Abstract: An aircraft is provided and includes an airframe, a blade disk, which is rotatable relative to the airframe, including a plurality of rotor blades, a rotor shaft disposed to drive rotation of the blade disk relative to the airframe and a pitching of each of the rotor blades about corresponding pitch axes and a rotor assembly configured to form couplings by which each of the rotor blades is coupled to the rotor shaft. The rotor assembly includes a composite laminate arranged to resolve loading associated with the couplings in-plane of the composite laminate.

Abstract: A pin configured for use in a rotor blade movable between an aligned position and a folded position and having a rotor blade airfoil contour is provided including a cylindrical body configured to couple a first section and a second section of the rotor blade when the rotor blade is in the aligned position. A handle is mounted to an end of the cylindrical body and has an airfoil contour complementary to the rotor blade airfoil contour. The handle is movable between an open position and a closed position. When the handle is in the closed position, the handle is flush with an adjacent portion of the rotor blade. When the handle is in the open position, the handle is accessible to pull the cylindrical body from the first and second section s of the rotor blade.

Abstract: A swashplate apparatus is provided and includes a first swashplate including outer and inner bodies and an intermediate portion defining a major groove between the outer and inner bodies, a second swashplate disposable in the major groove to be rotatable relative to the first swashplate, the second swashplate including an interior facing surface radially separated from the inner body to define a minor groove and defining a recess in which the rod end is disposable, a connector disposable in the recess to pivotably couple the rod end to the second swashplate and a plate element disposable in the minor groove and affixable to the interior facing surface of the second swashplate and the connector.

Abstract: A control link disposed to transfer rotor shaft rotation from an elongate element rotatable with a shaft to a rotatable element is provided and includes a structure terminating at a first end thereof as a mating element, which is securable to the elongate element such that the elongate element is rotatable about an axis defined through the mating element and such that a moment reaction in opposition to structure rotation about the elongate element is generated and a rod coupled to the rotatable element being and configured to be coupled to a second end of the structure at variable distances relative to the rotatable element.

Abstract: A control link disposed to transfer rotor shaft rotation from an elongate element rotatable with a shaft to a rotatable element is provided and includes a structure terminating at a first end thereof as a mating element, which is securable to the elongate element such that the elongate element is rotatable about an axis defined through the mating element and such that a moment reaction in opposition to structure rotation about the elongate element is generated and a rod coupled to the rotatable element being and configured to be coupled to a second end of the structure at variable distances relative to the rotatable element.

Abstract: An aircraft rotor head is provided and includes a rotor hub including a central portion and radial arms extending outwardly from the central portion, blade retention yokes, each blade retention poke being pivotably coupled to a corresponding one of the radial arms at one end and to a corresponding blade at another end and a lag restraint star rotatable about and translatable along the central portion. The lag restraint star is coupled to each of the blade retention yokes to facilitate uniform blade lead/lag and uniform blade coning.

Abstract: A constant velocity drive includes a drive ring and a driven ring positioned around the drive ring. Drive links extend from the drive ring to the driven ring to transfer torque applied at the drive ring to the driven ring. Elastomeric bearings are positioned at the driven ring to transfer torque from a drive link of the plurality of drive links to the driven ring. Each elastomeric bearing includes both spherical bearing elements and planar bearing elements to allow for tilt of an axis of rotation of the driven ring with respect to an axis of rotation of the drive ring while ensuring a constant rotational velocity of the driven ring with respect to the rotational velocity of the drive ring.

Abstract: A rotor assembly includes a rotor shaft rotatable about a rotor axis and a plurality of rotor blades operably connected to the rotor shaft. A rotor control assembly has a plurality of substantially concentric control tubes extending through the rotor shaft. Each control tube of the plurality of control tubes is operably connected to a rotor blade of the plurality of rotor blades such that movement of one or more of the control tubes of the plurality of control tubes along the rotor axis effects a pitch change in one or more rotor blades of the plurality of rotor blades. A method of controlling pitch of a plurality of rotor blades of a rotor assembly includes locating a plurality of concentric control tubes inside of a rotor shaft of the rotor assembly capable of changing a pitch of one or more of the rotor blades.

Abstract: A swash plate assembly includes a rotationally stationary swash plate and rotational swash plate which rotates relative to the rotationally stationary swash plate through a bearing system. Each servo control rod is attached to the swash plate assembly to communicate control inputs thereto through a respective servo lug. Each servo lug defines a servo pivot point off an in-line plane inboard of the bearing system. As the servo lugs extend below the rotationally stationary swash plate, a relatively uncomplicated attachment arrangement is facilitated which provides for redundant locking features at a highly inspectable location which simplifies maintenance and increased safety. By locating the servo pivot point just inboard of the bearing system, an exceeding compact load path is defined thereby.

Abstract: A rotor assembly includes a rotor shaft rotatable about a rotor axis and a plurality of rotor blades operably connected to the rotor shaft. A rotor control assembly has a plurality of substantially concentric control tubes extending through the rotor shaft. Each control tube of the plurality of control tubes is operably connected to a rotor blade of the plurality of rotor blades such that movement of one or more of the control tubes of the plurality of control tubes along the rotor axis effects a pitch change in one or more rotor blades of the plurality of rotor blades. A method of controlling pitch of a plurality of rotor blades of a rotor assembly includes locating a plurality of concentric control tubes inside of a rotor shaft of the rotor assembly capable of changing a pitch of one or more of the rotor blades.

Abstract: A rotor assembly having a rotor hub, a plurality of yokes, and a plurality of swing arms is provided. The yoke depending from the rotor hub. Each swing arm is movably positioned on the rotor hub for rotation between an unlocked position and a locked position. The yokes are freely movable about a pitch axis and a lead/lag axis when the swing arms are in the unlocked position and the yokes are locked in a predetermined pitch position and a predetermined lead/lag position when the swing arms are in the locked position.

Abstract: A rotor hub fairing system includes an upper hub fairing, a lower hub fairing and a shaft fairing therebetween. The rotor hub fairing system is attached to the counter-rotating, coaxial rotor system through a bearing arrangement such that the shaft fairing may be positioned at an azimuthal position about the main rotor axis of rotation relative the airframe by a de-rotation system. The de-rotation system controls the position of the shaft fairing about the axis of rotation such that the shaft fairing is prevented from rotating freely in unison with either shaft as may otherwise result during some flight regimes.

Abstract: A de-rotation system includes a first ring gear defined about an axis of rotation, a second ring gear defined about the axis of rotation and a gear set in meshing engagement with the first ring gear and the second ring gear to control a position of a housing about the axis of rotation.

Abstract: A de-rotation system includes a first ring gear defined about an axis of rotation, a second ring gear defined about the axis of rotation and a gear set in meshing engagement with the first ring gear and the second ring gear to control a position of a housing about the axis of rotation.

Abstract: One embodiment of a main rotor pitch control rod subassembly includes an upper rod end segment having a bearing subassembly, a lower rod end segment having a bearing subassembly, an eccentric bushing disposed in rotatable combination with the upper rod end segment bearing subassembly for varying the axial length of the pitch control rod subassembly, a composite central body structure interposed between the upper and lower end segments, a composite strap member wrapped around and secured in combination with the lower end segment bearing subassembly, the composite central body structure, and the upper end segment bearing subassembly, eccentric bushing combination, a composite overwrap overlayed in combination with the composite strap member, a locking key member and a clamp-up bolt for clamping the composite strap member in tensioned combination with the locking key member, and a locking bolt.

Abstract: One preferred embodiment of a rotary viscous damper that provides damping force constancy over the operating temperature range of a viscous working fluid includes a damper housing defining a stationary conical damping surface, a shaft member rotatably mounted in the damper housing, a rotor member having a rotating conical damping surface, a temperature compensation mechanism, and a bias spring. The stationary and rotating conical damping surfaces in opposed combination define the shear gap of the damper. The rotor member is mounted in combination with the shaft member, and is axially displaceable with respect thereto. The bias spring provides a constant spring force acting on the rotor member to axially position the rotor member to establish the baseline shear gap of the damper. The temperature compensation mechanism is mounted in compressive engagement with the rotor member and exerts a temperature-dependent biasing force thereagainst in opposition to the constant spring force.

Abstract: A blade retention pin system is operative to secure the blade cuff of a main rotor blade of a helicopter in combination with a spindle assembly of the main rotor hub assembly for main rotor assembly operations and is readily reconfigurable to accommodate blade folding operations. The blade retention pin system includes first and second pin assemblies, each pin assembly including a retainer pin and a handle subassembly, which includes a retainer member and a spring member in superposed abutting combination, pivotably mounted in combination therewith. The first pin assembly includes, in addition, a safety pin subassembly secured in combination therewith. Each retainer pin is inserted into aligned apertures of the blade cuff and spindle assembly and locked in place by pivoting the handle subassembly from an unlocked to a locked position wherein the retainer member engages the retainer pin and the spring member is biased onto the retainer pin to abuttingly engage the retainer member.

Abstract: A flexbeam helicopter rotor having an improved snubber-vibration damper for positioning the flexbeam spar relative to the torque tube, wherein the snubber-damper is an elastomeric bearing having a spherical and a flat portion, and whose laminates are continuous, selectively preloaded and of selected material to provide increased fatigue life, size reduction, reduced laminate stress concentration, and reduced critical design stress in the snubber-vibration damper.

Abstract: Mechanical collective pitch control system for a circulation control rotor system aircraft utilizing an axially moveable pneumatic system plenum 32 in the collective pitch control system.