A rotor blade of a rotary wing aircraft includes a core defining a trailing edge of the rotor blade and a skin extending from the trailing edge defining an opening including the core. The skin defines an aerodynamic surface of the rotor blade. The rotor blade additionally includes at least one trim tab assembly including a trim portion extending from the core beyond the trailing edge of the rotor blade and an actuation system including at least one actuator disposed within the core. The actuation system is operable to adjust an angle of the trim portion relative to the rotor blade.

A linear actuator is provided. The linear actuator comprises: a body; a shaft adapted to move linearly relative to the body; a driver adapted to drive the linear movement of the shaft; and a shape memory alloy component configured to compensate for thermal expansion or contraction of the linear actuator due to a change in temperature thereof.

According to one embodiment, a noise reduction device includes speakers, microphones, and a processing circuit. The speakers are arranged around a rotor and emit control sound based on control signals. The microphones are arranged around the rotor and convert the control sound and noise emitted by the rotor into microphone signals. The processing circuit generates the control signals for reducing acoustic power in positions of the microphones, based on the microphone signals, rotation speed of the rotor, and a phase of noise that reaches the microphones from the rotor.

A gurney flap arrangement includes: an airfoil 2 with a trailing edge 6 and an opening 14 in a surface 8 of the airfoil 2; a gurney flap 1 having a first position in which at least a portion of the gurney flap 1 extends through the opening 14 and projects outwardly from the airfoil surface 8, and a second position in which the gurney flap 1 does not project from the airfoil surface 8 or projects outwardly from the airfoil surface 8 to a lesser extent; and a gurney flap actuator 3 for moving the gurney flap 1 between at least the first position and the second position.

A locking device for use in a rotor blade, said locking device comprising: a locking member that is arranged to be movable from an unlocked position to a locking position upon experiencing sufficiently fast rotation; and a selectively engagable retaining device arranged when engaged to retain the locking member in the unlocked position. The locking device will typically default to an unlocked position during normal rotation and will only be locked so as to prevent movement when the retaining device is de-activated. A method of locking an actuator is also disclosed. The locking device has applications in helicopter rotor blades and wind turbine blades amongst others.

Actuators are components of machines, which move and/or control a mechanism or system. During operation, actuators can experience regeneration events, with the actuator actually generating excess energy (e.g., regenerative energy) which must be stored or dissipated to avoid damaging the power supply. An actuator motor controller is configured to implement field oriented voltage control and flux weakening voltage control without current sensors. Dissipating regenerative energy includes providing a motor controller to command a motor drive to modify an input voltage, or to dissipate regenerative energy in a dump circuit. This command can cause motor windings to dissipate regenerative energy. Systems having a plurality of actuators distribute regenerative energy from one actuator to another. A central controller provides centralized regeneration dissipation control for the plurality of actuators. A power distribution unit includes a dump resistor to dissipate regenerative energy in addition to or instead of in the actuators.

A blade of a rotor for a rotary-wing aircraft is equipped with an outer covering extending along the span of the blade. This outer covering is provided with an extrados skin and with an intrados skin defining a cavity. The blade also includes a structure that extends into the cavity and connects the blade to a hub of the rotor. The cavity is filled with a filling material that includes at least one partition parallel to a chord of the blade and at least two independent blocks of filling material filling the cavity, thereby allowing the reduction of the torsional rigidity along the span of the blade.

A main rotor trim tab retention system includes, a blade housing having flanges separated by a cavity defined between the flanges, and a trim tab assembly. The trim tab assembly includes, a trim tab having an aerodynamic surface, at least one arm extending from the trim tab positionable within the cavity while the trim tab extends outward from the cavity, and a spherical bearing connecting the trim tab and the at least one arm, the spherical bearing having a first axis which is substantially perpendicular to the aerodynamic surface of the trim tab. The at least one arm is pivotable about the spherical bearing about a second axis substantially perpendicular to the first axis to rotate the trim tab relative to the blade housing.

A propelling system with variable aerodynamic controls is a system used to generate and control the flight forces of an aircraft. The system includes a stator, a rotor, a plurality of propelling units, and a control system. The stator serves as the stationary connection to the aircraft. The rotor revolves the propelling units about a central rotation axis. The control system enables the control of the propelling units. The propelling units generate the flight forces for the aircraft in the desired direction. In addition, each of the propelling units include a blade body, a shaft channel, a spar shaft, and at least one aileron assembly. The shaft channel receives the spar shaft within the blade body. The spar shaft connects the blade body to the rotor. The blade body passively corrects its angle of attack and supports the aileron assembly. The aileron assembly adjusts the pitch of the blade body.

A blade for an aircraft rotor has a trailing-edge tab, the tab being movable between a stowed position, in which substantially all of the tab is located within the blade, and a deployed position, in which at least a portion of the tab extends from a trailing edge of the blade. At least one actuator system is selectively operable to cause movement of the tab between the stowed position and the deployed position for changing a chord length of the blade.