Foil Assembly Comprising a Hollow T-Shaped Connector

The present application is a National Stage Application of PCT International Application No. PCT/IB2023/056922 (filed on Jul. 4, 2023), under 35 U.S.C. § 371, which claims priority to French Patent Application No. FR 2206801 (filed on Jul. 5, 2022), which are each hereby incorporated by reference in their complete respective entireties.

The present invention falls within the field of naval design, it relates more particularly to a foil assembly for a hydrofoil which comprises a hollow T-shaped connection piece, ensuring the connection between the foil and the mast.

The prior art knows hydrofoils with foils. A hydrofoil is a boat capable of planing, that is, of rising out of the water and maintaining its balance out of the water under the effect of speed, by means of several lifting surfaces placed under its hull.

Such a carrier plane is most commonly referred to by the term “foil”. The foil can also be called a “wing,” “lifting wing,” “sustaining plane,” or even be designated by the English term “hydrofoil.” The foil is supported by a generally straight structural element, the so-called “mast,” that extends under the hull. The term “foil assembly” refers to the assembly formed by a mast and a foil.

To meet manufacturing constraints, the mast and the foil of a foil assembly are usually manufactured separately and then connected to each other by suitable fixing means such as glue and/or screws and nuts. Being understood that the mechanical constraints are particularly strong at the junction between the mast and the foil, it is known to provide a junction piece in the shape of an inverted “T” whose horizontal part is made integral with the foil and whose vertical part is made integral with the mast. This junction or connection piece can be added or be an integral part of the foil or the mast. To facilitate the design, production and transportation of the T-junction piece, it is often added. The dimensions and material constituting the “T” shaped junction piece are chosen according to the structural constraints anticipated for the foil assembly, at the junction between the mast and the wing.

In addition, the foil assembly usually includes force transfer means, in particular for controlling a fin, data transmission means and/or means for transporting liquid, in particular for allowing the cooling of a hydrofoil motorization system. These means can be fixed on the perimeter of the mast but in this case have an impact negative on the hydrodynamic performance of the foil assembly. To limit this negative impact, it is known to fix said means on the trailing edge of the mast.

There is a need to improve the integration of elements useful for the operation of the hydrofoil into the foil assembly while maintaining the robustness of the foil assembly compatible with navigation in flight out of the water, carried by the hydrofoil foils.

The present invention aims to meet the need described above. To do this and according to a first aspect, the invention aims at a foil assembly for a hydrofoil which comprises: a mast comprising a first longitudinal through cavity, a foil, and a T-shaped connector comprising a first part which includes means of attachment to the foil and a second part which includes means of attachment to the mast, and in which the T-shaped connector is pierced with a second cavity, opening onto the first cavity, so that the first and second cavities together form a chamber for housing elements useful for the operation of the hydrofoil.

Thanks to these provisions, elements useful for the operation of the hydrofoil are housed in the foil assembly. This positioning of said elements inside the foil assembly improves the hydrodynamic performance of the foil assembly compared to external positioning (for example on the trailing edge of the mast). Furthermore, these provisions prevent the risk of said elements being damaged by contact with water when the hydrofoil is moving.

For the purposes of this application, the term “T-shaped connector” means a junction piece comprising two parts, one of which is configured to be mounted integrally with the foil and the other configured to be mounted integrally with the mast. It should be noted that the angle formed between these two parts is not necessarily a right angle, although this is preferentially the case according to at least one point of view on the T-shaped connector (in front view or in side view).

In embodiments, the mast is a hollow body comprising a plurality of spars, i.e., longitudinal walls, separating the hollow body into several through cavities called “chambers,” one of which forms the first longitudinal through cavity of the mast.

For example, the mast has two spars delimiting, with the perimeter of the mast, three chambers including a central chamber and two lateral chambers, less voluminous than the central chamber. Advantageously, said side members ensure a transfer of mechanical forces.

In embodiments, the surface area of the chamber along any transverse section plane of the mast is greater than or equal to 3000 mm2, preferably greater than 3500 mm2, preferably greater than 4000 mm2, very preferably greater than 4500 mm2 or 4800 mm2. In embodiments, the surface area of the chamber is greater than or equal to 30% of the total surface area occupied by the mast on any transverse section plane of the mast, preferably greater than 40%, very preferably greater than 45%. Thanks to these arrangements, a large chamber is provided along the entire length of the mast and through the T-shaped connector.

The cross-sectional plane of the mast is a sectional plane perpendicular to the central longitudinal axis of the mast.

According to the invention, the first and second cavities together form a chamber for housing elements useful for the operation of the hydrofoil. In other words, the first and second cavities open onto each other and provide communication between the foil and the mast, preferably up to the top of the mast. These arrangements allow systems to be positioned partially in one of the two cavities and partially in the other cavity. In addition, the void thus created through the foil assembly can extend to the hydrofoil cabin or to the internal structure of the hydrofoil, allowing for example the transfer of force, the actuation of mechanical systems, the transmission of electrical signals or even the transport of fluids from the foil to the rest of the hydrofoil.

Elements useful for the operation of the hydrofoil are understood to mean any means enabling the operation of a system positioned on the foil assembly and in particular the systems connected to the hydrofoil. In particular, the elements useful for the operation of the hydrofoil may include means chosen from: means of force transfer, means of electrical signal transmission, and means of fluid transport.

The means for transferring forces and actuating mechanical systems comprise, for example, a connecting rod, as described in the present application, or a rod, a pulley, or even a transmission belt. These means are particularly useful for controlling one or more ailerons positioned on the wing. Hydraulic or pneumatic systems can also be included among these means of force transfer.

Electrical signal transmission means include any cable or fiber that allows the transfer of a command or data, such as sonar or communication data, in the form of an electrical signal. The transmitted signals can be ascending, for example when data is measured by a sensor and then transmitted to a computer system positioned outside the wing on the hydrofoil. The transmitted signals can be descending, for example in the case of a control signal which would be transmitted to a system located in the foil assembly.

Preferably, the chamber formed by said first cavity and second cavity is through, that is to say that it comprises at least two openings, at two ends of the foil assembly. Preferably, a first opening of the chamber is located at the level of the mast head, for example so as to open onto the internal structure of the hydrofoil. Preferably, a second opening is located at the foot of the mast, for example so as to open into the internal structure of the foil or outside the foil assembly.

“Mast foot” means a part of the mast at the end of the mast attached to the foil, for example the mast foot corresponds to one fifth of the total height of the mast closest to the foil. The term “mast head” means the opposite part, for example the mast head corresponds to the fifth of the total height of the mast furthest from the foil.

In embodiments, the elements useful for operating the hydrofoil include a device for controlling the tilt of a fin provided with a lever.

In embodiments, said lever is at least partially housed in the chamber.

Thanks to these arrangements, the lever arm is larger compared to the lever arm of a lever that would be positioned on the trailing edge of the mast. The control of the aileron is thus improved and/or requires a lower power motor for its operation.

According to the prior art, the lever arm is usually behind the wing pivot axis resulting in a low lever arm.

On the contrary, according to a preferred embodiment of the invention, the lever is positioned in front of the pivot axis of the fin. So the lever arm of the lever is in front of the wing pivot axis. This results in a working mode of the connecting rod connected to the lever arm mainly in traction during the aileron deflections downward since the force is in front of the pivot point. These provisions make it possible to limit the weight of the connecting rod.

It is emphasized that the provision of a hollow T-shaped connector according to the invention facilitates, in view of the space freed up to accommodate the connecting rod and possibly part of the lever, the installation of a lever arm positioned in front of the pivot axis of the fin.

In embodiments, the length of the lever arm of the lever is greater than or equal to 120 millimeters (mm), preferably greater than 150 mm, preferably greater than 180 mm. In embodiments, the lever arm length of the lever is between 50% and 100% of the aileron chord. The aileron chord is the distance between the leading edge and the trailing edge of the aileron profile.

In embodiments, the device for controlling the tilt of said aileron comprises a connecting rod housed at least partly in the first cavity, said connecting rod being connected at its lower end to the lever and its upper end to a means ensuring a translational movement along a substantially vertical axis.

In the present application, the term “lower end” of the connecting rod refers to its end closest to the water during normal operation of the hydrofoil and the term “upper end” of the connecting rod refers to its end furthest from the water, for example placed at the top of the mast.

Thanks to these provisions, the systems providing the motorization of the tilt control device can be offset, for example at the mast head.

In embodiments, the means providing translational movement along a substantially vertical axis comprises a carriage movable on a rail moved by means of a ball screw.

Thanks to these provisions, the carriage constrains the movement in vertical translation and the ball screw allows precise control of the movement of the connecting rod and consequently precise control of the tilt of said fin.

In embodiments, the means ensuring a translational movement along a substantially vertical axis comprises a driven pulley, configured to drive the ball screw, connected via a transmission belt to a driving pulley set in rotation by a motor.

Thanks to these arrangements, the motor can be offset from the ball screw, which reduces the space requirement at the mast head in comparison of a motor which would be placed directly above the pulley configured to drive the ball screw. In addition, the use of several pulleys, for example a first pulley, integral with the motor shaft, and a second pulley, cooperating with the ball screw, allows fine control of the power ratio between the motor and the ball screw.

In embodiments, the first portion of the T-shaped connector is mounted in a recess on the foil such that the surface of the foil and the visible surface of the first portion of the T-shaped connector form a smooth assembly.

In other words, a shallow cavity, of height substantially equal to the height of the first part of the T-shaped connector and of width and length substantially equal to the width and length of the first part of the T-shaped connector, is provided in the extrados of the foil. These provisions make it possible to avoid the presence of a shoulder at the interface between the first part of the T-shaped connector and the foil. The hydrodynamic performance of the foil is thus preserved.

It should be remembered that the extrados of a foil is the cambered face of the foil, oriented towards the surface during normal use of a hydrofoil, and which provides lift. On the contrary, the intrados is the face opposite the camber, oriented towards the seabed during normal use of the hydrofoil.

In embodiments, the T-shaped connector is a monolithic piece of titanium. For the purposes of this application, a monolithic part is understood to mean a part formed from a single piece. Titanium has advantageous mechanical resistance for a relatively light weight, allowing the weight of the hydrofoil to be reduced. The implementation of a monolithic part makes it possible to limit the use of connecting means between parts, which reduces the complexity of the T-shaped connector and contributes to its solidity.

According to a second aspect, the invention relates to a T-shaped connector for a hydrofoil foil assembly comprising a foil and a mast, the T-shaped connector comprising a first part which comprises means of fixing to the foil and a second part which comprises means of fixing to the mast and the T-shaped connector is pierced with a cavity opening onto a longitudinal through cavity in the mast, so that the two cavities together form a chamber making it possible to house elements useful for the operation of the hydrofoil.

According to a third aspect, the invention relates to a hydrofoil which comprises a foil assembly according to the invention.

The aims, advantages and particular characteristics of the T-shaped connector and the hydrofoil object of the present invention being similar to those of the hydrofoil foil assembly object of the present invention, they are not recalled here.

This description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

We note, from now on, that the figures are each to scale but that the scales between them can vary.show schematic views of a particular embodiment of a T-shaped connector. The T-shaped connector is shown alone, before assembly with the foil and mast of a foil assembly.

The T-shaped connectoris a structural element, ensuring the solidity of the connection between a mast and a foil which will be described in more detail with regard to. The T-shaped connector, the foil and the mast form a foil assembly.

The foil assembly is intended to be mounted under the hull of a hydrofoil to allow the hydrofoil to rise out of the water and maintain balance out of the water under speed. The hydrofoil (not shown) may have several sets of foils. According to a particular embodiment, the hydrofoil comprises three sets of foils, including one set of foils positioned under the hull, close to the bow of the hydrofoil, and two sets of foils positioned under the hull, close to the stern of the hydrofoil.

According to a preferred embodiment, the T connectoris obtained by assembling titanium plates. In other embodiments, the T-shaped connectoris comprised of any suitable metal or alloy to meet the weight and mechanical strength constraints. The T-shaped connector may include steel, polymers, composites, light alloys made from aluminum or light alloys made from magnesium.

According to a preferred embodiment, the T connectoris obtained by assembling plates, preferably made of titanium, welded together. This assembly is then machined to obtain at least one cavity and to draw the contours of the T connector in order to facilitate its assembly with the foil assembly.

The T-shaped connectorcomprises a first partconfigured to provide a solid junction between the T-shaped connector and the foil. The first partof the T-shaped connectoris a substantially flat part.

According to a particular embodiment, the first partis formed of two rigid plates,and, joined together. Said plates comprise an upper plateand a lower plate. Preferably, at least one of the platesandhas a domed shape or includes a cavity on its face intended to be mounted opposite the other plate,or, so that an openingis provided between the two plates when they are fixed together. The connection between the T-shaped connectorand the foil will be better understood with regard to the description of.

The T-shaped connectorcomprises a second partconfigured to provide a solid junction between the T-shaped connector and the mast. The second partis preferably a hollow part, substantially flat and of substantially rectangular or oblong section. The second partis linked solidly and at right angles to the first partof the T-shaped connector. A cavityis provided in the second part of the T-shaped connector.