Helicopter uses a rotor system to generate lift, thrust and forces, and its aerodynamic environment is generally complex.
Unsteady aerodynamic environment arises such as blade vortex interaction. This unsteady aerodynamic environment
induces vibratory aerodynamic loads and high aeroacoustic noise. The aerodynamic load and aeroacoustic noise is at N
times the rotor blade revolutions (N/rev). But conventional rotor control system composed of pitch links and swash plate
is not capable of adjusting such vibratory loads because its control is restricted to 1/rev. Many active control
methodologies have been examined to alleviate the problem. The blade using active control device manipulates the
blade pitch angle with N/rev. In this paper, Active Trailing-edge Flap blade, which is one of the active control methods,
is designed to reduce the unsteady aerodynamic loads. Active Trailing-edge Flap blade uses a trailing edge flap
manipulated by an actuator to change camber line of the airfoil. Piezoelectric actuators are installed inside the blade to
manipulate the trailing edge flap.