US20180208297A1 - Nacelle for an aircraft aft fan - Google Patents
Nacelle for an aircraft aft fan Download PDFInfo
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- US20180208297A1 US20180208297A1 US15/411,228 US201715411228A US2018208297A1 US 20180208297 A1 US20180208297 A1 US 20180208297A1 US 201715411228 A US201715411228 A US 201715411228A US 2018208297 A1 US2018208297 A1 US 2018208297A1
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- nacelle
- aircraft
- forward section
- airflow duct
- airflow
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C7/00—Structures or fairings not otherwise provided for
- B64C7/02—Nacelles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
- B64C21/02—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like
- B64C21/06—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like for sucking
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
- B64C21/01—Boundary layer ingestion [BLI] propulsion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
- B64C21/02—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like
- B64C21/025—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like for simultaneous blowing and sucking
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
- B64D27/02—Aircraft characterised by the type or position of power plants
- B64D27/16—Aircraft characterised by the type or position of power plants of jet type
- B64D27/20—Aircraft characterised by the type or position of power plants of jet type within, or attached to, fuselages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
- B64D27/02—Aircraft characterised by the type or position of power plants
- B64D27/24—Aircraft characterised by the type or position of power plants using steam or spring force
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
- B64D27/02—Aircraft characterised by the type or position of power plants
- B64D27/30—Aircraft characterised by electric power plants
- B64D27/32—Aircraft characterised by electric power plants within, or attached to, fuselages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
- B64D27/02—Aircraft characterised by the type or position of power plants
- B64D27/30—Aircraft characterised by electric power plants
- B64D27/33—Hybrid electric aircraft
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D29/00—Power-plant nacelles, fairings, or cowlings
- B64D29/04—Power-plant nacelles, fairings, or cowlings associated with fuselages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D29/00—Power-plant nacelles, fairings, or cowlings
- B64D29/06—Attaching of nacelles, fairings or cowlings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C2230/00—Boundary layer controls
- B64C2230/04—Boundary layer controls by actively generating fluid flow
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C2230/00—Boundary layer controls
- B64C2230/06—Boundary layer controls by explicitly adjusting fluid flow, e.g. by using valves, variable aperture or slot areas, variable pump action or variable fluid pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C2230/00—Boundary layer controls
- B64C2230/20—Boundary layer controls by passively inducing fluid flow, e.g. by means of a pressure difference between both ends of a slot or duct
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
- B64D2033/0226—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes comprising boundary layer control means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
- B64D27/02—Aircraft characterised by the type or position of power plants
- B64D27/10—Aircraft characterised by the type or position of power plants of gas-turbine type
- B64D27/14—Aircraft characterised by the type or position of power plants of gas-turbine type within, or attached to, fuselages
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/10—Drag reduction
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the present subject matter relates generally to an aft engine for an aircraft propulsion system, and more particularly to a nacelle for the aft engine.
- a conventional commercial aircraft generally includes a fuselage, a pair of wings, and a propulsion system that provides thrust.
- the propulsion system typically includes at least two aircraft engines, such as turbofan jet engines.
- Each turbofan jet engine is mounted to a respective one of the wings of the aircraft, such as in a suspended position beneath the wing, separated from the wing and fuselage.
- Such a configuration allows for the turbofan jet engines to interact with separate, freestream airflows that are not impacted by the wings and/or fuselage. This configuration can reduce an amount of turbulence within the air entering an inlet of each respective turbofan jet engine, which has a positive effect on a net propulsive thrust of the aircraft.
- a drag on the aircraft including the turbofan jet engines also has an effect on the net propulsive thrust of the aircraft.
- a total amount of drag on the aircraft, including skin friction and form drag is generally proportional to a difference between a freestream velocity of air approaching the aircraft and an average velocity of a wake downstream from the aircraft that is produced due to the drag on the aircraft.
- Certain solutions to reducing an overall drag of an aircraft include positioning a fan at an aft end of the fuselage of the aircraft to re-energize a boundary layer airflow over the aft end of the fuselage. Accordingly, an aft fan configured to maximize an amount of relatively low momentum boundary layer air ingested would be useful.
- an aircraft defining a longitudinal direction includes a fuselage extending between a forward end and an aft end along the longitudinal direction of the aircraft.
- the aircraft additionally includes an aft engine mounted to the aft end of the fuselage, the aft engine further including a nacelle including a forward section.
- the aircraft additionally includes an airflow duct extending at least partially through the nacelle of the aft engine and including an opening on the forward section of the nacelle for providing an airflow to, or receiving an airflow from, the forward section of the nacelle.
- a propulsion system for an aircraft includes a fuselage defining an aft end.
- the propulsion system includes an aft engine configured to be mounted to the aft end of the fuselage.
- the aft engine includes a nacelle including a forward section.
- the propulsion system further includes an airflow duct extending at least partially through the nacelle of the aft engine and including an opening on the forward section of the nacelle for providing an airflow to, or receiving an airflow from, the forward section of the nacelle.
- FIG. 1 is a top view of an aircraft according to various exemplary embodiments of the present disclosure.
- FIG. 2 is a port side view of the exemplary aircraft of FIG. 1
- FIG. 3 is a schematic, cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure.
- FIG. 4 is a schematic, cross-sectional view of an aft engine in accordance with an exemplary embodiment of the present disclosure.
- FIG. 5 is a schematic, cross-sectional view of an aft engine in accordance with another exemplary embodiment of the present disclosure.
- FIG. 6 is a schematic, cross-sectional view of an aft engine in accordance with yet another exemplary embodiment of the present disclosure.
- FIG. 7 is a forward-looking-aft view of an aft engine in accordance with yet another exemplary embodiment of the present disclosure.
- FIG. 8 is a schematic, cross-sectional view of an aft engine in accordance with still another exemplary embodiment of the present disclosure.
- first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
- the terms “forward” and “aft” refer to the relative positions of a component based on an actual or anticipated direction of travel. For example, “forward” may refer to a front of an aircraft based on an anticipated direction of travel of the aircraft, and “aft” may refer to a back of the aircraft based on an anticipated direction of travel of the aircraft.
- upstream and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.
- the present disclosure is directed to a propulsion system and an aircraft including the same.
- the propulsion system generally includes an aft engine mounted to an aft end of a fuselage of the aircraft.
- the aft engine may ingest and re-energize boundary layer airflow over the aft end of the fuselage.
- the aft engine includes a nacelle extending around a fan having a plurality of fan blades.
- the nacelle includes a forward section having a lip. More particularly, the forward section of the nacelle includes a top portion having a top lip and a bottom portion having a bottom lip.
- An airflow duct is also provided extending at least partially through the nacelle and including an outlet on the lip of the forward section of the nacelle.
- the outlet provides an airflow to the lip of the forward section of the nacelle to urge an additional amount of boundary layer airflow over the aft end of the fuselage into the aft engine.
- a bottom side of the fuselage of the aft engine may have more, relatively low momentum airflow flowing thereover.
- a takeoff angle and other constraints may minimize an allowable size for the nacelle of the aft fan.
- the outlet of the airflow duct may be positioned on the bottom lip of the forward section of the nacelle to urge additional relatively low momentum airflow into the aft engine and/or guide air flow smoothly into the engine.
- FIG. 1 illustrates a top view of one embodiment of the aircraft 10 according to the present disclosure.
- FIG. 2 illustrates a port side view of the aircraft 10 as illustrated in FIG. 1 .
- the aircraft 10 defines a longitudinal centerline 14 that extends therethrough, a vertical direction V, a transverse direction T, and a longitudinal direction L.
- the aircraft 10 includes a fuselage 12 , extending longitudinally between a forward end 16 and an aft end 18 , and a pair of wings 20 .
- fuselage generally includes all of the body of the aircraft 10 , such as an empennage of the aircraft 10 and an outer surface or skin 38 of the aircraft 10 .
- the first of such wings 20 extends laterally outwardly with respect to the longitudinal centerline 14 from a port side 22 of the fuselage 12 and the second of such wings 20 extends laterally outwardly with respect to the longitudinal centerline 14 from a starboard side 24 of the fuselage 12 .
- each of the wings 20 depicted includes one or more leading edge flaps 26 and one or more trailing edge flaps 28 .
- the aircraft 10 may also include a vertical stabilizer 30 having a rudder flap 32 for yaw control, and a pair of horizontal stabilizers 34 , each having an elevator flap 36 for pitch control. It should be appreciated however, that in other exemplary embodiments of the present disclosure, the aircraft 10 may additionally or alternatively include any other suitable configuration of stabilizer that may or may not extend directly along the vertical direction V or horizontal/transverse direction T.
- the aircraft 10 of FIGS. 1 and 2 includes a propulsion system 100 , herein referred to as “system 100 .”
- the system 100 includes a pair of aircraft engines, at least one of which mounted to each of the pair of wings 20 , and an aft engine.
- the aircraft engines are configured as turbofan jet engines 102 , 104 suspended beneath the wings 20 in an under-wing configuration.
- the aft engine is configured as an engine that ingests and consumes air forming a boundary layer over the fuselage 12 of the aircraft 10 .
- the aft engine is configured as a fan, i.e., a Boundary Layer Ingestion (BLI) fan 106 , configured to ingest and consume air forming a boundary layer over the fuselage 12 of the aircraft 10 .
- BLI Boundary Layer Ingestion
- the BLI fan 106 is mounted to the aircraft 10 at a location aft of the wings 20 and/or the jet engines 102 , 104 , such that a central axis 15 extends therethrough.
- the “central axis” refers to a midpoint line extending along a length of the BLI fan 106 .
- the BLI fan 106 is fixedly connected to the fuselage 12 at the aft end 18 of the fuselage 12 , such that the BLI fan 106 is incorporated into or blended with a tail section at the aft end 18 .
- the jet engines 102 , 104 may be configured to provide power to an electric generator 108 and/or an energy storage device 110 .
- one or both of the jet engines 102 , 104 may be configured to provide mechanical power from a rotating shaft (such as an LP shaft or HP shaft) to the electric generator 108 .
- the electric generator 108 may be configured to convert the mechanical power to electrical power and provide such electrical power to one or more energy storage devices 110 and/or the BLI fan 106 .
- the propulsion system 100 may be referred to as a gas-electric propulsion system. It should be appreciated, however, that the aircraft 10 and propulsion system 100 depicted in FIGS. 1 and 2 is provided by way of example only and that in other exemplary embodiments of the present disclosure, any other suitable aircraft 10 may be provided having a propulsion system 100 configured in any other suitable manner.
- the jet engines 102 , 104 may be configured as high-bypass turbofan jet engines. More specifically, FIG. 3 illustrates a schematic cross-sectional view of one embodiment of a high-bypass turbofan jet engine 200 , herein referred to as “turbofan 200 .”
- the turbofan 200 may be representative of jet engines 102 , 104 .
- the turbofan 200 engine 10 defines an axial direction A 1 (extending parallel to a longitudinal centerline 201 provided for reference) and a radial direction R 1 .
- the turbofan 200 includes a fan section 202 and a core turbine engine 204 disposed downstream from the fan section 202 .
- the core turbine engine 204 generally includes a substantially tubular outer casing 206 that defines an annular inlet 208 .
- the outer casing 206 encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor 210 and a high pressure (HP) compressor 212 ; a combustion section 214 ; a turbine section including a high pressure (HP) turbine 216 and a low pressure (LP) turbine 218 ; and a jet exhaust nozzle section 220 .
- a high pressure (HP) shaft or spool 222 drivingly connects the HP turbine 216 to the HP compressor 212 .
- a low pressure (LP) shaft or spool 224 drivingly connects the LP turbine 218 to the LP compressor 210 .
- the fan section 202 includes a variable pitch fan 226 having a plurality of fan blades 228 coupled to a disk 230 in a spaced apart manner. As depicted, the fan blades 228 extend outwardly from the disk 230 generally along the radial direction R 1 . Each fan blade 228 is rotatable relative to the disk 230 about a pitch axis by virtue of the fan blades 228 being operatively coupled to a suitable actuation member 232 configured to collectively vary the pitch of the fan blades 228 , e.g., in unison.
- the fan blades 228 , the disk 230 , and the actuation member 232 are together rotatable about the longitudinal axis 12 by LP shaft 224 across, for the embodiment depicted, a power gearbox 234 .
- the power gearbox 234 includes a plurality of gears for stepping down the rotational speed of the LP shaft 224 to a more efficient rotational fan speed.
- the disk 230 is covered by rotatable front hub 236 aerodynamically contoured to promote an airflow through the plurality of fan blades 228 .
- the fan section 202 includes an annular fan casing or outer nacelle 238 that circumferentially surrounds the fan 226 and/or at least a portion of the core turbine engine 204 .
- the outer nacelle 238 is supported relative to the core turbine engine 204 by a plurality of circumferentially-spaced outlet guide vanes 240 .
- a downstream section 242 of the nacelle 238 extends over an outer portion of the core turbine engine 204 so as to define a bypass airflow passage 244 therebetween.
- turbofan engine 200 depicted in FIG. 3 is by way of example only, and that in other exemplary embodiments, the turbofan engine 200 may have any other suitable configuration. Further, it should be appreciated, that in other exemplary embodiments, the jet engines 102 , 104 may instead be configured as any other suitable aeronautical engine, such as a turbojet engine or turboprop engine.
- the aft engine is configured as a boundary layer ingestion (BLI) fan 300 mounted to an aft end 18 of a fuselage 12 of an aircraft 10 .
- the BLI fan 300 may be configured in substantially the same manner as the BLI fan 106 described above with reference to FIGS. 1 and 2 and the aircraft 10 may be configured in substantially the same manner as the exemplary aircraft 10 described above with reference to FIGS. 1 and 2 .
- the BLI fan 300 defines an axial direction A 2 extending along a centerline 301 of the BLI fan 300 , which for the embodiment depicted is the same as the central axis 15 . Additionally, the BLI fan 300 defines a radial direction R 2 and a circumferential direction C 2 (i.e., a direction extending about the axial direction A 2 ; see FIG. 7 ). In general, the BLI fan 300 includes a fan 304 rotatable about the centerline 301 , a nacelle 306 extending around at least a portion of the fan 304 , and one or more structural members extending between the nacelle 306 and the fuselage 12 of the aircraft 10 .
- the one or more structural members may be configured as one or more inlet guide vanes 308 and/or as one or more outlet guide vanes 324 .
- the term “fuselage” includes an inner surface of the BLI fan 300 even though in certain embodiments, the inner surface of the BLI fan 300 may be formed with the BLI fan 300 and mounted to, e.g., a bulkhead (not shown) within the fuselage 12 of the aircraft 10 as a unit.
- the fan 304 includes a plurality of fan blades 310 spaced generally along the circumferential direction C 2 .
- the inlet guide vanes 308 extend between the nacelle 306 and the fuselage 12 of the aircraft 10 at a location forward of the plurality of fan blades 310 . More specifically, as shown, the inlet guide vanes 308 generally extend substantially along the radial direction R 2 of the BLI fan 300 between the nacelle 306 and the fuselage 12 of the aircraft 10 for mounting the BLI fan 300 to the fuselage 12 of the aircraft 10 .
- the inlet guide vanes 308 may spaced substantially evenly along the circumferential direction C 2 of the BLI fan 300 , or in any other suitable manner.
- the inlet guide vanes 308 may be shaped and/or oriented to direct and/or condition a flow of air into the BLI fan 300 to, e.g., increase an efficiency of the BLI fan 300 , or reduce a distortion of the air flowing into the BLI fan 300 .
- the inlet guide vanes 308 may be configured as fixed inlet guide vanes extending between the nacelle 306 and the fuselage 12 of the aircraft 10 .
- the inlet guide vanes 308 may be configured as variable inlet guide vanes.
- the inlet guide vanes 308 include a body 320 and a tail flap 322 .
- the body 320 is fixed relative to the nacelle 306 of the BLI fan 300 and the flap 322 is configured to rotate about a substantially radial axis. By rotating the flap 322 between various positions, the inlet guide vanes 308 may be configured to vary a direction in which air flowing thereover is directed.
- the fan 304 additionally includes a fan shaft 312 with the plurality of fan blades 310 attached thereto.
- the fan shaft 312 may be rotatably supported by one or more bearings located forward of the plurality of fan blades 310 and, optionally, one or more bearings located aft of the plurality of fan blades 310 .
- Such bearings may be any suitable combination of roller bearings, ball bearings, thrust bearings, etc.
- the plurality of fan blades 310 may be attached in a fixed manner to the fan shaft 312 , or alternatively, the plurality of fan blades 310 may be rotatably attached to the fan shaft 312 .
- the plurality of fan blades 310 may be attached to the fan shaft 312 such that a pitch of each of the plurality of fan blades 310 may be changed, e.g., in unison, by a pitch change mechanism (not shown). Changing the pitch of the plurality of fan blades 310 may increase an efficiency of the BLI fan 300 and/or may allow the BLI fan 300 to achieve a desired thrust profile.
- the BLI fan 300 may be referred to as a variable pitch BLI fan.
- the fan shaft 312 is mechanically coupled to a power source 314 located at least partially within the fuselage 12 of the aircraft 10 , forward of the plurality of fan blades 310 . Further, for the embodiment depicted, the fan shaft 312 is mechanically coupled to the power source 314 through a gearbox 316 .
- the gearbox 316 may be configured to modify a rotational speed of the power source 314 , or rather of a shaft 315 of the power source 314 , such that the fan 304 of the BLI fan 300 rotates at a desired rotational speed.
- the gearbox 316 may be a fixed ratio gearbox, or alternatively, the gearbox 316 may define a variable gear ratio. With such an embodiment, the gearbox 316 may be operably connected to, e.g., a controller of the aircraft 10 for changing its ratio in response to one or more flight conditions.
- the BLI fan 300 may be configured with a gas-electric propulsion system, such as the gas-electric propulsion system 100 described above with reference to FIG. 1 .
- the power source 314 may be an electric motor that receives power from one or both of an energy storage device or an electric generator—such as the energy storage device 110 or electric generator 108 of FIGS. 1 and 2 , the electric generator 108 converting mechanical power received from one or more under-wing mounted aircraft engines to electric power.
- the BLI fan 300 may be an electric fan.
- the power source 314 may instead be any other suitable power source.
- the power source 314 may alternatively be configured as a gas engine, such as a gas turbine engine or internal combustion engine.
- the power source 314 may be positioned at any other suitable location within, e.g., the fuselage 12 of the aircraft 10 or the BLI fan 300 .
- the power source 314 may be configured as a gas turbine engine positioned at least partially within the BLI fan 300 .
- the BLI fan 300 may also additionally include one or more outlet guide vanes 324 and a tail cone 326 .
- the outlet guide vanes 324 extend between the nacelle 306 and the tail cone 326 for directing a flow of air through the BLI fan 300 , and optionally for adding strength and rigidity to the BLI fan 300 .
- the outlet guide vanes 324 may be evenly spaced along the circumferential direction C 2 or may have any other suitable spacing.
- the outlet guide vanes 324 may be fixed outlet guide vanes, or alternatively may be variable outlet guide vanes. Inclusion of the plurality of outlet guide vanes 324 extending between the nacelle 306 and the tail cone 326 may allow for, e.g., an efficiency of the BLI fan 300 may be maximized.
- the BLI fan 300 additionally defines a nozzle 328 between the nacelle 306 and the tail cone 326 .
- the nozzle 328 may be configured to generate an amount of thrust from the air flowing therethrough.
- the tail cone 326 may be shaped to minimize an amount of drag on the BLI fan 300 .
- the tail cone 326 may have any other shape and may, e.g., end forward of an aft end of the nacelle 306 such that the tail cone 326 is enclosed by the nacelle 306 at an aft end.
- the BLI fan 300 may not be configured to generate any significant amount of thrust, and instead may be configured to ingest air from a boundary layer of air of the fuselage 12 of the aircraft 10 and add energy/speed up such air to reduce an overall drag on the aircraft 10 (and thus increase a propulsive efficiency of the aircraft 10 ).
- the nacelle 306 extends around and encircles the plurality of fan blades 310 , and also extends around the fuselage 12 of the aircraft 10 at the aft end 18 of the fuselage 12 when, as shown in FIG. 4 , the BLI fan 300 is mounted to the fuselage 12 .
- the term “nacelle” includes the nacelle as well as any structural fan casing or housing.
- the nacelle 306 generally includes a forward section 330 having a lip (the “forward section 330 ” being a portion of the nacelle 306 forward of the plurality of fan blades 310 ).
- the forward section 330 of the nacelle 306 includes a top portion 332 and a bottom portion 334 .
- the top portion 332 includes a top lip 336 and the bottom portion 334 includes a bottom lip 338 .
- the top portion 332 may be a top half of the forward section 330 of the nacelle 306 and the bottom portion 334 may be a bottom half of the forward section 330 of the nacelle 306 .
- the bottom portion 334 may only be a bottom twenty-five percent (25%) of the forward section 330 of the nacelle 306 .
- lip such as the top lip 336 or bottom lip 338 , may refer to a forward twenty percent (20%) of the portion of the nacelle 306 , based on a total camber line length of the respective portion of the nacelle 306 .
- the bottom lip 338 of the forward section 330 of the nacelle 306 defines a baseline stagnation point 340 .
- the baseline stagnation point 340 refers to a point on the bottom lip 338 inward of which a boundary layer airflow 342 is ingested by the BLI fan 300 and outward of which the boundary layer airflow 342 passes over the nacelle 306 of the BLI fan 300 .
- “Inward”, as used herein, refers to relative position along the radial direction R 2 closer to the centerline 301 and “outward”, as used herein, refers to the relative position along the radial direction R 2 farther away from the centerline 301 .
- an airflow duct 344 is provided extending at least partially through the nacelle 306 and including an opening on the forward section 330 of the nacelle 306 for providing an airflow to the forward section 330 of the nacelle 306 . More specifically, for the exemplary embodiment depicted, the opening of the airflow duct 344 is an outlet 346 .
- the outlet 346 is positioned on the lip of the forward section 330 of the nacelle 306 and provides an airflow to the lip of the forward section 330 of the nacelle 306 to urge or guide boundary layer airflow 342 into the BLI fan 300 .
- the outlet 346 of the airflow duct 344 is positioned on the bottom lip 338 of the bottom portion 334 of the forward section 330 of the nacelle 306 .
- the outlet 346 is oriented inwardly along the radial direction R 2 in order to urge or guide an additional amount of boundary layer airflow 342 into the BLI fan 300 .
- the term “oriented inwardly along the radial direction”, with respect to the outlet 342 refers to a local portion of the airflow duct 344 immediately upstream of the outlet 342 defining a centerline pointed towards, or intersecting with, the centerline 301 of the BLI fan 300 .
- the outlet 346 is oriented in the same direction as the incoming boundary flow 342 (i.e., a local portion of the airflow duct 344 immediately upstream of the outlet 342 defining a centerline intersecting the centerline 301 at a location aft of the outlet 342 along the axial direction A 2 ). It should be appreciated, however, that in other exemplary embodiments, the outlet 346 may alternatively be oriented in a direction towards the incoming boundary flow 342 so as to reduce the level of inflow distortion seen by the BLI fan 300 (see embodiment of FIG. 5 , described below).
- the airflow duct 344 includes an inlet 348 and a body 350 .
- the nacelle 306 includes an outer surface 352 and the inlet 348 of the airflow duct 344 is positioned on the outer surface 352 of the nacelle 306 for receiving a flow of air, such as a flow of substantially higher pressure air relative to the boundary layer airflow 342 .
- the body 350 of the airflow duct 344 extends from the inlet 348 on the outer surface 352 of the nacelle 306 , to the outlet 346 on the bottom lip 338 of the forward section 330 of the nacelle 306 .
- the air received through the inlet 348 may flow through the body 350 to the outlet 346 , which as is stated is for the embodiment depicted oriented inwardly along the radial direction R 2 of the BLI fan 300 .
- Providing the air received through the inlet 348 which may be at a relatively high pressure relative to the boundary layer airflow 342 over the fuselage 12 of the aircraft 10 , to and through the outlet 346 of the airflow duct 344 may result in the airflow being guided more smoothly into the fan or an additional amount of boundary layer airflow 342 to be ingested by the BLI fan 300 .
- the aft engine, nacelle 306 of the aft engine, and airflow duct 344 may additionally or alternatively be configured in any other suitable manner.
- the opening on the forward section 330 of the nacelle 306 is instead configured for receiving an airflow from the forward section 330 of the nacelle 306 .
- the opening is not configured as the outlet 346 , and instead is configured as an inlet 347 such that an airflow is vented from within the nacelle 306 to an outlet 349 of the airflow duct 344 (e.g., to reduce a distortion perceived by the fan).
- FIG. 6 a close-up view of an airflow duct 344 in accordance with yet another exemplary embodiment of the present disclosure is provided, the airflow duct 344 extending at least partially through a nacelle 306 of an aft engine.
- the exemplary airflow duct 344 and aft engine depicted in FIG. 6 may be configured in substantially the same manner as exemplary airflow duct 344 and aft engine described above with reference to FIG. 4 . Accordingly, the same numbers may refer to the same or similar part.
- the aft engine may be configured as a BLI fan 300 , with the BLI fan 300 including a nacelle 306 encircling a fan 304 having a plurality of fan blades 310 .
- the nacelle 306 includes a forward section 330 having a lip, or more particularly, a forward section 330 defining a top portion 332 having a top lip 336 and a bottom portion 334 having a bottom lip 338 .
- an airflow duct 344 is provided having an inlet 348 and an outlet 346 , with a body 350 extending therebetween.
- the inlet 348 is not positioned on an outer surface 352 of the nacelle 306 , and instead the airflow duct 344 defines an inlet 348 on an inner surface 354 of the nacelle 306 . More specifically, the airflow duct 344 defines the inlet 348 on the inner surface 354 of the nacelle 306 downstream of the fan 304 , or rather downstream of the plurality of fan blades 310 of the fan 304 .
- Such a configuration may ensure an airflow through the airflow duct 344 , as the inlet 348 is positioned at a relatively high pressure area of the BLI fan 300 , such that the airflow duct 344 may receive pressurized air from the BLI fan 300 .
- the inlet 348 is defined on the inner surface 354 of the nacelle 306 immediately downstream of the plurality of fan blades 310 of the fan 304 , in other embodiments, the inlet 348 may be defined on the inner surface 354 of the nacelle 306 at a nozzle section 328 of the BLI fan 300 .
- the outlet 346 of the airflow duct 344 includes a plurality of outlets 346 .
- the plurality of outlets 346 includes at least one outlet 346 positioned outward of a baseline stagnation point 340 of the bottom portion 334 of the forward section 330 of the nacelle 306 , and at least one outlet 346 positioned inward of the baseline stagnation point 340 of the bottom portion 334 of the forward section 330 of the nacelle 306 .
- each of the plurality of outlets 346 are oriented inwardly along a radial direction R 2 of the BLI fan 300 .
- each of the plurality of outlets 346 are spaced along the radial direction R 2 of the BLI fan 300 for the embodiment depicted, in other embodiments, the plurality of outlets 346 may additionally, or alternatively, be spaced in any other suitable manner.
- FIG. 7 a forward-looking-aft view of a BLI fan 300 is provided in accordance with an exemplary aspect of the present disclosure.
- the exemplary BLI fan 300 of FIG. 7 may be configured in substantially the same manner as exemplary BLI fan 300 of FIG. 4 . Accordingly, the same numbers refer to the same or similar part.
- the exemplary BLI fan 300 includes an outer nacelle 306 that extends generally along a circumferential direction of the BLI fan 300 .
- a forward section 330 of the outer nacelle 306 is provided with a plurality of outlets 346 of an airflow duct 344 defined therein.
- the plurality of outlets 346 are, for the exemplary embodiment of FIG. 7 , spaced along a lip of the forward section 330 of the nacelle 306 .
- the plurality of outlets 346 are spaced along the circumferential direction C 2 of the BLI fan 300 , or more particularly, spaced along a bottom lip 338 of a bottom portion 334 of the forward section 330 of the nacelle 306 along the circumferential direction C 2 of the BLI fan 300 . It should be appreciated, however, that in other exemplary embodiments, the plurality of outlets 346 may additionally, or alternatively, be spaced along a top lip 336 of the top portion 332 of the nacelle 306 .
- the plurality of outlets 246 may be spaced substantially evenly along the circumferential direction C 2 .
- the plurality of outlets 346 may be spaced closer together proximate a bottom-most point of the bottom portion 334 of the forward section 330 . Such a configuration may maximize a benefit achieved by inclusion of the airflow duct 344 .
- each of the plurality of outlets 346 are substantially the same size.
- one or more of the plurality of outlets 246 may define any other suitable size relative to the rest of the plurality of outlets 246 .
- the airflow duct 344 may additionally be configured in any other suitable manner.
- the entirety of the airflow duct 344 is positioned within the nacelle 306
- the airflow duct 344 may instead extend through/be positioned within other components of the aft engine and/or aircraft 10 .
- FIG. 8 a close-up view of an airflow duct 344 in accordance with yet another exemplary embodiment of the present disclosure is provided, the airflow duct 344 extending at least partially through a nacelle 306 of an aft engine.
- the exemplary airflow duct 344 and aft engine depicted in FIG. 8 may be configured in substantially the same manner as exemplary airflow duct 344 and aft engine described above with reference to FIG. 4 . Accordingly, the same numbers may refer to the same or similar part.
- the aft engine may be configured as a BLI fan 300 , with the BLI fan 300 including a nacelle 306 and a plurality of structural members extending between the nacelle 306 and a fuselage 12 of an aircraft 10 to which the BLI fan 300 is mounted.
- the exemplary structural members depicted are configured generally as inlet guide vanes 308 .
- the nacelle 306 includes a forward section 330 having a lip, or more particularly, a forward section 330 defining a top portion 332 having a top lip 336 and a bottom portion 334 having a bottom lip 338 .
- an airflow duct 344 is provided having outlet 346 on the bottom lip 338 for providing an airflow to the bottom lip 338 .
- the airflow duct 344 does not define an inlet 348 positioned on the nacelle 306 , and instead is configured to receive an airflow from a location remote from the BLI fan 300 .
- the airflow duct 344 extends at least partially through the nacelle 306 , through one or more of the structural members, or rather through one or more of the inlet guide vanes 308 , and forward through the fuselage 12 of the aircraft 10 .
- the airflow duct 344 may be configured to receive pressurized air from, e.g., from one or more underwing mounted engines (e.g., from a compressor section of an underwing mounted engine; see FIG.
- the airflow duct 344 further includes a variable throughput valve 356 positioned at least partially within the airflow duct 344 , or rather at least partially within the body 350 of the airflow duct 344 , such that the pressurized air flowing therethrough may be regulated.
- the aft engine, nacelle 306 , and airflow duct 344 may have any other suitable configuration.
- the airflow duct 344 may additionally, or alternatively, include one or more outlets positioned on the top lip 336 of the top portion 334 of the forward section 330 of the nacelle 306 .
- the airflow duct 344 may include additional features not described or depicted herein.
- the airflow duct 344 may include one or more fans or other pressurization devices for pressurizing an airflow therethrough.
- an airflow duct 344 with an aft engine in accordance with one or more exemplary embodiments of the present disclosure may allow for an increased efficiency of the aft engine by guiding boundary layer airflow or urging additional relatively low momentum airflow 342 flowing over a bottom side of the fuselage 12 of an aircraft 10 into the aft engine. Such may contribute to an overall increase an efficiency of the aircraft 10 , resulting in, e.g., a lower overall fuel consumption.
- inclusion of an airflow duct 344 in accordance with one or more embodiments of the present disclosure may reduce a perceived distortion on the fan of the aft engine by, e.g., venting airflow from within the nacelle to, e.g., reduce a severity of a total pressure distortion pattern ingested by the fan.
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Abstract
Description
- The present subject matter relates generally to an aft engine for an aircraft propulsion system, and more particularly to a nacelle for the aft engine.
- A conventional commercial aircraft generally includes a fuselage, a pair of wings, and a propulsion system that provides thrust. The propulsion system typically includes at least two aircraft engines, such as turbofan jet engines. Each turbofan jet engine is mounted to a respective one of the wings of the aircraft, such as in a suspended position beneath the wing, separated from the wing and fuselage. Such a configuration allows for the turbofan jet engines to interact with separate, freestream airflows that are not impacted by the wings and/or fuselage. This configuration can reduce an amount of turbulence within the air entering an inlet of each respective turbofan jet engine, which has a positive effect on a net propulsive thrust of the aircraft.
- However, a drag on the aircraft including the turbofan jet engines, also has an effect on the net propulsive thrust of the aircraft. A total amount of drag on the aircraft, including skin friction and form drag, is generally proportional to a difference between a freestream velocity of air approaching the aircraft and an average velocity of a wake downstream from the aircraft that is produced due to the drag on the aircraft.
- Certain solutions to reducing an overall drag of an aircraft include positioning a fan at an aft end of the fuselage of the aircraft to re-energize a boundary layer airflow over the aft end of the fuselage. Accordingly, an aft fan configured to maximize an amount of relatively low momentum boundary layer air ingested would be useful.
- Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
- In one exemplary embodiment of the present disclosure, an aircraft defining a longitudinal direction is provided. The aircraft includes a fuselage extending between a forward end and an aft end along the longitudinal direction of the aircraft. The aircraft additionally includes an aft engine mounted to the aft end of the fuselage, the aft engine further including a nacelle including a forward section. The aircraft additionally includes an airflow duct extending at least partially through the nacelle of the aft engine and including an opening on the forward section of the nacelle for providing an airflow to, or receiving an airflow from, the forward section of the nacelle.
- In another exemplary embodiment of the present disclosure, a propulsion system for an aircraft is provided. The aircraft includes a fuselage defining an aft end. The propulsion system includes an aft engine configured to be mounted to the aft end of the fuselage. The aft engine includes a nacelle including a forward section. The propulsion system further includes an airflow duct extending at least partially through the nacelle of the aft engine and including an opening on the forward section of the nacelle for providing an airflow to, or receiving an airflow from, the forward section of the nacelle.
- These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
- A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
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FIG. 1 is a top view of an aircraft according to various exemplary embodiments of the present disclosure. -
FIG. 2 is a port side view of the exemplary aircraft ofFIG. 1 -
FIG. 3 is a schematic, cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. -
FIG. 4 is a schematic, cross-sectional view of an aft engine in accordance with an exemplary embodiment of the present disclosure. -
FIG. 5 is a schematic, cross-sectional view of an aft engine in accordance with another exemplary embodiment of the present disclosure. -
FIG. 6 is a schematic, cross-sectional view of an aft engine in accordance with yet another exemplary embodiment of the present disclosure. -
FIG. 7 is a forward-looking-aft view of an aft engine in accordance with yet another exemplary embodiment of the present disclosure. -
FIG. 8 is a schematic, cross-sectional view of an aft engine in accordance with still another exemplary embodiment of the present disclosure. - Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.
- As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “forward” and “aft” refer to the relative positions of a component based on an actual or anticipated direction of travel. For example, “forward” may refer to a front of an aircraft based on an anticipated direction of travel of the aircraft, and “aft” may refer to a back of the aircraft based on an anticipated direction of travel of the aircraft. Additionally, the terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.
- Generally, the present disclosure is directed to a propulsion system and an aircraft including the same. The propulsion system generally includes an aft engine mounted to an aft end of a fuselage of the aircraft. The aft engine may ingest and re-energize boundary layer airflow over the aft end of the fuselage. The aft engine includes a nacelle extending around a fan having a plurality of fan blades. The nacelle includes a forward section having a lip. More particularly, the forward section of the nacelle includes a top portion having a top lip and a bottom portion having a bottom lip. An airflow duct is also provided extending at least partially through the nacelle and including an outlet on the lip of the forward section of the nacelle. The outlet provides an airflow to the lip of the forward section of the nacelle to urge an additional amount of boundary layer airflow over the aft end of the fuselage into the aft engine. Notably, in at least certain embodiments, a bottom side of the fuselage of the aft engine may have more, relatively low momentum airflow flowing thereover. A takeoff angle and other constraints may minimize an allowable size for the nacelle of the aft fan. Accordingly, in order to capture more of the relatively low momentum airflow flowing over the bottom side of the fuselage of the aircraft, the outlet of the airflow duct may be positioned on the bottom lip of the forward section of the nacelle to urge additional relatively low momentum airflow into the aft engine and/or guide air flow smoothly into the engine.
- Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,
FIG. 1 illustrates a top view of one embodiment of theaircraft 10 according to the present disclosure.FIG. 2 illustrates a port side view of theaircraft 10 as illustrated inFIG. 1 . As shown inFIGS. 1 and 2 collectively, theaircraft 10 defines alongitudinal centerline 14 that extends therethrough, a vertical direction V, a transverse direction T, and a longitudinal direction L. - Moreover, the
aircraft 10 includes afuselage 12, extending longitudinally between aforward end 16 and anaft end 18, and a pair ofwings 20. As used herein, the term “fuselage” generally includes all of the body of theaircraft 10, such as an empennage of theaircraft 10 and an outer surface orskin 38 of theaircraft 10. The first ofsuch wings 20 extends laterally outwardly with respect to thelongitudinal centerline 14 from aport side 22 of thefuselage 12 and the second ofsuch wings 20 extends laterally outwardly with respect to thelongitudinal centerline 14 from astarboard side 24 of thefuselage 12. Further, as shown in the illustrated embodiment, each of thewings 20 depicted includes one or more leadingedge flaps 26 and one or moretrailing edge flaps 28. Theaircraft 10 may also include avertical stabilizer 30 having arudder flap 32 for yaw control, and a pair ofhorizontal stabilizers 34, each having anelevator flap 36 for pitch control. It should be appreciated however, that in other exemplary embodiments of the present disclosure, theaircraft 10 may additionally or alternatively include any other suitable configuration of stabilizer that may or may not extend directly along the vertical direction V or horizontal/transverse direction T. - In addition, the
aircraft 10 ofFIGS. 1 and 2 includes apropulsion system 100, herein referred to as “system 100.” Thesystem 100 includes a pair of aircraft engines, at least one of which mounted to each of the pair ofwings 20, and an aft engine. For example, as shown, the aircraft engines are configured asturbofan jet engines wings 20 in an under-wing configuration. Additionally, the aft engine is configured as an engine that ingests and consumes air forming a boundary layer over thefuselage 12 of theaircraft 10. Specifically, the aft engine is configured as a fan, i.e., a Boundary Layer Ingestion (BLI)fan 106, configured to ingest and consume air forming a boundary layer over thefuselage 12 of theaircraft 10. Further, as shown inFIG. 2 , theBLI fan 106 is mounted to theaircraft 10 at a location aft of thewings 20 and/or thejet engines central axis 15 extends therethrough. As used herein, the “central axis” refers to a midpoint line extending along a length of theBLI fan 106. Further, for the illustrated embodiment, theBLI fan 106 is fixedly connected to thefuselage 12 at theaft end 18 of thefuselage 12, such that theBLI fan 106 is incorporated into or blended with a tail section at theaft end 18. - In various embodiments, the
jet engines electric generator 108 and/or anenergy storage device 110. For example, one or both of thejet engines electric generator 108. Additionally, theelectric generator 108 may be configured to convert the mechanical power to electrical power and provide such electrical power to one or moreenergy storage devices 110 and/or theBLI fan 106. Accordingly, in such embodiments, thepropulsion system 100 may be referred to as a gas-electric propulsion system. It should be appreciated, however, that theaircraft 10 andpropulsion system 100 depicted inFIGS. 1 and 2 is provided by way of example only and that in other exemplary embodiments of the present disclosure, any othersuitable aircraft 10 may be provided having apropulsion system 100 configured in any other suitable manner. - Referring now to
FIG. 3 , in certain embodiments, thejet engines FIG. 3 illustrates a schematic cross-sectional view of one embodiment of a high-bypassturbofan jet engine 200, herein referred to as “turbofan 200.” In various embodiments, theturbofan 200 may be representative ofjet engines turbofan 200engine 10 defines an axial direction A1 (extending parallel to alongitudinal centerline 201 provided for reference) and a radial direction R1. In general, theturbofan 200 includes afan section 202 and a core turbine engine 204 disposed downstream from thefan section 202. - In particular embodiments, the core turbine engine 204 generally includes a substantially tubular
outer casing 206 that defines anannular inlet 208. It should be appreciated, that as used herein, terms of approximation, such as “approximately,” “generally,” “substantially,” or “about,” refer to being within a ten percent margin of error. Theouter casing 206 encases, in serial flow relationship, a compressor section including a booster or low pressure (LP)compressor 210 and a high pressure (HP)compressor 212; acombustion section 214; a turbine section including a high pressure (HP)turbine 216 and a low pressure (LP)turbine 218; and a jetexhaust nozzle section 220. A high pressure (HP) shaft orspool 222 drivingly connects theHP turbine 216 to theHP compressor 212. A low pressure (LP) shaft orspool 224 drivingly connects theLP turbine 218 to theLP compressor 210. - Further, as shown, the
fan section 202 includes avariable pitch fan 226 having a plurality offan blades 228 coupled to adisk 230 in a spaced apart manner. As depicted, thefan blades 228 extend outwardly from thedisk 230 generally along the radial direction R1. Eachfan blade 228 is rotatable relative to thedisk 230 about a pitch axis by virtue of thefan blades 228 being operatively coupled to asuitable actuation member 232 configured to collectively vary the pitch of thefan blades 228, e.g., in unison. As such, thefan blades 228, thedisk 230, and theactuation member 232 are together rotatable about thelongitudinal axis 12 byLP shaft 224 across, for the embodiment depicted, apower gearbox 234. In certain embodiments, thepower gearbox 234 includes a plurality of gears for stepping down the rotational speed of theLP shaft 224 to a more efficient rotational fan speed. - Referring still to
FIG. 3 , thedisk 230 is covered by rotatablefront hub 236 aerodynamically contoured to promote an airflow through the plurality offan blades 228. Additionally, thefan section 202 includes an annular fan casing orouter nacelle 238 that circumferentially surrounds thefan 226 and/or at least a portion of the core turbine engine 204. Theouter nacelle 238 is supported relative to the core turbine engine 204 by a plurality of circumferentially-spaced outlet guide vanes 240. Moreover, adownstream section 242 of thenacelle 238 extends over an outer portion of the core turbine engine 204 so as to define abypass airflow passage 244 therebetween. - It should be appreciated, however, that the
turbofan engine 200 depicted inFIG. 3 is by way of example only, and that in other exemplary embodiments, theturbofan engine 200 may have any other suitable configuration. Further, it should be appreciated, that in other exemplary embodiments, thejet engines - Referring now to
FIG. 4 , a schematic, cross-sectional side view of an aft engine in accordance with various embodiments of the present disclosure is provided. More specifically, as shown, the aft engine is configured as a boundary layer ingestion (BLI)fan 300 mounted to anaft end 18 of afuselage 12 of anaircraft 10. TheBLI fan 300 may be configured in substantially the same manner as theBLI fan 106 described above with reference toFIGS. 1 and 2 and theaircraft 10 may be configured in substantially the same manner as theexemplary aircraft 10 described above with reference toFIGS. 1 and 2 . - More specifically, as shown, the
BLI fan 300 defines an axial direction A2 extending along acenterline 301 of theBLI fan 300, which for the embodiment depicted is the same as thecentral axis 15. Additionally, theBLI fan 300 defines a radial direction R2 and a circumferential direction C2 (i.e., a direction extending about the axial direction A2; seeFIG. 7 ). In general, theBLI fan 300 includes afan 304 rotatable about thecenterline 301, anacelle 306 extending around at least a portion of thefan 304, and one or more structural members extending between thenacelle 306 and thefuselage 12 of theaircraft 10. In certain embodiments, the one or more structural members may be configured as one or more inlet guidevanes 308 and/or as one or more outlet guide vanes 324. Notably, as used herein, the term “fuselage” includes an inner surface of theBLI fan 300 even though in certain embodiments, the inner surface of theBLI fan 300 may be formed with theBLI fan 300 and mounted to, e.g., a bulkhead (not shown) within thefuselage 12 of theaircraft 10 as a unit. - Further, the
fan 304 includes a plurality offan blades 310 spaced generally along the circumferential direction C2. Moreover, where present, theinlet guide vanes 308 extend between thenacelle 306 and thefuselage 12 of theaircraft 10 at a location forward of the plurality offan blades 310. More specifically, as shown, theinlet guide vanes 308 generally extend substantially along the radial direction R2 of theBLI fan 300 between thenacelle 306 and thefuselage 12 of theaircraft 10 for mounting theBLI fan 300 to thefuselage 12 of theaircraft 10. In addition, theinlet guide vanes 308 may spaced substantially evenly along the circumferential direction C2 of theBLI fan 300, or in any other suitable manner. - Further, the
inlet guide vanes 308 may be shaped and/or oriented to direct and/or condition a flow of air into theBLI fan 300 to, e.g., increase an efficiency of theBLI fan 300, or reduce a distortion of the air flowing into theBLI fan 300. In addition, it should be understood that theinlet guide vanes 308 may be configured as fixed inlet guide vanes extending between thenacelle 306 and thefuselage 12 of theaircraft 10. Alternatively, theinlet guide vanes 308 may be configured as variable inlet guide vanes. For example, as shown inFIG. 4 , theinlet guide vanes 308 include abody 320 and atail flap 322. Thebody 320 is fixed relative to thenacelle 306 of theBLI fan 300 and theflap 322 is configured to rotate about a substantially radial axis. By rotating theflap 322 between various positions, theinlet guide vanes 308 may be configured to vary a direction in which air flowing thereover is directed. - As is also depicted in
FIG. 4 , thefan 304 additionally includes afan shaft 312 with the plurality offan blades 310 attached thereto. Although not depicted, thefan shaft 312 may be rotatably supported by one or more bearings located forward of the plurality offan blades 310 and, optionally, one or more bearings located aft of the plurality offan blades 310. Such bearings may be any suitable combination of roller bearings, ball bearings, thrust bearings, etc. - In certain embodiments, the plurality of
fan blades 310 may be attached in a fixed manner to thefan shaft 312, or alternatively, the plurality offan blades 310 may be rotatably attached to thefan shaft 312. For example, the plurality offan blades 310 may be attached to thefan shaft 312 such that a pitch of each of the plurality offan blades 310 may be changed, e.g., in unison, by a pitch change mechanism (not shown). Changing the pitch of the plurality offan blades 310 may increase an efficiency of theBLI fan 300 and/or may allow theBLI fan 300 to achieve a desired thrust profile. With such an embodiment, theBLI fan 300 may be referred to as a variable pitch BLI fan. - The
fan shaft 312 is mechanically coupled to apower source 314 located at least partially within thefuselage 12 of theaircraft 10, forward of the plurality offan blades 310. Further, for the embodiment depicted, thefan shaft 312 is mechanically coupled to thepower source 314 through agearbox 316. Thegearbox 316 may be configured to modify a rotational speed of thepower source 314, or rather of ashaft 315 of thepower source 314, such that thefan 304 of theBLI fan 300 rotates at a desired rotational speed. Thegearbox 316 may be a fixed ratio gearbox, or alternatively, thegearbox 316 may define a variable gear ratio. With such an embodiment, thegearbox 316 may be operably connected to, e.g., a controller of theaircraft 10 for changing its ratio in response to one or more flight conditions. - In certain embodiments, the
BLI fan 300 may be configured with a gas-electric propulsion system, such as the gas-electric propulsion system 100 described above with reference toFIG. 1 . In such an embodiment, thepower source 314 may be an electric motor that receives power from one or both of an energy storage device or an electric generator—such as theenergy storage device 110 orelectric generator 108 ofFIGS. 1 and 2 , theelectric generator 108 converting mechanical power received from one or more under-wing mounted aircraft engines to electric power. Accordingly, in certain embodiments, theBLI fan 300 may be an electric fan. However, in other embodiments, thepower source 314 may instead be any other suitable power source. For example, thepower source 314 may alternatively be configured as a gas engine, such as a gas turbine engine or internal combustion engine. Moreover, in certain exemplary embodiments, thepower source 314 may be positioned at any other suitable location within, e.g., thefuselage 12 of theaircraft 10 or theBLI fan 300. For example, in certain embodiments, thepower source 314 may be configured as a gas turbine engine positioned at least partially within theBLI fan 300. - Referring still to
FIG. 4 , theBLI fan 300 may also additionally include one or more outlet guidevanes 324 and atail cone 326. As shown in the illustrated embodiment, theoutlet guide vanes 324 extend between thenacelle 306 and thetail cone 326 for directing a flow of air through theBLI fan 300, and optionally for adding strength and rigidity to theBLI fan 300. Further, theoutlet guide vanes 324 may be evenly spaced along the circumferential direction C2 or may have any other suitable spacing. Additionally, theoutlet guide vanes 324 may be fixed outlet guide vanes, or alternatively may be variable outlet guide vanes. Inclusion of the plurality ofoutlet guide vanes 324 extending between thenacelle 306 and thetail cone 326 may allow for, e.g., an efficiency of theBLI fan 300 may be maximized. - Further, aft of the plurality of
fan blades 310, and for the embodiment depicted, aft of the one or more outlet guidevanes 324, theBLI fan 300 additionally defines anozzle 328 between thenacelle 306 and thetail cone 326. As such, thenozzle 328 may be configured to generate an amount of thrust from the air flowing therethrough. In addition, thetail cone 326 may be shaped to minimize an amount of drag on theBLI fan 300. However, in other embodiments, thetail cone 326 may have any other shape and may, e.g., end forward of an aft end of thenacelle 306 such that thetail cone 326 is enclosed by thenacelle 306 at an aft end. Additionally, in other embodiments, theBLI fan 300 may not be configured to generate any significant amount of thrust, and instead may be configured to ingest air from a boundary layer of air of thefuselage 12 of theaircraft 10 and add energy/speed up such air to reduce an overall drag on the aircraft 10 (and thus increase a propulsive efficiency of the aircraft 10). - Referring still to
FIG. 4 , thenacelle 306 extends around and encircles the plurality offan blades 310, and also extends around thefuselage 12 of theaircraft 10 at theaft end 18 of thefuselage 12 when, as shown inFIG. 4 , theBLI fan 300 is mounted to thefuselage 12. Notably, as used herein, the term “nacelle” includes the nacelle as well as any structural fan casing or housing. Thenacelle 306 generally includes aforward section 330 having a lip (the “forward section 330” being a portion of thenacelle 306 forward of the plurality of fan blades 310). More specifically, theforward section 330 of thenacelle 306 includes atop portion 332 and abottom portion 334. Thetop portion 332 includes atop lip 336 and thebottom portion 334 includes abottom lip 338. Notably, in certain embodiments, thetop portion 332 may be a top half of theforward section 330 of thenacelle 306 and thebottom portion 334 may be a bottom half of theforward section 330 of thenacelle 306. However, in other embodiments, thebottom portion 334 may only be a bottom twenty-five percent (25%) of theforward section 330 of thenacelle 306. Additionally, as used herein, the term “lip”, such as thetop lip 336 orbottom lip 338, may refer to a forward twenty percent (20%) of the portion of thenacelle 306, based on a total camber line length of the respective portion of thenacelle 306. - As will be appreciated, the
bottom lip 338 of theforward section 330 of thenacelle 306 defines abaseline stagnation point 340. Thebaseline stagnation point 340 refers to a point on thebottom lip 338 inward of which aboundary layer airflow 342 is ingested by theBLI fan 300 and outward of which theboundary layer airflow 342 passes over thenacelle 306 of theBLI fan 300. “Inward”, as used herein, refers to relative position along the radial direction R2 closer to thecenterline 301 and “outward”, as used herein, refers to the relative position along the radial direction R2 farther away from thecenterline 301. In order to increase an amount of airflow and more smoothly guide theboundary layer airflow 342 ingested by theBLI fan 300, anairflow duct 344 is provided extending at least partially through thenacelle 306 and including an opening on theforward section 330 of thenacelle 306 for providing an airflow to theforward section 330 of thenacelle 306. More specifically, for the exemplary embodiment depicted, the opening of theairflow duct 344 is anoutlet 346. Theoutlet 346 is positioned on the lip of theforward section 330 of thenacelle 306 and provides an airflow to the lip of theforward section 330 of thenacelle 306 to urge or guideboundary layer airflow 342 into theBLI fan 300. More specifically, for the embodiment depicted, theoutlet 346 of theairflow duct 344 is positioned on thebottom lip 338 of thebottom portion 334 of theforward section 330 of thenacelle 306. As will be discussed in greater detail below, theoutlet 346 is oriented inwardly along the radial direction R2 in order to urge or guide an additional amount ofboundary layer airflow 342 into theBLI fan 300. Notably, as used herein, the term “oriented inwardly along the radial direction”, with respect to theoutlet 342, refers to a local portion of theairflow duct 344 immediately upstream of theoutlet 342 defining a centerline pointed towards, or intersecting with, thecenterline 301 of theBLI fan 300. Additionally, for the embodiment depicted, theoutlet 346 is oriented in the same direction as the incoming boundary flow 342 (i.e., a local portion of theairflow duct 344 immediately upstream of theoutlet 342 defining a centerline intersecting thecenterline 301 at a location aft of theoutlet 342 along the axial direction A2). It should be appreciated, however, that in other exemplary embodiments, theoutlet 346 may alternatively be oriented in a direction towards theincoming boundary flow 342 so as to reduce the level of inflow distortion seen by the BLI fan 300 (see embodiment ofFIG. 5 , described below). - Additionally, the
airflow duct 344 includes aninlet 348 and abody 350. As is depicted, thenacelle 306 includes anouter surface 352 and theinlet 348 of theairflow duct 344 is positioned on theouter surface 352 of thenacelle 306 for receiving a flow of air, such as a flow of substantially higher pressure air relative to theboundary layer airflow 342. For the embodiment depicted, thebody 350 of theairflow duct 344 extends from theinlet 348 on theouter surface 352 of thenacelle 306, to theoutlet 346 on thebottom lip 338 of theforward section 330 of thenacelle 306. The air received through theinlet 348 may flow through thebody 350 to theoutlet 346, which as is stated is for the embodiment depicted oriented inwardly along the radial direction R2 of theBLI fan 300. Providing the air received through theinlet 348, which may be at a relatively high pressure relative to theboundary layer airflow 342 over thefuselage 12 of theaircraft 10, to and through theoutlet 346 of theairflow duct 344 may result in the airflow being guided more smoothly into the fan or an additional amount ofboundary layer airflow 342 to be ingested by theBLI fan 300. - It should be appreciated, however, that in other embodiments, the aft engine,
nacelle 306 of the aft engine, andairflow duct 344 may additionally or alternatively be configured in any other suitable manner. For example, referring now briefly toFIG. 5 , providing a close-up view of anairflow duct 344 in accordance with another exemplary embodiment of the present disclosure, the opening on theforward section 330 of thenacelle 306 is instead configured for receiving an airflow from theforward section 330 of thenacelle 306. With such a configuration, the opening is not configured as theoutlet 346, and instead is configured as aninlet 347 such that an airflow is vented from within thenacelle 306 to anoutlet 349 of the airflow duct 344 (e.g., to reduce a distortion perceived by the fan). Additionally, referring now toFIG. 6 , a close-up view of anairflow duct 344 in accordance with yet another exemplary embodiment of the present disclosure is provided, theairflow duct 344 extending at least partially through anacelle 306 of an aft engine. Theexemplary airflow duct 344 and aft engine depicted inFIG. 6 may be configured in substantially the same manner asexemplary airflow duct 344 and aft engine described above with reference toFIG. 4 . Accordingly, the same numbers may refer to the same or similar part. - As is depicted, the aft engine may be configured as a
BLI fan 300, with theBLI fan 300 including anacelle 306 encircling afan 304 having a plurality offan blades 310. Thenacelle 306 includes aforward section 330 having a lip, or more particularly, aforward section 330 defining atop portion 332 having atop lip 336 and abottom portion 334 having abottom lip 338. Additionally, anairflow duct 344 is provided having aninlet 348 and anoutlet 346, with abody 350 extending therebetween. However, for the embodiment depicted, theinlet 348 is not positioned on anouter surface 352 of thenacelle 306, and instead theairflow duct 344 defines aninlet 348 on aninner surface 354 of thenacelle 306. More specifically, theairflow duct 344 defines theinlet 348 on theinner surface 354 of thenacelle 306 downstream of thefan 304, or rather downstream of the plurality offan blades 310 of thefan 304. Such a configuration may ensure an airflow through theairflow duct 344, as theinlet 348 is positioned at a relatively high pressure area of theBLI fan 300, such that theairflow duct 344 may receive pressurized air from theBLI fan 300. Notably, although for the embodiment depicted theinlet 348 is defined on theinner surface 354 of thenacelle 306 immediately downstream of the plurality offan blades 310 of thefan 304, in other embodiments, theinlet 348 may be defined on theinner surface 354 of thenacelle 306 at anozzle section 328 of theBLI fan 300. - Moreover, as is also depicted, for the embodiment depicted, the
outlet 346 of theairflow duct 344 includes a plurality ofoutlets 346. The plurality ofoutlets 346 includes at least oneoutlet 346 positioned outward of abaseline stagnation point 340 of thebottom portion 334 of theforward section 330 of thenacelle 306, and at least oneoutlet 346 positioned inward of thebaseline stagnation point 340 of thebottom portion 334 of theforward section 330 of thenacelle 306. For the embodiment depicted, each of the plurality ofoutlets 346 are oriented inwardly along a radial direction R2 of theBLI fan 300. - It should be appreciated, however, that although each of the plurality of
outlets 346 are spaced along the radial direction R2 of theBLI fan 300 for the embodiment depicted, in other embodiments, the plurality ofoutlets 346 may additionally, or alternatively, be spaced in any other suitable manner. For example, referring now toFIG. 7 , a forward-looking-aft view of aBLI fan 300 is provided in accordance with an exemplary aspect of the present disclosure. Theexemplary BLI fan 300 ofFIG. 7 may be configured in substantially the same manner asexemplary BLI fan 300 ofFIG. 4 . Accordingly, the same numbers refer to the same or similar part. Theexemplary BLI fan 300 includes anouter nacelle 306 that extends generally along a circumferential direction of theBLI fan 300. Aforward section 330 of theouter nacelle 306 is provided with a plurality ofoutlets 346 of anairflow duct 344 defined therein. As is depicted, the plurality ofoutlets 346 are, for the exemplary embodiment ofFIG. 7 , spaced along a lip of theforward section 330 of thenacelle 306. More specifically, for the embodiment depicted, the plurality ofoutlets 346 are spaced along the circumferential direction C2 of theBLI fan 300, or more particularly, spaced along abottom lip 338 of abottom portion 334 of theforward section 330 of thenacelle 306 along the circumferential direction C2 of theBLI fan 300. It should be appreciated, however, that in other exemplary embodiments, the plurality ofoutlets 346 may additionally, or alternatively, be spaced along atop lip 336 of thetop portion 332 of thenacelle 306. - In certain embodiments, the plurality of outlets 246 may be spaced substantially evenly along the circumferential direction C2. Alternatively, as in the embodiment depicted, the plurality of
outlets 346 may be spaced closer together proximate a bottom-most point of thebottom portion 334 of theforward section 330. Such a configuration may maximize a benefit achieved by inclusion of theairflow duct 344. Additionally, for the embodiment depicted, each of the plurality ofoutlets 346 are substantially the same size. However, in other embodiments, one or more of the plurality of outlets 246 may define any other suitable size relative to the rest of the plurality of outlets 246. - Moreover, it should be appreciated, that in other embodiments, the
airflow duct 344 may additionally be configured in any other suitable manner. For example, although for the exemplary embodiments described above, the entirety of theairflow duct 344 is positioned within thenacelle 306, in other embodiments, theairflow duct 344 may instead extend through/be positioned within other components of the aft engine and/oraircraft 10. For example, referring now toFIG. 8 , a close-up view of anairflow duct 344 in accordance with yet another exemplary embodiment of the present disclosure is provided, theairflow duct 344 extending at least partially through anacelle 306 of an aft engine. Theexemplary airflow duct 344 and aft engine depicted inFIG. 8 may be configured in substantially the same manner asexemplary airflow duct 344 and aft engine described above with reference toFIG. 4 . Accordingly, the same numbers may refer to the same or similar part. - As is depicted, the aft engine may be configured as a
BLI fan 300, with theBLI fan 300 including anacelle 306 and a plurality of structural members extending between thenacelle 306 and afuselage 12 of anaircraft 10 to which theBLI fan 300 is mounted. The exemplary structural members depicted are configured generally as inlet guide vanes 308. Thenacelle 306 includes aforward section 330 having a lip, or more particularly, aforward section 330 defining atop portion 332 having atop lip 336 and abottom portion 334 having abottom lip 338. Additionally, anairflow duct 344 is provided havingoutlet 346 on thebottom lip 338 for providing an airflow to thebottom lip 338. However, for the embodiment depicted, theairflow duct 344 does not define aninlet 348 positioned on thenacelle 306, and instead is configured to receive an airflow from a location remote from theBLI fan 300. Specifically, for the embodiment depicted, theairflow duct 344 extends at least partially through thenacelle 306, through one or more of the structural members, or rather through one or more of theinlet guide vanes 308, and forward through thefuselage 12 of theaircraft 10. With such an exemplary embodiment, theairflow duct 344 may be configured to receive pressurized air from, e.g., from one or more underwing mounted engines (e.g., from a compressor section of an underwing mounted engine; seeFIG. 3 ), or from any other suitable pressurized air source. With such an exemplary embodiment, theairflow duct 344 further includes avariable throughput valve 356 positioned at least partially within theairflow duct 344, or rather at least partially within thebody 350 of theairflow duct 344, such that the pressurized air flowing therethrough may be regulated. - It should be appreciated, however, that in other exemplary embodiments, the aft engine,
nacelle 306, andairflow duct 344 may have any other suitable configuration. For example, in other exemplary embodiments, theairflow duct 344 may additionally, or alternatively, include one or more outlets positioned on thetop lip 336 of thetop portion 334 of theforward section 330 of thenacelle 306. Moreover, in still other embodiments, theairflow duct 344 may include additional features not described or depicted herein. For example, in other embodiments, theairflow duct 344 may include one or more fans or other pressurization devices for pressurizing an airflow therethrough. - Inclusion of an
airflow duct 344 with an aft engine in accordance with one or more exemplary embodiments of the present disclosure may allow for an increased efficiency of the aft engine by guiding boundary layer airflow or urging additional relativelylow momentum airflow 342 flowing over a bottom side of thefuselage 12 of anaircraft 10 into the aft engine. Such may contribute to an overall increase an efficiency of theaircraft 10, resulting in, e.g., a lower overall fuel consumption. Additionally, or alternatively, inclusion of anairflow duct 344 in accordance with one or more embodiments of the present disclosure may reduce a perceived distortion on the fan of the aft engine by, e.g., venting airflow from within the nacelle to, e.g., reduce a severity of a total pressure distortion pattern ingested by the fan. - This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (20)
Priority Applications (5)
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US15/411,228 US20180208297A1 (en) | 2017-01-20 | 2017-01-20 | Nacelle for an aircraft aft fan |
EP23207884.0A EP4292939A3 (en) | 2017-01-20 | 2018-01-10 | Nacelle for an aircraft aft fan |
EP18151056.1A EP3351475B1 (en) | 2017-01-20 | 2018-01-10 | Nacelle for an aircraft aft fan |
CN201810053042.XA CN108327915A (en) | 2017-01-20 | 2018-01-19 | Cabin for aircraft rear fan |
US16/987,934 US11518499B2 (en) | 2016-09-30 | 2020-08-07 | Nacelle for an aircraft aft fan |
Applications Claiming Priority (1)
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US15/411,228 US20180208297A1 (en) | 2017-01-20 | 2017-01-20 | Nacelle for an aircraft aft fan |
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US15/281,990 Continuation-In-Part US10501196B2 (en) | 2016-09-30 | 2016-09-30 | Nacelle for an aircraft aft fan |
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US16/987,934 Division US11518499B2 (en) | 2016-09-30 | 2020-08-07 | Nacelle for an aircraft aft fan |
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US20180208297A1 true US20180208297A1 (en) | 2018-07-26 |
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US16/987,934 Active 2036-12-27 US11518499B2 (en) | 2016-09-30 | 2020-08-07 | Nacelle for an aircraft aft fan |
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US16/987,934 Active 2036-12-27 US11518499B2 (en) | 2016-09-30 | 2020-08-07 | Nacelle for an aircraft aft fan |
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Also Published As
Publication number | Publication date |
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EP4292939A2 (en) | 2023-12-20 |
US11518499B2 (en) | 2022-12-06 |
EP4292939A3 (en) | 2024-03-20 |
CN108327915A (en) | 2018-07-27 |
US20210107631A1 (en) | 2021-04-15 |
EP3351475A1 (en) | 2018-07-25 |
EP3351475B1 (en) | 2023-12-13 |
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