Abstract: In one embodiment, a method includes fastening a plurality of components of a composite structure in an assembly fixture, wherein the assembly fixture comprises a plurality of strands of a fiber-reinforced thermoplastic material, wherein the fiber-reinforced thermoplastic material comprises a thermoplastic embedded with a plurality of reinforcement fibers, wherein the plurality of reinforcement fibers is aligned within each strand of the plurality of strands, and wherein the assembly fixture further comprises an anisotropic thermal expansion property based on an orientation of the plurality of reinforcement fibers within the assembly fixture; and heating the assembly fixture in an autoclave to bond the plurality of components of the composite structure.

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: A technique is performed on a vehicle having a lithium battery and a temperature control apparatus. The technique involves receiving a temperature reading from temperature sensing circuitry. The technique further involves performing a comparison operation that compares the temperature reading from the temperature sensing circuitry to a target temperature range. The technique further involves, in response to a result of the comparison operation indicating that the temperature reading is outside the target temperature range, automatically providing electric power from an external battery charger to the temperature control apparatus of the vehicle. The external battery charger is distinct and separate from the vehicle. Additionally, the temperature control apparatus adjusts the temperature of the lithium battery of the vehicle in response to the electric power automatically provided from the external battery charger (e.g.

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: In one embodiment, a method may comprise heating a composite material into a viscous form, wherein the composite material comprises a thermoplastic and a plurality of reinforcement fibers, wherein the plurality of reinforcement fibers is randomly arranged within the thermoplastic. The method may further comprise extruding a plurality of strands of the composite material, wherein extruding the plurality of strands causes the plurality of reinforcement fibers within each strand to align. The method may further comprise arranging the plurality of strands of the composite material to form a mold tool, wherein the mold tool is configured to mold a composite structure at a heated temperature, and wherein the mold tool comprises an anisotropic thermal expansion property, wherein the anisotropic thermal expansion property is based on an orientation of the plurality of reinforcement fibers within the mold tool.

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 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: 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: A method of controlling a tail rotor system includes pivoting a swashplate of the tail rotor system about an axis passing through a diameter of the swashplate. Pivoting the swashplate causes a first linkage of a first pair of linkages coupled between the swashplate and a collective crosshead to move in a first direction and a second linkage of the first pair of linkages coupled between the swashplate and the collective crosshead to move in a second direction that is opposite the first direction. The movement of the first and second linkages causes a plane of rotation of a pair of rotors of the tail rotor system to cant relative to a centerline of a mast of the tail rotor system. A tail rotor system is also disclosed.

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 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: 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: One embodiment is a system including a component for installation on a vehicle comprising a central maintenance computer (“CMC”); a configuration/maintenance module (“CMM”) associated with the component and including memory for storing component information, a sensor for detecting a condition and generating data indicative thereof; a microprocessor for processing the sensor data and updating the component information with the processing results; and a communications interface between the CMM and the CMC. The system further includes a remaining useful life (“RUL”) module associated with the component that periodically updates an RUL, the RUL module periodically updating an RUL value for the component and communicating the updated RUL value to the CMM for storage in the memory. The CMC communicates with the CMM to update the component information included in the memory based on information input to the CMC by a user or changes in a condition of the vehicle.

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.