Abstract: A ducted fan gas turbine engine has a propulsive fan, a fan case surrounding the fan, a core engine, and a plurality of support structures which transmit loads from the core engine to the fan case. Each support structure has two support struts which extend from the core engine to a joint radially outwardly of the fan case. The support struts are spaced apart at the core engine but converge to meet at the joint. Each support structure further has two structural elements which extend from the joint to respective fixing positions on the fan case at opposite sides of the joint.

Abstract: A guide 2 for a burr cutter 34, the guide 2 comprising: a body portion 4 having first and second guide surfaces 12a, 12b which are spaced from one another to define a slot 14 between the first and second guide surfaces 12a, 12b; a bearing 32a, 32b for rotatably mounting the body portion 4 to a shank 38 of the burr cutter 34 with a cutting head 36 of the burr cutter 34 adjacent the slot 14; wherein the first and second guide surfaces 12a, 12b and the bearing 32a, 32b are positioned relative to one another such that the first and second guide surfaces 12a, 12b are tangential to the cutting head 36 of the burr cutter 34.

Abstract: A fan casing for fitment around an array of radially extending fan blades of a gas turbine engine. The fan casing includes an annular casing element; and an annular fan track liner positioned radially inward of the annular casing element. The fan track liner includes an abradable layer and an abrasive layer, the abrasive layer being positioned radially inward of the abradable layer and proximal, in use, to the fan blades.

Abstract: A fan casing for fitment around an array of radially extending fan blades of a gas turbine engine. The fan casing includes an annular casing element; and an annular fan track liner positioned radially inward of the annular casing element. The fan track liner includes an abradable layer and an abrasive layer, the abrasive layer being positioned radially inward of the abradable layer and proximal, in use, to the fan blades.

Abstract: A ducted fan gas turbine engine has a propulsive fan, a fan case surrounding the fan, a core engine, and a plurality of support structures which transmit loads from the core engine to the fan case. Each support structure has two support struts which extend from the core engine to a joint radially outwardly of the fan case. The support struts are spaced apart at the core engine but converge to meet at the joint. Each support structure further has two structural elements which extend from the joint to respective fixing positions on the fan case at opposite sides of the joint.

Abstract: A method of reducing the fluid flow effects of one or more flow modifiers (19) in a passage (16), the method comprising: providing a plurality of aerofoil structures (15) in the passage (16), wherein the geometry of each aerofoil structure (15) is initially substantially the same; and shortening the trailing edge (18) of one or more selected aerofoil structures (17) in a chordwise direction and over at least a spanwise portion of the one or more selected aerofoil structures such that, when in use, the direction of the fluid flow (20a, 20e) in the vicinity of the one or more selected aerofoil structures is altered and the fluid flow effects of the one or more flow modifiers (19) in the passage are reduced.

Abstract: A seal assembly arranged adjacent to a primary flow region, the seal assembly including: first and second components; a seal arranged between the first and second components to seal a secondary flow region from the primary flow region; and a first recess portion provided in the first component and arranged adjacent to the seal and the primary flow region, the first recess portion further being arranged to receive flow from at least one of the primary flow region and the secondary flow region and shed flow to the primary flow region, wherein the first recess portion is configured to promote a first flow feature within the first recess portion, the first flow feature flowing with a portion of the first flow feature adjacent to the primary flow region and the portion of the first flow feature being shed to the primary flow region in substantially the same direction as the flow in the primary flow region.

Abstract: A method of reducing the fluid flow effects of one or more flow modifiers (19) in a passage (16), the method comprising: providing a plurality of aerofoil structures (15) in the passage (16), wherein the geometry of each aerofoil structure (15) is initially substantially the same; and shortening the trailing edge (18) of one or more selected aerofoil structures (17) in a chordwise direction and over at least a spanwise portion of the one or more selected aerofoil structures such that, when in use, the direction of the fluid flow (20a, 20e) in the vicinity of the one or more selected aerofoil structures is altered and the fluid flow effects of the one or more flow modifiers (19) in the passage are reduced.

Abstract: A seal assembly arranged adjacent to a primary flow region, the seal assembly including: first and second components; a seal arranged between the first and second components to seal a secondary flow region from the primary flow region; and a first recess portion provided in the first component and arranged adjacent to the seal and the primary flow region, the first recess portion further being arranged to receive flow from at least one of the primary flow region and the secondary flow region and shed flow to the primary flow region, wherein the first recess portion is configured to promote a first flow feature within the first recess portion, the first flow feature flowing with a portion of the first flow feature adjacent to the primary flow region and the portion of the first flow feature being shed to the primary flow region in substantially the same direction as the flow in the primary flow region.

Abstract: An acoustic panel for a fan casing of a gas turbine engine includes one or more Helmholtz resonators to absorb acoustic energy propagated upstream from the fan. By arranging that the periodic air flow out of the resonators has some axial momentum, by inclining the passages that exit from the necks of the resonators in a downstream direction, some of the energy in this air flow can be realised as a useful pressure rise in the direction of the air flow into the fan, rather than a pressure drop as in known acoustic panels.

Abstract: An acoustic panel for a fan casing of a gas turbine engine includes one or more Helmholtz resonators to absorb acoustic energy propagated upstream from the fan. By arranging that the periodic air flow out of the resonators has some axial momentum, by inclining the passages that from the necks of the resonators in a downstream direction, some of the energy in this air flow can be realised as a useful pressure rise in the direction of the air flow into the fan, rather than a pressure drop as in known acoustic panels.

Abstract: An aircraft engine comprising a nacelle, a first wall and fan outlet guide vanes. The fan outlet guide vanes comprises a plurality of stator vanes extending between a second wall and a third wall. The nacelle having apertures at a region of low pressure. A means to bleed fluid from a region of high pressure at one or more of the first wall, the second wall, the third wall or the stator vanes and at least one duct to connect the means to bleed fluid from the region of high pressure to the at least one aperture in the nacelle. The static pressure at the high pressure region is greater than that in the low pressure region such that at least some of the boundary layer of the fluid flows through the at least one duct to the at least one aperture in the nacelle.

Abstract: An aircraft (10) comprises a wing (12) having an upper surface (16) and a lower surface (18) and at least one turbofan gas turbine engine (20) mounted on the wing (12). The axis (34) of the at least one turbofan gas turbine engine (20) is arranged substantially in the plane (14) of the wing (12) of the aircraft (10). The at least one turbofan gas turbine engine (20) has an intake, the intake comprising a hollow member (44) rotatably mounted coaxially with the at least one turbofan gas turbine engine (20) such that in use the hollow member (44) is rotatable between a first position, a low-speed condition, in which air flowing over and/or above the upper surface (16) of the wing (12) flows into the intake of the at least one turbofan gas turbine engine (20) and a second position, a high-speed condition, in which air flowing along and/or below the lower surface (18) of the wing flows into the intake of the at least one turbofan gas turbine engine.

Abstract: An aircraft (10) comprises a wing (12) having an upper surface (16) and a lower surface (18) and at least one turbofan gas turbine engine (20) mounted on the wing (12). The axis (34) of the at least one turbofan gas turbine engine (20) is arranged substantially in the plane (14) of the wing (12) of the aircraft (10). The at least one turbofan gas turbine engine (20) has an intake, the intake comprising a hollow member (44) rotatably mounted coaxially with the at least one turbofan gas turbine engine (20) such that in use the hollow member (44) is rotatable between a first position, a low-speed condition, in which air flowing over and/or above the upper surface (16) of the wing (12) flows into the intake of the at least one turbofan gas turbine engine (20) and a second position, a high-speed condition, in which air flowing along and/or below the lower surface (18) of the wing flows into the intake of the at least one turbofan gas turbine engine.

Abstract: An aircraft (10) comprises a wing (12) having an upper surface (16) and a lower surface (18) and at least one turbofan gas turbine engine (20) mounted on the wing (12). The axis (34) of the at least one turbofan gas turbine engine (20) is arranged substantially in the plane (14) of the wing (12) of the aircraft (10). The at least one turbofan gas turbine engine (10) has an intake, the intake comprising a hollow member (44) rotatably mounted coaxially with the at least one turbofan gas turbine engine (20) such that in use the hollow member (44) is rotatable between a first position, a low-speed condition, in which air flowing over and/or above the upper surface (16) of the wing (12) flows into the intake of the at least one turbofan gas turbine engine (20) and a second position, a high-speed condition, in which air flowing along and/or below the lower surface (18) of the wing (12) flows into the intake of the at least one turbofan gas turbine engine (20).

Abstract: A fan (22) for a turbofan gas turbine engine (10) comprises a fan rotor (24) carrying a first set of circumferentially spaced radially extending fan blades (28) and a second set of circumferentially spaced radially extending fan blades (30). The second set of fan blades (30) is arranged downstream of the first set of fan blades (28). The hub to tip ratio (R1/R2) of the first set of fan blades (28) is substantially the same as the hub to tip ratio (R3/R4) of the second set of fan blades (30) and the radius (R2) of the radially outer ends of the first set of fan blades (28) is less than the radius (R4) of the radially outer ends of the second set of fan blades (30). This increases the flow area of the fan (22) by about 7% compared to a conventional fan of the same radius and thus increases the mass flow by about 7% and/or increases the pressure ratio.

Abstract: A fan (22) for a turbofan gas turbine engine (10) comprises a fan rotor (24) carrying a first set of circumferentially spaced radially extending fan blades (28) and a second set of circumferentially spaced radially extending fan blades (30). The second set of fan blades (30) is arranged downstream of the first set of fan blades (28). The hub to tip ratio (R1/R2) of the first set of fan blades (28) is substantially the same as the hub to tip ratio (R3/R4) of the second set of fan blades (30) and the radius (R2) of the radially outer ends of the first set of fan blades (28) is less than the radius (R4) of the radially outer ends of the second set of fan blades (30). This increases the flow area of the fan (22) by about 7% compared to a conventional fan of the same radius and thus increases the mass flow by about 7% and/or increases the pressure ratio.

Abstract: A nose cone assembly (30) for a gas turbine engine (10) comprising a spinner (34) having a generally conical forward portion (33) and a base portion (35). The base portion (35) of the spinner (34) is disposed radially inside an extended profile of the forward portion (33). Upon the base (35) there is a radially outwardly extending flange (41) through which mounting fasteners (40) are arranged to attach the spinner (34) to a fan hub (6) of the gas turbine engine (10). A fairing (36) is arranged to surround and cover the base portion (35) of the spinner (34) when the nose cone assembly (30) is fitted to the fan hub (6). The fairing (36) having a generally circumferentially and axially smooth continuous outer surface, the profile of which continues that of the forward portion 33 of the spinner 34. Fasteners (44) preferably extend from the fairing (36) in a substantially radially inwardly directed direction to attach the fairing (36).