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WO2024011283A1 - Surface portante à portance élevée - Google Patents

Surface portante à portance élevée Download PDF

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Publication number
WO2024011283A1
WO2024011283A1 PCT/AU2023/050640 AU2023050640W WO2024011283A1 WO 2024011283 A1 WO2024011283 A1 WO 2024011283A1 AU 2023050640 W AU2023050640 W AU 2023050640W WO 2024011283 A1 WO2024011283 A1 WO 2024011283A1
Authority
WO
WIPO (PCT)
Prior art keywords
aerofoil
wing
lift
modified
hyperbola
Prior art date
Application number
PCT/AU2023/050640
Other languages
English (en)
Inventor
Uli Kruger
Original Assignee
Kruger Performance Aviation Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2022901932A external-priority patent/AU2022901932A0/en
Application filed by Kruger Performance Aviation Pty Ltd filed Critical Kruger Performance Aviation Pty Ltd
Publication of WO2024011283A1 publication Critical patent/WO2024011283A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C3/00—Wings
    • B64C3/10—Shape of wings
    • B64C3/14—Aerofoil profile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C3/00—Wings
    • B64C3/10—Shape of wings
    • B64C3/14—Aerofoil profile
    • B64C2003/142—Aerofoil profile with variable camber along the airfoil chord
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/10—Two-dimensional
    • F05D2250/17—Two-dimensional hyperbolic
    • 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

Definitions

  • the present invention relates to aerofoils, and in particular an aerofoil adapted to utilise the lower/back surface of the aerofoil to increase lift.
  • the invention relates to aerofoils, both propellors and wings, and is equally applicable to both, but will be discussed primarily in relation to aircraft wings.
  • An aircraft wing is an aerodynamic lift surface where the dynamic pressure is lower on the top surface and higher on the lower surface to produce lift.
  • the net lift force is the differential force between the force on the lower surface and the force on the upper surface.
  • Lift The actual force pushing in the direction of what is termed to be “lift” comes from the wing’s lower surface.
  • Lift can be increased by either lowering the downward force on the upper wing surface by lowering the pressure, or increasing the upward force on the lower wing surface by increasing the pressure.
  • Conventional wings primarily produce lift by having a curved top surface to lower pressure, with the lower surface playing little or no role in providing lift beyond that of a flat surface.
  • Typical lower surface designs are aimed primarily at reducing drag.
  • the object of this invention is to provide an aerofoil with a bottom surface adapted to produce increased lift without unduly increasing drag, or at least provide the public with a useful alternative.
  • the invention provides an aerofoil for producing increased lift, comprising a lower surface is in the form of a convex section disposed towards a leading edge of the aerofoil and a concave section disposed towards a trailing edge of the aerofoil.
  • the convex section is in the form of a first hyperbola and the concave section is in the form of a second hyperbola.
  • the first hyperbola has a first focal length
  • the second hyperbola has a second focal length which is equal to the first focal length
  • the aerofoil further comprises an inflection point between the first hyperbola and the second hyperbola located midway between the leading edge and trailing edge of the aerofoil.
  • the aerofoil extends from a root to a tip, and the focal lengths of the first and second hyperbolas decreases from the root of the aerofoil to the tip of the aerofoil.
  • any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.
  • Figure 1 shows a side view of a wing chord modified in accordance with the invention.
  • Figure 2A shows a wing modified in accordance with the invention.
  • Figure 2B shows chords along the modified wing.
  • Figure 3A shows a root chord of a standard Zenith Zodiac wings.
  • Figure 3B shows a root chord of a Zenith Zodiac wing modified in accordance with the invention.
  • Figures 4A and 4B provide comparative pressure traces for the bottom surfaces of standard and modified Zenith Zodiac wings.
  • Figure 6 comparative power requirements of a standard and modified Liang Chi cooling tower fan.
  • Figures 7A, 7B and 7C show improvements in efficiency, thrust coefficient and power coefficient across a range of advance ratio for the modified Flynano blades.
  • the present provides an aerofoil which utilises the lower surface adapted to produce increased lift combining the advantages of both lift and pressure type fluid dynamic devices by producing pressure as well as lift without adversely affecting the lift/drag ratio.
  • the lower surface is in the form of a convex hyperbola towards the leading edge and a symmetrical concave hyperbola towards the trailing edge.
  • Fluid dynamic blades are devices to produce thrust, or lift, as a result of fluid flow over the blade surface.
  • the thrust/lift is the sum of the positive pressure on the back and negative pressure on the front of the blade.
  • the majority of thrust/lift is produced from the negative pressure component with only a small portion attributed to the positive pressure side. This results in high relative conversion efficiency compared to drag type surfaces which generate thrust by positive pressure only.
  • Drag type devices do have better low velocity performance compared to lift type devices but max out due to friction drag at higher flow velocities.
  • the back side or pressure side of the profile of the invention is comprised of a contour constructed from hyperbolic geometry.
  • the pressure side profile of hyperbolic sections with increasing focal length towards the air foil hub to. This provides relatively higher pressure increases towards the hub to provide greater stability, and to minimise the effect on any control surfaces which are typically towards the tip.
  • the surface is divided longitudinally comprising a convex hyperbolic surface towards the leading edge and a concave mirror shape towards the trailing edge.
  • the conjugate axis for the curve sections may be rotated along the centre line to achieve the appropriate blade twist in order to reduce the angle of attack from hub to the tip.
  • FIG. 1 shows a side view of a wing chord 10 with a bottom section in accordance with the invention.
  • a convex hyperbolic curve 12 extends from the leading tip 11 to an inflection point 13 halfway along the chord.
  • a concave hyperbolic curve 14 extends from the inflection point to the trailing tip 15.
  • the convex and concave hyperbolic curves are symmetrical in being the same length and with the same focal length. Tests have shown a larger focal length has a more pronounced affect, however the actual focal length that can be used in practise is limited by mechanical limitations on wing structure to ensure adequate strength and internal space. The actual form of the curves may also need to be compromised towards the leading and trailing tips to transition smoothly to the top section of the chord.
  • Figure 2A shows a wing 20 with a bottom surface 21 in accordance with the invention
  • Figure 2B shows wing chords at intervals along the wing.
  • the chord 10 closest to the root 25 of the wing 20 shows a bottom edge with a clearly discernible convex hyperbolic curve 12 towards the leading edge of the wing 22 and a concave hyperbolic curve 14 towards the trailing edge of the wing 24.
  • the hyperbolic curves can be seen to have decreasing focal length until the chord 10’ at the wing tip 26 has no discernible hyperbolic curves. This gives maximum effect (i.e. increased lift) towards the wing root, and minimal effect towards the wing tip.
  • a wing 30 from a Zenith Zodiac CH601 XL is modified in accordance with the invention to form a modified wing 30’.
  • Root chords from a standard wing are shown in Figure 3A and a modified wing in Figure 3B.
  • the standard wing 30 has a convex top surface 38 tapering towards the trailing edge.
  • the top surface 38’ of the modified wing 30’ remains unchanged from the standard wing.
  • the bottom surface 31 of the standard wing is flat, whereas the bottom surface 31 ’ of the modified wing has a convex hyperbolic front section 42’ extending from the leading edge 32’ to an inflection point 43’ midway along the chord where the surface changes to a concave hyperbolic rear section 44’ extending to the trailing edge 33’.
  • the modified wing 30’ achieved a 11% increase in the lift coefficient (lift - drag) and also a 1 .3% increase in the lift/drag ratio compared to the standard wing 30.
  • Figures 4A and 4B provide comparative pressure traces for the bottom surfaces 31 , 31 ’ of the standard 30 and modified 30’ wings at 200 km/h and a 3-degree angle of attack.
  • the modified wing 30’ shows a region with a marked increase in pressure 36’ towards the leading edge 32’ and root 34’, corresponding with the convex hyperbolic curve with maximum focal length, and a region with a marked decrease in pressure 37’ towards the trailing edge 33’ and root 34’, corresponding with the concave hyperbolic curve with maximum focal length.
  • Comparative pressure traces for the top surfaces of the standard and modified wings show now discernible difference showing that the modification to the bottom surface of the wing has had little if any effect on the performance of the top side of the wing. Similar results are seen for pressures traces at 70 km/h and a 15-degree angle of attack (not shown).
  • Comparative flow trajectory traces for the top surface of the wings also show that the modification to the underside of the wing has little if any effect on the performance of the top side of the wing. Similar results are seen for flow traces at 70 km/h and a 15-degree angle of attack (not shown).
  • a NACA 1412 Aerofoil is modified in accordance with the invention.
  • the modified aerofoil is also scaled down from a surface area of 8.37 m 2 to a surface area of 6.12 m 2 without limiting performance or efficiency. Additional 25% of lift/th rust is generated on the pressure side of the air foil.
  • the modified aircraft wing delivering the same lift with reduced surface area, is overall more efficient due to the reduction in material and weight.
  • an aircraft propeller is modified in accordance with the invention delivering the same thrust with reduced diameter, achieving higher flow velocities before the critical sonic tip speed limit is reached. In the example, a 25% increase in efficiency is achieved.
  • a static fan blade being a 1 .5 m diameter Liang Chi cooling tower fan, is modified in accordance with the invention.
  • Figure 5 compares the power required to drive the two fans at different flow rates, with the modified fan achieving approximately 12% reduction in input power.
  • blades from a quadcopter are modified in accordance with the invention.
  • the modified blade shows a 100% increase in efficiency at advance ratio of J 0.5 and a 66% increase in the thrust coefficient at J 0.
  • FIG. 6A, 6B and 6C show improvements in efficiency, thrust coefficient and power coefficient across a range of advance ratio.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

L'invention concerne une surface portante combinant les avantages de dispositifs de dynamique des fluides à la fois de type de portance et de pression dans laquelle la surface inférieure se présente sous la forme d'une hyperbole convexe vers le bord d'attaque et d'une hyperbole concave symétrique vers le bord de fuite, ce qui permet d'obtenir une portance accrue sans affecter négativement la finesse aérodynamique.
PCT/AU2023/050640 2022-07-11 2023-07-11 Surface portante à portance élevée WO2024011283A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2022901932A AU2022901932A0 (en) 2022-07-11 High Lift Aerofoil
AU2022901932 2022-07-11

Publications (1)

Publication Number Publication Date
WO2024011283A1 true WO2024011283A1 (fr) 2024-01-18

Family

ID=89535041

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2023/050640 WO2024011283A1 (fr) 2022-07-11 2023-07-11 Surface portante à portance élevée

Country Status (1)

Country Link
WO (1) WO2024011283A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4455003A (en) * 1977-03-23 1984-06-19 Vfw Supercritical air-foil profile
EP1112928A2 (fr) * 1999-12-31 2001-07-04 DLR Deutsches Zentrum für Luft- und Raumfahrt e.V. Profil aérodynamique avec bord de fuite améliorant la performance
CN106545453B (zh) * 2015-09-23 2019-04-16 东方电气集团东方电机有限公司 潮流能水轮机转轮及其水轮机
EP3581484A1 (fr) * 2018-06-14 2019-12-18 Airbus Helicopters Profils aerodynamiques a efficacite stabilisatrice amelioree pour empennages et derives

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4455003A (en) * 1977-03-23 1984-06-19 Vfw Supercritical air-foil profile
EP1112928A2 (fr) * 1999-12-31 2001-07-04 DLR Deutsches Zentrum für Luft- und Raumfahrt e.V. Profil aérodynamique avec bord de fuite améliorant la performance
CN106545453B (zh) * 2015-09-23 2019-04-16 东方电气集团东方电机有限公司 潮流能水轮机转轮及其水轮机
EP3581484A1 (fr) * 2018-06-14 2019-12-18 Airbus Helicopters Profils aerodynamiques a efficacite stabilisatrice amelioree pour empennages et derives

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
OODA IMAN JABBAR: "Effect of Flap on the Aerodynamic Characteristics of Supercritical Airfoil RAE 2822", JOURNAL OF MECHANICAL ENGINEERING RESEARCH AND DEVELOPMENTS, vol. 44, no. 9, 1 January 2021 (2021-01-01), pages 15 - 23, XP093129775, ISSN: 1024-1752 *

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