Abstract: A superconducting electrical power distribution network has a superconducting bus bar and superconducting cables electrically connected to the bus bar at respective joints distributed along the bus bar. The network further has a first coolant system for providing first cryogenic fluid and first circuits for circulating the first cryogenic fluid provided by the first coolant system. The first circuits comprise: a bus bar flow path which extends along and thereby cools the bus bar, cable flow paths which respectively extend along and thereby cool the cables, cooling junctions where the bus bar and cable flow paths meet at the electrical connection joints, inflow lines which send the first cryogenic fluid from the first coolant system to the flow paths, and outflow lines which remove the first cryogenic fluid from the flow paths.

Abstract: A computer-implemented method of optimizing the performance of a reconfigurable power system is provided. The method comprises the steps of: receiving an operating profile for the power system; partitioning the operating profile into a plurality of sub-phases; performing a coarse optimisation routine of the power system over each sub-phase of the operating profile to derive a respective coarsely optimised configuration of the power system; performing a fine optimisation routine of each coarsely optimised configuration over its respective sub-phase of the operating profile to derive a respective finely optimised configuration for that sub-phase; and defining settings of the power system to implement the finely optimised configurations thereon.

Abstract: A storage tank for storing gaseous hydrogen comprises a boundary wall having a laminate composite structure which includes a resin-rich layer forming an internal surface of the boundary wall, a glass-fibre composite layer in contact with the resin-rich layer and a carbon fibre composite layer in contact with the glass-fibre composite layer on a side thereof remote from the resin-rich layer. The laminate structure provides a high level of hydrogen impermeability and resistance to micro-cracking as a result of pressure cycling, providing the tank with a gravimetric efficiency appropriate to aeronautical applications.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, an inlet duct, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter D, and the heat exchanger module comprises a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into the fan assembly. In use, the first fluid has a maximum temperature of 80° C., and the heat exchanger module transfers at least 300 kW of heat energy from the first fluid to the airflow.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D), and the heat exchanger module comprises a plurality of heat exchanger elements. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, with the heat exchanger module having an axial length along a central axis between an upstream-most face of the heat exchanger elements and a downstream-most face of the heat exchanger elements. The axial length is in the range of 0.1*D to 5.0*D.

Abstract: An aircraft comprises a machine body which encloses a turbofan gas turbine engine. The turbofan gas turbine engine includes a heat exchanger module, fan assembly, compressor module, turbine module, and exhaust module. The heat exchanger module communicates with the fan assembly by an inlet duct. The heat exchanger module includes first heat transfer elements that transfer heat energy from a first fluid within the transfer elements to an airflow passing over a surface of the transfer elements before entry of the airflow into a fan assembly inlet. The first fluid contained within transfer elements has a temperature, and the airflow passing over the transfer element surface has a temperature. The turbofan gas turbine engine further includes at least one second heat transfer element, with the or each second heat transfer element transfers heat energy from the first fluid to a second fluid.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly includes a plurality of fan blades defining a fan diameter, and the heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The heat exchanger module includes a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. At full-power condition, the engine produces a maximum thrust T (N), the heat exchanger module transfers a maximum heat rejection H (W) from the first fluid to the airflow, and a Heat Exchanger Performance parameter PEX (W/N) defined as PEX=H/T is 0.4 to 6.0.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly includes fan blades defining a corresponding fan area (AFAN). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and includes radially-extending vanes arranged in a circumferential array with at least one vane including a heat transfer element for heat transfer from a first fluid contained within each element to an airflow passing over a surface of each heat transfer element before entering the fan assembly inlet. Each heat transfer element extends axially along the corresponding vane, with a swept heat transfer element area (AHTE) being the wetted surface area of all heat transfer elements in contact with the airflow. A Fan to Element Area parameter FEA of AHTE/AFAN lies in the range of 47 to 132.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module including a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. Each heat transfer element may be individually and independently fluidly isolated from the remaining heat transfer elements.

Abstract: A turbofan gas turbine engine includes heat exchanger module, fan assembly, compressor, turbine and exhaust modules. The fan includes a plurality of fan blades. The heat exchanger in fluid communicates with the fan assembly by an inlet duct, and the heat exchanger includes a plurality of radially-extending hollow vanes arranged in a circumferential array, with a channel extending axially between each pair of adjacent hollow vanes. An airflow entering the heat exchanger is divided between a set of vane airflows and a set of channel airflows. Each vane airflow has a vane mass flow rate FlowVane, and each channel air flow has a channel mass flow rate FlowChan. Each hollow vane includes, an inlet, heat transfer, and exhaust portions, with the inlet portion comprising a diffuser element and the heat transfer portion including at least one heat transfer element. The diffuser element causes FlowVane to be lower than FlowChan.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter (D). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module includes a plurality of radially-extending hollow vanes arranged in a circumferential array with a channel extending axially between each pair of adjacent hollow vanes. An airflow entering the heat exchanger module is divided between a set of vane airflows through each of the hollow vanes and a set of channel airflows through each of the channels.

Abstract: An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The machine body comprises a single fluid inlet aperture, with the fluid inlet aperture being configured to allow a fluid cooling flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid cooling flow prior to an entry of the entire fluid cooling flow into the fan module.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes fan blades defining a fan diameter. The heat exchanger module is in communication with the fan assembly by an inlet duct, and the heat exchanger module further includes radially-extending hollow vanes arranged in a circumferential array, with a channel extending axially between hollow vanes. Each hollow vane accommodates at least one heat transfer element to transfer heat from a first fluid contained within the or each heat transfer element to a corresponding vane airflow passing through the hollow vane and over a surface of the or each heat transfer element. Each hollow vane further includes a flow modulator configured to regulate airflow in proportion to total airflow entering the heat exchanger module in response to a user requirement.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module comprises a plurality of heat transfer elements. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The inlet duct has a fluid path length along a central axis of the inlet duct between a downstream-most face of the heat transfer elements and an upstream-most face of the fan assembly. The fluid path length is less than 10.0*D.

Abstract: A fuel and oil system includes a fuel pump, an oil pump, and a fixed electrical drive. A first electric motor controller of the fuel and oil system supplies a variable electrical drive, and a second electric motor controller supplies a variable electrical drive. The fuel pump is selectively connected to and driven by the first electric motor controller or the second electric motor controller. The oil pump is selectively connected to and driven by the second electric motor controller or the fixed electrical drive.

Abstract: An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a pressurisation system (102) configured to pressurise the casing above an external pressure to prevent electrical breakdown within gas in the casing.

Abstract: A method of actively controlling torsional resonance of a rotating shaft of an engine is provided. The shaft has a rotational velocity characterised by a low frequency, rotational velocity term and a high frequency, oscillatory term superimposed on the low frequency term, the oscillatory term being caused by torsional resonance. The method including: measuring the rotational velocity of the shaft; extracting the oscillatory term from the measured rotational velocity; and on the basis of the extracted oscillatory term, applying a torque component to the shaft, the torque component being modulated at the same frequency as the torsional resonance to counteract the torsional resonance.

Abstract: A fuel injector comprising a first air swirler passage and a second air swirler passage extending axially through the fuel injector and arranged to direct air through the fuel injector, a splitter arranged between the first air swirler passage and the second air swirler passage and comprising a first splitter surface having a first divergent portion which is divergent in the downstream direction, a second splitter surface located radially inward of the first splitter surface and having a second divergent portion which is divergent in the downstream direction, a third splitter surface located radially inward of the first and second splitter surface, and a first connecting surface extending between the second and third splitter surfaces, wherein a first cavity is formed between the first and second splitter surfaces, and the second divergent portion comprises at least one opening in fluid communication with the first cavity.

Abstract: A system for manufacturing a component includes a build platform, a powder delivery unit, an energy unit, at least one analyser, and a controller. The build platform has a build surface. The powder delivery unit is configured to deposit successive layers of a powdered material on the build surface of the build platform to form a powder bed. The energy unit is configured to selectively direct an energy beam to one or more predetermined portions of each successive layer of the powder bed to fuse the powdered material. The at least one analyser is configured to direct an X-ray beam to the powdered material and detect an X-ray fluorescence emitted by the powdered material in response to being excited by the X-ray beam. The controller is configured to determine a contamination of the powdered material based on the detection of the X-ray fluorescence.

Abstract: A system for mounting a gas turbine engine to a pylon on a wing of an aircraft. A temporary forward link, being length-adjustable, and at least one temporary rearward link, being length-adjustable, are provided. These are for temporarily attaching the gas turbine engine to the pylon. The temporary forward link and the temporary rearward link are each adapted to resist tension and compression, to maintain a positional relationship between the gas turbine engine and the pylon in the absence of adjustment of the lengths of the temporary forward link and the temporary rearward link. Adjustment of the length of the temporary links brings engine mounts into alignment with pylon mounts for service attachment of the gas turbine engine to the pylon.