EP4308450A1

EP4308450A1 - Tethered-wing traction system including folding into a windsock

Info

Publication number: EP4308450A1
Application number: EP22716061.1A
Authority: EP
Inventors: Benoit Gagnaire; Jèrome RIGAUD
Original assignee: Airseas SAS
Current assignee: Airseas SAS
Priority date: 2021-03-19
Filing date: 2022-03-17
Publication date: 2024-01-24
Also published as: CN116940505A; US20240166320A1; FR3120845A1; CA3211321A1; FR3120845B1; WO2022195046A1; KR20230157408A; JP2024510154A

Abstract

A method for deploying a tethered-wing traction system, comprising a step of flying a traction wing (5) relative to a mooring mast (4), and, prior to the flying step, a step of folding the traction wing (5) into a windsock, in which: the middle zone (15) of the leading edge (16) is maintained with respect to the mooring mast (4) at a first height on the mooring mast (4); the lateral portions (19) of the leading edge (16) are maintained with respect to the mooring mast (4) at least at a second height on the mooring mast (4), below the first height; and the trailing edge (17) is closed by the moving together of the lateral portions of the trailing edge (17).

Description

DESCRIPTION

CAPTIVE AILING TRACTION SYSTEM WITH AIR SLEEVE FOLDING

TECHNICAL AREA

The invention relates to the field of captive wing traction systems which are adapted to deploy and fold a traction wing relative to a base platform, this traction wing being adapted to generate a traction force under the effect of the wind .

Such traction systems allow the deployment of a flying traction wing used for the propulsion of a vehicle, in particular a ship (as a main mode of propulsion, or as assistance), for the production of electricity , or for any application that takes advantage of such a pulling force.

PRIOR ART

French patent application FR3082184 describes a tethered wing traction system and a method of deploying and folding the traction wing. The towing wing has fold lines attached to its leading edge, and the system includes means for pulling at least three fold lines to bring the leading edge back against the mast at at least two different heights along the along this mast.

This traction system benefits from a more efficient and safer deployment and retraction process.

DISCLOSURE OF THE INVENTION

The aim of the invention is to improve the tethered wing traction systems of the prior art, as well as the associated deployment methods.

To this end, the invention relates to a method for deploying a tethered wing traction system, comprising a traction wing adapted to generate a traction force under the effect of the wind, and adapted to be deployed and folded in relation to a base platform which is provided with a stowage mast, the traction wing having: a trailing edge which comprises two lateral portions; and a leading edge which comprises a middle zone and two lateral portions; this process comprising a step of taking off the traction wing relative to the stowage mast, as well as a step of folding the traction wing into a windsock, before the take-off step.

In this windsock folding step of the traction wing:

- the middle zone of the leading edge is maintained with respect to the stowage mast at a first height on the stowage mast; - the lateral portions of the leading edge are held relative to the stowage mast at least at a second height on the stowage mast, lower than said first height;

- the trailing edge is closed by mutual approximation of the side portions of the trailing edge.

According to another object, the invention relates to a captive wing traction system, comprising:

- a traction wing adapted to generate a traction force under the effect of the wind, and adapted to be deployed and folded with respect to a base platform which is provided with a lashing mast, the traction wing having : a trailing edge which has two side portions; and a leading edge which comprises a middle zone and two lateral portions;

- several fold lines each having one end fixed to the leading edge, being spaced apart from each other along this leading edge.

This traction system also includes:

- a line connected to the middle zone of the leading edge;

- at least one closing line connected to the trailing edge;

- a control unit adapted to control traction on the line which is connected to the middle zone, the folding lines, and the closing line, this control unit comprising a windsock folding mode in which: the zone median of the leading edge is maintained relative to the stowage mast at a first height on the stowage mast, by pulling the line which is connected to the middle zone; the lateral portions of the leading edge are held relative to the stowage mast at at least a second height on the stowage mast, lower than said first height, by pulling the folding lines; the trailing edge is closed by a mutual approach of the lateral portions of the trailing edge, under the effect of a traction of the closing line.

Such a traction system and such a deployment method make it possible to go through an intermediate phase of windsock folding of the traction wing.

This windsock folding step designates here precisely a conformation of the traction wing, specific to the invention, in which the leading edge forms an air inlet, while the trailing edge is sufficiently closed to that the traction wing thus folded into a windsock behaves like a pocket which can be filled with air.

In this windsock folding configuration, the traction wing is similar to a windsock with a circular opening and a converging tube effect which tends to stabilize the wing.

This geometrical conformation, which can advantageously be controlled dynamically by acting jointly on the guide line, on the fold lines and the closing lines, stabilizes the traction kite and avoids any fluttering just before the lift of the traction kite.

This folding stage in windsock also allows to inflate the traction wing and to give it power, just before its flight so that the latter takes place without phase of uncertainty where the traction wing could lose its trajectory or lift.

The deployment method according to the invention may comprise the following additional characteristics, alone or in combination:

- the middle zone of the leading edge is held in relation to the lashing mast by pulling a line which is connected to the middle zone of the leading edge;

- the lateral portions of the leading edge are held in relation to the stowage mast by pulling fold lines which each have one end fixed to the leading edge while being spaced apart from each other along this edge of attack;

- the fold lines are arranged in symmetrical pairs, each fold line of a pair connecting the middle zone of the leading edge to another zone of the leading edge, and the traction of the fold lines is achieved by pulling together on both lines of each pair of folding lines;

- the lateral portions of the leading edge are held in relation to the lashing mast by pulling at least three pairs of symmetrical folding lines, following at least three heights along the lashing mast;

- the trailing edge is closed by pulling at least one closing line connected to the trailing edge;

- during the windsock folding step, the closing line is gripped by a first carriage sliding along the lashing mast;

- during the windsock bending step, the bending lines are each gripped in a sliding manner by a carriage located under the first carriage;

- said line which is connected to the middle zone of the leading edge, is connected to the middle zone by a clamping means, and is connected to the closing line, the windsock folding step comprising an operation of releasing or pulling the closure line, this operation comprising the following tasks: opening the clamping means; loosening or pulling of said which is connected to the middle zone of the leading edge, resulting in loosening or pulling on the line of closure; closure of the clamping means. The traction system according to the invention may comprise the following additional characteristics, alone or in combination:

- the system comprises carriages sliding along the lashing mast adapted to slidably grasp the line which is connected to the middle zone and the folding lines, these carriages being spaced from each other along the lashing mast when the control unit is in windsock folding mode;

- the line which is connected to the middle zone is connected to the middle zone by a clamping means, and is connected to the closing line, the control unit being adapted to control the clamping means so that, when it is in its windsock folding mode, the control unit is successively adapted to: open the clamping means; release or pull the line that is connected to the middle zone, causing a release or pull on the closing line; close the clamping means.

- the closing line runs along the trailing edge passing through rings;

- the closing line connects the two lateral portions of the trailing edge;

- the closing line forms a loop between two rings each arranged on a lateral portion of the trailing edge.

PRESENTATION OF FIGURES

Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which:

- [Fig.1] shows in perspective a ship propelled by a captive wing traction system according to the invention;

- The [Fig.2] schematically illustrates the elements of Figure 1, seen in profile;

- [Fig.3] represents the traction wing of the system of Figure 1, front view;

- [Fig.4] illustrates a fallback step of the system of Figure 1;

- [Fig.5] illustrates another folding step of the system of Figure 1;

- [Fig.6] illustrates the traction wing in the folded position along the lashing mast;

- [Fig.7] illustrates a step for storing the traction wing; - [Fig.8] illustrates another step for storing the traction wing;

- [Fig.9] illustrates a deployment stage of the traction wing;

- [Fig.10] illustrates another stage in the deployment of the traction wing;

- [Fig.11] illustrates a windsock folding step of the traction wing;

- [Fig.12] shows in perspective the traction wing of figure 11;

- [Fig.13] shows the traction wing of figure 11, front view;

- [Fig.14] illustrates another stage in the deployment of the traction wing;

- [Fig.15] shows in perspective the traction wing of figure 14;

- [Fig.16] illustrates an alternative embodiment of the traction system;

- [Fig.17] illustrates another alternative embodiment of the traction system;

- [Fig.18] illustrates an embodiment for routing the closing line on the trailing edge of the traction wing;

- [Fig.19] illustrates another embodiment for routing the closing line on the trailing edge of the traction wing.

Similar elements common to the various embodiments bear the same reference numbers in the figures.

DETAILED DESCRIPTION

Figure 1 illustrates a captive wing traction system 1, mounted on a ship 2 which is, in this example, a sea freight ship (in Figure 1, only the front of the ship has been shown).

In the present example, the traction system 1 is mounted at the bow of the ship 2 and is operated as a complementary means of propulsion of the ship allowing fuel savings. In this context, the traction system 1 is sized according to the tonnage of the ship to be towed and is designed to be deployed and folded automatically.

As a variant, this traction system 1 can be used for any other application where such an automatically deployable and folding traction system is desired, for example as the main means of propulsion of a ship, for the propulsion of any other vehicle, for the power generation, etc. The traction system 1 comprises a base platform 3 which is fixed here to the deck of the ship 2 and on which is mounted a stowage mast 4 provided for the automatic deployment and folding operations of the system.

The traction system 1 further comprises a traction wing 5 which is adapted to generate a traction force under the effect of the wind. In the present example, the traction wing 5 is a paraglider type wing. Any other flying equipment suitable for generating a pulling force under the effect of the wind can alternatively be used, such as kites, gliding equipment, “kite” type sails, etc. The traction wing 5 comprises, in a conventional manner, a leading edge 16 intended to be exposed to the incident wind and an opposite edge, called the trailing edge 17.

The traction wing 5 is connected by a set of lines of suspension 6 to a flight path control device 7 which is adapted to act on the lines of suspension 6 to control the flight of the traction wing 5.

The traction system 1 further comprises a traction line 8 connecting the steering wheel trajectory control device 7 to the base platform 3. The traction force generated by the traction wing 5 is transmitted by the traction line 8 to the vessel 2 for its propulsion, and the traction line is sized accordingly. In the context of the traction of a sea freight ship, the traction line can be, for example, a textile cable whose diameter can reach several centimeters.

The flight path control device 7 makes it possible to control the flight of the traction wing 5 in order to orient and position the traction wing and possibly to train the traction wing 5 to describe flight figures allowing to increase the tractive force on the vessel. The control of the trajectory of the traction wing 5 is obtained here by controlling the length of certain mobile lines of suspension, in a conventional manner in the field of flying wings. All of the hanger lines 6 indeed comprise fixed hanger lines (that is to say which has a fixed length between their attachment to the traction wing 5 and their attachment to the trajectory control steering wheel device 7 ), and mobile lines of suspension whose length is variable. The flight path control device 7 is thus adapted to pull on certain mobile lines of suspension and/or to release other mobile lines of suspension, so that the aerodynamic profile of the traction wing 5 is modified with a view to control its lift, trajectory, etc. The modification of the profile of a traction wing for the control of its trajectory is carried out in a conventional manner and will not be described in more detail here. The traction wing 5 further comprises a guide line 9 and several folding lines 10A, 10B, 10C which are all integral with the leading edge 16 ^, by at least one of their ends.

Figure 2 is a profile view of the traction system 1 in the vessel's traction phase, as in Figure 1. Figure 2 also schematically illustrates the constituent elements of the traction system 1.

The traction line 8 is connected to the base platform 3 by means of a winch 11 controlled by a motor, for example electric or hydraulic, adapted to unwind the traction line 8 to allow the traction wing 5 to gain altitude, or on the contrary to roll up this traction line 8 to bring the traction wing 5 back to the base platform

3.

Figures 1 and 2 illustrate the traction system 1 in a traction configuration, the traction wing 5 being deployed and in flight, and the system participating in the propulsion of the ship.

The traction system 1 further comprises carriages 12A, 12B, 12C, 12D, which are four in number in this example. These trolleys are slidably attached to the lashing mast 4 and are each motorized so that the position of each trolley along the lashing mast 4 can be piloted. These trolleys are designed to grip and guide the guide line 9, possibly via a securing line, or even an intermediate piece, and the folding lines 10A, 10B, 10C during the deployment or fallback described below.

The traction wing 5 further comprises closure lines 13 which make it possible to close the trailing edge 17. These closure lines 13 extend transversely to the traction wing 5 and one of their ends is fixed to the trailing edge 17 while the other end is disposed near the leading edge 16. The closure lines 13, which are shown in dotted lines in Figure 2, preferably run on the underside of the traction wing 5 , and can alternatively walk on the top, or through the inside of the traction wing 5.

Lock lines 13 can be grasped or maneuvered from an area near leading edge 16 such that a pull on these lock lines 13 results in a pull on one or more portions of trailing edge 17.

In the present example, the various closing lines 13 are grouped into one or more main lines which project from the leading edge 16. The closing lines 13 are preferably entered by a suitable device of the lashing mast 4. Each trolley 12A, 12B, 12C, 12D has means of attachment, automatic or manual, allowing certain lines to be entered selectively.

The traction system 1 further comprises a control unit 30 consisting of conventional electronic means for controlling and enslaving the various actuators of the system. The control unit 30 controls here in particular the position and the movement of the motorized carriages 12A, 12B, 12C, 12D, the action of the winch 11, and any other actuator participating in the operation of the system, as well as a possible hydraulic unit and the associated actuators.

Figure 3 illustrates the traction wing 5 alone, in its position of Figures 1 and 2, front view. This figure 3 shows in particular: all of the lines of lines 6 connecting the traction wing 5 to the flight path control device 7; guide line 9, and fold lines 10A, 10B, 10C.

In the present example, the fold lines are distributed in three pairs of fold lines symmetrically connecting a middle portion 15 of the leading edge 16 to other points regularly distributed on the leading edge 16. The edge of attack 16 in fact comprises: - a middle zone 15 which is located substantially in the middle of the leading edge 16, that is to say substantially at equal distance, on this leading edge 16, between the two lateral ends 18 of traction wing 5;

- two lateral portions each located between the middle zone 15 and one of the lateral ends 18.

The fold lines 10A, 10B, 10C are thus fixed to the leading edge 16 while being spaced apart from each other along this leading edge.

The guide line 9 for its part connects the middle zone 15 to the flight path control device 7. Optionally, the guide line 9 is connected to the traction wing 5 by an intermediate piece.

The closure lines 13 are also accessible from the middle zone 15 of the leading edge 16, either directly or by being connected to the guide line 9 (see examples given with reference to FIGS. 16 and 17).

Thus, all of the lines 9, 10A, 10B, 10C, and 13 are accessible or operable from the middle zone 15 of the leading edge 16.

The traction system 1 is adapted to be folded and deployed automatically. The method of folding the traction system 1 from its traction position of Figures 1 and 2 will now be described with reference to Figures 4 to 8. From the positions of Figures 1 and 2 in which the traction wing 5 is in flight phase, the folding process is initiated by actuating the winch 11 to bring the traction wing 5 back to the base platform 3, as illustrated in FIG. 4. This step immobilizes the flight path control device 7 on the base platform 3, for example on a suitable support (not shown), while the traction wing 5 remains inflated by the wind. This step therefore preferably takes place by orienting the stowage mast 4, and therefore the traction wing 5, facing the wind, so that the direction of the wind is perpendicular to the leading edge 16.

From this position of Figure 4, several lines are entered by the carriages 12A, 12B, 12C, 12D. Each trolley includes, for example, attachment means, such as hooks or carabiners, making it possible to grip a line in a sliding manner. The positioning of these attachment means on the lines is preferably done automatically, by an actuator controlled by the control unit 30, but can also be done manually. The translation of the carriages 12A, 12B, 12C, 12D can also be used to actuate the seized lines by exerting a traction on certain lines thanks to a movement of separation between two carriages.

In the present example, the input of rows by the carriages is carried out as follows:

- The guide line 9 is entered by the first carriage 12A, directly or indirectly;

- the first pair of folding lines 10A is entered by the second carriage 12B, that is to say that the carriage 12B slidably encloses the two lines 10A together;

- The second pair of fold lines 10B is entered by the third carriage 12C;

- The third pair of fold lines 10C is entered by the fourth carriage 12D.

According to a variant illustrated in FIG. 4, the trolley 12A grasps the guide line 9 via a securing line 20, coming from a winch 21 also controlled by the control unit 30, and which passes through a pulley or a ring of the carriage 12A, and whose end is slidably hooked on the guide line 9.

The attachment of the lashing line 20 to the guide line 9, and the traction exerted by the winch 21, make it possible to immobilize the traction wing 5 by maintaining the middle zone 15 of its leading edge 16 against the trolley 12A and therefore against the lashing mast 4.

Similarly, the other carriages 12B, 12C, 12D each enter their pair of fold lines 10A, 10B, 10C at the level of the middle zone 15, where the fold lines of each symmetrical pair meet.

From the position of Figure 4, and after the lines 9, 10A, 10B, 10C have been entered, the carriages 12B, 12C, 12D which surround the folding lines then descend along mast 4. During the descent carriages 12B, 12C, 12D, the latter slide along the fold lines by stretching each of the lines vertically from the middle zone 15, and therefore bringing the side portions 19 towards the mast 4, until the traction wing 5 is folded in two. Figure 5 illustrates an intermediate stage of this descent of the carriages, up to the folding position which is shown in perspective in Figure 6. In this position, the side portions 19 of the leading edge 16 are opposite each other. live with each other. In this folding position of FIG. 6, the traction wing 5 can be furled by any means making it possible to compress it in the direction 23 and/or in the direction 24. This furling can be achieved by traction on lines of dedicated furling, or alternatively on the closing lines 13. This pulling on the closing lines 13 can be achieved for example by pulling the guide line 9 (which can be connected to the closing lines 13) and/or by trolleys furling not shown.

The traction kite 5 furled in this way is ready to be stowed.

The schematic figures 5 and following simply illustrate the main elements showing the cooperation of the carriages and the traction wing 5, the other elements such as the trajectory control device 7 or the lines 6 not having been represented to lighten the difficulties. figures.

From this position of Figures 6 and 7, and with reference to Figures 7 and 8, the four carriages 12A, 12B, 12C, 12D then slide down along the lashing mast 4 to store the traction wing 5 in a housing 22. This descent of the carriages is done by maintaining a mutual spacing between them, which allows the maintenance of traction on the folding lines 10A, 10B, 10C. The traction wing 5 is thus lowered along the mast until it is stored in housing 22.

Figure 8 illustrates the traction system 1 in the folded position, the traction wing 5 being entirely arranged inside the housing 22.

From this fallback position of Figure 8, the deployment method of the traction system 1 will now be described. The steps of the deployment method are initiated at the folded position in FIG. 8 and take place in the opposite direction to the folding steps described above.

The carriages 12A, 12B, 12C, 12D are first of all reassembled by sliding along the lashing mast 4 passing through a position corresponding to that of FIG. 7, up to the folding position of FIG. 6 in which the traction wing 5 is kept folded along the tie-down mast 4, with the middle zone 15 of the leading edge 16 held against the tie-down mast 4.

This folding position of FIG. 6 is also shown in profile view in FIG. 9. In this position, the traction wing 5 is still furled by maintaining traction on furling lines and/or on the closing lines 13. The traction wing 5 then passes to a windsock folding step. The furling of the traction wing 5 is released then a certain tension is exerted on the closing lines 13. FIG. 10 schematically illustrates (with a maximum rear edge shown in dotted lines) this phase where the furling of the traction wing 5 is released while the trailing edge 17 is closed by the action of the closure lines 13.

The carriages 12B, 12C, 12D are then raised along the lashing mast 4 to the windsock folding position illustrated in Figures 11 to 13. In this windsock folding position:

- the folding lines 10A, 10B, 10C are partially released, and the traction wing 5 is therefore partially open;

- the closure lines 13 are partially relaxed.

This windsock folding step is illustrated in profile in Figure 11, in perspective in Figure 12, and from the front in Figure 13.

As with the leading edge 16, the trailing edge 17 has two side portions 25 which face each other when the traction wing 5 is in the folded position. During the windsock folding step, the trailing edge 17 is closed by mutual bringing together of the lateral portions 25 of the trailing edge 17. The notion of closing the trailing edge refers to the partial bringing together of the lateral portions 25 of so that the bottom of the receptacle created by the traction wing 5, thus folded into an air sock, is partially closed. The traction wing 5 thus forms a receptacle which inflates with air (the traction wing being facing the wind). The side portions 19 of the leading edge 16 form an opening for this receptacle.

The control unit 30 includes a windsock folding mode in which:

- the middle zone 15 of the leading edge 16 is maintained with respect to the stowage mast 4 at a first height on the stowage mast (that of the trolley 12A), by pulling the guide line 9;

- the lateral portions 19 of the leading edge 16 are held relative to the stowage mast 4 by pulling the folding lines 10A, 10B, 10C, according to three different heights on the stowage mast 4, corresponding to the heights of the carriages 12B, 12C, 12D, these heights being lower than said first height;

- the trailing edge 17 is closed by bringing the side portions 25 of the trailing edge together, by pulling the closure lines 13. The windsock folding of the traction wing 5 corresponds to a shaping of the latter allowing it a certain grip in the wind in a stable manner.

As shown in the front view of Figure 13, the partial traction on the closure lines 13 causes the side portions 25 to come closer together, so that only one interstitial opening 26 is present in the bottom of the receptacle formed by the traction wing 5 thus folded into an air sock.

The Traction Kite 5 benefits from stable inflation and support even in adverse conditions, such as decreasing wind. The windsock folding of the traction wing 5 makes it possible to play on the shape of the traction wing 5 and therefore its drag and its resulting lift, in order to promote the stabilization, the opening, and the unfolding of the traction wing 5. The traction wing 5 is thus placed in a position conducive to its deployment. Indeed, it is during the deployment of the traction wing 5 that the disturbances of the incident wind risk disturbing, or even preventing the deployment of the traction wing 5. This method of deploying the traction wing 5 can thus be automated without hazards to be feared during the deployment phase.

During the windsock folding phase, the lift of the inflated receptacle which is formed by the traction wing 5 in this position is preferably dynamically controlled by the control unit 30, acting both on the closing lines 13 as on the fold lines 10A, 10B, 10C. The middle zone 15 of the leading edge 16 is however maintained against the stowage mast 4 throughout the windsock folding phase. In such a case of dynamic piloting of the wing folded in windsock, the closing lines 13 are controlled (pulled or on the contrary released dynamically) so as to obtain an interstitial opening section 16 suitable for given wind conditions . For example, the lower the wind speed, the more the trailing edge 17 will be closed to give power to the traction wing and allow it to stabilize.

Similarly, the fold lines 10A, 10B, 10C can be dynamically controlled by the control unit 30 which controls the movement of the carriages 12B, 12C, 12D to open more or less the side portions 19 of the leading edge 16, depending on the conditions. The height of the carriages 12B, 12C, 12D can be adjusted to give the traction wing 5 the desired windsock shape with a more or less wide opening. The leading edge 16 forms an entry whose section can be modulated.

After this windsock folding phase, when the traction wing 5 is sufficiently stable and powerful, the traction system passes to a stage of opening the traction wing 5 illustrated in FIG. 14 in which the trolleys 12B, 12C, 12D are raised enough to completely release the fold lines 10A, 10B, 10C so that the traction wing 5 is completely open, although held by the middle zone 15 of the leading edge 16 against the stowage mast 4. Figure 15 illustrates in perspective this open position of the traction wing 5.

The traction wing 5 is then ready for take-off and it is already exerting a traction force, so the next stage of the deployment consists in operating the winch 11 to release the traction line 8, and releasing the guide line 9, which causes traction wing 5 to rise to its flight position. The deployment process is thus complete.

Furthermore, figures 16 and 17 are partial views of the traction wing 5 and relate to two illustrative variants for the production of the closure lines 13.

According to a first variant illustrated in Figure 16:

- one end of the guide line 9 is fixed (for example by sewing) on the trailing edge 17 of the traction wing 5;

- the various closing lines 13A run on the underside of the traction wing 5, from their attachment on the trailing edge, and join together in a single closing line 13B.

The single closing line 13B projects from the leading edge 16. In this example, this line 13B exits through a ring 27 which is attached to the traction wing.

The guide line 9 and the single closing line 13B can be entered independently of each other from trolleys on the lashing mast 4, and can be controlled independently of each other. During the windsock folding step, the guide line 9 is thus gripped and pulled against the stowage mast 4, while the single closure line 13B is pulled or released during the dynamic control of the folded wing in windsock, to finally be released completely during the opening step of the traction wing 5.

For this variant, as for all the embodiments, the guide line 9 can be connected directly to the leading edge 16, as illustrated in FIG. 16, or can be connected to an intermediate element, the latter being itself -even connected by a link to the leading edge (this link can be a textile link, a connecting plate such as a rib, or any other means of connecting an intermediate element to the leading edge of the traction wing ).

Figure 17 illustrates a second variant of the arrangement of the guide line 9 and the closing lines. The closing lines 13Ase join here at a single point to which the guide line 9 is attached. In other words, the guide line 9 extends into closing lines 13A. Before its extension into closure lines 13A, the guide line 9 crosses a tightening means 28 which is attached to the traction wing 5 by a flexible link 31 (or which is directly fixed to the fabric of the traction wing 5 ). The clamping means 28 here comprise jaws 29 that can be closed on the guide line 9 to fix the latter relative to the leading edge 16. The jaws 29 can conversely be released (for example by an electromechanical control controlled by the control unit 30) and thus allow free sliding of the guide line 9 in the clamping means 28, so that a traction on the guide line 9 causes a traction on the closure lines 13.

Before the windsock folding phase, the traction wing 5 is first held against the lashing mast 4 thanks to traction on the guide line 9 while the jaws 29 are closed. During the windsock bending phase, a release of the closure lines 13 can take place by opening the jaws 29 and releasing the guide line 9 until the desired release is obtained for the closure lines 13, the jaws 29 are then closed again to ensure the maintenance of the leading edge 16 against the stowage mast 4.

Figures 18 and 19 illustrate two embodiments of the arrangement of the closure lines 13 on the trailing edge 17 of the traction wing 5.

With reference to figure 18, the closing lines 13 can travel with respect to the trailing edge 17 thanks to rings 33 fixed to the traction wing. The rings 33 can be replaced alternately by pulleys, or any other element slidably retaining the closure lines 13. In this example, a single closure line passes in double in a central ring 33, and forms a screw loop opposite the trailing edge. Pulling on the two strands of the closure lines 13 causes the trailing edge 17 to close, allowing the windsock folding described above.

Figure 19 gives another example of a simplified arrangement of the closure lines 13. A single closure line 13 runs through three rings 33 arranged on the trailing edge 17. The end of the closure line 13 is secured to a fixed point 32 on the traction wing 5. Similarly, a traction on the closing line causes the windsock to fold.

The line of closure 13 thus connects the two lateral portions 25 of the trailing edge 17, by forming a loop between two rings 33 each arranged on one of these lateral portions 25. The line of closure 13 acts in the manner of a lasso, thanks to a loop which is adapted to reduce the perimeter of the trailing edge 17, making it circular, by an action similar to that of a diaphragm.

Alternative embodiments of the traction system 1 and of its deployment method can be envisaged. In particular, the guide line and the folding and closing lines may vary in arrangement, in geometry, and in number, to ensure the windsock folding step described. Furthermore, the guide line 9 can perform its traction function on the leading edge of the traction wing in different ways. It can for example be connected directly to the base platform, rather than to the flight path control device. It can also be permanently connected to a lashing line 20 which would be slidably connected to this guide line 9.

The folding step in windsock can also be implemented during the folding phase of the traction wing, to ensure a certain stability to the traction wing before folding, and to guarantee a more careful folding.

The path of the closure line along the traction wing, between its leading edge and its trailing edge, can be arranged differently, while ensuring the closure of the trailing edge during the folding step in windsock. The closing line may for example comprise a strand arranged along the trailing edge, that is to say on the periphery formed by the trailing edge during the windsock folding.

Claims

1. Method of deploying a tethered wing traction system, this tethered wing traction system comprising a traction wing (5) adapted to generate a traction force under the effect of the wind, and adapted to be deployed and folded with respect to a base platform (3) which is provided with a stowage mast (4), the traction wing (5) having: a trailing edge (17) which comprises two lateral portions (25) ; and a leading edge (16) which comprises a middle zone (15) and two lateral portions (19); this method comprising a step of taking off the traction wing (5) with respect to the securing mast (4), this method being characterized in that it comprises, before the step of taking off, a step of windsock folding of the traction wing (5), in which:

- the middle zone (15) of the leading edge (16) is maintained relative to the lashing mast (4) at a first height on the lashing mast (4);

- the lateral portions (19) of the leading edge (16) are held relative to the lashing mast (4) at least at a second height on the lashing mast (4), lower than said first height;

- the trailing edge (17) is closed by mutual approximation of the side portions (19) of the trailing edge (17).

2. Method according to claim 1, characterized in that the maintenance relative to the lashing mast (4) of the middle zone (15) of the leading edge (16) is achieved by pulling a line which is connected to the middle zone (15) of the leading edge (16).

3. Method according to one of the preceding claims, characterized in that the maintenance relative to the lashing mast (4) of the lateral portions (19) of the leading edge (16) is carried out by pulling fold lines (10A, 10B, 10C) which each have one end attached to the leading edge (16) being spaced apart along this leading edge (16).

4. Method according to claim 3, characterized in that the fold lines (10A, 10B, 10C) are arranged in symmetrical pairs, each fold line of a pair connecting the middle zone (15) of the leading edge ( 16) to another area of the leading edge (16), and in that the pulling of the fold lines (10A, 10B, 10C) is achieved by pulling together on the two lines of each pair of fold lines.

5. Method according to claim 4, characterized in that the holding relative to the lashing mast (4) of the lateral portions (19) of the leading edge (16) is carried out by pulling at least three pairs of folding lines (10A, 10B, 10C) symmetrical, following at least three heights along the lashing mast (4).

6. Method according to one of the preceding claims, characterized in that the closing of the trailing edge (17) is carried out by pulling at least one closing line (13) connected to the trailing edge (17).

7. Method according to claim 6, characterized in that, during the windsock folding step, the closure line (13) is gripped by a first carriage (12A) sliding along the lashing mast (4 ).

8. Method according to the preceding claim, characterized in that, during the windsock folding step, the folding lines (10A, 10B, 10C) are each gripped in a sliding manner by a carriage (12B, 12C, 12D ) located under the first carriage (12A).

9. Method according to one of claims 2 to 8, characterized in that said line which is connected to the middle zone (15) of the leading edge (16), is connected to the middle zone (15) by means (28), and is connected to the closure line (13), the windsock folding step comprising an operation of releasing or pulling the closure line (13), this operation comprising the following tasks:

- opening of the clamping means (28);

- release or traction of said which is connected to the middle zone (15) of the leading edge (16), causing a relaxation or traction on the closure line (13);

- closing the clamping means (28).

10. Captive wing traction system, comprising:

- a traction wing (5) adapted to generate a traction force under the effect of the wind, and adapted to be deployed and folded in relation to a base platform (3) which is provided with a stowage mast ( 4), the traction wing (5) having: a trailing edge (17) which comprises two lateral portions (25); and a leading edge (16) which comprises a middle zone (15) and two lateral portions (19);

- several fold lines (10A, 10B, 10C) each having one end fixed to the leading edge (16) being spaced apart from each other along this leading edge (16); this traction system being characterized in that it comprises:

- a line connected to the middle zone (15) of the leading edge (16);

- at least one closure line (13) connected to the trailing edge (17);

- a control unit (30) adapted to control a traction on the line which is connected to the middle zone (15), the folding lines (10A, 10B, 10C), and the closing line (13), this unit (30) comprising a windsock folding mode in which: the middle zone (15) of the leading edge (16) is maintained with respect to the stowage mast (4) at a first height on the mast stowage (4), by pulling the line which is connected to the middle zone (15); the lateral portions (19) of the leading edge (16) are held relative to the lashing mast (4) at at least a second height on the lashing mast (4), lower than said first height, by a pulling fold lines (10A,10B,10C); the trailing edge (17) is closed by mutual bringing together of the lateral portions (25) of the trailing edge (17), under the effect of traction of the closure line (13).

11. Traction system according to claim 10 characterized in that the fold lines (10A, 10B, 10C) are arranged in symmetrical pairs, each fold line of a pair connecting the median zone (15) of the leading edge (16) to another zone of the leading edge (16), and in that the pulling of the fold lines (10A, 10B, 10C) is carried out by pulling together on the two lines of each pair of fold lines.

12. Traction system according to one of claims 10 or 11, characterized in that it comprises carriages (12A, 12B, 12C, 12D) sliding along the lashing mast (4) adapted to grasp in a sliding manner the line which is connected to the middle zone (15) and the folding lines (10A, 10B, 10C), these trolleys (12A, 12B, 12C, 12D) being spaced from each other along the lashing mast ( 4) when the control unit (30) is in windsock folding mode.

13. Traction system according to one of claims 10 to 12, characterized in that the line which is connected to the middle zone (15) is connected to the middle zone (15) by a clamping means (28), and is connected to the closure line (13), the control unit (30) being adapted to control the clamping means (28) so that, when it is in its windsock folding mode, the control unit (30) is successively adapted to:

- open the clamping means (28);

- releasing or pulling the line which is connected to the middle zone (15), causing a release or a traction on the closure line (13);

- close the clamping means (28).

14. Traction system according to one of claims 10 to 13, characterized in that the closing line runs along the trailing edge (17) passing through rings (33).

15. Traction system according to claim 14, characterized in that the closing line (13) connects the two lateral portions (25) of the trailing edge (17).

16. Traction system according to claim 15, characterized in that the closing line (13) forms a loop between two rings (33) each arranged on a lateral portion (25) of the trailing edge (25).