According to some embodiments, a rotorcraft includes a secondary rotor control system located proximate to the empennage of the rotorcraft. The secondary rotor control system includes at least one hydraulic pump and at least one hydraulic actuator. The at least one hydraulic pump is located proximate to the empennage. The at least one hydraulic actuator is located proximate to the empennage and configured to adjust at least one operating characteristic of the at least one secondary rotor blade.

Disclosed herein is an exemplary embodiment of a system for driving a slat of an aircraft. The system includes first and second hinge support elements of a wing structure, a first arm device, a second arm device, and a third arm device. Also disclosed is an aircraft having the system, an aircraft wing having the system, and a method for driving a slat of an aircraft. The system utilizes a particular configuration of connection junctions, which rotatably connect the arm devices and the hinge support elements.

Disclosed herein is an exemplary embodiment of a system for driving a slat of an aircraft. The system includes first and second hinge support elements of a wing structure, a first arm device, a second arm device, and a third arm device. Also disclosed is an aircraft having the system, an aircraft wing having the system, and a method for driving a slat of an aircraft. The system utilizes a particular configuration of connection junctions, which rotatably connect the arm devices and the hinge support elements.

According to one embodiment, a method for determining a position of a rotor blade includes receiving a plurality of measurements from a plurality of magneto-resistive sensors and determining a position of the at least one magnet based on the received plurality of measurements. In this example, one of the plurality of magneto-resistive sensors and the at least one magnet moves with a rotor blade.

An anti-torque rotor of a helicopter, having: a supporting body; a drive shaft which rotates about a first axis with respect to the supporting body; a hub connected operatively to drive shaft and angularly fixed with respect to first axis; at least one blade which is connected operatively to hub, is angularly fixed with respect to first axis, and is angularly movable with respect to a second axis to adjust the pitch angle of blade; and an actuator which can be operated to rotate blade about second axis to adjust the pitch angle of blade; actuator has an electric motor which generates torque along the first axis; and a mechanical stage interposed between the electric motor and blade, and designed to convert the torque into rotation of blade about the respective second axes; electric motor is fixed to supporting body.

A bearing system includes an inboard bearing assembly and an outboard bearing assembly. The inboard bearing assembly includes an inboard fitting and an inboard race. The inboard fitting includes a plate with a convex mating surface and a first aperture formed through the plate for receiving a blade root of a rotor blade. The inboard race comprising a concave mating surface configured to receive the convex mating surface a second aperture formed the inboard race. The outboard bearing assembly includes an outboard bearing assembly comprising an outboard fitting having an aperture formed therethrough for receiving the blade root of the rotor blade.

A bearing system includes an inboard bearing assembly and an outboard bearing assembly. The inboard bearing assembly includes an inboard fitting and an inboard race. The inboard fitting includes a plate with a convex mating surface and a first aperture formed through the plate for receiving a blade root of a rotor blade. The inboard race comprising a concave mating surface configured to receive the convex mating surface a second aperture formed the inboard race. The outboard bearing assembly includes an outboard bearing assembly comprising an outboard fitting having an aperture formed therethrough for receiving the blade root of the rotor blade.

A compound helicopter includes a fuselage including a fuselage airframe, a translational thrust system coupled to the fuselage airframe and a pylon assembly subject to vibration. The pylon assembly includes a transmission and a rotor system having a main rotor assembly. The compound helicopter also includes a main rotor vibration isolation system including a plurality of augmented liquid inertia vibration eliminator units each having an isolation frequency and each coupled between the fuselage airframe and the pylon assembly to reduce transmission of the pylon assembly vibration to the fuselage airframe at the isolation frequency. Each augmented liquid inertia vibration eliminator unit includes at least one active tuning element movable to tune the isolation frequency thereof.

A rotor system includes a rotor assembly and a duct system. The rotor assembly includes rotor blades extending from a mast axis and configured to rotate about the mast axis. The duct assembly includes a moveable duct portion and a stationary duct portion. In a first duct configuration, the moveable duct portion surrounds a first portion of the rotor assembly, the stationary duct portion surrounds a second portion of the rotor assembly, and the moveable duct portion and the stationary duct portion enclose the rotor assembly. In a second duct configuration, the stationary duct portion surrounds the second portion of the rotor assembly, and the moveable duct portion is moved away from the first portion of the rotor assembly, such that the rotor assembly is not enclosed.

A rotor system includes a rotor assembly and a duct system. The rotor assembly includes rotor blades extending from a mast axis and configured to rotate about the mast axis. The duct assembly includes a moveable duct portion and a stationary duct portion. In a first duct configuration, the moveable duct portion surrounds a first portion of the rotor assembly, the stationary duct portion surrounds a second portion of the rotor assembly, and the moveable duct portion and the stationary duct portion enclose the rotor assembly. In a second duct configuration, the stationary duct portion surrounds the second portion of the rotor assembly, and the moveable duct portion is moved away from the first portion of the rotor assembly, such that the rotor assembly is not enclosed.