WO2023118210A1

WO2023118210A1 - Rhombohedral hydrofoil and craft comprising same

Info

Publication number: WO2023118210A1
Application number: PCT/EP2022/087089
Authority: WO
Inventors: François VARIGAS
Original assignee: Fly-R
Priority date: 2021-12-20
Filing date: 2022-12-20
Publication date: 2023-06-29
Also published as: FR3130738A1

Abstract

The rhombohedral hydrofoil (20) for a craft travelling parallel to an axis (46) has a plane of symmetry and comprises front wings (21, 22) that are connected to one another and rear wings (25, 26) that are connected to one another. The end of each front wing that is furthest from the junction of the front wings with one another is connected to one end of a rear wing which is the end furthest from the junction of the rear wings with one another. This assembly of wings has a first orthogonal projection onto a plane referred to as "vertical" perpendicular to the axis of travel, this projection having the shape of a quadrilateral having an obtuse angle at the junction of the front wings with one another, an obtuse angle at the junction of the rear wings with one another, and two acute angles at the junction of a front wing with a rear wing. This assembly of wings has a second orthogonal projection onto a plane referred to as "horizontal" orthogonal to the plane of symmetry and having an axis parallel to the axis of travel, this projection having the shape of a quadrilateral having only angles with magnitudes smaller than 180 degrees.

Description

RHOMBOEDRIC HYDROFOIL AND BOAT COMPRISING IT

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a rhombohedral hydrofoil and a boat comprising it. It applies, in particular, to sailboards, surfboards and boats with one or more hulls, sailing and/or motor.

STATE OF THE ART

A craft is a floating construction (boat) navigating by sail, rowing or motor. In fluid mechanics, a hydrofoil is a wing positioned under the boat and profiled so as to generate, by its displacement in the water, a lift force which acts on its speed and its stability. In the field of boating, the speed of movement generates on the hydrofoil(s) a hydrodynamic lift capable of lifting the hull(s) of the boat partially or totally out of the water. The purpose of this lift transfer is to reduce hull or float drag (friction and waves) and to reduce the power needed at cruising speed.

In the case of completely submerged hydrofoils, the airfoil is completely and constantly submerged. The advantage of this configuration is its ability to isolate the boat from the effect of the waves as soon as its speed is sufficient, so that the ship takes off, and the swell is not too strong. The supports or uprights or "legs" that connect the hydrofoils to the hull generally do not contribute lift. This configuration with submerged hydrofoils can have a higher efficiency (lift/drag) but is not naturally stable in pitch and roll. On the other hand, the lifting surface is constant whatever the speed and height of flight. Without a regulation system, nothing stabilizes the depth of immersion: the hydrofoil can arrive at the air/water interface. For these two reasons the ship must be equipped with an active stabilization system controlled by altitude sensors (as on the Moth hydrofoil) or by a control unit (altitude sensors, accelerometers). To vary the longitudinal and transverse lifts according to the speed, the turn radius requested and the weight of the boat, the hydrofoils must be equipped with a lift variation system acting on the setting or the camber of the profile or on the local flow. In this family, we most often find inverted “T” hydrofoils, but also “U” or “L” hydrofoils.

On monohulls, it is necessary to have a hydrofoil on each side in order to create "lift" on the side where the boat leans. For reasons of stability and/or significant mechanical constraints, this reduces the optimization of their placement as well as the shape of their design, and therefore their overall performance. This location and their shape make them more fragile and above all very exposed to all floating bodies. Because of these constraints, the drag generated by these hydrofoils is relatively high compared to the gains generated and limits their overall benefit.

As opposed to aircraft wings (for example described in documents WO 2018/158 549, CN 107 097 952 and US 2010/051 755) the hydrofoils of small boats, such as sailboards and surfboards, have a forward profiled wing (generating uplift) and a rear spoilered wing (generating lift down there) in order to generate a torque which compensates for that of the weight of the boat with passenger(s).

The document US2014/0209006 describes a drift configured to ensure lateral stability. This drift has four trapezoidal flaps (“sidewall”) whose longitudinal extension parallel to the flow axis decreases as a function of the distance from the base of the drift. These four flaps surround an opening having, in view along this axis, the shape of a quadrilateral. Seen from the side, the flaps extend towards the rear of the board and the lower flaps have, in relation to a vertical plane perpendicular to the axis of flow, a greater angle than that of the upper flaps. The sections of the upper flaps are provided to have a load-bearing profile and those of the lower flaps to have a spoiler profile.

PRESENTATION OF THE INVENTION

The present invention aims to remedy all or part of these drawbacks.

To this end, according to a first aspect, the present invention relates to a hydrofoil according to claim 1. The inventor has discovered that this form of hydrofoil has particularly interesting technical characteristics and effects. For example, such a hydrofoil with a wingspan of 1.5 meters can lift six tons at a speed of 35 knots. With a rhombohedral hydrofoil, the speed of the boat is increased and/or the power required to reach this speed is reduced.

By using a rhombohedral hydrofoil it is possible to mount it at the end of the keel and thus benefit from the mounting on cylinders it has, optimizing the total drag of the boat. By using control surfaces on the different surfaces of the rhombohedral hydrofoil it is possible to generate lift adapted to the conditions/needs of navigation. It is also possible to generate differential forces that can influence and/or control the stability of the boat. On a multihull and/or on a monohull with two parallel keels, the greater stability not only makes it possible to have two rhombohedral hydrofoils working together but also to limit the heeling effects, thus simplifying the design of the hulls and better distribution of the loads and stresses on the entire structure.

In embodiments, the hydrofoil object of the invention further comprises a body comprising:

- a clip for the lower mast of the boat,

- a support for the root and junction of the front wings and

- a support for the root and junction of the rear wings, the front and rear wing root supports being positioned respectively, on either side of this body in the plane of symmetry of the hydrofoil.

The body thus ensures the rigidity of the hydrofoil and makes it possible to reduce the thickness of the wings.

In embodiments, the body of the hydrofoil includes a ballast. The hydrofoil thus has a dual function.

In embodiments, the body of the hydrofoil includes ballast. The ballast can thus be emptied when the hull of the boat rises. In some embodiments, the hydrofoil which is the subject of the invention comprises, at least on each wing of a pair of wings, at least one flap actuated by an actuator. Thanks to these provisions, an active stabilization system of the boat is particularly effective.

In embodiments, at each junction of the front and rear wing tips is positioned a vertical closing surface of these wing tips. These vertical closing surfaces of the wing tips reduce the drag of the wing.

In embodiments,

- one end of each front wing is hinged to one end of a rear wing and

- at least one of the wing root supports is movable along the body of the hydrofoil.

Thus, the area of use and the overall performance of the hydrofoil and the boat are significantly enlarged. The hydrofoil that is the subject of the invention has a rhombohedral-type sail whose front wings and rear wings have variable geometry while remaining joined at their ends to obtain very different shapes.

In some embodiments, the length of the rear wings is strictly less than the length of the front wings, the angle formed between the main longitudinal axis of the body of the hydrofoil and the main axis of the rear wings being consequently, in all operating configurations, more obtuse than the angle formed between the main longitudinal axis of the hydrofoil body and the main axis of the front wings. Thanks to these arrangements, the front wings are always in the arrow configuration and the rear wings can assume an inverted, straight arrow configuration, that is to say perpendicular to the body of the hydrofoil, or in a non-inverted arrow, as well than in all intermediate configurations.

In embodiments, at least one of the wing root supports is configured to approach the other wing root support so that the front wings form the hypotenuses of right triangles formed by the front wings, the rear wings and the body of the hydrofoil, the main axis of each of the rear wings being, in these right-angled triangles, perpendicular to the main longitudinal axis of the body of the hydrofoil.

In embodiments, at least one of the wing root supports is configured to approximate the other wing root support so that the front wings and rear wings are swept, not inverted. Thanks to these provisions, the deflection of the front wings can be increased and the wingspan reduced, in particular for flight configurations at higher speeds.

In embodiments, at least one of the wing root supports is configured to splay away from the other wing root support so that the wingspan of the hydrofoil is less than the sum of four times the maximum width of the front wings and the rear wings, on the one hand, and the width of the body of the hydrofoil, on the other hand.

In particular embodiments, each of the wing root supports is movable along the body of the hydrofoil. Thanks to these provisions, the geometric configuration of the airfoil can be adapted to any distribution of mass or thrust.

In embodiments, at least one wing root support is set in motion by a motor, a central unit actuating said motor. Thanks to these provisions, the center of canopy thrust can be moved back and forth on the hydrofoil body, independent of canopy geometry dictated by the distance between the wing root supports.

In embodiments, at least one wing root support includes a rail and a worm. Thanks to these provisions, the movement of the wing root support is easy.

In embodiments, at least one front wing root support comprises at least one pivot.

In some embodiments, a rod internal to one of the wings maintains the main plane of the vertical surface of closure of the ends of the wings parallel to the main axis of the body of the hydrofoil.

Thanks to these provisions, the junctions of the front and rear wings can be simplified since they do not have the function of maintaining the plane of the vertical closing surfaces of the wing tips in position.

In embodiments, the front and rear wing tip junctions include pivots.

In embodiments, the rear fenders have a spoiler profile. These provisions correspond to the cases of boats in which the mast of the hydrofoil is behind the boat, therefore its center of gravity, for example sailboards or surfboards.

In embodiments, the rear wings have a carrier profile. These provisions correspond to the cases of boats in which the mast of the hydrofoil is under the center of gravity of the boat, for example for monohull or multihull sailboats.

According to a second aspect, the present invention relates to a boat comprising a hydrofoil which is the subject of the invention.

The advantages, aims and characteristics of this craft being similar to those of the hydrofoil which is the subject of the invention, they are not repeated here.

In some embodiments, the boat that is the subject of the invention comprises means for adapting the position of at least one wing root to the navigation conditions.

Thanks to these provisions, during navigation, depending on the on-board load, the speed, the depth of the hydrofoil in relation to the surface of the water, the target autonomy and/or the maneuverability targeted, the adaptation means modifies the geometric configuration of the airfoil by moving at least one wing root.

In some embodiments, the boat which is the subject of the invention comprises means for morphing the wings, to modify the inclination of the axes of rotation of the wings and cause a variation in incidence, the adaptation means controlling the means of morphism.

Thanks to these provisions, during navigation, depending on the on-board load, the speed, the depth of the hydrofoil in relation to the surface of the water, the target autonomy and/or the maneuverability targeted, the means of adaptation modifies the incidence of the airfoil.

BRIEF DESCRIPTION OF FIGURES Other advantages, objects and characteristics of the present invention will emerge from the description which will follow given, for an explanatory and in no way limiting purpose, with regard to the appended drawings, in which:

- Figure 1 shows, schematically and in perspective view, a first particular embodiment of the boat object of the invention,

- Figure 2 shows a detail view of Figure 1,

- Figure 3 shows, schematically and in side view, the boat illustrated in Figures 1 and

2,

- Figure 4 shows, schematically and in front view, the boat illustrated in Figures 1 to

3,

- Figure 5 shows, schematically and in top view, a first particular embodiment of the hydrofoil object of the invention,

- figure 6 represents, schematically and in side view, the hydrofoil illustrated in figure 5,

- Figure 7 shows, schematically and in top view, a second particular embodiment of the hydrofoil object of the invention, in a first configuration,

- Figure 8 shows, schematically and in top view, the hydrofoil illustrated in Figure 7, in a second configuration,

- Figure 9 shows, schematically and in top view, the hydrofoil illustrated in Figures 7 and 8, in a third configuration,

- figure 10 represents, schematically and in perspective, the hydrofoil illustrated in figures 7 to 9, in the configuration illustrated in figure 8,

- Figure 11 shows, schematically and in perspective, a movable front wing root support joint,

- Figure 12 shows, schematically and in perspective, a movable rear wing root support joint,

- Figure 13 shows, schematically and in perspective, a front and rear wing tip articulation,

- figure 14 represents, in the form of a flowchart, the operating steps of the hydrofoil illustrated in figures 7 to 13,

- Figure 15 shows, schematically and in perspective view, a second particular embodiment of the boat object of the invention,

- figure 16 shows, in side view, the boat illustrated in figure 15,

- Figure 17 shows, in front view, the boat illustrated in Figures 15 and 16, and

- Figure 18 shows, in front view, the boat illustrated in Figures 15 to 17.

DESCRIPTION OF EMBODIMENTS

Note, from now on, that the figures are not to scale. To simplify the understanding of the drawings and diagrams, the wings and vertical surfaces at the junction of the ends of the wings are represented by thin surfaces. Throughout the description, the directions are oriented according to the flow of water intended to pass through the hydrofoil. When this hydrofoil is mounted on a boat, these directions thus correspond to those of the boat. We therefore call "front" what is directed towards the arrival of the flow of water during navigation, "rear" what is directed towards the distance from the water during navigation, "lower", what is distant from the surface of the water and therefore from the float of the boat, "upper" which is closer to the surface of the water and therefore from the float of the boat and "lateral" which is far from the plane of symmetry of the hydrofoil and the plane of symmetry of the craft. "Lateral" thus corresponds to the sides of the boat, also called port and starboard.

We recall the following definitions: a boat is a "small boat, generally undecked, sailing, rowing, steam or motor", the term "boat" could be replaced by "nautical boat" a hydrofoil is “In fluid mechanics, a hydrofoil is a wing positioned and profiled in such a way as to generate, by its displacement in the water, a lift force which acts on its speed and its stability. », a rhombohedron is a three-dimensional polyhedron resembling a cube, except that its faces are not square but in the shape of diamonds. By extension, according to the present invention, the four wings have diamond shapes but the front and rear faces of this rhombohedron may not be flat and have two lower sides, respectively the leading and trailing edges of the lower wings, of which the length is different from that of their two upper sides, respectively the leading and trailing edges of the upper wings.

A daggerboard is used to ensure the lateral stability of a boat, while a hydrofoil aims to lift or “take off” a boat from an aquatic environment.

FIGS. 1 to 4 show a boat 40 comprising a hydrofoil 20 connected to a hull 41 by a lower mast 45. The hull 41 also carries a mast 42, two sails 43 and 44 being supported by the mast 42. , in FIG. 3, an axis 47 of movement of the boat 40 and a main axis 46 of the hydrofoil 20 parallel to the axis 47.

The boat 40 moves at least partially in the aerial environment and on an aquatic environment, the hydrofoil being immersed in the aquatic environment. The purpose of a hydrofoil is to lift the boat, at least partially, i.e. to reduce the contact surface between the boat and the aquatic environment. Although the boat 40 takes, in the figures, the form of a sailing monohull, the hydrofoil object of the invention applies equally well to any boat including, in particular, windsurfing boards, surfboards surfing and boats with one or more hulls, sailing and/or motor. The boat that is the subject of the invention may comprise one or more rhombohedral hydrofoils.

The watercraft hydrofoil 40 moving parallel to a horizontal axis 46 is symmetrical with respect to a vertical plane and rhombohedral or rhomboidal or rhomboidal. The rhombohedron is defined with respect to this vertical plane and this horizontal axis. We recall that a sail rhombohedral (or rhomboidal or rhomboid) is a variant of tandem wings whose ends meet. The front wing fixed to the lower part of the body of the hydrofoil is swept back, and the rear wing fixed to the upper part of the fin is swept forward. The wing, made up of all the wings, forms a continuous quadrilateral projected surface, close to a diamond, hollow.

The hydrofoil 20 is intended to be mounted on a lower mast 45 (see FIGS. 1 to 4) of a predetermined boat 40. In other words, the geometric configuration of the hydrofoil 20 depends on the physical characteristics, in particular weight and position of the mast 45, of the boat 40. The hydrofoil 20 comprises lower front wings 21 and 22 connected together by a junction, or wing root, 23 and 24, and upper rear wings 25 and 26 connected between them by a junction or wing root 31 . This means that the front wings 21 and 22 are, once the hydrofoil mounted on the lower mast of the boat, further from the boat than the rear wings 25 and 26.

The end of each front wing, furthest from the junction of the front wings, is connected to an end of a rear wing, the furthest from the junction of the rear wings, by a mechanical connection, respectively 27 and 28. front wings 21 and 22 have a carrying profile, that is to say their forward movement in the water generates lift tending to bring the hydrofoil 20 closer to the surface of the water and to lift the mast connecting the hydrofoil to the boat. The rear wings 25 and 26 have, in the case of a hydrofoil positioned on a mast 45 under the center of gravity of the boat 40, a carrier profile.

All of these wings 21, 22, 25 and 26 have a first orthogonal projection on a so-called "vertical" plane perpendicular to the axis of movement 46. The first projection has the shape of a quadrilateral having an obtuse angle at from the junction of the front wings, an obtuse angle at the junction of the rear wings and two acute angles at the junction of a front wing and a rear wing.

All of these wings 21, 22, 25 and 26 have a second orthogonal projection on a so-called "horizontal" plane orthogonal to the plane of symmetry and comprising an axis parallel to the axis of displacement 46. The second projection has the shape of a a quadrilateral having only angles of measure less than 180 degrees.

In the first embodiment illustrated in FIGS. 5 and 6, the hydrofoil 20 comprises a body 32. In other embodiments, the hydrofoil which is the subject of the invention does not comprise a body, the wings being interconnected to form a rhombohedron, a figure of which two orthogonal projections on orthogonal planes (here a vertical plane perpendicular to the axis 46 and a horizontal plane), form quadrilaterals whose measures of all the angles are less than 180 degrees. The front 21 and 22 and rear 25 and 26 wing root supports 23, 24 and 31 are positioned respectively on either side of this body 32 in the vertical plane of symmetry of the hydrofoil 20. The body 32 thus ensures the rigidity of the hydrofoil 20 and makes it possible to reduce the thicknesses of the wings 21, 22, 25 and 26. More precisely, the connection of the front wings 21 and 22 is in the lower part of the body 32 and the connection of the rear wings 25 and 26 is in the upper part of body 32. The hydrofoil 20 comprises, at least on each wing of a pair of wings (here the rear wings 25 and 26), at least one flap, respectively 29 and 30, actuated by an actuator (not shown). An active stabilization system of the boat 40 is thus particularly effective. In some embodiments, the front wings 21 and 22 thus have control surfaces (not shown), ailerons or flaps and the rear wings 25 and 26 have control surfaces (not shown), ailerons or flaps.

At each junction of the front 21 and 22 and rear 25 and 26 wing ends is positioned a vertical surface, respectively 27 and 28, one axis of which is parallel to the axis 46. These vertical surfaces 27 and 27 closing the ends of wings reduce the drag of the airfoil. The closure of the ends of the wings, to obtain an almost infinite elongation wing, thus consists of a vertical hydrodynamic surface 27 or 28 (profiled or not). One of the characteristics of rhomboid wings is the absence of a vertical surface, therefore a significant gain in profile drag. Each vertical surface 27 or 28 which joins two wings at their ends makes it possible to close the space and thus, in theory, to have a wing close to an infinite-span wing.

In embodiments, the body 32 of the hydrofoil 20 includes a ballast. The hydrofoil thus has a dual function. In embodiments, the body 32 of the hydrofoil 20 includes ballast. The ballast can thus be emptied when the hull of the boat 40 rises out of the water. Each of the wings 21, 22, 25 and 26 shown in the figures has a generally rectangular shape. They are thus of constant chord, their leading and trailing edges being parallel. Of course, the present invention is not limited to this type of general shape but extends to all shapes of wings, except delta wings.

The inventor discovered that the rhomboid configuration makes it possible to maintain an almost constant glide ratio over a wide speed range by varying the camber of the front wings (and rear to maintain a balanced flight). This feature has been confirmed in wind tunnel studies. The use of wing morphism is particularly well suited because a small angular variation of the front and rear wings can introduce significant variations in incidence and/or variation in camber over their wingspan. This makes it possible to limit the use of flap deflections, which have the disadvantage of the complexity of the mixing of the eight flaps and the lack of precision/resolution of the servomotors and the mechanical controls of these servomotors.

The morphism is an extremely elegant solution to "fine-tune" the adjustment of the wing to the flight conditions without having the inconvenience of heavy and hydrodynamically unclean solutions of multiple flaps at the trailing edge and/or slats and other appendages at the trailing edge. 'offensive. The rhomboid type blade lends itself particularly well to this type of “control”.

In FIG. 7, a hydrofoil 50 is observed comprising a body 51 of the hydrofoil and a wing 52 of rhombohedral shape. The hydrofoil 50 is intended to be mounted on a lower mast of a predetermined craft. In other words, the geometric configuration of the hydrofoil 50 depends on the physical characteristics, in particular weight and position of the mast, of the boat. The hydrofoil 50 comprises a lower left front wing 53, a lower right front wing 54, an upper left rear wing 55 and an upper right rear wing 56. This means that the front wings 53 and 54 are, once the hydrofoil mounted on the lower mast of the boat, farther from the boat than the wings rear 55 and 56.

The front wings 53 and 54 meet on a front wing root support 57 located below the body of the hydrofoil 51 . The rear wings 55 and 56 meet on a rear wing root support 58. The left wings 53 and 55 meet at a left wing junction 59 located above the body of the hydrofoil 51 . The right wings 54 and 56 meet on a right wing junction 60. The front wings 53 and 54 have control surfaces 63 to 66, ailerons or flaps. The rear wings 55 and 56 have control surfaces 73 to 76, ailerons or flaps. The front wings 53 and 54 have a carrying profile when the control surfaces 63 to 66 are in a neutral position, that is to say that their forward movement in the water generates lift tending to bring the hydrofoil closer. from the surface of the water and to lift the mas connecting the hydrofoil to the boat. The left wingtip junction 59 is hinged, allowing relative angular movement of the left front wing 53 relative to the left rear wing 55. Similarly, the right wingtip junction 60 is hinged. , which allows a relative angular movement of the right front wing 54 with respect to the right rear wing 56.

At least one of the wing root supports 57 and 58 is movable along the body of the hydrofoil 51, which allows a deformation of the rhombohedral wing 52, a variation of the deflection of each wing and therefore of the wingspan of the airfoil 52. Thanks to these variations, the airfoil 52 can be adapted to different speed ranges. In Figure 8, we see the hydrofoil 50, in a sail configuration with a reduced sag angle and an extended wingspan. In figure 9, we see the hydrofoil 50 in a configuration of wings with superimposed wings, a large angle of sag and a reduced wingspan.

As seen in Figures 7 to 9, especially Figure 8, in the embodiment shown there, the length 81 of the rear wings 55 and 56 is strictly less than the length 88 of the front wings 53 and 54. the angle 82 formed between the main longitudinal axis 84 of the body of the hydrofoil 51 and the main axis 83 of the rear wings is, consequently, in all flight configurations, more obtuse than the angle 86 formed between the axis main longitudinal of the body of the hydrofoil and the main axis 85 of the front wings. Note that the length of the wings is the largest dimension of the wings measured parallel to their main axis.

Thus, the front wings 53 and 54 are always in the arrow configuration and the rear wings 55 and 56 can assume an inverted arrow configuration (FIG. 7), straight (intermediate between the configurations represented in FIGS. 8 and 9), that is that is to say perpendicular to the body of the hydrofoil, or in non-inverted arrow (figure 9), as well as in all the intermediate configurations. In other embodiments, the length of the rear fenders is equal to or greater than the length of the front fenders.

In the embodiment illustrated in Figures 7-9, at least one of the wing root supports 57 and 58 (both wing root supports, in Figures 7-9) is configured to approximate the other wing root support so that the front wings 53 and 54 form the hypotenuses of right-angled triangles formed by the front wings, the rear wings 55 and 56 and the body of the hydrofoil 51 . The main axis 83 of each of the rear wings is, in these right-angled triangles, perpendicular to the main longitudinal axis 84 of the body of the hydrofoil.

As seen in Figure 9, at least one of the wing root supports 57 and 58 (both wing root supports, in Figures 7-9) is configured to approach the other wing root support so that the front wings 53 and 54 and the rear wings 55 and 56 are in arrows, not inverted. Thus, the deflection of the front wings 53 and 54 can be increased and the wingspan 89 reduced, in particular for configurations of use at higher speeds.

As seen in Figures 8 and 9, at least one of the wing root supports 57 and 58 (both wing root supports, in Figures 7 through 9) is configured to move away from the other wing root support so that the wingspan 89 (shown in Figure 9) of the hydrofoil 50 is less than the sum of four times the maximum width 87 (shown in Figure 8) of the front wings 53 and 54 and the rear wings 55 and 56, on the one hand, and the width 90 of the body of the hydrofoil 51, on the other hand. It is noted that the width 87 of the wings is the largest dimension of the wings measured perpendicular to their main axis 83 or 85. In the embodiment represented in FIGS. 7 to 9, the maximum width 87 of the front and rear wings is on the front wings 53 and 54. As illustrated in FIG. 10, the wing root supports are preferably positioned respectively below and above the body of the hydrofoil 51, this configuration being optimal for several aspects.

Preferably, as illustrated in Figures 7 to 13, each of the wing root supports 57 and 58 is movable along the body of the hydrofoil. To this end, each wing root support, respectively 57 and 58, is moved on a rail, respectively 67 and 68, by an electric motor, respectively 69 and 71, provided with an endless screw, respectively 70 and 72. An electronic control unit 77 (see FIG. 9) comprises a central unit which actuates the motors 69 and 71 in a coordinated fashion. The electronic control box 77 also provides control functions for the control surfaces 63 to 66 and 73 to 76. In addition, the electronic control box 77 constitutes a means of adapting the position of each wing root to the speeds displacement, for example the on-board load, the speed, the altitude, the target autonomy, the target manoeuvrability. The adaptation means 77 modifies the geometric configuration of the airfoil by moving at least one wing root.

In variants, the hydrofoil 50 comprises wing morphism means, to modify the inclination of the axes of rotation of the wings and cause a variation in incidence, the adaptation means controlling the morphism means. Preferably, in these variants, the electronic box modifies the incidence of the wing during the movement of the boat, depending on the on-board load, the speed, the altitude, the target autonomy, the maneuverability aimed.

As illustrated in the right part of Figure 8 and in Figure 13, at each junction 59 and 60 of the front and rear wing tips is positioned a vertical surface for closing the wing tips 78. A rod 79 internal to one wings, a front wing in figures 7 to 13, maintains the principal plane of the vertical wingtip closing surface 78 parallel to the principal axis of the body of the hydrofoil 51 .

As illustrated in FIG. 13, the junctions 59 and 60 of the ends of the front and rear wings comprise pivots. To give a third degree of freedom, over a few degrees of angle, this pivot connection has flexibility or a ball joint.

As illustrated in Figures 1 1 and 12, at least one (and preferably both) wing root support 57 and 58 comprises pivots and a base 80 moved along the body of the hydrofoil 51 by the engine, respectively 69 and 71 .

Described below, with reference to Figure 9, a mode of operation of the hydrofoil 50. The front and rear wings are articulated at the root at their point of embedding with the body of the hydrofoil and the wings right front and rear as well as the left front and rear fenders are hinged together at their ends (marginal edges).

This root and/or tip articulation point may or may not be located in the hydrodynamic loft of the wing. The hydrodynamic loft is the 3D surface of the hydrofoil which is used for studies, modeling and simulations. This 3D model can also be used to make the model for wind tunnel testing. It is the "perfect" hydrodynamic version of the hydrofoil which will then be adapted to the constraints of production, use, maintenance, regulations, etc... It is therefore imperative to respect this shape/surface as well as possible in order to have a device also whose performance is as close as possible to the initial “theoretical” design. The root joints with the body of the hydrofoil can move fore and aft and independently in order to obtain the desired geometry while respecting the constraints on the position of the center of gravity required by the transitional form plan and/or desired.

These root joints, while moving longitudinally, can also move up and/or down in order, for example, to obtain the appropriate angle of attack according to the deflection of the wing. The incidence of the wings is changed according to the configuration of the wing so that the profiles of the wings (section parallel to the flow) are always in values adapted to this configuration. The variations in the angle of incidence are, in general, of low (even very low) amplitude. It is by the inclination of the axes of rotation of the wings that this variation in incidence takes place. The influence of this inclination on the dihedral (positive or negative) is also taken into account. On the model illustrated in Figures 7 to 13, the variations in incidence are of the order of 0.5 degrees of angle over a range of variations in incidence extending up to five degrees of angle.

The inclination of the axes of rotation of the wings at their embedding at the root can introduce or eliminate angular variations in incidence. If this axis is perpendicular to the plane of the wing, the dihedral will naturally generate an angular variation of the chord of the wing with respect to the frame of reference for the flow of air (the chord of a wing being the corresponding section to the wing section by a vertical plane perpendicular to the plane of the wing and parallel to the flow/longitudinal “X” axis of the hydrofoil). It must be ensured, in the case of a change in incidence introduced by the inclinations of the axes of rotation, that the variations are in phase between the front wings and rear to minimize any stresses at the ends that may be introduced by the geometry and the choice of the degrees of freedom at the level of the mechanism linking the ends of the front and rear wings together.

In some embodiments, the hydrofoil 50 comprises means for morphing the wing, to modify the inclination of the axes of rotation of the wings and cause a variation in incidence. In these embodiments, a torsion moment is imposed on the roots of the wings, via their articulation/embedding, and thus produce a phenomenon of morphism by the use, for example, of composite materials and/or a structure adapted internal of the wing. The morphism aims to have a structure with the skin that deforms to replace or complete the controls (ailerons, flaps, etc.) and thus minimize drag (in profile and induced). On a cantilever wing, there is an internal reformable structure which produces the deformation at the level of the skin (of the loft) necessary to obtain the modification of performance (drag, lift) desired/necessary. Another solution is to deform the skins using electromagnetic currents.

In the case of the rhombohedral wing, due to the “rigid” structure due to the bracing on the three axes, it is possible to introduce quite easily (such as for the change in incidence) stresses in the ends of the wings. In some embodiments, a wing is provided whose structure “twists” to increase (or decrease) its incidence at the root and/or at the tip. This makes it possible to modify the lift of this wing and thus to replace the flaps. These variants are, for example, used to modify the characteristics of the wing according to the speed of movement of the boat 40.

As detailed above, the inclination of the axes of rotation around the wing embedding points at the roots/ends as well as the control and arrangement of the degrees of freedom at the embeddings can introduce constraints either in the longitudinal direction (span) either in the transverse direction (chord) and thus introduce torsional stresses which, for example by adjusting the angles of the axes of rotation and with a suitable structure, allow constant or changing twisting over the span of the wing. It can even be introduced a "buckling" of the wing on its wingspan, if deemed necessary.

It is also possible to impose on the ends of the wings via their articulation a moment of torsion and thus introduce a phenomenon of morphism by the use (for example) of composite materials and/or an internal structure adapted from the wing. Rigid, semi-rigid and/or flexible fairings can enclose the various joints to ensure good hydrodynamic sealing and/or clean hydrodynamic flow. In some embodiments, the body 51 of the hydrofoil 50 includes a ballast. In some embodiments, the body 51 of the hydrofoil 50 comprises a ballast operating as described with regard to the first embodiment illustrated in FIGS. 5 and 6.

In FIG. 14, the operating steps of the hydrofoil illustrated in FIGS. 7 to 13 are observed. During a step 91, the desired flight altitude of the boat 40 is determined, according to the flight controls of the browser or provided by flight optimization software. During step 92, the conditions of the corresponding flight envelope are determined, taking into account flight conditions (speed, wind, on-board weight, remaining range, etc.). During a step 93, the configuration (angles of the dihedral and angle of incidence) of the airfoil is determined for this area of flight and/or this desired speed (according to objectives of stability, reduced consumption, maneuverability, ...). For example, starting from the knowledge for certain geometric configurations of the airfoil, including the extreme configurations (FIGS. 7 and 9), this knowledge is interpolated for all the other configurations.

During a step 94, the displacements of the two wing roots are calculated to bring the center of thrust to the desired location and the displacements of the morphism means ensuring a variation in the angle of incidence. During a step 95, the stepper motors and the servomotors are controlled, in a coordinated and simultaneous manner, so that the geometric configuration of the airfoil is achieved.

In its second embodiment illustrated in FIGS. 15 to 18, the boat 100 takes the form of a surfboard which comprises a float 101 and a lower mast 105 supporting a hydrofoil 20. Of course, the hydrofoil 20 of the second embodiment of the boat has smaller dimensions than that of the first embodiment of the invention. The rear wings of the Hydrofoil 20 configured for a surfboard or a sailboard have a spoiler profile.

Claims

1 . Rhombohedral hydrofoil (20, 50) for mounting on a lower mast (45, 105) of a boat (40) moving in a direction parallel to an axis (46), this hydrofoil having a plane of symmetry and comprising, in this direction, front wings further away from the boat (21, 22, 53, 54) connected to each other and rear wings closer to the boat (25, 26, 55, 56) connected to each other, characterized in that :

- the end of each front wing, furthest from the junction of the front wings, being connected to one end of a rear wing, the farthest from the junction of the rear wings,

- the set (52) of these wings having a first orthogonal projection on a so-called "vertical" plane perpendicular to the axis of displacement, projection having the shape of a quadrilateral having an obtuse angle at the level of the junction of the front wings , an obtuse angle at the junction of the rear wings and two acute angles at the junction of a front wing and a rear wing;

- all of these wings having a second orthogonal projection on a so-called "horizontal" plane orthogonal to the plane of symmetry and comprising an axis parallel to the axis of displacement, projection having the shape of a quadrilateral having only angles of measurements less than 180 degrees; And

- the front fenders have a supporting profile.

2. Hydrofoil (20, 50) according to claim 1, which further comprises a body (32, 51) comprising:

- a clip for the lower mast (45, 105) of the boat,

- a support (23, 24, 57) for the root and junction of the front wings (21, 22, 53, 54) and

- a support (31, 58) for the root and junction of the rear wings (25, 26, 55, 56), the front and rear wing root supports being positioned respectively, on either side of this body in the plane of symmetry of the hydrofoil.

3. Hydrofoil (20, 50) according to claim 2, wherein the body (32, 51) of the hydrofoil comprises a ballast.

4. Hydrofoil (20, 50) according to one of claims 2 or 3, wherein the body (32, 51) of the hydrofoil comprises a ballast.

5. Hydrofoil (20, 50) according to one of claims 1 to 4, which comprises, at least on each wing (25, 26, 53, 54, 55, 56) of a pair of wings, at least one flap (29, 30, 63 to 66, 73 to 76) actuated by an actuator.

6. Hydrofoil (20, 50) according to one of claims 1 to 5, in which, at each junction of the ends of the front and rear wings, a vertical surface (27, 28, 78) for closing these ends is positioned. wings.

7. Hydrofoil (50) according to one of claims 1 to 6, wherein the rear wings have a spoiler profile.

8. Hydrofoil (20) according to one of claims 1 to 6, wherein the rear wings have a carrier profile.

9. Hydrofoil (50) according to one of Claims 2 to 4 or one of Claims 5 to 8 when dependent on Claim 2, in which:

- one end of each front wing (53, 54) is hinged to one end of a rear wing (55, 56) and

- at least one of the wing root supports (57, 58) is movable along the body of the hydrofoil.

10. Hydrofoil (50) according to claim 9, in which the length of the rear wings is strictly less than the length of the front wings, the angle formed between the main longitudinal axis of the body of the hydrofoil and the main axis of the rear wings being consequently more obtuse than the angle formed between the main longitudinal axis of the body of the hydrofoil and the main axis of the front wings.

11 . Hydrofoil (50) according to one of Claims 9 or 10, in which at least one of the wing root supports is configured to approach the other wing root support so that the front wings form the hypotenuses of right-angled triangles formed by the front wings, the rear wings and the body of the hydrofoil, the main axis of each of the rear wings being, in these right-angled triangles, perpendicular to the main longitudinal axis of the body of the hydrofoil .

12. Hydrofoil (50) according to one of claims 9 to 1 1, wherein at least one of the wing root supports is configured to approach the other wing root support so that the wings front and rear fenders are swept back, not inverted. Thanks to these provisions, the deflection of the front wings can be increased and the wingspan reduced, in particular for flight configurations at higher speeds.

13. Hydrofoil (50) according to one of claims 9 to 12, wherein at least one of the wing root supports is configured to move away from the other wing root support so that the wingspan of the hydrofoil is less than the sum of four times the maximum width of the front wings and the rear wings, on the one hand, and the width of the body of the hydrofoil, on the other hand.

14. Hydrofoil (50) according to one of claims 9 to 13, in which each of the wing root supports is movable along the body of the hydrofoil. Thanks to these provisions, the geometric configuration of the airfoil can be adapted to any distribution of mass or thrust.

15. Hydrofoil (50) according to one of claims 9 to 14, wherein at least one wing root support is set in motion by a motor, a central unit actuating said motor. Thanks to these arrangements, the center of thrust of the airfoil can be moved fore and aft on the body of the hydrofoil, independent of the geometry of the airfoil dictated by the distance between the wing root supports.

16. Hydrofoil (50) according to one of claims 9 to 15, wherein at least one front wing root support comprises at least one pivot.

17. Hydrofoil (50) according to one of Claims 9 to 16, in which an internal rod in one of the wings maintains the main plane of the vertical closing surface of the ends of the wings parallel to the main axis of the body. hydrofoil.

18. Hydrofoil (50) according to one of claims 9 to 17, wherein the junctions of the ends of the front and rear wings comprise pivots.

19. Boat (40, 100) comprising a hydrofoil (20, 50) according to one of claims 1 to 18. 16

20. Craft (40, 100) according to claim 10, in which the hydrofoil (50) is according to one of claims 9 to 18 and comprises means (51) for adapting the position of at least one root (57, 58) of wings to navigation conditions.

21 . Boat (40, 100) according to one of claims 10 or 1 1, which comprises means for morphing the wings, to modify the inclination of the axes of rotation of the wings and cause a variation in incidence, a means of adaptation (51) controlling the morphism means.