Some embodiments are directed to an apparatus, such as a panel that might be appropriate for aircraft or space vehicle fuel tanks. According to some embodiments, a plurality of stiffening elements may be attached to a matrix stiffened laminate skin and arranged in an isogrid pattern. Each stiffening element may include, for example, a hollow hat-shaped and substantially rectangular cross-sectional profile and a layer of unidirectional fibers proximate to a top portion of the stiffening element. In some embodiments, the stiffening elements may be created on top of a core element that is later removed (e.g., by dissolving, melting, or vaporizing the core element after the stiffening elements and fiber skin are cured with heat).

Some embodiments are directed to an apparatus, such as a panel that might be appropriate for aircraft or space vehicle fuel tanks. According to some embodiments, a plurality of stiffening elements may be attached to a matrix stiffened laminate skin and arranged in an isogrid pattern. Each stiffening element may include, for example, a hollow hat-shaped and substantially rectangular cross-sectional profile and a layer of unidirectional fibers proximate to a top portion of the stiffening element. In some embodiments, the stiffening elements may be created on top of a core element that is later removed (e.g., by dissolving, melting, or vaporizing the core element after the stiffening elements and fiber skin are cured with heat).

Various non-limiting embodiments of a tool for actuating a valve, a method for making a tool for actuating a valve, and a method for actuating a valve, are provided. In one example, the tool includes a shaft defining a longitudinal axis and configured to transfer force to the valve for actuating the valve. A body has a wall surrounding a portion of the shaft. The wall defines a track that is formed therein and that has a track section substantially parallel to the longitudinal axis. A positive feature is coupled to the shaft and disposed in the track. The shaft is slidingly coupled to the body and when a force is applied to the shaft in a direction aligned with the longitudinal axis, the shaft moves relative to the body and the positive feature moves through the track section that restricts the shaft from being rotated about the longitudinal axis.

An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.

An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.

A vent wash cover for covering an aircraft vent with a plurality of slots. The vent wash cover includes a main body, fingers, a threaded aperture, and a hollow conic section. The main body has a first end and a second end. The fingers are disposed on the first end and correspond in size and placement to the plurality of slots such that a seal is created between the fingers and plurality of slots. The threaded aperture is disposed on the second end, and corresponds to threads of a standard thread extension pole. The hollow conic section extends outward from the threaded aperture such that the threads of the standard thread extension pole can be properly aligned from a distance for insertion into the threaded aperture.

Methods and systems for venting a fuel tank includes a fuel tank on a blended wing body aircraft. A fuel tank may include a vent. A vent line is connected to the vent. The vent line is heated. The vent line is attached to an external fuel tank configured to store the collected boil-off gaseous fuel from the aircraft fuel tank.

Methods and systems for venting a fuel tank includes a fuel tank on a blended wing body aircraft. A fuel tank may include a vent. A vent line is connected to the vent. The vent line is heated. The vent line is attached to an external fuel tank configured to store the collected boil-off gaseous fuel from the aircraft fuel tank.

A reservoir includes first and second chambers, and a piston having first and second ends disposed in the first and second chambers, respectively. The first and second ends isolate a first area from a second area within the first and second chambers. The first area of the first chamber is in fluid communication with a high pressure fluid source and the second area of the first chamber is in fluid communication with a low pressure fluid source. An orifice is formed in the first end and is configured to allow fluid communication between the upper and lower areas of the first chamber. A pumping system and an aircraft are also disclosed.

A reservoir includes first and second chambers, and a piston having first and second ends disposed in the first and second chambers, respectively. The first and second ends isolate a first area from a second area within the first and second chambers. The first area of the first chamber is in fluid communication with a high pressure fluid source and the second area of the first chamber is in fluid communication with a low pressure fluid source. An orifice is formed in the first end and is configured to allow fluid communication between the upper and lower areas of the first chamber. A pumping system and an aircraft are also disclosed.