Abstract: A nozzle for a gas turbine engine. An array of convergent petals hingedly coupled to a nozzle exit of fixed diameter. An array of divergent petals, each divergent petal hingedly coupled to one of the array of convergent petals. A cam surface associated with the array of convergent petals. A pivot point coupled to the array of divergent petals by a first linkage and to a fixed point by a second linkage. A cam follower coupled to the second linkage by a third linkage, the cam follower arranged to abut and travel in contact with the cam surface. An actuator coupled to the cam follower and arranged to translate the cam follower along the cam surface to move the convergent and divergent petals.

Abstract: A fan nacelle for an aircraft gas turbine engine. The nacelle includes an aft nacelle portion including a radially outer surface and a radially inner surface, the radially outer and inner surfaces defining an internal cavity therebetween. The nacelle further includes an aft nacelle segment translatable along a translation vector having an axial component, wherein the aft nacelle segment is configured to translate between a forward deployed position in which the nacelle defines a first primary fan nozzle exit area (A1) and a clean position in which the nacelle defines a second primary fan nozzle exit area (A2) less than the first primary fan nozzle exit area A1, wherein in the forward deployed position, the aft nacelle segment is at least partly located within the internal cavity.

Abstract: A vane cooling system for a gas turbine engine comprises a vane (21) arranged on a stator and having a chamber (23) extending continuously from a radially inner end to a radially outer end of the vane. The vane (21) has; a radially inner inlet (24) and a radially outer inlet (25), a first cooling fluid feed (39) in communication with the radially inner inlet (24) and a second cooling fluid feed (28) in communication with the radially outer inlet (25), The first cooling fluid feed (39) has a higher pressure than the second cooling feed (28). A flow adjustment device (30) is arranged for adjusting a flow of the second cooling fluid feed into the radially outer inlet (25).

Abstract: Producing a component having an in use gas washed surface includes: obtaining a reference component having a reference shape with an in use gas washed surface; setting one or more performance threshold for the reference shape, the threshold defining an acceptable performance for the reference shape; obtaining a manufactured component made to the reference shape; measuring the manufactured component and determining a displacement distribution indicative of the geometric deviation of the manufactured component from the reference shape; determining a performance sensitivity distribution for the reference component, the sensitivity distribution having a plurality of points, each point indicative of a performance factor for the reference component; combining the sensitivity distribution and displacement distribution to determine a performance prediction for the manufactured component; determining whether the performance prediction is within the performance threshold; accepting or rejecting the component for use if

Abstract: An aerofoil body for a gas turbine engine is provided. The aerofoil body has leading and trailing edge portions, wherein one of the leading and trailing edge portions is a morphable edge portion having a composite layer structure. The aerofoil body further has a non-morphing central portion which forms pressure and suction surfaces of the aerofoil body between the leading and trailing edge portions. The composite layer structure includes a return spring, one or more shape memory alloy layers, and a flexible cover for the return spring and the one or more shape memory alloy layers. The flexible cover defines pressure and suction surfaces of the aerofoil body at the morphable edge portion. The one or more shape memory alloy layers are electrically heatable to deform the layers against the resistance of the return spring, and thereby alter the pitch of the aerofoil body at the morphable edge portion.

Abstract: An actuation system 100 comprises a fluid supply 130 that is fluidly connected to a position control actuator 110. The output of the position control actuator is determined by the fluid supply. The fluid supply is controlled by a piezoelectric actuator 150.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (rhub) to a tip defining a 100 percent span position (rtip) and a plurality of span positions therebetween (r?[rhub, rtip]). A plurality of outlet guide vanes are positioned aft of the fan. An afterbody is located aft of the plurality of outlet guide vanes and which tapers to an apex having an apex angle with respect to the rotational axis of between 35 and 45 degrees.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (rhub) to a tip defining a 100 percent span position (rtip) and a plurality of span positions therebetween (r?[rhub, rtip]). The hub has a negative hade angle (?) with respect to the rotational axis at an axial o position coincident with the leading edge of the blades.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft includes a nacelle (501) defining a duct (502), and a fan (503) located therewithin. The fan comprises a hub which rotates around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r ?[0, 1]), a leading edge and a trailing edge defining, for each span position, a chord therebetween having a chord length (c), and a blade thickness (t) defined for each span position thereof. For each blade, a ratio of thickness at the 0 percent span position (thub) to chord length is 0.1 or greater.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle (501) defining a duct, and a fan located therewithin. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r ? [0, 1]), and leading and trailing edges defining, for each span position, a chord therebetween to having a chord length (c). For each of said plurality of blades, the ratio of chord length at the 0 percent span position (chub) to chord length at the 100 percent span position (ctip) is 1 or greater.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (rhub) to a tip defining a 100 percent span position (rtip) and a plurality of span positions therebetween (r?[rhub, rtip]). A hub-tip ratio of the fan, defined as the ratio of the diameter of the hub to the diameter of the fan measured at the leading edge of the blades, is from 0.45 to 0.55.

Abstract: Method of reducing the thickness of a bore of a cylindrical workpiece for use as a gear. The method involves the steps of: mounting a cylindrical workpiece having a horizontal central axis and an outer diameter in a grinding machine; and grinding the bore of the cylindrical workpiece to reduce its thickness using a grinding wheel that has a diameter that is from 40% to 80% of the outer diameter of the cylindrical bore and has a direction of rotation about an axis of rotation that is parallel to the horizontal central axis of the cylindrical workpiece. The axis of rotation of the grinding wheel may be located from 90 degrees to 180 degrees, in the direction of rotation of the grinding wheel, from a plane that extends vertically through the workpiece when it is mounted in the grinding machine. The gear may be one of a planetary, sun, parallel axis or helical gear.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle (501) defining a duct (502), and a fan (503) located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r ? [0, 1]), and a stagger angle at the 0 percent span position (?hub) relative to the rotational axis of 40 degrees or greater.

Abstract: A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub. A blade blockage, which is the ratio of the blade thickness to the product of the circumferential pitch and the cosine of a blade inlet angle (t/s·cos?1), is 0.25 or greater at the 0 percent span position.

Abstract: A gas turbine engine includes a turbine and a turbine cooling arrangement. The turbine includes a turbine rotor surrounded by a static rotor track liner, and a nozzle guide vane downstream of the rotor in a core main gas flow path. The cooling arrangement includes a first air duct that provides cooling airflow to a rotor track liner cooling plenum and a second air duct that provides a cooling airflow to the nozzle guide vane. A common manifold is upstream in the cooling airflow of the ducts and provides cooling air to the ducts. A two-way valve modulates air provided to the ducts from the manifold. The valve is operates in a first or second mode. In the first mode, air flow to the first duct is relatively high and airflow to the second duct is relatively low compared to where the valve is operated in the second mode.

Abstract: In accordance with some embodiments, the present disclosure is directed to systems having a fuel cell and a turbine generator, each capable of providing electrical power to a utility grid, and methods for operating the same. The system may have a main AC bus which is coupleable to the utility grid. The fuel cell may be coupled to main AC bus through an inverter. The turbine generator may be coupled to the main AC bus through a series of inverters, one of which may include the inverter by which the fuel cell is connected to the main AC bus. One or more load banks may be provided to provide a load for electrical power generated from the fuel cell, turbine generator, or both in case the system is disconnected from the utility grid. Further support and backup systems may be provided.

Abstract: A gas turbine engine combustion chamber includes upstream and downstream ring structures and a plurality of circumferentially arranged combustion chamber segments. Each segment extends the full length of the combustion chamber and each segment is secured to the upstream ring structure and is mounted on the downstream ring structure. The upstream end of each combustion chamber segment includes a surface having a plurality of circumferentially spaced radially extending holes and the upstream ring structure having a plurality of circumferentially spaced holes extending radially through a portion abutting the surface of the upstream end of each combustion chamber segment. Each combustion chamber segment being removably secured to the upstream ring structure by a plurality of fasteners locatable in the holes in the combustion chamber segment and corresponding holes in the upstream ring structure.

Abstract: An aerofoil having a leading edge and a trailing edge, the leading edge including a plurality of slits extending toward the trailing edge, such that the leading edge is defined by alternating peaks and troughs. Each peak extends in a generally spanwise direction and defines a peak width, each peak being separated from an adjacent peak in the spanwise direction by a trough. Each trough extends in the generally spanwise direction and is spaced in a chordwise direction from the peak, each trough defining a trough width. A ratio of the peak width to the trough width is between 4:1 and 10:1.

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 bladed disc comprising a disc hub 110; a set of blades 120 angularly distributed around the disc hub; wherein there is variation in a geometric parameter between the blades. The blades are positioned around the disc hub such that for a majority of pairs of neighbouring blades in the set, an interval between values of the geometric parameter between the blades of the pair is less than 0.5 standard deviations of the geometric parameter for the set of blades.