An anti-torque rotor is described for a helicopter, comprising: a mast rotatable about a first axis; a plurality of blades hinged on the mast, extending along respective second axes transversal to said first axis and rotatable about respective said second axes to alter the respective angles of attack; a control element sliding and rotating with respect to the mast, and operatively connected to said blades to cause the rotation of said blades about respective second axes following a translation of said element along the first axis; a control rod sliding axially along first axis with respect to the mast and angularly fixed with respect to the first axis; and a bearing interposed between the control rod and the control element, sliding along the first axis with respect to the mast and integrally with the control rod; the anti-torque rotor further comprises an interface made of an antifriction material interposed between said control rod and said bearing.

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.

A flexible coupling includes a first flange having an outer edge, a first surface, a second surface opposite the first surface, and a first plurality of passages. A second flange including an outer edge section, a first surface section, a second surface section opposite the first surface section, and a second plurality of passages. A connecting element extends between and connecting the first flange and the second flange through one of the first plurality of passages and one of the second plurality passages. The connecting element includes a connecting member having a first stop element and a second stop element. A compliant component is arranged on the connecting element. The compliant component is positioned on the connecting member between one of: the first stop element and the first surface; the second stop element and the second surface section; and between the second surface and the first surface section.

A pitch change link may include a shaft having a first end region and a second end region, and a bearing cartridge on at least one of the first end region and the second end region. The bearing cartridge may include a bearing and a bearing ring at least partially surrounding the bearing. The bearing ring may have a geometric symmetry and a cross section that is wider at a first end than at a second end, the first end may oppose the second end.

A pitch change link may include a shaft having a first end region and a second end region, and a bearing cartridge on at least one of the first end region and the second end region. The bearing cartridge may include a bearing and a bearing ring at least partially surrounding the bearing. The bearing ring may have a geometric symmetry and a cross section that is wider at a first end than at a second end, the first end may oppose the second end.

Tail rotor control system is described for helicopters. A pedal position sensor operable by a pilot yields greater tail rotor RPM relative to the main rotor RPM, giving the pilot increased control over the vehicle. This proves especially useful in certain situations, such as high altitude, where increasing tail rotor speed from main rotor speed can give a pilot increased maneuverability and stability.

An aircraft comprising two half-wings extending to either side of an airframe. The aircraft comprises at least one propeller arranged in the rear part of the airframe. The aircraft comprises a rotary wing provided with two synchronized counter-rotating rotors carried respectively by the half-wings. The aircraft comprises a power plant comprising at least one engine and a mechanical interconnection system connecting the power plant permanently to the rotors except in the event of failure and during training, and to the at least one propeller.

An aircraft comprising two half-wings extending to either side of an airframe. The aircraft comprises at least one propeller arranged in the rear part of the airframe. The aircraft comprises a rotary wing provided with two synchronized counter-rotating rotors carried respectively by the half-wings. The aircraft comprises a power plant comprising at least one engine and a mechanical interconnection system connecting the power plant permanently to the rotors except in the event of failure and during training, and to the at least one propeller.

A rotor assembly for an aircraft operable to generate a variable thrust output at a constant rotational speed. The rotor assembly includes a mast rotatable at the constant speed about a mast axis. A rotor hub is coupled to and rotatable with the mast. The rotor hub includes a plurality of spindle grips extending generally radially outwardly. Each of the spindle grips is coupled to one of a plurality of rotor blades and is operable to rotate therewith about a pitch change axis. A collective pitch control mechanism is coupled to and rotatable with the rotor hub. The collective pitch control mechanism is operably associated with each spindle grip such that actuation of the collective pitch control mechanism rotates each spindle grip about the respective pitch change axis to collectively control the pitch of the rotor blades, thereby generating the variable thrust output.