An example of a hub for a tail rotor includes a body configured to couple to a mast of a rotor system, a trunnion disposed within the body, first and second shafts disposed on opposite sides of the trunnion, first and second end plates secured to the body, and first and second end bearings, the first end bearing disposed between the first shaft and the first end plate and the second end bearing disposed between the second shaft and the second end plate.

An example of a hub for a tail rotor includes a body configured to couple to a mast of a rotor system, a trunnion disposed within the body, first and second shafts disposed on opposite sides of the trunnion, first and second end plates secured to the body, and first and second end bearings, the first end bearing disposed between the first shaft and the first end plate and the second end bearing disposed between the second shaft and the second end plate.

A rotor assembly comprises a rotor hub and rotor-blade assemblies. The rotor hub comprises rotor-blade supports. Each rotor-blade assembly is coupled to a respective one of the rotor-blade supports and comprises a flap axle, a hub connector, a rotor blade, and a torsion strap. The flap axle extends through a respective one of the rotor-blade supports and has a central flap-axle axis. The hub connector is pivotable relative to a rotor-blade support about the central flap-axle axis and defines a central hub-connector axis. The rotor blade is coupled to and is pivotable relative to the hub connector, and, together with the hub connector, is pivotable relative to a respective one of the rotor-blade supports about the central flap-axle axis. The torsion strap has a first end, coupled to the rotor blade, and a second end, through which the flap axle passes.

A rotor assembly comprises a rotor hub and rotor-blade assemblies. The rotor hub comprises rotor-blade supports. Each rotor-blade assembly is coupled to a respective one of the rotor-blade supports and comprises a flap axle, a hub connector, a rotor blade, and a torsion strap. The flap axle extends through a respective one of the rotor-blade supports and has a central flap-axle axis. The hub connector is pivotable relative to a rotor-blade support about the central flap-axle axis and defines a central hub-connector axis. The rotor blade is coupled to and is pivotable relative to the hub connector, and, together with the hub connector, is pivotable relative to a respective one of the rotor-blade supports about the central flap-axle axis. The torsion strap has a first end, coupled to the rotor blade, and a second end, through which the flap axle passes.

Embodiments are directed to a rotor hub assembly comprising a yoke configured to attach rotor blades thereto, a single Hooke's joint configured to attach to, and transmit forces between, a mast and the yoke, and a spherical bearing coupled between the yoke and the mast. Two pillow blocks couple the single Hooke's joint to the yoke. An adapter sleeve is attached to the pillow blocks and is positioned to surround the spherical bearing. The adapter sleeve extends between the single Hooke's joint and the mast. A hub lock extension is attached to the yoke. The hub lock extension is configured to receive a hub lock that prevents gimballing of the yoke when engaged.

Embodiments are directed to a rotor hub assembly comprising a yoke configured to attach rotor blades thereto, a single Hooke's joint configured to attach to, and transmit forces between, a mast and the yoke, and a spherical bearing coupled between the yoke and the mast. Two pillow blocks couple the single Hooke's joint to the yoke. An adapter sleeve is attached to the pillow blocks and is positioned to surround the spherical bearing. The adapter sleeve extends between the single Hooke's joint and the mast. A hub lock extension is attached to the yoke. The hub lock extension is configured to receive a hub lock that prevents gimballing of the yoke when engaged.

An elastomeric bearing assembly has a centrifugal force bearing axially captured relative to a sliding interface. The sliding interface has one or more low friction regions and one or more high friction regions. One or more piezo actuators are configured to force one or more corresponding high friction regions against the centrifugal force bearing when actuated. The sliding interface may have a circular shape, wherein the one or more low friction regions and the one or more high friction regions are alternating concentric segments of the sliding interface. The one or more high friction regions are recessed on the sliding interface relative to the one or more low friction regions.

An elastomeric bearing assembly has a centrifugal force bearing axially captured relative to a sliding interface. The sliding interface has one or more low friction regions and one or more high friction regions. One or more piezo actuators are configured to force one or more corresponding high friction regions against the centrifugal force bearing when actuated. The sliding interface may have a circular shape, wherein the one or more low friction regions and the one or more high friction regions are alternating concentric segments of the sliding interface. The one or more high friction regions are recessed on the sliding interface relative to the one or more low friction regions.

A rotor blade retention assembly includes a central hub, a rotor blade including an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub, a strap member extending along a portion of the rotor blade such that a distal end receiving portion extends into the blade hole, and a retainer assembly disposed within the blade hole and coupled to the strap member. The retainer assembly includes an upper bushing and a lower bushing slidably disposed within the blade hole. The upper bushing includes a counterbored portion. The retainer assembly also includes an outboard blade pin disposed within the distal end receiving portion and includes a blade pin inner cavity.

A rotor blade retention assembly includes a central hub, a rotor blade including an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub, a strap member extending along a portion of the rotor blade such that a distal end receiving portion extends into the blade hole, and a retainer assembly disposed within the blade hole and coupled to the strap member. The retainer assembly includes an upper bushing and a lower bushing slidably disposed within the blade hole. The upper bushing includes a counterbored portion. The retainer assembly also includes an outboard blade pin disposed within the distal end receiving portion and includes a blade pin inner cavity.