Abstract: A high stiffness hub assembly for a proprotor system operable to rotate with a mast of a tiltrotor aircraft having helicopter and airplane flight modes. The hub assembly includes a yoke and a constant velocity joint assembly. The yoke has four blade arms each adapted to hold a proprotor blade. The constant velocity joint assembly provides a torque path from the mast to the yoke that includes a trunnion assembly, four drive links and four pillow blocks. The trunnion assembly is coupled to the mast and has four outwardly extending trunnions. Each drive link has a leading bearing coupled to one of the trunnions and a trailing bearing coupled to one of the pillow blocks. Each pillow block is independently mounted between an upper surface of the yoke and a hub plate with two connection members that extend through the yoke and the pillow block.

Abstract: An apparatus comprising a drivelink comprising a housing including a socket, wherein the socket comprises a cross-sectional area, and a bearing cartridge disposed within the socket, wherein a cross-sectional area of the cartridge is less than the cross-sectional area of the socket. An apparatus comprising a drivelink comprising a housing having a socket, and a bearing cartridge positioned within the socket and comprising a first portion and a second portion, wherein the first portion is configured to undergo compression when a load is applied to the drivelink, and wherein the second portion is configured to not be in tension when the load is applied to the drivelink.

Abstract: A rotor hub assembly that includes a yoke configured to attach blades thereto, a universal joint configured to attach to, and transmit forces between, a mast and the yoke, and an elastomeric member configured to attenuate vibrations transmitted from the universal joint to the mast.

Abstract: A proprotor system for a tiltrotor aircraft having helicopter and airplane flight modes 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 with each bearing assembly including a bearing cage, a shear bearing and a centrifugal force bearing. Each of a plurality of inboard beams is disposed at least partially between one of the centrifugal force bearings and one of the shear bearings. Each of a plurality of proprotor blades is coupled to one of the inboard beams. Hub bolts couple each of the bearing cages to the yoke such that the hub bolts provide centrifugal force load paths between the bearing assemblies and the yoke inboard of the inboard pockets.

Abstract: A wing airframe for a wing of a tiltrotor aircraft includes a wing airframe core assembly and a wing skin assembly disposed on the wing airframe core assembly. The wing skin assembly includes an outer skin and a damping sublayer, the damping sublayer interposed between the outer skin and the wing airframe core assembly. The tiltrotor aircraft includes a pylon assembly subject to aeroelastic movement during forward flight. The wing is subject to deflection in response to the aeroelastic movement of the pylon assembly.

Abstract: A proprotor system operable for use on a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode. The proprotor system includes a rotor hub and a plurality of proprotor blades coupled to the rotor hub such that each proprotor blade has three independent degrees of freedom relative to the rotor hub including blade pitch about a pitch change axis, blade flap about a flapping axis and lead-lag about a lead-lag axis. Each of a plurality of spherical bearings couples one of the proprotor blades with the rotor hub. In addition, each of a plurality of lead-lag dampers couples one of the proprotor blades with the rotor hub, wherein each lead-lag damper is aligned with the pitch change axis of the respective proprotor blade, thereby providing pitch independent lead-lag damping.

Abstract: The present invention includes a system and method for slowing the rotation of a rotor using, for example, rotor brake system for a rotorcraft comprising: one or more generators connected to a main rotor gearbox; an electric distributed anti-torque system mounted on a tail boom of the rotorcraft comprising two or more electric motors connected to the one or more generators, wherein the two or more electric motors are connected to one or more blades; and wherein a rotation of the rotor is slowed by placing a drive load on the main rotor gearbox with the one or more generators to bleed the mechanical power from rotor into electrical power via the two or more electric motors, wherein the electric distributed anti-torque system generates thrust in opposing directions.

Abstract: A hub system comprises at least one yoke, at least one shear bearing, and at least one mast adapter. The at least one mast adapter is configured to support the at least one yoke and the at least one shear bearing, and the at least one yoke has a flapping hinge that is non-coincident with a flapping hinge of the at least one shear bearing. Another hub system comprises a stacked yoke and a mast adapter. The mast adapter is configured to transfer rotation from a rotor mast to the hub system to rotate the hub system about a central axis of rotation. The mast adapter is further configured to support the stacked yoke such that each yoke in the stacked yoke is configured to accommodate at least some amount of rotation about an axis that is perpendicular to or about perpendicular to the central axis of rotation.

Abstract: An aircraft rotor assembly has a yoke with at least two arms extending therefrom. The yoke is attached to a mast through a constant-velocity joint, thereby permitting axial tilt of the yoke relative to the mast. Each arm of the yoke includes an axisymmetric elastomeric bearing with a spherical central member and two opposite partially-spherical members attached to the central member. Each axisymmetric bearing cooperates with a cup and a bracket. Each cup is attached to one of the yoke arms and each bracket is attached to a blade cuff.

Abstract: An inflight connection system for aircraft having at least one wing with a wingtip includes, for each aircraft, a primary connector selectively extendable from the wingtip, an alignment connector selectively extendable from the wingtip and a male and female connector assembly disposed proximate the wingtip. The primary connectors extend a greater distance from the wingtips than the alignment connectors such that the primary connectors form a first connection between the aircraft when the aircraft are flying in a connection pattern. Thereafter, retraction of the primary connectors reduces wingtip separation of the aircraft such that the alignment connectors form a second connection between the aircraft establishing coarse alignment therebetween. Thereafter, retraction of the primary and alignment connectors further reduces wingtip separation of the aircraft such that the male and female connector assemblies form a third connection between the aircraft establishing fine alignment therebetween.

Abstract: An apparatus comprising a drivelink comprising a housing including a socket, wherein the socket comprises a cross-sectional area, and a bearing cartridge disposed within the socket, wherein a cross-sectional area of the cartridge is less than the cross-sectional area of the socket. An apparatus comprising a drivelink comprising a housing having a socket, and a bearing cartridge positioned within the socket and comprising a first portion and a second portion, wherein the first portion is configured to undergo compression when a load is applied to the drivelink, and wherein the second portion is configured to not be in tension when the load is applied to the drivelink.

Abstract: A hub system comprises at least one yoke, at least one shear bearing, and at least one mast adapter. The at least one mast adapter is configured to support the at least one yoke and the at least one shear bearing, and the at least one yoke has a flapping hinge that is non-coincident with a flapping hinge of the at least one shear bearing. Another hub system comprises a stacked yoke and a mast adapter. The mast adapter is configured to transfer rotation from a rotor mast to the hub system to rotate the hub system about a central axis of rotation. The mast adapter is further configured to support the stacked yoke such that each yoke in the stacked yoke is configured to accommodate at least some amount of rotation about an axis that is perpendicular to or about perpendicular to the central axis of rotation.

Abstract: A high stiffness hub assembly for a proprotor system operable to rotate with a mast of a tiltrotor aircraft having helicopter and airplane flight modes. The hub assembly includes a yoke and a constant velocity joint assembly. The yoke has four blade arms each adapted to hold a proprotor blade. The constant velocity joint assembly provides a torque path from the mast to the yoke that includes a trunnion assembly, four drive links and four pillow blocks. The trunnion assembly is coupled to the mast and has four outwardly extending trunnions. Each drive link has a leading bearing coupled to one of the trunnions and a trailing bearing coupled to one of the pillow blocks. Each pillow block is independently mounted between an upper surface of the yoke and a hub plate with two connection members that extend through the yoke and the pillow block.

Abstract: A vibration isolation system for an advancing blade concept rotorcraft having a pylon assembly and an airframe. The vibration isolation system includes one or more pylon links each having first and second ends with the first end coupled to the pylon assembly and the second end coupled to the airframe. Each pylon link includes a vibration isolator, such as a Liquid Inertia Vibration Eliminator unit, that is interposed between the pylon assembly and the airframe. The vibration isolator system is operable to reduce or eliminate transmission of the pylon assembly vibration to the airframe.

Abstract: An inflight connection system for aircraft having at least one wing with a wingtip includes, for each aircraft, a primary connector selectively extendable from the wingtip, an alignment connector selectively extendable from the wingtip and a male and female connector assembly disposed proximate the wingtip. The primary connectors extend a greater distance from the wingtips than the alignment connectors such that the primary connectors form a first connection between the aircraft when the aircraft are flying in a connection pattern. Thereafter, retraction of the primary connectors reduces wingtip separation of the aircraft such that the alignment connectors form a second connection between the aircraft establishing coarse alignment therebetween. Thereafter, retraction of the primary and alignment connectors further reduces wingtip separation of the aircraft such that the male and female connector assemblies form a third connection between the aircraft establishing fine alignment therebetween.

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 rotorcraft has a low density altitude flight mode and a high density altitude flight mode. The rotorcraft includes a turboshaft engine forming a gas path in sequence through an air inlet section, a compressor section, a combustor section, a turbine section and an exhaust section. A drive system is coupled to the engine and is operable responsive to rotation of at least a portion of the turbine section. A rotor is coupled to the drive system and is operable to receive torque and rotational energy therefrom. A fuel injection system supplies fuel to the combustor section. An oxidizer injection system and a coolant injection system are used to selectively inject an oxidizer and a coolant into the gas path when it is desired to operate the rotorcraft in the high density altitude flight mode, thereby increasing the altitude density ceiling of the rotorcraft for maneuvers including takeoffs and landings.

Abstract: A tiltrotor aircraft has a fuselage and a wing having upper and lower surfaces with a plurality of channels extending therebetween, each with a cycloidal rotor mounted therein. At least two pylon assemblies are rotatably coupled to the wing to selectively operate the tiltrotor aircraft between helicopter and airplane flight modes. Each pylon assembly includes a mast and a proprotor assembly operable to rotate with the mast to generate thrust. At least one engine provides torque and rotational energy to the proprotor assemblies and the propulsion assemblies. Each of the cycloidal rotors has a plurality of blades that travels in a generally circular path and has a plurality of pitch angle configurations such that each cycloidal rotor is operable to generate a variable thrust and a variable thrust vector, thereby providing vertical lift augmentation, roll control, yaw control and/or pitch control in the helicopter flight mode.

Abstract: An aircraft rotor mast assembly that includes a composite rotor mast and a rotor housing surrounding the rotor mast. The rotor mast includes a first end, a second end, and a length therebetween. The rotor mast includes a plurality of circular openings proximate the first end to accommodate bolts for the fixation of a rotor hub to the rotor mast. The second end of the rotor mast includes a flange, wherein the flange defines a plurality of openings therethrough to accommodate the attachment of the rotor mast to a transmission.

Abstract: 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 blade support assemblies coupling the proprotor blades with the hub. Each blade support assembly includes a flapping bearing coupled to the hub and a yoke having first and second longitudinal sections with outboard grip members and an inboard arcuate section connecting the first and second longitudinal sections and coupled to the flapping bearing. A lead-lag damper is coupled between the hub and an inboard station of the respective proprotor blade. A twist shank is coupled between the outboard grip members of the yoke and an outboard station of the respective the proprotor blade. The twist shank defines a virtual lead-lag hinge outboard of the yoke and coincident with the respective pitch change axis.