Wind propulsion unit and ship equipped with such a unit

Abstract

The present invention relates to a wind propulsion unit with a double sail attached to a structure that is angularly controlled around a generally vertical axis depending on the circumstances, the double sail comprising a forward flap (100), an aft flap (200) and a support structure (300) that allows the forward and aft flaps to pivot around two generally parallel and spaced apart axes, the unit also comprising a device for controlling the orientation of the aft flap according to the wind incidence direction during propulsion. According to the invention, the device for controlling the orientation of the aft flap is also configured to bring the aft flap (200) into a folded orientation in which a substantial part of its cross-sectional area is arranged along a substantial part of the cross-sectional area of ​​the forward flap (100) when the wind propulsion unit is in the non-operating position.

Description

[Technical field]

[0001] The present invention relates generally to wind propulsion, and more particularly to a new type of propulsion sail for cruisers and workboats. [Background technology]

[0002] In particular, PCT Publication Nos. WO 2018087649(A1) and WO 2020115717(A1) describe a wind propulsion device with a double sail attached to a structure that is angle-controlled around a generally vertical axis depending on the circumstances, the double sail comprising a forward flap and an aft flap and a forward mast and an aft mast connected by an element forming a boom and an element forming a gaff, the forward flap being traversed by the forward mast and rotating around an axis defined by the forward mast, and the aft flap being traversed by the aft mast and rotating around an axis defined by the aft mast. The structure can rotate on a rotation axis arranged on the forward mast.

[0003] US Patent Application Publication No. 2018162502(A1) also describes a submersible with dual sails that can be tilted to limit drag during diving movements. The sails also incorporate a complex mechanism for laterally moving and positioning the rear flaps along with the front flaps.

[0004] Finally, GB 2590082(A) describes a three-flap sail in which the rear flap can be oriented opposite to the orientation of the other two flaps, however in this position the sail still has a significant footprint. Summary of the Invention

[0005] The object of the invention is to provide a particularly simple and effective solution for selectively limiting the size of a device comprising two flaps with variable orientation when not in use.

[0006] For this purpose, a double sail propulsion unit has been proposed, which comprises double sails attached to a structure whose angle is controlled around a generally vertical axis depending on the situation, the double sail comprising a forward flap, an aft flap and a support structure enabling the forward and aft flaps to pivot around two generally parallel and spaced apart axes, and also comprising a device for controlling the orientation of the aft flap according to the wind incidence direction during propulsion, but the device for controlling the orientation of the aft flap is also configured so that, when the sail propulsion unit is in a non-operating position, the aft flap is in a folded orientation in which the majority of its cross-sectional area is arranged along the majority of the cross-sectional area of ​​the forward flap.

[0007] The wind propulsion unit may optionally comprise the following additional features, either individually or in any combination that a person skilled in the art would understand to be technically compatible with one another: * The forward flaps have no directional control device and are free to move within a range of angles in use, and the aft flaps can bias and angularly shift the forward flaps as they approach their folded position to minimize the footprint of the flaps in the direction of their thickness. * The angular offset of the forward flaps is such that the axes of their cross-sectional profiles are generally parallel in the folded position. * The axis of the flap profile in cross section is angularly offset from a plane containing the axes of both masts in the folded position by approximately 2-20°. * In the folded position, the trailing edge of the aft flap is near the leading edge of the forward flap. * The support structure comprises at least one boom element and / or gaff element, and in the folded position and cross section, the forward and aft flaps are fully inscribed within the contour of the boom element and / or gaff element. *The unit also includes means for locking the rear flap in its folded position.

[0008] A watercraft is also proposed, characterized in that it comprises at least one wind propulsion unit as described above.

[0009] In a particular embodiment the marine vessel comprises a mechanism for moving the or each wind propulsion unit from an operative position to a non-operative position, the folding controller being controlled in conjunction with control of that mechanism.

[0010] The inoperative position may in particular be a stowed or stored position. [Brief description of the drawings]

[0011] Other aspects, objects and advantages of the present invention will become more apparent from reading the following detailed description of preferred embodiments thereof, given as non-limiting examples and made with reference to the accompanying drawings, in which: [Figure 1] 1 is a general perspective view of a wind propulsion system according to an embodiment of the present invention in an operating position; FIG. [Diagram 2] FIG. 2 is a schematic horizontal cross-sectional view of the device shown in FIG. 1 at the same position as in FIG. [Diagram 3] FIG. 3 is a general perspective view of the device shown in FIGS. 1 and 2 in a non-operating position; [Figure 4] FIG. 4 is a schematic horizontal cross-sectional view of the device shown in FIGS. 1 to 3, taken at the same position as FIG. 3. [Diagram 5] FIG. 1 is a perspective view of a particular embodiment of a wind propulsion system according to the invention; [Figure 6] FIG. 6 is a perspective view showing the device of FIG. 5 in a lowered position. [Figure 7] FIG. 7 is a perspective view of the device of FIG. 6 in a folded state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] With reference to the drawings, the wind propulsion system according to the invention takes the form of a sail with two aerodynamic airfoils, both of which are adjustable in terms of incidence angle and relative pitch angle, which will be referred to below as the first or forward flap and the second or aft flap, which are respectively indicated with the reference numbers 100 and 200. They pivot on an axis defined by two respective masts 310, 320, which in this case are cylindrical, as will be seen below.

[0013] At least one of these airfoils has a longitudinally asymmetric aerodynamic cross section (having a leading edge and a trailing edge), which may be, for example, a symmetric sail section or, more preferably, a NACA 00xx standard cross section.

[0014] The relative angle of the second flap to the first flap is optionally adjustable differently depending on height to allow the second flap to twist.

[0015] Details of the operation and wind behavior of such a device can be found in PCT Publication No. WO2020115717(A1).

[0016] The device further comprises a rigid frame 300, here formed by two cylindrical masts 310, 320 of constant outside diameter, and by lower and upper, generally horizontal structural elements 330, 340, respectively, forming the boom and gaff elements. This structural frame is free to rotate about a vertical axis A1 formed by the forward mast 310. The elements of this structural frame are, for example, made of metal or composite parts suitably dimensioned for the stresses involved.

[0017] In this example, the aft mast 320 may have a smaller diameter than the diameter of the forward mast 310, since the thickness of the aft flap 200 is less than the thickness of the forward flap 100. It shows the axis A2 about which the aft flap 200 pivots relative to the structure 300.

[0018] The structure 300 as a whole is supported by a pivot 500 mounted on the deck of the ship so that it can be rotated relative to the ship using suitable controls, but the axis of rotation of the structure as a whole advantageously coincides with the axis A1 defined by the forward mast 310.

[0019] The means for controlling the orientation of the forward and aft flaps about the mast may be of the type described in PCT International Publication No. 2020115717(A1), although other means are of course also possible.

[0020] According to one aspect of the present invention, the device may be in an operating position as shown in Figures 1 and 2, however it should be noted that the degrees of freedom of the flaps are in rotation, and, where applicable, in torsion, as described in PCT International Publication No. WO2020115717(A1), and that the positions shown in Figures 1 and 2 are positions in which the two flaps are in a central position.

[0021] When the space or footprint is reduced, the device is designed to allow the rear flap 200 to be folded forward about its pivot axis A2 through an angle of about 180° so that it lies alongside the forward flap.

[0022] This arrangement reduces the front and rear footprint of the device, e.g. -Limiting exposure to wind in case of storms; - facilitating the stowage of the vessel when it is necessary to store it by tilting the vessel, by translating it along one of the vessel's main axes (longitudinal, transverse and vertical), or by any combination of movements; - for example, during loading and unloading operations when the equipment is on board a commercial vessel; - or limiting the shape factor of the device during the manufacturing, shipping or handling stages.

[0023] The folding movement of the rear flap is advantageously accompanied by a slight angular displacement of the forward flap 100 by rotation about its axis A1, as shown in Fig. 4 by its longitudinal axis AA, relative to the plane of the support structure 300, by an angle α1, as can be seen clearly in Fig. 4. This allows the rear flap 200 to be folded without the trailing edge 110 of the forward flap impeding this movement. Advantageously, the angular offset of the forward flap is such that the axes AV1, AV2 of the forward and rear flap contours in cross section are generally parallel.

[0024] In the first case, the front flap is passive, i.e. it does not have a specific actuator and in operation it moves freely within a certain angular range when the wind is blowing. In this case, the rear flap slightly stresses the front flap when it folds, shifting it angularly and thus bringing the axes AV1 and AV2 of the two flap profiles into a parallel or slightly inclined relationship. In this case, the gap between the two flaps shown in FIG. 4 does not exist. The load can be applied, for example, directly to the entire flap surface, or to internal flap form elements, or to dedicated local support elements.

[0025] In the second case, the forward flap is provided with an orientation change device which is operated to move the axis AV1 of the forward flap profile into a position parallel or slightly inclined with respect to the axis AV2 of the aft flap profile.

[0026] Similarly, advantageously, at the end of folding, the cross-sections of the forward and aft flaps are completely inscribed in the profile of the boom element, and preferably also inscribed in the profile of the gaff element.

[0027] More precisely, for a conventional sail profile, in this position, the angle α1 formed by the axis AV1 of the forward flap relative to the longitudinal axis AA of the structure 300 is advantageously between 2 and 20°, while the angle α2 formed by the axis AV2 of the aft flap relative to said longitudinal axis AA is advantageously between 160 and 178°, these values ​​essentially depending on the type of respective profile of the flaps (in particular the length / thickness ratio).

[0028] The rear flap is folded either manually or by a motor (if the front flap is not free, the front flap is angled). In case of motor control, the end-of-stroke control arrangement can be provided based on any type of servo drive, in particular mechanical, optical, electrical or electromagnetic servo drives, or with a stepper motor for fine adjustment of the angular position at the end of folding. In particular, the orientation control mechanisms described in PCT Publication WO2020115717A1 can be used, but the skilled person will be able to make the necessary adaptations.

[0029] It is also possible to mechanically lock the two flaps in the folded position relative to each other or to the frame 300. The locking means may for example comprise locking fingers provided on or in the boom element 330 or the gaff element 340 and cooperating with associated arrangements mechanically actuated, for example by means of an electromagnet.

[0030] 5-7, a windbreak device that can lower forward flaps and flaps, as described, for example, in PCT International Publication No. WO 2020115717(A1), is shown.

[0031] The two flaps are here defined respectively by a series of forward shaping elements 120 and a series (preferably the same number) of aft shaping elements 220, which together describe envelopes of symmetric aerodynamic contours intended to cooperate with the respective envelopes 110, 210 to form the first flap 100 and the second flap 200.

[0032] These form elements are free to rotate and translate on their respective masts 310, 320, allowing the two flaps to be raised and lowered, and reefed if necessary.

[0033] In FIG. 5, the propulsion system is in its operational state and the tilt of the forward and aft flaps is controlled according to the navigation conditions.

[0034] In FIG. 6, both flaps are lowered to occupy limited space along the boom element 330.

[0035] Finally, in FIG. 7, the rear flap is folded over against the front flap as described above.

[0036] In particular, this lowers the centre of gravity of the device when underway.

[0037] It will be appreciated that the present invention is in no way limited to the embodiments described above and shown in the drawings, rather those skilled in the art will know how to make numerous variations or modifications.

Claims

1. 1. A double sail propulsion unit comprising a double sail mounted on a structure whose angle is controlled around a generally vertical axis depending on the situation, the double sail comprising a forward flap (100), an aft flap (200) and a support structure (300) enabling the forward and aft flaps to pivot around two generally parallel and spaced apart axes, the unit also comprising a device for controlling the orientation of the aft flap according to the wind incidence direction during propulsion, the device for controlling the orientation of the aft flap also being configured to place the aft flap (200) in a folded orientation in which a substantial portion of its cross-sectional area is disposed along a substantial portion of the cross-sectional area of ​​the forward flap (100) when the sail propulsion unit is in an inoperative position.

2. 2. The unit of claim 1, wherein the front flaps have no directional control device and are free to move within an angular range in use, and the rear flaps can bias the front flaps (100) to shift angularly as the front flaps approach their folded position to minimize the footprint of the flaps in their thickness direction.

3. 2. A unit according to claim 1, characterized in that it comprises a device for controlling the orientation of the rear flap, which in the folded position of the rear flap (200) makes it possible to angularly shift the front flap (100), thereby minimizing the footprint of the flaps in the direction of their thickness.

4. 4. A unit according to claim 2 or 3, characterized in that the angular offset of the front flaps is such that their cross-sectional profile axes (AV1, AV2) are generally parallel in the folded position.

5. A unit according to claim 3 or 4, characterized in that the axis of the profile of the cross section of the flap (100, 200) is, in the folded position, angularly offset by about 2 to 20° from a plane containing the axes of both masts.

6. A unit according to any one of the preceding claims, characterized in that in the folded position, the rear edge of the rear flap is located adjacent to the front edge of the front flap.

7. A unit as claimed in any one of claims 1 to 6, characterised in that the support structure comprises at least one boom element and / or gaff element, and in the folded position and in the cross section, the front flap and the rear flap are completely inscribed in the contour of the boom element and / or the gaff element.

8. A unit according to any one of the preceding claims, further comprising means for locking the rear flap in its folded position.

9. An at least partly wind-propelled watercraft, characterised in that it comprises at least one wind propulsion unit according to any one of the preceding claims.

10. 10. A watercraft as claimed in claim 9, characterized in that it comprises a mechanism for moving the or each wind propulsion unit from an operative position to an inoperative position, the folding control device being controlled in conjunction with the control of said mechanism.

11. 11. The watercraft of claim 10, wherein the inoperative position is a stowed or stored position.

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