A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region and that comprises a fuselage with a front section and a rear section, the rotary wing aircraft comprising: a main rotor that is rotatably mounted at the front section, a shrouded duct that is arranged in the aft region, and a propeller that is rotatably mounted to the shrouded duct, wherein the rear section extends between the front section and the shrouded duct and comprises an asymmetrical cross-sectional profile in direction of the associated roll axis.

A method for controlling a hybrid helicopter having at least one lifting rotor, at least one forward-movement propeller and an empennage provided with at least one moveable empennage surface. The method includes the following steps: using a main sensor to determine a current value of a rotor parameter conditioning a current power drawn by the lifting rotor, using an estimator to determine a current setpoint of the rotor parameter, adjusting a position of the moveable empennage surface using a deflection controller as a function of the current value and of current setpoint.

An aircraft includes a main body having an empennage, a main rotor assembly mounted on the main body, and a movable control surface assembly supported on the empennage. The movable control surface assembly includes a tube extending from the empennage along a tube axis to a free end, the tube being supported for rotation about the tube axis with respect to the empennage, and a movable control surface mounted on the tube for rotation therewith. The movable control surface is supported on the tube by a connection element that couples the movable control surface to the free end of the tube to rotatably fix the movable control surface with respect to the tube.

A propulsion system for a rotorcraft includes a first fan assembly including a plurality of first fan blades, a second fan assembly including a plurality of second fan blades and a drive system adapted to provide torque to the first and second fan blades. The first fan blades have a larger rotational inertia than the second fan blades. The second fan blades are adapted to experience a larger angular acceleration than the first fan blades in response to torque from the drive system, thereby providing responsive thrust control for the rotorcraft.

Tail boom drive systems for helicopters are described which utilize a fan internal to the tail boom to provide yaw control, and an external propulsor to provide forward thrust. In one embodiment, the tail boom drive system includes a shaft, a fan, and a propulsor. The shaft is disposed lengthwise within an interior space of the tail boom, and the shaft has a first end and a second end. The fan is mechanically coupled coaxially to the shaft within the interior space between the first end and the second end, and the fan generates a variable airflow directed towards the second end that is ejected from the interior space substantially perpendicular to the tail boom. The propulsor is external to the tail boom and is mechanically coupled coaxially to the shaft at the second end, and the propulsor generates a variable thrust directed towards the first end.

A rotary wing vehicle includes a body structure having an elongated tubular backbone or core, and a counter-rotating coaxial rotor system having rotors with each rotor having a separate motor to drive the rotors about a common rotor axis of rotation. The rotor system is used to move the rotary wing vehicle in directional flight.

Embodiments are directed to a rotorcraft comprising a body having a longitudinal axis, a wing coupled to the body, a single tiltrotor assembly pivotally coupled to the body, and the tiltrotor assembly configured to move between a position generally perpendicular to the longitudinal axis during a vertical flight mode and a position generally parallel to the longitudinal axis during a horizontal flight mode. The rotorcraft may further comprise an anti-torque system configured to counteract torque generated by the tiltrotor assembly during vertical flight. The rotorcraft may further comprise a center of gravity compensation system configured to manage a rotorcraft center of gravity during movement of the tiltrotor assembly between the vertical flight mode and the horizontal flight mode.

An advancing blade concept rotorcraft includes an airframe and a pylon assembly subject to vibration. The pylon assembly includes a dual rotor system having coaxially disposed top and bottom rotor assemblies that counter rotate relative to one another. The advancing blade concept rotorcraft includes a vibration isolation system including at least one pylon link coupled to the airframe and the pylon assembly. The pylon link includes a Liquid Inertia Vibration Eliminator unit operable to reduce transmission of the pylon assembly vibration to the airframe. The advancing blade concept rotorcraft includes active force generators adjacent to the pylon assembly. The active force generators include a first active force generator producing a force in a first direction and a second active force generator producing a force in a second direction to counteract multidirectional oscillations of the pylon assembly, thereby reducing vibration of the advancing blade concept rotorcraft.

A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region and that comprises a fuselage with a front section and a rear section, the rotary wing aircraft comprising: a main rotor that is rotatably mounted at the front section, a shrouded duct that is arranged in the aft region, and a propeller that is rotatably mounted to the shrouded duct, wherein the rear section extends between the front section and the shrouded duct and comprises an asymmetrical cross-sectional profile in direction of the associated roll axis.

A rotor blade retention assembly includes a central hub, a rotor blade including an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub, a strap member extending along a portion of the rotor blade such that a distal end receiving portion extends into the blade hole, and a retainer assembly disposed within the blade hole and coupled to the strap member. The retainer assembly includes an upper bushing and a lower bushing slidably disposed within the blade hole. The upper bushing includes a counterbored portion. The retainer assembly also includes an outboard blade pin disposed within the distal end receiving portion and includes a blade pin inner cavity.