Abstract: The present application discloses a method of determining one or more fuel characteristics of an aviation fuel suitable for powering a gas turbine engine of an aircraft. The method comprises: determining, during use of the gas turbine engine, one or more exhaust content parameters by performing a sensor measurement on an exhaust of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more exhaust parameters. Also disclosed is a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

Abstract: A rigid link for a flexible robot, the rigid link including a rigid link body having a hollow core, the rigid link with at least two arms having proximal and distal ends, the arms are connected to the rigid link body, and wherein the arms being deployable between a closed configuration in which the proximal and distal ends of the arms are positioned proximate to the rigid link body and open configuration in which the arms are moved so that the distal ends of the arms are positioned away from the body of the rigid link.

Abstract: A method of controlling a propulsion system of an aircraft, the propulsion system comprising a gas turbine engine arranged to be powered by a fuel and at least one variable inlet guide vane—VIGV, comprises obtaining at least one fuel characteristic of the fuel being provided to the gas turbine engine; and making a change to scheduling of the at least one VIGV based on the at least one obtained fuel characteristic.

Abstract: The present application discloses a method of determining one or more fuel characteristics of an aviation fuel used for powering a gas turbine engine of an aircraft. The method comprises: determining one or more performance parameters of the gas turbine engine during a first time period of operation of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more performance parameters. A method of operating an aircraft, a fuel characteristic determination system, and an aircraft are also disclosed.

Abstract: A method of generating a maintenance schedule for an aircraft including one or more gas turbine engines powered by an aviation fuel. The method includes: determining one or more fuel characteristics of the fuel; and generating a maintenance schedule according to the one or more fuel characteristics. Also disclosed is a method of maintaining an aircraft, a maintenance schedule generation system and an aircraft.

Abstract: A variable speed pumping system, for an aircraft, comprising: a first electrical machine, the first electrical machine comprising an electrical machine rotor shaft mechanically connected to an engine of the aircraft and electrical machine stator coils; an electric pump motor-generator, the electric pump motor-generator comprising an electric pump rotor shaft mechanically connected to the electrical machine rotor shaft via a one way drive arrangement and electric pump stator coils; wherein the electric pump rotor shaft is mechanically connected to a fluid pumping system.

Abstract: A gas turbine engine includes: a combustor that combust the fuel and having an exit, a combustor exit temperature (T40) is the average temperature of flow and a combustor exit pressure (P40) is the total pressure there; a turbine including a rotor having a leading edge and a trailing edge, and wherein a turbine rotor entry temperature (T41) is an average temperature of flow at the leading edge and a turbine rotor entry pressure (P41) is the total pressure there; and a compressor having an exit, wherein a compressor exit temperature (T30) is the average temperature of flow at the exit from the compressor and a compressor exit pressure (P30) is the total pressure there (all at cruise conditions). A method of determining at least one fuel characteristic includes changing a fuel supplied to the engine; and determining a change in a relationship between T30 or P30, T40 and T41, or of P40 and P41, respectively.

Abstract: A method of operating an aircraft that includes a propulsion system. The propulsion system includes a gas turbine engine and a fuel tank arranged to provide fuel to the gas turbine engine. The method includes: determining at least one fuel characteristic of the fuel arranged to be provided to the gas turbine engine; and controlling the propulsion system based on the at least one fuel characteristic.

Abstract: A method of operating an aircraft including a gas turbine engine and a plurality of fuel tanks arranged to provide fuel to the gas turbine engine, where at least two of the fuel tanks contain fuels with different fuel characteristics. The method includes obtaining a flight profile for a flight of the aircraft; and determining a fuelling schedule for the flight based on the flight profile and the fuel characteristics. The fuelling schedule governs the variation with time of how much fuel is drawn from each tank. Fuel input to the gas turbine engine may then be controlled in operation in accordance with the fuelling schedule.

Abstract: A continuum arm robot comprising: a tool, a tip section comprising a number of sections a manipulatable robotic section having multiple degrees of freedom, a stiffening section comprising a passive core with an inflatable section surrounding the passive core and a valve for allowing a fluid into the inflatable outer; and a passive section comprising a length of flexible conduit, wherein the core of the passive section and the stiffening section contain the cables for manipulating the tip section and the fluid conduit for supplying the fluid to the inflatable outer.

Abstract: A Z-pin for increasing a delamination resistance of continuous fibre-reinforced polymer composites, formed of a composite material including a polymer matrix, and a plurality of fibres embedded in the polymer matrix and aligned along the length direction of Z-pin, the fibres having an elongation at break of at least 2% and a tensile strength of at least 5 GPa, the polymer matrix having an elongation at break equal to or greater than the elongation at break of the fibres, and a tensile strength of at least 120 MPa.

Abstract: A locking system for a continuum arm robot system, the robot system includes: a continuum arm robot having a manipulatable tip, a passive robot section through which controls for the manipulatable tip, and at least one ferromagnetic collar, and at least one external controllable electromagnetic device which can be activated so that the ferromagnetic section on the continuum arm robot is attracted to the electromagnetic device.

Abstract: An aircraft includes a machine body that encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine includes, in axial flow sequence, a first heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The aircraft includes a second heat exchanger 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 first heat exchanger module. When a temperature of the fluid cooling flow is less than a temperature of a fluid to be cooled, the fluid to be cooled is directed to the first heat exchanger module, and when a temperature of the fluid cooling flow is greater than a temperature of the fluid to be cooled, the fluid to be cooled is directed to the second heat exchanger module and cooled using a fuel supply for the gas turbine engine.

Abstract: Turbomachinery comprising first and second sets of rotors configured to operate on a working fluid. The machinery further comprises first and second sets of electric machines coupled to the respective first and second rotors, and a coupling arrangement arranged to couple adjacent rotors of the first and second rotor sets to provide for fixed ratio, contra-rotation of the first and second rotor sets.

Abstract: A low drag surface is provided for a fluid washed object, the low drag surface comprising an aerodynamic surface comprising a cut-out region, and a continuously translatable surface comprising a surface portion. The surface portion is positioned in the cut-out region such that the aerodynamic surface and the surface portion form a fluidwash surface, and the surface portion is translatable relative to the aerodynamic surface.

Abstract: An electrical system for connecting a rotary electric machine to dc networks operating at different voltages, the electric machine having polyphase winding sets each having a respective index. The electrical system has a first set of ac-dc converter circuits connected in a modular multilevel configuration, each ac-dc converter circuit having a respective index and an ac interface for connection with a corresponding winding set, and in which the modular multilevel configuration has dc outputs each having a respective index. The electrical system also has a set of dc-dc converter circuits each having a respective index and being configured to convert dc power between a voltage at a first dc interface and a voltage at a second dc interface, where a first dc interface of the nth dc-dc converter circuit is connected with the dc outputs of the modular multilevel configuration.

Abstract: Multi-engine aircraft power and propulsion systems and methods of restarting an engine of a multi-engine aircraft during fight are provided. One such method comprises: determining a condition to the effect that a flame in the combustion equipment of the second gas turbine engine has been extinguished; responsive to the determination, supplying electrical power from the electrical energy storage system to one or more of the electric machines of the second gas turbine engine and operating said one or more electric machines as motors to limit a reduction in a speed of the one or more spools of the second gas turbine engine following extinguishment of the flame in its combustion equipment; and restarting the second gas turbine engine by relighting the combustion equipment of the second gas turbine engine.

Abstract: A gas turbine engine for an aircraft comprises, in axial flow sequence, a compressor module, a combustor module, and a turbine module, with a first electric machine being rotationally connected to the turbine module. The first electrical machine is configured to generate a maximum electrical power PEM1 (W), and the gas turbine engine is configured to generate a maximum shaft power PSHAFT (W); and a ratio R of: R = ( Maximum ? Electrical ? Power ? Generated = P E ? M ? 1 ) ( Maximum ? Shaft ? Power = P S ? H ? A ? F ? T ) is in a range of between 0.005 and 0.020.

Abstract: A vane assembly for a gas turbine engine which is a single unitary component that includes an aerofoil. A leading edge passageway is disposed proximal to a leading edge of the aerofoil and configured to receive a flow of a fluid therein. The vane assembly further includes a connecting passageway fluidly communicating the leading edge passageway with a trailing edge distribution passageway that is spaced apart from the leading edge, the leading edge passageway and a trailing edge of the aerofoil. The vane assembly further includes a plurality of trailing edge passageways disposed proximal to a pressure surface of the aerofoil and extending from the trailing edge distribution passageway towards the trailing edge along a chordwise direction. Each trailing edge passageway is configured to discharge the fluid through a corresponding passageway outlet disposed on the pressure surface and in fluid communication with a corresponding trailing edge passageway.

Abstract: An gas turbine engine for an aircraft includes, in axial flow sequence, a compressor module, a combustor module, and a turbine module, together with a first electrical machine rotationally connected to the turbine module. The combustor module has a combustor volume V (cm3). In use, at a full power condition, the gas turbine engine has a maximum corrected core flow Q (m3/sec), and a ratio T of: T = ( Maximum ? Corrected ? Core ? Flow = Q ) ( Combustor ? volume = V ) is in a range of between 450 and 2,500.