According to one embodiment, a linear control motor includes a first permanent magnet, a coil, a shaft, a first non-magnetic material, and a joint coupled between the shaft and a spool operable to convert rotations of the shaft into axial movements of the spool. The first non-magnetic material is disposed between at least one of the movable components and at least one of the static components and operable to prevent physical contact between at least one of the movable components and at least one of the static components.

According to one embodiment, a linear control motor includes a first permanent magnet, a coil, a shaft, a first non-magnetic material, and a joint coupled between the shaft and a spool operable to convert rotations of the shaft into axial movements of the spool. The first non-magnetic material is disposed between at least one of the movable components and at least one of the static components and operable to prevent physical contact between at least one of the movable components and at least one of the static components.

A servo-control having at least one movable cylinder that includes a hydraulic directional control valve. The hydraulic valve includes a control shaft that is rotatable about a longitudinal axis, the control shaft being connected to a distributor slide. The servo-control including a stationary abutment member secured to a cylinder and an input lever situated outside the cylinder. The input lever is connected to the control shaft and includes a stop portion arranged in the abutment member. The servo-control includes movement means for moving the input lever longitudinally, a first abutment surface of the abutment member limiting a travel amplitude of the stop portion when the input lever is in a first position.

The invention relates to an autogyro having a rotor (12). According to the invention, a gas pressure spring (32) is provided and is arranged for trimming the rotor (12).

The invention relates to an autogyro having a rotor (12). According to the invention, a gas pressure spring (32) is provided and is arranged for trimming the rotor (12).

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.

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.

Systems and methods include providing an aircraft with a direct drive dual-concentric valve (D3V) having a body, an outer secondary spool coaxially located within a bore of the body and linearly displaceable relative to the body, an inner primary spool coaxially located within a bore of the secondary spool and linearly displaceable relative to the secondary spool and the body. A plurality of piezo stacks is coupled to a first end of the primary spool, and applying a voltage to at least one of the piezo stacks causes an output stroke of the plurality of the piezo strokes for displacing the primary spool. The secondary spool is displaced together with the primary spool relative to the body if displacement of the primary spool relative to the secondary spool cannot occur.

A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.

A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.