Sail propulsion element, sail propulsion vehicle

Abstract

The present invention relates to a sail propulsion element comprising: a mast (3); an inflatable sail (1) consisting of two substantially fluid-tight adjacent surfaces (4a, 4b) joined together along their periphery, between which at least one cavity is formed closed around the mast (3) and including an upper part, a lower part, a leading edge (6) and a trailing edge (7); at least one air conduit arranged between the inside and the outside of the sail cavity; at least one means for injecting air into the cavity, the sail having, when inflated, a profile which remains permanently symmetrical regardless of the movement of the propulsion element or the direction and strength of the wind; a headboard arranged in an upper part of the sail; and a sail receptacle arranged in a lower part of the sail between the leading edge (6) and the trailing edge (7). The sail propulsion element is characterized in that the sail comprises a plurality of cells (5) along the length of the sail, each of the cells (5) extending from a leading edge (6) to a trailing edge (7), the cells (5) being spaced apart by ribs (8) made of a first soft material that is air permeable.

Description

[Technical field]

[0001] The present invention relates to inflatable sails and is in the field of sail propulsion or hybrid sail propulsion. [Background technology]

[0002] Below are notes on some definitions used below: -Reefing: The process of partially furling a sail from the bottom to reduce its surface area in order to adapt it to the strength of the wind. Reefing can be done manually or automatically. -Reefing bands: partially reinforced horizontal zones for attaching reefing turning blocks, e.g. with grommets or pulleys. These reefing bands are placed at the height of the reefing point of each rib of the sail. There are as many reefing bands as there are possibilities to reef the sail. -Lazy Jack: A device for guiding a sail during reefing or dropping operations. -Boom: A horizontal spar connected to the base of the mast that holds and allows the orientation of a particular sail. The boom may also receive the sail when it is dropped. Certain yachts have mast rollers, in which case the sail is stowed in the mast. - Luffing: A luffing sail is one where the sail has not been properly hauled and is partially deflated. A well-trimmed sail should be at its luffing limit. If the sail is properly filled, it will not luff and will be able to catch the wind and sail away. -Leading Edge: The front part of an aerodynamic profile (wing, propeller, etc.) where the fluid splits into two streams. - Trailing Edge: The characteristic part of any profile (wing, keel, rudder blade, etc.) that receives a flow of fluid (air, water, etc.) from both sides. It refers to the part opposite to the directional concept, or in other words the rear part when viewed from the direction of the flow. -Headboard: The top edge of the sail that conforms to the contours of the top of the sail. -Dropping: Lowering the sail. -Hoisting: Raising the sail. - Rigging: The set of fixed and moving parts of a sailboard-type boat that allows the boat to be propelled and steered. - Sail Receptacle: In addition to receiving the dropped sail, it can incorporate other functions to accommodate tension provided by the sail or to house other actuators, energy storage sensors, control modules, etc. used in the operation of the sail. -Hydrodynamic drag: the friction between the boat and the water. The more drag there is, the slower the boat will be. - Aerodynamic drag: The component of the force acting in the opposite direction to the direction of movement of an object moving through a fluid. According to the present invention, the sail generates aerodynamic drag. - Aerodynamic lift: The component of the force acting perpendicular to the direction of movement of an object that is subjected to the force acting on the object as it moves through a fluid. According to the present invention, the sail generates aerodynamic lift. -Relative or apparent wind: The vector sum of the wind caused by the boat's own speed and the actual wind speed. -Resultant aerodynamic force: The vector sum of aerodynamic lift and aerodynamic drag.

[0003] A sail propulsion element comprising an inflatable sail with a symmetrical profile is known from WO 2017 / 221117. The propulsion element comprises an inflatable sail consisting essentially of two substantially fluid-tight adjacent faces joined together along their periphery to form at least one closed cavity. The element further comprises a conduit arranged between the inside and the outside of the cavity and a means for injecting air into the cavity. When inflated, the sail has a profile that remains permanently symmetrical, regardless of the movement of the element or the direction or strength of the wind. The sail of this document is constantly inflated while it is being used for sailing.

[0004] Unfortunately, such soft sails have the drawback of not being able to provide suitable inflation levels for the various stages of their use, especially the hoisting and dropping stages. Specifically, unlike rigid sails, soft sails do not have clearly defined positions for these stages of operation (hoisting and dropping). During these stages, it is important to keep the sail close to the axis of symmetry of the sail profile to prevent the sail from falling into the water or getting caught on nearby elements, or from collapsing into a peak shape suitable for compact storage. Furthermore, it is important to maintain a slight pressure within the sail during the dropping or reefing stages of the sail to prevent the sail from becoming luffing, which may shorten the life of the sail.

[0005] Finally, such sails require numerous air inlets so that they can be hoisted when furled, and as a result, need to be adapted to the fabric structure from which they are made without allowing for rapid and reliable deployment of the furled sail.

[0006] Similarly, WO 2009 / 043823 discloses a paraglider in which the profile of the wing, extending from the leading edge to the trailing edge, comprises a number of cells in the length direction of the sail, spaced apart from one another by ribs, the paraglider being provided with various air intakes downstream, which serve to fill the first storage space during flight.

[0007] Unfortunately, such sails are made up of different types of cells, with or without openings intended for the passage of air, which are provided not only to distribute the air evenly and continuously from cell to cell until the folded sail is fully deployed, but also to allow the air to escape during partial or total descent of the sail, without the risk of it falling into the water. Finally, the irregular distribution of the openings over the volume of the sail tends to give rise to difficulties in deploying the sail, since the openings are not properly positioned to allow the passage of air, and as a result there is a high possibility of blockages occurring at the openings. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2017 / 221117 [Patent Document 2] International Publication No. 2009 / 043823 Summary of the Invention

[0009] There is therefore still a need for an inflatable sail that when dropped / inflated transmits air evenly and uniformly throughout the entire volume of the sail, without luffing and without risk of damage, while remaining correctly on its axis of symmetry along the mast, and that can be repeatedly deployed, fully or partially, manually or automatically. Furthermore, even in the deployed position, there is a need to be able to place the inflation device in the sail receptacle, in order to minimize consumption of the inflation device and simplify power supply.

[0010] One subject of the invention is a sail propulsion element comprising: a mast; an inflatable sail consisting of substantially two fluid-tight adjacent surfaces joined to each other along their periphery, between which is formed at least one cavity closed around the mast, and including an upper part, a lower part, a leading edge and a trailing edge; at least one air conduit arranged between the inside and the outside of the sail cavity; at least one means for injecting air into the cavity, the sail having, when inflated, a profile that remains permanently symmetrical regardless of the movement of the propulsion element or the direction and strength of the wind; a headboard arranged in the upper part of the sail; and a sail receptacle arranged in the lower part of the sail between the leading edge and the trailing edge.

[0011] The propulsion element according to the invention is characterized in that the sail comprises a plurality of cells in the length direction of the sail, each cell extending from the leading edge to the trailing edge, the cells being separated by ribs made of a first soft material permeable to air, for example a 3D type structure.

[0012] Thus, a rib delineates two adjacent cells, and a number of ribs are provided to delineate the various cells of the sail. It is advantageous for the ribs to allow air to pass, in order to minimize pressure losses, but also to transmit loads. The importance of being able to minimize the pressure loss experienced by the air when the sail is inflated, i.e. the level of pressure that must be relieved in order for the air to travel its entire path, should be emphasized here. In particular, when the sail is dropped and the operator wishes to inflate it with air, it is important in the solution of the invention that the blown air arriving from the bottom of the sail does not remain trapped in the lowest box section (or bottom cell) but can reach as easily as possible the top of the sail (top cell of the sail) during inflation. Placing a rib between each cell that allows air to pass, as proposed by the invention, can provide a solution to this problem, since the entire surface area of ​​the rib can now be used to allow air to pass. Thus, in contrast to prior art configurations where the air has to pass through several holes formed in the ribs and where the way the ribs are stacked can result in high pressure losses when dropping the sail, here the air always manages to find an easy path to fill all the cells, especially the cells at the top of the sail.

[0013] The propulsion element according to the invention has various advantages:

[0014] Thanks to the continuous passage of air through each rib, the air circulates evenly and uniformly from one cell to another. In particular, despite the presence of only a single air injection point, the ribs allow the air to pass over substantially its entire surface area, making it possible to obtain a substantially uniform internal pressure throughout the volume, thereby ensuring the precision of the sail's profile. The presence of such ribs facilitates automatic inflation and furling after the sail has been deflated, in particular using only the fan present in the sail receptacle and therefore at the bottom of the sail, without any need for external intervention. The air-permeable ribs improve the transmission of air compared to existing solutions, while locating the fan at the bottom of the sail. Thus, in prior art inflatable sails, the air arrives through multiple orifices and fans located at the leading edge of the sail, so that the power supply cable has to pass through the various cells to connect the fan. The use of air permeable ribs over substantially the entire surface area simplifies power supply to the actuator (fan) so that the actuator can be located in a sail-housed receptacle, i.e., underneath the sail, while allowing uniform inflation throughout the entire volume of the sail. The fan can be replaced by other means of injecting air, such as a blower or pressurized air supply.

[0015] A symmetrical profile is one that is perfectly symmetrical when the pressures on the inner and outer arcs of the wing are equal, but can vary slightly to account for the flexibility of the sail (which is called a wing when referring to an inflated sail) when the profile deforms slightly due to a pressure difference between the inner and outer arcs of the sail.

[0016] Preferably, each rib comprises a reinforced zone delimited around the mast and made of a composite soft material, the rib being reinforced to allow it to transfer loads.

[0017] Preferably, the first flexible material and the second flexible material are woven materials having different weaves.

[0018] Preferably, the first soft material has a mesh size of about 2 to 4 mm.

[0019] Preferably, the second, soft material has a mesh size of about 2 to 4 mm.

[0020] Preferably, the rib includes a central band extending from the leading edge to the trailing edge.

[0021] Preferably, the central band is made from a second, soft material. In an alternative form of the invention, the central band is solid.

[0022] Preferably, the central band has a width in the range of 1 to 10 cm.

[0023] Preferably, the cells are spaced apart by a distance between 0.8 and 2 m.

[0024] Preferably, the individual reinforcing members are evenly spaced along the leading edge.

[0025] Preferably, for the operation of hoisting or dropping the sail, a guideline is arranged in the closed cavity of the sail, which extends from the leading edge to the trailing edge of the sail, passing through the headboard and the sail receptacle, the guideline passing through the individual stiffening members. It is recalled that the guideline is a device created with line rope rigging in order to ensure that the sail is geometrically correctly positioned during the hoisting or dropping phase of the operation. In particular, the rib of the sail, which may be considered for example in the middle of the height of this sail, is positionally constrained by the fact that the mast passes through a hole made for that purpose, but apart from the stiffness of the sail (which is low), there is nothing to prevent it from rotating relative to the mast under the effect of the pressure applied to it. Such a rotation would cause the sail to twist and, as a result, have the effect of modifying the profile of the sail in a way that adversely affects its performance. To avoid this twisting, each rib has a guideline passing through it at a position sufficiently distant from the mast. When hoisting or dropping, the rib slides along the mast and along this guideline.

[0026] Preferably, if a guide line is present, it is formed as one piece and is fixedly attached to the sail receptacle at its trailing edge and movable by rollers at its leading edge, or movable by rollers in the sail receptacle at its trailing edge and fixedly attached to the leading edge, the guide line being positioned along the headboard so that it can move on at least one pulley between the trailing edge and the leading edge.

[0027] Preferably, if a guide line is present, it is formed in two parts, the first part on the trailing edge side being fixed or otherwise movable on a pulley on the headboard and movable by rollers in the sail receptacle; the second part on the leading edge side being fixed or otherwise movable on a pulley on the headboard and movable by rollers in the sail receptacle.

[0028] Another subject of the invention is a vehicle with sail or hybrid propulsion comprising at least one sail propulsion element as described hereinabove, a hull and a mast fixed to the hull but still retaining a rotational degree of freedom, the vehicle being characterized in that a large part of the mast is located inside the cavity of the inflatable sail as described above.

[0029] Preferably, the mast is located inside the cavity of the inflatable sail.

[0030] Preferably, the sail is oriented according to the wind direction and according to the direction of travel of the vehicle, either manually or automatically.

[0031] By hybrid propulsion vehicle according to the present invention is meant sail propulsion combined with another propulsion source, such as propulsion by a propeller driven by an electric motor or an internal combustion engine, and having as energy storage sources batteries, hydrogen (with fuel cells), natural gas or fuel oil.

[0032] By vehicle is meant any vessel capable of moving on land or water, whether on wheels or not.

[0033] The invention is illustrated with the aid of the following figures, which are schematic and are not necessarily drawn to scale. [Brief description of the drawings]

[0034] [Figure 1] 1 shows the projection of various physical forces, and in particular the resulting aerodynamic forces, which are applied to a watercraft, for example of the motor sailboard type. [Diagram 2] FIG. 2 is a schematic front view of a fully hoisted sail propulsion element according to the present invention; [Diagram 3] FIG. 2 is a schematic front view of a sail propulsion element including, in part, ribs; [Figure 4] FIG. 2 is an enlarged schematic diagram of a portion of a sail propulsion element according to the present invention, including a rib. [Diagram 5]FIG. 2 is a schematic front view of a rib of a fully furled sail propulsion element according to the present invention; [Figure 6] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Before describing the sail propulsion element that is the subject of the present invention in more detail with the aid of the figures mentioned above, a note on some hydrodynamic and aerodynamic definitions is given below.

[0036] A sail-propelled vehicle, called a sailboat or vessel, is in contact with air and water. From a physical point of view, the hydrodynamic and aerodynamic forces acting on the hull, sail and appendages (centerboard, keel, rudder, propeller) are the main factors.

[0037] As shown in Figure 1, aerodynamic forces (or sail thrust) are the result of air being deflected by at least one sail. Aerodynamic forces are related to the position and surface area of ​​the sail, and the position and strength of the relative wind. Drag is in the direction of the relative wind, and lift is in a direction perpendicular to the relative wind, which is not always perpendicular to the sail. For example, at 0°, a symmetric profile produces no lift, since the air travels exactly the same distance across the outer and inner arcs. At this point, only drag is produced.

[0038] Also, the aerodynamic forces generated by a sail can be resolved, in the frame of reference of the boat rather than the sail, into a sail propulsion force (along the axis of the boat's travel) and a drift force (perpendicular to the axis of the boat) that can cause the boat to heel (heel is the lateral tilt of the board as caused by an external phenomenon such as wind).

[0039] Hydrodynamic forces are the result of the friction of water against the hull and centerboard or keel and various underwater appendages. Their direction depends on the opposing aerodynamic forces, the propulsive forces in hybrid mode, sea conditions and currents. The longitudinal component is called hydrodynamic drag and the transverse component is called side force, anti-heeling force or hydrodynamic lift. The direction and strength of hydrodynamic forces do not depend only on aerodynamic forces. For a surface vessel (boat) operating in hybrid mode (wind and another energy source), the hydrodynamic forces will be highly dependent on the vessel speed generated by the engine or motor propulsion, e.g. sea conditions and currents.

[0040] If the sail force is greater than the hydrodynamic force, the boat will accelerate. If the sail force is less than the hydrodynamic force, the boat will slow down. Additionally, if the aerodynamic force is greater but points towards the rear of the boat, the boat will slow down. If the hydrodynamic force is in the direction the boat is moving (because the current is strong), the boat (a sailboat) will accelerate.

[0041] By optimizing the trim of the sail, the sailboat will achieve its maximum performance in terms of sail thrust in the direction of travel. In particular, by optimizing the sail angle with respect to the relative wind and the direction of travel of the boat, and by trimming the sail surface area, the sail thrust can be maximized along the axis of the boat. Depending on the wind conditions, additional trimming movements may be required to vary the internal pressure of the sail. This allows to increase the speed of the boat through sail thrust, or on the other hand to maintain the same speed while simultaneously reducing the consumption of other energy sources.

[0042] FIG. 1 again illustrates each of the above defined parameters with a unique specific reference number, all as listed below. a: Lift b: drag c: aerodynamic resultant force d: Aerodynamic thrust (along the axis of the ship) e: Aerodynamic drift force f: relative wind g: Relative angle between wing and boat axis (e.g. 15°) h: angle between relative wind and boat axis (e.g. 30°) i: Propeller thrust j:Haru k: Sail l: Mast m: center of aerodynamic thrust n: Propeller o: fixed part of the sensor (hull reference frame) p: Sensor of the moving part (sail reference frame) The information given in FIG. 1 allows the transition from sensors in the hull reference frame of data to sensors in the sail reference frame of data and vice versa.

[0043] Figure 2 shows a propulsion element with the general reference number 1 according to the invention, which is attached to the hull 2 ​​of a boat of sailboat type using a free-standing mast 3. The mast 3 is connected to the hull using supports (not shown) for absorbing the loads of physical forces. The loads are measured on the supports or on the mast itself. The sail is composed of two adjacent surfaces 4a, 4b connected to each other to form a closed cavity. Each surface 4a, 4b can be made of a material with several layers to achieve different properties such as mechanical strength, airtightness, fire resistance, UV resistance, etc.

[0044] The sail 1 comprises a number of cells 5 distributed longitudinally across the full height of the sail 1. Each cell 5 extends from a leading edge 6 to a trailing edge 7 (as shown in Figure 5). The cells 5 are spaced apart by approximately 1m.

[0045] As shown in figure 3, the cells 5 are separated from each other by ribs 8. Each rib 8 is made of a first material, for example a woven material composed of warp threads filled with a weft thread of about 3 mm, the threads potentially being coated with a compound such as PVC. This type of 3D weave ensures the correct passage of air even when the sail is furled in drop mode.

[0046] This first material, which can be a woven fabric, is attached to the sail by adhesive means, sewing, fusing, or other means that allow a secure attachment, without any subsequent coating, as this would block the pores of the material and prevent air from circulating properly.

[0047] It is also possible to use as the first textile material a textile which provides a gradual transition between the material constituting the outer layer of the sail 1 and the first textile material of the ribs 8. It is also possible to use a filament membrane.

[0048] As shown in Figure 4, each cell 5 is separated by a rib 8. During hoisting / dropping, air, e.g., in the sail receptacle, is drawn or sucked into the sail cavity, as handled by a fan or some other expansion means. Air passes through the ribs 8 (arrows 9) from top to bottom or bottom to top (depending on whether the sail is expanding or contracting), allowing for a substantially uniform distribution of internal pressure within the sail 1, whether the sail is fully deployed, reefed to reduce sail area, or beginning to expand with the ribs stacked.

[0049] The configuration of the ribs 6 also makes it possible for them to not only react to the loads associated with the internal pressure of the sail 1, but also to transmit the aerodynamic pressures exerted on the profile of the sail 1 to the mast 3. In effect, the ribs react to the internal pressure of the sail and are also able to transmit aerodynamic forces.

[0050] As symbolized (arrow 10), the internal pressure of the sail acts on the walls of the sail.

[0051] The particular choice of the first textile material according to the invention for the ribs 8, and in particular the orientation of the yarns of which this material is made, allows a correct transmission of the aerodynamic forces from the sail to the mast 3. There is no disadvantage in a restricted passage of air around the mast 3. What is most important is to allow the air to pass in front (towards the leading edge) and behind (towards the trailing edge) of the ribs. In other words, the ribs are not fixed to the mast but "float". This nevertheless allows the aerodynamic forces to be transmitted and at the same time the air to be uniformly distributed throughout the volume of the sail.

[0052] A first advantage of using a first material through which air passes and which reacts to loads according to the invention, as opposed to individual orifices distributed over the surface of the sail, is that it avoids partial or complete blockage of one or more orifices, which would have a much more detrimental effect on the correct circulation of air within the cavity of the sail 1.

[0053] A second advantage is that it becomes possible to significantly reduce the pressure drop while at the same time maintaining sufficient strength to transmit the load, thereby reducing the power and therefore the energy consumption of the inflation device.

[0054] A final advantage of this first material is that the leading edge fan can be omitted: in the solution of the invention, the fan located in the sail receptacle will satisfy most of the tasks of sucking or extracting air.

[0055] As shown in FIG. 5, the cells 5 allow air to pass upwards over the fully hoisted elements according to the present invention (arrows 9) for hoisting the sail 1.

[0056] The schematic diagram in Figure 6 shows a reinforcement zone 11 at the bottom of the sail, bounded around the mast 3. This zone extends for approximately 7.5 m. 2It is made of a second material different from the first material, for example made with the same material but at a different angle, for example the first material has a weave angle of 0° and 90° and the second material has an angle of ±45° to the first material. In another embodiment, this reinforcement can be achieved by using the same weave as the rib weave and overlapping the two layers of weave at a 45° angle to each other.

[0057] This second material is defined by mesh openings approximately 3 mm in size.

[0058] Figure 5 further shows the presence of a band 12 made of reinforcing material, the width of this band 12 being approximately 80 mm.

[0059] Its function is to distribute forces and limit abrasive wear at the points where various line rigging, such as reefing lines or guide lines, pass through.

[0060] Discrete reinforcing members (not shown) may be evenly spaced along the leading and / or trailing edges of the ribs 6 . EXAMPLES

[0061] The following examples are illustrative only and are non-limiting. The table below lists various possible situations. TIFF2024522119000002.tif59157

[0062] The outer layer of the sail, also called the body, is made of a woven fabric, including the outer and inner layers that are in contact with the outside air. The fabric is a polyester fabric coated with polyurethane. The basis weight of the fabric is approximately 100 m 2 180g / m for sail area 2 It is.

[0063] The top of the sail can be secured with hook and loop fasteners of the Velcro type. The joints between the outer part of the sail and the ribs (internal joints) and the joints between the components of the outer part can be achieved by fusion or adhesive joints or other joining means (e.g. zipper fasteners), which can ensure load transfer while ensuring a sufficiently low level of permeability to be compatible with, for example, existing inflation systems. [Explanation of symbols]

[0064] 1 Inflatable sail 2. Haru 3 Mast 4a surface 4b surface 5 Cell

Claims

1. 1. A sail propulsion element, comprising: a. A mast (3); b. an inflatable sail (1) substantially composed of two fluid-tight adjacent surfaces (4a, 4b) joined together along their periphery to form at least one cavity therebetween closed around the mast (3), the sail including an upper portion, a lower portion, a leading edge (6), and a trailing edge (7); c. at least one air duct disposed between the inside and outside of the cavity of the sail; d. at least one means for injecting air into said cavity, such that when said sail is inflated, it has a profile that remains permanently symmetrical regardless of the movement of said propulsion elements or the direction or strength of the wind; e. a headboard disposed on the upper portion of the sail; f. a sail receptacle disposed between the leading edge (6) and the trailing edge (7) of the lower portion of the sail; Equipped with 1. A sail propulsion element, comprising: a sail comprising a plurality of cells (5) along the length of the sail, each of the cells (5) extending from the leading edge (6) to the trailing edge (7), the cells (5) being spaced apart by ribs (8) made of a first soft material permeable to air.

2. Element according to claim 1, wherein each of said ribs (8) comprises a reinforcement zone (11) delimited around the mast (3) and made of a second soft material of the composite material.

3. 3. The element of claim 2, wherein the first flexible material and the second flexible material are woven materials having different weaves.

4. The element of claim 1 , wherein the first soft material has a mesh size of about 2 to 4 mm.

5. The element of claim 2 , wherein the second soft material has a mesh size of about 2 to 4 mm.

6. The element of claim 1 , wherein the rib comprises a central band extending from the leading edge to the trailing edge.

7. The element of claim 6 , wherein the central band is made from the second flexible material.

8. 7. The element of claim 6, wherein the central band has a width in the range of 1 to 10 cm.

9. 10. The element of claim 1, wherein the cells are spaced apart by a distance of 0.8 m to 2 m.

10. The element of claim 1 , wherein individual reinforcing members are evenly spaced along said leading edge.

11. 11. The element of claim 10, wherein a guide line is disposed within the closed cavity of the sail for hoisting or dropping operations of the sail, the guide line extending from the leading edge to the trailing edge of the sail and passing through the headboard and sail receptacle, the guide line passing through the individual stiffening members.

12. 12. A mobile body with sail or hybrid propulsion comprising at least one element according to any one of claims 1 to 11, a hull and a mast fixed to the hull but still retaining a rotational degree of freedom, the majority of the mast being arranged within the cavity of the inflatable sail.

13. The vehicle of claim 12, wherein the sail is oriented according to wind direction and according to the moving direction of the vehicle, either manually or automatically.

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