[0001] This invention relates to aircraft.

[0002] In fixed wing aircraft the forward horizontal motion produces airflow over the wing in conventional manner. This horizontal motion presents the forward or leading edge of the wing to the oncoming air to cause an ever increasing airflow over the wing from the leading edge to the trailing edge of the wing as the aircraft gains speed. Molecules in the mainstream of air strike the front of the wing and move up and over and along the wing to the trailing edge. Due to the viscosity of the air, molecules in contact with the surface of the wing have a velocity of zero relative to the wing.

Molecules immediately above this layer have a slightly higher velocity in the direction of airflow and subsequent layers of molecules increase in velocity until the maximum velocity of the airflow, which is the total of ground speed and wind speed, is reached at the top portion of the aforedescribed airflow and layer. This layer is typically less than 25 mm deep from the surface of the wing. And is known as the "boundary layer" .

The boundary layer continues across the wing and is dissipated after the trailing edge. The viscosity of the boundary layer causes it to follow the cambered curve of the wing or aerofoil. As the boundary layer follows the curve of the wing downward (up to a maximum of some 15°) in relation to the air above cavities are formed in the air immediately above the boundary layer which is immediately filled from the atmosphere above. This process is repeated and its effect will be felt for many metres above the wing. The mass of us are being drawn downwards on to the wing can be many tons per second, in accordance with Newton's third law the wings will impart an equal upward force which results in lift.

[0003] Proposals have been made to use the above theory to cause lift on the wing or aerofoil while it is stationary. In Hansen (US 7, 201, 346) there is an arrangement wherein air is drawn into an aperture at the centre of an annular wing by a fan to provide propulsion for air drawing it from the leading edge of the wing to the aperture. As the air is drawn over the surface of the wing in a relatively uncontrolled manner the volume of the air needed to operate the Hansen arrangement becomes unpractically large. Sharpe (US 2,468,787) describes an arrangement wherein air is blown over the upper and lower services of two concentric annular wings. Here too large volumes of air at significant pressures are required for operation.

[0004] According to one aspect of the invention there is provided an aircraft including at least one control surface, most often a wing, having a downwardly sloping upper surface, and being characterised by a pressure chamber located close to the wing, pressure means for delivering air under pressure to the pressure chamber, a delivery nozzle for discharging air from the pressure chamber, the delivery nozzle being located at the upper surface of the control surface and extending over a substantial portion of the wing, the delivery nozzle being narrow and so located so as to enable it to discharge a narrow layer of air on to the upper surface to form a boundary layer thereon. The nozzle is designed to emit a layer of air which covers the upper surface and has a thickness of no more than 25 mm. The nozzle is preferably formed by a lip which overlies and is spaced from the upper surface. [0005] The aircraft conveniently has a pump which is located above the pressure chamber and which serves as the pressure means. The pump preferably has a vertical shaft. The pump may be located above the pressure chamber and has a vertically open inlet port there above. Alternatively the pump may be located below the pressure chamber and has a vertically open inlet port there below which is connected to a number of radial ambient inlet ports.

[0006] The aircraft preferably has propulsion means whereby it may propel it in horizontal flight during which the lift is provided by the wing in conventional manner.

[0007] Embodiments of the invention will now be described by way of example with reference to the accompanying drawings.

[0008] In the drawings:

Figure 1 is a diagrammatic transverse view of a detail of an aircraft of the invention; Figure 2 is a side view partially in section of another of a second embodiment of the invention, Figure 3 is an enlarged transverse section through the aircraft of Figure 2;

Figure 4 is a further enlarged detail showing the delivery nozzle of the aircraft of

Figure 2,

Figure 5 is a plan of the second embodiment of the invention, Figure 6 is a front view of a large aircraft embodying the invention, Figure 7 is a front view of a similar aircraft provided with canard wings,

Figure 8 is a transverse section through an aircraft wing of the invention, Figure 9 is a similar view of another wing of an aircraft of the invention, Figures 10 and 11 are front and side views of a personal commuter aircraft of the invention, Figure 12 is a detail transverse section through the wing and pressure chamber of a further embodiment of the invention, Figures 13 and 14 show a modified wing of an aircraft of the invention with a pressure chamber at the leading edge of the wing and with the wing in various positions relative to the pressure chamber,

Figure 15 is a diagrammatic view of a further modified aircraft of the invention. Figure 16 is a plan of a wing of yet another modified aircraft of the invention, Figure 17 is section on line 17 - 17 of Figure 16, and

Figure 18 is a perspective view of the wing of Figure 16,

[0009] Referring now to Figure 1 there is shown an aircraft 110 of the invention comprising a circular annular wing 112 projecting from the upper part of the fuselage 114. In the centre of the wing 112 is a circular section pressure chamber 116. A large central vertical funnel or air duct 118 is provided above the chamber 120 and within this duct 118 is a fan 122. The fan 122 is driven by the a propulsion engine (not shown).

[0010] The upper surface 124 of the wing 112 has the cambered form of a typical aircraft wing with the highest or leading edge 126 on the smaller inner diameter. The funnel 118 has an outwardly extending flange 128 at its lower end. The outer portion of the flange 128 forms a lip which extends over the leading edge 126 of the wing 112 and is spaced therefrom to form an annular nozzle 132. The chamber 116 has a bottom wall 134 which is sealed to the underside 136 of the wing 112. [0011] The fan 122 is arranged to provide air under high pressure into the chamber 116. The nozzle 132 is shaped and arranged to direct air from the chamber 116 over the upper surface 124 of the wing 112. The height of the nozzle 132 is such that air escaping therefrom forms a boundary layer of about 25 mm on the upper surface 124 of the wing 112.

[0012] As the air under pressure passes over the wing from the leading edge to the trailing it forms a boundary layer. For the reasons set out above this causes lift to move the aircraft vertically off the ground.

[0013] Reference is now made to Figures 2, 3, 4 and 5. Here is shown an aircraft 200 comprising a fuselage 202 including a large cabin, generally rectangular cambered wings 206, a tail plane 208 having a control rudder at its rear end and canard wings 210. A propeller 212 driven by a propulsion engine indicated at 214 is provided at the forward end of the fuselage 202 to propel the aircraft 200 in horizontal flight. A pair of control ailerons 216 are provided at the tips 218 of the wings 206 and control elevators 220 are provided at the trailing ends 222 of the wings 206. The upper surfaces 224 of the wings 206 sweep downwardly from the their roots 226 to their tips 218. Reinforcing undersides 220 are provided for the wings 210 which connect with the fuselage below the upper surfaces of the wings 206.

[0014] About midway along the length of the aircraft 200 there is an air feed chamber 228 containing a counter rotating fan 230. A drive system for the fan 230 is diagrammatically shown at 232. This may be a turbo-shaft or a clutch and gearbox system driven by the propulsion engine 214. [0015] Ports 240 are provided opening into the lower portion of the air feed chamber 214 through which air can be drawn in by the fan 230. Above the fan 230 is a pressure chamber 242 which extends adjacent the roots 226 of the wings 206 and which has inwardly converging sides 244. The upper ends of the sides 244 are sealed relative to the roots 226 of tile wings 206. A cap member 246 covers the open upper end of the pressure chamber 242. The cap member 246 has side extension pieces 248 (best shown in Figure 4) which extend a small distance over the root sections 226 of the wings 206. These extension pieces 248 and the upper part of the root sections 226 to form nozzles 250 that are capable of discharging streams of air from the pressure chamber 242 over the upper surfaces 244 of the wings 206 to form boundary layers of not more than 25mm height. As mentioned above the boundary layers cause lift which raises the aircraft. When the airplane 200 is off the ground or a predetermined height off the ground, the propeller 212 is rotated to cause forward movement of the airplane. Once the velocity of forward movement is adequate, the air flow over the upper surfaces 244 of the wing 206 will serve to provide lift and the aircraft 200 will fly in conventional manner.

[0016] The ailerons 216 serve to reinforce the boundary layer originating from the leading edge 252 of the wing 206 during horizonal flight to generate and sustain lift along the entire wing.

[0017] The cap member 246 is capable of moving relative to the fuselage 202 so that the size of the discharge ports of the nozzles 250 can be varied as desired.

[0018] The elevators and the canard wing 210 on the front of the aircraft are provided to alter the angle of attack of the wing 206 in horizontal flight to accommodate various flight conditions. The canard wing 210 also serves to assist in the transformation from vertical to horizontal flight modes.

[0019] Reference is now made to Figures 6 and 7 wherein is shown a larger aircraft 310. The aircraft 310 has a fuselage 312 with overhead wings 314 similar to although larger than the wings 206. The wings 314 have ailerons 316 and elevators 318. Canard wings 320 are provided at the forward end of the fuselage 312 and a tail plane 322 at the rear end of the fuselage 312. A pair of turbo fan engines 324 are carried below the wings 314 to provide propulsion during horizontal flight. Two or more turbo-fan engines 326 serve to deliver air under pressure to a wide delivery air pressure chamber 328 which extends along the length of the fuselage 312 above the cabin area 330. The upper part of the delivery air chamber 328 has an elongated outlet port 334. A cap member 332, similar to the cap member 236, covers the outlet port 330. The cap member 332 provides nozzles 334 and 336 to direct streams of air on to the upper surfaces 336 of the wings 312 to form boundary layers as described above. Consequently there will be lift that will raise the aircraft vertically off the ground. The turbo fan engines 324 will provide propulsion and as soon as there is adequate air flow from the leading edges of the wings 314 due to forward movement of the aircraft, the aircraft will now operate in conventional manner.

[0020] In a further modification of the invention as shown in Figure 8 there is shown a wing 410 having a leading edge 412 and a trailing edge 414 in which there are elevator flaps 416 in the usual way. The leading edge 412 comprises a member 418 that is a continuation of the underside 420 of the wing 410 and which sweeps over the front of the wing 410. The member 418 defines a pressure chamber 422 extending along the major part of, or indeed the entire, leading edge 412 of the wing. The end portion of the member 418 forms a lip 420 that lies over the front part of the upper surface 424 of the wing 410 to define a delivery nozzle 426 extending over the same length of the chamber 422. The front part 428 of the upper surface 424 which extends a small way into the discharge chamber 422 is shaped to form with the member 418 a bell mouthed entry port 430 to' the nozzle 426. Air under considerable pressure is delivered to the pressure chamber 422 by any convenient means and is discharged therefrom through the nozzle 426 in a narrow stream to form a boundary layer which causes lift to raise the aircraft off the ground and to maintain it in a raised position until the propulsion engines move the aircraft forwardly until air passing over the wing provides lift. Once the wing provides lift due to forward movement as a result of its passage through the air, the air feed to the delivery air chamber 422 can be disconnected. However if desired air may continue to be delivered through the nozzle 426 to improve lift.

[0021] Control of the lifting force can be provided by means of low vertical spoilers 432 slightly downstream of the nozzle 426.. Control is also provided by the flaps 416.

[0022] Referring now to Figure 9 there is shown a wing 510 which is generally similar to the wing 410 having flaps 512 at its trailing edge 514. This wing 510 has the pressure chamber contained in a housing 516 which is slidably mounted in the leading edge 518 of the wing 510. The housing 516 is slightly curved as is the wing 510 adjacent the leading edge 518. Thus when the housing 516 is moved forwardly it increases the chord depth of the wing 510. The increase in chord depth is supplemented by the lowered flaps 512. This increases the lifting capacity of the wing 510 for a high performance aircraft. [0023] Reference is now made to Figures 10 and 11 wherein is shown a personal commuter aircraft 610. The aircraft 610 comprises a fuselage 612 which includes a cabin 614 and which is mounted on skids 616. Between the cabin 614 and the skids 616 are two main housings 618 and 620. The housing 618 contains a generator and fuel cells (both not shown). The housing 620 is a fuel storage tank.

[0024] Above the fuselage 612 is an annular wing 622 the upper surface 624 of which is cambered. A large housing 626 carries the wing 622. The lower portion of the housing comprises an inlet space 628 having inlet ports 630. Above the space 628 is a fan 632 that draws air into the space 628 and delivers it under substantial pressure into the space thereabove which constitutes a pressure chamber 634. The pressure chamber 634 is closed off by the wing 622 and has an outlet port 636 which is constituted by the central portion of the annular wing 622. A cap member 638, similar to the cap member 236, covers the outlet port 636. The cap member 638 has a surrounding flange or lip 640 which is spaced from and overlies the inner portion or leading edge of the upper surface 624 of the wing 622 to provide a circular nozzle 644.

[0025] Above the cap member 638 is a fan drive motor 646 which is connected by a vertical shaft 648 to the fan 632. The shaft 648 continues beyond the fan 632 to a universal ball and socket joint 650 incorporating a thrust bearing (not shown). A control rod (not shown) is connected to the housing 626 to cause it, and with it the wing 622, to tilt about the joint 650.

[0026] At its periphery, the wing 622 has ailerons 652. A large vertical rudder 654 is provided connected to the wing 622 and the housing of the fan motor 646. [0027] In use the generator is actuated and conveys electric power to the fan motor 646 actuating the fan 632, The fan 632 draws air into the space 628 and then compresses the air and delivers it into the pressure chamber 634. The compressed air is discharged by the nozzle 644 which directs streams of air on to the upper surfaces 624 of the wing 622 to form a boundary layer as described above. Consequently there will be lift that will raise the aircraft vertically off the ground. Propulsion of the aircraft 610 is achieved by tilting the entire wing 622 on the universal joint.

[0028] Reference is now made to Figure 12 which shows in section a modified wing 710 having ailerons 712 as described above. As in previously described embodiments, the wing 710 is mounted on a housing 714 containing a fan 716 which draws air into the housing 714 through openings 718 in the base 720 of the housing 714 and delivers substantial volumes of air under pressure into a pressure chamber 722 thereabove. The chamber 722 has a central outlet port 724 closed off by a cap member 726 which is provided with a peripheral lip 728 that over lies the leading edge portion 730 of the upper surface 732 of the wing 710 to form a main nozzle 734.

[0029] A number of radial conduits 736 extend from the pressure chamber 722 below the wing 710. The conduits 736 open into an annular manifold 738 about half way along the width of the wing 710 and below the upper surface 732 of the wing 710. The manifold 738 has an outlet shaped to form an outer nozzle 740.

[0030] In use, the fan 716 provides a high volume high pressure air to the pressure chamber 722. A stream of air is discharged from the main nozzle 734 to form a boundary layer over the upper surface of the inner portion 740 of wing 710. At the same time air under pressure is fed to the annular manifold 738 and the outer nozzle 740 discharges a stream of air over the upper surface of the outer portion 738 of the wing 710 to form a boundary layer thereon. Consequently lift is provided to lift the aircraft of which the wing 710 is a part.

[0031] This arrangement may with advantage be provided where the width of the wing is large.

[0032] Reference is now made to Figure 13. There is shown an aircraft control surface 810 forming part of an aircraft of the invention. This control surface 810 may be in the form of (i) an elevator in the rear of the wings of the aircraft to control the fore and aft pitching moment; (ii) in the control surfaces in the extremities of the wing to control rolling moment; and (iii) in the tailplane rudder to control the yawing moment.

[0033] The control surface 810 has a leading edge member 812 which runs along the whole or a substantial portion of the leading edge 814 of the control surface 810 and partially envelopes both sides of the control surface. The interior 816 of the leading edge member 812 will receive air under pressure from a source of air pressure (such as described above) to form a pressure chamber. The leading edge member 812 comprises a "U"-shaped part having upper and lower arms 820 and 822. At the ends of the upper and lower arms 820 and 822 are respectively upper and lower extension flaps 824 and 826 which are respectively pivotally connected thereto. Biassing means (not shown) such as springs are provided to bias each flap 824 and 826 from (a) an "aligned position" where it is aligned with the arm to which it is connected to (b) an "inner position" that will be described below. Stop means (also not shown) limit the flaps from moving closer to the control surface 810 than the inner position. [0034] When the control surface is in a neutral position for normal forward flight

(as shown in dotted lines in Figures 13 and 14), the flaps 824 and 826 are inwardly biassed to have their free ends 828 and 830 engaging and sealing respectively against the upper and lower surfaces 832 and 834 of the control surface 810. When the control surface 810 is pivoted from the neutral position into an off neutral position so that its trailing edge 836 extends downwardly relative to leading edge 814 so that the upper surface 832 of the control surface 810 provides a downwardly sloping surface. In this position the under surface 834 of the control surface 810 will engage and move the lower flap 826 into alignment with the lower arm 822. In this position the remote edge of the lower flap 826 will seal against the under surface 834 of the control surface 810.

The control surface 810 will also have moved downwardly relative to the upper flap 824. Consequently the upper flap 824 will be moved downwardly into its inner position (as defined by the stop means) in which the remote edge 826 of the upper flap 824 will be spaced from the upper surface 828 of the control surface 810 and will form a nozzle 838 therewith. This nozzle 838 has the characteristics of the nozzles described above. Air under pressure is discharged from the nozzle 838 in a narrow stream to cause "lift" as discussed above to move the surface 810 in that direction. Where the control surface 810 is an aileron this can be used when the aircraft is landing vertically and the aircraft is in the "tail down" position. The lift mentioned above returns the aircraft to the horizontal disposition so that landing can take place.

[0035] As shown in Figure 14, the control surface 810 and can be moved upwardly from the neutral position to an off neutral position for the purpose of landing. When so moved, the upper surface 832 of the control surface will engage and move the upper flap 826 into the aligned position. Further the remote edge 828 of the flap 824 will seal against the upper surface 832 against the upper surface 836. The lower flap 826 being unrestrained by the control surface will be moved by the biassing means into its inner position. The free end 830 of the lower flap 826 will now form a nozzle 842 similar to the nozzle 838 with the under surface 834 of the control surface 810. Air under pressure is discharged from the nozzle 842 in a narrow stream to cause "lift" as discussed above to move the surface 810 in that direction. Where the control surface 810 is an aileron this can be used when the aircraft is landing vertically and the aircraft is in the "nose down" position. The lift mentioned above lifts the tail to return the aircraft to the horizontal disposition so that landing can take place.

[0036] It will be understood that when the control surface 810 is a rudder, and is moved from the neutral position, the "lift" will tend to move the rudder in the direction of movement of the control surface 810.

[0037] When the control surface is formed in an aileron the leading edge member may .be formed as part of the aileron.

[0038] Reference is now made to Figure 15. Here there is shown an aircraft 910 having a fuselage 912 and wings 914 with downwardly sloping upper surfaces. At the upper part of and extending longitudinally of the fuselage 912 there is a housing or container 916. Within the container 916 there is a fan 918 having a shaft which extends parallel to the axis of the fuselage. Suitable drive means (not shown) such as gas turbine engine or electric motor means driven by the propulsion means of the aircraft are provided to rotate the fan 916. The fan delivers air under pressure to a pressure chamber located at the root of the wing and having a delivery nozzle. The delivery nozzle is arranged to deliver a narrow layer of air on to a substantial portion of the upper surface of the wing. [0039] Ahead of the container 916 is an air feed chamber 922 having a transverse inlet opening 924 in the fuselage 912. Reinforcing rods extend between the front and rear edges 926 and 928 of the chamber 922. The fan draws air from the air feed chamber 922 and discharges it to the pressure chamber. A moveable envelope member 930 is provided movable between a covering position and an air feed position.

In the air feed position the envelope member is moved from the opening 924 to permit air to be drawn into the air feed chamber 922. In the covering position the envelope member covers the opening 924 to form a substantial continuation of the skin of the fuselage thereby reducing drag on the aircraft when in forward flight.

[0040] Reference is now made to Figures 16, 17 and 18 wherein is shown a wing 950 forming part of a further aircraft having a fuselage 952 to which the wing is attached at its root 954. An air pressure chamber 956 is placed at the root of the wing extending over substantially the entire length of the root. A lip 958 is provided extending above the chamber 954 and overlying the inner edge of the upper surface of the wing to form a delivery nozzle 960 that is able to emit a layer of air which covers the upper surface and has a thickness of no more 25 mm. At the trailing edge 962 of the wing 950 is a flap 964 controlling the aspect of the aircraft as is known to those skilled in the art. At side edge 966 of the wing 950 is a flap 968 for controlling lift of the aircraft when air from the pressure chamber 956 is blowing over the upper surface of the wing.

[0041] As will have been seen that all the nozzles above described (except for the outer nozzle 736) comprises a part overlying the upper surface of the wing and spaced therefrom so as to eject a stream of air which is able to form a boundary layer of not more than 25 mm in height. Typically the outlet from the nozzles are between about 15 mm and 40 mm in height with a preferred height of 25 mm. The length of the overlie and hence the length of the nozzle is preferably about 200 mm to 400 mm and most desirably about 300 mm.

[0042] The ejected from the nozzles may be at about eight to ninety knots indeed more being up to about two hundred knots. This figure my vary for various reasons.

[0043] The invention is not limited to the precise constructional details hereinbefore described and illustrated in the drawings. For example downwardly directed turbo jet engines may be provided to give additional lift. The nozzles may be of fixed construction.

[0044] It will be understood that various features shown in one or more of the embodiments may be provided for other embodiments which as described do not embody these features.