Sail propulsion element, Sail-powered vehicle

Abstract

The invention relates to a sail propulsion element comprising a mast (3), an inflatable sail (1) consisting essentially of two adjacent surfaces (4a, 4b) which are substantially sealed and connected to each other around their periphery, thereby forming between them at least one closed cavity around the mast (3), said sail comprising an upper part, a lower part, a leading edge (6) and a trailing edge (7), at least one air duct arranged between the inside and the outside of the cavity of the sail, at least one means for injecting air into said cavity, the sail, once inflated, having a profile which remains permanently symmetrical, regardless of the movement of said propulsion element, the direction or intensity of the wind, a head arranged on the upper part of the sail, and a sail receptacle arranged between the leading edge and the trailing edge on the lower part of the sail.The element is characterized in that the sail comprises a plurality of cells (5) in the spanwise direction of the sail, each cell (5) extending from the leading edge (6) to the trailing edge (7), said cells (5) being spaced apart by a rib made of a first flexible material. Figure for abstract: figure 3.

Description

Title of the invention: Sail propulsion element, Sail propulsion vehicle

[0001] The invention relates to an inflatable sail and is situated in the field of sail propulsion or that of hybrid sail propulsion.

[0002] We recall below some definitions used in the following: - Reefing: consists of reducing the surface area of ​​a sail by partially folding it down, in order to adapt the surface area of ​​the sail to the strength of the wind. Reefing can be done manually or automatically. - Reefing bands: horizontal areas with reinforced sections allowing the attachment of reefing lines, for example with eyelets or pulleys. These reefing bands are arranged on the sail at the rib at each height where a reefing is planned. There are as many reefing bands as there are possibilities for reducing the sail area. - Lazy jacks: (in English lazy jack) device for carrying out reefing and lowering maneuvers of the sail. - Boom: horizontal spar, hinged at the base of the mast, which allows certain sails to be held and oriented. The boom can also accommodate the sail when it is lowered. Some sailboats have a mast furler; the sail is then stored in the mast. - Flaseyer: A sail that fluffs is an insufficiently trimmed sail that partially deflates. A well-trimmed sail should be at the limit of fluffing. With a fully inflated sail, there is no fluffing, which allows you to stay facing the wind. - Leading edge: front part of an aerodynamic profile (wing, propeller, etc.) where a fluid will separate in two. - Trailing edge: characteristic part of any profile (wing, keel, rudder, etc.) subject to a flow of a fluid (air, water, etc.) on either side. It designates the part opposite the direction of the steering, or in other words, the rear part considered in the direction of the flow. - Header: upper end of the sail which follows the upper contour of the sail. Lowering: consists of lowering the sail. - Hoisting: consists of raising the sail. - Rigging: all the fixed and moving parts of a boat, such as a sailboat, enabling its propulsion and maneuvers. - Sail receptacle: in addition to receiving the lowered sail, it can integrate other functions, such as taking up the tension forces provided by the sail, or housing other actuators, energy storage sensors and control module used to operate the sail. - Hydrodynamic drag: frictional force between the boat and the water. The higher the drag, the more the boat brakes. - Aerodynamic drag: component of the force experienced by a body in motion in a fluid which is exerted in the direction opposite to the direction of movement. According to the invention, the sail generates aerodynamic drag. - Aerodynamic lift: component of the force experienced by a body in motion in a fluid which is exerted perpendicular to the direction of movement. According to the invention, the sail generates aerodynamic lift. - Relative wind or apparent wind: vector sum of the wind created by the boat's own speed and the actual wind speed. - Aerodynamic resultant: vector sum of aerodynamic lift and aerodynamic drag. Prior art

[0003] Document WO 2017 / 221117A1 already discloses a sail propulsion element comprising an inflatable sail with a symmetrical profile. This propulsion element comprises an inflatable sail consisting essentially of two adjacent surfaces, substantially sealed and connected to each other around their periphery, thus forming at least one closed cavity. The element further comprises a conduit arranged between the inside and the outside of the cavity and means for injecting air into the cavity. This sail, once inflated, has a profile which remains permanently symmetrical, regardless of movement of the element, the direction or intensity of the wind. The sail of this document is constantly inflated during its use in navigation.

[0004] Unfortunately, such a flexible sail has the disadvantage of not having an inflation adapted to the different stages of its use, and in particular during the lowering and hoisting phases. Indeed, unlike a rigid sail, a flexible sail does not have a well-defined position during these handling stages (hoisting and lowering). During these stages it is important to keep the sail close to the axis of symmetry of the profile of the sail, so as to avoid the sail falling into the water or catching on an element close to it or not stacking properly to be able to store it compactly. Furthermore, it is important to maintain a low pressure inside the sail, during the lowering or reefing phase, to avoid it flapping, which could reduce its lifespan.

[0005] Finally, such a sail requires the presence of several air injection points, to its hoisting when folded, thus requiring adaptation of the structure of the fabric constituting the sail but without allowing rapid and safe deployment of the folded sail.

[0006] Also known from document WO2009043823A1 is a paraglider whose wing profile, which extends from the leading edge to the trailing edge, comprises a plurality of cells in the direction of the wingspan of the sail, spaced from each other by ribs. Such a paraglider comprises different downstream air inlet openings which serve to fill the first storage space during flight.

[0007] Unfortunately, such a sail comprises different categories of cells, including or not openings intended for the passage of air. These cells are not designed for the regular and continuous transmission of air from one cell to another, and this until the total deployment of the folded sail, but also for the ejection of air during partial or total lowering without the risk of seeing the sail fall into the water. Finally, an irregular distribution of the openings over the volume of the sail promotes the arrival of difficulty in the deployment of the sail due to the significant probability of blockage at the orifices, due to the fact that they will not be aligned to allow the passage of air. Summary of the invention

[0008] Also there remains the need to have an inflatable sail which, when lowering / inflating, transmits the air uniformly and regularly throughout the entire volume of the sail, while remaining correctly on its axis of symmetry along the mast, without fluttering or risk of being damaged, and which can be deployed in whole or in part repeatedly, manually or automatically. Furthermore, even in the deployed position, there is the need to be able to minimize the consumption of the inflation devices, as well as to be able to arrange them in the sail receptacle so as to simplify the supply of electrical energy.

[0009] The subject of the invention is a sail propulsion element comprising a mast, an inflatable sail consisting essentially of two adjacent surfaces which are substantially watertight and connected to each other around their periphery, thereby forming between them at least one closed cavity around the mast, said sail comprising an upper part, a lower part, a leading edge and a trailing edge, at least one air duct arranged between the inside and the outside of the cavity of the sail, at least one means for injecting air into said cavity, the sail once inflated having a profile which remains permanently symmetrical, regardless of the movement of said propulsion element, the direction or intensity of the wind, a head arranged on the upper part of the sail, a sail receptacle arranged between the leading edge and the trailing edge on the lower part of the sail.

[0010] The propulsion element according to the invention is characterized in that the sail comprises a plurality of cells in the direction of the span of the sail, each cell extending from the leading edge to the trailing edge, said cells being spaced apart by a rib made of a first flexible material which allows air to pass through, for example a 3D type structure.

[0011] It is interesting that the rib lets air pass through, minimizes the pressure loss but also allows the passage of forces.

[0012] The propulsion element according to the invention has the following various advantages.

[0013] Thanks to a continuous passage of air through each rib, the air circulates regularly and uniformly from one cell to another. The openwork ribs allow the internal pressure of the sail to be practically uniform throughout its entire volume, even if this device is only present in one place of the sail, making it possible to guarantee the precision of the profile of the sail and thus facilitating the transmission of aerodynamic forces, between the external part of the sail and the mast via the ribs. The presence of such ribs facilitates the automatic inflation and folding, after deflation of the sail, and in particular by using only fans present at the level of the sail receptacle, and this without any external intervention.The air-porous ribs replace and improve the air transmission previously made using multiple orifices arranged on the leading edge of the sail, which simplifies the power supply to the actuators. The fans can be replaced by other injection means, such as blowers or a pressurized air supply.

[0014] Preferably, each rib comprises a reinforcement zone delimited around the mast and made of a flexible composite material, reinforced so as to allow the passage of forces.

[0015] Preferably, the first and second flexible materials are woven materials having a different weave.

[0016] Preferably, the first flexible material comprises weaving meshes of approximately 2 to 4 mm.

[0017] Preferably, the second flexible material comprises weaving meshes of approximately 2 to 4 mm.

[0018] Preferably, the rib comprises a central strip which extends from the leading edge to the trailing edge.

[0019] Preferably, the central strip is made of the second flexible material.

[0020] Preferably, the central strip has a width ranging from 1 to 10 cm.

[0021] Preferably, the cells are spaced apart by a distance of between 0.8 and 2 m.

[0022] Preferably, point reinforcements are arranged regularly on the edge. attack.

[0023] Preferably, a guide line is arranged in the closed cavity of said sail, for the hoisting and lowering maneuvers of the sail, said guide line extending from the leading edge to the trailing edge of said sail, passing through the head and the sail receptacle, said guide line passing through the point reinforcements.

[0024] Preferably, when a guide line is present, it is made in one part, and is fixedly attached to the sail receptacle on the trailing edge and movable by furling on the leading edge, or, movable by furling to the sail receptacle on the trailing edge and fixed on the leading edge and in that the guide line is arranged along the headboard in a movable manner on at least one pulley between the trailing edge and the leading edge.

[0025] Preferably, when a guide line is present, it is made up of two parts, the first part on the trailing edge side is fixed or movable with a pulley on the head and movable by a winder on the receptacle, the second part on the leading edge side is fixed or movable with a pulley on the head and movable by a winder on the receptacle.

[0026] Another object of the present invention is a sail-powered or hybrid vehicle comprising at least one sail-powered element as mentioned above, a hull and a mast made integral with said hull while maintaining a degree of freedom in rotation. This vehicle is characterized in that the major part of the mast is arranged inside the inflatable sail cavity mentioned above.

[0027] Preferably, the mast is arranged inside the cavity of said inflatable sail.

[0028] Preferably, the sail is oriented according to the direction of the wind, and the direction vehicle operation manually or automatically.

[0029] By hybrid propulsion vehicle according to the invention, we mean sail propulsion coupled to another propulsion source such as for example propulsion by a propeller, driven by an electric or combustion engine, with energy storage of batteries, hydrogen (with a fuel cell), natural gas or fuel.

[0030] By vehicle is meant any machine comprising wheels or not, moving on land or on water. Description of the drawings

[0031] The invention will be described with the aid of the following figures, schematic and not necessarily to scale, and in which: - [Fig.l] represents a reminder of the different physical forces which are applied to a ship, for example of the sailboat type with an engine, and in particular the projection of the resulting aerodynamic force; - [Fig.2] represents a schematic front view of the fully hoisted sail propulsion element, according to the invention; - [Fig.3] represents a schematic front view of the sail propulsion element partially comprising ribs; - [Fig.4] represents an enlarged schematic view of the portion of the sail propulsion element according to the invention, comprising ribs; - [Fig.5] represents a schematic front view of the fully folded sail propulsion element according to the invention; - [Fig.6] represents a 3D schematic view of a rib.

[0032] Before explaining in more detail the sail propulsion element, object of the present invention, with the aid of the figures cited, a reminder of some definitions of hydrodynamics and aerodynamics is set out below.

[0033] A sail-powered vehicle, hereinafter referred to as a sailboat or ship, is in contact with the air and with the water. From a physical point of view, the predominant factors are the hydrodynamic and aerodynamic forces which are exerted on the hull, the sails and the appendages (daggerboards, keel, rudder, propeller).

[0034] As shown in [Fig.l], the aerodynamic force (or sail thrust) results from the deflection of the air by at least one sail. The aerodynamic force is relative to the position and surface of the sail and to the position and strength of the relative wind. The drag force is in the direction of the relative wind, the lift force is in the perpendicular direction of the relative wind, it is not always perpendicular to the sail. For example, at 0°, a symmetrical profile has no lift due to the fact that the air travels strictly the same distance on the extrados and the intrados. At this moment, it only generates drag.

[0035] The aerodynamic force, generated by the sail, can also be broken down in the frame of reference of the boat, and not in that of the sail, to be composed of the sail propulsive force (which is in the axis of travel of the boat) and a drift force (perpendicular to the axis of the boat) which can induce heeling (transverse inclination of a boat caused by an external phenomenon such as the wind).

[0036] The hydrodynamic force results from the friction of the water on the hull and the drift or keel and the various submerged appendages. Its direction depends on the aerodynamic force to which it opposes, the propulsive force in hybrid mode, the state of the sea and the sea currents. The longitudinal component is called hydrodynamic drag, and the transverse component is called drift lift or anti-drift force or hydrodynamic lift. The direction and intensity of the hydrodynamic force does not depend only on the aerodynamic force. For a building (boat) operating in hybrid mode (wind and other energy), the hydrodynamic force will depend strongly on the speed of the building generated by thermal propulsion or electrical for example, the state of the sea and the ocean currents.

[0037] When the sail force is greater than the hydrodynamic force, the boat accelerates. When the sail force is less than the hydrodynamic force, the boat slows down. Furthermore, if the aerodynamic force is greater but directed towards the rear of the boat, the latter will slow down. If the hydrodynamic force is in the direction of travel of the boat (because there is a strong current), the boat will accelerate.

[0038] It is by optimizing the sail adjustment that the sailboat will achieve its maximum performance in terms of sail thrust in the direction of travel. Indeed, it is the optimization of the angle of the sail in relation to the relative wind and the direction of the boat, as well as the adjustment of the surface of the sail which will allow the boat to achieve the maximum of its sail propulsion in the axis of the boat. There can be an additional adjustment by playing on the internal pressure of the sail. This thus makes it possible to increase the speed of the boat or on the contrary to maintain the same speed while reducing the consumption of other energies, by favor of the sail propulsion.

[0039] [Fig.l] takes up each of the preceding names with a reference specific to it listed below: a: Lift force b: Drag force c: Aerodynamic resultant force d: Aerodynamic thrust force (in the axis of the ship) e: Aerodynamic drift force f: Relative wind g: Relative angle between wing and boat axis (e.g.: 15°) h: Relative wind angle and boat axis (e.g.: 30°) i: Propeller propulsive force j: Hull k: Sail 1: Mast m: Center of aerodynamic thrust n: Propeller o: Sensor on fixed part (hull reference) p: Sensor on moving part (sail reference). The information given by [Fig.l] allows to pass from the data sensors coming from the hull reference frame, to the data sensors coming from the sail reference frame, and vice versa.

[0040] Fig. 2 represents the propulsion element of general reference 1 according to the invention mounted on a hull 2 ​​of a boat, sailboat type, using a self-supporting mast 3. The connection of the mast 3 with the hull is carried out using a support (not re presented) intended to recover the efforts of physical forces. The efforts are measured at the level of the support or the mast itself. The sail comprises two adjacent surfaces 4a and 4b connected to each other so as to form a closed cavity. Each surface 4a, 4b can be made of a material having several layers, so as to satisfy the different characteristics, such as mechanical resistance, waterproofing, against fire, against UV.

[0041] The sail 1 comprises several cells 5 distributed over the entire height of the sail 1 in the spanwise direction. Each cell 5 extends from the leading edge 6 to the trailing edge 7 (as shown in [Fig.5]). The cells 5 are spaced approximately 1 m apart from each other.

[0042] As shown in [Fig.3], the cells 5 are separated from each other by a rib 8. Each rib 8 is made of a first material, for example, woven consisting of a warp mesh with wefts of about 3 mm, the yarn can be coated with a compound such as PVC. This type of 3D weaving guarantees the correct passage of air even when the sail is folded, in stowed mode.

[0043] This first material which can be woven is fixed to the sail by adhesive means, by sewing or welding or any other means allowing the assembly to be secured. No coating is then carried out, because it would block the pores of the material, and prevent the air from circulating correctly.

[0044] It is also possible to use as the first woven material a fabric which makes a gradual transition between the material constituting the external layer of the sail 1 and the first woven material of the rib 8. Filament membrane can also be used.

[0045] As shown in [Fig.4], each cell 5 is separated by a rib 8. During hoisting / lowering the air, managed by the fans, or any other inflation means, arranged, for example, in the sail receptacle, is blown or sucked into the cavity of the sail. The air passes through the ribs 8 (arrows 9) from top to bottom or from bottom to top (depending on whether the sail is inflated or deflated), thus allowing a substantially uniform distribution of internal pressure of the sail 1, whether for a fully unfurled sail, for a sail whose sail area has been reduced by reefing or at the start of inflation while the ribs are stacked.

[0046] The construction of the ribs 6 also makes it possible to guarantee the absorption of forces linked to the internal pressure of the sail 1, as well as to be able to transmit the aerodynamic pressure exerted on the profile of the sail 1 towards the mast 3. The ribs in fact absorb the internal pressure of the sail, and also allow the transmission of aerodynamic forces.

[0047] As symbolized (arrow 10), the internal pressure of the sail presses against the wall of the sail.

[0048] The particular choice of the first woven material according to the invention of the ribs 8, and in particular the orientation of the threads which constitute this material, makes it possible to correctly carry out the passage of the aerodynamic forces from the sail to the mast 3. A limited passage of air around the mast 3 is not penalizing. The most important thing is to allow the air to pass over the front part of the rib (towards the leading edge), and over the rear part of the rib (towards the trailing edge).

[0049] The first advantage of using the first material allowing air to pass through and absorbing the forces according to the invention, unlike the point orifices distributed over the surface of the sail, is to avoid partial or total obstruction of one or more orifices, which would significantly hinder the correct circulation of air in the cavity of the sail 1.

[0050] The second advantage is that it allows for a significant reduction in pressure losses while maintaining sufficient resistance for the transmission of forces, thus reducing the power of the inflation devices, and thus energy consumption.

[0051] A final advantage of this first material is the possibility of eliminating the fans in the leading edge. The fans arranged in the sail receptacle are sufficient for the majority of maneuvers requiring the air to be blown in or removed.

[0052] As shown in [Fig.5], the cells 5 allow air (arrow 9) to pass upwards onto the element according to the invention when fully folded in order to hoist the sail 1.

[0053] The schematic representation of [Fig.6] shows a reinforcement zone 11 delimited around the mast 3. This zone represents approximately a surface area of ​​7.5m2. It is made of a second material different from the first material, which can for example be made with the same material but with a different angle for example: first material having a weaving angle of 0 and 90° and second material having an angle of + / -45° relative to the first material.

[0054] This second material is defined by a mesh dimension of approximately 3 mm.

[0055] [Fig.5] further shows the presence of a strip 12 made of a material of reinforcement. This strip 12 has a width of approximately 80mm.

[0056] Its role is to allow a distribution of forces and to limit wear by abrasion at the places where the different ropes pass, such as those of the reefing lines or the guide line.

[0057] Point reinforcements (not shown) may be arranged regularly on the leading edge and / or the trailing edge at the level of the ribs 6.

[0058] Example The following example is given for illustration purposes only and is in no way limiting. The following table lists different possible situations. Cargo Sailboat Boat length (meter) 13 140 Number of sails 1 8 Sail rib - polyester (g / m2) 220 240 Sail outer layer coated polyester (g / m2) 110 160 Sail height (meter) 17 40 Greatest sail length (meter) 8 17 Greatest sail width (meter) 1.8 3.5 Sail area (m2) 100 500 Number of cells 30 35

[0059] The outer layer of the sail, also called bodywork, is made of a fabric comprising an outer part in contact with the outside air, and an inner part. This fabric can be made of a polyester woven fabric coated with polyurethane. The weight of this fabric can be 180 g / m2 for a sail area of ​​approximately 100m2.

[0060] The upper part of the sail can be attached using self-gripping strips, such as Velcro. The connections between the outer parts of the sail and the ribs (internal connections), as well as the connections between the components of the outer part, can be made by welding or gluing or any other means of connection (zipper for example) making it possible to guarantee, at the same time, a sufficiently low level of permeation compatible with the existing inflation system and also to guarantee the passage of forces.

Claims

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6. Claims Sail propulsion element comprising: a. a mast (3), b. an inflatable sail (1) consisting essentially of two adjacent surfaces (4a, 4b) which are substantially watertight and connected to each other around their periphery, thereby forming between them at least one closed cavity around the mast (3), said sail comprising an upper part, a lower part, a leading edge (6) and a trailing edge (7), c. at least one air duct arranged between the inside and the outside of the sail cavity, d. at least one means for injecting air into said cavity, the sail once inflated having a profile which remains permanently symmetrical, regardless of the movement of said propulsion element, the direction or intensity of the wind, e. a headboard placed on the upper part of the sail f. a sail receptacle arranged between the leading edge (6) and the trailing edge (7) on the lower part of the sail, characterized in that the sail comprises a plurality of cells (5) in the spanwise direction of the sail, each cell (5) extending from the leading edge (6) to the trailing edge (7), said cells (5) being spaced apart by a rib (8) made of a first flexible material which allows air to pass through. Element according to claim 1, in which each rib (8) comprises a reinforcement zone (11) delimited around the mast (3) and made of a second flexible composite material. An element according to claim 2, wherein the first and second flexible materials are woven materials having a different weave. An element according to either of claims 1 or 3, wherein the first flexible material comprises weave meshes of approximately 2 to 4 mm. An element according to either of claims 2 or 3, wherein the second flexible material comprises weave meshes of approximately 2 to 4 mm. The element of claim 1, wherein the rib comprises a central strip extending from the leading edge to the trailing edge.

7. An element according to claims 2 and 6, wherein the central strip is constituted by the second flexible material.

8. Element according to one of claims 5 or 6, in which the central strip has a width ranging from 1 to 10 cm.

9. An element according to claim 1, wherein the cells are spaced apart by a distance of between 0.8 and 2m.

10. Element according to one of the preceding claims, in which point reinforcements are arranged regularly on the leading edge.

11. An element according to claim 10, wherein a guide line is arranged in the closed cavity of said sail, for the hoisting and lowering maneuvers of the sail, said guide line extending from the leading edge to the trailing edge of said sail, passing through the head and the sail receptacle, said guide line passing through the point reinforcements.

12. Sail-powered or hybrid vehicle comprising at least one element according to one of the preceding claims, a hull and a mast secured to said hull while maintaining a degree of freedom in rotation, characterized in that the major part of the mast is arranged inside the cavity of said inflatable sail.

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

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