The bearing system is configured for treating and reacting dynamic loading within a rotor hub of rotorcraft. The bearing system includes an outer member having a plurality of alternating outer elastomeric layers and shim layers. The outer member has an inboard surface configured for bonding to an inboard bearing support, and the outer member has an outboard surface configured for bonding to an outboard bearing support. The bearing system has an inner member bonded to an interior surface of the outer member. The inner member can include a rigid inner core, as well as a plurality of elastomeric layers and shim layers configured to react torsional movements of the rotor blade.

The bearing system is configured for treating and reacting dynamic loading within a rotor hub of rotorcraft. The bearing system includes an outer member having a plurality of alternating outer elastomeric layers and shim layers. The outer member has an inboard surface configured for bonding to an inboard bearing support, and the outer member has an outboard surface configured for bonding to an outboard bearing support. The bearing system has an inner member bonded to an interior surface of the outer member. The inner member can include a rigid inner core, as well as a plurality of elastomeric layers and shim layers configured to react torsional movements of the rotor blade.

A rotorcraft having a rotor system including a yoke, a plurality of grip assemblies, each of which is hingedly attach a rotor blade to the yoke, a plurality of flap stops, each flap stop attached to a respective grip assembly, a channel bounded by an upper and lower retaining surfaces, and a droop ring slideably disposed in the channel of the droop limiting system. The droop ring has a body with an inner surface, an outer surface, and a first end surface between the inner surface and the outer surface. The droop ring further has a first wear element removably disposed at the first end surface and extending above the first end surface and spaces the first end surface apart from the channel. Each flap stop is arranged to contact the outer surface of the droop ring and limit a downward droop of the respective rotor blade.

A soft-in-plane proprotor system for a tiltrotor aircraft having a helicopter mode and an airplane mode. The proprotor system includes a hub, a plurality of proprotor blades and a plurality of loop yokes, each coupling one of the proprotor blades with the hub and each including first and second longitudinal sections extending between inboard and outboard arcuate sections and a bearing assembly disposed between the inboard and outboard arcuate sections of each loop yoke. Each bearing assembly includes a flapping bearing disposed generally within the inboard arcuate section of the respective loop yoke and coupled to the hub, a lead-lag damper coupled to the hub, a centrifugal force bearing disposed generally within the outboard arcuate section of the respective loop yoke and a blade anchor coupled between the lead-lag damper and the centrifugal force bearing. The blade anchor is also coupled to the respective proprotor blade.

A soft-in-plane proprotor system for a tiltrotor aircraft having a helicopter mode and an airplane mode. The proprotor system includes a hub, a plurality of proprotor blades and a plurality of loop yokes, each coupling one of the proprotor blades with the hub and each including first and second longitudinal sections extending between inboard and outboard arcuate sections and a bearing assembly disposed between the inboard and outboard arcuate sections of each loop yoke. Each bearing assembly includes a flapping bearing disposed generally within the inboard arcuate section of the respective loop yoke and coupled to the hub, a lead-lag damper coupled to the hub, a centrifugal force bearing disposed generally within the outboard arcuate section of the respective loop yoke and a blade anchor coupled between the lead-lag damper and the centrifugal force bearing. The blade anchor is also coupled to the respective proprotor blade.

A yoke for providing a centrifugal force retention load path between a proprotor blade and a hub of a soft-in-plane proprotor system operable for use on a tiltrotor aircraft. The yoke includes a continuous loop having a longitudinal axis and first and second longitudinal sections extending between inboard and outboard arcuate sections. A flapping bearing receiving region is disposed at least partially within the inboard arcuate section to an interior of the continuous loop. A centrifugal force bearing receiving region is disposed at least partially within the outboard arcuate section to the interior of the continuous loop. The continuous loop is formed from a composite material having a plurality of double bias material plies and a plurality of unidirectional material plies such that the number of unidirectional material plies is greater than the number of double bias material plies.

A yoke for providing a centrifugal force retention load path between a proprotor blade and a hub of a soft-in-plane proprotor system operable for use on a tiltrotor aircraft. The yoke includes a continuous loop having a longitudinal axis and first and second longitudinal sections extending between inboard and outboard arcuate sections. A flapping bearing receiving region is disposed at least partially within the inboard arcuate section to an interior of the continuous loop. A centrifugal force bearing receiving region is disposed at least partially within the outboard arcuate section to the interior of the continuous loop. The continuous loop is formed from a composite material having a plurality of double bias material plies and a plurality of unidirectional material plies such that the number of unidirectional material plies is greater than the number of double bias material plies.

A bearing assembly for coupling a proprotor blade to a yoke in a proprotor system. The bearing assembly is positionable within an inboard pocket of a blade arm of the yoke. The proprotor system is operable for use on a tiltrotor aircraft having helicopter and airplane flight modes. The bearing assembly includes a centrifugal force bearing and a shear bearing having an inboard beam coupled therebetween. The centrifugal force bearing has a mating surface, a lateral movement constraint feature and at least one radially extending anti-rotation feature. The inboard beam has a mating surface in a contact relationship with the mating surface of the centrifugal force bearing, a lateral movement constraint feature operably associated with the lateral movement constraint feature of the centrifugal force bearing and at least one radially extending anti-rotation feature that corresponds with the at least one radially extending anti-rotation feature of the centrifugal force bearing.

An elastomeric bearing includes a first race having an axis of rotation, a second race coaxially arranged relative to the first race and spaced from the first race by a gap and a bearing body in the gap connecting the first race to the second race. The bearing body is formed from a first plurality of elastomeric laminae coaxial with the first race and a second plurality of carbon fiber laminae coaxial with the first race, and the elastomeric laminae and the carbon fiber laminae alternate in a direction from the first race to the second race. The carbon fiber laminae may each include multiple sheets of carbon fibers embedded in a thermoplastic such as polyether ether ketone (PEEK).

A proprotor system for a tiltrotor aircraft includes a yoke having a plurality of blade arms each having an inboard pocket. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets. Each of a plurality of inboard beams is disposed at least partially between a centrifugal force bearing and a shear bearing of each bearing assembly and has a proprotor blade coupled thereto. Each of a plurality of latch assemblies selectively couples one of the bearing assemblies to the yoke. Each latch assembly is rotatable relative to the yoke between an engaged position wherein the latch assembly is engagable with one of the bearing assemblies to couple the bearing assembly to the yoke and a disengaged position wherein the latch assembly is disengaged from the respective bearing assembly enabling installation and removal of the respective bearing assembly relative to the respective pocket.