Aeronautics and astronautics – Aircraft – heavier-than-air – Airplane and fluid sustained
Reexamination Certificate
2001-07-16
2003-02-18
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Aircraft, heavier-than-air
Airplane and fluid sustained
C244S02300R, C244S199100, C180S116000, C180S120000
Reexamination Certificate
active
06520449
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates initially, and thus generally, to lifting platforms and techniques for improving the performance thereof. An example of a lifting platform is disclosed in applicant's co-pending application Ser. No. 09/728,602 entitled “Lifting Platform,” the subject matter of which is herein incorporated by reference. Furthermore, the present invention relates to vortex flow and reference should be made to applicant's application Ser. No. 09/316, 318 entitled “Vortex Attractor,” the specification of which is herein incorporated by reference. Particularly, the present invention discloses a new lifting platform arrangement which uses a toroidal vortex flow to provide positive rotational stability and overcome prior art limitations in the field of lifting platform stability.
BACKGROUND OF THE INVENTION
It is contemplated that the present invention could relate to many possible fields. Initially, it is thought that the invention could apply to fields including, but in no way limited to, hovercraft and other ground effect vehicles. Furthermore, the present invention may apply to fields such as vertical take-off and landing (VTOL) vehicles and turbine engines.
Additionally, the present invention relies upon background information pertaining to the inventor's teachings in the field of vortex attractors and generally, to vortex flow.
Ground Effect Vehicles
In the most conventional sense, the means for any type of levitation has been dominated by a single lift mechanism: the wing. The wing yielded a mode of travel that was a substantial improvement in many ways over other ground-based modes of travel. However, in some applications, wings have some important shortcomings.
Some important shortcomings will be enumerated below:
a) The velocity asymmetries around the surfaces of wings are the basis for the lift they generate. When wings move through the air, they produce substantial drops in pressure at their upper and lower surfaces. The forces generated on the upper and the lower surfaces of the wing, however, point in opposite directions so that they almost completely cancel out.
b) Because wings have low lift factors they have to be large in order to generate a practical amount of lift. The large size of the wings causes them to create a lot of drag when they move through the air.
c) Winged aircraft have a fairly narrow range of speed that they work well in. In order to get off the ground they must have a much larger wing than they need after they have gained speed. The large wing needed to take off creates a lot of drag at high velocity. That makes if very hard to fly at supersonic or hypersonic speeds. Importantly, in regard to the present invention, it makes them very difficult to generate lift at low speeds.
d) Wings have to be moved at fairly high velocity in order to produce practical amounts of lift. That means that they have a lot of room to operate and that winged aircraft are dangerous to bystanders. That is true even for rotary winged craft (helicopters).
e) Wings waste a lot of energy because they shed powerful vortices into the passing air as they generate lift. The energy that goes into those vortices contributes nothing to the generation of lift by the wing.
f) Wings can suddenly stop producing lift. If a winged aircraft flies too slowly the wings stall and can cause a crash.
g) Wings can't produce lift when they are standing still. To make a craft that can hover while it is standing still, means that the wings must be incorporated into a mechanism that swings them through the air. That mechanism and the wing together is called a rotary wing mechanism. It is very complicated and requires a lot of maintenance to operate reliably.
h) Rotary wing mechanism is inefficient.
i) Rotary wing craft are complicated and thus require a lot of maintenance.
j) The rotary wing mechanisms operate asymmetrically when a helicopter moves forward through the air. Without a corrective mechanism the helicopter produces greater lift on one side than the other side. The forward sweeping wings would experience a much higher air velocity than an aft sweeping wing. An elaborate hinge system is able to correct some of those air flow asymmetries at low speed. However, there is no corrective mechanism that allows a helicopter to operate at speeds faster than 250 m.p.h.
Thus, to address certain of these concerns, e.g., the ability to efficiently and cost-effectively hover and traverse at speeds safe to surrounding persons, various types or designs of ground effect or air cushion devices have been developed over the years. Ground effect crafts, or “hovercraft”, are any of the machines characterized by movement in which a significant portion of the weight is supported by forces arising from air pressures developed around the craft, as a result of which they hover in close proximity to the Earth's surface. It is this proximity to the surface that chiefly distinguishes such craft from aircraft, which derive their lift from aerodynamic forces created by movement through the air.
Two main classes of air-cushion vehicles exist: those that generate their own pressure differential irrespective of forward speed; and those, more closely related to true aircraft, that require forward speed before the pressure differential can be generated. The former are classed as aerostatic craft (ACVs); the latter are called aerodynamic ground-effect machines (GEMs). Perhaps the first man to research the air-cushion vehicle concept was Sir John Thornycroft, a British engineer who, in the 1870s, began to build test models to check his theory that drag on a ship's hull could be reduced if the vessel were given a concave bottom in which air could be contained between hull and water. His patent of 1877 emphasized that “provided the air cushion could be carried along under the vehicle” the only power that the cushion would require would be that necessary to replace lost air. Neither Thornycroft nor other inventors in following decades succeeded in solving the cushion-containment problem. In the meantime, aviation developed and pilots early discovered that when they were flying very close to land or water surface their aircraft developed greater lift than in free air. Through research, it was soon determined that the greater lift was available because wing and ground together created a “funnel” effect, increasing the air pressure. The amount of additional pressure was found to be dependent on the design of the wing and its height above ground. The effect was strongest when the height was between one-half and one-third of the average wing chord.
Practical use was made of the ground effect in 1929 by the German Dornier Do X flying boat, which achieved a considerable gain in performance during an Atlantic crossing wherein it flew close to the sea surface. World War II maritime reconnaissance aircraft also made use of the phenomenon to extend their range.
In the 1960s, American aerodynamicists developed an experimental craft, making use of a wing in connection with ground effect. Several other proposals of this type were proffered, and a further variation combined the airfoil characteristics of a ground-effect machine with an air-cushion lift system that allowed the craft to develop its own hovering power while stationary, then build up forward speed, gradually transferring the lift component to its airfoil. Although none of these craft got beyond the experimental stage, they were important portents of the future because they suggested means of using the hovering advantage of the air-cushion vehicle and overcoming its theoretical speed limitation of around 200 miles per hour (320 kilometers per hour), above which it was difficult to hold the air cushion in place. These vehicles are known as ram-wing craft.
In the early 1950s, engineers in the United Kingdom, the United States, and Switzerland were seeking solutions to Sir John Thornycroft's 80-year-old problem. Christopher Cockerell of the United Kingdom is now acknowledged to have been the father of the H
Barefoot Galen L.
Vortex Holding Company
Ward & Olivo
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