROTOR ISOLATION USING THE KAMAN DYNAMIC ANTIRESONANT VIBRATION ISOLATOR (DAVI)
KAMAN AIRCRAFT CORP BLOOMFIELD CT
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The report contains the analysis and results of a study to determine the feasibility of rotor isolation employing the Dynamic Antiresonant Vibration Isolator DAVI. The theoretical analysis was conducted employing a two- dimensional DAVI for lateral and vertical isolation with conventional isolation in the longitudinal direction. Steady-state and transient inputs were analyzed. The steady-state analysis includes all six degrees of freedom of the upper body and of the lower isolated body of the helicopter. Statistical data and excitation criteria were established to study the effects and determine the feasibility of rotor isolation for a range of statistical aircraft ranging from 2000 pounds to 100,000 pounds. Also discussed are the effects of rotor isolation on control motions, crash loads, mechanical instability, and system reliability. Results of the feasibility study show that rotor isolation employing the DAVI is feasible. Isolation is feasible at the predominant frequency Nrev and all its multiples up to 4Nrev. Low static deflection at a minimum weight penalty are some of the features of the DAVI system.