Analysis of Rotorcraft Vibration Reduction Using a Center-of-Gravity Offset

When a rotorcraft has N blades, N/rev vibration becomes large as the cruise speed increases. This article numerically examines effect of Center-of-Gravity (CG) offset on vibration. A mid-sized rotorcraft, SH-60K, was selected for analysis with use CAMRAD II. minimum 60% decrease in baseline z-acceleration achieved at pilot seat, which dominantly defines circumstance CG. There exists middle CG location between and CG, where both main rotor power characteristics trim attitudes are allowable. At that point, an approximately 20% reduction seat can be achieved. Not only preexisting helicopters, but also development, engineers should keep mind positions worth investigating to reduce vibration; although, almost all have been directly below hub.