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 a wing assembly having a pair of front wings (3) and a pair of rear wings (4), as well as side plates (5) that have an outer wall (50) and an inner wall (51), an upper edge (52) and a lower edge (53), the inner wall (51) of each of the side plates (5) connecting the front distal end of one of the front wings (3) and the rear wings (4), characterised in that the upper edge (52) of each of the side plates (5) projects above the front wings (3) and the rear wings (4). In addition, the upper edge (52) has an outer profile that diverges upwards with respect to the outer wall (50) of the plate (2).

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] Document JP H03 1 12765 describes an example of such a ground-effect marine craft, equipped with a pair of forward wings and a pair of rear wings, the wingtips of which on the same side are connected by a plate. Furthermore, 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% of the craft's length.

[0012] This ground-effect craft is then akin to a "flying boat".

[0013] STATE OF THE ART

[0014] 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, and especially, the vortices generated at the wingtips.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] To achieve this, the invention combines several aerodynamic profile features to limit wingtip flow, both laterally and longitudinally. Specifically, the side plates are designed to extend beyond the upper surface (extrados) and below the lower surface (intrados) of each wing, thereby blocking the turbulent flow originating from the circulation at the wingtip and beneath each wing.

[0021] Furthermore, the upper edge of each plate, projecting above the extrados, has an external profile that diverges upwards relative to the outer face of the corresponding plate. In other words, the upper edge of each plate diverges outwards from bottom to top relative to the longitudinal median plane of each plate.

[0022] The airflow along such a profile of the upper edge of each plate is modified, pushed outwards, thus limiting part of the vortex sheets which impact the lift of the wings, both front and rear.

[0023] Thus, the invention relates to a ground-effect maritime craft, of the flying boat type, comprising

[0024] - at least one hull, equipped with a horizontal plane extending longitudinally and parallel above a waterline,

[0025] - 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;

[0026] - each rear wing having an aerodynamic profile with an upper surface (extrados) and an upper surface (intrados) connected upstream by a leading edge and downstream by a trailing edge; the craft also comprising

[0027] - lateral plates, with an outer wall and an inner wall, an upper edge and an lower edge, the inner wall of each of the lateral plates connecting the distal front end of one of the forewings and the distal rear end of one of the rearwings located on the same side.

[0028] Such a maritime vessel is characterized by the fact that

[0029] - the upper edge of each of the said side plates extends in projection above the front wings and the rear wings;

[0030] - said upper edge comprises an external profile diverging upwards with respect to the external wall of the plate. According to additional, non-limiting characteristics, the external profile of the upper edge of each side plate has a convex shape of geometric cross-section.

[0031] According to one embodiment, said external profile of the upper edge of each side plate has a convex shape with a rounded cross-section.

[0032] According to one embodiment, each side plate includes a front edge extending said upper edge with a similar profile.

[0033] According to one embodiment, said upper edge forms a roll of an elastic material.

[0034] According to one embodiment, the marine vessel includes, at a junction between the inner wall of each side plate and the extrados of each of the front and / or rear wings, a wedge-shaped flow fairing.

[0035] According to one embodiment, said fairing is located at a decreasing downstream portion of said wing extending from a point of passage of a tangent parallel to said horizontal plane to the trailing edge.

[0036] According to one embodiment, said fairing has a convex and rounded aerodynamic profile, extending

[0037] - at an angle between the extrados and the inner wall of each lateral plate,

[0038] - in a divergent manner from upstream to downstream until a reversing point.

[0039] According to one embodiment, the aerodynamic profile of said fairing extends convergently from said point of reversal to the trailing edge of the upper surface of the corresponding wing.

[0040] According to one embodiment, each of said side plates extends in projection below the front wings and rear wings.

[0041] PRESENTATION OF THE DRAWINGS

[0042] 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:

[0043] [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 connected by lateral plates, showing in particular the upper edge of the plates equipped with a profile in the form of a sausage;

[0044] [Fig. 2] schematically represents a view similar to figure 1 of an embodiment of a boat, showing in particular a second configuration of inclined fins and plates connected to a support plane for control flaps;

[0045] [Fig. 3] schematically represents a perspective view from below of an embodiment of a boat, showing in particular a tube extended at the front edge of a side plate; [Fig. 4] schematically represents a partial perspective view of an embodiment of an upper edge of a side plate, with a magnification according to a vertical cross-section highlighting an example of the specific shape of said upper edge;

[0046] [Fig. 5] schematically represents a side view of an embodiment of a boat, showing in particular the side plates extending above but also below respectively the extrados and intrados of the front and rear wings, as well as the aerodynamic profile of the upper edge of a side plate extending from the front edge to said side plate;

[0047] [Fig. 6] schematically represents a top view of one embodiment of a boat, showing in particular fairings located between the extrados and the inner wall of each of the side plates;

[0048] [Fig. 7] schematically represents a three-quarter front perspective view of a detail from figure 6, showing in particular a specific shape of the aerodynamic profile of one of the fairings located between one of the side plates and a front wing; and

[0049] [Fig. 8] schematically represents a three-quarter rear perspective view of the fairing of figure 7.

[0050] DETAILED DESCRIPTION

[0051] The present invention falls within the field of maritime navigation and relates to a maritime vessel 1, hereinafter referred to as "vehicle 1".

[0052] Such a vessel 1 comprises at least one hull 2.

[0053] According to one embodiment, the vessel 1 is preferably monohull and comprises a single hull 2.

[0054] According to another embodiment, the vessel 1 may be provided as a multihull, comprising at least two hulls 2, connected superiorly to each other.

[0055] 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.

[0056] It should be noted that the waterline is defined as the waterline when the vessel 1 is afloat at rest, with its mass evenly distributed with respect to the buoyant force exerted on its partially submerged hull(s) 2, and on a calm water surface, free from swell or waves, i.e., essentially flat. Therefore, the plane A-A' extends horizontally or substantially horizontally.

[0057] Furthermore, said hull 2 ​​is provided with at least two lateral walls 20 forming a hull below said waterline, namely below said plane 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, said at least two lateral walls 20 extend frontally to a junction forming a stem 24.

[0058] Thus, the 20 contiguous side walls delimit an interior volume, ensuring at least in part the buoyancy of the vessel 1.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In particular, each of the rear wings 4 has an aerodynamic profile with an uppermost extrados 40 extending from a leading edge 42, i.e. located towards the front, to a trailing edge 43, i.e. located towards the rear.

[0063] In a related manner, 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.

[0064] Therefore, ground-effect craft 1 is of the flying boat type.

[0065] It should be noted that vessel 1 can incorporate various aerodynamic elements, necessary to ensure its movements and maneuvers.

[0066] 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.

[0067] 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.

[0068] In addition, vessel 1 may include a hull equipped with a cockpit and a pilot's seat; said hull may form a fuselage comprising at least in its lower part by said hull at least one hull 2. Furthermore, vessel 1 may carry equipment dedicated to its control and maneuvers, such as avionics.

[0069] According to the invention, the craft 1 further comprises lateral plates 5. Each of the lateral plates 5 connects the forward distal end of one of the forward wings 3 and the rear distal end of one of the rear 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.

[0070] More specifically, the lateral plates 5 comprise an outer wall 50 and an inner wall 51, as well as an upper edge 52 and a lower edge 53. Therefore, the inner wall 51 of each of the lateral plates 5 connects the forward distal end of one of the forward wings 3 and the rear distal end of one of the rear wings 4 located on the same side of the craft 1, namely the right or left side.

[0071] Further on, preferably, the said lateral plates 5 can extend vertically or substantially vertically.

[0072] According to one embodiment, each of said lateral plates 5 projects below the leading edges 3 and the trailing edges 4. In other words, the plates 5 have a height hl that extends below the wings 3,4; in particular, the height hl is the vertical distance between the lower edge 53 and 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 measured relative to the lowest point, preferably relative to the trailing edge 33,43, as shown in the example in Figure 8.

[0073] According to one embodiment, each of said lateral plates 5 extends downwards over a determined height hl.

[0074] The height hl of the plates 5 under the wings 3,4 allows to limit the flow of the vortex sheets generated from the intrados 31,41, namely offering a vertical surface of blocking part of the vortices flowing in a lateral direction from the intrados 31 towards the distal end of the wings 3,4.

[0075] Further on, craft 1 is characterized in that the upper edge 52 of each of the said lateral plates 5 projects beyond the forward wings 3 and the rear wings 4. In other words, each of the said lateral plates 5 projects beyond the forward wings 3 and the rear wings 4. In other words, the plates 5 have a height h2 that protrudes superiorly, particularly above the extrados 30,40, namely that the height h2 is the vertical distance between the upper edge 52 and the highest point of the extrados 30,40.

[0076] According to one embodiment, each of said lateral plates 5 extends superiorly over a determined height h2.

[0077] The height h2 of the plates 5 above the wings 3,4 limits the flow of at least some of the vortex sheets generated laterally from the outside in. Furthermore, the upper edge 52 has an external profile that diverges upwards relative to the outer wall 50 of the plate 5. In other words, at the top of each plate 5, the surface of the outer wall 50 extends outwards from the bottom upwards.

[0078] According to one embodiment, the external profile of the upper edge 52 of each lateral plate 5 has a convex shape with a geometric cross-section. In other words, the cross-section of the profile resembles a polygon.

[0079] According to one embodiment, the external profile of the upper edge 52 of each lateral plate 5 has a convex shape with a rounded cross-section. Such an embodiment is particularly visible in Figure 4, showing a substantially circular or disc-shaped rounded cross-section that joins the surface of the external wall 50 through a rounded or arched concave recess.

[0080] According to one embodiment, each side plate 5 includes a front edge 54 extending said upper edge 52 with a similar profile, namely that which deviates from the external face of the external wall 50.

[0081] According to a preferred embodiment, the front edge 54 comprises a lower portion 55 converging towards the lower edge 53 of each lateral plate 5. In other words, the lower portion 55 of the front edge 54 is inclined and approaches each lateral plate 5 as it descends. This lower portion 55 of the front edge 54 may be rounded or straight, like a bevel, as seen in Figure 4.

[0082] Thus, the offset of the upper edge 52 forms a deflector for the airflow, in particular for the vortex sheets: the airflow is guided upwards and outwards, limiting the impact on the upper surface 30,40 of the wings 3,4.

[0083] According to one embodiment, the upper edge 52 forms a bead 500 made of an elastic material, namely that the upper edge 52 comprises a piece attached to and fixed to the corresponding lateral plate 5. Furthermore, the semi-rigid or flexible material, in particular, possesses elasticity or resilience that allows it to deform from an initial position and return to that initial position without affecting the physical properties of said material.

[0084] Alternatively, said upper edge 52 may be made of a rigid, shock-resistant material.

[0085] In yet another embodiment, the upper edge 52 can be made of a combination of rigid and flexible materials, in particular a rigid outer material and a flexible or semi-rigid inner material serving as a shock absorber. For example, the outer material can be metallic or composite, while the inner material can be an expanded material. In one embodiment, the material of the tube 500, internally and / or externally, can be selected from plastics or composites, an elastomer, or natural or synthetic rubber.

[0086] According to yet another embodiment, the 500 elastic sausage can be hollow, or with an internal honeycomb structure, in order to reduce the weight while retaining its elasticity.

[0087] Such a 500 elastic, rigid or combined inflatable tube serves as protection, particularly when docking at a quay or with another maritime vessel.

[0088] According to one embodiment, the craft 1 includes, at a junction between the inner wall 51 of each lateral plate 5 and the upper surface 30, 40 of each of the forward and / or aft wings 3, 4, a wedge-shaped flow fairing 6. In other words, each forward wing 3 includes a fairing 6 and / or each aft wing 4 includes a fairing 6.

[0089] According to one embodiment, said fairing 6 is located at a decreasing downstream portion of said wing 3,4 extending from a point where a tangent parallel to said horizontal plane passes to the trailing edge 33. In other words, each fairing 6 is located on the rear part of the upper surface 30,40 of the corresponding wing 3,4.

[0090] According to one embodiment, the craft 1 also includes a fairing 6 similar to that at a junction between the wall 20 of the hull 2 ​​and the upper surface 30, 40 of each of the forward and / or aft wings 30, 40. Such a configuration is notably visible in Figure 6.

[0091] According to one embodiment, said fairing 6 has a convex and rounded aerodynamic profile, extending inclinedly between the extrados 3,4 and the inner wall 51 of each lateral plate 5, and diverging from upstream to downstream to a turning point 60.

[0092] According to a preferred embodiment, the aerodynamic profile of said fairing 6 extends convergently from said point 60 of the cusp to the trailing edge 33,43 of the upper surface 30,40 of the corresponding wing 3,4. In other words, the fairing 6 tapers after the point 60 of the cusp to meet the trailing edge 33,43 of the wing 3,4.

[0093] In a combined mode, the fairing 6 therefore forms a wave or ripple, extending inwards, which comes to cover the wedge or orthogonal junction of the extrados 30,40 with the internal surface of the internal wall 51 of the lateral plate 5.

[0094] Different embodiments of said fairing 6 are shown in figures 6 to 8.

[0095] Such a fairing 6 acts as a wedge flow breaker for the airflow and prevents wedge-shaped uplift of said airflow. In particular, combined with the profile shape of the upper edge 52 of each lateral plate 5, the fairing 6 prevents the vortex sheets channeled outwards by said diverging upper edge 52 from flowing and reaching the inner wall 51 of each lateral plate 5, the upper surface, and the corner where it joins the upper surface 30, 40. Combined with the upper edge 52, the fairing 6 limits shear by smoothly and fluidly guiding the airflow along the various walls. The fairing 6 thus improves the flow of the residual airflow generated by the upper edge 52, guiding it along a specific trajectory to a direction substantially parallel or tangent to the upper surface 30, 40.

Claims

DEMANDS 1. Ground-effect maritime craft (1), of the flying boat type, comprising - at least one hull (2), provided with a horizontal plane (AA 1 extending longitudinally and parallel above a waterline, - a wing forming an aerodynamic lift emerging along said horizontal plane (AA 1 ) and provided with i) 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 extremities connected to said hull (2) and forward distal extremities; ii) at least one pair (4) of rear wings extending symmetrically on either side of the right and left sides of said hull (2), with rear proximal extremities connected to said hull (2) and rear distal extremities; - each rear wing (4) having an aerodynamic profile with an upper surface (extrados) (40) and an upper surface (intrados) connected upstream by a leading edge (42) and downstream by a trailing edge (41); the craft (1) further comprising - lateral plates (5), with an outer wall (50) and an inner wall (51), an upper edge (52) and a lower edge (53), the inner wall (51) of each of the lateral plates (5) connecting the anterior distal end of one of the anterior wings (3) and the posterior distal end of one of the posterior wings (4) located on the same side; characterized in that - the upper edge (52) of each of the said side plates (5) extends in projection above the front wings (3) and the rear wings (4); - said upper edge (52) includes an external profile diverging upwards with respect to the external wall (50) of the plate (2).

2. Maritime craft (1) according to the preceding claim, characterized in that the external profile of the upper edge (52) of each lateral plate (5) has a convex shape of geometric section.

3. Maritime craft (1) according to claim 1, characterized in that said external profile of the upper edge (2) of each side plate has a convex shape of rounded section.

4. Sea craft (1) according to any one of the preceding claims, characterized in that each side plate (5) comprises a front edge (53) extending said upper edge (52) with a similar profile.

5. Sea craft (1) according to any one of the preceding claims, characterized in that said upper edge (52) forms a tube (500) of an elastic material.

6. Maritime craft (1) according to any one of the preceding claims, characterized in that it comprises at a junction between the inner wall of each lateral plate (5) and the extrados (30,40) of each of the front and / or rear wings (3,4), a wedge-shaped flow fairing (6).

7. Maritime craft (1) according to the preceding claim, characterized in that said fairing (6) is located at the level of a decreasing downstream portion of said wing (3,4) extending from a point of passage of a tangent parallel to said horizontal plane to the trailing edge (33,43).

8. Sea craft (1) according to any one of claims 6 or 7, characterized in that said fairing (6) has a convex and rounded aerodynamic profile, extending inclinedly between the extrados (30,40) and the inner wall (51) of each lateral plate (5), diverging from upstream to downstream to a turning point (60).

9. Maritime craft (1) according to the preceding claim, characterized in that the aerodynamic profile of said fairing (6) extends convergently from said turning point (60) to the trailing edge (33,43) of the extrados (30,40) of the corresponding wing (3,4).

10. Sea craft (1) according to any one of the preceding claims, characterized in that each of said side plates (5) extends in projection below the front wings (3) and the rear wings (4).

Images