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.

An actuator for aviation applications, in particular for adjusting rotor blades in a helicopter, may include an electromechanical drive assembly connected to an output drive via a downstream transmission, where the drive assembly is divided into sub-drives that can be operated independently, and where at least two sub-drives are spatially separated from one another in that the transmission is placed between these sub-drives. The transmission may include at least two harmonic gearings coupled to one another by at least one first coupling element, where a first harmonic gearing is located inside a non-rotating first housing, where a second harmonic gearing is located inside a rotating second housing, and where the second housing is connected to the output drive.

Example flap actuation systems and related methods are disclosed herein. An example control surface actuation system includes processor circuitry to cause a first actuator to generate an output to operatively couple the first actuator to a first drive arm; cause a second actuator to generate an output to operatively couple the second actuator to a second drive arm; cause the first actuator and the second actuator to move a control surface when the first actuator and the second actuator are in an operative state; detect the first actuator as in a failed state; and in response to the first actuator being in the failed state, cause first actuator to refrain from generating the output to disrupt the operative coupling between the first actuator and the first drive arm; and cause the second actuator to move the control surface via the first drive arm and the second drive arm.

An actuator for a rotor blade adjustment having an electromechanical drive unit may be connected with an output drive via a gearbox. The drive unit may have at least two partial drives that can be operated independently from one another. The gearbox may be located at least partially between the at least two partial drives such that the at least two partial drives are spaced apart from one another.

An actuator for a flight control surface of an aircraft, including: a fixed annulus for fixing to the fuselage, an rotatable annulus with respect to the fixed annulus about an axis of rotation, an output ring which can be fixed to the control surface, and a coupling mechanism having a disc with translational mobility with respect to the mobile annulus in a direction parallel to the axis of rotation, the disc able to move between an engaged position, and a disengaged position, in which the disc is disengaged from the mobile annulus to disconnect the output ring from the mobile annulus. A retaining piece keeps the disc in the engaged position, and a rupture member activates to break the retaining piece to allow the disc to move into the disengaged position.

An actuator system comprising a shared link arranged to pivot about a first axis relative to a reference structure, a controlled element arranged to pivot about a second axis relative to the reference structure, a first member arranged to pivot about a third axis relative to the shared link and a fourth axis relative to the controlled member, a first actuator arranged to control a first variable distance between the third axis and fourth axis, a second member arranged to pivot about a fifth axis relative to the shared link and a sixth axis relative to the controlled element, a second actuator arranged to control a second variable distance between the fifth axis and the sixth axis, the system configured such that a change in the first variable distance causes rotation of the controlled element about the second axis when the second variable distance is constant and vice versa.

A failsafe electro-mechanical actuator, the actuator having: an output shaft having a first and second ends spaced apart from each other along a shaft axis, and outwardly facing helical grooves formed along the first end; a motor shaft surrounding the output shaft; a harmonic drive between the motor and output shafts that transfers motion between these shafts in a first mode of operation; ball bearings seated at the first end of the motor shaft and project inwardly from the motor shaft; in the first mode of operation: the ball bearings are disengaged from the output shaft and the output shaft rotates with the motor shaft, and in a second mode of operation, the motor shaft axially moves toward the first end of the output shaft; the motor shaft is rotationally fixed; and the ball bearings engage the helical grooves in the output shaft, whereby the output shaft rotates.

In an example, a system includes a first controller for controlling a first-flight-control surface, a second controller for controlling a second-flight-control surface, and a first override system including a mechanical linkage between the first controller and the second controller. The first override system is configured such that: (i) while less than a first threshold amount of force is applied to the mechanical linkage, movement of the first controller causes a corresponding movement of the second controller and vice versa, and (ii) while greater than the first threshold amount of force is applied to the mechanical linkage, the first controller and the second controller move separately. The system also includes a second override system operable to permanently disconnect the mechanical linkage responsive to greater than a second threshold amount of force applied to the mechanical linkage. The second threshold amount of force is greater than the first threshold amount of force.

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 lower attachment system for a trimmable horizontal stabilizer actuator (THSA) includes a screwshaft forming a part of or coupled to a main screw of the actuator, the screwshaft having an axial direction and a primary ballnut disposed on the screwshaft and forming a part of a primary load path of the lower attachment system. The THSA also includes a lower secondary nut and an upper secondary nut as well as a secondary connection arranged for axial and rotational movement and coupled to each of the lower secondary nut and the upper secondary nut. The secondary connection is arranged to be loaded when the secondary load path is loaded and the secondary load path also includes the upper and lower secondary nuts.