Abstract: A hydrogen-fuelled aircraft power system incorporates a gas turbine engine and a fuel cell, in which air supply and cooling of the fuel cell is integrated with the gas turbine engine to improve overall efficiency of the power system. The system may be part of a turbofan, turboprop or electric propulsion system for an aircraft.

Abstract: A hydrogen-fuelled gas turbine engine has a fuel input path from a fuel input of the engine to a combustor, the engine further comprising a heat-exchanger located in the fuel input path and a fuel turbine located in the fuel input path between the heat-exchanger and the combustor. The heat-exchanger is arranged to receive waste heat from the engine core in order to heat hydrogen fuel introduced at the fuel input prior to input thereof to the combustor. The engine further comprises an air compressor arranged to be driven by the fuel turbine. The engine provides for most of the waste heat of combustion to be recovered and used without the need for heavy electrical or mechanical apparatus and is therefore particularly advantageous in aeronautical applications.

Abstract: An aircraft propulsion system (10) comprises at least first and second electrical generators (15a, 15b), each being configured to provide electrical power to a respective first and second AC electrical network (16a, 16b). The system (10) further comprises at least first and second AC electrical motors (19a, 19b) directly electrically coupled to a respective AC network (16a, 16b) and coupled to a respective propulsor (4), and a DC electrical network electrically coupled to the first and second AC networks (16a, 16b) via respective first and second AC to DC converters (17a, 17b), and to a further electrical motor 19c), the further electrical motor (19c) being coupled to a propulsor (4).

Abstract: An axial flux electrical machine comprises a first flux generating assembly, a second flux generating assembly, a shaft and a speed controller. The shaft has an axis of rotation. Each of the first flux generating assembly and the second flux generating assembly is rotationally located on the shaft in axial juxtaposition to one another, with the first flux generating assembly being axially separated from the second flux generating assembly by a separation distance. The speed controller is configured to modify a magnetic field generated by either of the first flux generating assembly and the second flux generating assembly so as to control a rotational speed of the electrical machine.