WO1993019978A1

WO1993019978A1 - Foil device

Info

Publication number: WO1993019978A1
Application number: PCT/NO1993/000052
Authority: WO
Inventors: Tore Lyngholm
Original assignee: Tore Lyngholm
Priority date: 1992-03-31
Filing date: 1993-03-31
Publication date: 1993-10-14
Also published as: NO921248D0; AU3909293A; NO921248L

Abstract

A paddle or wing for utilizing the forces in flowing media such as gas, air or water, for use in turbines, propulsion of vessels and the like. The paddle or wing is pivotably or pendulously suspended and capable of self-adjustment into an aerodynamic form when a force is directed against one of the lateral surfaces of the paddle or wing. This force will normally result from the fact that the paddle or wing is arranged to be movable transversely to the direction of flow in the medium.

Description

FOIL DEVICE

The present invention relates to an airfoil (hereafter referred to as a "foil") or wing that utilizes the forces in flowing media such as fluids or gases (e.g., water or air). The device may be used in turbines to generate electricity, as a stabilizer system for ships and vessels, as a rudder and keel for steering boats and as a component in a boat sail.

There has always been a desire to exploit the energy in flowing media such as air and water. DE 3018211 describes a wind wheel having wing profiles that may be driven by wind power, where two profiles are steered by a common control arm. UK 2085387 describes an adjustable sail foil having two separate sheets for use on sailboats. US 4179886 shows an apparatus and method for utilizing the energy in waves. DE 2152637, US 4437426 and DE 2740939 all show different shapes for paddles or foils. None of these foils, however, is capable of adjusting automatically to the direction of the moving medium in which the foil is placed, and this is one of the primary objectives of the present invention. The foil in the present invention is capable of adjusting itself so that it automatically directs the lift and the proper angle of attack toward the flowing medium in order to achieve optimal utilization of the kinetic energy in the flowing fluids and gases.

The foil according to the invention may either be freely rotatable about a shaft, or be secured to one or two shafts. In one embodiment form a nose section may be actuated and adjusted by the forces in the flowing medium acting on the foil. The foil is also self-adjusting with respect to the influencing forces, and when such foils are mounted in combination, one can obtain a system which is capable, e.g., of generating electricity from the sea. The foil or wing according to the present invention is characterized in that the foil or wing consists of a body having a droplet-shaped cross section with a movable and forward-directed nose section, and the movable nose section is suspended in the main body by means of a link arm pivotably mounted at a pivot point on the main body and at a link point on the nose section, which enables movement of the nose section along a curved forward section on the main body, such that the nose section is movable between two

10 outer positions for creation of a lifting effect on one or the other side of the foil.

Other embodiment forms of the invention are further charac¬ terized by the remaining claims.

15

In the following, with the aid of examples and figures, some of the embodiment forms of the present invention are shown.

Figure 1 shows an embodiment form of the foil for use in a

20 turbine,

Figure 2 shows the foil placed in a turbine,

Figure 3 shows an embodiment form of the foil as a rudder,

25

Figure 4 shows an embodiment form of the foil as a keel for, e.g., a sailing vessel,

Figure 5 shows an embodiment form of the foil used as a wing

30 profile in a sail, and

Figure 6 shows an embodiment form of the foil as a stabilizer for a ship.

>^•> TURBINE

With reference to Figure 1, an embodiment form of the

Invention consists of a droplet-shaped body 1 with a movable and forward-directed nose section 2. The movable nose section 2 is suspended in the main body by means of link arm 3, pivotably mounted at a pivot point 4. In this manner nose section 2 may be rotated along the curved forward section 6 of main body 1.

The nose section is thus movable between two outer positions to create a lifting effect on one or the other side of the foil. Further, the link point 5 is attached to an additional arm 7 which passes through a joint 8 into link arm 9. Link arm 9 is disposed in a guide means 10, and a pressure spring 12 is arranged between a fillet 11 and guide means 10. On the main body 1 of the foil are provided stoppers 13 to prevent the nose section from locking in its outer position. When a power P is exerted in the direction of the arrow indicated in Figure 1, the foil will undergo a lift as indicated by the direction of arrow PI.

By utilizing the present invention as a turbine, it is possible to generate electricity in bodies of water having a low flow rate.

There are currently three types of flow engines that dominate the market. These are the Francis turbine, the Pelton turbine and the Kaplan turbine.

Of these, the Kaplan turbine accommodates the lowest fall heights, down to about 3 meters.

The turbine provided with foils in accordance with the present invention consists of a plurality of foils/wings mounted peripherally between two wheels connected to a center axle for support and energy outlet (see Figs. 1 and 2). The foils/wings are characterized by the capability of selecting among, for example, positive, neutral and negative lift with respect to the kinetic forces acting upon them. They also have the characteristic of self-correction of the angle of attack toward the flowing medium with respect to the various hydrodynamic conditions to which these are subjected.

The foils/wings may be rotated 360° about their own axis.

Together these form a turbine system cabable of fully utilizing the kinetic energy of the water in a hydrodynami- cally correct manner even if the water flow rate is relative¬ ly low.

RUDDER FOR SHIPS AND VESSELS

Another embodiment form of the invention shows a rudder constructed as illustrated in Figure 3, where a symmetrical profile is hinged 14 together through the thickest area of the profile, and where two shafts 15 pass through at the profile ends and are attached at the ends to two end pieces. The end pieces and shafts together form a quadratic or rectangular frame in which the main piece, or stock, of the rudder is secured at one or both ends thereof.

The profile according to the invention is thus rotatable from side to side about the two end shafts upon being pressed over, as the hinge between the shafts also rotates.

Since the distance between the end shafts 15 is fixed, one or both of the shafts must move by sliding in an axial slot in order to accommodate the depth change occurring in the profile when it is pressed from neutral symmetrical position over into active, asymmetrical position. This movement is also obtainable by means of eccentric suspension. (This is not shown on the drawings. )

Upon rotation of the rudder stock the flow is increased on the pressure side of the rudder, the pressure thereagainst rises, the negative pressure on the negative pressure side of the rudder increases, and these two forces contribute toward pushing/pressing the symmetrical profile over into asymmetri¬ cal position.

The configuration of the two parts of the profile determines the profile's asymmetrical form in active position.

The eccentric suspension or axial displacement determines the amount of deflection or throw the individual profile parts may have relative to each other. By moving the two through- going shafts closer to the hinge connecting the two profile parts, the function of the rudder may be reversed if the center distance of the shafts is less than 50$ of the total depth of the foil.

KEEL SYSTEM FOR SAILING VESSELS

This embodiment form of the foil in the invention functions as an unassisted or independent symmetrical/asymmetrical keel system to prevent a sailing craft from heeling due to wind pressure in the rigging, at the same time as the vessel's drift is limited relative to the direction of travel. (See Fig. 4).

One-hulled sailing vessels have always heeled when sailing with the wind, for example, transversely to the direction of travel.

When a vessel heels, the water line — which is symmetrical with stable vessels -- will become asymmetrical.

This causes a substantial increase in the water resistance for the vessel.

When a sailing vessel heels due to wind pressure in the rigging, it will in addition to confronting the aforemen¬ tioned water resistance also lose some of its effective sail area, as the latter is reduced in step with the heeling of the craft.

If a sailing vessel could remain stable as wind pressure increases, the vessel speed would increase relative to the wind pressure, provided that the contruction of the hull so permitted.

Most of our current keel designs work essentially in accordance with the weight principle and, to a lesser degree, with the utilization of the hydrodynamic energy present at the keel of a vessel in motion. The main function of today's keels is to prevent the vessel from drifting transversely to the direction of travel, where the weight of the keel is the stabilizing factor.

The keel system described herein, however, works according to the principle based on use of the keel for lifting from side to side, in the same way that an airplane wing lifts up^' a plane, but with the difference that the lifting here is directed toward both sides simultaneously.

This means that the lower part of the keel establishes a lifting force that works in the same direction as the force pressing on the sail and causes the vessel to heel, while the upper part of the keel sets up a force/ lift working in the opposite direction to counteract the craft's leeway drift. The lower part of the keel thus straightens up the heeling vessel in accordance with the law of force times length, relative to the upper part of the keel, which has a shorter length to work on but which lifts in the opposite direction.

The result of this is that, in proportion to the velocity of the craft, an asymmetrical wing/keel — although it is acted upon by a water stream flowing directly from the front— will give the water a longer distance to travel; this means that the speed of the water on the convex side of the keel must increase, compared to that on the linear or slightly concave side of the keel.

The velocity increase creates a negative pressure which, in turn, draws the keel in the convex direction.

A symmetrical, water current actuated keel profile lifts with an equal force toward both sides; this is a traditional sailboat keel.

A keel which can be given an asymmetrical form as needed will, in the asymmetrical position, apply the total lifting force to the selected side as, for example, on an airplane where all the forces work substantially upward.

This keel with a foil according to the invention can also have the necessary weight to enable it to fulfill the function of a traditional keel also, in addition to the other properties.

A symmetrical/asymmetrical keel, with the aid of either weight, hydrodynamic energy acquired from the transfer of the force from both sides of a keel to one side only, and by virtue of its capability to exert energy in two directions, can provide a sailing vessel with far more energy for stabiliza¬ tion and prevention of leeway drift, as compared with a traditional symmetrical keel.

As the linear/slightly concave side of the keel does not have an angle of attack directed toward the flowing water, neither does steal any force from the propulsion energy of the vessel. It merely transfers the energy, collecting it at all times on the convex side, which in turn straightens up the vessel, gives the sails a greater area, reduces hull resistance and provides the vessel with more available energy for propulsion. BOAT SAIL WITH FOIL PROFILE

Research, development and experimentation is currently being conducted with fixed wing profiles having the purpose of more effectively using the wind as a means of propulsion for vessels.

Today there are found vessels capable of sailing at a relatively high speed directly against the direction of the wind with the aid of wing profiles.

This shows that a wing profile is far more effective than the traditional sail.

The greatest disadvantage of wing profiles on vessels is, however, that compared with a traditional sail, the wing cannot be hoisted up and down when conditions so require, the wing cannot be reefed easily and quickly as conditions require, the billowing or cross-sectional profile of the wing cannot be adjusted according to prevailing wind conditions and the vessel course — which in turn results in poor utilization of the wing's power potential, nor can the wing be mounted on vessels with traditional sail rigging without their first being reconstructed for this particular purpose.

A sail having foils in accordance with the invention has a convex negative pressure side and a relatively linear pressure side, which makes it possible to go higher up against the direction of the wind because the relatively flat pressure side of the sail demands considerably less of the wind's angle of attack in order to maintain the shape of the sail/wing; this is because the "thickness" of the wing profile creates the "extra" path over which the wind must travel around the convex "negative pressure side" of the wing/sail, where the wind velocity increases and negative pressure occurs. This, in turn, pulls the vessel forward, (See Figs. 5 and 6. )

A wing profile having a convex negative pressure side and a relatively linear pressure side requires little or no angle of attack in order to create negative pressure on the convex side of tϊie profile.

A wing profile such as the one described herein is con¬ structed between two layers of sailcloth.

STABILIZER SYSTEM FOR SHIPS AND VESSELS

The system that will be decribed herein may be used for most currently recognized types of vessels.

Here we will show how the stability of a vessel may be radically increased and combined with converted propulsion energy acquired from the rolling movements of the vessel.

When a vessel heels due to wave movements acting on the hull, the vessel's symmetrical water line becomes asymmetri¬ cal, resulting in increased water resistance. A stable vessel therefore has better energy economy per distance sailed, compared with a corresponding unstable vessel under the same conditions.

The stabilizer system used today is based principally on gyrostabilization with the aid of mechanically operated foils — a complicated, vulnerable and expensive solution, internal tank systems that occupy a great deal of space, and the traditional bilge keel that is mounted externally on the vessel bilge along 1/3 of the total length of the craft. The latter is the system most widely used on merchant vessels today. The independent stabilizer system with foils according to the present invention functions in the following manner: A foil/wing is constructed which has the capability of control¬ ling the lift in accordance with the forces acting upon it. (See Fig. 6). To accomplish this, a symmetrical, flexible, correctly shaped foil having the necessary width and depth is mounted at the forward and rear edges thereof by means of shafts passing therethrough.

As the foil is either adequately flexible or mechanically hinged, it will if mounted, e.g., successively in series on a vessel in the same area where the traditional bilge keel is located, it will have the following effect relative to the horizontal and vertical movements of the craft: A craft moving forward without rolling movements is not subjected to vertical water currents along the bilge where the stabilizer system is mounted. Bilge keels are mounted in such a manner that they follow the flow pattern of the water along the vessel. In a stable ship, therefore, the foil is in neutral, droplet-shaped position.

But if the vessel heels while it is in motion, there occurs a vertical/horizontal flow against the foils. The effect of this combination flow contribute toward pressing/lifting the foils from the symmetrical neutral position to asymmetrical active position.

The lift thus exerted on the individual foil is comparable to the same lift that causes an airplane to rise from the ground or "the "lift" enabling a propeller to move a vessel through the water.

The foils on one side of the ship produce upward lift, while the foils on the other side of the ship provide negative lift, which in turn prevents further rolling of the ship in proportion to the total effect of the combined number of foils mounted on the ship. Mounting the foils in close succession will enhance the effect of the invididual foil relative to the venturi effect which thus occurs due to the flexible tail of the foil, which allows a certain amount of water to flow in over the negative pressure side of the foil. The venturi effect is a well known kinetic phenomenon from the sport of sailing, for example.

The foils may be mounted along the side of the ship within a protective frame system that is welded or mounted in the same manner as the traditional bilge keels today are mounted.

Claims

P a t e n t C l a i m s

1.

A foil/wing for utilizing the forces in flowing media, such as gas, air or water, for use in turbines, propulsion of vessels and the like, c h a r a c t e r i z e d i n that the foil or wing consists of a body having a droplet-shaped cross section (1) with a movable and forward-directed nose section (2), that the movable nose section is suspended in the main body (1) by means of a link arm (3) pivotably mounted at a pivot point (4) on the main body (1) and at a link point (5) on the nose section (2), permitting movement of the nose section along a curved forward section (6) on the main body (1), such that the nose section is movable between two outer positions in order to create a lifting effect on one or the other side of the foil.

2.

A foil/wing according to claim 1, c h a r a c t e r i z e d i n that also attached to the link point (5) is an addition¬ al arm (7) which proceeds through a joint (8) into an additional link arm (9), and that the additional arm (9) is carried in a pivotable guide means (10), and a pressure spring (12) is arranged between a fillet (11) and the guide means (10), and that both sides of the main body (1) are provided with stoppers (13).

3.

A foil/wing according to claims 1 - 2, c h a r a c t e r¬ i z e d i n that the foil/wing is attached to a rack, hull or the like by means of pivot points in the pivot points (8).

4.

A foil/wing, c h a r a c t e r i z e d i n that it consists of a central cylindrical or elliptical part and two rotatable parts connected thereto which are movable relative to the center part, wherein the forward part has approximately parabolic cross-section and is adapted to fit to said cylindrical or elliptical part, and the nose section and tail section are pivotably joined in the center part are rotata¬ ble about the center part and with one another by a link arm, said link being divided into two sections, articulated so as to accommodate depth change in the structure, so that the two pivotable parts are movable independently of each other in order thereby to create a lifting effect on one side or the other of the foil in accordance with the placement of the anchoring points; and if the foil/wing is mounted in the center section without a link arm, the function will be reversed in accordance with the forces acting on the foil.

5.

A foil/wing which is constructed from a continuous, flexible material having a rounded-tip nose section that proceeds into main body of conical cross-section and stern sector, c h a r a c t e r i z e d i n that the foil has two spaced apart anchoring points permitting the active surface to be movable between said anchoring points so that the foil creates a lifting effect; by placement of the anchoring points closer together, the lifting effect will be reversed.

6.

A foil/wing, c h a r a c t e r i z e d i n that the foil/ wing between a double sail cloth constitutes a body which in cross-section forms a droplet-shaped body, the profile of which is adjustable in thickness, independently of an external influence, allowing the foil/wing unassisted to assume the correct position in accordance with the forces acting upon it and the work that it will carry out in asymmetrical position, so that the lifting effect is directed in accordance with the prevailing actuating forces.