Hydro Foil Having One or More Wings with Dual in Line Protrusions with Continuous Leading Edge

Abstract

A hydro foil for use with a strut extending from a watercraft hull. The hydro foil includes a fuselage extending along a longitudinal axis. The fuselage is distally attachable to the strut. The hydro foil further includes a lifting foil having first and second lifting. The wings each have first and second protrusions both longitudinally arrayed along the fuselage. The first and second protrusions connect at an apex to form a loop. The first protrusion has a first protrusion leading edge and a first protrusion trailing edge. The second protrusion has a second protrusion leading edge and a second protrusion trailing edge. The first and second leading edges forming a continuous foil leading edge and the first and second trailing edges forming a continuous foil trailing edge. The first protrusion trailing edge is disposed between the first protrusion leading edge and the second protrusion leading edge.

Claims

1. A hydro foil for use with a strut extending from a watercraft hull, the hydro foil comprising: a generally elongate fuselage extending along a fuselage longitudinal axis, the fuselage being distally attachable to the strut; and a lifting foil having first and second lifting wings each attached to and extending opposite from each other from the fuselage, each of the first and second lifting wings having first and second protrusions both longitudinally arrayed along the fuselage, the first and second protrusions connecting at an apex to form a loop, the first protrusion having a first protrusion leading edge and a first protrusion trailing edge, the second protrusion having a second protrusion leading edge and a second protrusion trailing edge, the first and second leading edges forming a continuous foil leading edge and the first and second trailing edges forming a continuous foil trailing edge, the first protrusion trailing edge being disposed between the first protrusion leading edge and the second protrusion leading edge.

2. The hydro foil of claim 1 wherein each of the first and second protrusions is generally flat and elongate and extends from the fuselage with the width of each of the protrusions extending longitudinally along the fuselage and having a relatively smaller thickness in a direction orthogonal to the fuselage longitudinal axis of the fuselage in comparison to the width.

3. The hydro foil of claim 1 wherein each of the first protrusions has a first protrusion topside surface and a first protrusion downside surface generally facing in a direction opposite from the first protrusion topside surface, each of the second protrusions has a second protrusion topside surface and a second protrusion downside surface generally facing in a direction opposite from the second protrusion topside surface.

4. The hydro foil of claim 3 wherein the first protrusion topside surface generally faces in same direction as the second protrusion topside surface, and the first protrusion downside surface generally faces in a same direction as the second protrusion downside surface.

5. The hydro foil of claim 4 wherein the first protrusion topside surface is more curved along an axis orthogonal to the fuselage longitudinal axis relative to the curvature of the first protrusion downside surface, the second protrusion topside surface is more curved along an axis orthogonal to the fuselage longitudinal axis relative to the curvature of the second protrusion downside surface.

6. The hydro foil of claim 1 wherein the first protrusion and the second protrusions are attached to the fuselage along the fuselage longitudinal axis in different parallel planes.

7. The hydro foil of claim 1 wherein the fuselage has a strut attachment region for attaching the hydro foil to the strut, the second protrusion is disposed between the first protrusion and the strut attachment region in a direction along fuselage longitudinal axis.

8. The hydro foil of claim 1 further includes a down pulling foil having first and second down pulling foil wings each attached to and extending opposite from each other from the fuselage.

9. The hydrofoil of claim 8, wherein the first and second down pulling foil wings each having distal ends, the distal ends being a distance from the fuselage longitudinal axis less than a distance of the apex of each of the first and second lifting wings from the fuselage longitudinal axis.

10. The hydro foil of claim 8 wherein the lifting foil is attached to the fuselage with the second protrusions disposed between the first protrusions and the down pulling foil along the fuselage longitudinal axis.

11. The hydro foil of claim 8 wherein the lifting foil is attached to the fuselage with the first protrusions disposed between the second protrusions and the down pulling foil along the fuselage longitudinal axis.

12. The hydro foil of claim 1 wherein the fuselage has a forward end and an opposing aft end, the fuselage further has a strut attachment region for attaching the hydro foil to the strut, the lifting foil is disposed between the forward end and the strut attachment region along the fuselage longitudinal axis.

13. The hydro foil of claim 1 wherein the fuselage has a forward end and an opposing aft end, the first and second lifting wings are angled with each apex of the first and second protrusions positioned aft of where the protrusions extend from the fuselage with respect to the fuselage longitudinal axis.

14. A watercraft comprising: a watercraft hull; a strut extending downward from the watercraft hull; and a hydro foil including: a generally elongate fuselage extending along a fuselage longitudinal axis, the fuselage being distally attached to the strut; and a lifting foil having first and second lifting wings each attached to and extending opposite from each other from the fuselage, each of the first and second lifting wings having first and second protrusions both longitudinally arrayed along the fuselage, the first and second protrusions connecting at an apex to form a loop, the first protrusion having a first protrusion leading edge and a first protrusion trailing edge, the second protrusion having a second protrusion leading edge and a second protrusion trailing edge, the first and second leading edges forming a continuous foil leading edge and the first and second trailing edges forming a continuous foil trailing edge, the first protrusion trailing edge being disposed between the first protrusion leading edge and the second protrusion leading edge.

15. The hydro foil of claim 14 further includes a down pulling foil having first and second down pulling foil wings each attached to and extending opposite from each other from the fuselage.

16. The hydro foil of claim 14 wherein the strut is a lifting foil strut, the hydro foil further including a down pulling foil strut extending downward from the watercraft hull, the down pulling foil strut having a down pulling foil strut distal end, the hydro foil further includes a down pulling foil having first and second down pulling foil wings each attached to and extending opposite from each other from the down pulling foil strut at the down pulling foil distal end.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

[0011] FIG. 1 is a perspective rear view of a hydro foil attached to a strut according to an embodiment, with water flow lines shown in dashed lining;

[0012] FIG. 2 is a front view of the hydro foil and strut of FIG. 1;

[0013] FIG. 3 is a front view of the hydro foil and strut of FIG. 2 shown as attached to a watercraft hull of a watercraft and a water line indicated in the rippled dashed lining;

[0014] FIG. 4 is a top view of the hydro foil and strut of FIG. 1;

[0015] FIG. 5 is a side view of the hydro foil and strut of FIG. 1;

[0016] FIG. 6 is a perspective rear view of a hydro foil attached to a strut according to another embodiment;

[0017] FIG. 7 is a perspective rear view of a hydro foil attached to a strut according to another embodiment;

[0018] FIG. 8 is a front view of the hydro foil and strut of FIG. 7;

[0019] FIG. 9 is a top view of the hydro foil and strut of FIG. 7;

[0020] FIG. 10 is a side view of the hydro foil and strut of FIG. 7;

[0021] FIG. 11 is a perspective rear view of a hydro foil attached to a strut according to another embodiment;

[0022] FIG. 12 is a front view of the hydro foil and strut of FIG. 7;

[0023] FIG. 13 is a top view of the hydro foil and strut of FIG. 7;

[0024] FIG. 14 is a side view of the hydro foil and strut of FIG. 7;

[0025] FIG. 15 is a perspective view of a watercraft according to another embodiment;

[0026] FIG. 16 is a side view of the watercraft of FIG. 15;

[0027] FIG. 17 is a front view of the watercraft of FIG. 15;

[0028] FIG. 18 is a pressure map of a hydro foil of an embodiment;

[0029] FIG. 19 is a pressure map of a standard lifting foil.

DETAILED DESCRIPTION

[0030] The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments. It is further understood that the use of relational terms such as top and bottom, first and second, and the like are used solely to distinguish one entity from another without necessarily requiring or implying any actual such relationship or order between such entities.

[0031] According to an aspect of the invention, with reference to FIGS. 1-5, there is provided a hydro foil 10 for use with a strut 12 extending from a watercraft hull 16 of a watercraft 14. The hydro foil 10 includes a generally elongate fuselage 18 extending along a fuselage longitudinal axis 20. The fuselage 18 is distally attachable to the strut 12. The hydro foil 10 further includes a lifting foil 26 having first and second lifting wings 28, 30 each attached to and extending opposite from each other from the fuselage 18. Each of the first and second lifting wings 28, 30 have first and second protrusions 32, 34 both longitudinally arrayed along the fuselage 18. The first and second protrusions 32, 34 connect at an apex 36 to form a loop. The first protrusion 32 has a first protrusion leading edge 38 and a first protrusion trailing edge 40. The second protrusion 34 has a second protrusion leading edge 42 and a second protrusion trailing edge 44. The first and second leading edges 38, 42 forming a continuous foil leading edge 46 and the first and second trailing edges 40, 44 forming a continuous foil trailing edge 48. The first protrusion trailing edge 40 is disposed between the first protrusion leading edge 38 and the second protrusion leading edge 42.

[0032] By forming a continuous loop without traditional wingtips, the hydro foil design eliminates most of the typical wingtip vortices in a conventional wing design, which are a primary source of induced drag and energy loss. This leads to improved hydrodynamic efficiency, greater stability in turbulent water and smoother water flow. The closed geometry also provides natural yaw stability. Having continuous foil leading edge 46 forming a loop distributes structural loads more evenly, resulting in a strong, rigid wing design that can potentially be lighter for a given strength and allows for a higher aspect wing than a traditional design which will increase the overall efficiency. Additionally, the compact form factor allows a large lifting area within a smaller overall wing span with a higher aspect ratio to improve lift-to-drag performance, particularly at low speeds.

[0033] As used herein, the term watercraft 14 refers to a broad class of waterborne devices, including but not limited to boats, ships, catamarans, floats, paddleboards, wind surfing boards, kite boards, and other similar recreational and transportation equipment. The term watercraft hull 16 refers to the downward facing side or portion of the associated watercraft 14 that is typically exposed to water.

[0034] As mentioned above, the fuselage 18 is distally attachable to the strut 12. In this respect the fuselage 18 may include a strut attachment region 62 which is located along a topside of the fuselage 18. The strut 12 extends downward from a bottom facing side of the watercraft hull 16. The distal end of the strut 12 is attachable to the fuselage 18 at the strut attachment region 62 according to any of those methods and components which are well known to one of ordinary skill in the art. The first and second lifting wings 28, 30 extend laterally in opposite directions from fuselage 18 and generally orthogonal to the fuselage longitudinal axis 20.

[0035] According to various embodiments, the fuselage has a forward end 22 and an opposing aft end 24. It is contemplated that the direction of travel of the associated watercraft 14 would result in the attached fuselage 18 and overall hydrofoil 10 also traveling in a direction from the aft end 24 toward the forward end 22 of the fuselage 18 along the fuselage longitudinal axis 20. As such, the first and second protrusion leading edges 38, 42 and the continuous foil leading edge 46 facing in a same direction as the forward end 22 and away from the aft end 24. The first and second protrusion trailing edges 40, 44 and the continuous foil trailing edge 48 facing in a same direction as the aft end 24 and away from the forward end 22. With reference to FIGS. 1 and 5, flow lines 70 symbolically indicate anticipated water flow with respect to the hydro foil 10 when traveling through water.

[0036] The first protrusion 32 may have a first protrusion topside surface 50 and an opposing first protrusion downside surface 52 generally facing in a direction opposite from the first protrusion topside surface 50, and the second protrusion 34 may have a second protrusion topside surface 54 and a second protrusion downside surface 56 generally facing in a direction opposite from the second protrusion topside surface 54. Further, the first protrusion 32 may have a first protrusion base 58 and the second protrusion 34 may have a second protrusion base 60. The first protrusion topside surface 50 may generally face in same direction as the second protrusion topside surface 54, and the first protrusion downside surface 52 may generally face in a same direction as the second protrusion downside surface 56. The first and second protrusions 32, 34 extend from the fuselage 18 with the first and second protrusion bases 58, 60 are attached to the fuselage 18 according to any of those methods and components which are well known to one of ordinary skill in the art. In this regard, from the first protrusion base 58, the first protrusion topside surface 54 extends to the apex 36 and then transitions to the second protrusion downside surface 56 to the second protrusion base 60. Similarly, from the first protrusion base 58, the first protrusion downside surface 54 extends to the apex 36 and then transitions to the second protrusion topside surface 55 to the second protrusion base 60.

[0037] Each of the first and second protrusions 32, 34 may be generally flat and elongate and extend from the fuselage with the width of each of the protrusions 32, 34 extending longitudinally along the fuselage 18 and have a relatively smaller thickness in a direction orthogonal to the fuselage longitudinal axis 20 of the fuselage 18 in comparison to the width. The first protrusion topside surface 50 may be more curved along an axis orthogonal to the fuselage longitudinal axis 20 relative to the curvature of the first protrusion downside surface 52, and the second protrusion topside surface 54 may be more curved along an axis orthogonal to the fuselage longitudinal axis 20 relative to the curvature of the second protrusion downside surface 56. Such topside curvature design is contemplated to create pressure differential adjacent the top and bottom sides of the first and second lifting wings 28, 30. This arrangement is contemplated to produce an aerodynamic effect (like an airplane wing) to result in a relatively low pressure disposed adjacent the first and second protrusion topside surfaces 50, 54 (producing an aerodynamic lift) and a relative high pressure adjacent the first and second bottom side surfaces 52, 56. This results in hydro foil 10 providing an upward force upon the strut 12 for lifting the watercraft 14 and watercraft hull 16.

[0038] The first protrusion 32 and the second protrusions 34 may be attached to the fuselage 18 along the fuselage longitudinal axis 20 in different parallel planes. In this respect, the first protrusion base 58 may be attached to the fuselage 18 above where the second protrusion base 60 is attached to the fuselage 18. This can best be seen in the side view of FIG. 5. In this embodiment the first and second wings 28, 30 are positioned forward adjacent the forward end 22 of the fuselage 18. The first and second wings 28, 30 may be disposed forward of the strut attachment region 62 in a direction along the fuselage longitudinal axis 20. The second protrusion may be disposed between the first protrusion 32 and the strut attachment region 62 in a direction along the fuselage longitudinal axis 20. As such, the continuous foil leading edge 48 is in a forward position.

[0039] The hydro foil 10 may further include a down pulling foil 64 having first and second down pulling foil wings 66, 68. The first and second down pulling foil wings 66, 68 are each attached to and extending opposite from each other from the fuselage 18. The first and second down pulling foil wings 66, 68 may be for a more conventional design with the first and second down pulling foil wings 66, 68 having a generally planar shape. The down pulling foil 64 is configured to have an aerodynamic configuration to have a relatively high pressure adjacent the topside and low pressure adjacent the bottom side to result in a downward pulling force upon the fuselage 18 and the attached strut 12. This may be achieved through a combination of the surface configuration and angular orientation of the first and second down pulling foil wings 66, 68 according to any of those construction and design methods which are well known to one of ordinary skill in the art. The lifting foil 26 may be attached to the fuselage 18 with the second protrusions 34 disposed between the first protrusions 32 and the down pulling foil 64 along the fuselage longitudinal axis 20. In the embodiment depicted, the down pulling foil 64 is aft of the lifting foil 26 and the strut attachment region 62. As the lifting foil 26 is position forward of the strut attachment region 62, it is contemplated the associated lifting force creates a torque upon the strut 12 adjacent the strut attachment region 62. To counteract such toque the down pulling foil 64 may be configured to impart an opposing torque while a net upward force is still being applied to the strut 12.

[0040] The first and second down pulling foil wings 66, 68 may each have distal ends, and the distal ends are a distance from the fuselage longitudinal axis less than a distance of the apex of each of the first and second lifting wings from the fuselage longitudinal axis. In this regard, the wingspan of the lifting foil 26 may be larger than the down pulling foil 64.

[0041] The hydro foil 10 and down pulling foil 64 may be constructed of materials and according to any of those methods which are well known to one of ordinary skill in the art. For example, the hydro foil 10 may be formed of a thermoplastic resin through a plastic injection molding process. Further, the first and second lifting wings 28, 30 may be form of various different materials and may be differing resins and include inserts, such as a pre-preg fiber infused sheet to result in a laminated or multilayered construction. The first and second lifting wings 28, 30 may be formed of different materials than the fuselage 18. The fuselage 18 may be itself buoyant, based upon the material selection and/or design, which may include having hollow regions.

[0042] Referring now to FIG. 6 there is another embodiment. Same reference numbers are used to indicate similar structures with differences noted. In this embodiment, there is provided a hydro foil 10 having a lifting foil 26 and a down pulling foil 64. The lifting foil 26 is similar in construction to the lifting foil 26 discussed above, but positioned adjacent the aft end 24 of the fuselage 18. The down pulling foil 64 is similar in construction to the down pulling foil 64 discussed above, but positioned adjacent the forward end 22 of the fuselage 18. The lifting foil 26 may be attached to the fuselage 18 with the first protrusions 32 disposed between the second protrusions 34 and the down pulling foil 64 along the fuselage longitudinal axis.

[0043] Referring now to FIG. 7-10 there is another embodiment. Same reference numbers are used to indicate similar structures with differences noted. In this embodiment, there is provided a hydro foil 74. The hydro foil 74 includes a lifting foil 76 that is positioned adjacent the forward end 22 of the fuselage 18. A lifting foil 26 is positioned adjacent the aft end 24 of the fuselage 18 similar in configuration as depicted in the embodiment of FIG. 6. The lifting foil 76 includes first and second lifting wings 78, 80 each with a first protrusion 82, a second protrusion 84 and an apex 86. The lifting foil 76 is generally similar to the lifting foil 26. However, in this embodiment, the first and second lifting wings 78, 80 are angled with each apex 86 of the first and second protrusions 82, 84 positioned aft of where the first and second protrusions 82, 84 extend from the fuselage 18 with respect to the fuselage longitudinal axis 20.

[0044] Referring now to FIG. 11-14 there is another embodiment. Same reference numbers are used to indicate similar structures with differences noted. In this embodiment, there is provided a hydro foil 74 that includes the lifting foil 26 and a lifting foil 76. The lifting foil 76 is similar to the lifting foil 76 discussed above, however, positioned adjacent the aft end 24 of the fuselage 18.

[0045] Referring now to FIG. 15-17 there is another embodiment. Same reference numbers are used to indicate similar structures with differences noted. In this embodiment, there is provided a watercraft 14 with a watercraft hull 16. The watercraft 14 is of an outrigger catamaran configuration with the watercraft 14 including an outrigger float 88. In this embodiment, there is provided a hydro foil 90, a down pulling foil 92, a hydro foil 94, and a down pulling foil 96. The hydro foil 90 is connected to the outrigger float 88 via a strut 98. The down pulling foil 92 is also connected to the float 88 via a down pulling strut 100. The hydro foil 94 is directly attached to the watercraft hull 16 and the down pulling foil 96 is attached to the watercraft hull 16 via a down pulling strut 102. The hydro foil 90 may be similar as discussed above as the hydro foil 10, 10, 74 and 74. The down pulling foil 92 and the down pulling foil 96 may be similar as discussed above as the down pulling foil 64, 64. Unlike the embodiments discussed above, it is understood the lifting foil and down pulling foil need not be commonly extend from a same fuselage.

[0046] Referring now to FIGS. 18 and 19 there are depicted computer analyzed pressure maps in relation to a hydro foil with a continuous leading edge design, such as hydro foil 10, in FIG. 18 and a traditional or standard rectangular foil wing in FIG. 19. FIG. 19 shows far more turbulence being released from the front wing on the standard wing vs FIG. 18 where there is less turbulence from the first protrusion which creates a much better lift over drag ratio and contributes to a more efficient design over all angles of attack.

[0047] The particulars shown herein are by way of example only for purposes of illustrative discussion, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the various embodiments set forth in the present disclosure. In this regard, no attempt is made to show any more detail than is necessary for a fundamental understanding of the different features of the various embodiments, the description taken with the drawings making apparent to those skilled in the art how these may be implemented in practice.