An aircraft with a multi-walled fuel tank and method of manufacturing is presented. The aircraft includes a blended wing body and a fuel tank attached to the blended wing body configured to store liquified gas fuel. The fuel tank includes an inner wall, outer wall, and interstitial volume in between that is filled with insulation. The interstitial volume includes a reflective film layer and a structural insulation layer.

A safety management system for an aircraft, or a propulsion system thereof including a fuel cell assembly and a combustion engine, may include various sensors and controllers configured to execute a safety action. At least one sensor is configured to detect at least one operating parameter of the propulsion system, and a controller is configured to determine that the at least one operating parameter has achieved a safety threshold and to execute a safety action when the at least one operating parameter has achieved the safety threshold. The safety action is configured to control operation of the fuel cell assembly and to control operation of the combustion engine.

A propulsion system comprising a nacelle with an air channel along a longitudinal direction, an electric motor whose output drives a propeller, and a fuel cell, comprising a core outside the air channel, open channels, each of which has an inlet and an outlet opening in the air channel, and, for each open channel, a fuel chamber, an electrolyte between the open channel and the fuel chamber, a cathode, and an anode, each open channel having an inlet surface area which is less than the surface area of an intermediate area between the inlet and the outlet, the surface area of the outlet being smaller than the surface area of the intermediate area. Such a system makes it possible to have the fuel cell close to the electric motor, thereby reducing the lengths of the electrical conductors between them, and consequently improving the operation of the fuel cell.

A propulsion system comprising a nacelle with an air channel along a longitudinal direction, an electric motor whose output drives a propeller, and a fuel cell, comprising a core outside the air channel, open channels, each of which has an inlet and an outlet opening in the air channel, and, for each open channel, a fuel chamber, an electrolyte between the open channel and the fuel chamber, a cathode, and an anode, each open channel having an inlet surface area which is less than the surface area of an intermediate area between the inlet and the outlet, the surface area of the outlet being smaller than the surface area of the intermediate area. Such a system makes it possible to have the fuel cell close to the electric motor, thereby reducing the lengths of the electrical conductors between them, and consequently improving the operation of the fuel cell.

In order to improve liquid hydrogen storage on aircraft, a liquid hydrogen tank is integrated into the fuselage of the aircraft. At least one portion of the tank wall is formed by specially adapted tank skin panels and/or a pressure bulkhead. The parts forming the tank wall are strengthened to contain a tank pressure of about 3 bar.

A power distribution controller for a hybrid aircraft is configured to continuously: obtain a state-of-charge (SoC) measurement for a battery of the hybrid aircraft; obtain a fuel level measurement for a secondary energy source of the hybrid aircraft; receive a control input indicating one of a throttle level or an operating mode for one or more motors of the hybrid aircraft; calculate a ratio of energy to source from each of the battery and the secondary energy source in order to operate the one or more motors of the hybrid aircraft based on the control input, the SoC measurement, and the fuel level measurement; and transmit a control signal that causes energy to be apportioned from the battery and the secondary energy source to the one or more motors based on the determined ratio.

In accordance with at least one aspect of this disclosure, a fluid system of an aircraft includes a primary fluid conduit that conveys a primary fluid, and a leak detection system disposed around at least a portion of the primary fluid conduit and forming one or more detection volumes. The leak detection system determines whether there is a primary fluid leak into the one or more detection volumes by sensing a pressure change in the one or more detection volumes.

In accordance with at least one aspect of this disclosure, a fluid system of an aircraft includes a primary fluid conduit that conveys a primary fluid, and a leak detection system disposed around at least a portion of the primary fluid conduit and forming one or more detection volumes. The leak detection system determines whether there is a primary fluid leak into the one or more detection volumes by sensing a pressure change in the one or more detection volumes.

A propulsion system is provided and includes a solid hydride storage unit from which gaseous hydrogen fuel is drawn, an engine comprising a combustion chamber and a piping system to draw the gaseous hydrogen fuel from the solid hydride storage unit, the piping system being interposed between the solid hydride storage unit and the combustion chamber. The combustion chamber is receptive of the gaseous hydrogen fuel drawn from the solid hydride storage unit by the piping system and is configured to combust the gaseous hydrogen fuel to drive an operation of the engine.

A propulsion system is provided and includes a solid hydride storage unit from which gaseous hydrogen fuel is drawn, an engine comprising a combustion chamber and a piping system to draw the gaseous hydrogen fuel from the solid hydride storage unit, the piping system being interposed between the solid hydride storage unit and the combustion chamber. The combustion chamber is receptive of the gaseous hydrogen fuel drawn from the solid hydride storage unit by the piping system and is configured to combust the gaseous hydrogen fuel to drive an operation of the engine.