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Title:
AIRCRAFT
Document Type and Number:
WIPO Patent Application WO/2003/035470
Kind Code:
A1
Abstract:
An aircraft (10) is provided having a rotary lifting system (26) including vanes (36) supported thereon which are movable between a deployed position in which the vanes (36) provide lift to the aircraft (10) when rotated and an undeployed position in which the rotary lifting system (26) is generally in the shape of an airfoil so as to provide lift when propelled in a forward direction. A forward drive system (54) is included to generate forward thrust to propel the housing in the forward direction. The airfoil shape of the rotary lifting system (26) permits the wings (24) of conventional aircraft to be reduced or even eliminated to minimize excessive drag from wings which are larger than necessary for normal cruise on conventional aircraft. Furthermore, the engines(54) of the forward drive system are not required to be any larger or more powerful than appropriate for sustaining flight at normal cruise height.

Inventors:
Lamont, John S. (30th Floor - 360 Main Street, Winnipeg, Manitoba R3C 4G8, CA)
Application Number:
PCT/CA2002/001571
Publication Date:
May 01, 2003
Filing Date:
October 17, 2002
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
Lamont, John S. (30th Floor - 360 Main Street, Winnipeg, Manitoba R3C 4G8, CA)
International Classes:
B64C27/24; B64C29/00; B64C39/06; (IPC1-7): B64C39/00; B64C29/00
Foreign References:
US5240204A
DE1288924B
FR1129038A
EP0652154A1
Other References:
None
Attorney, Agent or Firm:
ADE & COMPANY (1700-360 Main Street, Winnipeg, Manitoba R3C 3Z3, CA)
Download PDF:
Claims:
CLAIMS :
1. An aircraft comprising: a housing; a rotary lifting system including vanes supported thereon which are movable between a deployed position in which the vanes provide lift to the housing when the rotary lifting system is rotated and an deployed position in which the rotary lifting system is generally in the shape of an airfoil so as to provide lift to the housing when the housing is propelled in a forward direction; and a forward drive system mounted on the housing arranged to generate forward thrust to propel the housing in the forward direction.
2. The aircraft according to Claim 1 wherein the rotary lifting system includes an airfoil shaped rotating body supporting the vanes thereon and wherein the vanes are flush with an upper surface of the rotating body in the deployed position.
3. The aircraft according to Claim 2 wherein the vanes each include a lifting surface which lies transversely to a respective opening in the upper surface of the rotating body which supports the vane therein.
4. The aircraft according to Claim 1 wherein the vanes are supported on a pair of rotary elements which are arranged to rotate in opposite directions, at spaced positions on respective shafts, about a common upright axis which is adjacent a centre of gravity of the housing.
5. The aircraft according to Claim 4 wherein both rotary elements are generally in the shape of an airfoil in an deployed position of the vanes.
6. The aircraft according to Claim 4 wherein a secondary one of the rotary elements is arranged to be nested within a main one of the rotary elements in an deployed position of the vanes.
7. The aircraft according to Claim 1 wherein the vanes are displaced between the respective deployed and deployed positions by electric motors coupled to the vanes by suitable gearing.
8. The aircraft according to Claim 7 wherein at least some of the electric motors are responsive to a remote control activation signal for displacing the vanes between the deployed and deployed positions.
9. The aircraft according to Claim 1 wherein there is provided a pair of wings extending laterally outwardly from opposing sides of the housing which are arranged to provide lift to the housing when the housing is propelled in the forward direction, the wings being positioned substantially forward of the rotary lifting system.
10. The aircraft according to Claim 9 wherein the wings are positioned forwardly of a centre of gravity of the housing and wherein there is provided a horizontal stabiliser positioned rearwardly of the centre of gravity of the housing.
11. The aircraft according to Claim 10 wherein there is provided a mechanical drive mechanism coupled to the forward drive system and being arranged to selectively drive rotation of the rotary lifting system, the mechanical drive mechanism being driven by the forward thrust of the forward drive system.
12. The aircraft according to Claim 1 wherein the mechanical drive mechanism comprises a turbine arrangement mounted in communication with exhaust from the forward drive system and being arranged to be driven by the forward thrust of the forward drive system, the turbine arrangement being arranged to drive the rotary lifting system.
13. The aircraft according to Claim 1 wherein the vanes are supported on a pair of rotary elements spaced one above the another, the vanes being movable into a parachuting position in which the vanes in one of the rotary elements are deployed and the vanes in the other rotary element are undeployed.
14. The aircraft according to Claim 1 wherein the rotary lifting system is mounted externally above the housing.
15. The aircraft according to Claim 1 wherein the vanes are pivotally supported for pivotal movement between various vane angles between the deployed and deployed positions.
16. The aircraft according to Claim 1 wherein the forward drive system includes a directional control system arranged to redirect the forward thrust of the forward drive mechanism.
17. The aircraft according to Claim 16 wherein the directional control system comprises a series of adjustable baffles supported in communication with exhaust from the forward drive system.
18. The aircraft according to Claim 17 wherein there is provided at least one horizontally oriented baffle and at least one vertically oriented baffle.
19. The aircraft according to Claim 1 wherein there is provided a thrust reversing mechanism coupled to the forward drive system arranged to divert a portion of the forward thrust to rearward thrust acting on the housing in a direction opposite to the forward direction.
20. The aircraft according to Claim 19 wherein the thrust reversing mechanism is arranged to balance the rearward thrust with the forward thrust generated by the forward drive system for vertical takeoff and landing.
Description:
AIRCRAFT FIELD OF THE INVENTION The present invention relates to an aircraft and more particularly to an aircraft employing a rotary lifting system for take off with little or no forward ground speed.

BACKGROUND Conventional aircraft rely on forward thrusters and wing design to generate the required lift for take-off and to maintain cruising altitude. These aircraft however require more powerful engines and wing sizes of greater thickness and size for landing and take-off than are required to maintain the aircraft's speed and altitude at normal cruise height. The engines are thus heavier and the wings create more drag than is necessary to sustain the aircraft at cruising altitudes. In addition, conventional aircraft require very strong and relatively heavy landing gear in order to sustain the forces involved in landing the aircraft at their required landing speeds. The excessive weight of these components reduces load carrying capacity and efficiency during normal flight of the aircraft.

Various known modified aircraft have been arranged for vertical take-off to avoid the problems normally associated with taking off and landing of conventional aircraft. These modified aircraft generally use separate engines for vertical and horizontal thrust or require complex mechanisms to generate both the vertical and horizontal thrust and maintain directional stability. These known designs are thus generally complex and costly and result in reduced efficiency and economy.

SUMMARY According one aspect of the present invention there is provided an aircraft comprising: a housing; a rotary lifting system including vanes supported thereon which are movable between a deployed position in which the vanes provide lift to the housing when the rotary lifting system is rotated and an deployed position in which the rotary lifting system is generally in the shape of an airfoil so as to provide lift to the housing when the housing is propelled in a forward direction; and a forward drive system mounted on the housing arranged to generate forward thrust to propel the housing in the forward direction.

In the present invention the forward drive system directly provides forward thrust for efficient normal cruising altitude flight, while the vanes of the rotary lifting system coupled thereto provide the necessary lift at speeds less than stall speed, as required for take-off and landing for example. In this arrangement the initial power or forward thrust of the forward drive system can be devoted entirely to providing power for lift off using the rotary lifting system and thus is not immediately employed to build up air speed and overcome friction for take-off.

The engines of the forward drive system are thus not required to be any larger or more powerful than appropriate for sustaining flight at normal cruise height. The airfoil shape of the rotary lifting system permits the wings of conventional aircraft to be reduced or even eliminated to minimize excessive drag from wings which are larger than necessary for normal cruise on conventional aircraft. The rotary lifting system may further be used when landing the aircraft to permit landing at very slow or even zero speeds, eliminating the need for very strong and heavy landing gear, resulting in a reduction of weight and a more efficient aircraft. The aircraft according to this design may thus be considerably more economical in fuel consumption than conventional aircraft currently in use.

The rotary lifting system preferably includes an airfoil shaped rotating body supporting the vanes thereon in which the vanes are flush with an upper surface of the rotating body in the deployed position.

The vanes each preferably include a lifting surface which lies transversely to a respective opening in the upper surface of the rotating body which supports the vane therein.

The vanes may be supported on a pair of rotary elements which are arranged to rotate in opposite directions on respective shafts, at spaced positions, about a common upright axis which is adjacent a centre of gravity of the housing.

In one arrangement, both rotary elements may be generally in the shape of an airfoil in an deployed position of the vanes.

Alternatively, a secondary one of the rotary elements may be arranged to be nested within a main one of the rotary elements in an deployed position of the vanes.

In a preferred embodiment, the vanes are displaced between the respective deployed and deployed positions by electric motors coupled to the vanes by suitable gearing. At least some of the electric motors are preferably responsive to a remote control activation signal for displacing the vanes between the deployed and deployed positions.

There may be provided a pair of wings extending laterally outwardly from opposing sides of the housing which are arranged to provide lift to the housing when the housing is propelled in the forward direction, the wings being positioned substantially forward of the rotary lifting system.

The wings of the aircraft are preferably positioned forwardly of a centre of gravity of the housing. The wings are thus substantially balanced with the horizontal stabiliser positioned rearwardly of the centre of gravity of the housing at the rear of the aircraft.

There may be provided a mechanical drive mechanism coupled to the forward drive system and being arranged to selectively drive rotation of the rotary lifting system, the mechanical drive mechanism being driven by the forward thrust of the forward drive system.

The mechanical drive mechanism preferably comprises a turbine arrangement mounted in communication with exhaust from the forward drive system, and arranged to be driven by the forward thrust of the forward drive system. Furthermore, the turbine arrangement is preferably arranged to drive the rotary lifting system.

When the vanes are supported on a pair of rotary elements spaced one above the another, the vanes are preferably movable into a parachuting position in which the vanes in one of the rotary elements are deployed and the vanes in the other rotary element are undeployed.

The rotary lifting system is preferably mounted externally above the housing free from obstruction by the wings.

The vanes are preferably pivotally supported for pivotal movement between various vane angles between the deployed and deployed positions.

The forward drive system may include a directional control system arranged to redirect the forward thrust of the forward drive mechanism, the directional control system comprising a series of adjustable baffles supported in communication with exhaust from the forward drive system. Preferably at least one horizontally oriented baffle and at least one vertically oriented baffle are included.

There may be provided a thrust reversing mechanism coupled to the forward drive system, arranged to divert a portion of the forward thrust to rearward thrust acting on the housing in a direction opposite to the forward direction.

The thrust reversing mechanism is preferably arranged to balance the rearward thrust with the forward thrust generated by the forward drive system for vertical take-off and landing.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, which illustrate exemplary embodiments of the present invention: Figure 1 is a side elevational view of a first embodiment of the aircraft.

Figures 2 and 3 are respective front elevational and top plan views of the aircraft according to Figure 1.

Figure 4 is a cross sectional view of one of the jet engines.

Figure 5 is a sectional view of the shafts supporting the rotary elements on the housing.

Figure 6 is an isometric view of a pair of vanes of the rotary lifting system of the aircraft according to Figure 1.

Figure 7 is a front elevational view of a second embodiment of the aircraft.

DETAILED DESCRIPTION Referring to the accompanying figures there is illustrated an aircraft generally indicated by reference numeral 10. The aircraft 10 is particularly suited for vertical takeoff and landing as well as for cruising in a manner which is typically more efficient than conventional aircraft.

The aircraft 10 includes a housing 12 similar to the fuselage of conventional aircraft, being elongate and generally tubular. The housing 12 includes a conical nose portion at a front end 14 for positioning the cockpit therein. At a rear end 16 of the housing spaced rearwardly of a centre of gravity of the housing, stabilisers including a vertical tail rudder 18 and a horizontal elevator 20 are provided with appropriate control surfaces thereon for controlling flight of the aircraft during normal cruising similar to conventional aircraft. The housing 12 also includes landing gear 22 on a bottom side thereof which is smaller and lighter than conventional aircraft, so as to be suitable for vertical takeoff and landing.

A pair of wings 24 are provided which extend laterally outwardly from opposing sides of the housing 12. The wings are located on the housing 12 adjacent a bottom side thereof forwardly of a center of gravity of the housing.

The wings have a conventional airfoil shaped cross section suitable for being propelled in a forward direction with the housing, and include appropriate control surfaces for controlling the flight of the aircraft.

A rotary lifting system 26 is mounted externally above the housing, above a center of gravity of the housing for providing lift to the housing when rotated. The wings 24 are positioned substantially forward of the rotary lifting system so that a majority of the wing surfaces are positioned forwardly of the rotary lifting system and downdraft extending directly below the rotary lifting system when the system is rotated. Accordingly the majority, or substantially the entire, rotary lifting system is clear of obstruction by the wings therebelow in operation. Due to the lifting force provided by the rotary lifting system, the wings 24 are considerably smaller than those provided on conventional winged jet aircraft.

The system 26 includes a main rotary element 28 in the form of a disc supported above the housing, extending generally horizontally in the direction of flight of the aircraft. The main rotary element 28 is arranged to rotate about a central vertical axis extending through the center of gravity of the aircraft on a first shaft 30 extending upwardly from the housing and supporting the main rotary element on a top end thereof. The main rotary element 28 includes a domed upper surface 32 which is generally in the shape of an airfoil. A circular recess 34 is provided in a bottom side of the main rotary element 28.

The main rotary element includes a plurality of vanes 36 in the upper surface 32 thereof spaced circumferentially about the disc. Each vane 36 is a somewhat triangular or wedge shaped panel which is pivotally mounted at an apex at an inner end 38 on a central hub 40 of the rotary element while being pivotally mounted at an outer end 42 adjacent a periphery 44 of the rotary element. Each vane 36 is pivotal about a respective radial axis of the rotary element extending through a respective inner end 38 and respective outer end 42 thereof.

Each vane 36 is pivotal between an deployed position lying flush with the domed upper surface 32 as shown in Figure 1 in which the main rotary element 28 is generally in the shape of an airfoil with the upper surface 32 being smooth, and a deployed position as illustrated in Figure 4 in which the panel of the vane 36 extends transversely to the domed upper surface 32 at one of various selected angles in relation to the domed upper surface. In the deployed position of the vanes 36 lift is provided to the housing when the main rotary element 28 is rotated.

The main rotary element has a body, the upper surface 32 of which defines the shape of an airfoil. The body includes openings in the upper surface 32 which receive the vanes 36 respectively, the openings extending vertically through the body to a bottom surface thereof to permit passage of air therethrough in operation. In the deployed position, the openings are closed by the respective vanes as the vanes lie flush with the upper surface. In the deployed position, the vanes project beyond the upper surface 32 and include respective lifting surfaces which lie transversely to the plane of the openings in the upper surface 32.

The rotary lifting system 26 also includes a secondary rotary element 46. The secondary rotary element 46 also comprises a generally disc like shape having vanes 36 housed in respective openings extending through the body of the secondary rotary element as described above with regard to the main rotary element 28.

In the first embodiment as shown in Figures 1 through 6, the upper surface of the secondary rotary element 46 is generally flat so that the secondary rotary element 46 is suitably arranged to fit within the circular recess 34 when the vanes 36 of both the main and secondary rotary elements are in the deployed position.

The vanes 36 of the secondary rotary element 46 are arranged to be flush with a bottom side 48 of the secondary rotary element when in the deployed position so as to define a more ideal air foil shape when the main and secondary rotary elements are nested one within the other in an deployed position thereof as shown in Figure 1. When deployed, the vanes of the secondary rotary element each include a respective lifting surface which, in a deployed position, projects downwardly beyond the bottom side 48 of the secondary rotary element, transversely to the plane of the respective opening in the bottom side 48 which houses the vane therein.

The secondary rotary element 46 is supported on a second shaft 50 which is concentric about the first shaft 30 supporting the main rotary element 28 thereon. The first and second shafts 30 and 50 are thus supported rotatably on the housing 12 with the secondary rotary element 46 being supported on a top side of the second shaft, and the first shaft extending concentrically through both the second shaft and the secondary rotary element 46. Both the main and secondary rotary elements are thus arranged to rotate about the common vertical axis extending through the center of gravity of the housing in opposite directions from one another. The first shaft is slidable in a longitudinal direction of the shaft in relation to the second shaft for movement of the rotary elements between respective deployed and deployed positions thereof.

Rotation of the rotary elements is controlled by a mechanical drive mechanism 52 in the form of gear boxes which are coupled to the first and second shafts respectively in a manner to suitably control rotation thereof in opposite directions. The mechanical drive mechanism 52 includes a neutral position in which the first and second shafts are stationary for use of the discs as an airfoil in the deployed position thereof.

The mechanical drive mechanism 52 is powered by a pair of jet engines 54 which are supported on the housing laterally spaced apart on opposing sides of the first and second shafts and on opposing sides of the housing near the center of gravity thereof. The jet engines 54 provide forward thrust to the housing to provide lift to the housing using the airfoil surfaces of the main and secondary rotary elements and the wings 24. A turbine 55 within the exhaust flow of each jet engine 54 is coupled to the mechanical drive mechanism for driving the mechanical drive mechanism in response to rotation of the turbine within the exhaust flow of the jet engines.

The mechanical drive mechanism is arranged to selectively engage the turbines with the rotary lifting mechanism when displaced between respective neutral and engaged positions thereof. When engaged the mechanical drive mechanism provides a direct coupling between the jet engines 54 and rotation of the main and secondary rotary elements for providing lift using the vanes 36 of the rotary elements.

Turning now to Figure 5, the first and second shafts, as well as operation of the vanes between the deployed and deployed positions is shown in further detail. Each vane 36 supports a gear 70 at the inner end 38 thereof.

The gears 70 of each rotary element are connected for meshing in communication with a common ring gear 72 housed within the central core 40 of each rotary element. The ring gear 72 comprises an annular member having a toothed upper surface for engagement with the respective gears 70 of the vanes.

Rotation of the ring gear about the respective shaft in relation to the respective rotary element causes all of the gears 70 of that rotary element to be slightly rotated so as to cause the vanes to rotate together between the respective deployed and deployed positions. Rotation of the ring gear relative to the respective rotary element is accomplished by a plurality of electric motors 74 at three or more circumferentially spaced positions about the core of the rotary element. Suitable gearing couples the electric motors to the ring gears for rotating the ring gear when the electrical motors operate together.

In the main rotary element 28, the electric motors 74 are powered by a plurality of circumferentially spaced batteries 76 also housed within the central core 40. A receiver 78 is coupled to the motors 74 of the main rotary element for receiving a transmitted control signal from a remote activation source so that the vanes are rotated to either the deployed or deployed positions as well as various relative angles therebetween in response to receipt of the control signal from a suitable transmitter on the housing of the aircraft. When in the deployed position, with the secondary rotary element recessed within the main rotary element, suitable electrical contacts are provided between the rotary elements for recharging the batteries 76 of the main rotary element using power from the aircraft.

The secondary rotary element 46 uses rolling electrical contacts 80 rotatably coupled between the housing and the electric motors 74 housed within the core thereof in order to provide continuous power and respective control signals to the electric motors 74 of the secondary rotary element 46.

The second shaft 50 mounting the secondary rotary element 46 thereon is tubular in shape for receiving the first shaft 30 extending therethrough.

Suitable bearings 82 are provided for fixing the radial and axial position of the second shaft relative to the housing while permitting the second shaft to remain rotatable about its respective longitudinal axis relative to the housing. Additional bearings 84 are provided between the inner surface of the second shaft and the outer surface of the first shaft extending therethrough. The bearings 84 permit the shafts to remain rotatable relative to one another while additionally supporting the first shaft for longitudinal sliding movement relative to the second shaft.

A hydraulic piston cylinder 86 is provided for raising and lowering the main rotary element in relation to the secondary rotary element. The piston cylinder 86 is fixed at a cylinder end on the housing while being rotatably coupled to the first shaft 30 at a cylinder end by suitable bearings 88 so as not to restrict rotation of the first shaft relative to the piston cylinder 86 and the housing to which it is mounted.

Control signals for the electric motors 74 of the main rotary element 28 and the secondary rotary element 46 respectively are operable independently of one another to permit vanes of only one of the rotary elements to be deployed at a time if desired. This may be advantageous to the stall characteristics of the aircraft in circumstances where the main rotary element 28 is raised with the vanes deployed so as to close the openings in the rotary element while the secondary rotary element 46 has vanes which are either partly or wholly deployed so as to permit air to be communicated through the openings in the secondary rotary element 46 housing the vanes therein. The rotary elements in this instance act as parachutes located above the center of gravity of the aircraft for slowing the rate of descent of the aircraft even under loss of power conditions.

A third jet engine 56 can be mounted at the rear end 16 of the housing to provide additional forward thrust. The third jet engine 56 includes a thrust reverser mechanism 58 arranged to divert a portion of the forward thrust of the jet engines to rearward thrust to balance thrust acting on the housing during vertical takeoff and landing. The pair of jet engines 54 mounted adjacent the mechanical drive mechanism 52 may also be provided with thrust reverser mechanisms 58 as required. A thrust reverser mechanism 58 is shown deployed in solid line in Figure 4, and is shown deployed in dotted line in that same figure.

Each of the jet engines 54 and 56 includes a direction control 60 arranged to direct the exhaust of the engines to assist the manoeuvrability of the aircraft at the slower speeds involved in landing and take-off. The direction control preferably comprises a series of vertical and horizontal baffles located in the exhaust flow of the jet engines.

In use the aircraft 10 is permitted to takeoff vertically by engaging the thrust reversers of the jet engines 54 at the sides of the housing or 56 at the rear of the housing and by engaging the mechanical drive mechanism so that thrust from the jet engines 54 drives rotation of the main and secondary rotary elements. With the vanes 36 in the deployed position, the jet engines 54 provide sufficient power to the rotary lifting system that the vanes lift the housing 12.

Once the aircraft 10 has become elevated, the thrust reversers may be deployed so that sufficient forward speed can be accumulated until the aircraft is above its stall speed. The mechanical drive mechanism 52 may then be displaced into a neutral position to stop rotation of the first and second shafts of the rotary lifting system, permitting the main and secondary'rotary elements to be displaced into an deployed position thereof by sliding the first shaft 30 within the second shaft 50 until the secondary rotary element 46 is received within the circular recess 34 of the main rotary element 28. The airfoil shape of the rotary lifting system and the wings 24 provide sufficient lift thereafter to maintain altitude while the aircraft is propelled in the forward direction. When landing is desired, the reverse operations may be accomplished by again deploying the vanes and engaging the mechanical drive mechanism and the thrust reversers for vertical descent while the vanes 36 provide the required lift during landings.

In another embodiment as illustrated in Figure 5, both the main and secondary rotary elements may be generally of airfoil shape so that both provide lift in the deployed position of the vanes. In this instance, the vanes 36 of each rotary element are flush with a respective upper surface of that element in an deployed position thereof while being arranged to provide lift in the deployed position as in the previous embodiment. When both rotary elements are generally airfoil shaped, the wings 24 as described in the previous embodiment may not be required as the rotary lifting system provides sufficient lifting surfaces to maintain altitude at cruising speeds.

In either embodiment, the vanes 36 of the two discs are arranged to be balanced so that both rotary elements generate substantially the same rotary force for countering the rotary forces between the two to generate a net vertical lifting force at takeoff and landings.

As described above, the aircraft consists of a conventional aircraft hull with two counter-rotating circular discs mounted directly above the hull, preferably from its center of gravity under normal load conditions. The discs are attached to the hull by appropriate means and powered by axles geared to two jet engines located side by side immediately above the aircraft hull. The engines drive the circular discs to provide lift for takeoff and landing at 0 or low speeds when vanes in the circular discs are deployed.

The engines are of appropriate power sufficient to move the circular discs at a speed sufficient to provide the lift necessary for takeoff and after takeoff, to move the aircraft to a speed above its stall speed, at which point the vanes are deployed and flattened against the circular discs. The discs are then brought to a stationary position relative to the aircraft hull, the power to the discs shut off and the jet engines then diverted entirely to moving the aircraft forward.

When not directly required for lift, and to reduce air friction in flight, the lower circular disc can be elevated into the hollow under the upper circular disc, or the upper disc lowered to enclose the lower circular disc. For normal cruising flight, the vanes in the circular discs would remain deployed and the discs would remain stationary. The upper disc is somewhat airfoil shaped to contribute to the lift required for normal flight.

Since the upper circular disc is typically not an ideal airfoil, it may be desirable to have lower wings attached to the bottom of the hull. These provide space for gasoline tanks, and add lift. If the lower wings are fairly short, they do not unduly interfere with the lifting capacity of the circular discs when in operation.

Since the kind of control surfaces employed by conventional aircrafts are not sufficiently effective at the low speeds of takeoff and landing involved in this aircraft design, special provision to provide horizontal and vertical stability and control are required. These are provided by horizontal and vertical baffles located in the engines exhaust flow.

It may be desirable to have a third jet engine at the rear of the aircraft hull, and a rear rudder and elevator to provide directional controls at normal cruising speed. The third jet engine may be provided with thrust reversers, in order to moderate the aircrafts forward motion during takeoff and landing, which could eliminate the need for thrust reversers on the other jet engines 54 at the sides of the housing.

The aircraft as described herein, has the following advantages: 1. Since the initial power of the engines can be devoted entirely to providing power for lift-off and is not immediately required to build up air speed and overcome ground friction for takeoff, the engines do not require to be any larger or more powerful than appropriate for sustaining normal cruise flight ; 2. The excess drag involved in wings which are larger than necessary for normal cruise is minimised; and 3. Since the aircraft is designed to land at very slow or even zero speeds, the necessity for very strong and heavy landing gear is eliminated.

These factors mean that this design of aircraft should be considerably more economical in fuel consumption than the types of aircraft currently in use.

For civilian purposes, the aircraft 10 enjoys the advantage over other designs of not requiring the use of conventional airports for landing and take-off. Airlines using the aircraft 10 will be able to utilize their own relatively small landing pads adjacent to city centers, and thereby avoid landing fees at regular airports. This would also enable airlines utilizing the aircraft 10 to provide their customers with easy access to and from city centers, and enable their passengers to avoid the usual long drive to airports at the outskirts of the cities being served. This factor would be a distinct marketing advantage.

This design also enables airlines to make stops at locations without airports, and enables remote locations to provide for air services by building relatively inexpensive landing pads and to avoid the expense of airports with long runways.

While various embodiments of the present invention have been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.