Optimal trailing-edge flaps in helicopter for vibration reduction at various peak deflections of the flaps

Helicopters are one of the most useful classes of flying vehicles because of the vertical take-off, landing and hovering capability, but suffers from severe vibration mainly from the rotor. Trailing-edge flaps are one of the successful techniques to reduce vibration in helicopter rotor. In this study, attempt is made to find an optimum Flap Peak Deflection Angle (FPDA) in reducing rotor hub vibration with minimum penalty in flap power requirement. Result show that the optimum design point at FPDA=±60 gives a vibration reduction of about 88% compared to FPDA=±20, but at the cost of increased flap power requirement.