Abstract: An aircraft hybrid propulsion system (5) comprises an internal combustion engine (10) comprising a main drive shaft (24), an electric machine (28) comprising an electric machine rotor (78), a propulsor (12) mounted to a propulsor shaft (62), and a clutch arrangement configured to selectively couple each of the gas turbine engine main drive shaft (24) and electric machine rotor (78) to the propulsor drive shaft (62). The electric machine rotor (78) is mounted coaxially with the main drive shaft (24) and the clutch arrangement comprises a first overrunning clutch (52) configured to couple the main drive shaft (24) to the propulsor drive shaft (62), and a second overrunning clutch (54) configured to couple the electric machine rotor (78) to the propulsor drive shaft (62).

Abstract: The present disclosure concerns an electric aircraft propulsion system. Example embodiments include an aircraft propulsion system (200) comprising: a fan (213) mounted on a central shaft (214); a first electric motor (215) mounted on the central shaft (214) and arranged to drive rotation of the fan (213) via the central shaft; and a second electric motor (216) arranged to drive rotation of the fan (213) via the central shaft (214), wherein the second electric motor (216) is coaxially mounted downstream of the first electric motor (215) and an outer diameter (D2) of the second electric motor (216) is smaller than an outer diameter (D1) of the first electric motor (215).

Abstract: An aircraft hybrid propulsion system comprises an internal combustion engine, an electric motor a propulsor and a combining gearbox. The internal combustion engine is coupled to a first input of the combining gearbox, the electric motor is coupled to a second input of the combining gearbox, and the propulsor is coupled to an output of the combining gearbox, such that the propulsor is driveable in use by either or both of the internal combustion engine and the electric motor. Each of the internal combustion engine and the electric motor is coupled to its respective input by a respective clutch.

Abstract: An aircraft propulsion system comprises a vertical lift propulsor mounted within a wing of the aircraft. The vertical propulsor comprises an electric motor comprising a rotor mounted to a plurality of propulsor blades, the motor further comprising a stator. The rotor is provided radially outwardly of the stator.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a tip speed of from 1 to 3 times that of the outer fan.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a rate of rotation of from 3 to 8 times that of the outer fan.

Abstract: An aircraft propulsion system comprises first and second co-axial propulsors, one of the first and second propulsor being positioned forward of the other propulsor. A first electric motor is configured to drive the first propulsor, and a second electric motor is configured to drive the second propulsor. The first electric motor comprising a rotor radially inwardly of the stator, and the second electric motor comprises a rotor radially outwardly of the stator. The stator of the first electric motor is mounted to the stator of the second electric motor.

Abstract: A star-configuration epicyclic gearbox is shown. It comprises a sun gear (112) for connection with a first shaft (112), a plurality of planet gears (113) intermeshed with the sun gear and located in a static carrier (114), and a ring gear (115) for connection with a second shaft (116) and which is intermeshed with the plurality of planet gears. It further comprises one or more electric machines (117) drivingly connected with a respective one of the plurality of planet gears.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The outer fan has a diameter of from 2.5 to 3.5 times a diameter of the inner fan.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. A swept area of the outer fan is from 2 to 20 times greater than a swept area of the inner fan.

Abstract: An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. A hub-tip ratio of the outer fan is from 1.6 to 2.2 times a hub-tip ratio of the inner fan.

Abstract: An electric ducted fan for an aircraft is shown. A nacelle defines a duct that houses a propulsive fan having a fan diameter DF. An electric machine is configured to drive the fan, and has an electromagnetically active length LA and an electromagnetically active diameter DA defining an aspect ratio (LA/DA) of from 0.8 to 2. A speed reduction device is located between the electric machine and the fan, and has a reduction ratio of at least 3:1. A ratio of the electromagnetically active diameter DA to the fan diameter DF (DA/DF) is from 0.3 to 0.5.

Abstract: An electric ducted fan for an aircraft is shown. A nacelle defines a duct that houses a propulsive fan having a fan diameter DF. An electric machine is configured to drive the fan, and has an electromagnetically active length LA and an electromagnetically active diameter DA defining an aspect ratio (LA/DA) of from 0.8 to 2. A ratio of the electromagnetically active diameter DA to the fan diameter DF (DA/DF) is from 0.45 to 0.60.

Abstract: An aircraft hybrid propulsion system (5) comprises an internal combustion engine (10) comprising a main drive shaft (24), an electric machine (28) comprising an electric machine rotor (78), a propulsor (12) mounted to a propulsor shaft (62), and a clutch arrangement configured to selectively couple each of the gas turbine engine main drive shaft (24) and electric machine rotor (78) to the propulsor drive shaft (62). The electric machine rotor (78) is mounted coaxially with the main drive shaft (24) and the clutch arrangement comprises a first overrunning clutch (52) configured to couple the main drive shaft (24) to the propulsor drive shaft (62), and a second overrunning clutch (54) configured to couple the electric machine rotor (78) to the propulsor drive shaft (62).

Abstract: An aircraft hybrid propulsion system comprises an internal combustion engine, an electric motor a propulsor and a combining gearbox. The internal combustion engine is coupled to a first input of the combining gearbox, the electric motor is coupled to a second input of the combining gearbox, and the propulsor is coupled to an output of the combining gearbox, such that the propulsor is driveable in use by either or both of the internal combustion engine and the electric motor. Each of the internal combustion engine and the electric motor is coupled to its respective input by a respective clutch.

Abstract: A gas turbine engine, and arrangements of turbine blades around an exhaust nozzle of an engine core. Example embodiments include a gas turbine engine for an aircraft comprising: an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor, the engine core comprising an inlet upstream of the compressor and an exhaust nozzle at a downstream outlet of the turbine; a fan located upstream of the engine core inlet; and a set of exhaust nozzle vanes spanning the exhaust nozzle, the turbine comprising a first row of turbine blades upstream of the exhaust nozzle vanes and a second row of turbine blades downstream of the exhaust nozzle guide vanes, one or more of the exhaust nozzle guide vanes comprising a passage configured to direct airflow downstream from the first row of turbine blades towards the second row of turbine blades.

Abstract: A planet carrier for an epicyclic gearbox, the planet carrier comprising: a single piece carrier body arranged to support a plurality of gears of the epicyclic gearbox; and an opening in a wall of the carrier body; wherein: in a cross-section of the carrier body in a plane that is orthogonal to the longitudinal axis of the carrier body and at a longitudinal position along the carrier body that does not comprise the opening, the carrier body is substantially annular; and the opening is arranged such that the gears that the carrier body is arranged to support can be passed entirely through the opening.

Abstract: An electric motor generator system has a hollow rotatable shaft, a coil spar, and a plurality of magnet portions. The hollow rotatable shaft has a central longitudinal axis. The coil spar comprises one or more coil assemblies and is positioned concentrically within the hollow rotatable shaft. Each of the magnet portions is shaped to conform to a radially inwardly facing surface of the shaft. Each of the plurality of magnet portions abuts conformally against the radially inwardly facing surface of the shaft between the radially inwardly facing surface and the or each coil assembly.

Abstract: A vehicle propulsion system comprises a first propulsor and a second propulsor. The first and second propulsors are coupled to an electric machine comprising a stator and first and second rotors. Each of the first and second rotors are electromagnetically coupled to the stator. The first rotor is coupled to the first propulsor and the second rotor is coupled to the second propulsor.

Abstract: A planet carrier for an epicyclic gearbox, the planet carrier comprising: a single piece carrier body arranged to support a plurality of gears of the epicyclic gearbox; and an opening in a wall of the carrier body; wherein: in a cross-section of the carrier body in a plane that is orthogonal to the longitudinal axis of the carrier body and at a longitudinal position along the carrier body that does not comprise the opening, the carrier body is substantially annular; and the opening is arranged such that the gears that the carrier body is arranged to support can be passed entirely through the opening.