Abstract: An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings with first and second pylons coupled therebetween. The airframe has a longitudinal axis and a lateral axis in hover. A two-dimensional distributed thrust array is coupled to the airframe. The thrust array includes a plurality of propulsion assemblies each operable for variable speed and omnidirectional thrust vectoring. A flight control system is operable to independently control the speed and thrust vector of each of the propulsion assemblies such that in an inclined flight attitude with at least one of the longitudinal axis and the lateral axis extending out of a horizontal plane, the flight control system is operable to maintain hover stability responsive to controlling the speed and the thrust vector of the propulsion assemblies.

Abstract: In one aspect, there is a method of making a pre-cured laminate having a total number of plies in a mold, the mold having a cavity with a periphery defined by a forward edge, an aft edge, and outboard ends. The method includes selecting a first plurality of resin impregnated plies that continuously extend beyond the periphery of the cavity, the first plurality of resin impregnated plies includes at least 50 percent of the total number of plies; laying the plies in a mold; compacting the plies in a mold; and pre-curing the plies to form a pre-cured laminate, which can extend beyond the periphery of the cavity. In an embodiment, a pre-cured laminate includes a first plurality of resin impregnated plies that continuously extend beyond the periphery of the cavity.

Abstract: A quad tiltrotor aircraft has a longitudinally extending fuselage with forward and aft stations. A forward wing having first and second outboard ends extends laterally from the forward station. An aft wing having first and second outboard ends extends laterally from the aft station. First and second forward rotors are respectively coupled proximate the first and second outboard ends of the forward wing and are tiltable relative to the forward wing between vertical lift and forward thrust orientations. First and second aft rotors are respectively coupled proximate the first and second outboard ends of the aft wing and are tiltable relative to the aft wing between vertical lift and forward thrust orientations. The forward rotors are higher disk-loading rotors than the aft rotors. The aft rotors are foldable in the forward flight mode to provide extended range for the quad tiltrotor aircraft.

Abstract: A tiltrotor assembly has a central hub with a plurality of rotor blades extending therefrom and is configured to rotate about a mast axis to generate lift in a hover position. The central hub is configured to rotate about a tilt axis between the hover position and a forward-flight position such that rotation about the mast axis generates forward thrust. The central hub is surrounded by a segmented duct that includes a thin rotatable inner ring and a wide fixed outer ring. The inner ring is configured to rotate with the central hub about the tilt axis leaving the wide outer ring in a generally horizontal position.

Abstract: A tail rotor drive system (TRDS) has a shaft, a housing extending around the shaft, a mount coupled to the housing via a friction assembly and a flexure, and a bearing assembly disposed between the housing and the shaft.

Abstract: A power demand anticipation system for a rotorcraft includes an engine subsystem having an engine with a power output. The power demand anticipation system also includes one or more sensors including a cyclic control sensor. The one or more sensors are operable to detect one or more flight parameters of the rotorcraft to form sensor data including a cyclic control position. A power demand anticipation module is in data communication with the engine subsystem and the one or more sensors. The power demand anticipation module is operable to anticipate a power demand of the engine using the sensor data to form a power demand anticipation signal. The engine subsystem is operable to adjust the power output of the engine based on the power demand anticipation signal received from the power demand anticipation module.

Abstract: An aircraft has a fuselage, a first rotor assembly having a first rotor hub and first rotor blades pivotably coupled to the first rotor hub and a second rotor assembly having a second rotor hub and second rotor blades pivotably coupled to the second rotor hub. The first and second rotor blades have deployed configurations extending generally radially from the fuselage and stowed configurations extending generally parallel with the fuselage. A sequencing cam, positioned between the first and second rotor hubs, is coupled to the second rotor blades. The sequencing cam has a retracted orientation when the second rotor blades are in the stowed configuration and an extended orientation when the second rotor blades are in the deployed configuration in which the sequencing cam props support arms of the first rotor blades preventing transition of the first rotor blades from the deployed configuration to the stowed configuration.

Abstract: A method of performing structural analysis relating to a component having CAD-based geometry, refined CAD-based geometry and CAD-based FEA data associated therewith. The method includes scanning the component to obtain scan-based point cloud geometry of the component, aligning the scan-based point cloud geometry with the CAD-based geometry of the component, generating scan-based geometry of the component by refining the scan-based point cloud geometry, comparing the scan-based geometry with the refined CAD-based geometry of the component to quantify geometric differences therebetween, generating scan-based FEA geometry of the component by meshing the scan-based geometry, performing finite element analysis on the scan-based FEA geometry to obtain scan-based FEA data and comparing the scan-based FEA data with the CAD-based FEA data of the component to quantify the effect of geometric difference therebetween.

Abstract: A tail sitter aircraft includes a fuselage having a forward portion, an aft portion and a longitudinally extending fuselage axis. A main lifting surface is supported by the forward portion of the fuselage. A propulsion system is operably associated with the main lifting surface and operable to provide thrust during forward flight, vertical takeoff, hover and vertical landing. A tailboom assembly extends from the aft portion of the fuselage. The tailboom assembly includes a plurality of rotatably mounted tail arms having control surfaces and landing members wherein, in a forward flight configuration, the tail arms are radially retracted to reduce tail surface geometry and provide yaw and pitch control with the control surfaces and, wherein, in a landing configuration, the tail arms are radially extended relative to one another about the fuselage axis to form a stable ground contact base with the landing members.

Abstract: A latch system includes an actuation module having first and second actuation mechanisms. The first actuation mechanism includes a first handle, a lock tab and an inner rod coupled together. The second actuation mechanism includes at least one second handle, a conversion block and an outer rod coupled together with the outer rod and the conversion block each having a slot. At least one latch module has a retractable latch. A control cable connects the conversion block and the latch module such that rotation of the conversion block in a first direction retracts the latch. A lock is operably engagable with the lock tab to selectively allow and prevent rotation of the inner rod. Rotation of the inner rod in the first direction rotates the conversion block. Rotation of the outer rod in the first direction rotates the conversion block without rotating the inner rod.

Abstract: A latch system includes an actuation module having first and second actuation mechanisms. The first actuation mechanism includes a first handle coupled to a locking rod having an end slot and an oppositely disposed rod insert. The second actuation mechanism includes at least one second handle, a conversion block and an outer rod coupled together. The outer rod has an open end and a slot. At least one latch module has a retractable latch. A control cable connects the conversion block and the latch module such that rotation of the conversion block in a first direction retracts the latch. A lock is operably engagable with the end slot to selectively allow and prevent rotation of the inner rod. Selective rotation of the locking rod in the first direction rotates the conversion block. Rotation of the outer rod in the first direction rotates the conversion block without rotating the locking rod.

Abstract: A mounting assembly for coupling an accessory to a frame including a base configured to be coupled to the frame; the base having a hollow portion; the hollow portion including a receiving end including a tapered socket; an internal interlocking portion adjacent to the tapered socket; and a securing end opposite from the receiving end; a shaft configured to be connected to an accessory at a first end and received in the hollow portion of the base in an engaged position, the shaft including a tapered boss adjacent to the first end, the tapered boss configured to engage the tapered socket; an external interlocking portion adjacent to the tapered boss configured to engage the internal interlocking portion; and a second end opposite from the first end, the second end including a threaded surface; wherein when the shaft is in an engaged position, the shaft is static in the hollow portion.

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: A system and algorithm-based method of determining engine health and assuring available propulsion power based on historical data reflecting the individual engine's unique performance “fingerprint.

Abstract: A tiltrotor aircraft includes a fuselage supporting first and second wings each having an outboard end. First and second nacelles are respectively coupled to the outboard ends of the first and second wings. The first and second nacelles each have an outboard end. First and second wing extensions are rotatably coupled, respectively, to the outboard ends of the first and second nacelles. First and second actuators are operable to respectively move the first and second wing extensions to dampen a mode of the first and second wings, thereby stabilizing the tiltrotor aircraft.

Abstract: In some embodiments, a rotorcraft includes a fuselage, a tailboom, a drive system and a variable thrust cross-flow fan system. The cross-flow fan system includes a cross-flow fan assembly that is mechanically coupled to a drive shaft and operable to rotate with the drive shaft about a longitudinal axis. The cross-flow fan assembly includes first and second driver plates having a plurality of blades rotatably mounted therebetween. The blades are disposed radially outwardly from the longitudinal axis and have a generally circular path of travel when the cross-flow fan assembly rotates about the longitudinal axis. The blades are moveable between a plurality of pitch angle configurations. A control assembly is coupled to the blades. The control assembly is operable to change the pitch angle configuration of the blades to generate variable thrust at a substantially constant rotational speed of the cross-flow fan assembly.

Abstract: A propulsion system includes an engine disposed within a fuselage, a first gearbox coupled to the engine, a wing member having an upper wing skin and torque box formed by a first rib, a second rib, a first spar and second spar, a drive shaft coupled to the first gearbox and disposed within the wing member, a second gear box coupled to the drive shaft and disposed outboard from the second rib or inboard from the first rib, and a rotatable proprotor coupled to the second gear box. The rotatable proprotor includes a plurality of rotor blades, a rotor mast having a mast axis of rotation, and a proprotor gearbox coupled to the rotor mast. The proprotor gearbox is rotatable about a conversion axis, which intersects with the mast axis of rotation at a point within a central region of the torque box and above the upper wing skin.

Abstract: In accordance with an embodiment, a method of operating a rotorcraft includes receiving a first sensor value comprising a first coarse resolution portion and a first fine resolution portion, receiving a second sensor value comprising a second coarse resolution portion and a second fine resolution portion, and determining that the second coarse resolution portion corresponds with the second fine resolution portion when a difference between the second sensor value and the first sensor value is within a first threshold.

Abstract: A mounting assembly for mounting a portion of an engine exhaust duct in an opening of an airframe panel aircraft, including a peripheral flange disposed on the portion of the exhaust duct, and at least one mounting member having an outer peripheral flange portion for connection to the airframe panel and having an inner peripheral flange portion with at least one compliant isolator member to receive the peripheral flange of the exhaust duct in a manner that suspends the exhaust duct in the opening away from the airframe panel and accommodates thermal expansion and contraction of the exhaust duct relative to the airframe panel. Embodiments include a method of mounting an engine exhaust duct in an opening of an outer airframe panel of an aircraft.

Abstract: Systems and methods for testing and validating fatigue life of a complex structure includes determining flight loads acting on the complex structure, identifying fatigue sensitive points in the complex structure in response to the flight loads acting on the complex structure, grouping the fatigue sensitive points into a plurality of families, selecting at least one representative fatigue sensitive point from each family, creating at least one detail specimen that replicates the representative fatigue sensitive point from each family, fatigue testing the detail specimens, and comparing results determined in response to fatigue testing the detail specimens to the determined flight loads.