It is known to provide an aerofoil wing with lift-augmenting flaps which may be positioned at the wing leading edge or at the wing trailing edge. Traditionally such flaps rely on increasing the wing area by extending the flap forwardly from the leading edge or rearwardly from the trailing edge, and amplifying the effective camber (curvature) of the wing cross-section by giving a leading edge flap a more negative angle of incidence than the main wing body or giving a trailing edge flap a more positive angle of incidence than the rest of the wing body.

It is also known, from W098/07622, to provide a lift-generating member in the shape of a wing but having a recess extending span-wise of the wing leading edge and opening into the upper surface of the wing body, there being a cross-flow fan rotor positioned in said recess, and extending spanwise of the wing body. This rotor is driven for rotation in a direction which causes the path of the fan rotor blades to move rearwardly in the region of their path where they are exposed to the airflow over the top of the wing body. It has been found that the vortex generated using such a leading edge rotor can be controlled in order to vary the lift generated by such a wing-like member and GB-A-2346348 discloses the use of a vane to control the vortex for varying the lift generated with such a lift-generating member, for example for controlling roll in the case of an aircraft having such a lift-generating member for each of its main planes.

US-A-3289979 discloses a high lift aeroplane wing which uses trailing edge flaps deflectable in the normal manner in order to increase camber of the wing section for increasing the lift co-efficient. In order to improve the airflow over the junction of the main wing and the flap, where problems normally arise from the discontinuity of the boundary layer airflow, an auto-rotating rotor is positioned on or near the pivot axis of the flap to be rotated by the airflow over the wing and flap surfaces. US-A-3289979 also acknowledges that prior to that rotating cylindrical structures driven by power sources in the aircraft had been provided in order to minimise the discontinuity over the junction between the wing and the flap.

US-A-4293110 discloses a swept wing having leading edge double-flaps comprising a main (aft-flap) body deflected downwardly for increasing the lift co- efficient, but provided with a smaller leading edge (fore-flap) portion which deflects upwardly relative to the aft-flap segment when in the lift-enhancing mode. Air is blown from a nozzle positioned slightly above the junction between the fore-flap segment and the aft-flap segment in order to generate a vortex over the upper surface of the aft-flap segment in the lift-enhancing mode.

GB-A-0612304 discloses positioning a rotor in the upper side of a wing with half the diameter of the rotor projecting above the wing surface at the half chord position. The disclosure shows a tri-plane with the main wing provided with a trailing edge flap of conventional form.

FR-A-2228168 discloses the formation of a vortex in a cavity between the main wing body and a trailing edge flap, with the intention that this created vortex avoids the formation of parasitic vortices. The vortex is created using blowing nozzles and/or sucking nozzles.

In accordance with the present invention we now propose a wing-like body including a lift augmentation device, comprising a main wing body and a displaceable auxiliary body defining a first, lift-augmenting configuration and a second, non- augmenting configuration and moveable to intermediate configurations therebetween, including means for generating a vortex extending spanwise of the wing-like body at the junction between the main wing-like body and the auxiliary lift- augmenting body; wherein the arrangement is such that, at a relatively lower pressure side of the wing body, the generated vortex rotates in a direction which causes the airflow in the vortex to be co-current with the nearby main airflow passing over the wing body and, at the relatively higher pressure side of the wing body, the flow of the vortex air is countercurrent with the nearby main airflow over the wing body.

Preferably the vortex is generated by a cross-flow rotor extending spanwise of the flap along the recess and connected to driving means which rotates the rotor in a direction to carry the rotor vanes cocurrent with the airflow over the convex upper surface of the flap.

Such an auxiliary lift augmentation member may for example be a leading edge flap or a trailing edge flap, and may even be associated with other auxiliary wing devices such as wing slats.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings in which:- Figure 1A is a schematic cross section of an aerofoil wing incorporating the lift augmentation device in accordance with the present invention, the wing being shown in"clean"configuration for cruising flight or high speed flight using a suitable propulsion means such as at least one reaction motor (rocket or gas turbine) or propellor ; Figure 1B shows the wing of Figure 1A with its configuration changed in order to expose the concave and convex surfaces of the aerofoil to the passing airflow but with little or no general change in the wing camber, for example during transition from high speed or cruising flight to approach speed, or when used to augment lift and thrust for take-off.

Figure 1C shows the wing of Figures 1A and 1B with the trailing edge flap deflected to increase the camber of the aerofoil, and illustrates displacement of the lift-augmenting cross-flow rotor and its associated vortex-confining shroud to begin to expose the upper part of the rotor to the passing airflow such that the rotor vanes passing cocurrent with the airflow over the convex surface of the wing project upwardly above the general upper surface of the wing, for example during transition from approach speed to landing speed or to further augment lift and thrust on take- off; Figure 1D shows the same wing as in Figures 1A to 1C, with the flap fully deflected in the landing position and with the rotor and shroud pivoted upwardly to expose even more of the path of the rotor vanes to the airflow passing over the upper surface of the aerofoil, to generate high lift at landing; Figure 2A shows an alternative form of aerofoil wing with a transversely extending cross-flow rotor enclosed within the wing near its leading edge, but with the wing in clean configuration for cruising or high speed flight using a suitable propulsion means; Figure 2B shows the wing of Figure 2A with a slot exposed between the leading edge of the aerofoil and the main wing body, so as to expose the spanwise extending cross-flow rotor to the airflow moving over the upper (convex) and lower (usually concave) surfaces of the wing; Figure 2C shows the wing of Figures 2A and 2B with the leading edge extended forwardly, in the manner of a leading edge flap, but additionally given a more negative angle of incidence so as to increase the camber of the wing, while at the same time the cross-flow rotor and its vortex-confining shroud are pivoted upwardly so as to cause the upper part of the path of the rotor vanes to project above the convex upper surface of the wing body to encounter the airflow over the convex upper surface of the wing body, during transition from approach speed to landing speed or to augment thrust and lift on take-off; Figure 2D shows the wing of Figures 2A to 2C with the leading edge portion still further extended and deflected downwardly to further increase the camber of the wing, and with the tangential flow rotor and vortex-confining shroud pivoted still further upwardly to increase the degree of projection of the upper part of the fan vane path above the convex upper surface of the wing for generating high lift at landing ; Figure 3A shows a third embodiment of a wing in accordance with the present invention, with a vortex-confining shroud incorporated in the front of a trailing edge wing flap and with the wing in clean configuration for cruising on a high speed flight; and Figure 3B shows the wing of Figure 3A with the trailing edge flap extended rearwardly and deflected downwardly to increase the wing camber and to open a slot between the upper and lower surfaces of the wing through which air passes and generates a vortex in the vortex-confining recess but without the presence of a driven cross-flow fan, for generating high lift at landing.

Referring now to the drawings, Figure 1A shows an aerofoil wing-like body 1 comprising a main aerofoil portion 3 truncated at its trailing edge but supplemented by a trailing portion 5 such that, together, the portions 3 and 5 define an aerofoil section to the wing 1.

Positioned between the main (3) and trailing (5) portions of the wing body is a cross-flow rotor 7 having blades 8 extending spanwise of the wing 1 and able to orbit about a rotation axis 9 extending parallel to the wing span. The part of the rotor facing the trailing wing portion 5 defines a concave recess 11 extending spanwise of the wing 1 and pivotable about an axis 13 close to the convex upper surface of the wing 1 near the leading part of the trailing wing portion 5. In Figure 1A the wing 1 is clean in that the angle of incidence of the trailing wing portion 5 is substantially the same as that of the main wing portion 3 so that the aerofoil of the wing defines continuous surfaces at the junction between the main wing portion 3 and the trailing wing portion 5. In other words the cross-flow rotor 7 is totally isolated from the airflow passing over the convex upper surface and the concave lower surface of the wing 1. In this configuration the wing is configured for high speed flight or cruising flight using a suitable propulsion means.

Figure 1B shows the wing of 1A when adapted for augmenting the lift normally generated by the wing as a consequence of its forward flight. The rotor 7 is shown to be rotating in the anti-clockwise direction about the rotation axis 9, such that the rotor blades 8 and the generated vortex rotate in a direction which causes the airflow in the vortex to be co-current with the main airflow passing over the wing body at a relatively lower pressure side of the wing body and the rotor blades 8 and the flow of the vortex air to be countercurrent with the main airflow over the wing body in the relatively higher pressure region around the wing body. Furthermore the extension of the trailing wing portion 5 rearwardly with respect to the main wing portion 3 has opened a slot between the convex upper surface and the concave lower surface of the wing 1 so as to allow airflow to pass upwardly from the relative higher air pressure region below the wing to the relatively lower air pressure region above the wing. This upward passage of the air through a slot reference 15 is augmented by the rotation of the rotor 7 with its blades 8 moving cocurrent with the airflow through the slot 15.

In the Figure 1B configuration the rotor 7 and the shroud 11 are in the same configuration relative to the trailing wing portion 5 as they are in Figure 1A. There is therefore a degree of lift and thrust augmentation without any undue"dirtying"of the wing configuration in that drag will inevitably be somewhat higher than in the Figure 1A configuration, but will not be increased unduly in that the rotor is still within the overall aerofoil shape of the wing 1 rather than projecting clear of it into the passing airflow. In Figure 1B, the camber of the aerofoil section is somewhat higher than it is in Figure 1A whereas in Figure 2B the camber is unchanged from that of Figure 2A.

In both cases (Figures 1B and 2B) the camber is such that the wing is still substantially as clean as in the cleanest configuration (Figures 1A and 2A respectively).

In the Figure 1B configuration the wing is suitable for transition from high speed or cruising flight to approach speed, or indeed in order to augment lift and thrust for take-off. Just as in WO-A-98/02766 the rotation of the rotor 7 in the anti- clockwise direction shown in Figure 1B may well generate thrust which will augment the general thrust generated by the propulsion means of an aircraft incorporating the wing of Figures 1A to 1D. These propulsion means may for example comprise propellers driven by piston engines, or thrust-generating gas turbine engines, or turbo prop assemblies with propellers driven by gas turbine engines. Other propulsion means may of course be acceptable for use with the wing of Figures 1A to 1D.

Figure 1C shows the wing of Figure 1B with the wing trailing part 5 deflected downwardly so as to increase the overall camber of the wing 1, and now with the vortex-confining shroud 11 displaced slightly relative to the wing trailing body 5 by pivoting anti-clockwise about the pivot axis 13 so as to move the lower part 11 a of the shroud forwardly and upperwardly with respect to the leading edge of the under surface of the trailing part 5, and the rotor 7 is similarly displaced in an anti-clockwise direction relative to the trailing wing portion 5. As a result of this displacement the upper part of the path of the vanes of the cross-flow rotor 7 projects upwardly of the convex upper surface of the wing 1 so as to encounter airflow over the upper surface, moving from the leading edge to trailing edge of the wing 1, and thereby to exert a greater thrusting effect on the airflow as a result of the driven anti-clockwise rotation of the fan rotor 7. This both increases the degree of thrust generated by the rotor 7 and additionally results in attachment of the airflow over a greater length of the upper surface of the trailing wing 5 as a result of the higher airflow over a greater length of the upper surface 5b.

Preferably the rotor rotation axis 9 and the shroud 11 move in unison about the pivot axis 13 so as to maintain a constant positioning between the rotor 7 and the shroud 11 for the purpose of maintaining the quality of the vortex generated within the spanwise extending recess defined by the shroud 11. However, for the purposes of controlling that vortex it may be desirable to cause differential movement of the fan rotation axis 9 and the shroud 11 during this anti-clockwise movement between the position of Figure 1B and that of Figure 1C.

As is clearly visible in Figure 1C, the trailing wing portion 5 has not only pivoted anti-clockwise to increase the camber of the wing 1 but has also been extended further rearwardly with respect of the Figure 1B configuration so as to increase still further the effective wing area of wing 1. In this configuration the wing is well suited for the transition from approach speed to landing speed, or to augment still further thrust and lift for take-off.

The final position, shown in Figure 1D, is one in which the pivoting of the shroud 11 and the fan rotation axis 9 about the pivot axis 13 is still more pronounced so as to increase the degree of projection of the path of the blades of the cross-flow rotor 7 into the rearwardly moving airflow over the convex upper surface of the wing body 1, thereby still further increasing the tendency of the airflow to remain attached over the upper surface 5b of the trailing wing portion 5 and equally still further increasing the thrust effect of the driven rotor 7 on the airflow.

The slot 15 shown in Figure 1C is wider than the corresponding slot discussed above with reference to Figure 1B, and correspondingly that same slot becomes still wider in the Figure 1D configuration. Figure 1D shows the wing in maximum lift configuration for landing.

Although above we refer to the lower surface of the wing as being the concave surface, it will of course be appreciated that not all aerofoils exhibit concave lower surfaces so that undersurface may equally be straight or even mildly convex.

Although the above description refers to the slot 15 being opened as the trailing wing portion 5 moves rearwardly during its extension, it is equally possible for the slot to be opened by retraction of sliding doors which normally close the slot for high speed or cruising flight but which serve to open the slot even before the rearward extension of the trailing wing portion 5 has occurred.

As mentioned above, there is a degree of thrust augmentation as a result of the rotation of the driven fan 7 in the configurations of Figures 1B, 1C and 1D. It is considered that this will enable the main propulsion means to be somewhat rested during the flight in the lower speed regions of the flight envelope, and under certain conditions it may even be possible for all of the thrust to be generated by the rotation of fan rotor 7 so as to dispense with the need for thrust from main propulsion means.

If desired, the shroud 11 may additionally include a control means similar to that disclosed and claimed in GB-A-2346348 for the purposes of controlling the vortex within the generally cylindrical span-wise recess defined by the shroud 11. It has been found that the lift augmentation resulting from the positioning of a cross- flow rotor near the leading edge of a wing-like body (in this case the wing trailing portion 5 which in some ways resembles the wing illustrated in WO A-98/2766), is due to the existence of the vortex within the recess defined by the shroud 11 and at least partially intersecting the path of the vanes of the rotor 7.

Referring now to Figures 2A to 2D, there will be seen an alternative embodiment in which the wing-like member 21 includes a cross-flow rotor 27 between a leading portion 25 defining the leading edge of the wing and a main wing body portion 23 defining the remainder of the aerofoil of the wing. Again, a slot 35 exists between the leading portion 25 and the main wing portion 23, and the forward- facing part of the path of the blades 28 of the fan 27 borders on the slot 35.

In Figure 2A, showing the"clean"configuration of the wing for high speed for cruising flight, the slot 35 is closed off from the region of relatively higher pressure air under the wing body 21 by means of a lower sliding door 35a, and likewise the slot is closed off from the relatively lower pressure region of air above the convex upper surface of the wing body 21 by an upper sliding door 35b. Retraction of these doors into either the leading portion 25 or the main wing portion 23 (in this case the main wing portion 23) opens the slot 35 and allows to pass upwardly through it.

Although the effect of the driven rotation of the cross-flow fan rotor 27 is only exerted on the movement under the wing body 21 when the slot 35 is open, it may of course be desirable to maintain drive to the rotor 27 to keep it rotating about its rotation axis 29 even when the slot is closed, if only for the purposes of ensuring that as soon as the slot begins to open the rotor will already be rotating in the appropriate direction and with the desired speed. For this reason the fan rotor 27 is shown in Figure 2A as rotating in the anti-clockwise direction.

Figure 2B shows a configuration generally equivalent to that illustrated in Figure 1B but in this case there has been substantially no forward movement of the leading wing portion 25, but simply retraction of the two sliding doors 35a and 35b to open the slot 35 to the under and over the wing body 21. This illustrates the configuration for transition from high speed or cruising flight to approach speed. The effect of the vortex within the recess bounded by the shroud 31 is to increase the over the upper surface of the wing body 21, thereby augmenting lift and thrust and maintaining the over the convex upper surface attached until much closer to the trailing edge of the main wing portion 23. Although there would some extent be thrust augmentation as a result of the driving of the upwardly to the slot 35, as with the wing 1 of Figs. 1A to 1D, the effect of thrust augmentation begins to be more noticeable when the configuration of Figure 2C is reached. As in the case of Figure 1C, the shroud 31 has pivoted in the anticlockwise direction about the pivot axis 33, and carried the rotor 27 along with it as is evident from Figure 2C. Thus the upper part of the path of the blades 28 of the fan rotor 27 projects more noticeably into the passing over the upper surface of the wing body 21, increasing the thrust augmentation effect and still further increasing the tendency for the over the upper surface of the wing to remain attached up to the trailing edge.

Figure 2C also illustrates the fact that the wing leading portion 25 has begun to deflect downwardly and, although the mechanism for supporting and guiding the wing leading portion 25 is not shown in the drawings, the theoretical position of the centre of rotation 26 of the movement of the wing leading portion 25 is illustrated both in Figure 2C and in Figure 2D.

As in the case of Figure 1C the position illustrated in Figure 2C applicable to the transition from approach speed to landing speed or for augmenting lift and thrust for take off.

Likewise, configuration in Figure 2D shows still further anticlockwise pivoting of the rotor axis 29 and the shroud 31 about the pivot axis 33 and still further clockwise movement of the wing leading portion 25 to result in both a more negative angle of incidence of the wing leading portion and a further forward extension which increases the effective wing area of the wing 21 for landing.

The embodiment of Figures 2A to 2D has the advantage that the spanwise- extending cross-flow rotor is positioned at the thickest part of the aerofoil section.

Surprisingly it has now been discovered that the existence of the vortex at the recess defined in the leading portion of a wing body may under system circumstances result from without the need for a driving cross-flow fan rotor such as the rotor 7 in Figures 1A to 1D or the rotor 27 in Figures 2A to 2D. Such an arrangement is shown in Figures 3A and 3B where Figure 3B shows the high lift"landing" configuration where the through the slot between the trailing wing portion and the main portion of the wing body itself generates the required vortex.

In particular, Figure 3a shows a wing 41 comprising a main wing body portion 43 and a displaceable trailing wing portion 45 which is displaceable by virtue of pivoting around a theoretical axis 46 shown in both Figure 3A and Figure 3B. In Figure 3A, showing the most clockwise-displaced configuration of the trailing wing portion 45, the geometry is such that there is no slot existing between the main wing body portion 43 and the trailing wing body portion 45. However, once the trailing wing body portion 45 has begun to displace by anticlockwise rotation about the axis 46 from the configuration shown in Figure 3A, that slot 55 is open and is able to pass through the slot upwardly from the relatively higher pressure region below the wing body 41 through the area of relatively lower pressure air above the wing. In doing so, this will generate a vortex rotating in the anticlockwise direction as illustrated by the arrows 56 in Figure 3b, and this vortex is expected to have the same effect of augmenting lift of the wing 41 as was evident with the wing 1 of Figures 1A to 1D and the wing 21 of Figures 2A to 2D, without the need for the cross-flow rotor to generate the vortex.

Although Figure 3B illustrates the position generally equivalent to the configuration shown in Figure 1D, i. e. the high lift"landing"configuration, it will of course be understood that there are other configurations between the extreme of Figures 3A and 3B equivalent to the exemplary configurations shown in Figures 1B and 2B (transition from high speed or cruising flight to approach speed) and Figures 1C and 2C (transition from approach speed to landing speed or showing lift augmentation for take off).

The wing in accordance with the present invention may be used in a"self- propelling"mode which could do away with the need for a separate propulsion means. For example, the wing of Figures 1A to 1D could rely on the Figure 1C configuration for take-off in that the anticlockwise-rotating cross-flow fan 7 will generate a rearward flow of air over the upper surface of the wing trailing part 5 to propel the aircraft forwardly during the take-off run while the intake of air into the slot 15 from beneath the wing will not generate any appreciable rearward reaction (a reaction force acting in the direction towards the trailing edge of the wing trailing body 5). Indeed, the underside of the main wing portion 3 at the rear end near where the slot 15 opens may be shaped so as to facilitate flow of air into the slot 15 in a rearward direction (in a direction from the leading edge to the trailing edge of the wing 1) and, provided the magnitude of the airflow induced by the fan 7 is adequate, there will be a forward thrust on the wing which can cause the aircraft to gather momentum during the take-off run and achieve flying speed. The lift off speed will of course be enhanced (lowered) as a result of the partial downward deflection of the trailing wing part 5, in the manner of the trailing edge wing flap. After take-off the trailing wing portion 5 can be raised into the Figure 1B configuration where the same effect of thrusting flow generated by the cross-flow fan 7 will maintain forward thrust and maintain cruising flight.

For landing purposes, the trailing wing part 5 will initially be lowered to the Figure 1C configuration and then, for final approach, be lowered to the Figure 1D configuration where the maximum CL value will be obtained.

It will of course be appreciated that at no stage will the wing be cleaned up to the Figure 1A configuration, where no such thrusting flow can be generated by the totally enclosed cross-flow fan 7 even if the fan is rotating idly within its shut-off housing defined by the slot 15 on the one hand and the shroud 11 on the other hand.

The same effect can be achieved with the configuration of wing shown in Figures 2A to 2D in that, for take-off purposes, the wing may be set to the Figure 2C configuration so that airflow through the cross-flow fan 7 will be discharged rearwardly over the top surface of the main wing part 23 and taken in from beneath the leading wing part 25 in a generally rearward direction while the configuration of the leading wing part 25 resembles that of a leading edge wing flap. After the take-off phase, the wing can be set to the Figure 2B configuration in which, as in the case of Figure 1B, cruising flight may be maintained with merely the propelling effect of the rearwardly moving air discharged by the cross-flow fan 27 over the top surface of the main wing part 23, optionally assisted by a rearward direction of the airflow into the slot 35 from beneath the leading wing part 25. Again, as in the case of Figures 1A to 1D, the leading wing part 25 may be shaped at its under surface so as to facilitate entry of rearwardly moving air into the slot 35 from beneath the leading wing part 25. Such shaping may, for example, comprise blunting of the"nose"between the underside of the leading wing part 25 and the entry into the slot 35, or even raising of the undersurface of the leading wing part 25 so that it allows the air from beneath the leading wing part 25 to approach the fan rotor in a generally rearward and upward direction.

The Figure 2B configuration can be used for forward flight and the Figure 2C configuration can be used for the early stages of the landing approach, with the Figure 2D configuration used for the final approach where maximum CL values are required.

Although Figures 1A to 1D on the one hand, and Figures 2A to 2D on the other hand, illustrate positions of the cross-flow fan 7 or 27 at points where the transition between the main wing part 3 and the moving trailing wing part 5 of a conventional wing with trailing wing flap will arise (Figure 1B) or where the transition between the main wing part 23 and the leading wing part 25 of a wing with a leading edge flap will arise, this self-propelling configuration just discussed above may be improved by having the cross-flow fan rotor moved somewhat rearwardly from the position showing in Figures 2A to 2D, where the thickest part of the aerofoil will permit the maximum diameter of fan rotor 27 to be accommodated.

As indicated above, the configuration of Figures 1A to 1D showing the displaceable wing trailing portion, and likewise the configuration of Figures 3A and 3B showing such a displaceable trailing portion, are equivalent to a conventional trailing edge flap, and likewise the configuration shown in Figures 2A to 2D is generally equivalent to a conventional leading edge wing flap. However, the lift augmentation device may equally embody other wing configurations and may, for example, be incorporated in a moveable slat to generate a lift-augmenting slot between itself and the adjacent surface of the wing body.

Although throughout the above description the member 1,21 or 41 has been described as"wing-like"this member could be any other dynamic aerofoil plane such as a tailplane or a canard surface.