A system includes an inboard tiltrotor subsystem and an outboard tiltrotor subsystem. The inboard tiltrotor subsystem includes an inboard pylon, an inboard tiltrotor, and a single and non-redundant drivetrain. The outboard tiltrotor subsystem includes an outboard pylon that is coupled to a wing and an outboard tiltrotor. The outboard tiltrotor has a range of motion and is coupled to the wing via the outboard pylon, such that the outboard tiltrotor is aft of the wing. The outboard tiltrotor subsystem further includes a redundant drivetrain (which has a plurality of motors and a plurality of motor controllers) that drives one or more blades and the one or more blades.

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.

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.

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.

Aircraft capable of vertical takeoff and landing, hovering, and efficient forward flight are described. An aircraft includes two side mounted tiltable proprotors and a central rotor disposed above the proprotors. The proprotors are tiltable between at least a horizontal position for forward flight and a vertical position for vertical or hovering flight. The central rotor may be powered for vertical and transitional flight modes and may turn by free autorotation during forward flight. The proprotors may be differentially tilted during vertical or hovering flight to counter torque effects of the central rotor. The central rotor may be foldable and/or easily detachable from the aircraft to facilitate storage and transportation. Left and right proprotors may provide both forward thrust and attitude control. Control inputs to left and right proprotors may be connected directly to an autopilot creating closed loop actuation using motor RPM feedback.

Aircraft capable of vertical takeoff and landing, hovering, and efficient forward flight are described. An aircraft includes two side mounted tiltable proprotors and a central rotor disposed above the proprotors. The proprotors are tiltable between at least a horizontal position for forward flight and a vertical position for vertical or hovering flight. The central rotor may be powered for vertical and transitional flight modes and may turn by free autorotation during forward flight. The proprotors may be differentially tilted during vertical or hovering flight to counter torque effects of the central rotor. The central rotor may be foldable and/or easily detachable from the aircraft to facilitate storage and transportation. Left and right proprotors may provide both forward thrust and attitude control. Control inputs to left and right proprotors may be connected directly to an autopilot creating closed loop actuation using motor RPM feedback.

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 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.

A device for monitoring an available thrust margin of an anti-torque member of a rotorcraft as a function of flight conditions, said rotorcraft comprising a power plant driving at least one main rotor participating at least in the lift of said rotorcraft, said anti-torque member participating in the control of the yaw movements of said rotorcraft.