An aeroelastic analysis of bearingless rotor systems with trailing edge flaps was conducted using large deflection-type beam theory for forward flight conditions with a focus on reducing vibration while minimizing control effort.The aerodynamic forces of the rotor blade were calculated using two-dimensional quasi-steady strip theory.For the analysis of forward flight, the nonlinear periodic blade steady response was obtained by integrating the full finite element equation in time through a coupled trim procedure with a vehicle trim.The objective function, which includes vibratory hub loads and active flap control inputs, was minimized by an optimal control process.