Abstract: One embodiment includes a rotary aircraft, including: a main drive rotor; an aircraft body mechanically coupled to the main drive rotor; and first and second flight assist wings passively rotatably coupled to the aircraft body.

Abstract: An aircraft includes a fuselage airframe and a wing airframe that is subject to flight loads. The fuselage airframe includes fore/aft floor beams having a plurality of floor intercostals laterally extending therebetween and fore/aft roof beams with a plurality of roof intercostals laterally extending therebetween. Each of a plurality of cabin frames extends generally vertically between respective floor and roof beams. The wing airframe includes forward and aft wing spars with a plurality of wing ribs extending therebetween. At least one fuel tank, that is configured to contain a pressurized fuel such as pressurized hydrogen fuel, integrally forms at least a portion of one of the beams, the intercostals, the frames, the spars and/or the ribs such that the fuel tank is subject to the flight loads.

Abstract: A rotorcraft has a horizontal stabilizer movable about an axis of rotation and a horizontal stabilizer control system configured to control the horizontal stabilizer to at least one of move the rotorcraft into a minimum drag position, maintain the aircraft in a minimum drag position, efficiently achieve a maneuver, enter efficient autorotation, and maintain efficient autorotation.

Abstract: A rotorcraft having pusher propeller generated power during autorotations. The rotorcraft has an engine powered mode and an autorotation mode. The rotorcraft includes an engine and a drivetrain configured to receive torque and rotational energy from the engine in the engine powered mode. A main rotor system is coupled to the drivetrain and is rotatable to generate lift and forward thrust for the rotorcraft in the engine powered mode. A pusher propeller is coupled to the drivetrain and is rotatable to generate forward thrust for the rotorcraft in the engine powered mode. In the autorotation mode, the pusher propeller is aerodynamically driven responsive to airflow therethrough and the drivetrain is configured to receive torque and rotational energy from the pusher propeller, thereby providing power to the main rotor system.

Abstract: A rotor system for a rotorcraft includes a rotor hub having a plurality of blade grips coupled thereto. Each blade grip has a rotor blade coupled thereto. A fairing is disposed at least partially around the rotor hub. Each of a plurality of lead-lag dampers is coupled to at least a respective one of the blade grips. Each lead-lag damper has a damper heat exchanger and a fluid pump operably associated therewith. A fairing heat exchanger is in fluid communication with the damper heat exchangers and the fluid pumps. Each lead-lag damper is configured to drive the respective fluid pump responsive to damping operations to pump a cooling fluid from the respective damper heat exchanger to the fairing heat exchanger.

Abstract: A method of simulating an aircraft one-engine inoperative (“OEI”) event includes operating a supplemental power unit (“SPU”) at a first SPU power level less than an SPU contingency power rating, operating a primary engine at a first primary-engine power level, reducing the primary-engine power level to less than the first primary-engine power level, and maintaining a sum of the primary-engine power level and the SPU power level at a power level substantially equal to the SPU contingency power rating.

Abstract: An aircraft includes a fuselage airframe and a wing airframe that is subject to flight loads. The fuselage airframe includes fore/aft floor beams having a plurality of floor intercostals laterally extending therebetween and fore/aft roof beams with a plurality of roof intercostals laterally extending therebetween. Each of a plurality of cabin frames extends generally vertically between respective floor and roof beams. The wing airframe includes forward and aft wing spars with a plurality of wing ribs extending therebetween. At least one fuel tank, that is configured to contain a pressurized fuel such as pressurized hydrogen fuel, integrally forms at least a portion of one of the beams, the intercostals, the frames, the spars and/or the ribs such that the fuel tank is subject to the flight loads.

Abstract: An exemplary electric distributed propulsion system includes two or more rotors that are individually controlled by the rotational speed of associated motors, an input control connected to the associated motors to provide rotational speed control to the two or more rotors to produce a desired net thrust, and a logic connected to the input control and the associated motors, the logic for controlling speed and direction of the two or more rotors to achieve the desired net thrust and to avoid a motor speed condition.

Abstract: A rotor system for a rotorcraft includes a rotor hub having a plurality of blade grips coupled thereto. Each blade grip has a rotor blade coupled thereto. A fairing is disposed at least partially around the rotor hub. Each of a plurality of lead-lag dampers is coupled to at least a respective one of the blade grips. Each lead-lag damper has a damper heat exchanger and a fluid pump operably associated therewith. A fairing heat exchanger is in fluid communication with the damper heat exchangers and the fluid pumps. Each lead-lag damper is configured to drive the respective fluid pump responsive to damping operations to pump a cooling fluid from the respective damper heat exchanger to the fairing heat exchanger.

Abstract: A rotor system includes a drive hub, a set of rotor blades extending radially from the drive hub, and a set of tension-torsion straps connecting the rotor blades to the drive hub. The drive hub has a rotor mast opening extending along a mast axis. The rotor system is configured to rotate about the mast axis. The drive hub further has a set of mounting slots for mounting the tension-torsion straps. The mounting slots are arranged along a circle around the drive hub, each mounting slot extending through the drive hub along a respective mounting axis. The mounting axis of each of the mounting slots is biased relative to the mast axis. The tension-torsion straps are mounted to the drive hub at their corresponding mounting slots.

Abstract: An exemplary anti-torque system for a helicopter includes two or more electric fans rotatably mounted on a tail boom, the two or more electric fans rotatable about a longitudinal axis of the tail boom.

Abstract: Systems and methods include providing an aircraft with a ducted rotor assembly. The ducted rotor assembly includes a housing having a duct, a rotor drive mechanism coupled to a rotor system, and a plurality of stators that both structurally support the rotor drive mechanism within the duct of the housing and carry a fluid through internal fluid passages in the plurality of stators to provide cooling to the rotor drive mechanism. Some of the stators carry fluid to the rotor drive mechanism, where the fluid absorbs heat from the rotor drive mechanism, and some of the stators carry fluid away from the rotor drive mechanism. The rotor system generates an airflow over the stators carrying fluid away from the rotor drive mechanism to effect transfer between the fluid and the airflow.

Abstract: One embodiment includes a rotary aircraft, including: a main drive rotor; an aircraft body mechanically coupled to the main drive rotor; and first and second flight assist wings passively rotatably coupled to the aircraft body.

Abstract: A method of controlling a tail rotor system includes pivoting a swashplate of the tail rotor system about an axis passing through a diameter of the swashplate. Pivoting the swashplate causes a first linkage of a first pair of linkages coupled between the swashplate and a collective crosshead to move in a first direction and a second linkage of the first pair of linkages coupled between the swashplate and the collective crosshead to move in a second direction that is opposite the first direction. The movement of the first and second linkages causes a plane of rotation of a pair of rotors of the tail rotor system to cant relative to a centerline of a mast of the tail rotor system. A tail rotor system is also disclosed.

Abstract: An aircraft having an electric motor coupled to a rotor and an instrument electronically connected to the electric motor and configured to communicate a time available value before a motor condition reaches a motor condition limit.

Abstract: Systems and methods include providing an aircraft with a vertical stabilizer system having a vertical stabilizer operatively coupled to a tail boom, tail rotor gearbox, or other component of the aircraft at a forward attachment and an aft attachment. The vertical stabilizer is selectively rotatable to adjust an angle of attack of the vertical stabilizer with respect to a forward flight direction of the aircraft. The vertical stabilizer is rotatable between a forward flight position having a substantially small degree angle of attack and a hover or lateral movement position having a substantially ninety degree angle of attack.

Abstract: A rotorcraft having pusher propeller generated power during autorotations. The rotorcraft has an engine powered mode and an autorotation mode. The rotorcraft includes an engine and a drivetrain configured to receive torque and rotational energy from the engine in the engine powered mode. A main rotor system is coupled to the drivetrain and is rotatable to generate lift and forward thrust for the rotorcraft in the engine powered mode. A pusher propeller is coupled to the drivetrain and is rotatable to generate forward thrust for the rotorcraft in the engine powered mode. In the autorotation mode, the pusher propeller is aerodynamically driven responsive to airflow therethrough and the drivetrain is configured to receive torque and rotational energy from the pusher propeller, thereby providing power to the main rotor system.

Abstract: A rotorcraft has a horizontal stabilizer movable about an axis of rotation and a horizontal stabilizer control system configured to control the horizontal stabilizer to at least one of move the rotorcraft into a minimum drag position, maintain the aircraft in a minimum drag position, efficiently achieve a maneuver, enter efficient autorotation, and maintain efficient autorotation.

Abstract: A transmission tilt control device includes a transmission rotatably coupled to an airframe of a helicopter, a rotor mast coupled to the transmission, and an actuator coupled between the transmission and the airframe. The actuator being configured to rotate the transmission fore and aft about a tilt axis that is perpendicular to an axis of rotation of the rotor mast.

Abstract: An aircraft having an electric motor coupled to a rotor and an instrument electronically connected to the electric motor and configured to communicate a time available value before a motor condition reaches a motor condition limit.