A fuel system is provided for an aircraft having a fuel source. The fuel system includes a fuel oxygen reduction unit defining a liquid fuel supply path, a stripping gas supply path, a liquid fuel outlet path, and a stripping gas return path, wherein the stripping gas return path is in airflow communication with the fuel source.

A cryogenic fuel tank for retrofitting a conventional fossil-fuel-powered aircraft, or for a purposely built aircraft to run on hydrogen has an aerodynamically shaped outer surface including an ogive shaped nose cone, and a tapered tail cone, wherein the tapered tail cone includes actively adjustable elements for adjusting aerodynamic characteristics of the cryogenic fuel tank. The cryogenic fuel tank is configured to be attached below wings of the aircraft, through support pylons, which include sensors configured to measure forces applied by the cryogenic fuel tank to the airframe. The cryogenic fuel tank includes a nozzle and valve configured to vent gas from the cryogenic fuel tank by expansion through the nozzle in the event that the cryogenic fuel tank is jettisoned from the aircraft.

A cryogenic fuel tank for retrofitting a conventional fossil-fuel-powered aircraft, or for a purposely built aircraft to run on hydrogen has an aerodynamically shaped outer surface including an ogive shaped nose cone, and a tapered tail cone, wherein the tapered tail cone includes actively adjustable elements for adjusting aerodynamic characteristics of the cryogenic fuel tank. The cryogenic fuel tank is configured to be attached below wings of the aircraft, through support pylons, which include sensors configured to measure forces applied by the cryogenic fuel tank to the airframe. The cryogenic fuel tank includes a nozzle and valve configured to vent gas from the cryogenic fuel tank by expansion through the nozzle in the event that the cryogenic fuel tank is jettisoned from the aircraft.

A fuel system for a composite aircraft is described which includes an ejector pump having a vacuum inlet in communication with a fuel storage tank, an engine feed pump having an inlet in fluid communication with an outlet of the ejector pump, a primary outlet in communication with an engine, and a motive flow outlet, upstream of an oil-fuel heat exchanger, that is in fluid communication with an inlet of the ejector pump. A motive flow pump assembly is disposed between the motive flow outlet of the engine feed pump and the inlet of the ejector pump. The motive flow pump assembly includes an inlet screen and a motive flow pump, the inlet screen having a plurality of openings therein and a hydrophobic upstream surface. The openings are dimensioned to prevent passage of particles greater than a selected threshold size while allowing liquids to flow therethrough.

A fuel system for a composite aircraft is described which includes an ejector pump having a vacuum inlet in communication with a fuel storage tank, an engine feed pump having an inlet in fluid communication with an outlet of the ejector pump, a primary outlet in communication with an engine, and a motive flow outlet, upstream of an oil-fuel heat exchanger, that is in fluid communication with an inlet of the ejector pump. A motive flow pump assembly is disposed between the motive flow outlet of the engine feed pump and the inlet of the ejector pump. The motive flow pump assembly includes an inlet screen and a motive flow pump, the inlet screen having a plurality of openings therein and a hydrophobic upstream surface. The openings are dimensioned to prevent passage of particles greater than a selected threshold size while allowing liquids to flow therethrough.

A dual lock flow gate includes a valve with a flapper which may be fixed and/or locked in various positions.

A dual lock flow gate includes a valve with a flapper which may be fixed and/or locked in various positions.

An expandable liquid tank device is secured to a vehicle to provided externally pressurized fuel to the fuel system of the vehicle. The tank can comprise an outer bladder containing a flexible inner bladder. An end plate can secure the bladders to the vehicle. Upon depositing fuel into the flexible inner bladder, the outer bladder expands and conforms to a tank region of the vehicle. The outer bladder (a pliable material) transitions from a flexible state to a semi-rigid or substantially rigid state upon depositing fuel into the flexible inner bladder. To provide pressurized fuel to the vehicle, pressurized gas is injected between the bladders, which exert pressure against the flexible inner bladder to dispense the fuel through the end plate and to the fuel system. A method of making the tank and dispensing fuel is provided.

An expandable liquid tank device is secured to a vehicle to provided externally pressurized fuel to the fuel system of the vehicle. The tank can comprise an outer bladder containing a flexible inner bladder. An end plate can secure the bladders to the vehicle. Upon depositing fuel into the flexible inner bladder, the outer bladder expands and conforms to a tank region of the vehicle. The outer bladder (a pliable material) transitions from a flexible state to a semi-rigid or substantially rigid state upon depositing fuel into the flexible inner bladder. To provide pressurized fuel to the vehicle, pressurized gas is injected between the bladders, which exert pressure against the flexible inner bladder to dispense the fuel through the end plate and to the fuel system. A method of making the tank and dispensing fuel is provided.

A hydrogen tank assembly is provided for use in vehicles, such as aircraft. The hydrogen tank assembly has an inner tank wall, an outer tank wall, and an inert gas source. The inner tank wall defines a hydrogen tank volume that is surrounded by a shroud volume which is defined by the outer tank wall. The hydrogen tank volume is filled with cryogenic hydrogen and has a higher pressure than the shroud volume that is filled with an inert gas, such as helium. The counter-pressure of the inert gas prevents micro-cracks in the inner tank wall and increases the in-service life.