US3764092A - Circulation control airfoil system - Google Patents

Circulation control airfoil system Download PDF

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US3764092A
US3764092A US00095648A US3764092DA US3764092A US 3764092 A US3764092 A US 3764092A US 00095648 A US00095648 A US 00095648A US 3764092D A US3764092D A US 3764092DA US 3764092 A US3764092 A US 3764092A
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flap
airfoil
edge
blunt
trailing edge
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US00095648A
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R Williams
R Murphy
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US Department of Navy
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US Department of Navy
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C9/00—Adjustable control surfaces or members, e.g. rudders
    • B64C9/14—Adjustable control surfaces or members, e.g. rudders forming slots
    • B64C9/16—Adjustable control surfaces or members, e.g. rudders forming slots at the rear of the wing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C3/00—Wings
    • B64C3/10—Shape of wings
    • B64C3/14—Aerofoil profile
    • B64C3/141—Circulation Control Airfoils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C9/00—Adjustable control surfaces or members, e.g. rudders
    • B64C9/14—Adjustable control surfaces or members, e.g. rudders forming slots
    • B64C9/16—Adjustable control surfaces or members, e.g. rudders forming slots at the rear of the wing
    • B64C9/18—Adjustable control surfaces or members, e.g. rudders forming slots at the rear of the wing by single flaps

Definitions

  • the airfoil may be a supercritical type employing a flap which can be rotated to combine with the airfoil to produce a coanda profile or which can be used as a blown flap at transonic speeds when combined with a high velocity blowing jet over the flap.
  • the supercritical airfoil can include a slot in the underside of the foil for blowing a jet flap in lieu of the blown flap.
  • the prior art shows the blunt tail or circulation control airfoil utilizes tangential blowing.
  • the prior art additionally shows the use of a blown flap where circulation control is maintained over the surface of a flap by blowing ajet of air across it.
  • each of these devices have been used in a separate airfoil, each airfoil lacking the capability of changing its shape and adapting to both low speed and high speed operation.
  • a supercritical airfoil utilizing reverse camber near its trailing edge and designed for high speed, high mach number operation, comprises a flap at its trailing edge.
  • the flap aligns itself with the airfoil, becoming a part of the airfoil.
  • the supercritical airfoil shape is maintained, retaining its efficiency.
  • blowing can be initiated over the flap, altering the pressure distribution and developing increased lift.
  • the supercritical shape of the airfoil can be altered specifically to meet low speed requirements.
  • the flap can be rotated forming a blunt trailing surface or coanda profile with the airfoil.
  • a thin sheet of air is blown out over the length of the blunt edge through a series of nozzles arranged in a tangential slot, coextensive with the blunt edge and adjacent to it.
  • the thin slieet of air is blown tangentially out over the trailing edge and adheres to the trailing edge, detaching from the airfoil at a point on the foil underside, below the trailing edge and determined by the intensity of the blowing.
  • the circulation control over the blunt edge through tangential blowing increases the lift by a significant amount over a conventional airfoil, employing such devices as leading edge slots, trailing edge flap and boundary layer control in the leading and trailing edges.
  • FIGS. la, lb, and 1c shows in cross-section, the preferred embodiment airfoil with thei flap arranged for three modes of operation; FIG. Ia for high speed, FIG. lb for speeds approaching landing speeds, and FIG. lc for landing speed.
  • FIG. 2 shows an alternative embodiment, in crosssection, where for low speed operation the flap is arranged in a non-loaded floating position and exposing the airfoil blunt edge for circulation control tangential blowing.
  • FIG. 3 shows an alternative embodiment in crosssection, for high speed operation, utilizing the jet flap instead of the blown flap shown in FIG. Ia.
  • FIG. la wherein is shown the main wing or main airfoil 10 having the leading edge 11, a second edge 13, adjacent to flap l5, and a tangential slots 21 and 22, adjacent the flap.
  • Flap 15 is hinged to airfoil 10, by hinge pin 17.
  • the airfoil is shown in crosssection and slots 21 and 22 extend the length of the span.
  • the airfoil and the flap are arranged for high speed operation. In the high speed range, the foil and the flap form one continuous airfoil upper surface, except for the discontinuity introduced by slots 21 and 22.
  • Flap 15 is shaped to introduce a negative camber at area 19.
  • air shown by arrow 23
  • the blown flap changes the pressure distribution across the foil upper surface, dislacing the shock further aft on the airfoil, thus maintaining a larger working portion on the airfoil and developing increased lift.
  • FIG. lb shows the airfoil of FIG. 1a, in a low speed situation as when the aircraft is approaching a landing and requires increased flap angle.
  • the flap is rotated downward from the position assumed in FIG. 1a, to provide the increased flap angle.
  • a thin sheet of air, shown by arrow 25, is blown out of slot 21 and across the upper surface of flap 15 to provide increased blown flap lift as in the case of FIG. 1a.
  • FIG. 10 the flap 15 is rotated so that its under surface 18, is in contact with its mating surface 16, on the lower side of foil 10. In this position, the flap in conjunction with the foil, forms a blunt trailing surface denoted by bracket 29, over which a thin sheet of air flows as shown by arrow 27, and which is produced by tangential blowing out of slot 21.
  • FIG. 2 is shown an alternate embodiment, wherein flap 15 is moved aft of foil 10, in a free floating position, within the flow stream as shown by arrows 28 and 31, wherein no load on flap 15 is produced.
  • the flap 15 is displaced sufficiently aft of the foil 10, so that the coanda profile at blunt trailing edge 14, and the circulation of air blown from tangential slot 21, around the blunt trailing edge is uneffected by the presence of flap 15.
  • This embodiment would be used in substitution of the embodiment shown in FIG. 10, where the flap is rotated against the foil 10.
  • FIG. 3 is shown an alternative embodiment to that shown in FIG. 1a, for high speed or transonic operation wherein a jet flap is produced by blowing ajet of air 33 out of slot 32.
  • This arrangement would be in substitution of blowing air across the upper surface of flap 15, as shown in FIG. 1a.
  • the flap alters the pressure distribution as does the blown flap, to move shock on the upper surface aft, thereby developing a larger working portion of the airfoil for developing lift with the consequent result of higher lift.
  • the arrangement of FIG. 2, for moving the flap aft can be used with the arrangement in FIG. la, wherein air is blown from the tangential slot out across the upper surface of the airfoil or FIG.
  • FIG. 3 where the stream of air is blown out of slot 32, producing a jet flap.
  • the jet flap is produced by blowing out of slot within the flap can be used in low speed application by stopping the flow of air from slot 32 and rotating flap 15 to the position shown in FIG. 10, and blowing air tangentially out over the blunt surface 29, as shown in FIG. 1c, from the slot 21.
  • An additional slot 22 is shown on foil 10, forward of slot 21, is shown. This slot 22 is used to increase lift where the foil 10 is in a high angle of attack.
  • An airfoil producing high lift at low landing speeds and at transonic speeds comprising:
  • said flap being rotatable against the underside of said main wing to form a blunt trailing edge for circulation control blowing.
  • said main wing has a first slot disposed along its rearward edge adjacent said flap for tangentially blowing air over said blunt edge at low speeds and over said sharp edge at transonic speeds.
  • a lifting foil for producing high lift at low landing speeds and at transonic speeds comprising:
  • said flap having a sharp trailing edge
  • said flap being movable rearward of the main wing to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing.
  • said main wing has a first slot disposed along the trailing edge adjacent to said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds.
  • said airfoil has a negative camber portion on its upper surface for forming a supercritical airfoil.
  • An airfoil producing high lift at low landing speeds and at transonic speeds comprising:
  • a flap having a sharp trailing edge mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds;
  • said supercritical airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap;
  • An airfoil producing high lift at low landing speeds and at transonic speeds comprising:
  • a flap having a sharp trailing edge mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil;
  • said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds;
  • said supercritical airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap;
  • said flap has a slot in its bottom surface for blowing a jet of air through said slot to produce a jet flap where said flap is rotated to form a supercritical lifting foil with said airfoil.
  • a lifting airfoil for producing high lift at low landing speeds and at transonic speeds comprising:
  • said flap having a sharp trailing edge
  • said flap being movable rearward of the airfoil to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing;
  • said airfoil having a first slot disposed along the trailing edge adjacent said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds;
  • said flap being movable against said blunt trailing edge to form a substantially continuous lifting surface and said flap causing a negative camber portion on the upper surface of the entire airfoil for forming a supercritical airfoil with said lifting foil;
  • said flap having a slot in its underside for blowing a jet of air to produce a jet flap.

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

Abstract

A lifting airfoil has the capability of exhibiting a coanda profile, or blunt trailing edge for low speed landings capability, and a blown flap or jet flap for high speed transonic operation. The airfoil may be a supercritical type employing a flap which can be rotated to combine with the airfoil to produce a coanda profile or which can be used as a blown flap at transonic speeds when combined with a high velocity blowing jet over the flap. In addition, the supercritical airfoil can include a slot in the underside of the foil for blowing a jet flap in lieu of the blown flap.

Description

United States Patent [191 Williams et a].
[4 1 Oct. 9, 1973 CIRCULATION CONTROL AIRFOIL SYSTEM represented by the Secretary of the Navy 221 Filed: Dec. 7, 1970 21 Appl. No.: 95,648
[56] References Cited UNITED STATES PATENTS 3/1964 Alvarez-Calderon...l 244/42 DB 3/1968 Alvarez-Calderon 244/42 DB 3,447,763 6/1969 Allcock 244/42 DA Primary Examiner-Milton Buchler Assistant Examiner-Carl A. Rutledge Attorney-R. S. Sciascia and Q. E. Hodges [57] ABSTRACT A lifting airfoil has the capability of exhibiting a coanda profile, or blunt trailing edge for low speed landings capability, and a blown flap or jet flap for high speed transonic operation. The airfoil may be a supercritical type employing a flap which can be rotated to combine with the airfoil to produce a coanda profile or which can be used as a blown flap at transonic speeds when combined with a high velocity blowing jet over the flap. In addition, the supercritical airfoil can include a slot in the underside of the foil for blowing a jet flap in lieu of the blown flap.
12 Claims, 5 Drawing Figures Patented Oct. 9, 1-973 3,764,092
INVENTORS ROBERT M. WILLIAMS BY RICHARD D. MURPHY AT ORNEY CIRCULATION CONTROL AIRFOIL SYSTEM The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.
DESCRIPTION OF THE PRIOR ART The prior art shows the blunt tail or circulation control airfoil utilizes tangential blowing. The prior art additionally shows the use of a blown flap where circulation control is maintained over the surface of a flap by blowing ajet of air across it. However, each of these devices have been used in a separate airfoil, each airfoil lacking the capability of changing its shape and adapting to both low speed and high speed operation.
SUMMARY This invention pertains to an airfoil which is adaptable for high speed, transonic operation which is additionally adaptable for low speed landing applications. A supercritical airfoil utilizing reverse camber near its trailing edge and designed for high speed, high mach number operation, comprises a flap at its trailing edge. For high speed operation, the flap aligns itself with the airfoil, becoming a part of the airfoil. At cruising speed the supercritical airfoil shape is maintained, retaining its efficiency. At high mach or transonic speed and where a combat situation is encountered, requiring increased lift, blowing can be initiated over the flap, altering the pressure distribution and developing increased lift. For a low speed operation, the supercritical shape of the airfoil can be altered specifically to meet low speed requirements. The flap can be rotated forming a blunt trailing surface or coanda profile with the airfoil. A thin sheet of air is blown out over the length of the blunt edge through a series of nozzles arranged in a tangential slot, coextensive with the blunt edge and adjacent to it. The thin slieet of air is blown tangentially out over the trailing edge and adheres to the trailing edge, detaching from the airfoil at a point on the foil underside, below the trailing edge and determined by the intensity of the blowing. The circulation control over the blunt edge through tangential blowing, increases the lift by a significant amount over a conventional airfoil, employing such devices as leading edge slots, trailing edge flap and boundary layer control in the leading and trailing edges.
BRIEF DESCRIPTION OF THE DRAWINGS FIGS. la, lb, and 1c, shows in cross-section, the preferred embodiment airfoil with thei flap arranged for three modes of operation; FIG. Ia for high speed, FIG. lb for speeds approaching landing speeds, and FIG. lc for landing speed.
FIG. 2 shows an alternative embodiment, in crosssection, where for low speed operation the flap is arranged in a non-loaded floating position and exposing the airfoil blunt edge for circulation control tangential blowing.
FIG. 3 shows an alternative embodiment in crosssection, for high speed operation, utilizing the jet flap instead of the blown flap shown in FIG. Ia.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. la, wherein is shown the main wing or main airfoil 10 having the leading edge 11, a second edge 13, adjacent to flap l5, and a tangential slots 21 and 22, adjacent the flap. Flap 15 is hinged to airfoil 10, by hinge pin 17. The airfoil is shown in crosssection and slots 21 and 22 extend the length of the span. As shown in FIG. la, the airfoil and the flap are arranged for high speed operation. In the high speed range, the foil and the flap form one continuous airfoil upper surface, except for the discontinuity introduced by slots 21 and 22. Flap 15 is shaped to introduce a negative camber at area 19. For a transonic operation where high lift is required air, shown by arrow 23, is blown from slot 21, across the flap upper surface. The blown flap changes the pressure distribution across the foil upper surface, dislacing the shock further aft on the airfoil, thus maintaining a larger working portion on the airfoil and developing increased lift.
FIG. lb, shows the airfoil of FIG. 1a, in a low speed situation as when the aircraft is approaching a landing and requires increased flap angle. The flap is rotated downward from the position assumed in FIG. 1a, to provide the increased flap angle. In addition, a thin sheet of air, shown by arrow 25, is blown out of slot 21 and across the upper surface of flap 15 to provide increased blown flap lift as in the case of FIG. 1a.
FIG. 10, the flap 15 is rotated so that its under surface 18, is in contact with its mating surface 16, on the lower side of foil 10. In this position, the flap in conjunction with the foil, forms a blunt trailing surface denoted by bracket 29, over which a thin sheet of air flows as shown by arrow 27, and which is produced by tangential blowing out of slot 21.
Referring now to FIG. 2, is shown an alternate embodiment, wherein flap 15 is moved aft of foil 10, in a free floating position, within the flow stream as shown by arrows 28 and 31, wherein no load on flap 15 is produced. The flap 15 is displaced sufficiently aft of the foil 10, so that the coanda profile at blunt trailing edge 14, and the circulation of air blown from tangential slot 21, around the blunt trailing edge is uneffected by the presence of flap 15. This embodiment would be used in substitution of the embodiment shown in FIG. 10, where the flap is rotated against the foil 10.
In FIG. 3, is shown an alternative embodiment to that shown in FIG. 1a, for high speed or transonic operation wherein a jet flap is produced by blowing ajet of air 33 out of slot 32. This arrangement would be in substitution of blowing air across the upper surface of flap 15, as shown in FIG. 1a. The flap alters the pressure distribution as does the blown flap, to move shock on the upper surface aft, thereby developing a larger working portion of the airfoil for developing lift with the consequent result of higher lift. The arrangement of FIG. 2, for moving the flap aft can be used with the arrangement in FIG. la, wherein air is blown from the tangential slot out across the upper surface of the airfoil or FIG. 3, where the stream of air is blown out of slot 32, producing a jet flap. Similarly, in the arrangement of FIG. 3, wherein the jet flap is produced by blowing out of slot within the flap can be used in low speed application by stopping the flow of air from slot 32 and rotating flap 15 to the position shown in FIG. 10, and blowing air tangentially out over the blunt surface 29, as shown in FIG. 1c, from the slot 21.
An additional slot 22 is shown on foil 10, forward of slot 21, is shown. This slot 22 is used to increase lift where the foil 10 is in a high angle of attack.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is: 1
1. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising:
a main wing;
a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the main wing; and
said flap being rotatable against the underside of said main wing to form a blunt trailing edge for circulation control blowing.
2. The airfoil of claim 1, wherein:
said main wing has a first slot disposed along its rearward edge adjacent said flap for tangentially blowing air over said blunt edge at low speeds and over said sharp edge at transonic speeds.
3. The airfoil of claim 2 wherein said flap is rotatable to form a supercritical airfoil with said main wing; and said supercritical main wing having negative camber over the upper surface of said airfoil.
4. The lifting foil of claim 3 wherein said flap can be rotated between said blunt edge position and said supercritical airfoil position to form a continuous surface with the underside of said main wing for providing additional lifting surface.
5. The lifting foil of claim 3 wherein air is blown out said slot across the upper surface of said flap to form a blown flap.
6. A lifting foil for producing high lift at low landing speeds and at transonic speeds, comprising:
a main wing;
a blunt trailing edge on said main wing;
a flap disposed along said blunt trailing edge;
said flap having a sharp trailing edge;
said flap being movable rearward of the main wing to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing.
7. The airfoil of claim 6, wherein:
said main wing has a first slot disposed along the trailing edge adjacent to said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds.
8. The lifting foil of claim 7 wherein said flap is moveable against said blunt trailing edge to form a substantially continuous lifting surface.
9. The lifting foil of claim 8, wherein:
said airfoil has a negative camber portion on its upper surface for forming a supercritical airfoil.
10. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising:
a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds;
said supercritical airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap; and
a second slot in said airfoil parallel to said first slot and forward of said first slot.
11. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising:
a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil;
said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds;
said supercritical airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap; and
said flap has a slot in its bottom surface for blowing a jet of air through said slot to produce a jet flap where said flap is rotated to form a supercritical lifting foil with said airfoil.
12. A lifting airfoil for producing high lift at low landing speeds and at transonic speeds comprising:
a blunt trailing edge;
a flap disposed along said blunt trailing edge;
said flap having a sharp trailing edge;
said flap being movable rearward of the airfoil to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing;
said airfoil having a first slot disposed along the trailing edge adjacent said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds;
said flap being movable against said blunt trailing edge to form a substantially continuous lifting surface and said flap causing a negative camber portion on the upper surface of the entire airfoil for forming a supercritical airfoil with said lifting foil; and
said flap having a slot in its underside for blowing a jet of air to produce a jet flap.

Claims (12)

1. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising: a main wing; a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the main wing; and said flap being rotatable against the underside of said main wing to form a blunt trailing edge for circulation control blowing.
2. The airfoil of claim 1, wherein: said main wing has a first slot disposed along its rearward edge adjacent said flap for tangentially blowing air over said blunt edge at low speeds and over said sharp edge at transonic speeds.
3. The airfoil of claim 2 wherein said flap is rotatable to form a supercritical airfoil with said main wing; and said supercritical main wing having negative camber over the upper surface of said airfoil.
4. The lifting foil of claim 3 wherein said flap can be rotated between said blunt edge position and said supercritical airfoil position to form a continuous surface with the underside of said main wing for providing additional lifting surface.
5. The lifting foil of claim 3 wherein air is blown out said slot across the upper surface of said flap to form a blown flap.
6. A lifting foil for producing high lift at low landing speeds and at transonic speeds, comprising: a main wing; a blunt trailing edge on said main wing; a flap disposed along said blunt trailing edge; said flap having a sharp trailing edge; said flap being movable rearward of the main wing to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing.
7. The airfoil of claim 6, wherein: said main wing has a first slot disposed along the trailing edge adjacent to said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds.
8. The lifting foil of claim 7 wherein said flap is moveable against said blunt trailing edge to form a substantially continuous lifting surface.
9. The lifting foil of claim 8, wherein: said airfoil has a negative camber portion on its upper surface for forming a supercritical airfoil.
10. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising: a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds; said supercritical airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap; and a second slot in said airfoil parallel to said first slot and forward of said first slot.
11. An airfoil producing high lift at low landing speeds and at transonic speeds, comprising: a flap having a sharp trailing edge, mounted for pivoting movement along the rearward edge of the airfoil, said flap being rotatable against the underside of said airfoil to form a blunt trailing edge for circulation control blowing, wherein said flap is rotatable to form a supercritical airfoil with said lifting airfoil; said airfoil having a first slot disposed along its rearward edge adjacent to said flap for tangentially blowing air over said blunt edge at low speed and over said sharp edge at transonic speeds; said supercriticaL airfoil having negative camber over the surface of said airfoil, wherein air is blown out of said slot across the upper surface of said flap to form a blown flap; and said flap has a slot in its bottom surface for blowing a jet of air through said slot to produce a jet flap where said flap is rotated to form a supercritical lifting foil with said airfoil.
12. A lifting airfoil for producing high lift at low landing speeds and at transonic speeds comprising: a blunt trailing edge; a flap disposed along said blunt trailing edge; said flap having a sharp trailing edge; said flap being movable rearward of the airfoil to a free stream position, exposing the blunt trailing edge for circulation control by tangential blowing; said airfoil having a first slot disposed along the trailing edge adjacent said blunt edge for tangentially blowing air over said flap edge at transonic speeds and over said blunt edge at low speeds; said flap being movable against said blunt trailing edge to form a substantially continuous lifting surface and said flap causing a negative camber portion on the upper surface of the entire airfoil for forming a supercritical airfoil with said lifting foil; and said flap having a slot in its underside for blowing a jet of air to produce a jet flap.
US00095648A 1970-12-07 1970-12-07 Circulation control airfoil system Expired - Lifetime US3764092A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126173A (en) * 1964-03-24 Alvarez-calderdn
US3371888A (en) * 1965-07-12 1968-03-05 Alberto Alvarez Calderon Inverting flap system
US3447763A (en) * 1964-12-11 1969-06-03 Power Jet Research & Dev Ltd Flap systems for aircraft

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126173A (en) * 1964-03-24 Alvarez-calderdn
US3447763A (en) * 1964-12-11 1969-06-03 Power Jet Research & Dev Ltd Flap systems for aircraft
US3371888A (en) * 1965-07-12 1968-03-05 Alberto Alvarez Calderon Inverting flap system

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