Abstract: An apparatus comprising a soft in plane rotor yoke comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material having a plurality of first fibers oriented in a first direction, and a plurality of second layers formed of a second composite fabric material having a plurality of second fibers oriented in a second direction. Included is an apparatus comprising a soft in plane rotor comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material, and a plurality of second layers formed of a second composite fabric material, wherein the soft in plane rotor yoke does not comprise any narrow steered slit tape or filament windings.

Abstract: An apparatus comprising a soft in plane rotor yoke comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material having a plurality of first fibers oriented in a first direction, and a plurality of second layers formed of a second composite fabric material having a plurality of second fibers oriented in a second direction. Included is an apparatus comprising a soft in plane rotor comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material, and a plurality of second layers formed of a second composite fabric material, wherein the soft in plane rotor yoke does not comprise any narrow steered slit tape or filament windings.

Abstract: An apparatus comprising a soft in plane rotor yoke comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material having a plurality of first fibers oriented in a first direction, and a plurality of second layers formed of a second composite fabric material having a plurality of second fibers oriented in a second direction. Included is an apparatus comprising a soft in plane rotor comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material, and a plurality of second layers formed of a second composite fabric material, wherein the soft in plane rotor yoke does not comprise any narrow steered slit tape or filament windings.

Abstract: A helicopter rotor yoke includes a composite laminate having a plurality of plies of fibers disposed in a polymeric matrix. The polymeric matrix includes a toughened polymer at one of a location or zone that experiences high strain levels during use of the rotor yoke.

Abstract: A rotor hub and method to dampen a force exerted on a rotor hub by a rotor blade during flight. The rotor hub including a central member rotatably coupled to a rotor mast, a blade grip rigidly attached to a blade and movably coupled to the central member, and an adjustable damper operably associated with the blade grip. The method includes damping the force exerted on the rotor hub with the adjustable damper and selectively adjusting the adjustable damper between a first spring rate and a second spring rate.

Abstract: An apparatus comprising a soft in plane rotor yoke comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material having a plurality of first fibers oriented in a first direction, and a plurality of second layers formed of a second composite fabric material having a plurality of second fibers oriented in a second direction. Included is an apparatus comprising a soft in plane rotor comprising two longitudinal side portions connected together via two outboard portions, wherein the outboard portions comprise a plurality of first layers formed of a first composite fabric material, and a plurality of second layers formed of a second composite fabric material, wherein the soft in plane rotor yoke does not comprise any narrow steered slit tape or filament windings.

Abstract: A yoke and bearing fitting assembly for a multi-blade aircraft rotor is disclosed. The assembly has a yoke having arms extending generally radially from a central portion of the yoke, the arms each having opposing surfaces. An aperture is formed in each arm and extends between the surfaces. A bearing fitting has a body configured for insertion into the aperture of the yoke and has two rims protruding from a periphery of the body, the body also having a bearing mount adapted for mounting a pitch change bearing assembly to the yoke. Each rim abuts one of the surfaces of the associated yoke arm when the bearing fitting is installed within the aperture, so as to create clamping forces between the rims and the arm and the arm. The bearing fitting transmits forces from the pitch bearing assembly into the yoke.

Abstract: A pitch control system for blades on a rotor of an aircraft has a gimballing rotor hub (31) and a plurality of step-over arms (61) connected to the hub and capable of pivoting relative to the hub about a pivot axis. Each of a plurality of pitch links (55) connects one of the step-over arms (61) to a flight control system for pivoting the connected step-over arm (61) about the pivot axis and relative to the hub in response to inputs from the control system. Each of a plurality of step-over links (69) connects one of the step-over arms (61) to one of the blades for rotating the associated blade about the pitch axis in response to pivoting of the associated step-over arm.

Abstract: A rotor hub and method to dampen a force exerted on a rotor hub by a rotor blade during flight. The rotor hub including a central member rotatably coupled to a rotor mast, a blade grip rigidly attached to a blade and movably coupled to the central member, and an adjustable damper operably associated with the blade grip. The method includes damping the force exerted on the rotor hub with the adjustable damper and selectively adjusting the adjustable damper between a first spring rate and a second spring rate.

Abstract: A damper has a piston having an axis, an outer surface, and opposing ends. Elastomeric seals are in sealing contact with the outer surface of the piston, the seals being coaxial with the piston and limiting movement of the piston to a path along the axis of the piston. The seals also define fluid chambers adjacent the ends of the piston. A primary passage communicates the fluid chambers, and a selectively switchable valve for controls a flow of fluid from one of the chambers to another of the chambers through the primary passage. When the flow of fluid through the primary passage is permitted, movement of the piston is resisted by a first spring rate due to a shear force required to cause shear deflection of the seals. When the flow of fluid through the primary passage is restricted, movement of the piston is resisted by a second spring rate due to a fluid force required to cause bulging deflection of the seals.

Abstract: A joint is configured for use with a rotary-wing aircraft having at least one engine. A driver is coupled to an output shaft of the engine, the driver being rotatable about an axis. A yoke is at least partially rotatable relative to the driver about a first center of rotation, the center of rotation being located on the axis. A plurality of upright links couple the yoke to the driver, each link being translatable relative to the yoke, the driver, or both. Each link is also rotatable relative to the yoke, the driver, or both, about a second center of rotation.

Abstract: A rotor hub assembly for a rotary-wing aircraft has a central member and a plurality of blade grips adapted for attaching rotor blades to the central member. The blade grips are pivotally attached to the central member and are capable of pivoting about a pivot axis generally normal to a plane of rotation of the blades. The pivoting allows for in-plane motion of the blades relative to the central member. A damper is operably connected to each blade grip for damping the in-plane motion of the associated blade, each damper being selectively switchable between at least two spring rates.

Abstract: A pitch control system for blades on a rotor of an aircraft has a gimballing rotor hub (31) and a plurality of step-over arms (61) connected to the hub and capable of pivoting relative to the hub about a pivot axis. Each of a plurality of pitch links (55) connects one of the step-over arms (61) to a flight control system for pivoting the connected step-over arm (61) about the pivot axis and relative to the hub in response to inputs from the control system. Each of a plurality of step-over links (69) connects one of the step-over arms (61) to one of the blades for rotating the associated blade about the pitch axis in response to pivoting of the associated step-over arm.

Abstract: A constant-velocity joint is configured for use with a rotary-wing aircraft having at least one engine. A driver is coupled to an output shaft of the engine, the driver being rotatable about an axis. A yoke is at least partially rotatable relative to the driver about a first center of rotation, the center of rotation being located on the axis. A plurality of upright links couple the yoke to the driver, each link being translatable relative to the yoke, the driver, or both. Each link is also rotatable relative to the yoke, the driver, or both, about a second center of rotation.

Abstract: The subject tiltrotor aircraft has three modes of operation: airplane mode, helicopter mode, and transition mode. A tilting mast, which transitions the aircraft between airplane mode and helicopter mode, is controlled by systems that allow selective movement of the rotor blades between the flight modes. A hub couples the rotor blades to the tilting mast such that torque and thrust are transferred, while allowing rotor thrust vector tilting. A main swash plate controls rotor thrust vector direction. Pitch horns are coupled to the rotor blades and the main swash plate via pitch links such that swash plate inputs are communicated to the rotor blades. The pitch links are coupled at “delta-3” values that are not optimum. A feedback swash plate and feedback links receive disk tilting inputs from the rotor blades, and supply inputs to the main swash plate, which compensates for the less than optimum delta-3 coupling.