A hydrogen boiloff capture system. The hydrogen boiloff capture system having a cryogenic tank for storing liquid hydrogen. The hydrogen boiloff capture system also includes an intermediate tank fluidically coupled with the cryogenic tank. The intermediate tank is configured to receive hydrogen gas boiloff from the cryogenic tank. The intermediate tank is further configured to provide the hydrogen gas boiloff to a lighter-than-air craft to regulate buoyancy of the lighter-than-air craft. The intermediate tank is also configured to provide the hydrogen gas boiloff to a hydrogen fuel cell coupled to the lighter-than-air craft.

A hydrogen boiloff capture system. The hydrogen boiloff capture system having a cryogenic tank for storing liquid hydrogen. The hydrogen boiloff capture system also includes an intermediate tank fluidically coupled with the cryogenic tank. The intermediate tank is configured to receive hydrogen gas boiloff from the cryogenic tank. The intermediate tank is further configured to provide the hydrogen gas boiloff to a lighter-than-air craft to regulate buoyancy of the lighter-than-air craft. The intermediate tank is also configured to provide the hydrogen gas boiloff to a hydrogen fuel cell coupled to the lighter-than-air craft.

Fuel tank inerting systems for aircraft are described. The systems include a fuel tank, a first reactant source fluidly connected to the fuel tank, a second reactant source, a catalytic reactor arranged to receive a first reactant from the first source and a second reactant from the second source to generate an inert gas that is supplied to the fuel tank to fill a ullage space of the fuel tank, a heat exchanger arranged between the catalytic reactor and the fuel tank and configured to at least one of cool and condense an output from the catalytic reactor to separate out an inert gas and a byproduct, a reheater arranged between the catalytic reactor and the heat exchanger, and a recirculation loop configured to extract air from downstream of the heat exchanger, pass the extracted air through the reheater, and inject reheated air upstream of the catalytic reactor.

Method and system for managing hydrogen fuel in hydrogen fuel cell-powered aircraft is disclosed. The method identifies unused hydrogen fuel in a fuel tank of the aircraft. Determines an amount of the unused hydrogen fuel in the fuel tank of the aircraft. Transfers the amount of the unused hydrogen fuel from the fuel tank of the aircraft into a hydrogen fuel cell of the aircraft and converts the amount of the unused hydrogen fuel into electricity via the hydrogen fuel cell of the aircraft.

Method and system for managing hydrogen fuel in hydrogen fuel cell-powered aircraft is disclosed. The method identifies unused hydrogen fuel in a fuel tank of the aircraft. Determines an amount of the unused hydrogen fuel in the fuel tank of the aircraft. Transfers the amount of the unused hydrogen fuel from the fuel tank of the aircraft into a hydrogen fuel cell of the aircraft and converts the amount of the unused hydrogen fuel into electricity via the hydrogen fuel cell of the aircraft.

An aircraft having a fuselage having a pressurized upper space above the floor and a lower space beneath the floor, a wing, a hollow support stay fixed between the lower space level of the fuselage and the wing, an electric motor propeller propulsion system fixed beneath each wing, the output shaft of the motor driving a propeller in rotation, a production system having a fuel cell producing electrical energy supplying the electric motor with electricity via electrical conductors, a hydrogen reservoir fixed in the lower space, and a hydrogen inlet pipe feeding hydrogen from a hydrogen reservoir to the production system, wherein the hydrogen inlet pipe extends through the interior of the support stay. The electrical conductors or the hydrogen pipes pass through the stays on the outside of the fuselage and therefore at a distance from the passengers and the electronic systems of the aircraft.

A method includes receiving wavelength domain data for a time step, performing a Discrete Fourier Transform (DFT) to transform the wavelength domain data for the time step into frequency domain data for the time step only for the limited set of frequency bins associated with a frequency of interest, calculating pressure based on the frequency domain data for the time step, and updating the frequency of interest and the limited set of frequency bins. The method includes repeating receiving wavelength data for subsequent time steps, performing a DFT to transform the wavelength data for the respective subsequent time steps, calculating pressure for each subsequent time step, and updating the frequency of interest and limited set of frequency bins for each subsequent time step. The method includes outputting pressure data based on calculating pressure for the subsequent time steps.

A method includes receiving wavelength domain data for a time step, performing a Discrete Fourier Transform (DFT) to transform the wavelength domain data for the time step into frequency domain data for the time step only for the limited set of frequency bins associated with a frequency of interest, calculating pressure based on the frequency domain data for the time step, and updating the frequency of interest and the limited set of frequency bins. The method includes repeating receiving wavelength data for subsequent time steps, performing a DFT to transform the wavelength data for the respective subsequent time steps, calculating pressure for each subsequent time step, and updating the frequency of interest and limited set of frequency bins for each subsequent time step. The method includes outputting pressure data based on calculating pressure for the subsequent time steps.

A fuel freeze mitigation and/or prevention system includes a power generator configured and adapted to be positioned within a fuel storage tank. A fluid mover device is in electrical communication with the power generator. The fluid mover device is configured and adapted to be positioned within a fuel storage tank to mitigate or prevent fuel freeze in the fuel storage tank. A method for mitigating or preventing fuel freeze in a fuel storage tank includes harvesting energy with a power generator positioned within the fuel storage tank, charging a battery with the harvested energy, monitoring a fuel temperature inside the fuel storage tank, and turning a fluid mover device positioned within the fuel storage tank ON or OFF depending on at least one of a manual command or the fuel temperature inside the fuel storage tank to mitigate or prevent fuel freeze in the fuel storage tank.

A fuel freeze mitigation and/or prevention system includes a power generator configured and adapted to be positioned within a fuel storage tank. A fluid mover device is in electrical communication with the power generator. The fluid mover device is configured and adapted to be positioned within a fuel storage tank to mitigate or prevent fuel freeze in the fuel storage tank. A method for mitigating or preventing fuel freeze in a fuel storage tank includes harvesting energy with a power generator positioned within the fuel storage tank, charging a battery with the harvested energy, monitoring a fuel temperature inside the fuel storage tank, and turning a fluid mover device positioned within the fuel storage tank ON or OFF depending on at least one of a manual command or the fuel temperature inside the fuel storage tank to mitigate or prevent fuel freeze in the fuel storage tank.