A method of reducing the noise generated in-flight by a vortex wake caused by each first blade of a main rotor of a hybrid helicopter. The hybrid helicopter includes a main rotor, at least two wings and at least one propeller. The method enables a stabilized flight phase on the level or with a non-zero aerodynamic slope to be implemented by determining a first value of the pitch of the second blades of each propeller and an angle of incidence of the main rotor as function of the flight conditions, then by applying the first pitch value to each propeller and by applying the angle of incidence to the main rotor so as to direct the vortex wake to limit the noisy interactions between the vortex wake and the other first blades and/or the second blades.

A method of reducing the noise generated in-flight by a vortex wake caused by each first blade of a main rotor of a hybrid helicopter. The hybrid helicopter includes a main rotor, at least two wings and at least one propeller. The method enables a stabilized flight phase on the level or with a non-zero aerodynamic slope to be implemented by determining a first value of the pitch of the second blades of each propeller and an angle of incidence of the main rotor as function of the flight conditions, then by applying the first pitch value to each propeller and by applying the angle of incidence to the main rotor so as to direct the vortex wake to limit the noisy interactions between the vortex wake and the other first blades and/or the second blades.

A compound rotorcraft comprises a fuselage, a rotor coupled to the fuselage and a wing mounted to the fuselage. The rotorcraft further comprising a first outboard propeller, a first inboard propeller, a second outboard propeller, and a second inboard propeller. The first outboard propeller having a propeller body and propeller blades, the body mounted to a first wing-half at a first incidence angle. The first inboard propeller having a propeller body and propeller blades, the body mounted to the first wing-half between the first outboard propeller and the fuselage at a second incidence angle. The second outboard propeller having a propeller body and propeller blades, the body mounted to a second wing-half at a third incidence angle. The second inboard propeller comprising a propeller body and propeller blades, the body mounted to a second wing-half between the second outboard propeller in the fuselage at a fourth incidence angle.

A compound rotorcraft comprises a fuselage, a rotor coupled to the fuselage and a wing mounted to the fuselage. The rotorcraft further comprising a first outboard propeller, a first inboard propeller, a second outboard propeller, and a second inboard propeller. The first outboard propeller having a propeller body and propeller blades, the body mounted to a first wing-half at a first incidence angle. The first inboard propeller having a propeller body and propeller blades, the body mounted to the first wing-half between the first outboard propeller and the fuselage at a second incidence angle. The second outboard propeller having a propeller body and propeller blades, the body mounted to a second wing-half at a third incidence angle. The second inboard propeller comprising a propeller body and propeller blades, the body mounted to a second wing-half between the second outboard propeller in the fuselage at a fourth incidence angle.

Vertical takeoff and landing (VTOL) aircraft are provided with fixed-position port and starboard wings extending laterally from an elongate fuselage having an empennage at an aft end of the fuselage and a propeller to provide horizontal thrust to the aircraft in a direction of the longitudinal axis thereof. A series of port and starboard rotor units are provided, each of which includes axially opposed rotor blades, and a motor to rotate the rotor blades and provide vertical thrust to the aircraft. A logic control unit (LCU) controllably sets an angular position of the opposed rotor blades along a position axis relative to the longitudinal axis of the aircraft in response to determining an optimal position of the rotor blades during cruise flight operation to thereby minimize airflow disruption over the fixed-position wings.

Vertical takeoff and landing (VTOL) aircraft are provided with fixed-position port and starboard wings extending laterally from an elongate fuselage having an empennage at an aft end of the fuselage and a propeller to provide horizontal thrust to the aircraft in a direction of the longitudinal axis thereof. A series of port and starboard rotor units are provided, each of which includes axially opposed rotor blades, and a motor to rotate the rotor blades and provide vertical thrust to the aircraft. A logic control unit (LCU) controllably sets an angular position of the opposed rotor blades along a position axis relative to the longitudinal axis of the aircraft in response to determining an optimal position of the rotor blades during cruise flight operation to thereby minimize airflow disruption over the fixed-position wings.

A VTOL fixed wing aircraft capable of high-speed forward flight. The aircraft has a main wing internally reinforced with front and aft spars. Spar boxed are located in roll-balanced locations along the wing. Each spar box serves as a connection point for a support linkage that supports a leading-edge and trailing-edge propulsion units. The leading-edge propulsion unit is fitted with a puller propeller and designed for articulated movement between a VTOL position in front of the wing leading edge and a forward flight position below the wing leading edge. The trailing-edge propulsion unit is fitted with a pusher propeller and designed for articulated movement between a VTOL position in behind the wing trailing edge and a forward flight position above the wing leading edge. The propeller includes a propulsor thrust ring having an aerodynamic profile and a thrust nozzle to capture and vector radial air leakage into thrust.

A rotorcraft, and, more particularly, to a rotorcraft with a fuselage having a center line, at least one main rotor that generates vortices during operation, and a stabilizer wing, whereby the stabilizer wing has a planform that reduces the unsteady aerodynamic loads caused by the wake of the at least one main rotor. In particular, the stabilizer wing may be provided with a left wing tip, a right wing tip, a quarter chord line with a non-zero curvature, such that an interaction between the vortices generated by the at least one main rotor and the quarter chord line is spread out over time, a leading edge that is arc-shaped, and a trailing edge that is arc-shaped.

A rotorcraft, and, more particularly, to a rotorcraft with a fuselage having a center line, at least one main rotor that generates vortices during operation, and a stabilizer wing, whereby the stabilizer wing has a planform that reduces the unsteady aerodynamic loads caused by the wake of the at least one main rotor. In particular, the stabilizer wing may be provided with a left wing tip, a right wing tip, a quarter chord line with a non-zero curvature, such that an interaction between the vortices generated by the at least one main rotor and the quarter chord line is spread out over time, a leading edge that is arc-shaped, and a trailing edge that is arc-shaped.

Vertical take-off and landing (VTOL) aircraft can provide opportunities to incorporate aerial transportation into transportation networks for cities and metropolitan areas. However, VTOL aircraft may be noisy. To accommodate this, the aircraft may utilize onboard sensors, offboard sensing, network, and predictive temporal data for noise signature mitigation. By building a composite understanding of real data offboard the aircraft, the aircraft can make adjustments to the way it is flying and verify this against a predicted noise signature (via computational methods) to reduce environmental impact. This might be realized via a change in translative speed, propeller speed, or choices in propulsor usage (e.g., a quiet propulsor vs. a high thrust, noisier propulsor). These noise mitigation actions may also be decided at the network level rather than the vehicle level to balance concerns across a city and relieve computing constraints on the aircraft.