Embodiments are directed to a double Hooke's joint gimbal in a rotor system. An upper Hooke's joint has four arms extending radially outward to define first and second axes, and a lower Hooke's joint has four arms extending radially outward to define third and fourth axes. A pair of connectors couple the upper Hooke's joint and the lower Hooke's joint. A first set of bearings are positioned between arms on the upper and lower Hooke's joints and the connectors. The first set of bearings comprise an elastomer, such as elastomeric journal bearings. The upper Hooke's joint is coupled to a yoke and rotor blades by a driver assembly that allows rotor blade flapping. The lower Hooke's joint is coupled to and driven by a mast. A spherical bearing allows the upper Hooke's joint to move laterally along the mast.

The present application provides a drive link for a constant-velocity joint of an aircraft rotor, the link connecting a drive hub attached to a driveshaft to a rotor yoke. The link comprises a leading bearing connected to the drive hub, a trailing bearing connected to the yoke, a central portion between the bearings, and a tension loop connecting the bearings. The tension loop is formed from a composite material and is formed as a continuous band. The tension loop transfers drive forces from the leading bearing to the trailing bearing for driving the yoke in rotation with the driveshaft.

The present application provides a drive link for a constant-velocity joint of an aircraft rotor, the link connecting a drive hub attached to a driveshaft to a rotor yoke. The link comprises a leading bearing connected to the drive hub, a trailing bearing connected to the yoke, a central portion between the bearings, and a tension loop connecting the bearings. The tension loop is formed from a composite material and is formed as a continuous band. The tension loop transfers drive forces from the leading bearing to the trailing bearing for driving the yoke in rotation with the driveshaft.

A gimbal joint may employ a plurality of wear sleeves, each disposed between a pin or pin receptive bore of a first structure and a corresponding bore or pin of a second structure and between another pin or bore of the second structure and a corresponding bore or pin of a third structure. Each of these structures may be adapted to rotate in a single plane, with one structure adapted to also tilt about a first axis, and one other structure adapted to tilt about a second axis. Each integral flanged wear sleeve may comprise a right circular hollow cylindrical body portion, which may be interiorly sized to be retained on one of the pins and externally sized to be retained in one of the pin receptive bores, and a flange portion may radiate from one end of the cylindrical body portion.

A gimbal joint may employ a plurality of wear sleeves, each disposed between a pin or pin receptive bore of a first structure and a corresponding bore or pin of a second structure and between another pin or bore of the second structure and a corresponding bore or pin of a third structure. Each of these structures may be adapted to rotate in a single plane, with one structure adapted to also tilt about a first axis, and one other structure adapted to tilt about a second axis. Each integral flanged wear sleeve may comprise a right circular hollow cylindrical body portion, which may be interiorly sized to be retained on one of the pins and externally sized to be retained in one of the pin receptive bores, and a flange portion may radiate from one end of the cylindrical body portion.

A coaxial rotor system for a rotorcraft includes a mast, a top rotor assembly and a bottom rotor assembly. The top rotor assembly is coupled to the distal end of the mast. The bottom rotor assembly includes a motor configured to provide rotational energy to the mast, thereby rotating the top rotor assembly. The bottom rotor assembly experiences a torque reaction force responsive to the motor rotating the mast such that the top and bottom rotor assemblies counter rotate.

In response to a change in a state of at least some part of a vehicle, a control signal associated with countering the change in the state while the vehicle is in an occupant change state is generated. The control signal is sent to a rotor in the vehicle while the vehicle is in the occupant change state, wherein the control signal causes the rotor to move in a manner that is counter to the change in the state and the rotor rotates about a substantially vertical axis of rotation and enables the vehicle to perform vertical takeoffs and landings.

A method of selectively preventing flapping of a rotor hub includes providing a flapping lock proximate to a rotor hub and shaft assembly and moving the flapping lock from an unlocked position to a locked position, the flapping lock operable in the locked position to prevent at least some flapping movement of the rotor hub relative to the shaft, the flapping lock operable in the unlocked position to allow the at least some flapping movement of the rotor hub relative to the shaft.

A method of selectively preventing flapping of a rotor hub includes providing a flapping lock proximate to a rotor hub and shaft assembly and moving the flapping lock from an unlocked position to a locked position, the flapping lock operable in the locked position to prevent at least some flapping movement of the rotor hub relative to the shaft, the flapping lock operable in the unlocked position to allow the at least some flapping movement of the rotor hub relative to the shaft.

A passive hub flapping lock including: one or more lever arms, each lever arm rotatably coupled to a pivot and comprising a first lever arm end and a second lever arm end; one or more stop wedges; one or more frames coupled to the one or more stop wedges, each frame coupled to the first lever arm end of one of the one or more lever arms; one or more weight sets, each weight set comprising one or more weights coupled to the second lever arm end of one of the one or more lever arms; and one or more pivot torsion springs, each pivot torsion spring positioned at the pivot.