Ground-effect maritime craft of the flying-boat type

Abstract

The present invention relates to a ground-effect maritime craft (1) of the flying-boat type, comprising at least one hull (2) and an aerofoil having a pair of front wings (3) and a pair of rear wings (4) having an aerodynamic profile with a suction side (40) on top, as well as side panels (5) connecting the front wings (3) and the rear wings (4); in alignment with each of the side panels (5), two plates (6) projecting on top of and from a nascent end (60) to an upper end (61) forming a leading edge inclined in an ascending manner on top from the front to the rear of the craft (1); the nascent end (60) of each of the two plates (6) being located at the suction side (40) of each rear wing (4) within the upstream portion (400) of each rear wing (4).

Description

[0001] GROUND-EFFECT MARITIME CRAFT OF THE FLYING BOAT TYPE

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention falls within the field of maritime navigation.

[0004] The invention relates to a maritime craft, such as a ship or boat, intended for navigation on a body of water, such as a sea or an ocean, or even a lake.

[0005] For this purpose, the vessel is equipped with a hull, ensuring the majority of its buoyancy.

[0006] More specifically, the invention relates to a ground effect maritime craft, namely that such a craft generates an aerodynamic ground effect phenomenon, in order to maintain itself in flight, thus resembling a boat-plane, or also called a "navion" (contraction of "navire-avion"), commonly designated "GEV" (for "Ground Effect Vehicle") or "WIG" (for "Wing In Ground effect").

[0007] To impart such a ground effect to the vessel, the hull must be equipped with one or more aerodynamic lifting surfaces, generally in the form of an aerodynamic wing with at least one pair of wings extending laterally on either side of the hull in a nearly horizontal plane. These wings have an aerodynamic profile, with an upper and lower surface connected upstream by a leading edge and downstream by a trailing edge. The wings then form a virtual nozzle with the water surface at their lower end, creating a high-pressure cushion that increases aerodynamic performance.

[0008] To increase lift and performance, it is common practice to equip the wingtips with wingtip plates, usually called "endplates," extending almost vertically above the wing plane. To improve ground effect, these plates enhance the tunnel effect and limit flow recirculation at the wingtips.

[0009] In addition, such a plate can serve as a float at the wingtips, preventing tipping while afloat and limiting roll during planing and landing maneuvers, as well as when moving afloat.

[0010] In a specific case of two pairs of wings, located at the front and rear, allowing for increased aerodynamic lift, the side plates then connect the ends of the front and rear wings on each side, protecting each rear wing from the effects of the vortices generated by each front wing, which are detrimental to the aerodynamics of the rear wings.

[0011] In addition, it should be noted that a ground effect flying craft allows the craft to be raised to a limited height, up to a few meters above the water, on the order of 10% to 20% (percent) of the length of the craft.

[0012] This ground-effect craft is then akin to a "flying boat." Furthermore, a ground-effect craft of the flying boat type includes other elements necessary for its maneuvers, both afloat and in flight, and attached to the hull. In particular, the craft includes at least one central rudder, receiving a control surface, but preferably two rudders positioned on either side of the craft, aligned with the side plates.

[0013] Each fin has a roughly triangular shape, with a truncated distal end, and a front edge that slopes upwards from the front to the rear of the boat.

[0014] Furthermore, each fin serves as a support for a plane, extending horizontally at the distal end. This plane receives one or preferably several flaps, commonly referred to as "rear flaps".

[0015] STATE OF THE ART

[0016] However, a drawback of a boat equipped with a pair of forward and a pair of aft wings connected by side plates lies in the vortex sheets generated by airflow, particularly the airflow over the forward wings, which impacts the flow over the aft wings. Furthermore, the flow from the leading edge of each wing, both forward and aft, also generates vortices that impact the flow on the trailing edge of each wing. These vortices can be of various types, such as the drag generated by the forward wings and the wake effect, but also the vortices generated at the tips of both the forward and aft wings.

[0017] These turbulences alter the aerodynamics and especially the lift of the wings, particularly the rear wings, which is all the more detrimental for a ground-effect craft.

[0018] The insertion of lateral plates reduces the circulation of vortices at the wingtips, particularly through an upper portion extending above the wings, as well as potentially a lower portion extending below the depression formed by the lower surface or the angle of the wings. In short, the plates laterally block some of the airflow at the wingtips. However, longitudinally, the lift of the rear wings remains significantly affected by the turbulence generated by the front wing.

[0019] In particular, a vortex circulation is generated at each wingtip, from the lower surface to the upper surface, essentially following an airflow path resembling a spiraling vortex sheet. Furthermore, these spiraling vortices significantly reduce the nozzle effect desired for a ground-effect craft.

[0020] Documents JP H04 173465 and JP H03 1 12765 describe examples of ground-effect marine craft, equipped with a pair of front wings and a pair of rear wings, the wingtips of which on the same side are connected by a plate.

[0021] Furthermore, behind each rear wing, at a decreasing point on the upper surface, fins are fitted to support an additional horizontal lift surface, as well as control surfaces for steering the craft. Each fin, generally triangular in shape, projects from the upper edge of each plate and has a sloping leading edge.

[0022] Such fins are not intended to limit the vortex flow at the rear of the upper surface of each rear wing, due to their placement well behind in the decreasing portion of said upper surface.

[0023] DESCRIPTION OF THE INVENTION

[0024] The invention aims to overcome the drawbacks of the state of the art by proposing a ground-effect maritime craft, of the flying boat type, with two pairs of front and rear wings, connected by lateral plates, with an aerodynamic configuration, improving air circulation between the front and rear wings and limiting vortex sheets, in particular reducing the vortices generated by each front wing and impacting the lift of the rear wings.

[0025] To achieve this, the invention plans to combine several aerodynamic profile characteristics, making it possible to limit the flow at the wingtips, both laterally and longitudinally.

[0026] In particular, the side plates are designed to extend above the extrados, but especially below the intrados of each wing, allowing the vortex flow coming from the circulation at the tip and under each wing in the lower part to be blocked laterally.

[0027] Indeed, in flight, vortex zones form under the wings, expelling air from the ground effect cushion in a direction extending laterally outwards, in the form of generally circular and concentric flows. These lateral turbulences originate primarily from aerodynamic effects, combined with ground effect, induced, on the one hand, downstream or rearward by the forward wing and, on the other hand, at the leading edge and the leading portion of the rear wings. In particular, the leading portion of the upper surface generates a low pressure that tends to draw air from the vortex zones, which then passes over the upper edge of each wing plate. This aerodynamic phenomenon generates an overpressure, which combines with and deflects the acceleration flow from the upper surface to the leading portion, pushing it towards the center of the wing.

[0028] Furthermore, plates are added to the rear section of the lateral plates, extending them upwards. Similar in form to the fin(s), these plates laterally block a portion of the turbulent flow in the upper part of the wing. The precise positioning of the plates is specifically chosen: the beginning of each plate is located at the upstream portion of the upper surface of each rear wing, before the tapering airfoil. Each plate thus forms a vertically increasing surface area that blocks the aforementioned turbulence, preventing the flow from passing over the plates downstream of each rear wing, thereby limiting the impact and suction at this point on the upper surface.

[0029] In addition, these protruding plates then serve as a support for the flap plane, connected to the fin(s), stiffening the structure of the boat at this level.

[0030] Thus, the invention relates to a ground-effect maritime craft, of the flying boat type, comprising

[0031] - at least one hull, equipped with a horizontal plane extending longitudinally and parallel above a waterline,

[0032] - a wing forming an aerodynamic lift emerging along said horizontal plane and provided with i) at least one pair of forward wings extending symmetrically on either side of the right and left sides of said hull, with forward proximal ends connected to said hull and forward distal ends; ii) at least one pair of rear wings extending symmetrically on either side of the right and left sides of said hull, with rear proximal ends connected to said hull and rear distal ends;

[0033] - each of the rear wings having an aerodynamic profile with an upper surface comprising an upstream portion increasing from a leading edge to a point where it passes through a tangent parallel to said horizontal plane and a downstream portion decreasing from said point of passage to a trailing edge; the craft further comprising

[0034] - lateral plates, each of the lateral plates connecting the distal front end of one of the front wings and the distal rear end of one of the rear wings located on the same side;

[0035] - in alignment with each of the side plates, two plates extending upwards from a nascent end to an upper end forming a front edge inclined increasingly upwards from the front to the rear of the boat;

[0036] - said emerging end of each of the two plates located at the level of the extrados of each rear wing.

[0037] Such a maritime vessel is characterized in that the said emerging end of each of the two plates is located within the downstream portion of each rear wing.

[0038] According to additional, non-limiting characteristics, such a vessel may include: - at least one centerboard, extending upwards from said hull from a base to a distal end and equipped with at least one control rudder;

[0039] - a plane equipped with control flaps and mounted at each distal end of said at least one fin; and in that

[0040] - the upper end of each of the two plates is connected to the levels of the ends of said plane.

[0041] According to one embodiment, said plane extends horizontally, said plates having at least the corresponding height relative to said at least one fin.

[0042] According to one embodiment, said plane extends along at least one inclined portion between said at least one fin and each of said two plates, each plate having at least one lower height relative to said at least one fin.

[0043] According to one embodiment, each of said side plates extends in projection below the front wings and rear wings.

[0044] According to one embodiment, each of said side plates extends in projection above the front wings and the rear wings.

[0045] According to one embodiment, each of the two plates extends in the continuation and continuity of each of the side plates.

[0046] According to one embodiment, each of the plates includes a propeller mounted within a faired housing.

[0047] PRESENTATION OF THE DRAWINGS

[0048] Other features and advantages of the invention will become apparent from the following detailed description of non-limiting embodiments of the invention, with reference to the accompanying figures, in which:

[0049] [Fig. 1] schematically represents a perspective view of one embodiment of a boat, with a sail equipped with two pairs of front and rear wings, as well as plates according to a first configuration in superior extension of the lateral plates, showing in particular the emerging end of each plate at the level of the upstream portion of the rear wings;

[0050] [Fig. 2] schematically represents a view similar to figure 1 of another embodiment of a boat according to a second configuration of the plates, showing in particular the emerging end of each plate at the level of the downstream portion of each rear wing, as well as a plane extending at an inclined angle between each fin and each plate;

[0051] [Fig. 3] schematically represents a side view of one embodiment of a boat, showing in particular the side plates protruding above but also below respectively the extrados and intrados of the front and rear wings, as well as the emerging end of a plate in relation to the upstream portion of a rear wing;

[0052] [Fig. 4] schematically represents a simplified elevation view of one embodiment of a boat, with a magnification in side view highlighting the emerging end of a plate in relation to the upstream portion of one of the rear wings;

[0053] [Fig. 5] schematically represents a side view of a first embodiment, showing the position of the nascent end of a plate in an upstream portion of a rear wing, located between the leading edge and the point of passage of a horizontal tangent to the extrados of said rear wing, as well as a plate with a height equivalent to the height of a fin;

[0054] [Fig. 6] schematically represents a view similar to figure 5 of another embodiment of a plate, showing another longer upstream portion of the rear wing between the leading edge and said passing point, as well as a plate of a lower height than a fin;

[0055] [Fig. 7] schematically represents a view similar to Figure 5 of a second embodiment of a plate, showing the position of the emerging end of a plate in a downstream portion of a rear wing, located between the trailing edge and the point of passage of a horizontal tangent to the upper surface of said rear wing; and

[0056] [Fig. 8] schematically represents a partial perspective view of an embodiment showing the junction of a front wing with a side plate, with a magnification seen from the front highlighting the heights of said plate above the extrados and below the intrados of said front wing.

[0057] DETAILED DESCRIPTION

[0058] The present invention falls within the field of maritime navigation and relates to a maritime vessel 1, hereinafter referred to as "vehicle 1".

[0059] Such a vessel 1 comprises at least one hull 2.

[0060] According to one embodiment, the vessel 1 is preferably monohull and comprises a single hull 2.

[0061] According to another embodiment, the vessel 1 may be provided as a multihull, comprising at least two hulls 2, connected superiorly to each other.

[0062] Further on, said at least one hull 2 ​​is provided with a plane AA' extending longitudinally and parallel above a waterline. Said plane AA' may also be confused with said waterline.

[0063] It should be noted that the waterline is understood to be when the vessel 1 is afloat at rest, with its mass evenly distributed with respect to the Archimedes' thrust induced on its partially submerged hull(s) 2, and on a calm water surface, free from swell or waves, i.e., essentially flat. Therefore, the plan A-A' extends horizontally or substantially horizontally. Furthermore, the hull 2 ​​is provided with at least two lateral walls 20 forming a hull below the waterline, i.e., below the plan A-A'. These lateral walls 20 are joined below at the level of a keel line 21 extending to a rear end, forming a stern 22. On the other side, at the bow 23, the at least two lateral walls 20 extend forward to a junction forming a stem 24.

[0064] Thus, the 20 contiguous side walls delimit an interior volume, ensuring at least in part the buoyancy of the vessel 1.

[0065] Such a vessel 1 also includes a center of gravity. This center of gravity depends on the mass of vessel 1 and the distribution of its load on board. This center of gravity defines a center of equilibrium, around which vessel 1 pitches, particularly during planing and landing.

[0066] Accordingly, according to the invention, the maritime vessel 1 is designed to have a ground effect, namely that such a vessel 1 generates an aerodynamic ground effect phenomenon, in order to maintain itself in flight.

[0067] To this end, the craft 1 comprises a sail providing aerodynamic lift along said horizontal plane. In particular, the sail is provided with at least one pair of forward wings 3 extending symmetrically on either side of the right and left sides of said hull 2, with forward proximal ends connected to said hull 2 ​​and forward distal ends. The sail is also provided with at least one pair of aft wings 4 extending symmetrically on either side of the right and left sides of said hull 2, with aft proximal ends connected to said hull and aft distal ends.

[0068] Therefore, ground-effect craft 1 is of the flying boat type.

[0069] It should be noted that vessel 1 can incorporate various aerodynamic elements, necessary to ensure its movements and maneuvers.

[0070] In particular, craft 1 may include a propulsion system generating sufficient thrust to get on plane and land on water, as well as to generate the speed required to generate ground effect.

[0071] In particular, the wings 3,4 have an aerodynamic profile which, especially with the hull profile 2, in flight, generates a virtual nozzle with the water surface below, forming an overpressure cushion which increases aerodynamic performance.

[0072] In addition, craft 1 may include a hull equipped with a cockpit and a pilot's position; said hull may form a fuselage comprising at least in its lower part by said hull at least a hull 2.

[0073] Furthermore, the craft 1 can carry equipment dedicated to its control and maneuvering, such as avionics. According to the invention, the craft 1 also includes lateral plates 5. Each of the lateral plates 5 connects the forward distal end of one of the forward wings 3 and the aft distal end of one of the aft wings 4 located on the same side. In other words, the tips of the wings 3, 4 located on the right and left are connected by a corresponding lateral plate 5.

[0074] Further on, preferably, the said lateral plates 5 can extend vertically or substantially vertically.

[0075] Furthermore, the craft 1 includes, aligned with each of the lateral plates 5, two plates 6 extending upwards from a nascent end 60 to a superior end 61. Each of the plates 6 forms a frontal edge inclined upwards from the front to the rear of the craft 1. In other words, the plates 6 rise vertically from the top of the plates 5, with a sloping profile.

[0076] In one embodiment, each of the two plates 6 extends in line with and in continuity with each of the lateral plates 5. In other words, each plate 6 is located and is generally contained in the same vertical plane as the corresponding lateral plate 5.

[0077] According to an alternative embodiment, each plate 6 can extend laterally at an angle, outwards but preferably inwards from the vertical plane containing globally the corresponding lateral plate 5.

[0078] Further forward, each of the rear wings 4 has an aerodynamic profile with an uppermost extrados 40 comprising an upstream portion 400 increasing from a leading edge 42 to a point 401 of passage of a tangent parallel to said horizontal plane and a downstream portion 402 decreasing from said point 401 of passage to a trailing edge 43.

[0079] In a related way, the aerodynamic profile of each of the forward wings 3 also includes below an intrados 31, located in a rounded and concave shape.

[0080] It should be noted that the front wings 3 also include a similar aerodynamic profile, namely with an extrados 30, an intrados 31, from a leading edge 32 to a trailing edge 33.

[0081] According to one embodiment, each of said lateral plates 5 projects below the forward wings 3 and the rear wings 4. In other words, the plates 5 have a height hl that extends below the wings 3,4, in particular below the leading edges 32,42 and / or below the trailing edges 33,43 of the wings 3,4. In short, the height of plate 5 below the wing 3,4 is understood to be relative to the lowest point, preferably relative to the trailing edge 33,43, as seen in the example in Figure 8.

[0082] According to one embodiment, each of said lateral plates 5 extends downwards to a predetermined height hl. The height hi of the plates 5 under the wings 3,4 limits the flow of vortex sheets generated from the lower surfaces 31,41, namely by providing a vertical surface for blocking a portion of the vortices flowing laterally from the lower surface 31 towards the distal end of the wings 3,4.

[0083] According to one embodiment, each of said lateral plates 5 projects above the front wings 3 and the rear wings 4. In other words, the plates 5 have a height h2 which protrudes superiorly, in particular above the extrados 30,40, namely above the highest point of the extrados 30,40, in particular the point of passage 401 of the rear wings 4.

[0084] According to one embodiment, each of said lateral plates 5 extends superiorly over a determined height h2.

[0085] The height h2 of the plates 5 above the wings 3,4 allows to limit the flow at least part of the vortex sheets generated laterally from the outside to the inside.

[0086] Advantageously, the emerging end 60 of each of the two plates 6 is located at the level of the upper surface 40 of each rear wing 4. In other words, each of the plates 6 begins at the level of each rear wing 4.

[0087] Such a configuration of the plates 6 extending above the rear wings 4 limits the flow of vortex sheets induced at least by the forward wings 3, which would otherwise impact the lift of the rear wings 4. In other words, the height of the plates 5 above the rear wings 4 limits the flow of some of the vortex sheets by providing a vertical surface to block some of the vortices flowing laterally from the distal end of the wings 3,4 towards the upper surface 40.

[0088] Figure 4 highlights a nascent end 60 located at the level of the extrados 40 of a rear wing 4, in particular located in the upstream portion 400.

[0089] Advantageously, the invention provides that the emerging end 60 of each of the two plates 6 is located within the upstream portion 400 of each rear wing 4. In other words, each plate 6 begins in the forward part of each rear wing 4.

[0090] In particular, the emerging end of each plate 6 also protrudes at the junction of the rear wings 4 with the lateral plates 5, at a point where a tangent to the extrados forms with a straight or horizontal plane, or forms an inclined and increasing plane from front to back (i.e. in the increasing curvature of said extrados), in order to obtain the blocking of the flow fluxes which previously overflowed over the plates 5 and came to impact and deflect the acceleration flux at this level of each rear wing 4.

[0091] Corresponding variants, with different shapes of plates 6, are visible in Figures 5 and 6. According to an alternative embodiment, as seen in Figure 7, the emerging end 60 of each of the two plates 6 is located within the downstream portion 402 of each rear wing 4. In other words, each plate 6 begins in the rear part of each rear wing 4.

[0092] According to one embodiment, not shown, each of the plates 6 includes a propeller mounted within a faired housing. Such a propeller is thus integrated within each plate 6, enabling lateral control during maneuvers of the craft 1, similar to a tail rotor or anti-torque rotor (ACR) of a helicopter. In particular, such a faired housing is then similar to a fenestron housing the tail rotor of a helicopter.

[0093] According to one embodiment, the boat 1 comprises at least one centerboard 7, extending superiorly from said hull 2 ​​from a base to a distal end.

[0094] The boat may include a single keel 7, as seen in Figure 1, or several keels 7, in particular two keels 7 as seen in Figure 2.

[0095] In addition, each fin 7 is equipped with at least one control rudder.

[0096] According to this embodiment, the craft also includes a plan 8 mounted at each distal end of said at least one fin 7.

[0097] In particular, in the case of several fins 7, the plane 8 joins each of the fins 7 at the top.

[0098] Depending on different configurations, the fin(s) 7 can extend vertically, as seen in Figure 1, or be inclined with respect to the vertical, as seen in Figure 2.

[0099] In addition, such a Plan 8 is equipped with control flaps, including flaps ensuring depth control.

[0100] Further on, the upper end 61 of each of the two plates 6 is connected to the levels of the ends of said plane 8.

[0101] According to one embodiment, said plane 8 extends horizontally, said plates 6 then having at least the corresponding height relative to said at least one fin 7. In short, the plates 6 are high enough to ensure their connection with the plane 8.

[0102] An example of such a configuration can be seen in Figure 1.

[0103] According to another embodiment, said plane 8 extends along at least one inclined portion 80 between said at least one fin 7 and each of said two plates 6. Therefore, each plate 6 has at least one lower height relative to said at least one fin 7.

[0104] According to a preferred configuration, the craft 1 comprises two symmetrically inclined fins 7, on the right and left sides, forming a V. The plane 8 has inclined portions 80 connecting each of the two fins 7 to each plate 6, as well as a horizontal portion 81 between the fins 7.

[0105] An example of such a configuration can be seen in Figure 1.

Claims

DEMANDS 1. Ground-effect maritime craft (1), of the flying boat type, comprising - at least one hull (2), equipped with a plan (AA 1 ) horizontal extending longitudinally and parallel above a waterline, - a wing forming an aerodynamic lift emerging along said plane (AA 1 ) horizontal and provided with i) at least one pair (3) of forewings extending symmetrically on either side of the right and left sides of said hull (2), with proximal front extremities connected to said hull (2) and distal front extremities; ii) at least one pair (4) of hindwings extending symmetrically on either side of the right and left sides of said hull (2), with proximal rear extremities connected to said hull (2) and distal rear extremities; - each of the rear wings (4) having an aerodynamic profile with an upper surface (40) comprising an upstream portion (400) increasing from a leading edge (42) to a point (401) of passage of a tangent parallel to said plane (AA 1 ) horizontal and a decreasing downstream portion (402) from said point (401) of passage to a trailing edge (43); the craft (1) further comprising - lateral plates (5), each of the lateral plates (5) connecting the front distal end of one of the front wings (3) and the rear distal end of one of the rear wings (4) located on the same side; - in alignment with each of the lateral plates (5), two plates (6) extending upwards from a nascent end (60) to an upper end (61) forming a front edge inclined increasingly upwards from the front to the rear of the craft (1); - said emerging end (60) of each of the two plates (6) located at the level of the upper surface (40) of each rear wing (4); characterized in that - said emerging end (60) of each of the two plates (6) is located within the upstream portion (400) of each rear wing (4).

2. A maritime vessel (1) according to the preceding claim, characterized in that it comprises - at least one fin (7), extending upwards from said hull (2) from a base to a distal end and provided with at least one control rudder; - a plane (8) equipped with control flaps and mounted at each distal end of said at least one fin (7); and in that - the upper end (61) of each of the two plates (6) is connected to the levels of the ends of said plane (8).

3. Sea craft (1) according to the preceding claim, characterized in that - said plane (8) extends horizontally, said plates (6) having at least the corresponding height in relation to said at least one fin (7).

4. Sea craft (1) according to any one of claims 2 or 3, characterized in that - said plane (8) extends along at least one inclined portion (80) between said at least one fin (7) and each of said two plates (6), each plate (6) having at least one lower height in relation to said at least one fin (7).

5. A maritime vessel (1) according to any one of the preceding claims, characterized in that - each of the said lateral plates (5) extends in projection below the front wings (3) and the rear wings (4).

6. A maritime vessel (1) according to any one of the preceding claims, characterized in that - each of the said lateral plates (5) extends in projection above the front wings (3) and the rear wings (4).

7. A maritime vessel (1) according to any one of the preceding claims, characterized in that - each of the two plates (6) extends in the continuation and continuity of each of the lateral plates (5).

8. A maritime vessel (1) according to any one of the preceding claims, characterized in that - each of the plates (6) includes a propeller mounted within a faired housing.

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