Abstract: The present invention includes an apparatus for preventing aircraft rollover upon a water landing comprising: a deployable first and/or second boom affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft; and a first and/or second air bladder attached to a second end of the first and/or second boom, wherein the first and/or second air bladders are configured to inflate when an aircraft lands in the water, wherein deployment of the first and second boom and air bladder prevents aircraft rollover upon water landing; or a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment; or both.

Abstract: In one aspect, there is a method of making a composite skin for a tiltrotor aircraft including providing a first skin in a mold, the first skin having a periphery defined by a forward edge, an aft edge, and outboard ends; providing a plurality of honeycomb panels having an array of large cells onto the first skin, each cell having a width of at least 1 cm; assembling the plurality of honeycomb panels along the longitudinal axis of the first skin to form a honeycomb core having an outer perimeter within the periphery of the first skin; positioning a second skin onto the honeycomb core, the second skin having an outer perimeter within the periphery of the first skin; and curing an adhesive to create a bond between the first skin, the honeycomb core, and the second skin to form a composite skin.

Abstract: An example rotating swashplate ring to rotor mast connection includes a polygon-shaped drive tube secured to the rotor mast and a gimbal joint connected between the rotating swashplate ring and the polygon-shaped drive tube, wherein the gimbal joint rotates with the rotor mast and can translate axially along the polygon-shaped drive tube.

Abstract: In one embodiment, a tiltrotor aircraft may comprise a fuselage; a biplane wing coupled to the fuselage, wherein the biplane wing comprises an upper wing structure and a lower wing structure; a plurality of tiltrotors coupled to the biplane wing; and at least one engine to power the plurality of tiltrotors.

Abstract: An aircraft having a differential rotor speed resonance avoidance system. The aircraft includes an airframe having structural elements subject to resonant vibration at critical frequencies. A thrust array is coupled to the airframe. The thrust array includes at least four rotor systems distributed about the airframe, each rotor system operable over a range of rotor speeds. A flight control system is operably associated with the thrust array and is configured to independently control the rotor speed of each rotor system. While preserving flight dynamics during flight operations, the flight control system selectively increases the rotor speed of some of the rotor systems by a speed delta and decreases the rotor speed of others of the rotor systems by the speed delta to avoid generating excitation frequencies by the rotor systems at the critical frequencies.

Abstract: A gearbox filler assembly includes a cylindrical insert attached to an interior of a port disposed within a housing of the gearbox. The cylindrical insert has a first end disposed within the port, a second end extending outward from the port and is configured to receive a detachable filler cap, a retaining lip around at least a portion of a first interior circumference proximate to the first end, and a retaining slot around at least a second interior circumference between the retaining lip and the second end. A retaining ring is detachably coupled within the retaining slot. A cylindrical baffle is detachably retained between the retaining ring and the retaining lip.

Abstract: An inlet barrier filter system for a tiltrotor aircraft comprising a filter duct extending from a filter to a filter outlet, a ram air duct extending from a ram air inlet to an engine where the filter duct connects to the ram air duct at the filter outlet, and a closure member movable between a first position blocking the ram air duct and a second position blocking the filter outlet. In use, the inlet barrier filter system provides for two mutually exclusive air flow paths, one for introducing ram air to the engine while closing off the filter and another air flow path for introducing filtered air to the engine while closing off the ram air duct.

Abstract: Embodiments are directed to an aerodynamic spinner fairing having a sidewall and one or more airflow intakes in the sidewall. The airflow intakes are closed during a first phase of flight and open during a second phase of flight. The first phase of flight may be an airplane mode for a tiltrotor aircraft, and the second phase of flight may be a helicopter mode for the tiltrotor aircraft. The airflow intakes may comprise an opening in the sidewall, and a door that is configured to move between a first position covering the opening and a second position exposing the opening to external airflow. An actuator coupled to the door may operate to move the door between the first position and the second position. One or more guide vanes within the aerodynamic spinner fairing may be configured to direct air received via the airflow intakes to provide convection cooling.

Abstract: A multirotor aircraft comprises at least three proprotors. Each proprotor has a plurality of rotor blades pivotably attached to a mast assembly. When a rotor blade pitch angle is changed for a proprotor, all rotor blades on the proprotor change to a same pitch angle. The proprotors are configured to spin freely when a power source is disengaged or fails. In various embodiments, one or more engines provides power to each proprotor, or at least one engine provides power to two or more proprotors. A rotor blade control system is configured to control a collective rotor blade pitch angle on each proprotor independently of the rotor blade pitch on the other proprotors. The rotor blade control system is configured to set a negative collective rotor blade pitch angle on an unpowered proprotor, such as in response to manual inputs by a pilot or in response to current engine conditions.

Abstract: Embodiments are directed to systems and methods for managing electrical load in an aircraft comprising a generator coupled to an aircraft engine, and a power distribution controller configured to monitor current engine operating parameters and to reduce an electrical load on the generator when the engine operating parameters reach a limit during specified aircraft operating conditions. The system may further comprise a non-essential electrical bus coupled to the generator, wherein the electrical load on the generator is reduced by disconnecting the non-essential bus from the generator. The generator may be coupled to the aircraft engine via an accessory gearbox or a transmission gearbox. The monitored current engine operating parameters comprise one or more of an engine torque, a gas generator RPM, and a temperature. The aircraft operating conditions may comprise one or more of a takeoff, a landing, or an engine failure.

Abstract: In one embodiment, an assembly fixture may include a base structure including a plurality of strands of a fiber-reinforced thermoplastic material comprising 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 base structure further comprises an anisotropic thermal expansion property based on an orientation of the plurality of reinforcement fibers within the base structure, The assembly fixture may further include a plurality of fastening structures coupled to the base structure, wherein the plurality of fastening structures is configured to fasten a plurality of components of a composite structure for assembly using a heated bonding process.

Abstract: A versatile door system for an aircraft includes forward and aft door assemblies. The forward door assembly includes a forward hingeable door hingeably coupled to the airframe proximate a forward location of an aircraft opening and a forward slidable door slidably coupled to the forward hingeable door. The aft door assembly includes an aft hingeable door hingeably coupled to the airframe proximate an aft location of the aircraft opening and an aft slidable door slidably coupled to the aft hingeable door. In a closed configuration, the forward hingeable door, the forward slidable door, the aft hingeable door and the aft slidable door are securably disposed within the aircraft opening. In operation, the forward hingeable door, the forward slidable door, the aft hingeable door and the aft slidable door are individually operable to collectively provide access to a selectable width of the aircraft opening.

Abstract: An energy absorbing landing system for an aircraft having a fuselage includes landing legs rotatably coupled to the fuselage configured to outwardly rotate when receiving a landing load having a magnitude. The energy absorbing landing system also includes an energy absorption unit coupled to the fuselage and cables coupling the energy absorption unit to the landing legs. The energy absorption unit is configured to selectively apply a resistance to the outward rotation of the landing legs via the cables based on the magnitude of the landing load, thereby absorbing the landing load when the aircraft lands.

Abstract: A pitot-static array system for a tail-sitting aircraft has a disk with a plurality of edge ports arrayed about an edge of the disk. Each of a plurality of pressure transducers is configured to measure air pressure at one of the edge ports. The edge ports are arrayed about an axis parallel to a pitch axis of the aircraft.

Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: A duct interface system and method includes a duct having a first end and a second end; a first receptacle for the first end of the duct and/or a second receptacle for the second end of the duct; and one or more first seals between the first end of the duct and the first receptacle and/or one or more second seals between the second end of the duct and the second receptacle.

Abstract: The present invention includes a span-balance pocket in a surface of a rotor blade, the span-balance pocket including an inboard surface and an outboard surface; and one or more weights disposed in the span-balance pocket to span-balance the rotor blade; and at least one of one or more retention devices to retain the one or more weights against the outboard surface of the span-balance pocket or the span-balance pocket is machined or molded into a tip block of the rotor blade.

Abstract: A method of offset load testing a tubular composite specimen with two pairs of aligned holes and having at least one defect, the method comprising: providing a testing apparatus having a pair of arms including a fixed arm and a mobile arm; securing the pair of arms using a fastener assembly in each of the two pairs of aligned holes; and moving the mobile arm to impart an offset load force to the tubular specimen. One aspect includes a method of offset load testing comprising: providing a testing apparatus having a pair of arms including a fixed arm and a mobile arm; providing a tubular composite specimen with a top portion and a bottom portion; securing the pair of arms to the top and bottom portions of the tubular composite specimen; and moving the mobile arm to impart an offset load force to the tubular composite specimen.

Abstract: An aircraft rotor system including a hub having a hub axis about which the hub is configured to rotate; a plurality of rotor blades configured to extend from the hub and rotate about the hub axis, at least one of the rotor blades rotatable about a respective pitch change axis; wherein the hub is configured to be rotated about the hub axis only by the plurality of rotor blades. Another aspect includes a method of operating the rotor system.