FR2854869A1 - Towing wing with negative dihedral, e.g. for kite surfing, has transverse supple line to vary distance between ends of wing for enhanced stability - Google Patents

Abstract

The wing (18) consists of an inflatable structure (20) with a curved leading edge (22) and has a transverse line (70) connected to two points (72A, 72B) located symmetrically on opposite sides of the wing to draw them together. At least one of the points (72A, 72B) is in the form of a loop through which the line passes and is connected to a control line (44A, 44B). The wing's inflatable structure comprises a main tube (28) along its leading edge and a number of transverse tubes (30) scross it from the leading edge.

Description

The present invention relates to a negative dihedral propellant wing

  of the type comprising a blade delimiting a leading edge having a general shape curved towards the load to be towed.

  It is known to use propulsive wings, sometimes called "kites5 volants", for the traction or the lift of a load. Such propulsive wings are used in certain sliding sports, in particular aquatic sports. This is the case, for example, of the sport designated in English by "kite boarding", where a user has his feet connected to a board allowing him to glide over the surface of the water, while the user's body is connected to a propulsive wing, allowing it to move.

  Most propulsive wings currently used consist of a flexible canopy with a pronounced negative dihedral connected to the user by lines fixed to the lateral ends of the wing, that is to say that the lateral ends of the wing are located at a level below the mid range of the wing when in use. The wing then has an approximately semicircular shape facing downwards.

  A propellant wing of this type is described for example in document EP-0.202.271. This wing has the general shape of a spherical spindle. It comprises, along its leading edge, an inflatable main rod.

  The most efficient propulsive wings have a very long measured length between the two lateral ends compared to their width measured in the middle part between the leading edge and the trailing edge. However, this proportion of the wing leads to a lack of general rigidity of the wing. This lack of rigidity results in changes in the wingspan during the maneuvers performed by the user or when the wind changes force or direction. In extreme cases, the wing changes size in a continuous back and forth movement.

  In an attempt to stiffen the structure of the wings, it has been envisaged to increase the diameter of the main flange of the wing extending along the leading edge. However, this increase in diameter comes at the expense of performance due to the aerodynamic drag created by the flange.

  Other solutions have been considered such as the use of more stable materials, the increase in the paneling of the main tube or the increase in the pressure in the main tube.

  The invention proposes to remedy this problem of variation in stretch of the wing.

  To this end, the invention relates to a symmetrical propulsive wing of the aforementioned type, characterized in that it comprises at least one flexible return link stretched between two retaining points distant from the length of the leading edge, said link flexible exerting, along the leading edge, a restoring force of the two retaining points towards each other.

  According to particular embodiments, the propulsive wing comprises one or more of the following characteristics - it comprises an inflatable structure for supporting the airfoil, which structure comprises a main rod extending along the leading edge and transverse tubes connected to the main tube; - the two retaining points are arranged symmetrically with respect to the longitudinal axis of the wing; - the two retaining points are located between half and the lower quarter of the height of the wing; - It comprises, at each lateral end of the wing, at least one control line and the wing has a loop forming said first retaining point, and the flexible link is slidably engaged through the loop, at least one end the flexible link being linked to a control line of the wing, the other end of the flexible link being linked to the second retaining point; - It comprises, at each lateral end of the airfoil, at least one control line and the wing has two loops each forming a retaining point, and the flexible link is slidably engaged through each loop, the ends of the flexible link being each linked to a command line; - It comprises, at each lateral end of the wing, at least one control line and the wing has a loop forming a first retaining point, the flexible link is slidably engaged through the passer-by, and the link flexible comprises, at least at one end, a ring through which is slidably engaged a control line, a stop for stopping the ring being provided to limit the displacement of the ring along the length of the command line; - it comprises, at each end of the airfoil, at least one control line and the wing comprises two loops each forming a retaining point, the flexible link is slidably engaged through each passer-by, the flexible link comprises, at each end, a ring through which a control line is slidably engaged, a stopper for each ring being provided to limit the displacement of the ring along the length of the associated control line; and - the length of the flexible link is chosen to be greater than the length of the leading edge measured between the retaining points.

  The invention will be better understood on reading the description which will follow, given solely by way of example and made with reference to the drawings, in which - Figure 1 is an elevation view of a propulsion wing equipped with 'a control device according to the invention; - Figure 2 is an enlarged view of the propulsion wing; - Figure 3 is an enlarged view of the control device shown partially in section; - Figure 4 is a perspective view of a propulsion wing and its control device during a release phase of the propulsion wing; - Figure 5 is a view identical to that of Figure 3 of an alternative embodiment of the control device; - Figures 6 and 7 are views identical to that of Figure 2 of two alternative embodiments of a propulsive wing; and - Figure 8 is a perspective view of the wing of Figure 7, during a release phase.

  The propulsion equipment 10 shown in FIG. 1 is intended for pulling a load, such as an athlete whose feet are secured to a board. It comprises a propulsive wing 12 and a device for controlling the wing 14. The wing is connected by four lines 16 to the control device 14.

  As illustrated in FIG. 2 on a larger scale, the propulsive wing comprises a flexible wing 18 supported by an inflatable structure 20.

  The wing 18 has a leading edge 22 at the front and a trailing edge 24 at the rear. They both extend from one lateral end to the other of the wing. The airfoil 18 extends between the two edges 22, 24 to form a continuous left surface.

  The propulsive wing is dihedral negative, that is to say that it has, viewed from the front, an approximately semi-circular shape whose concavity is turned towards the suspended load. The middle part of the wing is wider than its lateral ends, so that the wing generally has a spindle shape. The leading edge 22 and the trailing edge 24 converge towards each other towards the lateral ends to form a truncated point. In the example considered, the ends of the trailing edge and of the leading edge are thus spaced at the lateral ends of the wing by about fifty centimeters and are connected to each other by a cord 26.

  The support structure 20 comprises an inflated main rod 28 extending along the length of the leading edge from one lateral end to the other of the wing. This sausage generally has the shape of a crescent moon. Its diameter is gradually decreasing from its median range towards its ends. The airfoil 18 is secured to the front along the inflated tube 28.

  Longers 30 are distributed regularly along the length of the main flange 28 and extend from the leading edge 22 to the trailing edge 24. They each consist of an inflated flange. These tubes are connected at their front ends to the main tube 28. The wing 12 is secured to the side members 30 over their entire length, these side members being located below the wing, that is to say on the side of the load to be towed.

  At the ends of the leading edges 22 and trailing edges 24, the propulsive wing comprises a member for connecting a control line serving for the suspension of the load to be towed. The ends fitted with these members are noted 32A, 32B, for the trailing edge, and 34A, 34B, for the leading edge.

  These organs consist for example of rings or straps sewn and closed in a loop. A control line is connected to each suspension member.

  As illustrated in FIG. 1, the control device 14 includes an operating bar 40, each end 41A, 41B of which is connected by control lines 42A, 42B to the ends 32A, 32B of the trailing edge of the propulsion wing.

  The bar 40 is intended to be retained at arm's length by the user.

  Two additional control lines 44A, 44B are linked to the ends 34A, 34B of the leading edge 22 of the wing. These two lines are formed of flexible strands which converge towards one another and engage through a single bore 46 formed through the bar 40 to be linked to the user's harness.

  More specifically, and as illustrated in FIG. 3, the control device 14 comprises a sheath 48 made up of a flexible tube of about sixty centimeters. The tube being self-supporting, that is to say that it is capable of holding vertically without collapsing under the effect of its own weight, even in the absence of any upper support and any other retaining forces. . The tube can however deform in bending under the action of a stress. This tube is formed for example of polyurethane.

  Its length is preferably between 50 cm and 120 cm.

  The sheath 48 is slidably mounted inside the bore 46. The sheath has, at its ends, stops 50, 52 adapted to cooperate with the bar 40 to prevent the sheath from being disengaged from the bore 46. The stops are formed for example of spherical protrusions with a diameter greater than the diameter of the hole 46.

  The lines 44A, 44B are both engaged inside the sheath 48. They penetrate from the side of the propulsive wing through an upper end of the sheath. They emerge at its other end. One of the 30 lines, for example the line 44B, is linked to the sheath 48, at a point 54 by any suitable means such as sewing, gluing, welding or a knot.

  Line 44B then forms a guide line.

  This line 44B is also secured by releasable connection means 56 to a stirrup 58 for connection to a harness worn by the user of the propulsive wing. Advantageously, the stirrup 58 is equipped with a swivel.

  The releasable connecting means 56 are of any suitable type. They are formed for example of a removable pin ensuring the connection between the end of the line 44B and the stirrup 58.

  Line 44A is slidably mounted inside the sheath 48. It then forms a sliding line relative to the sheath. Its end denoted 60 is permanently linked to the stirrup 58, for example by a knot. Preferably, however, according to a particular embodiment, the line 44A is connected to the stirrup 58 by releasable connection means independent of the connection means 56 ensuring the connection of the other line 44B to the stirrup.

  As illustrated in FIG. 2, the propulsive wing further comprises a flexible bracing link 70 applied between two points 72A, 72B of remote retaining points arranged along the length of the main rod 28. The length of the link 70 between these two points 72A , 72B fixes in flight the maximum spacing of the wing.

  The retaining points 72A, 72B are arranged symmetrically with respect to the longitudinal axis of the wing. They are advantageously located between the half and the lower quarter of the height of the propulsive wing.

  In the embodiment illustrated in FIG. 2, the two points 72A, 72B are each equipped with a ring linked to the main rod 28.

  The flexible link 70 consists for example of a cord. This cord is linked at a first end to point 72A, for example by being tied to the ring constituting this point.

  On the contrary, the link 70 is engaged in the ring 72B and is free to slide there.

  A complementary ring 74 is secured to the main flange at the end 34B of the leading edge on the side of the retaining point 72B. The link 30 70 is engaged there and is free to slide there.

  The link 70 is secured, for example by a node to the control line 44B at a point of attachment noted 76. In general, the length of the link 70 is chosen to be greater than the length of the main rod 28 measured between the retention points 72A, 72B. Preferably, the length of the link 70 is greater than the length of the main rod 28 measured between the points 72A and 34B.

  The position of the point 76 is determined as a function of the length of the link 70 so that, in flight, the link 70 is kept taut between the retaining points 72A, 72B, limiting their spacing to a predetermined maximum distance.

  Thus, in flight, the length of the link between the points 72A, 72B is equal to the maximum distance desired between these two points.

  The propulsion equipment illustrated in Figures 1 to 3 operates as follows.

  During normal use, the stirrup 58 is connected to the user's harness and the latter manually retains the bar 40. To maneuver the wing, the user moves the bar along the length of the sheath 48, doing so bas15 tilt the wing forward or backward.

  It is understood that the presence of the sheath 48, now the two lines 44A, 44B contiguous along the entire length of the sleeve, prevents that, during the movement of the bar 40, the lines 44A, 44B are stressed.

  Thus, the lines 44A, 44B not being subjected to friction, these do not undergo premature wear due to the movement of the bar.

  In the event of danger, the user releases the bar 40 and frees the connection means 56. Thus, the control line 44B is disconnected from the stirrup 58 from its lower end.

  Under the action of the wind, the wing is driven away from the user, so that the bar 40, the line 44B and the sleeve 48 which is integral therewith move away from the stirrup 58 as illustrated in Figure 4. On the other hand, the line 44A being always secured to the stirrup 58, the sheath 48 slides along the line 44A.

  As the propulsive wing is no longer retained except by line 44B, the latter 30 gradually collapses.

  The propulsive wing then flattens out and ceases to exert any force on the user still connected by the stirrup 58.

  During this flattening of the wing, the link 70 slides in the rings provided at the retaining point 72B and at point 74. The connection point 76 is thus brought back to the end 34B of the leading edge o is located the ring 74, the control line 44B forming a loop denoted 80 at the extremity of the leading edge.

  It is understood that, upon release, the link 70 which is held only by line 44B gradually relaxes and allows the flattening of the wing.

  On the contrary, during the normal use phases of the wing, and as illustrated in FIG. 2, the connection point 76 of the link 70 being maintained due to the tension of the control line 44B, the link 70 is kept taut and imposes a maximum distance between the retaining points 72A and 72B. The tension of the link 70 avoids the wingspan variations of the wing and the pumping phenomena which can be observed in the absence of such a line.

  As a variant, the ring 74 is eliminated and the flexible link 70 then directly connects the retaining point 72B and the attachment point 76.

  FIG. 5 shows an alternative embodiment of a control device for a propulsive wing. In this figure, elements identical or analogous to those of the embodiment of Figure 3 bear the same reference numbers.

  Only the differences from the other embodiment will be described.

  In this embodiment, the line 44A is not engaged through the sheath 48. On the contrary, the line 44A integrates the sheath, the kiln 48 and the current part of the line 44A being linked at a point 90 at the level of the stop 50. The other end of the sheath is linked to the stirrup 58 by the releasable connecting means 56. The line 44A crosses, for its part, the sheath 48 right through and is permanently linked to the stirrup 58.

  The control device of FIG. 5 operates in an analogous fashion to the device illustrated in FIG. 3, since, when the connection means 56 are released, the sheath, driven by line 44B, circulates along line 44A which slides inside the sheath.

  In this embodiment also, the line 44A not being in contact with the bar 40, any risk of premature wear of the line 44A is avoided. In addition, the line 44B being formed from the sheath at the level of the operating bar, and receiving the line 44A on this section, is also not subject to significant wear since it is not deformed during passage from the bar.

  According to yet another embodiment not shown, the guide line integral with the sheath consists of the first control line 44A. In this case, the line 44B is linked to the stirrup by releasable connecting means which, once released, allow the line 44B to be extracted from the sheath through which it is slidably mounted.

  In this case, during the release of the propulsive wing, the sheath, secured to the first line 44, remains linked to the stirrup. On the contrary, the second line 44B released is extracted from the sheath by being pulled by the propulsive wing. Likewise, the operating bar slides along the sleeve and emerges from it.

  In this embodiment, the sheath is devoid, at its upper end, of a retaining stop for the operating bar.

  Figures 6 and 7 show other alternative embodiments of a propulsive wing.

  The parts identical or analogous to the wing of FIG. 2 are designated by the same reference numbers.

  In the embodiment of FIG. 6, the link 70 is not linked to the retention point 72A. On the contrary, it is slidably engaged in the ring provided at the retaining points 72A and 72B. The link 70 extends beyond the retention point 72A. Its ends are linked to the control lines 44A and 44B at the attachment points 76, 86 arranged symmetrically to one another.

  In this case, the length of the link 70 is chosen to be greater than the length of the main flange 28 measured between the retention points 72A and 30 72B increased by the distance separating the retention point 72A from the attachment point 86.

  Preferably, the length of the link 70 is greater than the length of the main rod 28 measured between the points 72A and 34B increased by the distance separating the retaining point 72A from the attachment point 86.

  In this embodiment, the ring 74 is omitted, so that the link 70 extends directly from the retaining points 72A, 72B towards the attachment points of the control lines, respectively 76 and 86.

  Alternatively, the ring 74 is present as well as another identical ring provided at the end 34A. The link 70 is slidably engaged in these rings.

  In the case of normal use of the wing, the control lines 44A, 44B are tensioned, thus ensuring that the link 70 is tensioned, which then fixes a maximum spacing between the retaining points 72A, 72B.

  On the other hand, during an emergency dropping phase of the wing, and whatever the front line 44A or 44B which is released, the propulsive wing 15 flattens out, the link 70 being released from one of its ends.

  In FIG. 7 another embodiment of the propulsive wing is shown. In this embodiment, the link 70 is linked, at a first end, to the retaining point 72A. It is engaged through the ring of the retaining point 72B where it is free to slide.

  It has, at its other end, a ring 92 inside which the control line 44B is slidably engaged. The length of the link 70 is chosen equal to or greater than the length of the flange 28 measured between the retaining points 72A, 72B.

  However, in this particular embodiment, the link 70 can have a length equal to or even less than the length of the leading edge measured between the retaining points 72A, 72B.

  During normal use of the wing, the ring 92 is held in abutment at the end 34B of the leading edge which then forms a stop, so that the link 70 is kept taut between the two retaining points 72A, 72B, 30 limiting their spacing. For reasons of clarity, the ring is slightly offset from the end of the leading edge in Figure 7.

  On the other hand, in the event of an emergency release and while the line 44B is released, the wing flattens out, taking the configuration illustrated in FIG. 8.

  It is understood that the control line 44B being released, the latter deforms under the action of the traction of the link 70 exerted by the ring 92, so that the link 70 circulates in the loop provided at the retaining point 72B, until the ring 92 joins point 72B. In this configuration, the wing is flattened and is held only by line 44A.

  As a variant, the link 70 is not linked to the retention point 72A. On the contrary, it is equipped with a ring in which the link 70 is free to slide. At its end disposed beyond the ring 72A, the link 70 is equipped with a ring through which the control line 44A is slidably engaged.

  In this case, the length of the link 70 is chosen to be equal to or greater than the length of the flange 28 measured between the retaining points 72A, 72B, increased by the length separating the retaining point 72A from the end 34A of the leading edge .

  In this embodiment also, the end 34A of the leading edge forms a stop ensuring the stop of the ring provided at the end of the link and engaged around the control line 44A.

  Thus, one or other of the control lines 44A and 44B can be released to allow the emergency release of the sail. 20

Claims (9)

  1.- Propulsive wing (12) with a dihedral negative comprising a blade (18) delimiting a leading edge (22) having a general shape curved towards the load to be towed, characterized in that it comprises at least one sou5 pie link return (70) stretched between two distant retaining points (72A, 72B) the length of the leading edge (22), said flexible link (70) exerting, along the leading edge (22), a force of recall of the two retention points (72A, 72B) towards each other.   2. A propulsive wing according to claim 1, characterized in that it comprises an inflatable structure (20) for supporting the airfoil (18), which structure comprises a main rod (28) extending along the edge of attack (22) and transverse tubes (30) connected to the main tube (28).   3. A propulsive wing according to claim 1 or 2, characterized in that the two retaining points (72A, 72B) are arranged symmetrically with respect to the longitudinal axis of the wing.   4. A propulsive wing according to any one of the preceding claims, characterized in that the two retaining points (72A, 72B) are located between the half and the lower quarter of the height of the wing.   5. A propulsive wing according to any one of the preceding claims, characterized in that it comprises, at each lateral end of the wing (18), at least one control line (44A, 44B) and the wing comprises a loop (72B) forming said first retaining point, and in that the flexible link (70) is slidably engaged through the loop 25 (72B), at least one end of the flexible link (70) being linked to a line (44B) for controlling the wing, the other end of the flexible link (70) being linked to the second retaining point (72A).   6.- propulsive wing according to one of claims 1 to 4, characterized in that it comprises, at each lateral end of the airfoil (18), at least one control line (44A, 44B) and the wing comprises two loops each forming a retaining point (72A, 72B), and in that the flexible link (70) is slidably engaged through each passer-by, the ends of the flexible link (70) each being linked to a line control (44A, 44B).   7.- Wing according to one of claims 1 to 4, characterized in that it comprises, at each lateral end of the airfoil (18), at least 5 a control line (44A, 44B) and the wing comprises a passer-by (72B) forming a first retaining point, in that the flexible link (70) is slidably engaged through the passer-by, and in that the flexible link comprises, at least at one end, a ring (92 ) through which is slidably engaged a control line (44B), a stop 10 (34B) for stopping the ring (90) being provided to limit the movement of the ring along the length of the command line (44B).   8. A wing according to any one of claims 1 to 4, characterized in that it comprises, at each end of the wing (18), at least one control line (44A, 44B) and the wing comprises two passers-by each forming a retaining point (72A, 72B), in that the flexible link (70) is slidably engaged through each pass-through (72A, 72B), and in that the flexible link (70) comprises , at each end, a ring (92) through which is slidably engaged a control line (44A, 44B), a stop (34A, 34B) for stopping each ring (92) 20 being provided for limit the movement of the ring (92) along the length of the associated control line (44A, 44B).   9. Wing according to any one of the preceding claims, characterized in that the length of the flexible link (70) is chosen to be greater than the length of the leading edge (22) measured between the retaining points (72A, 25 72B ).