Abstract: Systems and methods for pivoting main landing gear of a cargo aircraft. One embodiment is a main landing gear of an aircraft that includes a shock strut coupled to a truck with one or more wheels, and a trunnion coupled to a bulkhead and configured to pivotally couple the shock strut with the bulkhead. The main landing gear also includes a folding brace extending from the shock strut in a forward direction toward a nose of the aircraft and configured to stabilize the shock strut. The main landing gear further includes a retraction actuator configured to pivot the shock strut about the trunnion to retract the one or more wheels in the forward direction toward the nose and up toward a fuselage of the aircraft.

Abstract: Systems and methods for bipedal nose landing gear of an aircraft. One embodiment is a nose landing gear of an aircraft. The nose landing gear includes a shock strut coupled to an axle with a nose wheel, and a folding side brace extending from the shock strut inboard toward a belly of the aircraft and configured to stabilize the shock strut. The nose landing gear also includes a trunnion configured to pivot the shock strut forward toward a nose and inboard toward the belly of the aircraft to retract the nose wheel.

Abstract: Systems and methods for wide set retracting landing gear of a cargo aircraft. One embodiment is an aircraft that includes a fuselage including a nose, and a pair of main landing gears comprising a pair of main posts disposed across the fuselage, each main post having a main wheel and configured to pivot forward toward the nose to retract the main wheel. The aircraft also includes a pair of nose landing gears comprising a pair of nose posts disposed across the fuselage, each nose post having a nose wheel and configured to pivot inboard to retract the nose wheel.

Abstract: Systems and methods for folding landing gear of a cargo aircraft. One embodiment is a main landing gear of an aircraft that includes a shock strut coupled to a truck with one or more wheels, and a yoke pivotally coupled with the shock strut via a lower trunnion, and pivotally coupled with an aircraft structure via an upper trunnion. The yoke is configured to pivot about the upper trunnion in a direction back toward a tail of the aircraft and up toward a fuselage of the aircraft, and the shock strut is configured to pivot about the lower trunnion in a direction forward toward a nose of the aircraft and up toward the fuselage of the aircraft to retract the one or more wheels.

Abstract: Methods of retracting a strut assembly for stowing aircraft landing gear comprise longitudinally translating an upper bulkhead within an upper tubular housing from a lower position to an upper position by pressurizing an upper bulkhead space between an upper plate of the upper bulkhead and an upper bulkhead restriction structure that is fixed to the upper tubular housing. Other methods of retracting a strut assembly for stowing aircraft landing gear comprise flowing liquid from an upper liquid chamber positioned above an upper bulkhead within an upper tubular housing to a recoil chamber, wherein during the flowing, the liquid is prevented from passing from the recoil chamber to a pressure chamber that is defined between the upper bulkhead and a lower bulkhead, thereby longitudinally translating a lower tubular housing upward.

Abstract: Systems and methods for bipedal nose landing gear of an aircraft. One embodiment is a nose landing gear of an aircraft. The nose landing gear includes a shock strut coupled to an axle with a nose wheel, and a folding side brace extending from the shock strut inboard toward a belly of the aircraft and configured to stabilize the shock strut. The nose landing gear also includes a trunnion configured to pivot the shock strut forward toward a nose and inboard toward the belly of the aircraft to retract the nose wheel.

Abstract: Systems and methods for wide set retracting landing gear of a cargo aircraft. One embodiment is an aircraft that includes a fuselage including a nose, and a pair of main landing gears comprising a pair of main posts disposed across the fuselage, each main post having a main wheel and configured to pivot forward toward the nose to retract the main wheel. The aircraft also includes a pair of nose landing gears comprising a pair of nose posts disposed across the fuselage, each nose post having a nose wheel and configured to pivot inboard to retract the nose wheel.

Abstract: Systems and methods for folding landing gear of a cargo aircraft. One embodiment is a main landing gear of an aircraft that includes a shock strut coupled to a truck with one or more wheels, and a yoke pivotally coupled with the shock strut via a lower trunnion, and pivotally coupled with an aircraft structure via an upper trunnion. The yoke is configured to pivot about the upper trunnion in a direction back toward a tail of the aircraft and up toward a fuselage of the aircraft, and the shock strut is configured to pivot about the lower trunnion in a direction forward toward a nose of the aircraft and up toward the fuselage of the aircraft to retract the one or more wheels.

Abstract: Systems and methods for pivoting main landing gear of a cargo aircraft. One embodiment is a main landing gear of an aircraft that includes a shock strut coupled to a truck with one or more wheels, and a trunnion coupled to a bulkhead and configured to pivotally couple the shock strut with the bulkhead. The main landing gear also includes a folding brace extending from the shock strut in a forward direction toward a nose of the aircraft and configured to stabilize the shock strut. The main landing gear further includes a retraction actuator configured to pivot the shock strut about the trunnion to retract the one or more wheels in the forward direction toward the nose and up toward a fuselage of the aircraft.

Abstract: Methods of retracting a strut assembly for stowing aircraft landing gear comprise longitudinally translating an upper bulkhead within an upper tubular housing from a lower position to an upper position by pressurizing an upper bulkhead space between an upper plate of the upper bulkhead and an upper bulkhead restriction structure that is fixed to the upper tubular housing. Other methods of retracting a strut assembly for stowing aircraft landing gear comprise flowing liquid from an upper liquid chamber positioned above an upper bulkhead within an upper tubular housing to a recoil chamber, wherein during the flowing, the liquid is prevented from passing from the recoil chamber to a pressure chamber that is defined between the upper bulkhead and a lower bulkhead, thereby longitudinally translating a lower tubular housing upward.

Abstract: An aircraft landing gear structure includes a strut assembly configured to transition between a compressed configuration, an extended configuration, and a retracted configuration. The strut assembly has a compressed length, an extended length, and a retracted length, such that the compressed length and retracted length are less than the extended length. The strut assembly includes an upper tubular housing, an upper bulkhead configured to be translated between a lower position and an upper position, a lower tubular housing operatively coupled to the upper tubular housing, a lower bulkhead supported by the lower tubular housing, and a pressure chamber defined between the lower bulkhead and the upper bulkhead. A volume of strut liquid and a mass of strut gas are positioned within the pressure chamber. A method of retracting a strut assembly includes longitudinally translating an upper bulkhead within an upper tubular housing from a lower position to an upper position.

Abstract: An aircraft landing gear structure includes a strut assembly configured to transition between a compressed configuration, an extended configuration, and a retracted configuration. The strut assembly has a compressed length, an extended length, and a retracted length, such that the compressed length and retracted length are less than the extended length. The strut assembly includes an upper tubular housing, an upper bulkhead configured to be translated between a lower position and an upper position, a lower tubular housing operatively coupled to the upper tubular housing, a lower bulkhead supported by the lower tubular housing, and a pressure chamber defined between the lower bulkhead and the upper bulkhead. A volume of strut liquid and a mass of strut gas are positioned within the pressure chamber. A method of retracting a strut assembly includes longitudinally translating an upper bulkhead within an upper tubular housing from a lower position to an upper position.

Abstract: A method and apparatus for positioning a tail skid assembly for a maximum rotation angle for an aircraft may be provided. A determination may be made as to whether the tail skid assembly is to be deployed for takeoff or landing. A set of parameters may be identified based on a determination of whether the tail skid assembly is to be deployed for takeoff or landing. A desired maximum rotation angle for the aircraft may be identified using the set of parameters. The tail skid assembly may be deployed to allow the desired maximum rotation angle for the aircraft.

Abstract: A method and apparatus for positioning a tail skid assembly for a maximum rotation angle for an aircraft may be provided. A determination may be made as to whether the tail skid assembly is to be deployed for takeoff or landing. A set of parameters may be identified based on a determination of whether the tail skid assembly is to be deployed for takeoff or landing. A desired maximum rotation angle for the aircraft may be identified using the set of parameters. The tail skid assembly may be deployed to allow the desired maximum rotation angle for the aircraft.

Abstract: A method and apparatus for changing a length of a landing gear system. A first cylinder and a second cylinder are moved relative to each other along an axis extending centrally through the first cylinder and the second cylinder such that the first cylinder and the second cylinder are in an extended position. In response to the first cylinder and the second cylinder being in the extended position, a flow of a fluid is substantially prevented between a first chamber formed between the first cylinder and the second cylinder and a second chamber within the first cylinder and the second cylinder. In response to a pressure applied to the first chamber, the first cylinder and the second cylinder are moved relative to each other along the axis such that a length of the first cylinder and the second cylinder is reduced.

Abstract: A method and apparatus for positioning a tail skid assembly for a maximum rotation angle for an aircraft may be provided. A determination may be made as to whether the tail skid assembly is to be deployed for takeoff or landing. A set of parameters may be identified based on a determination of whether the tail skid assembly is to be deployed for takeoff or landing. A desired maximum rotation angle for the aircraft may be identified using the set of parameters. The tail skid assembly may be deployed to allow the desired maximum rotation angle for the aircraft.

Abstract: A method and apparatus for controlling noise. An apparatus may comprise a structure configured to be positioned at an opening for a channel. The channel may be formed at least partially within a fastener. The structure may be configured to change a movement of air within the channel to reduce noise generated by the movement of air within the channel.

Abstract: A method and apparatus for positioning a tail skid assembly for a maximum rotation angle for an aircraft may be provided. A determination may be made as to whether the tail skid assembly is to be deployed for takeoff or landing. A set of parameters may be identified based on a determination of whether the tail skid assembly is to be deployed for takeoff or landing. A desired maximum rotation angle for the aircraft may be identified using the set of parameters. The tail skid assembly may be deployed to allow the desired maximum rotation angle for the aircraft.

Abstract: A method and apparatus for changing a length of a landing gear system. A first cylinder and a second cylinder are moved relative to each other along an axis extending centrally through the first cylinder and the second cylinder such that the first cylinder and the second cylinder are in an extended position. In response to the first cylinder and the second cylinder being in the extended position, a flow of a fluid is substantially prevented between a first chamber formed between the first cylinder and the second cylinder and a second chamber within the first cylinder and the second cylinder. In response to a pressure applied to the first chamber, the first cylinder and the second cylinder are moved relative to each other along the axis such that a length of the first cylinder and the second cylinder is reduced.