The present invention includes a rotor hub system, comprising: a teetering rotor hub disposed about a mast, the teetering rotor hub comprising: a first and a second yoke; each connected to a set of rotor blades, wherein the second set of rotor blades and the first set of rotor blades are disposed in a common plane, but the first and the second yoke do not come in contact.

The present invention includes a rotor hub system, comprising: a teetering rotor hub disposed about a mast, the teetering rotor hub comprising: a first and a second yoke; each connected to a set of rotor blades, wherein the second set of rotor blades and the first set of rotor blades are disposed in a common plane, but the first and the second yoke do not come in contact.

A magnetorheological fluid clutch apparatus comprises an input rotor adapted to be coupled to a power input, the input rotor having a first set of at least one input shear surface, and a second set of at least one output shear surface. An output rotor is rotatably mounted about the input rotor for rotating about a common axis with the input rotor, the output rotor having a first set of at least one output shear surface, and a second set of at least one output shear surface, the first sets of the input rotor and the output rotor separated by at least a first annular space and forming a first transmission set, the second sets of the input rotor and the output rotor separated by at least a second annular space and forming a second transmission set. Magnetorheological fluid is in each of the annular spaces, the MR fluid configured to generate a variable amount of torque transmission between the sets of input rotor and output rotor when subjected to a magnetic field. A pair of electromagnets are configured to deliver a magnetic field through the MR fluid, the electromagnets configured to vary the strength of the magnetic field, whereby actuation of at least one of the pair of electromagnets results in torque transmission from the at least one input rotor to the output rotor.

A rotor hub assembly for a rotorcraft includes a yoke forming a bearing bore. The yoke has a teetering axis extending through the bearing bore. The rotor hub assembly includes a flapping bearing disposed in the bearing bore. The flapping bearing is operable to regulate teetering of the yoke about the teetering axis. The rotor hub assembly includes an axial spring abutting the flapping, thereby reducing movement of the flapping bearing along the teetering axis.

A rotor hub assembly for a rotorcraft includes a yoke forming a bearing bore. The yoke has a teetering axis extending through the bearing bore. The rotor hub assembly includes a flapping bearing disposed in the bearing bore. The flapping bearing is operable to regulate teetering of the yoke about the teetering axis. The rotor hub assembly includes an axial spring abutting the flapping, thereby reducing movement of the flapping bearing along the teetering axis.

A control system for controlling a rotorcraft rotor, to a rotorcraft fitted therewith, and to a corresponding control method. The system comprises selector means for defining at least two disjoint position ranges for the control member between two physical abutments corresponding to the movement limits of the control member, a first position range being defined between at least two first limit values about a zero force position of the control member, and at least one second position range being defined between at least one of the at least two first limit values and at least one second limit value; and control means for allocating a first control law to the first position range of the control member and a second control law to the second position range of the control member, the first and second control laws being selected to be mutually distinct.

A control system for controlling a rotorcraft rotor, to a rotorcraft fitted therewith, and to a corresponding control method. The system comprises selector means for defining at least two disjoint position ranges for the control member between two physical abutments corresponding to the movement limits of the control member, a first position range being defined between at least two first limit values about a zero force position of the control member, and at least one second position range being defined between at least one of the at least two first limit values and at least one second limit value; and control means for allocating a first control law to the first position range of the control member and a second control law to the second position range of the control member, the first and second control laws being selected to be mutually distinct.

A control horn arrangement includes a control horn body with an inboard end and an opposed outboard end. The control horn body defines a torque tube axis which extends between the inboard and outboard end of the control horn body. An inner flange and an outer flange are disposed on the outboard end of the control horn body. The inner flange and the outer flange extend about the torque tube axis and define between one another a receptacle to fix a torque tube to the outboard end of the control horn body.

Systems and methods are provided to control a rotor blade pitch. In one example, a system comprises a ratchet mechanism comprising a ratchet wheel configured to be rotated by a motor about a first axis. The ratchet mechanism comprises one or more followers each of which is coupled to the ratchet wheel. The ratchet wheel rotates the one or more followers in a first direction about the first axis when the ratchet wheel is rotated by the motor in the first direction about the first axis. One or more rotor blades rotate about the first axis. Each rotor blade is affixed to a respective follower. Each follower controls a pitch of the respective rotor blade based on a position of the follower relative to the ratchet wheel.

Systems and methods are provided to control a rotor blade pitch. In one example, a system comprises a ratchet mechanism comprising a ratchet wheel configured to be rotated by a motor about a first axis. The ratchet mechanism comprises one or more followers each of which is coupled to the ratchet wheel. The ratchet wheel rotates the one or more followers in a first direction about the first axis when the ratchet wheel is rotated by the motor in the first direction about the first axis. One or more rotor blades rotate about the first axis. Each rotor blade is affixed to a respective follower. Each follower controls a pitch of the respective rotor blade based on a position of the follower relative to the ratchet wheel.