# US 7,461,820 B2 · Aerofoil arrangement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,461,820 B2 - Document ID: US7461820B2 - Status: Granted - Kind: B2 - Application number: 10/477,257 - Filed: 2002-05-09 - Published: 2004-12-16 - Granted: 2008-12-09 - Earliest claimed: 2001-05-11 - Inventors: Graham Bond Grove - Web page: https://patentgrep.com/patent/US7461820B2 ## CPC - B64C 3/48: by relatively-movable parts of wing structures - B64C 21/04: for blowing - B64C 2230/04: by actively generating fluid flow - B64C 2230/16: by blowing other fluids over the surface than air, e.g. He, H, O2 or exhaust gases - B64C 2230/28: at propeller or rotor blades - Y02T 50/10: Drag reduction - Y10S 416/05: Variable camber or chord length - B64C: AEROPLANES; HELICOPTERS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Upper surface (13) of an aerofoil (or rotor blade) is provided with nozzles or slots (14, 16) at leading portion (15) and trailing portion (17) to assist attachment of airflow by discharging gas towards trailing edge (11). Gas discharged may be heated, eg coming from rocket-type combustion chambers within the aerofoil. The aerofoil may be adjustable between high profile (as shown) and low profile (for supersonic flight) using jacks that pivot sections of upper surface (13) at leading and trailing edges (10-11). ## Claims ### Claim 1 An aerofoil having a chord length and a depth and which is adjustable between a high profile configuration for subsonic flow and a low profile configuration for supersonic flow, the aerofoil having an initial angle of attack to oncoming airflow of at least about 22 degrees, the aerofoil including a leading edge which generates a subsonic leading edge breakaway flow in the high profile configuration that comes from beneath the leading edge, an upper surface having a leading portion inclined away from the leading edge and a trailing portion rearward of the leading portion, a lower surface, and a trailing edge, wherein in the high profile configuration the depth of the aerofoil is at least about 30% of the chord length of the aerofoil so that the aerofoil is effective to reattach the leading edge breakaway flow and enables the aerofoil to operate with the initial angle of attack of at least about 22 degrees, and at least one opening provided along the leading portion of the upper surface and arranged to discharge a sufficient volume of gas away from the leading edge to reattach the leading edge breakaway flow to the upper surface. ### Claim 2 (depends on 1) An aerofoil according to claim 1, wherein the opening is in the form of a slot. ### Claim 3 (depends on 1) An aerofoil according to claim 1, wherein the openings comprise a series of apertures or nozzles spaced along the leading portion of the upper surface. ### Claim 4 (depends on 3) An aerofoil according to claim 3, wherein the apertures or nozzles are arranged to disperse the gas over the surface of the aerofoil. ### Claim 5 (depends on 4) An aerofoil according to claim 4, wherein the apertures or nozzles include substantially V-shaped apertures in their side walls. ### Claim 6 (depends on 4) An aerofoil according to claim 4, wherein the width of the outlet of each nozzle or aperture is greater than its height. ### Claim 7 (depends on 1) An aerofoil according to claim 1, wherein the upper leading surface portion is constituted by an upper leading panel and the upper trailing surface portion is constituted by an upper trailing panel. ### Claim 8 (depends on 7) An aerofoil according to claim 7, wherein the upper trailing panel is detachably joined to the remainder of the upper surface to facilitate movement between the high profile configuration and the low profile configuration. ### Claim 9 (depends on 8) An aerofoil according to claim 8, wherein the detachable joint is in the form of a sliding lap joint. ### Claim 10 (depends on 9) An aerofoil according to claim 9, wherein the sliding lap joint includes a roller rotatably mounted to the upper trailing panel which is slidable in a curved channel extending from the upper leading panel. ### Claim 11 (depends on 7) An aerofoil as claimed in claim 7, wherein the upper trailing panel is substantially planar. ### Claim 12 (depends on 1) An aerofoil according to claim 1, wherein the lower surface is defined by a leading panel, a central panel, and a trailing panel. ### Claim 13 (depends on 12) An aerofoil according to claim 12, wherein the lower leading panel and the lower trailing panel are hingedly connected to the lower central panel. ### Claim 14 (depends on 12) An aerofoil according to claim 12, wherein the lower central panel includes a transverse bend which defines a lower central panel leading portion and a lower central panel trailing portion. ### Claim 15 (depends on 12) An aerofoil according to claim 12, and including an upper leading panel, wherein the upper leading panel is fixedly attached to the lower leading panel at the leading edge. ### Claim 16 (depends on 12) An aerofoil according to claim 12, and including an upper trailing panel, wherein the upper trailing panel is fixedly attached to the lower trailing panel at the trailing edge. ### Claim 17 (depends on 12) An aerofoil according to claim 12, wherein the lengths of the lower leading panel and the lower trailing panel are significantly less than the length of the lower central panel. ### Claim 18 (depends on 1) An aerofoil according to claim 1, wherein the aerofoil includes two internal hydraulic jacks to facilitate adjustment between the low profile configuration and the high profile configuration. ### Claim 19 (depends on 1) An aerofoil according to claim 1, including two main structural support beams extending longitudinally of the aerofoil. ### Claim 20 (depends on 1) An aerofoil according to claim 1, wherein the leading edge is rounded. ### Claim 21 (depends on 20) An aerofoil according to claim 20, wherein the rounded leading edge includes a section through which cooling fluid or gas may pass to cool the leading edge. ### Claim 22 (depends on 20) An aerofoil according to claim 20, wherein the portion of the aerofoil adjacent to and including the leading edge includes a high temperature resistant layer. ### Claim 23 (depends on 22) An aerofoil according to claim 22, wherein the high temperature resistant layer comprises a ceramic material. ### Claim 24 (depends on 1) An aerofoil according to claim 1, including means to heat the gas. ### Claim 25 (depends on 24) An aerofoil according to claim 24, wherein the means to heat the gas comprises a combustion chamber within the aerofoil. ### Claim 26 (depends on 25) An aerofoil according to claim 25, wherein the means to heat the gas is a rocket chamber provided within the aerofoil which is arranged to exhaust heated gas to the opening(s). ### Claim 27 (depends on 26) An aerofoil according to claim 26, wherein the openings comprise a plurality of nozzles, and an arrangement is provided to exhaust heated gas from the rocket chamber to at least some of the plurality of nozzles. ### Claim 28 (depends on 26) An aerofoil according to claim 26, including one or more rocket chambers, with each opening comprising part of a respective rocket chamber. ### Claim 29 (depends on 24) An aerofoil according to claim 24, including means to heat the gas adjacent to but in operable connection with, the aerofoil. ### Claim 30 (depends on 1) An aerofoil according to claim 1, wherein at least one further opening is provided along a region of the upper surface between the opening(s) along the leading portion of the upper surface and the trailing edge, to discharge gas towards the trailing edge. ### Claim 31 (depends on 30) An aerofoil according to claim 30, wherein the further opening is in the form of a slot. ### Claim 32 (depends on 30) An aerofoil according to claim 30, wherein the further openings comprise a plurality of apertures or nozzles arranged along the trailing surface portion of the upper surface. ### Claim 33 (depends on 32) An aerofoil according to claim 32, wherein the apertures or nozzles in the trailing surface portion are arranged to disperse the gas over the trailing surface portion of the aerofoil. ### Claim 34 (depends on 33) An aerofoil according to claim 33, wherein the apertures or nozzles in the trailing surface portion include substantially V-shaped apertures in their side walls. ### Claim 35 (depends on 33) An aerofoil according to claim 33, wherein the width of the outlet of each aperture or nozzle in the trailing surface portion is greater than its height. ### Claim 36 (depends on 1) An aerofoil according to claim 1, wherein the aerofoil is a wing. ### Claim 37 (depends on 36) An aerofoil according to claim 36, which is movably attached to an aircraft such that its angle of incidence relative to a fuselage is selectively variable. ### Claim 38 (depends on 1) An aerofoil according to claim 1, wherein substantially the entire chord length of the upper and lower surfaces move relative to one another when the aerofoil is adjusted between the high profile and low profile configuration. ### Claim 39 An aerofoil having an initial angle of attack to oncoming airflow of at least about 22 degrees; a profile including a chord length and a depth, wherein the depth of the aerofoil is at least about 30% of the chord length of the aerofoil, the profile being such that a leading edge of the aerofoil generates a subsonic leading edge breakaway flow that comes from beneath the leading edge; a substantially continuous upper surface having a leading portion inclined away from the leading edge, and a trailing portion angled toward a trailing edge; a lower surface; and at least one opening provided in the leading portion of the upper surface and arranged to discharge gas away from the leading edge with the profile of the aerofoil being effective and the discharged gas being of sufficient volume to reattach the leading edge, breakaway flow to the upper surface, the profile further being such that the aerofoil is able to operate with the initial angle of attack of at least about 22 degrees. ### Claim 40 (depends on 39) An aerofoil as claimed in claim 39, further comprising at least one further opening along a region of the upper surface between the openings along the leading portion of the upper surface and the trailing edge, to discharge gas towards the trailing edge. ### Claim 41 (depends on 39) A rotor assembly comprising: a central support; a rotor including a plurality of radially oriented aerofoils distributed circumferentially around the central support; and gas supply means which carries pressurized gas from the central support to the aerofoils, wherein at least a majority of the aerofoils are as claimed in claim 39. ### Claim 42 (depends on 41) A rotor assembly as claimed in claim 41, wherein each of said at least a majority of the aerofoils further comprises at least one further opening along a region of the upper surface between the openings along the leading portion of the upper surface and the trailing edge, to discharge gas towards the trailing edge.