Abstract: A gas turbine engine for an aircraft including: an engine core; a fan located upstream of engine core, fan including a plurality of fan blades; a nacelle surrounding the gas turbine engine, nacelle including an inner surface at least partly defining a bypass duct; and a bypass duct outlet guide vane extending radially across bypass duct between the engine core's outer surface and the nacelle's inner surface. An outer wall axis is defined joining a radially outer tip of a trailing edge of the bypass duct outlet guide vane and a rearmost tip of the inner surface of the nacelle, wherein the outer wall axis lies in a longitudinal plane containing the centreline of gas turbine engine, an outer bypass duct wall angle is defined as the angle between outer wall axis and centreline, and the outer bypass duct wall angle is in a range between ?15 to 1 degrees.

Abstract: A gas turbine engine for an aircraft including: engine core including a turbine; and fan including a plurality of fan blades extending radially from a hub, each fan blade having a leading and trailing edge. Turbine includes a lowest pressure turbine stage having a row of rotor blades each extending radially and having a leading and trailing edge. A fan-turbine radius difference is measured as radial distance between: a point on a circle swept by a radially outer tip of the trailing edge of each of the rotor blades of the lowest pressure stage of the turbine; and a point on a circle swept by a radially outer tip of the leading edge of each of fan blades; and a fan speed to fan-turbine radius ratio defined as: the ? ? maximum ? ? take ? - ? off ? ? rotational ? ? speed ? ? of ? ? the ? ? fan fan ? - ? turbine ? ? radius ? ? difference ? ? ( 120 ) is in a range between 0.8 rpm/mm to 5 rpm/mm.

Abstract: A gas turbine engine for an aircraft includes an engine core including a turbine, compressor, and core shaft connecting turbine to compressor; a fan located upstream of the engine core and including a plurality of fan blades each having a leading and trailing edge. The turbine includes a lowest pressure turbine stage having a row of rotor blades, each rotor blades extending radially and having a leading and trailing edge. The engine has a fan tip axis that joins a radially outer tip of the leading edge of a fan blade and the radially outer tip of the trailing edge of a rotor blade of the lowest pressure stage. The fan tip axis lies in a longitudinal plane which contains a centreline of engine. A fan axis angle is defined as the angle between fan tip axis and centreline, and is in a range between 10 and 20 degrees.

Abstract: A gas turbine engine of an aircraft includes: an engine core having a turbine including a lowest pressure rotor stage, a turbine diameter, a fan including a plurality of fan blades extending from a hub, an annular fan face at a leading edge of the fan; wherein a downstream blockage ratio is: the ? ? turbine ? ? diameter ? ? at ? ? an ? ? axial location ? ? of ? ? the ? ? lowest ? ? pressure ? ? rotor ? ? stage ? ground ? ? plane ? ? to ? ? wing ? ? distance and a quasi-non-dimensional mass flow rate Q defined as: Q = W ? T ? ? 0 P ? ? 0 · A flow where: W is mass flow rate through the fan in Kg/s; T0 is average stagnation temperature of the air at the fan face in Kelvin; P0 is average stagnation pressure of the air at the fan face in Pa; and Aflow is the flow area of the fan face in m2, and wherein a Q ratio of: the downstream blockage ratio×Q is in a range from 0.005 to 0.01.

Abstract: There is disclosed a gas turbine engine for an aircraft comprising: a propulsive fan having a plurality of fan blades; a fan casing; and an air intake; wherein the air intake is mechanically coupled to the fan casing at a point having an axial position that is within a range of axial positions from a first axial position that is rearward of the leading edge of the fan blade at its radial tip by an axial component of a blade chord length, to a second axial position that is forward of the leading edge of the fan blade tip by an axial component of the blade chord length.

Abstract: A gas turbine engine (10) comprises a bypass duct cowl (21), an engine core housing (22) defining an engine core inlet, a bypass fan (13) and a plurality of outlet guide vanes (24). Each outlet guide vane 24 extends between a radially inner surface of the bypass duct cowl (21) and a radially outer surface of the engine core housing (22, 23) to define an outlet guide vane span (SPANOGV). The outlet guide vanes (24) are configured to support the engine core housing (22, 23) relative to the bypass duct cowl (21). The bypass fan (13) and an engine core inlet (34) define a bypass ratio between 10 and 17, and a ratio of the outlet guide vane span (OGVSPAN) to a bypass fan radius (RFAN) is between 0.45 and 0.55.

Abstract: A mounting arrangement for mounting an aircraft gas turbine engine to an aircraft includes an engine nacelle with a distal assembly including a part annular engine cowl, a gas turbine engine core housing surrounded by the cowl and a distal bifurcation extending between the engine core housing and engine cowl in a first direction to define a first axis. The mounting arrangement includes a proximal assembly having a mount configured to mount the proximal assembly to the engine core housing. The proximal assembly includes a pylon configured to mount the proximal assembly to mounting location such as a wing of the aircraft at an engine mounting location. The pylon extends in a line between the wing and the engine core housing to define a second axis which is normal to a distal surface of the wing at the engine mounting location and is non-parallel to the vertical axis.

Abstract: An aircraft gas turbine engine nacelle comprises a thrust reversal arrangement. The thrust reversal arrangement comprises at least first and second circumferentially spaced fixed thrust reverser cascade boxes each comprising a plurality of thrust reverser vanes configured to direct air forwardly and circumferentially and at least one inter-leaved translating circumferential turning vane configured to direct air in a direction having a circumferential component. The circumferential turning vane is moveable from a stowed position provided between the first and second circumferentially spaced thrust reverser cascade boxes, and a deployed position axially rearwardly of the thrust reverser cascade boxes.

Abstract: Apparatus for a gas turbine engine, the apparatus comprising: a core engine casing having a longitudinal axis and including: an inner wall defining at least part of a core airflow path through the gas turbine engine; an outer wall defining an external surface of the core engine casing, a first cavity being defined between the inner wall and the outer wall of the core engine casing; a plurality of guide vanes extending radially from the outer wall of the core engine casing; a torque box defined within the first cavity of the core engine casing and at least partially overlapping axially with the plurality of guide vanes, the torque box defining a second cavity; and an accessory gear box positioned within the second cavity of the torque box.

Abstract: A gas turbine engine (100) for an aircraft comprises a pylon attachment (112) and a shaft (108) defining an engine centreline (110). The engine centreline lies in an engine central plane (120) which intersects the pylon attachment. The gas turbine engine comprises an intake (104) having a non-axisymmetric geometry and a medial plane (130) defining left and right halves of the intake. The left and right halves are configured for at least one of optimum cross wind performance, optimum incidence performance and optimum cruise performance when the medial plane is aligned with a vertical plane. The intake is installed so that the medial plane is angularly offset with respect to the engine central plane. The engine may be installed on a wing of an aircraft with the medial plane closer to its optimal orientation than is the case for a conventional engine.

Abstract: A gas turbine engine comprises a pylon attachment, a shaft defining an engine centreline which lies in an engine central plane intersecting the pylon attachment, a fan defining a fan plane normal to the engine centreline and an intake upstream of the fan plane. The geometric centreline of the intake coincides with the engine centreline at an axial position corresponding to the downstream end of the intake and curves away from the engine centreline upstream of said axial position. The engine may be mounted on one side of an aircraft such that the orientation of the highlight plane of the intake is aligned to the air flow field of the aircraft on that side during flight.

Abstract: A gas turbine engine comprising a planetary gear train, and a core engine casing. The gear train has a ratio of greater than approximately 3.0, with an input to the gear train being operatively connected to the compressor section, and an output from the gear train being operatively connected to the fan. The core engine casing encloses the compressor section and the turbine section. The fan has a diameter F, and the core engine casing has a diameter C. The core engine casing diameter C varies along an axial length of the core engine casing, and a ratio (C/F) of the core engine casing diameter C to the fan diameter F is within the range 0.2<(C/F)<0.4, along an axial length of the core engine casing.

Abstract: A gas turbine engine (10) for an aircraft (90) comprises an engine core (11, 60) comprising a turbine (19), a compressor (14), and a core shaft (26) connecting the turbine to the compressor; an engine casing (61) arranged to at least partially surround the engine core (11), the engine casing comprising at least one first elongate formation (67) on its outer surface, the first elongate formation extending in an axial direction; and a housing (55) arranged to surround the engine core (11, 60), the housing (55) comprising at least one second elongate formation (57) on an inner surface of the housing, the second elongate formation (57) extending in the axial direction. The engine casing (61) is detachably connected to the housing (55) by interengagement of the first and second elongate formations (57, 67).

Abstract: An aircraft gas turbine engine nacelle comprises a thrust reversal arrangement. The thrust reversal arrangement comprises at least first and second circumferentially spaced fixed thrust reverser cascade boxes each comprising a plurality of thrust reverser vanes configured to direct air forwardly and circumferentially and at least one inter-leaved translating circumferential turning vane configured to direct air in a direction having a circumferential component. The circumferential turning vane is moveable from a stowed position provided between the first and second circumferentially spaced thrust reverser cascade boxes, and a deployed position axially rearwardly of the thrust reverser cascade boxes.

Abstract: The present disclosure relates to a propfan engine comprising: one or more rotor stages comprising a plurality of rotors; and an outer wall comprising an outer profile, at least a portion of the outer profile defining a substantially circular cross-section, wherein the diameter of the substantially circular cross-section increases in the direction of flow over the outer wall and downstream of a leading edge of the rotors, and the diameter increases at substantially all points defining the circumference of the substantially circular cross-section.

Abstract: A heat exchanger arrangement for a gas turbine engine. The arrangement including a flow path within an outer cowl, which flow path locates a heat exchanger part way therealong. A valve is provided at an inlet end of the flow path to selectively receive fluid into the flow path from outside of the cowl and/or from a pressurized fluid flow. An exit from the flow path includes a plenum chamber to receive exhausted coolant flows from the heat exchanger and possibly other exhaust flows. The heat exchanger exhaust flow is then utilized to provide cooling to engine structures.

Abstract: The present disclosure relates to a propfan engine comprising: one or more rotor stages comprising a plurality of rotors; and an outer wall comprising an outer profile, at least a portion of the outer profile defining a substantially circular cross-section, wherein the diameter of the substantially circular cross-section increases in the direction of flow over the outer wall and downstream of a leading edge of the rotors, and the diameter increases at substantially all points defining the circumference of the substantially circular cross-section.

Abstract: A duct wall of a fan casing of a gas turbine engine comprises an intake section and a containment casing, which are interconnected by bolts at flanges. An acoustic flutter damper is provided between the flanges to reduce or eliminate flutter arising in blades of the fan at certain important operating conditions. The damper provides flexibility at the connection between the intake section and the containment casing so that, in the event of detachment of a blade or a bladed fragment, the resulting deflection wave in the containment casing can be accommodated by displacement and/or deformation of the acoustic flutter damper, reducing the risk that the bolts will shear to allow the intake section and the containment casing to become detached from each other. The acoustic flutter damper may comprise a circumferential array of separate segments.

Abstract: Variation in the available mixing plane areas in an exhaust arrangement of a gas turbine engine enables alteration and configuration for better thermal cycle performance of that engine. A shaped centre fairing is associated with an exit nozzle and a bypass duct such that channels between the fairing, nozzle exit and duct can be adjusted to change the available areas. Such variation is achieved by relative axial displacement, typically of the exit nozzle using an appropriate mechanism.

Abstract: A support structure is provided for attaching a gas turbine engine to a pylon. The gas turbine engine has an engine casing surrounding an engine core, and the pylon has first and second attachment positions, the second attachment position being forward of the first attachment position relative to the working gas flow direction through the engine. The support structure has three elongate members joined to form a triangular frame encircling the engine casing. A first vertex of the triangular frame attaches to the pylon via a first attachment arrangement at the first attachment position. Two thrust struts respectively extend from the other two vertices of the triangular frame and attach to the pylon via a second attachment arrangement at the second attachment position. Three engine connection formations extend from the respective vertices of the triangular frame to positions on the engine casing to connect the support structure to the engine casing.