Warplanes, especially supersonic warplanes are required to be of high performance in virtually every property: these aircraft need to be able to fly at supersonic speeds, be highly agile, carry heavy payloads and fly long distances.

A highly desired capability that has not yet been successfully integrated with the other warplane requirements is vertical take-off capability (VTO).

Vertical take-off is a significant force multiplier. Aircraft with vertical take off ability can be hidden in a large area, far from an easily discernible airfield and yet still be available for immediate operational use. VTO allows aircraft to be transported to a locale using unmodified sea vessels. VTO allows deployment of high performance aircraft in areas where only low quality airfields exist or when airfields have been destroyed due to enemy activity.

Rotary winged aircraft such as helicopters are known in the art as having VTO capability but have not been shown to be effective at high altitudes or for supersonic flights.

Only a few VTO-capable fixed wing warplanes have been developed and operationally deployed.

In the well known Harrier and variants, VTO flight is attained by redirecting thrust of a turbofan engine (in the AV-8B Harrier 1I Plus model, typically a Rolls Royce Pegasus F402-RR-408 having 9400kg of thrust) downwards using adjustable

ducts, allowing the Harrier to hover and change altitude vertically. To change from vertical flight to horizontal flight the ducts are closed and the Harrier flies in a conventional manner using the same turbofan engine. The Harrier is a subsonic aircraft and when compared to similar sized aircraft has a limited range and carries a relatively small payload. For example, a 6.7 ton AV-8B Harrier II Plus can carry only 6 ton payload (2 tons at a limited range when VTO is required) as opposed to the 8.7 ton supersonic F-16C which can carry a 10 ton payload.

The Yak-141 is a supersonic VTO-capable fixed wing aircraft. For conventional flight the Yak-141 is equipped with two turbofan lift engines (4100 kg Rybinsk RD-41) and a vectored main turbofan engine (15500 kg Soyuz R-79V-300).

Although capable of supersonic flight, the 12 ton Yak-141 has a limited range and a payload of only 2.6 tons (1 ton for VTO) when compared to similar conventional aircraft.

Although successful as niche aircraft, it is unlikely that either the Harrier design or the Yak-141 design for war planes will become ubiquitous. Since the lion's share of missions of an aircraft do not require VTO, it is ultimately preferable to compromise on VTO capability and retain other important parameters.

. It would be highly desirable to VTO capability without compromising on other parameters. It would be exceptionally desirable to be able to give vertical take-off capability to existing supersonic jet airplanes.

SUMMARY OF THE INVENTION

The above and other objectives are achieved by the method and the flight platform provided by the present invention.

The method of the present invention is based on redirecting the thrust of the already installed jet engines of an aircraft to power a turbofan. The thrust of the turbofan is directed in such a way as to lift the aircraft upwards vertically allowing VTO. Once the aircraft is in flight, the turbofan is released from the aircraft. The aircraft can then proceed with normal flight.

The flight platform of the present invention comprises a platform to which an aircraft can be connected. The platform is provided with ducts that direct the exhaust of the aircraft engines to power one or more turbofans disposed so that the thrust of the turbofans is generally downwards, lifting the aircraft and the platform upwards.

Once sufficient altitude is achieved the platform is discarded and the aircraft proceeds with normal flight.

According to the teachings of the present invention there is provided a flight platform allowing an aircraft to take off vertically comprising: a) a platform with a top surface on which the aircraft can be supported and a bottom surface; b) at least. one turbofan with an inlet in the top surface of the platform and a thrust outlet in the bottom surface of the platform, the at least one turbofan configured to be powered by gas flowing through thrust directing conduits; and c. at least one thrust directing duct, configured to direct exhaust gas produced by an engine of an aircraft supported on the top surface of the platform into the thrust directing conduits.

There is also provided according to the teachings of the present invention a method of performing a vertical take-off in an airplane comprising redirecting exhaust of jet engines of the aircraft to power at least one vertically disposed turbofan in such a way as to produce vertical thrust sufficient to lead to vertical take-off.

There is also provided according to the teachings of the present invention a method of performing a vertical take-off in an airplane comprising: a. placing an aircraft on a flight platform as described above; b. activating the engine of the aircraft so. as to produce thrust; c. using the thrust directing duct of the platform to direct exhaust gases from the aircraft engines into the thrust directing conduits so as to power the at least one turbofan of the platform ; d. using thrust produced by the at least one turbofan to perform the vertical take off.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, where: FIG. lA is a schematic depiction of a flight platform of the present invention from the side; FIG. 1B is a schematic depiction of a flight platform of the present invention from the top; FIG. 1C is a schematic depiction of a flight platform of the present invention from the bottom;

FIG. 2 is a schematic depiction of a turbofan useable in a flight platform of the present invention; and FIGS. 3A-3C are schematic depictions of the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The principles and use of the method and flight platform of the present invention are better understood with reference to the drawings and the accompanying description.

In Figures 1 is depicted a flight platform 10 of the present invention. Figure lA is a side view of flight platform 10 with an aircraft 12 attached. Figure 1B is a top view of flight platform 10. Figure I C is a bottom view of flight platform 10.

Flight platform 10 is substantially a platform 14 on which an aircraft 12 can rest. Releasable stops 16 hold aircraft 12 in association with flight platform 10 through landing gear 18. Releasable stops 16 include an explosive high-speed release mechanism 20.

Attached to platform 14 are wings 22 with flaps 24 controlled by electrical flap motors 26. Disposed in platform 14 are four turbofans 28 having an inlet 30 at the top of platform 14 and a thrust outlet 32 at the bottom of platform 14. Turbofans 28 are powered by exhaust from jet engines 34 of aircraft 12 that enters thrust directing ducts 36 and is directed through thrust directing conduits 38 (represented by dashed lines in Figures I B and 1 C) to each of turbofans 28. Thrust outlets 32 of turbofans 28 include adjustable nozzles 40 and thrust vector control vanes 42, powered by electrical motors 44 and 46 respectively. Thrust directing ducts 36 are provided with openable vents 41

powered by electrical motors 43. Excess jet engine exhaust exits conduits 38 from vents 39.

All systems are controlled by flight computer 48 that receives data from flight sensors 50 and from a flight control unit 52. Flight control unit 52 is equipped with wireless receiver 54 to receive commands from wireless pilot remote control 56, configured to translate flight commands given by a pilot to instructions understandable by flight control unit 52 and to transmit them, through wireless receiver 54 to flight control unit 52.

Thrust directing conduits 38 also direct thrust to power electricity generating turbine 56. Power from electricity generating turbine 56 is used to power electrical motors 26,43, 44 and 46. Batteries 58 provide electrical power to flight computer 48, flight sensors 50, flight control unit 52, wireless receiver 54 and the trigger of release mechanism 20.

In Figure 2 is schematically depicted a turbofan 51 useable according to the present invention. Jet engine exhaust is directed into an inlet 53 from the direction of arrow 55. The exhaust drives turbine 57 to rotate fan 59. The rotation of fan 59 produces thrust.

In order to perform vertical take off according to the method of the present invention, aircraft 12 is attached through landing gear 18 to platform 14 of a flight platform 10, a flight platform of the present invention. The pilot of aircraft 12 uses pilot remote control 56 to activate battery powered systems and perform any necessary pre-flight tests.

The pilot activates jet engines 34 of aircraft 12. Exhaust from jet engines 34 is directed by thrust directing ducts 36 into thrust directing conduits 38 powering turbofans 38 and electricity generating turbine 56. The amount of jet engine exhaust directed to turbofans 38 is adjusted by opening and closing vents 41 of thrust directing ducts 36. In such a way the thrust produced by turbofans 38 is adjusted.

When the pilot chooses to take off, the pilot uses pilot remote control 56 to transmit flight instructions to flight control unit 52 through wireless receiver 54.

Flight computer 48 receives these instructions from flight control unit 52 and flight data from flight sensors 50 in order to direct the control surfaces of platform 10 (including vents 41, adjustable nozzles 40 and thrust vector control vanes 42) in the proper fashion so as to lead to stable vertical take off, Figure 3A., Flight computer 48 continuously monitors data from flight sensors 50 and adjusts the control surfaces properly.

In a first embodiment of the method of the present invention, depicted in Figure 3B, once aircraft 12 is sufficiently high, the pilot directs flight platform 10 with aircraft 12 to fly forwards using the control surfaces. Once a sufficient forward airspeed is attained both the control surfaces of aircraft 12 and control surfaces of platform 12 (including flaps 24 of wings 22) can be used for some level of flight control. When forward airspeed and altitude is sufficient, explosive release mechanism 20 of releasable stops 16 is activated separating flight platform 10 and aircraft 12 from each other. Flight computer 48 is programmed, upon release, to use control surfaces of platform 10 to ensure that flight platform 10 does not interfere with further flight of aircraft 12.

In a second embodiment of the method of the present invention, depicted in Figure 3C, once aircraft 12 is sufficiently high, the pilot directs flight platform 10 with aircraft 12 to change the pitch of aircraft so as to direct the nose of aircraft 12 upwards. Once the pitch angle is sufficient, the thrust of jet engines 34 is increased together with the activation of explosive release mechanism 20 of releasable stops 16.

Flight platform 10 and aircraft 12 are separated from each other. Flight computer 48 is programmed, upon release, to use control surfaces of platform 10 to ensure that flight platform 10 does not interfere with further flight of aircraft 12. The second embodiment of the method of the present invention is suitable only for aircraft with exceptional thrust to weight ratios.

Although flight platform 10 depicted hereinabove has four turbofans 28 it is clear to one skilled in the art that any effective number of turbofans may be used. It can generally said that the more turbofans any flight platform of the present invention has, the more easily controllable and stable of flight the flight platform shall be.

One skilled in the art recognizes the non-aerodynamic shape of the unit made up of an aircraft attached to a flight platform of the present invention. The lack of an aerodynamic shape makes the unit seemingly difficult to control. However, one skilled in the art recognizes that the design and manufacture of a flight control computer such as 48 configured to translate simple pilot commands into complex coordinated actions of flight control surfaces is well-known and relatively easily achieved. Such flight control computers are implemented in such aerodynamically unstable aircraft as the F- 117 or the F-18 deployed by the armed forces of the United States.

The flight pattern of a flight platform of the present invention is relatively monotonous, involving vertical flight to a certain altitude, possible limited horizontal flight followed by release of the flight platform. Thus in one embodiment, a flight control computer is programmed for fully automatic flight. However, it is clear that fully automatic flight is rarely a desired option under operational conditions. It is preferred that a pilot have control of such flight decisions as direction and rate of both horizontal and vertical flight. Thus the pilot must be provided with a control unit in communication with the flight computer of an attached flight platform. At the same time, as a temporary and not often used option, the flight platform of the present invention should be simple to use with existing aircraft, that is, few if any changes should be made to the aircraft. It is therefore preferred that a control unit used by a pilot to control a flight platform of the present invention be in wireless communication with the flight computer of the flight platform.

Although the turbofans of a flight platform of the present invention are powered by the thrust produced by the engines of an attached aircraft, other components of the flight platform require power, especially electrical power. These include the flight computer, the platform release mechanisms and turbofan thrust directing mechanisms.

There are many methods to supply the power necessary for operation of the peripheral systems of a flight platform of the present invention. Such methods include the use of fuel cells, power packs, capacitors, generators and batteries as depicted hereinabove. Since it is expected that most often a flight platform is operational for only short times during a single flight the capacity and physical size of a power supply

can be modest. However, for maximum flexibility it is most preferred to integrate an electrical generator to produce electricity when needed. Clearly the addition. of an electrical generator to one or more of the turbofans of a flight platform of the present invention is well within the skill of one skilled in the art. Combining two sources of power, for example batteries to power the communication systems and flight control computer while powering the flight control surfaces with the help of the generator is a most preferred embodiment, as depicted in hereinabove.

One skilled in the art recognizes that the thrust directing ducts, such as 36, of a flight platform of the present invention are subjected to high thermal and physical stress. Many engineering solutions exist to ensure that the thrust directing ducts remain undamaged by use. One solution is to cover the surface of the ducts partially or completely with ceramic heat-resistant tiles such as used in the space shuttle built by the National Aeronautics and Space Administration of the United States.

Flight platform 10 of Figure 1 is depicted as having thrust directing ducts 36 that are openable and closeable using openable vents 41 in order to allow flight control. As is clear to one skilled in the art, allowing thrust directing ducts to be openable and closeable is an optional design feature. It is entirely possible to design a platform of the present invention having fixed thrust directing ducts.

The flight platform of the present invention is most advantageously constructed from lightweight composite materials. However the great expense of composite materials coupled with the disposable nature of the flight platform of the present invention means that standard materials such as aluminum and steel are preferred.

Optional features that can be added to a flight platform of the present invention allow recovery and reuse of a flight platform. Such features include soft-landing devices such as parachutes or airbags, flotation devices for sea recovery, and radio or light beacons to allow recovery crew to find used and subsequently discarded flight platforms.

It is important to note that in some uses there is no need to discard a VTO platform of the present invention. If it is necessary to simply transport aircraft from one location to another, the platform can remain attached to the aircraft. The aircraft lands vertically with the platform upon arriving at the desired location.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.