GB2237254A - Secondary lifting surfaces using separated flow - Google Patents

Secondary lifting surfaces using separated flow Download PDF

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Publication number
GB2237254A
GB2237254A GB8923962A GB8923962A GB2237254A GB 2237254 A GB2237254 A GB 2237254A GB 8923962 A GB8923962 A GB 8923962A GB 8923962 A GB8923962 A GB 8923962A GB 2237254 A GB2237254 A GB 2237254A
Authority
GB
United Kingdom
Prior art keywords
attack
lift
angle
lifting surfaces
incidence
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
GB8923962A
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GB8923962D0 (en
Inventor
Richard Harry Barnard
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Individual
Original Assignee
Individual
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
Application filed by Individual filed Critical Individual
Priority to GB8923962A priority Critical patent/GB2237254A/en
Publication of GB8923962D0 publication Critical patent/GB8923962D0/en
Publication of GB2237254A publication Critical patent/GB2237254A/en
Withdrawn legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C23/00Influencing air flow over aircraft surfaces, not otherwise provided for
    • B64C23/06Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices
    • B64C23/065Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips
    • B64C23/069Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips using one or more wing tip airfoil devices, e.g. winglets, splines, wing tip fences or raked wingtips
    • B64C23/072Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips using one or more wing tip airfoil devices, e.g. winglets, splines, wing tip fences or raked wingtips the wing tip airfoil devices being moveable in their entirety
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C3/00Wings
    • B64C3/38Adjustment of complete wings or parts thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C9/00Adjustable control surfaces or members, e.g. rudders
    • B64C9/34Adjustable control surfaces or members, e.g. rudders collapsing or retracting against or within other surfaces or other members
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00Aeronautics or air transport
    • Y02T50/10Drag reduction

Abstract

A secondary lifting surface 1, 2 which is capable of generating lift by means of conical or separated vortices at high angles of attack is movable so that its incidence may be changed relative to that of the primary lifting surface 3. When raised to an angle of attack sufficient to generate separated vortices, the surface generates a high lift coefficient, and is not prone to stalling in the conventional sense. Additionally, if raised to a sufficient angle of attack, its rate of increase of lift coefficient with change of angle of attack reduces, reducing the sensitivity to disturbance by gusts. The surfaces 1, 2 may be at the ring tips, or may be retractable into the main lift surfaces (Figs 2, 3). <IMAGE>

Description

AERODYNAMIC DEVICE UTILISING SEPARATED FLOW This invention relates to a device to modify the stalling and low-speed handling characteristics of an aircraft wing and other aerodynamic lifting surfaces.
In the flight of aircraft, there are numerous situations where it is necessary for the lifting surfaces to generate high values of lift coefficient, examples being the landing approach at low speed, and when pulling out of a dive. Due to the large angle of attack required in such situations, there is a danger that stalling of all or part of the wing may occur. In addition to causing a loss of lift, such stalling may also produce difficult or dangerous handling problems. In the latter respect, it is the stalling of the wingtips or outboard portions of the wing that is particularly significant.
Lifting surfaces with a high degree of leading-edge sweep such as slender delta wings generate stable separated flow in the form of conical vortices, and do not stall in the conventional sense.
Therefore, if a proportion of the overall lift force is generated by means of surfaces which produce conical vortex flow, then at high angles of attack, only the regions of conventional attached flow are susceptible to stalling.
A further feature of conical vortex-flow lift generation is that at high angles of attack, the rate of change of lift coefficient with angle of attack is relatively small in comparison with that for conventional attached-flow lift generation. The variation of lift due to gusting of the relative wind is therefore correspondingly smaller, and the aircraft response is less severe.
Wings utilising a mixture of donical vortex and conventional attached-flow lift are found on some existing aircraft types, but the the angle of attack of the surfaces generating the conical vortex flow can not be increased relative to that of the conventional attached-flow lifting surfaces. For this reason, the conical vortex flow lift can not reach anywhere near its maximum value without the likelihood of the flow separating over most of the other parts of the lifting surfaces. Furthermore, the angle of attack will not be sufficient to fully exploit the advantages of a low rate of change of lift coefficient with angle of attack outlined above.
lovable surfaces capable of generating stable conical vortex flow are sometimes employed, but for the purposes of control or for improving the flow over the main wing, not for generating a significant amount of the overall lift.
In the present invention, movable lifting surfaces are employed, the incidence of which may be varied relative to the incidence of other lifting surfaces. The movable surfaces may be adjacent to the tips of the other lifting surfaces, or may be disposed at any spanwise position.
The lovable surfaces have a planform in which the spanwise width increases towards the trailing edge, thus presenting swept leading edges in the manner of a delta wing. The degree of sweep is such that when the surfaces are raised to sufficiently large angles of attack, they generate stable conical vortices. Suitable sweep angles and the general geometric requirements for the generation of such conical vortex lift are well known in the art.
Such movable surfaces would normally be held at approximately the same incidence as the other lifting surfaces when the aircraft is flying at or near its normal cruising speed, but could be given a greater relative incidence in low speed flight in order to generate strong conical vortices.
Figure 1 shows one embodiment in which the surfaces are located at the outboard ends of the primary wing.
Figure 2 shows an alternative embodiment in which the surfaces may be retracted into the main wing.
Figure 3 shows the same embodiment as in figure 2, but with the surfaces extended out of the main wing.
In the first embodiment shown in figure 1, the surfaces 1 and 2 are located at the ends of the primary wing 3, so that the region of conical vortex flow can be obtained at those outboard positions. The surfaces may be rotated about an axis 4. This axis need not necessarily be in the direction of the wing major axis as shown, and the two surfaces need not rotate about the same axis.
In figure 1, the surfaces are shown inclined in incidence relative to the main wings, as would be the case when a high lift coefficient is required. The dotted lines indicate the positions that the surfaces would normally occupy in cruising flight.
In a second embodiment shown in figures 2 and 3, the surfaces 5 and 6 may be retracted so as to lie flush with the surface of the main wing in normal cruising flight, as shown in figure 2, or extended and inclined in incidence relative to the main wing so as to generate a high lift coefficient, as shown in figure 3. The surfaces are attached to the main wing by any suitable support and attachment mechanism 7 indicated in figure 3. Suitable mechanisms are well known in the art.

Claims (4)

1. A surface which forms part of the lift-generating surfaces of an aircraft or other vehicle, and which by virtue of its geometrical shape generates lift substantially by means of conical or stable separated vortices when inclined at large angles of attack, and for which, the incidence may be varied in relation to the incidence of the primary lifting surfaces.
2. A movable surface as claimed in clain 1, being located outboard of the primary lifting surfaces.
3. A movable surface as claimed in claim 1, be;ng retractable into the primary lifting surfaces.
4. A movable surface substantially as described herein with reference to figures 1,2 and 3, but for which the planform is not necessarily triangular.
GB8923962A 1989-10-25 1989-10-25 Secondary lifting surfaces using separated flow Withdrawn GB2237254A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8923962A GB2237254A (en) 1989-10-25 1989-10-25 Secondary lifting surfaces using separated flow

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8923962A GB2237254A (en) 1989-10-25 1989-10-25 Secondary lifting surfaces using separated flow

Publications (2)

Publication Number Publication Date
GB8923962D0 GB8923962D0 (en) 1989-12-13
GB2237254A true GB2237254A (en) 1991-05-01

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8923962A Withdrawn GB2237254A (en) 1989-10-25 1989-10-25 Secondary lifting surfaces using separated flow

Country Status (1)

Country Link
GB (1) GB2237254A (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19630681A1 (en) * 1996-07-30 1998-02-05 Gerhard Fink Rudder control surface for aircraft
DE10313290A1 (en) * 2003-03-25 2004-10-21 Eads Deutschland Gmbh Wing structure for aircraft, has outer wing that swivels relative to inner wing when it hits certain counter force to reduce high fluid mechanical loads affecting aircraft wing
WO2004092009A1 (en) * 2003-01-17 2004-10-28 Shangxiang Zhu A Wing ASSEMBLY CAPABLE OF INCREASIGN THE LIFT AND THE ANGLE OF STALL
GB2454588A (en) * 2007-11-07 2009-05-13 Boeing Co Aircraft wing with variable incidence tip
DE102009006212A1 (en) * 2009-01-27 2010-09-23 Fritz Unger Method for increasing lifting of e.g. aerofoil, for use in aerodynamically-flying aircraft, involves arranging body above another body in aerodynamic-flow, and moving aerofoil upwardly by parts during application of air flow
US8882470B2 (en) 2011-01-07 2014-11-11 Fritz Unger Rotor for a wind power generator
US9623960B2 (en) 2012-07-31 2017-04-18 Gabor Devenyi Aircraft wing having continuously rotating wing tips
US10370085B2 (en) 2016-05-27 2019-08-06 Lockheed Martin Corporation Body tab yaw deflector
US10486793B2 (en) 2016-05-27 2019-11-26 Lockheed Martin Corporation Yaw control in an aircraft
RU2790893C1 (en) * 2022-11-11 2023-02-28 Федеральное автономное учреждение "Центральный аэрогидродинамический институт имени профессора Н.Е. Жуковского" (ФАУ "ЦАГИ") Device for increasing lift performance of aircraft

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1343207A (en) * 1970-03-14 1974-01-10 Ver Flugtechnische Werke V/stol aircraft
US4776542A (en) * 1987-05-27 1988-10-11 Vigyan Research Associates, Inc. Aircraft stall-spin entry deterrent system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1343207A (en) * 1970-03-14 1974-01-10 Ver Flugtechnische Werke V/stol aircraft
US4776542A (en) * 1987-05-27 1988-10-11 Vigyan Research Associates, Inc. Aircraft stall-spin entry deterrent system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19630681A1 (en) * 1996-07-30 1998-02-05 Gerhard Fink Rudder control surface for aircraft
WO2004092009A1 (en) * 2003-01-17 2004-10-28 Shangxiang Zhu A Wing ASSEMBLY CAPABLE OF INCREASIGN THE LIFT AND THE ANGLE OF STALL
DE10313290A1 (en) * 2003-03-25 2004-10-21 Eads Deutschland Gmbh Wing structure for aircraft, has outer wing that swivels relative to inner wing when it hits certain counter force to reduce high fluid mechanical loads affecting aircraft wing
DE10313290B4 (en) * 2003-03-25 2005-12-29 Johannes Schweiger Fluid-mechanically effective surface of a moving in a fluid device, in particular an aircraft, in particular wing or rudder surface of an aircraft
GB2454588A (en) * 2007-11-07 2009-05-13 Boeing Co Aircraft wing with variable incidence tip
GB2454588B (en) * 2007-11-07 2010-01-20 Boeing Co Aircraft wing tip having a variable incidence angle
DE102009006212A1 (en) * 2009-01-27 2010-09-23 Fritz Unger Method for increasing lifting of e.g. aerofoil, for use in aerodynamically-flying aircraft, involves arranging body above another body in aerodynamic-flow, and moving aerofoil upwardly by parts during application of air flow
US8882470B2 (en) 2011-01-07 2014-11-11 Fritz Unger Rotor for a wind power generator
US9623960B2 (en) 2012-07-31 2017-04-18 Gabor Devenyi Aircraft wing having continuously rotating wing tips
US10370085B2 (en) 2016-05-27 2019-08-06 Lockheed Martin Corporation Body tab yaw deflector
US10486793B2 (en) 2016-05-27 2019-11-26 Lockheed Martin Corporation Yaw control in an aircraft
RU2790893C1 (en) * 2022-11-11 2023-02-28 Федеральное автономное учреждение "Центральный аэрогидродинамический институт имени профессора Н.Е. Жуковского" (ФАУ "ЦАГИ") Device for increasing lift performance of aircraft

Also Published As

Publication number Publication date
GB8923962D0 (en) 1989-12-13

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)