Abstract: A resolver assembly for a ducted-rotor aircraft is configured to detect and measure rotation of a spindle of the aircraft. The resolver assembly includes first and second gear-driven resolvers. The first and second resolvers are coupled about a shared pivot axis and are independently pivotable about the pivot axis to maintain engagement of the first and second resolvers with the spindle of the aircraft. The resolver assembly is configured such that the first and second resolvers are biased toward the spindle. The input shafts of the first and second resolvers are spaced from the pivot axis through respective first and second distances that extend outward from the pivot axis along respective first and second radial directions. The first distance is equal to the second distance and the first radial direction is not coincident with the second radial direction.

Abstract: A method of repairing an aircraft component having a structural core surrounded by an exterior skin of composite material includes removing damaged material from the component to create a cavity therein that exposes an undamaged portion of the structural core, applying a septum comprising composite material to the undamaged portion of the structural core within the cavity such that an orientation of fibers in the septum matches an orientation of fibers in the exterior skin, placing a repair core onto the septum in the cavity such that cells of the repair core are in alignment with cells of the undamaged portion of the structural core, inserting a shim into the cavity along a perimeter of the repair core, applying a patch that covers the cavity to the exterior skin, and co-curing the septum, shim, and patch to bond the repair core in place within the cavity.

Abstract: An exemplary length adjustable link includes a tube having an internal bore and internal surface, a first rod end having a first shaft disposed in a first end of the internal bore, a second rod end having a second shaft disposed in a second end of the internal bore, and a member threadably connecting the first rod end to the second rod end.

Abstract: An exemplary tiltrotor aircraft with a hybrid drive system includes a first propulsion system having a first engine and a first supplemental driver operably coupled to a first proprotor that is operable between a helicopter mode and an airplane mode and a second propulsion system having a second engine and a second supplemental driver operably coupled to a second proprotor that is operable between a helicopter mode and an airplane mode.

Abstract: Embodiments are directed to a double Hooke's joint gimbal in a rotor system. An upper Hooke's joint has four arms extending radially outward to define first and second axes, and a lower Hooke's joint has four arms extending radially outward to define third and fourth axes. A pair of connectors couple the upper Hooke's joint and the lower Hooke's joint. A first set of bearings are positioned between arms on the upper and lower Hooke's joints and the connectors. The first set of bearings comprise an elastomer, such as elastomeric journal bearings. The upper Hooke's joint is coupled to a yoke and rotor blades by a driver assembly that allows rotor blade flapping. The lower Hooke's joint is coupled to and driven by a mast. A spherical bearing allows the upper Hooke's joint to move laterally along the mast.

Abstract: An example of a ceramic bearing system includes a shaft comprising two radially extending shoulders that define a channel therebetween, a first tolerance ring disposed in the channel of the shaft, and a bearing assembly comprising a ceramic bearing. The bearing assembly is positioned around the first tolerance ring and has an axial length that is longer than an axial length of the first tolerance ring.

Abstract: Embodiments are directed to a rotor hub assembly comprising a yoke configured to attach rotor blades thereto, a single Hooke's joint configured to attach to, and transmit forces between, a mast and the yoke, and a spherical bearing coupled between the yoke and the mast. Two pillow blocks couple the single Hooke's joint to the yoke. An adapter sleeve is attached to the pillow blocks and is positioned to surround the spherical bearing. The adapter sleeve extends between the single Hooke's joint and the mast. A hub lock extension is attached to the yoke. The hub lock extension is configured to receive a hub lock that prevents gimballing of the yoke when engaged.

Abstract: An aircraft includes a wing positioned below a vertical rotor, the wing extending in a transverse direction to a wingtip having an outboard face, and a turbulence feature located on the wingtip and oriented to induce turbulence in the rotor downwash flowing across the outboard face in a direction from a top surface of the wing to a bottom surface of the wing.

Abstract: A vertical-takeoff-and-landing (“VTOL”) aircraft including a non-VTOL aircraft equipped for forward takeoff and flight and a modular boom system interoperably coupled to the non-VTOL aircraft. The modular boom system includes a first modular boom and a second modular boom. The first modular boom includes a first rocket-turbine engine. The first modular boom is mounted to a first wing of the non-VTOL aircraft. The second modular boom includes a second rocket-turbine engine. The second modular boom is mounted to a second wing of the non-VTOL aircraft.

Abstract: An exemplary tail rotor includes a first blade assembly configured to rotate in a first direction about an axis of rotation and a second blade assembly configured to rotate in a second direction about the axis of rotation.

Abstract: An example of a concentric probe includes an outer shroud having a bore that extends through the outer shroud, an inner shroud located within the outer shroud and having a bore that extends through the inner shroud, the inner shroud joined to the outer shroud via brazing, an annulus defined by a space between the inner shroud and a wall of the bore of the outer shroud, a plenum defined by a space between the inner shroud and the wall of the bore of the outer shroud, the plenum being in fluid communication with the annulus, and a transducer disposed within inner shroud.

Abstract: An exemplary method to determine an airspeed and an angle of attack of a propeller powered vehicle includes determining the power delivered to the propeller, the air density, a propeller power coefficient, an advance ratio for the propeller, and the airspeed using the advance ratio and determining the angle of attack using the airspeed.

Abstract: Embodiments are directed to a propulsion assembly for an aircraft. The propulsion assembly comprises a mast, a hub assembly coupled to the mast and having a gimballing degree of freedom relative to the mast, the hub assembly having an inner hub wall spaced part from the mast, a gimbal lock positioned about the mast, the gimbal lock configured to fit between the inner hub wall and the mast in an engaged position, and an over-center locking mechanism coupled to the gimbal lock. The gimbal lock is movable between a disengaged position and the engaged position relative to the hub assembly. The gimbal lock enables the gimballing degree of freedom in the disengaged position and disables the gimballing degree of freedom in the engaged position. The over-center locking mechanism is configured to move the gimbal lock between the engaged position and the disengaged position.

Abstract: An exemplary cushion for a fuel system is constructed of a lattice structure formed of a material that is substantially nonabsorbent of fuel and has a network of nodes and beams defining cells, an exterior surface of the lattice structure is configured to be oriented toward a fuel cell and an interior surface of the lattice structure is configured to fit to a mounting surface.

Abstract: An exemplary adjustable length link includes a first rod end having a body with a threaded socket, a second rod end having a threaded shaft and a sleeve having external threads cooperative with the threaded socket and a bore with internal threads cooperative with the threaded shaft.

Abstract: A system for deploying and retrieving a parasite aircraft includes a parasite aircraft with a dock and a carrier aircraft that includes a maneuverable capture device tethered to the carrier aircraft via a cable. The maneuverable capture device includes a plurality of rotors and is configured to dock in the dock of the parasite aircraft. A method of deploying a parasite aircraft includes positioning a parasite aircraft on a loading surface; positioning a carrier aircraft above the parasite aircraft; releasing, from the carrier aircraft, a maneuverable capture device comprising a plurality of rotors; securing the maneuverable capture device to a dock positioned on the parasite aircraft; lifting, via a cable secured at a first end to the carrier aircraft and at a second end to the maneuverable capture device, the parasite aircraft with the carrier aircraft; and releasing the parasite aircraft from the maneuverable capture device.

Abstract: A door roller includes a carriage member comprising a plurality of bores, and a plurality of roller assemblies connected to the carriage member, each roller assembly of the plurality of roller assemblies including a pivot bearing rotatably disposed within a bore of the plurality of bores and a pair of rollers coupled to the pivot bearing. Each wheel assembly is configured to pivot relative to the carriage member.

Abstract: A system and method for preventing a maximum asymmetric condition between pylon tilt angles due to a degraded pylon in a fly-by-wire tiltrotor aircraft during transitions between airplane mode and helicopter mode includes a conversion system for imparting movement on a right and left pylon. A flight control computer is operatively connected to a set of transducers for measuring pylon angles. The flight control computer is further connected to a set of actuators which are attached to each pylon. The flight control computer receives flight dynamics input from the set of transducers and/or the pilot and sends pylon command to the set of actuators. The conversion system measures the difference between the pylon angles during the transition and provides a pylon command adjustment if the difference exceeds a preset threshold.

Abstract: An exemplary aircraft includes a wing positioned below a vertical rotor, the wing extending to an outboard end, and an anhedral winglet extending from the outboard end through an angular transition to a tip, the anhedral winglet having an external surface exposed to the rotor downwash and the external surface is contoured to generate local wing lift in response to the rotor downwash.

Abstract: An exemplary ducted fan with an optimized stator includes a duct surrounding a rotor hub from which blades radially extend and the stator having a stator span extending horizontally across an inside diameter of the duct, the stator having a stator chord extending from a leading edge to a trailing edge, wherein a length of the stator chord varies across the stator span.