INFLATABLE WING SAIL WITH AERO-OPTIMISED LEADING EDGE

State of the art

The invention concerns an innovative system for making an inflatable wing sail capable of reducing the cross-sections of the leading edge, producing positive effects on the efficiency and thus the performance of the sail forming the subject matter of the invention.

More specifically, this invention reveals the use of components capable of supporting the rigidity of the wing sail even when subjected to tensile and compressive stresses caused by the wind.

Prior art

Wing-foiling is a sport that was launched only a few years ago and is constantly evolving. It is definitely the water sport of the moment, given its rapid global success.

Wing-foiling involves sailing while holding a sail referred to as wing by means of handles, or by means of a boom, while standing balanced on a board that literally flies over the water.

The board manages to rise above the water through the use of an attachment called foil that generates lift like a common aeroplane wing: as speed increases, it provides increasing upward thrust.

Said foil allows any wing-foil user to literally fly over the water, minimising the friction typical of other water sports such as windsurfing, kite surfing and stand-up paddle boarding.

The sail used to keep the board moving is in not tethered to the board in any way, thus providing an unparalleled feeling of freedom.

The wing-foil sail is an inflatable, lightweight, floating element that provides the necessary thrust to move over the water and thus make the board fly.

Sail technology is constantly evolving and, year by year, brands experiment with new solutions that broaden and improve the conditions for practising the sport known as wing-foiling.

It is now easy to find many different types of sails, measuring between 2.8 and 9 square metres, for the purpose of enabling specialists to practise this sport with wind speeds of 8 to 40 knots.

In recent years, sail-making technology has progressed, and it is common to find four to five different types of wing-foil sails dedicated to different disciplines: freeride, freestyle, wave riding and speed sailing.

A wing-foil sail may include the use of a rigid boom, for the purpose of making said inflatable sail more rigid, thanks to the tension that the boom can exert along the entire sail.

When fitted with a rigid boom, said sail is very reactive, further increasing the effectiveness of the pumping technique commonly used to start sailing, accelerating quickly through a plurality of repetitive movements capable of increasing the propulsion of said sail.

However, this reactivity occurs not only during the start but also during sailing and surfing. The sail, in this case, is very sensitive since deformations due to the presence of inflatable tubes are limited.

The boom, however, being rigid, increases the weight of the sail and makes it more cumbersome to assemble and transport.

As a result, sails with soft handles have now conquered the market because, having no rigid elements, they are favourably light and practical to use.

Although less reactive, the sail is more stable in a neutral position and therefore particularly recommended for certain disciplines of this sport.

The inflatable wing sails used extensively in wing-foiling are, however, underperforming due to a growing demand from increasingly experienced and demanding sailors and surfers.

The inflatable tubes used to give rigidity to the structure supporting the sail are not sufficient to maintain their shape in the strongest wind conditions, or at high speeds. The maximum inflation pressure does not exceed 8 psi, and is therefore insufficient to maintain the required rigidity. The main problem concerns the deformation of the ends, which undoubtedly tend to modify the trailing edge profile, altering the sail's overall shape precisely during moments of maximum stress when professionals demand maximum performance.

The most popular brands have tried to solve this problem by simply increasing the crosssections of the inflatable tubes, which make up the leading edge of said sail. Although increasing cross-sections increases inflation pressures, it does not solve the main aerodynamic problem of the sport of wing-foiling, since at high speeds the resistance generated by large cross-sections generates turbulence that cannot be overlooked.

In the current state of the art, there are some registered inventions, such as the FR2663290, published on 20 December 1991, which solve the problem of wing-foil aerodynamics. Patent FR2663290, however, despite being considered the most relevant, discloses the construction of a plurality of inflatable sub-cells to subdivide the surface of a common parachute. Said invention cannot improve on dedicated wing-foil sails because it adopts methods and technologies that are now obsolete for this new sport, which is now of interest to most sailors and surfers around the world.

The purpose of the patent is therefore to revise the arrangement of the inner air chambers at the leading edge of said inflatable wing sails, revealing an innovative distribution of internal loads that can provide greater rigidity, in addition to a plurality of battens and fabrics capable of stiffening the ends of said wing sails designed specifically for the sport of wing -foiling.

Description of the invention

According to this invention, an inflatable wing sail with an aero-optimised leading edge is created which effectively solves the above-mentioned problems.

The inflatable wing sail forming the subject matter of the invention is capable of improving aerodynamic performance, which was previously compromised by the disproportionate cross-sections of the air chamber forming the leading edge of inflatable wing sails commonly used in wing-foiling.

In the sail described in this patent application, a bulkhead is inserted into said leading edge, for the purpose of reducing the internal volumes of the air chamber forming said leading edge. The insertion of said bulkhead makes it possible to reduce the crosssection of said leading edge, while maintaining high pressures that give the inflatable structure the rigidity necessary to maintain effective performance even when said sail is subjected to greater stress. Obtaining a double air chamber within said leading edge makes it possible to reach inflation pressures of 11 psi.

The rigidity of the wing sail forming the subject matter of the invention is further optimised by the insertion of a plurality of customisable battens inside a pocket attached to each end of said sail. Said ends are favourably stable and rigid even when the apparent wind speed puts greater stress on the sail forming the subject matter of the invention.

The leading edge, comprised within said sail, has a C-shape, and makes it easier to attach the sail to a generic fabric, forming a sail of variable surface area depending on the size of said leading edge. Said generic fabric, in one form of embodiment, can be attached to said leading edge by means of a zip made of plastic material, facilitating and speeding up any possible substitution of said material with a material of the same type but of different sizes; said substitution allows the user to choose the most suitable sail surface to sail with according to the weather conditions, while maintaining the same leading edge and the same boom.

Said leading edge comprises at least two inflatable air chambers that can be separated by a bulkhead sewn onto their inner walls, in order to reduce the overall cross-section of the leading edge, while maintaining high inflation pressures that can maintain high quality standards.

Said bulkhead, inserted internally into said leading edge, is suitable for obtaining two separate air chambers, in order to reduce the overall cross-section of said leading edge, while maintaining the same resistance properties due to the internal air pressure; said bulkhead includes a flap of fabric sewn by means of Dyneema thread, in order to confer even greater rigidity to the seams, reducing any elastic effect that causes rapid deterioration of the sail over time and with increasing assembly cycles. A small tube connects said two air chambers within said leading edge, in order to maintain the same inflation pressure in both chambers, reducing any overload and further facilitating the inflation process.

In order to favour the inflow of air inside and outside said leading edge, consequently determining the inflation and deflation of said wing sail, at least one inflation valve must be installed on one of the air chambers of said leading edge; said wing sail, once deprived of air in the inner air chambers, can be easily folded and stowed inside any backpack in order to facilitate its transport.

At least one inflatable boom, bound perpendicularly and centrally to said leading edge, allows the user to easily grasp it, by means of a plurality of commonly used soft handles; by means of said handles secured to said boom, said user can expose the whole inflatable wing sail to the wind, by changing its angle of attack with respect to the actual wind direction.

An outer pocket is installed at each end of said inflatable wing sail, for the purpose of accommodating any rigid batten that can maintain the overall shape of the entire leading edge, even when said sail is exposed to the force of the wind, which commonly tends to bend said leading edge, thus impairing its functionality.

In one form of construction, said outer pocket can accommodate a rigid monofilament that can provide the rigidity necessary to reduce flexing of the ends even when said inflatable wing sail is exposed to the wind, while maintaining reduced weight and bulk through the use of soft materials.

Battens can be inserted inside said outer pocket, at each end of said leading edge, and are further characterised by different physical properties, giving the user the possibility of favouring greater elasticity or greater resistance in all wind conditions; said battens can also be flexibly interconnected, by means of a plurality of joints capable of making two or more types of battens work together; this end stiffening system therefore proves to be favourably customisable, encouraging constant research and development on the part of each user. By way of example, but without limitation, said battens are capable of being tightened or loosened by means of a terminal installed on them, comprising a screw that can be screwed in to increase their total length, or unscrewed to decrease their total length.

Alternatively, the battens that are intended to be inserted inside said outer pocket are sewn internally to said outer pocket, but have a shorter length in order to continue to make it possible to insert the present inflatable wing sail inside a generic backpack.

In an embodiment thereof, a single long batten, having a total length equal to the length of the entire leading edge, is capable of performing the function of said battens, providing the present inflatable wing sail with the rigidity necessary to reduce the flexure of the ends; said long batten can further be removed at the end of use, allowing the user to store the entire inflatable wing sail inside a generic backpack.

The advantages offered by this invention are evident in the light of the foregoing description, and will be even clearer thanks to the attached figures and detailed description.

Description of the Figures

The invention will be described below in at least one preferred form of embodiment, using as an explanation but not limited to the attached figures, in which:

-FIGURE 1 shows an upper view, intended to show the characteristic C-shape of the leading edge 12 which is included in the inflatable wing sail structure forming the subject matter of the invention.

Said leading edge 12 is able to keep a generic fabric 10 taut and open in order to increase the sail surface of the whole sail.

Said fabric 10 is secured to said leading edge 12 and to a boom 13, further facilitating the grip of said sail by the user.

The leading edge 12, in view of its wingspan, has ends 15 which easily tend to flex when stressed by greater loads; for this reason, a bulkhead 14 is sewn inside said leading edge 12, in order to realise two separate air chambers 16, 17, suitable to increase the inflation pressures while decreasing the overall cross- section of the whole leading edge 12.

Said two air chambers 16, 17 are connected by a small tube 11, for the purpose of balancing the internal pressures.

-FIGURE 2 shows the lower side of the inflatable wing sail forming the subject matter of the invention; more particularly, the connection between said boom 13 and said leading edge 12 is shown, forming the minimum structure necessary to keep said generic fabric 10 taut and open during the use of said wing sail.

A plurality of soft handles 18 are installed on said boom 13, for the purpose of facilitating the grip and handling of said sail by any user.

A valve 19 is provided to allow the inflating and deflating phases of said leading edge 12, in order to facilitate the raising and lowering of this sail.

The ends 15 of said leading edge 12 are made stronger and more rigid by the use of an outer pocket 20, installed on each end 15, for the purpose of accommodating one or more battens.

Detailed description of the invention

This invention will now be illustrated by way of example only, but not by way of limitation or constraint, by appealing to the Figures which illustrate some embodiments in relation to the present inventive concept.

With reference to FIG. 1, the wing sail forming the subject matter of the invention is illustrated from an upper view, which allows the shape and structure of the leading edge 12 to be easily seen.

Due to the C-shape of the leading edge 12, it is able to make the sail rigid, allowing the generic 10 fabric to maintain its shape even in the most difficult conditions. The leading edge 12 can be attached to said generic fabric 10, constituting, together with a boom 13, the structure necessary to make the entire sail rigid and at the same time light and manoeuvrable.

The front edge 12, supporting the tensile and compressive stresses generated by the sail, is subject to numerous deformations occurring at the ends 15. To overcome said problem, a bulkhead 14 was inserted internally to said leading edge 12, for the purpose of obtaining at least two separate air chambers 16, 17, suitable to increase the inflation pressure values, while maintaining a smaller cross-section of said leading edge 12.

The inflation pressure, internal to said air chambers 16, 17 reaches 11 psi, favouring a total stiffening of the leading edge compared to inflatable wing sails of the prior art.

Decreasing the cross-section of leading edge 12 has considerable advantages at high speeds, as the larger sections generate more turbulence on the entire inflatable wing sail forming the subject matter of the invention.

However, the separate air chambers 16, 17 are connected through the use of a small tube 11, for the purpose of keeping the air pressure inside said air chambers 16, 17 balanced.

The use of said small tube 11 further favours the inflation, giving the manufacturer the possibility of using only one inflation valve 19 for both air chambers 16, 17.

With reference to FIG.2, the lower side of said inflatable wing sail is illustrated, in particular it is evident the presence of a boom 13 which facilitates the handling of said sail, in the conditions of use.

A plurality of soft handles 18 are secured to said boom 13, for the purpose of more effectively orienting the whole sail during sailing.

A single inflation valve 19 is installed on the inner flap of said leading edge 12, for the purpose of facilitating the flow of air in and out of said air chambers 16, 17. The ends 15 of said leading edge 12 comprise an outer pocket 20 each, for the purpose of accommodating a plurality of rigid battens which can impart even more rigidity to the entire inflatable wing sail when subjected to greater stresses at high speeds.

Said outer pockets 20 can further accommodate a rigid monofilament that can provide the same strength as a rigid batten.

Finally, it is clear that modifications, additions or variations obvious to a person skilled in the art may be made to the invention described herein, without departing from the scope of protection provided by the attached claims.