Actuator design for the active trailing edge of a helicopter rotor blade

Today, helicopters still suffer from their environmental impact regarding external noise, fuel consumption and emissions, their low passenger comfort regarding cabin noise and vibrations and their limited performance regarding flight envelope, speed and range. One of the main sources of noise and vibrations is the main rotor, especially in fast forward and descent flight. Therefore, technologies for advanced rotor control are investigated. Individual blade control (IBC) systems allow to reduce vibration, noise and shaft power consumption. To control each rotor blade individually, on-blade actuation mechanisms based on active materials offer advantages in weight, power consumption and bandwidth compared to systems actuating the rotor blade root. The most advanced approaches so far are the direct twist concept and the trailing edge flap. The topic of this paper is a new concept for an IBC actuator the Active Trailing Edge. The Active Trailing Edge concept realizes a morphing cross section for a helicopter rotor blade. The trailing edge of the airfoil is able to deflect upwards and downwards. Similar to the trailing edge flaps, the ATE aims to twist the blade aeroelastically using the servo effect, i.e. the change in aerodynamic pitching moment twists the rotor blade.