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 gas turbine engine comprises a fan coupled to a fan drive turbine, the fan being configured to provide a bypass flow (B) and a core flow (A) in use. The engine includes a reduction gearbox which couples the fan to the fan drive turbine and a core compressor arrangement. The core compressor arrangement has a core inlet at an upstream end of a core gas flow passage (A) defined by radially inner and outer walls, and at least a first compressor rotor blade provided at an upstream end of the compressor arrangement. The radially inner wall of the core inlet defines a first diameter (DINLET), and a root leading edge of the first compressor rotor blade defines a second diameter (DCOMP). A first ratio (DINLET:DCOMP) of the first diameter (DCOMP) to the second diameter (DCOMP) is greater than or equal to 1.4.

Abstract: A gas turbine engine comprising: a combustor configured to initiate combustion; and a turbine comprising a stator vane ring defining a plurality of passageways between adjacent vanes; wherein at least one of the passageways is provided with a restrictor which defines a temporary gas washed surface for the stator vane ring and is configured to be ablated upon initiation of combustion to reveal an operational gas washed surface of the stator vane ring. A method of starting a gas turbine engine is also described.

Abstract: A gas turbine engine (10) includes: a compressor system comprising a low pressure compressor (15) and a high pressure compressor (16) coupled to low pressure and high pressure shafts, respectively (23, 24); an inner core casing (34) provided radially inwardly of compressor blades (42), and an outer core casing provided outwardly of compressor blades, the inner core casing and outer core casing defining a core working gas flow path (B) therebetween; a fan (13) coupled to the low pressure shaft via a gearbox (14); wherein the outer core casing comprises a first outer core casing (48) and a second outer core casing (50) spaced radially outwardly from the first outer core casing, and wherein at an axial plane (E) of an inlet to the high pressure compressor, the second outer core casing has an inner radius at least 1.4 times the inner radius of the first outer core casing.

Abstract: A supersonic jet aircraft and a method of operating the same. The supersonic jet aircraft having at least three turbofan engines and an engine management computer. A first engine of the at least three turbofan engines is configured to be de-activatable during flight to move from an operational state in which it provides thrust to an operational state in which it stops providing thrust. Other engines of the at least three turbofan engines are configured to provide sufficient thrust to the supersonic jet aircraft when the first engine is de-activated such that the aircraft can perform a supersonic climb operation and/or a supersonic cruise operation.

Abstract: A propulsion system includes a main gas turbine engine adapted for generating propulsive thrust during subsonic and supersonic flight operations and a supplementary propulsion unit adapted for generating additional thrust. The supplementary propulsion unit has an air intake and an exhaust for gas accelerated by the supplementary propulsion unit to provide the additional thrust and is adapted to generate the additional thrust during a limited range of subsonic flight operations, and to be dormant during other flight operations. The propulsion system has housing for the supplementary propulsion unit, including intake and exhaust covers which are moveable between deployed and stowed configurations. During the limited range of subsonic flight operations the intake and exhaust cover are moved to the deployed configuration to open the intake and the exhaust. During other flight operations the intake and exhaust cover are moved to the stowed configuration to close the intake and the exhaust.

Abstract: An aircraft gas turbine engine comprises a fan coupled to a fan drive turbine, the fan being configured to provide a bypass flow (B) and a core flow (A) in use. The engine includes a reduction gearbox which couples the fan to the fan drive turbine and a core compressor arrangement. The core compressor arrangement has a core inlet at an upstream end of a core gas flow passage (A) defined by radially inner and outer walls, and at least a first compressor rotor blade provided at an upstream end of the compressor arrangement. The radially inner wall of the core inlet defines a first diameter (DINLET), and a root leading edge of the first compressor rotor blade defines a second diameter (DCOMP). A first ratio (DINLET:DCOMP) of the first diameter (DCOMP) to the second diameter (DCOMP) is greater than or equal to 1.4.

Abstract: A gas turbine engine (10) includes: a compressor system comprising a low pressure compressor (15) and a high pressure compressor (16) coupled to low pressure and high pressure shafts, respectively (23, 24); an inner core casing (34) provided radially inwardly of compressor blades (42), and an outer core casing provided outwardly of compressor blades, the inner core casing and outer core casing defining a core working gas flow path (B) therebetween; a fan (13) coupled to the low pressure shaft via a gearbox (14); wherein the outer core casing comprises a first outer core casing (48) and a second outer core casing (50) spaced radially outwardly from the first outer core casing, and wherein at an axial plane (E) of an inlet to the high pressure compressor, the second outer core casing has an inner radius at least 1.4 times the inner radius of the first outer core casing.

Abstract: An aircraft gas turbine engine comprises a high pressure compressor coupled to a high pressure turbine by a high pressure shaft, and a low pressure compressor coupled to a low pressure turbine by a low pressure shaft. The engine includes a first shaft bearing configured to support a forward end of the low pressure shaft, the first shaft bearing being mounted to a static structure forward of the high pressure turbine. The engine also includes a second shaft bearing configured to support a rearward end of the low pressure shaft, the second shaft bearing being mounted to a static structure rearward of the high pressure turbine, and forward of the low pressure turbine. The engine further includes a third shaft bearing configured to support the low pressure shaft, the third shaft bearing being mounted to a static structure rearward of the low pressure turbine.

Abstract: A gas turbine engine (10) comprising: a low pressure turbine (19); a fan (13) drivable by the low pressure turbine. A high pressure turbine (18) and a high pressure compressor (16) coupled by a high pressure shaft (24). An epicyclic gearbox (14) in planetary configuration coupled between a low pressure shaft (23) and the fan. The engine having a bypass ratio greater than or equal to 13. Or the fan having a diameter greater than or equal to 85 inches and less than or equal to 170 inches. Or the engine arranged to generate thrust in the range 35,000 lbf to 130,000 lbf.

Abstract: An aircraft gas turbine engine includes a fan arranged to be driven by a gas turbine engine core. The core includes a first core module including a first compressor and a fan drive turbine interconnected by a first shaft, and a second core module including a second compressor and a second turbine interconnected by a second shaft, the first and second core modules being axially spaced. The gas turbine engine further includes an intercooler arrangement configured to cool core airflow between the first and second compressors, the intercooler arrangement including a cooling air duct provided in heat exchange relationship with a compressor duct provided between the first and second compressors, the cooling air duct including a fan air inlet configured to ingest fan air downstream of the fan, wherein the cooling air duct includes a flow modulation valve configured to modulate air mass flow through the fan air inlet.

Abstract: An aircraft gas turbine engine (110) comprises first and second non-coaxial propulsors (113a, 113b), each propulsor (113a, 113b) being driven by a common gas turbine engine core (176) comprising a propulsor drive turbine (143) arranged to drive the first and second propulsors (113a, 113b) via a propulsor drive coupling (127). The core (176) further comprises a first core module (190) comprising a first compressor (129) and a first turbine (131) interconnected by a first shaft (177), and a second core module (191) comprising a second compressor (128) and the propulsor drive turbine (143) interconnected by a second shaft (127), the first and second core modules (190, 191) being axially spaced.

Abstract: A propulsive fan system comprises a fan unit comprising a first stage array of rotatable blades upstream of a second stage array of rotatable blades. The first stage is coupled to a first drive means. The second stage is coupled to a second drive means. The first drive means is independently operable of the second drive means during operation of the fan system.

Abstract: A system and method for variable drive of a propeller or fan of a gas turbine engine. The gas turbine engine has a combustor and a turbine arranged to be driven by a combustion product from the combustor. The variable drive system comprises a primary shaft arranged for transmission of torque from said turbine to the propeller; an electric generator arranged to be driven by said turbine; and an electric motor arranged to be driven by the output of said generator. A clutch is mounted between the propeller and the primary rotor and is operable to mechanically disconnect the shaft from the propeller so that the propeller can be driven by any or any combination of the turbine and/or electric motor. The invention may be applied to a turboprop or turbofan engine having a gearing between the shaft and propeller or fan and may be particularly suited to unmanned aerial vehicle propulsion.

Abstract: A bypass turbofan gas turbine engine is started by means of electric starter motor mounted directly about a downstream end or upstream of the low pressure spool of the engine. This causes air to be driven by a fan through a bypass duct around the engine casing. Closures close to substantially seal an outlet of the bypass duct, and the air is directed into a combustion chamber of the engine and through the turbines, causing the high pressure spool to pick up speed for starting.

Abstract: A propulsive fan system comprises a fan unit comprising a first stage array of rotatable blades upstream of a second stage array of rotatable blades. The first stage is coupled to a first drive means. The second stage is coupled to a second drive means. The first drive means is independently operable of the second drive means during operation of the fan system.

Abstract: A system and method for variable drive of a propeller or fan of a gas turbine engine. The gas turbine engine has a combustor and a turbine arranged to be driven by a combustion product from the combustor. The variable drive system comprises a primary shaft arranged for transmission of torque from said turbine to the propeller; an electric generator arranged to be driven by said turbine; and an electric motor arranged to be driven by the output of said generator. A clutch is mounted between the propeller and the primary rotor and is operable to mechanically disconnect the shaft from the propeller so that the propeller can be driven by any or any combination of the turbine and/or electric motor. The invention may be applied to a turboprop or turbofan engine having a gearing between the shaft and propeller or fan and may be particularly suited to unmanned aerial vehicle propulsion.

Abstract: A gas turbine engine (2) comprises a fan unit (4,18,36,42,44,46) in flow relationship with an engine core and a bypass duct, of which said engine core and bypass duct (16) are in parallel flow relationship with each other. The engine core comprises a compressor (6), a combustor (8) and a turbine (10), with an inner casing (12) provided around said engine core which defines the engine core intake (32). The bypass duct (16) is defined by an outer casing (14) radially spaced apart from the fan unit (4,18,36,42,44,46) and the inner casing (12) along at least part of the length of the gas turbine engine (2). Bypass air compression means (28) are provided such that, under substantially all engine power conditions, air at exit from the bypass duct (16) is at a greater pressure than air delivered to the engine core intake (32).