# US 2020/0400096 A1 · Variable area fan nozzle for turbofan aircraft engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0400096 A1 - Document ID: US20200400096A1 - Status: Published application - Kind: A1 - Application number: 16/772,480 - Filed: 2018-12-06 - Published: 2020-12-24 - Earliest claimed: 2017-12-15 - Assignees: Short Brothers PLC - Applicants: Short Brothers PLC - Inventors: Finbarr MCEVOY; Gary DAVISON - Web page: https://patentgrep.com/patent/US20200400096A1 ## CPC - F02K 1/805: {Sealing devices therefor, e.g. for movable parts of jet pipes or nozzle flaps} - F02K 1/09: by axially moving an external member, e.g. a shroud (F02K1/12 takes precedence) - F02K 1/72: the aft end of the fan housing being movable to uncover openings in the fan housing for the reversed flow - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2220/36: specially adapted for the fan of turbofan engines - F05D 2240/12: Fluid guiding means, e.g. vanes - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A variable area fan nozzle for a turbofan aircraft engine includes a first structure defining a forward portion of a bypass duct of the turbofan aircraft engine and a second structure defining an aft portion of the bypass duct. The second structure is movable relative to the first structure between a deployed position where a porting flow passage defined between the forward portion of the bypass duct and the aft portion of the bypass duct is open, and a stowed portion where the porting flow passage is closed. The movable second structure comprises a vane and a slat attached to the vane and disposed forward of the vane. The porting flow passage extends between the slat and the vane when the second structure is in the deployed position. ## Claims ### Claim 1 A variable area fan nozzle for a turbofan aircraft engine, comprising: a first structure defining a forward portion of a bypass duct of the turbofan aircraft engine; and a second structure defining an aft portion of the bypass duct disposed aft of the forward portion of the bypass duct, the second structure being movable relative to the first structure between a deployed position where a porting flow passage defined between the forward portion of the bypass duct and the aft portion of the bypass duct is open, and a stowed position where the porting flow passage is closed, the second structure comprising: a vane; and a slat attached to the vane and disposed forward of the vane, the porting flow passage extending between the slat and the vane when the second structure is in the deployed position. ### Claim 2 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein the slat is received in a cavity inside the first structure when the second structure is in the stowed position. ### Claim 3 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein the vane comprises a forward aerodynamic surface and the slat comprises an aft aerodynamic surface spaced apart from the forward aerodynamic surface of the vane, the forward aerodynamic surface of the vane and the aft aerodynamic surface of the slat at least partially defining the porting flow passage. ### Claim 4 (depends on 3) The variable area fan nozzle as defined in claim 3, wherein the forward aerodynamic surface of the vane and the aft aerodynamic surface of the slat are both convex relative to the porting flow passage. ### Claim 5 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein the slat is attached to the vane via one or more brackets extending across the porting flow passage. ### Claim 6 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein: the slat is sealed with the first structure when the second structure is in the deployed position; and the vane is sealed with the first structure when the second structure is in the stowed position. ### Claim 7 (depends on 1) The variable area fan nozzle as defined in claim 1, further comprising a radially-outer sealing element configured and disposed to provide a radially-outer sealed interface between the first structure and the second structure. ### Claim 8 (depends on 7) The variable area fan nozzle as defined in claim 7, wherein the radially-outer sealing element is attached to the first structure and comprises: a radially-outer vane sealing portion for interfacing with the vane when the second structure is in the stowed position; and a radially-outer slat sealing portion for interfacing with the slat when the second structure is in the deployed position. ### Claim 9 (depends on 8) The variable area fan nozzle as defined in claim 8, wherein the radially-outer sealing element is sealingly engaged with a radially-outer skin of the vane when the second structure is in the stowed position. ### Claim 10 (depends on 7) The variable area fan nozzle as defined in claim 7, wherein the radially-outer sealing element is a leaf-type seal. ### Claim 11 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein: the slat comprises an aft aerodynamic surface spaced apart from the vane; the aft aerodynamic surface of the slat at least partially defines the porting flow passage; and the slat comprises a portion other than the aft aerodynamic surface of the slat for interfacing with a radially-outer sealing element attached to the first structure. ### Claim 12 (depends on 11) The variable area fan nozzle as defined in claim 11, wherein the portion other than the aft aerodynamic surface of the slat is defined by a protrusion disposed on a side of the slat opposite the aft aerodynamic surface of the slat. ### Claim 13 (depends on 1) The variable area fan nozzle as defined in claim 1, further comprising a radially-inner sealing element configured and disposed to provide a radially-inner sealed interface between the first structure and the second structure. ### Claim 14 (depends on 13) The variable area fan nozzle as defined in claim 13, wherein the radially-inner sealing element is attached to the first structure and comprises: a radially-inner vane sealing portion for interfacing with the vane when the second structure is in the stowed position; and a radially-inner slat sealing portion for interfacing with the slat when the second structure is in the deployed position. ### Claim 15 (depends on 14) The variable area fan nozzle as defined in claim 14, wherein the radially-inner sealing element is configured to provide a sealed interface between the forward and aft portions of the bypass duct when the second structure is in the stowed position. ### Claim 16 (depends on 14) The variable area fan nozzle as defined in claim 14, wherein the radially-inner sealing element comprises a tongue extending from a main body, the radially-inner vane sealing portion and the radially-inner slat sealing portion comprising different sides of the tongue. ### Claim 17 (depends on 16) The variable area fan nozzle as defined in claim 16, wherein the tongue is configured and located to contact a surface of the slat facing the porting flow passage. ### Claim 18 (depends on 16) The variable area fan nozzle as defined in claim 16, wherein the main body of the radially-inner sealing element is hollow. ### Claim 19 (depends on 16) The variable area fan nozzle as defined in claim 16, wherein the radially-inner sealing element comprises a stiffener made from a material different from a material of the main body. ### Claim 20 (depends on 1) The variable area fan nozzle as defined in claim 1, wherein: the vane of the second structure at least partially defines a non-porting flow exit; and movement of the second structure from the stowed position to the deployed position causes an increase in an exit plane area of the non-porting flow exit. ### Claim 21 (depends on 1) The variable area fan nozzle as defined in claim 1, further comprising: a radially-outer sealing element configured and disposed to provide a radially-outer sealed interface between the first structure and the second structure; and a radially-inner sealing element configured and disposed to provide a radially-inner sealed interface between the first structure and the second structure. ### Claim 22 (depends on 1) A nacelle for a turbofan aircraft engine, the nacelle comprising the variable area fan nozzle as defined in claim 1.