Wind-assisted propulsion device

Abstract

The invention relates to a wind-assisted propulsion device (1) comprising: - first and second sails (3, 4), which are opposite one another and are interconnected so as to share a trailing edge (BF); - a tubular inflatable casing (5) extending along a longitudinal axis (Z'-Z), and comprising: a leading edge (BA), intended to face the wind (V), and defining a camber line (L1) together with the trailing edge (BF); a junction zone (6), in which the first and second sails (3, 4) are joined, having an angular position (Ω) that varies on the basis of the camber line (L1); wherein the tubular casing (5) delimits a closed chamber filled with a fluid (F), preferably air, exerting a pressure on the inside of the tubular casing (5), the pressure being different from atmospheric pressure and being determined on the basis of a wind speed (V) such that the leading edge (BA) is kept under tension.

Description

[0001] V-PROPULSION DEVICE

[0002] technical field

[0003] The invention relates to the technical field of sail propulsion devices.

[0004] The invention finds its application particularly in the sail propulsion of ships.

[0005] State of the art

[0006] A sail propulsion device known from the prior art, notably from documents WO 98 / 26982 A1 and US 3,391,668 A, comprises:

[0007] - the first and second sails, opposite, and connected to each other in such a way as to share a trailing edge intended to be fixed to the clew of a ship;

[0008] - a tubular, inflatable envelope, extending along a longitudinal axis, and comprising: first and second attachment zones opposite each other along the longitudinal axis, intended to be attached respectively to the tack point and the halyard point of a ship; a leading edge, intended to face a wind, and defining with the trailing edge a line of camber which changes according to a wind direction.

[0009] Such a state-of-the-art sail propulsion system is not entirely satisfactory because the tubular envelope, inflated by the dynamic pressure exerted by the wind, may not be high enough to maintain a stable leading edge shape under certain sailing conditions. Furthermore, the dynamic pressure exerted by the wind may be too high, preventing some areas near the trailing edge from maintaining a stable shape under certain sailing conditions.

[0010] Description of the invention

[0011] The invention aims to remedy, in whole or in part, the aforementioned drawbacks. To this end, the invention relates to a sail propulsion device for equipping a vessel having a halyard point, a tack point, and a clew point, the device comprising:

[0012] - the first and second sails, opposite, and connected to each other in such a way as to share a leading edge intended to be fixed at the clew;

[0013] - a tubular, inflatable envelope extending along a longitudinal axis, and comprising: first and second attachment zones opposite each other along the longitudinal axis, intended to be attached respectively to the tack point and the halyard point; a leading edge, intended to face a wind, and defining with the trailing edge a line of camber which changes according to a wind direction; a joining zone, on which the first and second sails are joined, having an angular position defined with respect to the leading edge and the longitudinal axis which varies according to the line of camber; a device in which the tubular envelope delimits a closed chamber filled with a fluid, preferably air, exerting a pressure inside the tubular envelope, the pressure being different from atmospheric pressure and determined according to a wind speed so that the leading edge is kept under tension.

[0014] Thus, such a sail propulsion device according to the invention makes it possible to maintain a stable shape of the leading edge thanks to the following characteristics:

[0015] (i) the tubular envelope delimits a closed chamber (and not open compared to the prior art) filled with a fluid;

[0016] (ii) the pressure exerted by the fluid inside the chamber is determined as a function of a wind speed (related to certain navigation conditions) so as to maintain tension on the leading edge (and not due to the dynamic pressure exerted directly by the wind during navigation, as in the prior art).

[0017] Furthermore, and surprisingly, the internal pressure exerted by the fluid and applied to the tubular envelope plays a crucial role in maintaining the geometric stability of the entire device, not just the leading edge. Specifically, this internal pressure counteracts the stresses created by aerodynamic forces related to wind speed, which could deform the tubular envelope if the internal pressure is too low.

[0018] In other words, the tubular envelope defines a closed chamber filled with a fluid, preferably air, exerting pressure inside the envelope. This pressure is different from atmospheric pressure and determined as a function of wind speed, so that the leading edge remains under tension and the tubular envelope, subjected to aerodynamic forces, maintains geometric stability (shape retention without obvious deformation) during navigation. Contrary to the prior art, the internal pressure is determined as a function of wind speed, and simply having an internal pressure higher than atmospheric pressure is insufficient to stabilize only the leading edge.

[0019] Furthermore, the junction zone of the tubular envelope, where the first and second webs are joined, has an angular position (defined relative to the leading edge and the longitudinal axis of the tubular envelope) that varies according to the camber line, which allows the web length to vary by:

[0020] - the extrados, between the leading edge and the trailing edge), and of

[0021] - the intrados, between the leading edge and the trailing edge.

[0022] The length of the upper surface (extrados) can be calculated by adding the length of the first sail between the trailing edge and the joining point, and the length of the second sail between the joining point and the leading edge. The length of the lower surface (intrados) can be calculated by adding the length of the second sail between the trailing edge and the leading edge. This variation in sail length allows for adjustments to the airfoil's camber, the airfoil's thickness (i.e., the volume between the first and second sails), and the airfoil's camber to be reversed depending on the wind direction without the lower surface sail being slack.

[0023] The sail propulsion device according to the invention may include one or more of the following characteristics.

[0024] According to one feature of the invention, the device includes a control circuit configured to regulate the pressure exerted by the fluid inside the tubular envelope as a function of wind speed.

[0025] Thus, one advantage provided is the ability to adjust the pressure exerted by the fluid inside the tubular envelope under real navigation conditions, to maintain tension on the leading edge.

[0026] According to one feature of the invention, the first and second sails are connected to each other in such a way as to delimit a volume open at their base with the tubular envelope, the open volume allowing an entry of air at atmospheric pressure.

[0027] Thus, one advantage provided is ease of implementation. The fact that the volume is open at the base of the first and second sails prevents the atmospheric pressure of the air intake from being affected by the overpressure or underpressure exerted on the first and second sails depending on their position relative to the wind direction. The sail experiencing overpressure is called the lower surface (intrados), while the sail experiencing underpressure is called the upper surface (extrados). The lower surface is the sail closest to the prevailing wind. The upper surface is the sail furthest from the prevailing wind. The air flowing over the upper surface is accelerated, creating a low-pressure zone through the Venturi effect, which is the primary cause of the lift propelling the vessel. According to one feature of the invention:

[0028] - the first and second sails are connected to each other in such a way as to delimit a closed enclosure with the tubular envelope;

[0029] - the closed enclosure is filled with a fluid, preferably air, exerting a controlled pressure inside the closed enclosure so as to modulate a volume of the closed enclosure.

[0030] Thus, one advantage is the ability to control the volume between the first and second sails under real sailing conditions in order to optimize laminar wind flow. The fact that the sail junction zone has an angular position (defined relative to the leading edge and the longitudinal axis) that can vary depending on the camber line and the volume between the first and second sails improves the stability of the shape of areas near the trailing edge in the event of high dynamic pressure exerted by the wind on the sails, or in the event of a tack that reverses the camber line.

[0031] After navigation, the closed enclosure can be deflated to allow for compact winding of the device.

[0032] According to one feature of the invention, the control circuit is configured to regulate the pressure exerted by the fluid inside the closed enclosure.

[0033] Thus, one advantage provided is the use of a single control circuit to regulate both the fluid in the tubular envelope and the fluid in the closed enclosure.

[0034] According to one feature of the invention:

[0035] - the first and second sails are connected to each other in such a way as to delimit a volume with the tubular envelope;

[0036] - a dynamic scoop is arranged to capture an airflow at atmospheric pressure and to redirect said airflow in such a way as to modulate the volume.

[0037] Thus, one advantage provided is the ability to capture a dynamic overpressure from the aerodynamic lift of the airfoil and transfer it to the volume between the first and second wings. Furthermore, the dynamic scoop automatically captures this dynamic overpressure, regardless of the camber line. For example, when the camber line is reversed, the dynamic scoop changes sides due to the reversal of the pressure difference between the lower and upper surfaces. According to a feature of the invention, the tubular envelope is free to rotate about its longitudinal axis.

[0038] One advantage of this is the ease with which the angular position of the junction zone can be adjusted when the camber line changes due to a shift in wind direction. In other words, the sail orientation can adapt to changes in wind direction without excessive stress.

[0039] According to one feature of the invention, the device includes drive means arranged to rotate the tubular casing around an axis of rotation passing through the first and second fixing zones.

[0040] Thus, one advantage provided is the ability to adjust the axis of rotation of the tubular envelope during navigation in order to adapt to specific conditions to improve the stability of the volume extending between the first and second sails.

[0041] According to one feature of the invention, the axis of rotation passing through the first and second fixing zones and the longitudinal axis are coincident, or parallel, or intersecting.

[0042] Thus, one advantage provided is the ability to modify the position of the axis of rotation which has an impact on the torque resulting from the tensions exerted by the first and second sails on the tubular envelope under sailing conditions.

[0043] According to one feature of the invention, the device includes adjustment means arranged to adjust the angular position of the junction zone.

[0044] One advantage of this design is the ability to modify the volume between the first and second sails, for example by sliding them around the tubular envelope using a rope designed to twist the joint between the first and second sails. This allows the variation in angle of attack to windage to be adjusted according to the height of the joint area.

[0045] According to one feature of the invention, comprising a zipper arranged to connect the first and second sails together at the junction area or to connect the first and second sails together along the edge of the sail.

[0046] Thus, one advantage provided is the simplicity and speed of setting up the device on a ship, for example around a forestay. According to one feature of the invention, the device comprises a spar having first and second opposing ends, the first end being connected to the edge of the stern, the second end being connected to the second attachment point of the tubular casing.

[0047] Thus, one advantage provided is to improve the stability of the device by maintaining a sufficient area for the surface defined by the upper contour of the first and second sails.

[0048] The invention also relates to a vessel comprising:

[0049] - a mast with a halyard point;

[0050] - a tack point and a listening point;

[0051] - a device according to the invention, the first and second fixing zones of the tubular envelope being respectively fixed to the tack point and the halyard point, the first and second sails being fixed to the clew point.

[0052] Definitions

[0053] - By "leading edge", we mean a front part in the direction of the airflow, facing the wind.

[0054] - By "tail edge", we mean a rear part in the direction of the airflow, opposite to the leading edge.

[0055] - By "line of camber," we mean the curve passing between the first and second sails (intrados and extrados, or vice versa), that is, passing through the points located halfway between the intrados and extrados. The intrados is the sail that is closest to the prevailing wind. The extrados is the sail that is furthest from the prevailing wind.

[0056] - The expression "line of camber changing according to a wind direction" does not mean that the wind direction is the only parameter changing the line of camber.

[0057] - The term "tubular" should be understood as a tube shape in the mathematical sense, not necessarily having a constant section along the longitudinal axis of the envelope, covering in particular a cylindrical shape, a conical shape, or a truncated conical shape.

[0058] - The term "fixed" should be understood as attached directly or indirectly (via an intervening element) to the corresponding point (halyard, sheet, tack).

[0059] The term "junction zone" refers to an area of ​​the tubular envelope where the first and second walls are joined. In other words, the junction zone is the area of ​​the tubular envelope where the first and second walls are connected. This term does not necessarily imply that the first and second walls are permanently fixed to the tubular envelope at the junction zone. In other words, this term does not necessarily imply that the first and second walls are mechanically attached to the tubular envelope at the junction zone. Indeed, it is possible to design a connection between the walls and the tubular envelope that allows for relative movement of the walls with respect to the tubular envelope at the junction zone.

[0060] - By "determined as a function of wind speed," we mean that the pressure exerted by the fluid inside the tubular envelope can be calculated (estimated, simulated) from a physical principle, experiments, or numerical simulations involving wind speed. One physical principle that can be used is the maximum dynamic wind pressure exerted on the external surface of the tubular envelope. The mathematical formulation of this physical principle is notably developed in NACA (National Advisory Committee for Aeronautics) report no. 563 by R.M. Pinkerton, entitled "Calculated and measured pressure distributions over the midpan section of the NACA 4412 airfoil," and dated 1936.Besides wind speed, other parameters can influence the calculation of the pressure exerted by the fluid inside the tubular envelope, such as fluid velocity, fluid density, and the geometry of the device (tubular envelope and sails). The term "determined" does not necessarily mean that the pressure is fixed, i.e., constant over time. Indeed, with a control circuit, the pressure can be regulated during navigation and therefore varies while the device is in use. The term "determined" also encompasses the fact that the pressure can be predetermined (in this case, fixed), i.e., determined before the device is used for certain navigational conditions involving a typical wind speed.

[0061] Brief description of the drawings

[0062] Other features and advantages will become apparent in the detailed description of different embodiments of the invention, the description being accompanied by examples and references to the accompanying drawings.

[0063] Figure 1 is a schematic top view, illustrating a device according to the invention subjected to a first wind direction.

[0064] Figure 2 is a partial schematic top view, enlarged to scale, illustrating a front portion of the device according to the invention.

[0065] Figure 3 is a schematic top view illustrating a device according to the invention with zero wind incidence. The camber line is then a straight line coinciding with the chord line. Figure 4 is a schematic view similar to Figure 1, illustrating a reversal of the wind direction and a reversal of the camber line.

[0066] Figure 5 is a schematic top view of a device according to the invention, illustrating a zipper arranged to connect the first and second sails together on the junction area.

[0067] Figure 6 is a schematic top view of a device according to the invention, illustrating a zipper arranged to connect the first and second sails together along the edge of the slit.

[0068] Figure 7 is a schematic top view, illustrating a distribution of the dynamic pressure exerted at the periphery of a device according to the invention, the tubular envelope not being shown.

[0069] Figure 8 is a schematic perspective view of a device according to the invention, illustrating an adjustment of the angular position of the junction zone.

[0070] Figure 9 includes three schematic top views of a device according to the invention, illustrating the influence of the angular position of the junction zone on the volume between the first and second sails for a given wind direction.

[0071] Figure 10 is a schematic perspective view of a device according to the invention equipping a ship, and fitted with a yard.

[0072] Figure 11 is a partial schematic perspective view, at an enlarged scale, of a device according to the invention equipping a ship, and fitted with a yard.

[0073] Figure 12 is a schematic perspective view of a device according to the invention.

[0074] Figure 13 is a schematic top view, illustrating a device according to the invention equipped with a scoop.

[0075] Figure 14 is a partial schematic perspective view of the device according to the invention passing through axis AA of figure 13.

[0076] It should be noted that the drawings described above are schematic, and are not necessarily to scale for the sake of readability and to simplify their understanding.

[0077] Detailed description of the implementation methods

[0078] Identical elements or elements performing the same function will bear the same reference numerals for the different embodiments, for the sake of simplification. One object of the invention is a sail propulsion device 1 for equipping a vessel 2 having a halyard point D, a tack point A, and a sheet point E, the device 1 comprising:

[0079] - the first and second sails 3, 4, opposite, and connected to each other in such a way as to share a trailing edge BF intended to be fixed to the clew point E;

[0080] - a tubular envelope 5, inflatable, extending along a longitudinal axis Z'-Z, and comprising: first and second attachment zones opposite each other along the longitudinal axis Z'-Z, intended to be attached respectively to the tack point A and the halyard point D; a leading edge BA, intended to face a wind V, and defining with the trailing edge BF a camber line L1 which changes according to a wind direction V; a joining zone 6, on which the first and second sails 3, 4 are joined, having an angular position Q defined with respect to the leading edge BA and the longitudinal axis Z'-Z varying according to the camber line L1;device 1 in which the tubular envelope 5 delimits a closed chamber filled with a fluid F, preferably air, exerting a pressure inside the tubular envelope 5, the pressure being different from atmospheric pressure and determined as a function of a wind speed V so that the leading edge BA is kept under tension.;

[0081] First and second sails

[0082] The first and second sails, 3 and 4, are opposite each other. In other words, the first and second sails, 3 and 4, face each other. The first and second sails, 3 and 4, can be described as the lower and upper surfaces (and vice versa) depending on the wind direction V, by analogy with the surfaces of an airplane wing. The lower surface (intrados) is the sail, 3 and 4, that is closest to the prevailing wind V. This sail, 3 and 4, is under higher relative pressure because the air flowing over it tends to slow down, creating an area of ​​high pressure. The upper surface (extrados), conversely, is the sail, 3 and 4, that is furthest from the prevailing wind V. The air flowing over this sail, 3 and 4, is accelerated, creating an area of ​​low pressure. The low-pressure area and the high-pressure area create a lift force which allows the propulsion of a ship. It should be noted that the low-pressure area at the extrados contributes more to the lift than the high-pressure area at the intrados.

[0083] The first and second sails 3, 4 are joined together so as to share a trailing edge BF intended to be attached to a clew E of a vessel 2. Advantageously, the first and second sails 3, 4 have a connection between their leeches designed to slide along the trailing edge BF. The sliding connection is attached to a halyard point D of a vessel 2. The sliding connection is attached to a clew point E of a vessel 2, preferably by a ball-and-socket joint. The fact that the sliding connection shares a halyard point D and a clew point E results in the translation between the leeches of the first and second sails 3, 4 following an axis perpendicular to the longitudinal axis Z'-Z, and parallel to the first and second sails 3, 4 at their leeches. The sliding connection can be sealed.According to one embodiment, the sealing of the connection can be ensured by a pleat made in a flexible and stretchable fabric adapted so as not to disturb the kinematics of the first and second sails 3, 4. An advantage of such a sliding connection is to allow a twist of the first and second sails 3, 4, without the formation of vertical folds on the extrados, which would result in deforming the trailing edge BF, and reducing the aerodynamic performance of the device 1.

[0084] The first and second walls 3, 4 can be connected to each other to define a volume 7 open at their base to the tubular envelope, this open volume 7 allowing the ingress of air at atmospheric pressure. Alternatively, the first and second walls 3, 4 are connected to each other to define a closed enclosure to the tubular envelope. The closed enclosure is filled with a fluid, preferably air, exerting a controlled pressure inside the closed enclosure so as to modulate a volume 7 of the closed enclosure.

[0085] The first and second layers 3 and 4 can be made from a woven material (e.g., polyester) or a laminate (e.g., Mylar). Aromatic polyamide (aramid), polyethylene (e.g., high molecular weight), and carbon fibers can also be used. The first and second layers 3 and 4 can be manufactured using traditional methods: sewing, bi-radial / tri-radial joining, welding, lamination, vacuum infusion of strip assembly, mold curing, etc. By way of non-limiting example, the first and second layers 3 and 4 can be joined together by sewing, heat sealing, welding, etc.

[0086] Tubular casing

[0087] The tubular casing 5 is inflatable. In other words, the tubular casing 5 is made of a flexible material that can be filled with a fluid F, preferably air. The flexible material is designed to withstand the pressure exerted by the fluid F. By way of non-limiting examples, the flexible material can be a woven fabric (e.g., polyester) or a laminate (e.g., Mylar). Aromatic polyamide (aramid), polyethylene (e.g., high molecular weight), and carbon fibers can also be used. The tubular casing 5 can be manufactured using traditional methods: sewing, bi-radial / tri-radial assembly, welding, lamination, vacuum infusion of strip assembly, mold curing, etc.

[0088] When the tubular envelope 5 is deflated, the winding of the first and second sails 3, 4 around the tubular envelope 5 is thus facilitated for their storage, and can be carried out using a sail furler.

[0089] The tubular envelope 5 extends along a longitudinal axis Z'-Z, that is, along the length of the tubular envelope 5. The tubular envelope 5 has first and second attachment points along the longitudinal axis Z'-Z, intended to be attached respectively to the tack point A and the halyard point D. When the first and second attachment points are attached directly to the tack point A and the halyard point D, the longitudinal axis Z'-Z corresponds to the axis defined by the tack point A and the halyard point D. According to a first geometric configuration (as in the case of a mainsail), the tack point A and the halyard point D can define a vertical axis. According to a second geometric configuration (as in the case of a jib), the tack point A and the halyard point D can define an oblique axis.

[0090] The tubular envelope 5 has a leading edge BA, designed to face a wind V. The trailing edge BF (shared by the first and second sails 3, 4) and the leading edge BA define a camber line L1 which changes according to the wind direction V. More precisely, the camber line L1 extends between the leading edge BA and the trailing edge BF, and the curvature of the camber line L1 is defined by the curve passing between the first and second sails 3, 4, that is to say, passing through the points located midway between the first and second sails 3, 4. The leading edge BA and the trailing edge BF also define a chord line L2 which is the straight line connecting the leading edge BA to the trailing edge BF.

[0091] The tubular shell 5 has a joining zone 6, to which the first and second sails 3, 4 are joined. The joining zone 6 has an angular position Q defined relative to the leading edge BA and the longitudinal axis Z'-Z of the tubular shell 5. The angular position Q of the joining zone 5 varies according to the camber line L1. The first and second sails 3, 4 can be connected to the tubular shell 5 at the joining zone 6 by a textile membrane arranged on the tubular shell 5. Alternatively, the first and second sails 3, 4 can be connected to the tubular shell 5 at the joining zone 6 by a rope providing a floating connection between the first and second sails 3, 4 and the tubular shell 5.

[0092] The tubular casing 5 defines a closed chamber filled with a fluid F, preferably air, exerting pressure inside the tubular casing 5. The pressure exerted by the fluid F is different from atmospheric pressure and is determined as a function of a wind speed V such that the leading edge BA is kept under tension. The tubular casing 5 advantageously includes an air chamber arranged within it to retain the pressure exerted by the fluid F within the tubular casing 5. By way of non-limiting example, the air chamber may be made of thermoplastic polyurethane. The tubular casing 5 may be equipped with a zipper for inserting and removing the air chamber from the tubular casing 5. The tubular casing 5 may be inflated via a fitting 50, preferably equipped with a valve.

[0093] In a first embodiment, the tubular casing 5 is free to rotate about the longitudinal axis Z'-Z. In a second embodiment, the device includes drive means arranged to rotate the tubular casing 5 about an axis of rotation passing through the first and second fixing zones. The axis of rotation passing through the first and second fixing zones and the longitudinal axis Z'-Z may coincide, be parallel, or intersect. The second embodiment is not necessarily incompatible with the first embodiment. Indeed, it is possible to provide a mechanical transmission system (e.g., freewheel, clutch) configured to interrupt the rotational drive so that the tubular casing 5 is free to rotate about the longitudinal axis Z'-Z.

[0094] Regulation circuit

[0095] Device 1 advantageously includes a control circuit configured to regulate the pressure exerted by the fluid F inside the tubular casing 5 as a function of the wind speed V. To this end, the control circuit may include at least one pressure sensor (e.g., a strain gauge) arranged inside the tubular casing 5 to measure the pressure exerted by the fluid F. It is also possible to include at least one volume sensor. The control circuit may include at least one pump arranged to ensure the circulation of the fluid F within the control circuit.

[0096] When the first and second walls 3, 4 are connected to each other to define a closed enclosure with the tubular casing 5, the control circuit is advantageously configured to regulate the pressure exerted by the fluid inside the closed enclosure. For this purpose, the control circuit may include at least one pressure sensor (e.g., a strain gauge) arranged inside the closed enclosure to measure the pressure exerted by the fluid. A volume sensor may also be included. The control circuit may include at least one feedback loop configured to control the pressure value measured by the sensors against a setpoint.

[0097] The control circuit may include at least one valve arranged to regulate the quantity of fluid F inside the tubular casing. Similarly, the control circuit may include at least one valve arranged to regulate the quantity of fluid inside the closed enclosure. The valve(s) may advantageously be remotely controlled (e.g., by radio) to inflate / deflate the tubular casing 5 and / or the closed enclosure.

[0098] Angular position adjustment

[0099] The device advantageously includes adjustment means arranged to adjust the angular position Q of the junction zone 6. The adjustment means are advantageously configured to slide the first and second sails 3, 4 around the tubular envelope 5.

[0100] According to one embodiment, the adjustment means include a rope system designed to twist the junction between the first and second sails 3, 4. It is also possible to provide an adjustable tension system (e.g. straps, pulleys, tensioners) designed to twist the junction between the first and second sails 3, 4.

[0101] A twist is applied along the junction between the first and second sails 3, 4 in order to twist the junction, for example by pulling the ends of the junction asymmetrically.

[0102] Zipper(s)

[0103] Device 1 advantageously includes a zipper 8a arranged to connect the first and second sails 3, 4 together on the junction area 6. Device 1 advantageously includes a zipper 8b arranged to connect the first and second sails 3, 4 together along the trailing edge BF.

[0104] Yard

[0105] Device 1 advantageously comprises a spar 9 having opposing first and second ends 90, 91. The first end 90 of the spar 9 is connected to the trailing edge BF, more precisely to the upper part of the trailing edge BF. The second end 91 of the spar 9 is connected to the second attachment point of the tubular casing 5. The spar 9 is connected to the halyard point D of the vessel 2. More specifically, the spar 9 may include a connecting element 92 mounted to slide between the first and second ends 90, 91, so as to modify the distribution of tension between the tubular casing 5 and the trailing edge BF. The connecting element 92 is fixed to the halyard point D of the vessel 2. The spar 9 may be made in the form of a statically determinate beam having three ball-and-socket joints.

[0106] Scoop

[0107] According to an embodiment illustrated in Figures 13 and 14, the device 1 advantageously comprises a dynamic scoop 10 arranged to capture an airflow at atmospheric pressure and to redirect said airflow so as to modulate the volume 7 between the first and second wings 3, 4. The dynamic scoop 10 is arranged to capture a dynamic overpressure of the aerodynamic lift of the airfoil in order to impart it to the volume 7 between the first and second wings 3, 4. Furthermore, the dynamic scoop 10 automatically captures the dynamic overpressure, regardless of the camber line L1. For example, during a reversal of the camber line L1, the dynamic scoop 10 changes sides due to the reversal of the pressure difference between the lower and upper surfaces.

[0108] The dynamic scoop 10 is advantageously positioned at the base of the first and second sails 3, 4. The aerodynamic scoop 10 can be made from a flexible material, such as fabric, without any particular restriction as to the nature of this material, provided that it possesses two essential functional characteristics. First, the material must have sufficient flexibility to allow it to tilt or change sides in response to a variation in differential pressure between the lower and upper surfaces. Second, the material must be sufficiently airtight to allow the efficient transmission of overpressure to the volume 7 between the first and second sails 3, 4, thus ensuring the desired aerodynamic operation of the device 1.

[0109] The leading edge of the dynamic scoop 10 is positioned outside the volume 7 to form the inlet of said scoop 10. This leading edge is advantageously tensioned between a tack point A and a clew point E, which facilitates handling of the dynamic scoop 10. From this leading edge, the fabric forming the scoop 10 extends between the first and second sails 3, 4. The upper end of the scoop 10, or trailing edge, is held in a fixed position along the longitudinal axis Z'-Z and is free to move between the first and second sails 3, 4. The trailing edge of the dynamic scoop 10 can be secured along the longitudinal axis Z'-Z by a line attached to a halyard point D.Since the trailing edge of the dynamic scoop 10 is free in translation between the first and second sails 3, 4, the fabric forming the dynamic scoop 10 naturally presses against the extrados, under the action of the pressure difference between the intrados and the extrados.

[0110] The shape defined between the leading edge of the dynamic scoop 10 and the upper surface sail is designed to optimize the capture of dynamic pressure according to the specific operating conditions anticipated for said sail. Similarly, the length of the line securing the trailing edge of the dynamic scoop 10 along the longitudinal axis Z'-Z is adjustable. Finally, the tension of the leading edge of the dynamic scoop 10 is also adjustable.

[0111] Ship

[0112] One object of the invention is a vessel 2 comprising:

[0113] - a mast 20 with a halyard point D;

[0114] - a tack point A and a listening point E;

[0115] - a device 1 according to the invention, the first and second fixing zones of the tubular envelope 5 being respectively fixed to the tack point A and the halyard point D, the first and second sails 3, 4 being fixed to the clew point E.

[0116] According to one embodiment, the position of the tack point A can be modified so as to adjust the orientation of the longitudinal axis Z'-Z of the tubular envelope 5. Thus, it is possible to modify the value of the torques exerted by the first and second walls 2, 3 on the tubular envelope 5.

[0117] The invention is not limited to the embodiments described. A person skilled in the art is able to consider their technically operative combinations and to substitute equivalents for them.

Claims

DEMANDS 1. Sail propulsion device (1) for equipping a vessel (2) having a halyard point (D), a tack point (A) and a sheet point (E), the device (1) comprising: - the first and second sails (3, 4), opposite, and connected to each other in such a way as to share a trailing edge (BF) intended to be fixed to the clew (E); - a tubular envelope (5), inflatable, extending along a longitudinal axis (Z'-Z), and comprising: first and second attachment zones opposite each other along the longitudinal axis (Z'-Z), intended to be attached respectively to the tack point (A) and the halyard point (D); a leading edge (BA), intended to face a wind (V), and defining with the trailing edge (BF) a camber line (Ll) which changes according to a wind direction (V); a joining zone (6), on which the first and second sails (3, 4) are joined, having an angular position (Q) defined with respect to the leading edge (BA) and the longitudinal axis (Z'-Z) which varies according to the camber line (Ll);device (1) in which the tubular envelope (5) delimits a closed chamber filled with a fluid (F), preferably air, exerting a pressure inside the tubular envelope (5), the pressure being different from atmospheric pressure and determined as a function of a wind speed (V) so that the leading edge (BA) is kept under tension.; 2. Device (1) according to claim 1, comprising a control circuit configured to regulate the pressure exerted by the fluid (F) inside the tubular envelope (5) as a function of the wind speed (V).

3. Device (1) according to claim 1 or 2, in which the first and second sails (3, 4) are connected to each other so as to delimit a volume (7) open at their base with the tubular envelope (5), the open volume (7) allowing an inlet of air at atmospheric pressure.

4. Device (1) according to claim 1 or 2, wherein: - the first and second sails (3, 4) are connected to each other in such a way as to delimit a closed enclosure with the tubular envelope (5); - the closed enclosure is filled with a fluid, preferably air, exerting a controlled pressure inside the closed enclosure so as to modulate a volume (7) of the closed enclosure.

5. Device (1) according to claim 4 in combination with claim 2, wherein the control circuit is configured to regulate the pressure exerted by the fluid inside the closed enclosure.

6. Device (1) according to claim 1 or 2, wherein: - the first and second sails (3, 4) are connected to each other in such a way as to delimit a volume (7) with the tubular envelope (5); - a dynamic scoop (10) is arranged to capture an airflow at atmospheric pressure and to redirect said airflow so as to modulate the volume (7).

7. Device (1) according to any one of claims 1 to 6, wherein the tubular envelope (5) is free to rotate about the longitudinal axis (Z'-Z).

8. Device (1) according to any one of claims 1 to 7, comprising drive means arranged to drive the tubular envelope (5) in rotation around an axis of rotation passing through the first and second fixing zones.

9. Device (1) according to claim 8, in which the axis of rotation passing through the first and second fixing zones and the longitudinal axis (Z'-Z) are coincident, or parallel, or intersecting.

10. Device (1) according to any one of claims 1 to 9, comprising adjustment means arranged to adjust the angular position (Q) of the junction zone (6).

11. Device (1) according to any one of claims 1 to 10, comprising a zipper (8a, 8b) arranged to connect the first and second sails (3, 4) together on the junction area (6) or to connect the first and second sails (3, 4) together along the trailing edge (BF).

12. Device (1) according to any one of claims 1 to 11, comprising a yard (9) having first and second ends (90, 91) opposite, the first end (90) being connected to the trailing edge (BF), the second end (91) being connected to the second fixing zone of the tubular envelope (5).

13. Vessel (2) comprising: - a mast (20) having a halyard point (D); - a tack point (A) and a listening point (E); - a device (1) according to any one of claims 1 to 12, the first and second fixing zones of the tubular envelope (5) being respectively fixed to the tack point (A) and the halyard point (D), the first and second sails (3, 4) being fixed to the clew point (E).

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