The Model 427 uses a main rotor pylon mounting system that provides good vibration isolation while being stiff vertically and compliant in pitch and roll. The design goal during the helicopter's development was to provide low vibrations yet allow the use of maintenance-free drive shaft couplings. Due to design and frequency placement constraints, LIVE (Fluidlastic) mounts were employed. This provided a pylon design that globally eliminated most of the main rotor 4/rev vibration (94% isolation of main rotor 4/rev vertical vibration). The residual airframe vibration is locally treated with a lightweight Frahm absorber in the crew area. A description is provided of the Model 427 pylon design including design challenges, the principles of a LIVE pylon isolation system, and actual flight test verification data.
Model 427 pylon isolation system
1999
7 Seiten, 2 Quellen
Conference paper
English