Abstract: Embodiments are directed to a tiltrotor aircraft having a wing, a proprotor pivotably mounted on the wing, and a downstop striker attached to the proprotor using a load pin, wherein the load pin is configured to generate an output signal representing a force between the proprotor and the wing. A downstop mounted on the wing is aligned to be in contact with the downstop striker when the proprotor is in a horizontal position. A conversion actuator moves the proprotor between a horizontal position and vertical position. A flight control computer is coupled to the output signal from the load pin and configured to control the conversion actuator, wherein the flight control computer is configured to cause the conversion actuator to increase the force if the force is less than a first selected preload value or to decrease the force if the force is greater than a second selected preload value.

Abstract: A pylon conversion actuator, for use in tiltrotor aircraft, that converts the tiltrotor between hover flight mode and forward flight mode. Pylon conversion actuator selectively retracts and extends between a retracted position to an extended position. Pylon conversion actuator includes an extendable arm, a motor, and an actuator platform.

Abstract: A compliant tail structure for a rotorcraft having rotating components and a fuselage. The tail structure includes a tail assembly having first and second oppositely disposed tail members. A tail joint connects the tail assembly to an aft portion of the fuselage. The tail joint includes at least four tail mounts configured to establish a nodding axis for the tail assembly. At least two of the tail mounts are resilient tail mounts that are configured to establish a nodding degree of freedom for the tail assembly relative to the fuselage about the nodding axis, thereby detuning dynamic fuselage responses from excitation frequencies generated by the rotating components.

Abstract: Embodiments are directed to a tiltrotor aircraft having a wing, a proprotor pivotably mounted on the wing, and a downstop striker attached to the proprotor using a load pin, wherein the load pin is configured to generate an output signal representing a force between the proprotor and the wing. A downstop mounted on the wing is aligned to be in contact with the downstop striker when the proprotor is in a horizontal position. A conversion actuator moves the proprotor between a horizontal position and vertical position. A flight control computer is coupled to the output signal from the load pin and configured to control the conversion actuator, wherein the flight control computer is configured to cause the conversion actuator to increase the force if the force is less than a first selected preload value or to decrease the force if the force is greater than a second selected preload value.

Abstract: A compliant tail structure for a rotorcraft having rotating components and a fuselage. The tail structure includes a tail assembly having first and second oppositely disposed tail members. A tail joint connects the tail assembly to an aft portion of the fuselage. The tail joint includes at least four tail mounts configured to establish a nodding axis for the tail assembly. At least two of the tail mounts are resilient tail mounts that are configured to establish a nodding degree of freedom for the tail assembly relative to the fuselage about the nodding axis, thereby detuning dynamic fuselage responses from excitation frequencies generated by the rotating components.

Abstract: A pylon conversion actuator, for use in tiltrotor aircraft, that converts the tiltrotor between hover flight mode and forward flight mode. Pylon conversion actuator selectively retracts and extends between a retracted position to an extended position. Pylon conversion actuator includes an extendable arm, a motor, and an actuator platform.

Abstract: A tiltrotor aircraft includes a propulsion system with a fixed engine and a rotatable proprotor. The engine is located below the wing of the tiltrotor aircraft, and the rotatable proprotor assembly is mounted on the top surface of the wing. The engine and proprotor assembly are connected via a series of one or more gearboxes that route the engine output from the engine to the proprotor.

Abstract: A compliant tail structure for a rotorcraft having rotating components and a fuselage. The tail structure includes a tail assembly having first and second oppositely disposed tail members. A tail joint connects the tail assembly to an aft portion of the fuselage. The tail joint includes at least four tail mounts configured to establish a nodding axis for the tail assembly. At least two of the tail mounts are resilient tail mounts that are configured to establish a nodding degree of freedom for the tail assembly relative to the fuselage about the nodding axis, thereby detuning dynamic fuselage responses from excitation frequencies generated by the rotating components.

Abstract: A propulsion and lift system of a tiltrotor aircraft includes a wing having an outboard end, a wing tip assembly having an inboard end, a fixed nacelle coupled to the wing tip assembly and a wing-nacelle splice assembly having inboard and outboard sides. The inboard side of the wing-nacelle splice assembly is coupled to the outboard end of the wing, and the outboard side of the wing-nacelle splice assembly is coupled to the inboard end of the wing tip assembly, thereby coupling the fixed nacelle to the wing.

Abstract: A wing assembly for an aircraft includes a torque box sleeve having an open end and a plurality of integral sides including leading, aft, top and bottom sides that jointlessly form a continuous surface having a generally airfoil shape. The wing assembly includes an internal support subassembly having a plurality of ribs coupled to a central spar. The internal support subassembly is formed into a single component outside the torque box sleeve and inserted into the open end of the torque box sleeve as the single component. The internal support subassembly is coupled to an interior of the torque box sleeve.

Abstract: A tiltrotor aircraft includes a propulsion system with a fixed engine and a rotatable proprotor. The engine is located on the top surface of the wing of the tiltrotor aircraft, and the rotatable proprotor assembly is also mounted on the top surface of the wing. The engine and proprotor assembly are connected via a series of one or more gearboxes that route the engine output from the engine to the proprotor.

Abstract: A torque box rib includes an upper rib cap configured to be coupled to an upper skin of a wing, a lower rib cap configured to be coupled to a lower skin of the wing, a forward post configured to be coupled to a forward spar of the wing, an aft post configured to be coupled to an aft spar of the wing, and a rib web configured to be coupled to the upper rib cap, the lower rib cap, the forward post, and the aft post.

Abstract: A wing assembly for an aircraft includes a torque box sleeve having an open end and a plurality of integral sides including leading, aft, top and bottom sides that jointlessly form a continuous surface having a generally airfoil shape. The wing assembly includes an internal support subassembly having a plurality of ribs coupled to a central spar. The internal support subassembly is formed into a single component outside the torque box sleeve and inserted into the open end of the torque box sleeve as the single component. The internal support subassembly is coupled to an interior of the torque box sleeve.

Abstract: A compliant tail structure for a rotorcraft having rotating components and a fuselage. The tail structure includes a tail assembly having first and second oppositely disposed tail members. A tail joint connects the tail assembly to an aft portion of the fuselage. The tail joint includes at least four tail mounts configured to establish a nodding axis for the tail assembly. At least two of the tail mounts are resilient tail mounts that are configured to establish a nodding degree of freedom for the tail assembly relative to the fuselage about the nodding axis, thereby detuning dynamic fuselage responses from excitation frequencies generated by the rotating components.

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: A propulsion and lift system of a tiltrotor aircraft includes a wing having an outboard end, a wing tip assembly having an inboard end, a fixed nacelle coupled to the wing tip assembly and a wing-nacelle splice assembly having inboard and outboard sides. The inboard side of the wing-nacelle splice assembly is coupled to the outboard end of the wing, and the outboard side of the wing-nacelle splice assembly is coupled to the inboard end of the wing tip assembly, thereby coupling the fixed nacelle to the wing.

Abstract: A wing airframe for a wing of a tiltrotor aircraft includes a wing airframe core assembly and a wing skin assembly disposed on the wing airframe core assembly. The wing skin assembly includes a lower wing skin assembly disposed on the bottom side of the wing airframe core assembly. The tiltrotor aircraft includes a fuselage underneath the wing. The lower wing skin assembly has one or more buckle zones outboard of the fuselage. The buckle zones are locally susceptible to buckling in response to an impact of the tiltrotor aircraft, thereby protecting the fuselage from being crushed by the wing.

Abstract: A propulsion and lift system of a tiltrotor aircraft includes a wing having an outboard end, a wing tip assembly having an inboard end, a fixed nacelle coupled to the wing tip assembly and a wing-nacelle splice assembly having inboard and outboard sides. The inboard side of the wing-nacelle splice assembly is coupled to the outboard end of the wing, and the outboard side of the wing-nacelle splice assembly is coupled to the inboard end of the wing tip assembly, thereby coupling the fixed nacelle to the wing.

Abstract: An adhesive joint for an aircraft includes a first aircraft component having a first surface forming one or more isolation grooves, a second aircraft component having a second surface and an adhesive forming a bondline between the first and second surfaces to bond the first aircraft component to the second aircraft component. The adhesive substantially fills the one or more isolation grooves to form at least one disbond arrest boundary. The at least one disbond arrest boundary is operable to prevent a disbond in the bondline from traversing therethrough, thereby preventing the disbond from propagating along the bondline across the at least one disbond arrest boundary.

Abstract: A tiltrotor aircraft includes a propulsion system with a fixed engine and a rotatable proprotor. The engine is located on the top surface of the wing of the tiltrotor aircraft, and the rotatable proprotor assembly is also mounted on the top surface of the wing. The engine and proprotor assembly are connected via a series of one or more gearboxes that route the engine output from the engine to the proprotor.