Abstract: A rotor assembly for a rotary wing aircraft includes a rotor hub having a central axis. The rotor hub is rotatable about the central axis. A plurality of flexible structural members extend radially outwardly from the rotor hub. Each flexible structural member is substantially U-shaped having a first arm extending from the hub, a second arm extending from the hub, and an end portion connecting the first arm to the second arm at a radially outboard end of the flexible structural member. The first arm, the second arm and/or the end portion have a cross section with a height along the central axis greater than a thickness of the cross section to increase stiffness of the rotor assembly along the central axis. The rotor assembly further includes a plurality of rotor blades, each rotor blade being secured to each flexible structural member of the plurality of flexible structural members.

Abstract: A rotor blade rotated about a rotor hub is provided including a first section configured to mount to the rotor hub. The first section includes a spindle and an inboard torque tube surrounding a portion of the spindle. A second section of the rotor blade includes a flexbeam and an outboard torque tube attached to and surrounding the flexbeam. An inboard end of the flexbeam is rotatable coupled to a first end of the spindle. The second section is configured to rotate about a blade axis between an aligned position and a rotated position. A transitional brace configured to surround a portion of the rotor blade adjacent the coupled flexbeam and spindle is movable between a first position and a second position. When in the first position, the transitional brace limits movement of the second section about the blade axis.

Abstract: A pin wrap having a unitary construction that includes a first elongated arm extending from an inboard end to an outboard end; a second elongated arm extending from the inboard end to the outboard end; and a curved end having an internal surface and a directly opposing external surface. The curved end integrally connects the first elongated arm to the second elongated arm at the outboard end. Also, the curved end is arcuate having a plurality of radii of curvatures. A blade and a helicopter with a blade can include the pin wrap.

Abstract: An aircraft is provided and includes an airframe, an engine, a drive portion driven by the engine, a rotor apparatus, which includes a rotor rotatable relative to the airframe and a fairing, a gearbox disposed to transmit rotational energy from the drive portion to the rotor to drive the rotor to rotate relative to the airframe and which generates a rotor rotation vibration, support members by which the gearbox is disposed on the airframe and an actuation system including actuation elements disposed at the fairing, the actuation system being configured to generate an anti-vibration moment using the actuation elements disposed at the fairing to counter the rotor rotation vibration.

Abstract: A pitch bearing for connecting first and second articles is provided. The first article includes a first curved outer surface and the second article includes a second curved outer surface opposite the first curved outer surface. The pitch bearing includes an axisymmetric structure interposed between the first and second curved outer surfaces. The axisymmetric structure includes compliant layers and stabilizing layers interleaved between the compliant layers. The compliant layers and the stabilizing layers proximate to the first article haves a curvature matching that of the first curved outer surface. The compliant layers and the stabilizing layers proximate to the second article have a curvature matching that of the second curved outer surface. A shear stiffness of each of the stabilizing layers is greater than a shear stiffness of each of the compliant layers.

Abstract: A cylindrical elastomeric bearing including a plurality of elastomeric layers arranged about a central bore. The elastomeric layers are characterized by a middle portion having a first thickness and two outer portions having a second thickness, the second thickness being greater than the first thickness, the one or more elastomeric layers being tapered between the middle portion and the outer portions. One or more shim layers, each of the plurality of shim layers being arranged between two of the plurality of elastomeric layers. The shim layers are shaped to fit with the elastomer layers.

Abstract: A fairing system, includes a hub fairing and a fixed fairing, such as a shaft fairing or a pylon fairing, both arranged about a rotation axis. A gap is defined between the hub fairing and the fixed fairing, and a seal assembly is axially interposed between the hub fairing and the fixed fairing. The fixed fairing and the hub fairing are both removably mounted to the seal assembly such that either or both of the fairings can be dismounted from the seal assembly without disturbing the seal assembly to provide access to components disposed within the fairing.

Abstract: A bearing arrangement for use with a structure defining an outer surface which expands and contracts inward and outward relative to the structure includes, a member having at least one inner surface to face the outer surface, and at least one protrusion extending from the inner surface, the at least one protrusion being biased toward and in contact with the outer surface and maintains contact as the structure expands and contracts.

Abstract: A method of forming an in-wing device-retention assembly includes inserting a first plate into a wing, the wing having a wide end and a narrow end. The method includes inserting a second plate into the wing, inserting a wedge plate into the wing and positioning the wedge plate between the first plate and the second plate, and applying a force to the wedge plate in a direction toward the narrow end to fix the first plate, the second plate and the wedge plate within the wing.

Abstract: An aircraft includes an airframe; an extending tail; a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly; a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe; an upper hub fairing positioned at the upper rotor assembly; a lower hub fairing positioned at the lower rotor assembly; and a shaft fairing disposed between the upper hub fairing and the lower hub fairing; wherein the upper hub fairing is substantially sealed to the shaft fairing and the lower hub fairing is substantially sealed to the shaft fairing.

Abstract: An aircraft includes an airframe; an extending tail; a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly; and a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe; wherein a ratio of (i) the hub separation between the hub of the upper rotor assembly and the hub of the lower rotor assembly to (ii) a radius of the upper rotor assembly is between about 0.1 and about 0.135.

Abstract: A main rotor system for a rotary wing aircraft is provided including a lower rotor hub to which lower rotor blades are attachable. The lower rotor hub rotates about an axis in a first direction. A hollow rotor shaft extends through the lower rotor hub. The first end of the rotor shaft couples to a component of the rotary wing aircraft for rotation about an axis. An upper rotor hub arranged at the second end of the rotor shaft includes a plurality of similar upper rotor members equidistantly spaced about a circumference of the rotor shaft to form an open center aligned with a hollow interior of the rotor shaft. An opening configured to receive an upper rotor blade is formed between adjacent upper rotor members and the upper rotor hub is configured to rotate in a second direction, opposite the first direction.

Abstract: A cylindrical elastomeric bearing including a plurality of elastomeric layers arranged about a central bore. The elastomeric layers are characterized by a middle portion having a first thickness and two outer portions having a second thickness, the second thickness being greater than the first thickness, the one or more elastomeric layers being tapered between the middle portion and the outer portions. One or more shim layers, each of the plurality of shim layers being arranged between two of the plurality of elastomeric layers. The shim layers are shaped to fit with the elastomer layers.

Abstract: An aircraft is provided and includes an airframe, an engine, a drive portion driven by the engine, a rotor apparatus, which includes a rotor rotatable relative to the airframe and a fairing, a gearbox disposed to transmit rotational energy from the drive portion to the rotor to drive the rotor to rotate relative to the airframe and which generates a rotor rotation vibration, support members by which the gearbox is disposed on the airframe and an actuation system including actuation elements disposed at the fairing, the actuation system being configured to generate an anti-vibration moment using the actuation elements disposed at the fairing to counter the rotor rotation vibration.

Abstract: A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

Abstract: An aircraft is provided including an airframe, an extending tail, one or more engines supported by the airframe, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail. The translational thrust system providing translational thrust to the airframe. A gearbox configured to transfer power from the engine to the main rotor assembly. A flight control computer to independently control one or more of the engine, the upper rotor assembly, the lower rotor assembly, and the translational thrust system. The flight control computer, in response to at least one control command, engages or disengages the translational thrust system, while maintaining controlled powered flight.

Abstract: A spar for a rotor blade assembly is provided including a generally hollow tubular body. A spacer protrudes from at least one surface of the body along a length of the body. A hole extends through the body and the spacer. The hole is configured to align with a through hole in an adjacent flexbeam assembly. The spacer is configured to contact a surface of the adjacent flexbeam assembly to create a match fit between the body and the flexbeam assembly.

Abstract: An aircraft is provide including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. At least one flight control computer configured to independently control the upper rotor assembly and the lower rotor assembly through a fly-by-wire control system. A plurality of sensors to detect sensor data of at least one environmental condition and at least one aircraft state data, wherein the sensors provide the sensor data to the flight control computer.

Abstract: An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with a plurality of blades rotating in a first plane and a lower rotor assembly with a plurality of blades rotating in a second plane, each of the blades having a root end, a midpoint, and a tip end. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. The blades of the upper rotor assembly and the blades of the lower rotor assembly are indexed to improve tip end clearance between pairs of tip ends in the crossing plane as the tip ends move in respective first and second sinusoidal paths.

Abstract: A rotor assembly for a rotary wing aircraft includes a rotor hub having a central axis. The rotor hub is rotatable about the central axis. A plurality of flexible structural members extend radially outwardly from the rotor hub. Each flexible structural member is substantially U-shaped having a first arm extending from the hub, a second arm extending from the hub, and an end portion connecting the first arm to the second arm at a radially outboard end of the flexible structural member. The first arm, the second arm and/or the end portion have a cross section with a height along the central axis greater than a thickness of the cross section to increase stiffness of the rotor assembly along the central axis. The rotor assembly further includes a plurality of rotor blades, each rotor blade being secured to each flexible structural member of the plurality of flexible structural members.