Wingsail

Abstract

A wing for a wind-powered water supports has an inflatable supporting structure. The supporting structure includes a first support forming an arcuate leading edge of the wing, and a second support rearwardly spaced relative the first support. The second support has a larger cross-sectional area than the first support.

Description

“WINGSAIL”Field of the Invention

[0001] The present invention relates to a wingsail. It has been particularly developed in relation to an inflatable wingsail, such as one used in wingfoiling. It is anticipated that the sail may have further applications in other aquatic activities.Background to the Invention

[0002] Recent years have seen the growth of foilboarding, a water sport in which a user stands on a waterboard which in use locates above the water surface, being supported in the water by a foil structure, and being propelled by a hand-held sail or wing.

[0003] An example of such a wing is disclosed in US patent application publication number 20220119086. It includes an inflatable leading edge which is curved, and a boom extending transversely from a centre of the inflatable leading edge. A sail extends over the leading edge and boom and is used to catch the wing in order to propel a rider.

[0004] The inflatable leading edge of the wing provides the structural integrity of the wind, and therefore must be sufficiently strong to withstand tension of the sail. An increase in wind strength (or appropriate angling of the wing) results in a tendency for the leading edge to bend, which leads to a loss in shape for the wing. For this reason the leading edge must be sized appropriately to resist such bending.

[0005] A typical leading edge may have a diameter in the order of 200mm. Such a leading edge is resistant to bending, but presents in itself a source of drag.

[0006] The present invention seeks to provide an improved supporting structure for a wingsail.Summary of the Invention

[0007] According to one aspect of the present invention there is provided a wing for wind-powered water sports, the wing including an inflatable supporting structure arranged to support a canopy, the supporting structure including: a transversely extending boom being arranged to be held by a user; an arcuate first support defining a leading edge of the wing; and an arcuate second support, each of the first support and the second support extending laterally away from the boom, the second support being transversely spaced from the first support along the boom, the first support and the second support being fixed in position relative to each other, the first support having a generally cylindrical portion extending from the boom, the generally cylindrical portion of the first support having a first diameter, the second support having a generally cylindrical portion extending from the boom, the generally cylindrical portion of the second support having a second diameter, wherein the second diameter is larger than the first diameter. Advantageously, this allows for the canopy to form an aerofoil, with a suction side on an outer side of the boom having a different profile to a pressure side on an inner side of the boom.

[0008] It is anticipated that the canopy will form a relatively efficient aerofoil on both the first and second side compared to some other designs shown in the prior art. The extrados remains similar while the intrados can form a shape where the maximum thickness can be positioned far behind the leading edge (for instance, 10% to 60% of the distance along the boom) instead of being forced to sit at the leading edge, thus forming a profile with aerodynamic efficiency, lift and power.

[0009] The transversely extending boom may include a leading portion located between the first support and the second support, and a trailing portion extending from the second support, wherein the leading portion comprises 10% to 60% of the overall length of the transversely extending boom. Preferably, the leading portion comprises between 15% and 30% of the overall length of the boom. It is anticipated that a particularly usefulembodiment has a leading portion comprising about 20% of the overall length of the transversely extending boom.

[0010] The leading portion may have a larger cross sectional area than the trailing portion.

[0011] The first and second supports may be formed from arcuate members. Alternatively, the first and second supports may each be formed from generally cylindrical sections joined to form an arcuate shape. It is preferred that the second support has a larger radius of curvature than the first support.

[0012] It is preferred that the first support has outer ends, the second support has outer ends, and the outer ends of the second support are joined to the first support forwardly of the outer ends of the first support.

[0013] The first support and the second support may be connected by a plurality of struts. These struts may be arranged in a trussed configuration.

[0014] It is preferred that the canopy has a first side and a second side, the first side being located on an outer side of the boom and the second side being located on an inner side of the boom, the first side being convex and being more curved than the second side.

[0015] It is preferred that a gap between the first side and the second side varies along the transverse direction, with the maximum size of the gap being the diameter of the second support.

[0016] It is preferred that the second side extends in the transverse direction to a lesser extent than the first side. In a preferred embodiment the first side of the canopy extends from the leading edge of the wing to a trailing end of the boom, with the second side of the canopy extending from the leading edge of the wing to the second support.Brief Description of the Drawings

[0017] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:

[0018] Figure 1 is a view from an inner side of a rider using a wing sail in accordance with the prior art;

[0019] Figure 2 is a view from an outer side of a rider using a wing sail in accordance with the present invention;

[0020] Figure 3 is a partially cut-away view from the outer side of the rider and wing sail of Figure 2;

[0021] Figure 4 is a partially cut-away view from the inner side of the rider and wing sail of Figure 2;

[0022] Figure 5 is a side view of an alternative embodiment of a supporting structure within the wing sail of Figure 2;

[0023] Figure 6 is a schematic view of a cross-sectional profile of the wing sail of Figure 1 ; and

[0024] Figure 7 is a schematic view of a cross-sectional profile of the wing sail of Figure 2.Detailed Description of Preferred Embodiments

[0025] Referring to the Figures, Figure 1 shows a foil board 10 being used by a rider 12, the rider 12 carrying a prior-art wing sail 14.

[0026] The prior-art wing sail 14 has an arcuate leading edge support 16, a transverse boom 18, and a canopy 20.

[0027] Figures 2 to 5 show a wing sail 30 in accordance with the present invention. The wing sail 30 has an inflatable supporting structure 32 and a canopy 34.

[0028] The inflatable supporting structure 32 has a transverse boom 36 which defines a midline of the wing sail 30, the transverse boom 36 having a leading edge 38 and a trailing edge 40

[0029] The inflatable supporting structure 32 has a first support 42 which defines an arcuate leading edge 44 of the wing sail 30. The first support 42 extends away from the leading edge 38 of the transverse boom 36 in each of two transverse directions. The first support 42 is the same general shape as the arcuate leading edge support 16 of the prior-art wing sail 14, however has a substantially smaller cross-sectional diameter. A typical arcuate leading edge support 16 of the prior-art wing sail 14 has a cross-sectional diameter in the order of 200mm. By way of contrast, the first support 42 of the wing sail 30 shown in the drawings has a diameter in the order of 50mm.

[0030] In the embodiment shown in Figures 3 and 4, the first support 42 is formed by a plurality of generally cylindrical sections 45 which are joined at respective axial ends by angled joins in order to form the overall arcuate shape. It will be appreciated that in alternative embodiments, such as that shown in Figure 5, the arcuate shape could be formed by a continuously curved first support 42.

[0031] The first support 42 includes two first cylindrical portions 46 that are directly connected to the transverse boom 36, one on each lateral side.

[0032] The first support 42 curves through about 180°. The first support 42 has outer ends 47 which define trailing corners of the wing sail 30.

[0033] The wing sail 30 has a second support 48, located generally to the rear of the first support 42. The second support 48 is connected to the transverse boom 36 at an intermediate location 50, the intermediate locationbeing about 30% of the distance from the leading edge 38 and the trailing edge 40 of the transverse boom 36. It is anticipated that a useful result may be obtained by having the intermediate location between 10% and 80% of the distance from the leading edge 38 to the trailing edge 40.

[0034] The second support 48 extends away from the intermediate location 50 of the transverse boom 36 in each of two transverse directions. The second support 48 has two generally cylindrical second portions 52 that are directly connected to the transverse boom 36, one on each lateral side. The generally cylindrical second portions 52 are generally parallel to the first cylindrical portions 46.

[0035] The second support 48 is arcuate, but with a substantially reduced radius of curvature when compared with the first support 42. The second support 48 has outer ends 54 which are arranged to connect to the first support 42 at an outer lateral extent of the wing sail 30.

[0036] Supporting struts 56 extend between the first support 42 and the second support 48. In the embodiment of the drawings there are two supporting struts 56, each located about half of the lateral distance between the transverse boom 36 and a respective outer end 54 of the second support 48.

[0037] In an alternative embodiment (not shown), the struts 56 may be arranged to form a truss connecting the first support 42 with the second support 48. Alternatively, a plurality of struts 56 may be arranged in parallel along the lateral extent of the second support 48.

[0038] In the preferred embodiment of the drawings the transverse boom has a leading portion 58 extending between the leading edge 38 and the intermediate location 50, and a trailing portion 60 extending between the intermediate location 50 and the trailing edge 40. The leading portion 58 has a larger cross-sectional area that the trailing portion 60.

[0039] It will be appreciated that the transverse boom 36, the first support 42, the second support 48, and the struts 56 all lie generally in the same plane.

[0040] The second support 48 has a cross-sectional diameter significantly larger than the first support 42. In the embodiment shown, the cross- sectional diameter of the generally cylindrical second portions 52 is in the order of 100mm.

[0041] In the preferred embodiment each of transverse boom 36, the first support 42, the second support 48, and the struts 56 is inflatable. It will be appreciated that at least some of these members may be non-inflatable in alternative embodiments.

[0042] The canopy 34 extends from a first edge 62 defined by the trailing edge 40 of the transverse boom 36 and outer ends 47 of the first support 42; across an outer side of the supporting structure 32 over the second support 48; around the leading edge 44; and across an inner side of the supporting structure 32 to the second support 48.

[0043] It will be appreciated that the tension generated by the canopy 34 is largely absorbed by the second support 48. At the same time, the drag on the leading edge 44 of the wing sail 30 is largely determined by the diameter of the first support 42.

[0044] It will be appreciated that the canopy 34 forms an aerofoil, with an outwardly facing first side 64 being a suction side of the aerofoil and an inwardly facing second side 66 being a pressure side of the aerofoil.

[0045] As shown in Figure 6, the shape of the aerofoil made by the canopy 20 in the prior art is determined by the position of the arcuate leading edge support 16, the length of the boom 18 and the tension in the canopy 20.

[0046] In contrast, as shown in Figure 7, the shape of the aerofoil made by the canopy 34 is additionally determined by the relative size and position of the first support 42 and the second support 48.

[0047] It will be appreciated that alterations in the relative size and position of the first support 42 and the second support 48 can significantly affect the shape of the aerofoil made by the canopy 34, even when the boom 36 is of constant length. For instance, it will be understood that an off-set between the centres of the first support 42 and the second support 48 in the lateral direction results in larger curvature (and greater length) of the outwardly facing first side 64 compared to the inwardly facing second side 66. The degree of this is subject to variance. The combination of the off-set in the lateral direction and the diameters of the first and second supports 42, 48 will determine whether or not the inwardly facing second side 66 is generally concave or convex.

[0048] A gap 68 between the outwardly facing first side 64 and the inwardly facing second side 66 of the canopy 34 is the cross-sectional diameter of the first support 42 at the leading edge 44, and grows until it is the diameter of the second support 48.

[0049] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims

Claims1 . A wing 30 for wind-powered water sports, the wing 30 including an inflatable supporting structure 32 arranged to support a canopy 34, the supporting structure 32 including: a transversely extending boom 36 being arranged to be held by a user; an arcuate first support 42 defining a leading edge 44 of the wing 30; and an arcuate second support 48, each of the first support 42 and the second support 48 extending laterally away from the boom 36, the second support being 48 transversely spaced from the first support 42 along the boom 36, the first support 42 and the second support 48 being fixed in position relative to each other, the first support 42 having a generally cylindrical portion 46 extending from the boom 36 , the generally cylindrical portion 46 of the first support having a first diameter, the second support 48 having a generally cylindrical portion 52 extending from the boom, the generally cylindrical portion 52 of the second support having a second diameter, wherein the second diameter is larger than the first diameter.

2. A wing 30 for wind-powered water sports as claimed in claim 1 , wherein the transversely extending boom 36 includes a leading portion 58 located between the first support 42 and the second support 48, and a trailing portion 60 extending from the second support 48, the leading portion 58 comprising between 10% and 60% of the overall length of the transversely extending boom 36.

3. A wing 30 for wind-powered water sports as claimed in claim 2, wherein the leading portion 58 comprises between 15% and 30% of the overall length of the transversely extending boom 36.

4. A wing 30 for wind-powered water sports as claimed in claim 2, wherein the leading portion 58 comprises about 20% of the overall length of the transversely extending boom 36.

5. A wing 30 for wind-powered water sports as claimed in any one of claims 2 to 4, wherein the leading portion 58 has a larger cross sectional area than the trailing portion 60.

6. A wing 30 for wind-powered water sports as claimed in any preceding claim, wherein the first and second supports 42, 48 are formed from arcuate members.

7. A wing 30 for wind-powered water sports as claimed in any one of claims 1 to 5, wherein at least one of the first and second supports 42, 48 is formed from generally cylindrical sections joined to form an arcuate shape.

8. A wing 30 for wind-powered water sports as claimed in any preceding claim, wherein the second support 48 has a larger radius of curvature than the first support 42.

9. A wing 30 for wind-powered water sports as claimed in claim 8, wherein the first support 42 has outer ends 47, the second support 48 has outer ends 54, and the outer ends 54 of the second support 48 are joined to the first support 42 forwardly of the outer ends 47 of the first support 42.

10. A wing 30 for wind-powered water sports as claimed in any preceding claim, wherein the first support 42 and the second support 48are connected by a plurality of struts 56.11 .A wing 30 for wind-powered water sports as claimed in any preceding claim, wherein the canopy 34 has a first side 64 and a second side 66, the first side 64 being located on an outer side of the boom 36 and the second side 66 being located on an inner side of the boom 36, the first side 64 being convex and being more curved than the second side 66.

12. A wing 30 for wind-powered water sports as claimed in claim 11 , wherein a gap 68 between the first side 64 and the second side 66 varies along the transverse direction, with the maximum size of the gap 68 being the cross- sectional diameter of the second support 48.

13. A wing 30 for wind-powered water sports as claimed in claim 11 or claim 12, wherein the second side extends 66 in the transverse direction to a lesser extent than the first side 64.

14. A wing 30 for wind-powered water sports as claimed in claim 13, wherein the first side 64 of the canopy 34 extends from the leading edge 44 of the wing 30 to a trailing end 40 of the boom 36, with the second side 66 of the canopy 34 extending from the leading edge 44 of the wing 30 to the second support 48.

Images