Disclosed are systems and methods for maintaining bulk fuel temperatures in an aircraft. In one aspect, a recirculation system causes fuel to be delivered from a relatively low point near the feed hopper of each tank on the aircraft to one or more outboard locations of the wings. Once there, the fuel, due to gravity, flows back over the lower skin of the wing in channels back towards the fuselage, thus cooling the fuel. In other aspects, control systems are disclosed that coordinate the recirculation based on fuel levels in the tanks and fuel temperatures. The control systems also utilize a fuel scavenge system to maintain acceptable temperatures in the tanks.

Disclosed are systems and methods for maintaining bulk fuel temperatures in an aircraft. In one aspect, a recirculation system causes fuel to be delivered from a relatively low point near the feed hopper of each tank on the aircraft to one or more outboard locations of the wings. Once there, the fuel, due to gravity, flows back over the lower skin of the wing in channels back towards the fuselage, thus cooling the fuel. In other aspects, control systems are disclosed that coordinate the recirculation based on fuel levels in the tanks and fuel temperatures. The control systems also utilize a fuel scavenge system to maintain acceptable temperatures in the tanks.

An exemplary cushion for a fuel system is constructed of a lattice structure formed of a material that is substantially nonabsorbent of fuel and has a network of nodes and beams defining cells, an exterior surface of the lattice structure is configured to be oriented toward a fuel cell and an interior surface of the lattice structure is configured to fit to a mounting surface.

An exemplary cushion for a fuel system is constructed of a lattice structure formed of a material that is substantially nonabsorbent of fuel and has a network of nodes and beams defining cells, an exterior surface of the lattice structure is configured to be oriented toward a fuel cell and an interior surface of the lattice structure is configured to fit to a mounting surface.

An aircraft including a fuselage, a power generator configured to provide power to the aircraft, and at least one fuel tank for holding fuel for the power generator, and a fuel delivery assembly. The fuel tank is positioned in the fuselage and is configured to hold hydrogen fuel in a liquid phase. The fuel tank has a chamber for holding the hydrogen fuel and a fuel extraction line fluidly coupled to the chamber. The fuel extraction line extends from the fuel tank in a forward direction of the fuselage and at a downward angle relative to a centerline of the fuselage. The fuel delivery assembly is fluidly coupled to the fuel extraction line and fluidly connects the fuel tank to the power generator. The fuel delivery assembly is configured to provide the hydrogen fuel from the fuel tank to the power generator.

An aircraft including a fuselage, a power generator configured to provide power to the aircraft, and at least one fuel tank for holding fuel for the power generator, and a fuel delivery assembly. The fuel tank is positioned in the fuselage and is configured to hold hydrogen fuel in a liquid phase. The fuel tank has a chamber for holding the hydrogen fuel and a fuel extraction line fluidly coupled to the chamber. The fuel extraction line extends from the fuel tank in a forward direction of the fuselage and at a downward angle relative to a centerline of the fuselage. The fuel delivery assembly is fluidly coupled to the fuel extraction line and fluidly connects the fuel tank to the power generator. The fuel delivery assembly is configured to provide the hydrogen fuel from the fuel tank to the power generator.

A cooling system includes a thermal engine having a fluid output, and a motor drive having a fluid inlet in fluid communication with the fluid output of the thermal engine. The fluid inlet of the motor drive is downstream from the fluid output of the thermal engine. The system includes a fluid storage downstream from the motor drive and a fluid output of the motor drive. A method of cooling a motor drive includes outputting a cooling fluid from a fluid output of a thermal engine, receiving the cooling fluid from the fluid output of the thermal engine in a fluid inlet of a motor drive, passing the cooling fluid through the motor drive to a fluid output of the motor drive, receiving the cooling fluid in a fluid storage.

A cooling system includes a thermal engine having a fluid output, and a motor drive having a fluid inlet in fluid communication with the fluid output of the thermal engine. The fluid inlet of the motor drive is downstream from the fluid output of the thermal engine. The system includes a fluid storage downstream from the motor drive and a fluid output of the motor drive. A method of cooling a motor drive includes outputting a cooling fluid from a fluid output of a thermal engine, receiving the cooling fluid from the fluid output of the thermal engine in a fluid inlet of a motor drive, passing the cooling fluid through the motor drive to a fluid output of the motor drive, receiving the cooling fluid in a fluid storage.

A cryogenic tank for storing cryogenic fluids is disclosed. The cryogenic tank is typically configured to be mounted on a vehicle for supplying cryogenic fuel to a propulsion system of the vehicle. The cryogenic tank comprises an inner vessel for containing cryogenic fluids and an outer vessel surrounding the inner vessel to define a vacuum insulating volume therebetween. The outer vessel is configured to transmit static and/or dynamic loads, while the inner vessel is partially or completely isolated from such loads.

A cryogenic tank for storing cryogenic fluids is disclosed. The cryogenic tank is typically configured to be mounted on a vehicle for supplying cryogenic fuel to a propulsion system of the vehicle. The cryogenic tank comprises an inner vessel for containing cryogenic fluids and an outer vessel surrounding the inner vessel to define a vacuum insulating volume therebetween. The outer vessel is configured to transmit static and/or dynamic loads, while the inner vessel is partially or completely isolated from such loads.