A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region. The rotary wing aircraft comprises a main rotor; a propeller that is at least configured to propel the rotary wing aircraft in forward flight condition, wherein the propeller forms a circular propeller disc in rotation around an associated rotation axis; and a shrouded duct that is arranged in the aft region and that forms an inner air duct which accommodates at least partly the propeller, wherein the shrouded duct comprises a yaw and pitch stability enhancement unit for improving yaw and pitch stability of the rotary wing aircraft in the forward flight condition.

A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region. The rotary wing aircraft comprises a main rotor; a propeller that is at least configured to propel the rotary wing aircraft in forward flight condition, wherein the propeller forms a circular propeller disc in rotation around an associated rotation axis; and a shrouded duct that is arranged in the aft region and that forms an inner air duct which accommodates at least partly the propeller, wherein the shrouded duct comprises a yaw and pitch stability enhancement unit for improving yaw and pitch stability of the rotary wing aircraft in the forward flight condition.

Embodiments include an aircraft comprising a fuselage; a wing connected to the fuselage; and first and second propulsion systems connected to the wing on opposite sides of the fuselage, wherein at least a portion of each of the first and second propulsion systems and at least a portion of the wing are tiltable between a first position in which the aircraft is in a hover mode and a second position in which the aircraft is in a cruise mode, wherein each of the propulsion systems includes pylon and a rotor assembly comprising a plurality of rotor blades.

According to one implementation, a rotating device includes at least one ring, at least one motor and a power transmission mechanism. The least one ring rotates in a circumference direction. The at least one ring includes no hub for housing a motor inside the at least one ring. The at least one motor generates power for rotating the at least one ring. The power transmission mechanism transmits the power to the at least one ring.

A rotorcraft provided with a yaw motion control system comprising a fairing and a rotor provided with blades, the blades being arranged in the fairing and able to rotate about an axis of rotation of the rotor, the fairing comprising a casing defining an air stream, the air stream extending in a direction of flow of the air within the fairing from an intake section towards an outlet section. The rotorcraft comprises an ice protection system comprising at least one grille arranged upstream of the air stream in the air flow direction, the grille facing the intake section parallel to the axis of rotation and the casing, no grille facing at least one unprotected section of the intake section in a direction parallel to the axis of rotation.

Disclosed is a rotor system for an aircraft including a rotor having multiple rotor blades disposed about an axis of rotation of the rotor substantially radially. A plane perpendicular to the axis of rotation, which extends through the rotor blades in a radial direction, forms a rotor plane. A rotor shroud surrounds the rotor circumferentially with regard to the axis of rotation, confines an air duct of the rotor extending in an axial direction of the axis of rotation, and forms a hollow structure extending circumferentially with regard to the axis of rotation. The hollow structure has on its circumferential face facing the rotor in the radial direction an area permeable to gas. The rotor plane intersects the area, and the hollow structure is configured to at least partially absorb acoustic waves of at least one frequency penetrating through the area.

A tail rotor assembly coupled to a tailboom of a helicopter includes a tail rotor gearbox having top, bottom and aft sides and a shroud surrounding the tail rotor gearbox. The shroud includes a shroud airframe having top and bottom portions. The tail rotor assembly includes a tail rotor gearbox support assembly configured to support the tail rotor gearbox within the shroud. The tail rotor gearbox support assembly includes a support column coupling the aft side of the tail rotor gearbox between the top and bottom portions of the shroud airframe, an upper support crossbar coupling the top side of the tail rotor gearbox between the support column and the tailboom airframe and a lower support crossbar coupling the bottom side of the tail rotor gearbox between the support column and the tailboom airframe.

The present invention includes an a plurality of first variable speed motors mounted on a tail boom of the helicopter; one or more fixed pitch blades attached to each of the plurality of first variable speed motors; and wherein a speed of one or more of the plurality of first variable speed motors is varied to provide an anti-torque thrust.

The invention is for a VTOL (vertical take-off and landing) rotorcraft with the annular contra-rotating rotary wings and auxiliary propulsor. The rotary wing of the annular contra-rotating rotary wings is driven by a plurality of tangential forces applied at multiple locations of the inner hub or at the tip of the blade. The annular contra-rotating rotary wings can be shrouded with a nacelle for the improvement of propulsive efficiency, reduction of noise and protection of the rotary wing. The fuselage is mounted along the center axis of the rotary to be outside of the thrust slipstream. The auxiliary propulsor includes a quad independent pusher propeller to propel the rotorcraft to reach faster forward speed.

A yaw control system for a helicopter having a tailboom includes one or more tail rotors rotatably coupled to the tailboom and a quiet mode controller. The quiet mode controller includes a noise monitoring module configured to monitor one or more flight parameters of the helicopter and a quiet mode command module configured to selectively switch the one or more tail rotors to a quiet mode based on the one or more flight parameters. The quiet mode command module is also configured to modify one or more operating parameters of the one or more tail rotors in the quiet mode to reduce noise emitted by the helicopter.