Abstract: A tail rotor assembly coupled to a tailboom of a helicopter includes a tail rotor gearbox having top, bottom and aft sides and a shroud surrounding the tail rotor gearbox. The shroud includes a shroud airframe having top and bottom portions. The tail rotor assembly includes a tail rotor gearbox support assembly configured to support the tail rotor gearbox within the shroud. The tail rotor gearbox support assembly includes a support column coupling the aft side of the tail rotor gearbox between the top and bottom portions of the shroud airframe, an upper support crossbar coupling the top side of the tail rotor gearbox between the support column and the tailboom airframe and a lower support crossbar coupling the bottom side of the tail rotor gearbox between the support column and the tailboom airframe.

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 tail rotor assembly coupled to a tailboom of a helicopter includes a tail rotor gearbox having top, bottom and aft sides and a shroud surrounding the tail rotor gearbox. The shroud includes a shroud airframe having top and bottom portions. The tail rotor assembly includes a tail rotor gearbox support assembly configured to support the tail rotor gearbox within the shroud. The tail rotor gearbox support assembly includes a support column coupling the aft side of the tail rotor gearbox between the top and bottom portions of the shroud airframe, an upper support crossbar coupling the top side of the tail rotor gearbox between the support column and the tailboom airframe and a lower support crossbar coupling the bottom side of the tail rotor gearbox between the support column and the tailboom airframe.

Abstract: A propulsion and lift system for an aircraft includes a wing having an outboard end and a pylon assembly coupled to the outboard end of the wing. The propulsion and lift system also includes a wing extension rotatably coupled to the outboard end of the pylon assembly. The wing extension is rotatable between a flight position in a flight mode and a stow position in a storage mode. The wing extension folds inboard in the stow position, thereby reducing a wingspan of the aircraft in the storage mode.

Abstract: A tail rotor assembly coupled to a tailboom of a helicopter includes a tail rotor gearbox having top, bottom and aft sides and a shroud surrounding the tail rotor gearbox. The shroud includes a shroud airframe having top and bottom portions. The tail rotor assembly includes a tail rotor gearbox support assembly configured to support the tail rotor gearbox within the shroud. The tail rotor gearbox support assembly includes a support column coupling the aft side of the tail rotor gearbox between the top and bottom portions of the shroud airframe, an upper support crossbar coupling the top side of the tail rotor gearbox between the support column and the tailboom airframe and a lower support crossbar coupling the bottom side of the tail rotor gearbox between the support column and the tailboom airframe.

Abstract: A tail rotor assembly coupled to a tailboom of a helicopter includes a tail rotor gearbox having top, bottom and aft sides and a shroud surrounding the tail rotor gearbox. The shroud includes a shroud airframe having top and bottom portions. The tail rotor assembly includes a tail rotor gearbox support assembly configured to support the tail rotor gearbox within the shroud. The tail rotor gearbox support assembly includes a support column coupling the aft side of the tail rotor gearbox between the top and bottom portions of the shroud airframe, an upper support crossbar coupling the top side of the tail rotor gearbox between the support column and the tailboom airframe and a lower support crossbar coupling the bottom side of the tail rotor gearbox between the support column and the tailboom airframe.

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 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 propulsion and lift system for an aircraft includes a wing having an outboard end and a pylon assembly coupled to the outboard end of the wing. The propulsion and lift system also includes a wing extension rotatably coupled to the outboard end of the pylon assembly. The wing extension is rotatable between a flight position in a flight mode and a stow position in a storage mode. The wing extension folds inboard in the stow position, thereby reducing a wingspan of the aircraft in the storage mode.

Abstract: An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled to the engine and a lateral movement control assembly coupled between the torsion bar and the airframe. The lateral movement control assembly includes a spring having a lateral stiffness. The torsion bar rotates in response to lateral movement of the engine such that the lateral movement of the engine is controllable based on the lateral stiffness of the spring.

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 rotorcraft, such as a tiltrotor aircraft having helicopter and airplane modes, includes an airframe, an engine and an engine mount assembly for coupling the engine to the airframe. The engine includes an engine lug forming an aperture. The engine mount assembly includes a mount having an aperture substantially aligned with the engine lug aperture. A sleeved bolt assembly extends through the apertures to secure the engine lug to the mount. The sleeved bolt assembly includes a bolt undersized relative to the apertures forming a circumferential gap within the apertures, a sleeve disposed around at least a portion of the bolt substantially filling the circumferential gap and a nut adapted to thread onto a threaded portion of the bolt. The use of the undersized bolt within the sleeve permits increased clearance between the sleeved bolt assembly and the engine while maintaining strength requirements in high load environments.

Abstract: An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled to the engine and a lateral movement control assembly coupled between the torsion bar and the airframe. The lateral movement control assembly includes a spring having a lateral stiffness. The torsion bar rotates in response to lateral movement of the engine such that the lateral movement of the engine is controllable based on the lateral stiffness of the spring.

Abstract: A rotorcraft, such as a tiltrotor aircraft having helicopter and airplane modes, includes an airframe, an engine and an engine mount assembly for coupling the engine to the airframe. The engine includes an engine lug forming an aperture. The engine mount assembly includes a mount having an aperture substantially aligned with the engine lug aperture. A sleeved bolt assembly extends through the apertures to secure the engine lug to the mount. The sleeved bolt assembly includes a bolt undersized relative to the apertures forming a circumferential gap within the apertures, a sleeve disposed around at least a portion of the bolt substantially filling the circumferential gap and a nut adapted to thread onto a threaded portion of the bolt. The use of the undersized bolt within the sleeve permits increased clearance between the sleeved bolt assembly and the engine while maintaining strength requirements in high load environments.