Wing In Ground Effect Hydrofoil Vessel

Abstract

The present invention concerns a marine vehicle that derives its lift and control forces and moments from a combination of the following mechanisms; aerodynamic effects on a lifting surface in ground effect, hydrodynamic effects on submerged hydrofoils, planing forces on deployed winglets, and hydrostatic effects on submerged elements. The portion of the overall lift and control forces that is contributed by each mechanism varies as a function of vessel speed. The hydrofoils may be subcavitating, supercavitating, transcavitating or superventilated. The three lift and control mechanisms are individually found on existing Wing-In-Ground Effect (WIG) vehicles, hydrofoil vessels, and multi-hull vessels but have not previously been combined in the manner described. The present invention combines these three elements to achieve high lift-to-drag ratios, low fuel consumption, good maneuverability, low noise, low vessel draft, low vessel motions, and operation in higher sea states at all relative headings to the wind and waves. Applications of this craft include both civilian and military uses.

Description

The elements of this invention include an aerodynamic lifting surface operating in ground effect, two or more hydrofoil surfaces generating lift and control forces below the water surface, and downwardly deployable winglets that allow a marine vessel to transform between a WIG-hydrofoil to a catamaran vessel as the vessel's speed is changed. The position of the winglets may be continuously varied to change the clearance between the wingtips and the water surface, thereby changing the lift coefficient of the wing in ground effect. The craft has movable flaps at the trailing edges of both the aerodynamic and hydrofoil lifting surfaces. The craft may be propelled with either an in-water propeller or an in-air propeller. The combination of lift and control mechanisms enables the vehicle to achieve high lift-to-drag ratios over a wide range of operating speeds in the presence of waves. Unfamiliar terms used in this document are defined in List 1

Term                   Definition
Wing In Ground Effect  An air vehicle that experiences enhanced
Vehicle (WIG)          lift and improved lift-to-drag ratio as a
                       result of operation within one chord
                       length of a fixed surface. The effect is
                       characterized by an increased pressure
                       on the bottom of the lifting surface.
Air Cushion Vehicle    A vehicle that has a flexible skirt that
(ACV)                  forms a cavity beneath the vehicle.
                       Pressurized air is pumped into the cavity
                       to spread the vehicle weight over a large
                       footprint.
Surface Effect Vehicle A vehicle that has two or more rigid hulls
(SES)                  in the water that, in conjunction with
                       forward and aft skirts, form a
                       pressurized cavity that can spread the
                       vehicle weight over a large footprint.
Hydroplane             A vehicle that obtains both aerodynamic
                       and planing lift. The planing lift is
                       obtained from one or more hulls that
                       remain in contact with the water surface.
                       The aerodynamic lift is obtained from a
                       wing that joins the hulls or extends
                       beyond the hull(s).
Subcavitating          A hydrofoil on which the pressure on the
                       upper surface does not go below the
                       vapor pressure of water and where no
                       cavitation occurs.
Supercavitating        A hydrofoil designed to allow the
                       pressure to drop below vapor pressure
                       with a cavity forming adjacent to the
                       surface of the foil.
Superventilated        A hydrofoil designed to inject or vent air
hydrofoil              into a low pressure cavity on the upper
                       surface of the foil thereby reducing drag
                       on the foil and enabling the foil to be
                       free of cavitation damage at high
                       speeds.
Transcavitating        A foil that has deployable appendages or
                       elements that effectively change the
                       hydrodynamic shape to allow a transition
                       from subcavitating to supercavitating
                       regimes.
Lift-To-Drag Ratio     A measure of the vehicle's efficiency that
                       is obtained by dividing the total lift
                       (under static conditions, this is the
                       vehicle weight) by the drag when
                       operating at speed.

FIG. 1 is a perspective view of the marine vehicle with the winglets 20 in the horizontal position as they would be at vehicle speeds of twenty knots or more. Shown in this figure are the controllable hydrofoils 21 mounted on struts 24 and the main body of the hull 22. Aerodynamic flaps 23, located at the aft end of the main body, are used to control the aerodynamic lift generated by the flow of air over the hull. In this variant, a main in-water propeller 25 is located behind the aft strut where it is driven by an inclined shaft.

FIG. 2 is a perspective view of the marine vehicle with the winglets 20 in the vertical position as they would be at speeds below about twenty knots. In this condition, the winglets 20 provide the buoyancy to support the vehicle weight. There is a hinge line 26 at the junction of the winglet and the main body of the hull. This hinge line is the line about which the winglets pivot from their horizontal position to their vertical position.

FIG. 3 is a side view of the marine vehicle with the winglets 20 in the vertical position as they would be at speeds below about twenty knots. The winglets 20 contain auxiliary propulsors 27 and are fitted with rudders 28 for low speed maneuvering. The winglet hinge line 26 is again shown.

FIG. 4 is a perspective view of the marine vehicle with the winglets 20 in the partially raised position as they would be during the transition from hull-borne to foil-borne operation. The tips of the winglets 20 are fitted with two or more planing surfaces with chines 27 to generate planing lift during the time when these winglets are in the water. In this condition, the winglets 20 inhibit the circulation of air laterally around the wing tips thereby increasing the pressure beneath the aerodynamic surfaces of the main body 22.

FIG. 5 shows an inclined shaft 28 propulsion system fitted with one or more in-water propellers 25.

FIG. 6 shows an in-air propulsion system with a puller propeller 31.

FIG. 7 shows an in-air propulsion system with a pusher propeller 32.

FIG. 8 shows the winglet flaps 25 that were previously described as low-speed rudders, now providing aileron functions when the vehicle has transitioned to high speed operation and the deployable winglets have rotated into the horizontal position. FIG. 8 also shows vertical control surfaces 33 to provide yaw control. FIG. 8 shows both in-air and in-water propellers although any one vehicle would normally have only one main propulsion system.

FIG. 9 is a representation of the changes in lift and control forces and moments as a function of vehicle speed.

Description of the Prior Art

Lake was granted U.S. Pat. No. 1,307,135 for a seaplane float that included a combination of hydrostatic and hydrodynamic features to reduce friction and cushion the impact of a hydroplane float during landing and takeoff. This invention included a means for injecting air between transverse aquafoils that are embedded in the float. The patent is relevant in that it is an early invention that combines three lift mechanisms operating in concert at the air-sea boundary. The particular combination includes hydrostatic lift (buoyant floats), pressurized air cavity lift (exhaust gas injected between the aquafoils), and hydrodynamic lift (aquafoils).

Dickenson et al. were issued U.S. Pat. No. 2,343,645 for a folding wing that was designed to accommodate the particular needs of a seaplane. The invention is relevant to the present invention to the extent that it specifically accommodated buoyant floats on a movable wing that was designed to withstand structural loads at all positions.

La Fleur was granted U.S. Pat. No. 3,064,370 for a dredge with buoyant cylindrical sponsons that could be moved vertically on hinged arms to change the draft of the floating vessel. This invention described the concept of deployable buoyancy on rotating arms that provided the vessel with shallow draft, variable beam, and high transverse waterplane inertia. The patent is relevant in that it establishes the art of vertically deploying buoyancy about a swinging arm at the sides of a marine vessel.

Mathews was granted U.S. Pat. No. 3,485,198 for a boat with deployable flotation sponsons. Like La Fleur, this invention allows variations in draft, beam, and waterplane inertia. This patent extends the art to include variable planing surface area and new deployment mechanisms.

Austin was granted U.S. Pat. No. 3,918,382 for a twin-hull marine vessel that combined lift from aerodynamic surfaces with lift from planing surfaces. The aerodynamic lift is derived from an airfoil that bridges between catamaran hulls. This invention included a flap on the trailing edge of the airfoil that was used to close the aft end of the cavity formed between the catamaran hulls thereby increasing the lift of the airfoil due to a higher pressure on the under side of the foil. Along with other ground-effect patents (e.g., Weston, U.S. Pat. No. 3,952,678) with different hull configurations, the art of combined hydrostatic, planing, and aerodynamic lift was recorded.

Westfall was granted U.S. Pat. No. 4,237,810 for a boat that combined hydrodynamic and aerodynamic lift. Although similar to other multi-hull hydroplanes described earlier, this invention included skis that augmented the lift force provided by the aerodynamic surfaces. There are no aerodynamic lifting surfaces in this patent.

Daniel was granted U.S. Pat. No. 4,452,166 for a foil stabilized monohull. Like La Fleur and Matthews, this invention used deployable buoyancy to control the draft and stability of a marine vessel. This patent is relevant in its addition of foil stabilizers to maintain vessel stability once the outboard buoyancy is retracted. These foils were not intended to produce vessel lift but rather to stabilize the hull.

Genfan was granted U.S. Pat. No. 4,964,357 for a planing boat that had moveable aerodynamic wings in ground effect, a fixed hydrofoil located forward, and buoyant sponsons on the tips of the wings. The invention is relevant to the extent that it incorporated movable aerodynamic surfaces, including buoyant pods, from a planing hull that gets additional lift from a hydrofoil mounted beneath the forward end of the hull. The buoyant pods do not generate aerodynamic lift.

Rorabaugh et al. were granted U.S. Pat. No. 5,544,607 for movable sponsons on a hydrofoil watercraft. While earlier patents had established the art of deployable buoyancy for enhanced stability and draft control, Rorabaugh extended this art to the particular application of a pure hydrofoil craft. The deployable sponsons of Rorabaugh do not generate aerodynamic lift.

Roccotelli was granted U.S. Pat. No. 5,813,358 for a trimaran vessel that incorporated a wing in ground effect that is located above the three hydrostatic (trimaran) hulls, and three struts that included submerged foils used for vessel stabilization and propulsion. This invention had retractable winglets that pivoted vertically up. The invention is relevant in that it combined the aerodynamic lift of a wing in ground effect with the hydrostatic lift of a trimaran hull and the stabilizing effect of submerged foils. This invention did not envision shared lift between the hydrofoils and the wing.

Jacobson was granted U.S. Pat. No. 6,014,940 for a seaplane that operates in ground effect. The patent is relevant to the extent that it envisions a combination of planing and aerodynamic lift in a craft that operates in ground effect. Like the subject of this patent, the invention uses a thick wing section to achieve high levels of lift in close proximity to the water surface. Although the invention has retractable winglets, these retract vertically upwards to minimize vessel beam when stowed. The invention does not describe hydrofoil lifting surfaces.

Magazzu' was awarded U.S. Pat. No. 4,955,312 for a controlled geometry hydrofoil vessel. This craft embodies a variable-geometry deployable hydrofoil arrangement that is relevant to the extent that it provides a variation in the lift surface geometry as a function of speed. The invention does not use aerodynamic lift.

Burg was granted U.S. Pat. No. 6,199,496 for a hybrid air-cushion ground-effect vehicle. This invention uses a pressurized cavity between hydrostatic hulls to generate an air cushion, has winglets that operate in ground effect, and uses a submerged retractable foil to stabilize the vessel. Unlike the present invention, this craft is a surface effect vehicle that derives its primary lift by pumping high pressure gas into a cavity beneath the hull.

Fischer and Matjasic were awarded U.S. Pat. No. 6,230,835 B1 for a ground effect vehicle. The invention claims a series of aerodynamic improvements that result from coupled operation of vertically-articulated winglets and wing flaps. The patent is relevant in that it cites resiliently mounted winglets that mitigate the structural loads associated with winglet immersion in the water at speed.

Burg was granted a second U.S. Pat. No. 6,546,886 B2, in which he expanded his claims relative to surface effect multihull vehicles that receive additional aerodynamic support from retractable winglets. These winglets retract vertically and do not provide buoyancy.

Markie was awarded U.S. Pat. No. 6,990,918 B2 for a marine vessel with upwardly retractable winglets that provide aerodynamic lift in ground effect when they are deployed in a horizontal position. This invention does not include hydrofoil lift and the winglets are retracted vertically upward.

SUMMARY OF THE INVENTION

The invention uses a combination of lift mechanisms to achieve high lift-to-drag ratios, low motions, good propulsion efficiency, and useful internal volume through wide ranges of vehicle speed, relative wind conditions, and wave conditions. Furthermore, the vehicle has deployable winglets that enable it to maintain a relatively shallow draft at all speeds. The invention seeks reduced fuel consumption in high-speed marine vehicles that have shallow draft. The hybrid combination of lift mechanisms (aerodynamic, hydrodynamic, and hydrostatic) also provide a high level of control authority that is necessary to actively reduce the motions of the vessel throughout the operating speed range thereby reducing the marine vehicle's motions in waves. The combination of Wing-In-Ground effect (WIG) and hydrofoil lift at the higher operating speeds, provides a high lift-to-drag ratio thereby reducing the installed engine power and fuel consumption.

Claims

1. A marine vehicle that has two force-generating elements that work in concert to provide lift and control forces across a broad range of operating conditions, said force generating elements being: an aerodynamic wing operating in ground effect, and one or more hydrofoils operating at or beneath the water surface.

2. The marine vehicle described in claim 1 fitted with subcavitating foils.

3. The marine vehicle described in claim 1 fitted with supercavitating foils.

4. The marine vehicle described in claim 1 fitted with transcavitating foils.

5. The marine vehicle described in claim 1 that is propelled with one or more in-water propellers.

6. The marine vehicle described in claim 1 that is propelled by one or more waterjets.

7. The marine vehicle described in claim 1 that is propelled with an in-air propeller.

8. The marine vehicle described in claim 1 that is propelled with an in-air ducted fan.

9. The marine vehicle described in claim 1 that progressively transitions from a speed regime where the majority of the lift is generated by the hydrofoils to a regime where the majority of the lift is generated by aerodynamic surfaces.

10. The marine vehicle described in claim 1 that is in a speed regime where the primary lift force is generated aerodynamically but the vehicle control forces are generated hydrodynamically by the controllable hydrofoils.

11. The marine vehicle described in claim 1 where the aerodynamic lifting surface is of sufficient thickness to house people and or materials during marine transport.

12. The marine vehicle described in claim 1 that has horizontal and vertical aerodynamic control surfaces to generate yaw forces and to bias the port/starboard lift percentages as may be necessary to operate in cross-wind conditions.

13. The marine vehicle described in claim 1 that has flaps on the trailing edges of the aerodynamic surfaces that are employed to control the gap between the aerodynamic surface and the sea surface, thereby controlling the lift generated from the aerodynamic surface. Said flaps are mechanically actuated and may have resilient elements to avoid structural damage upon wave impact.

14. The marine vehicle described in claim 1 that has aerodynamic and hydrodynamic lift and control forces developed in-air and in-water under the control of algorithms that optimize vehicle lift-to-drag ratio and stability as a function of vehicle speed, relative wind, vehicle load, vehicle center of gravity, sea wave spectra.

15. The marine vehicle described in claim 1 that may have a surface that reduces its radar cross section.

16. A marine vehicle that has deployable winglets to provide aerodynamic lift and control forces as well has hydrodynamic planing forces and hydrostatic buoyant forces. When in the horizontal position, the winglets generate aerodynamic lift and control forces. When rotated downward, the winglets form hydrodynamic planing surfaces and hydrostatic buoyancy. When deployed downward, the winglets transform the outward extents of the aerodynamic surfaces into one or more buoyant hulls that provide planing lift and buoyancy to support the craft at low and zero speeds while achieving low vessel motions and while avoiding the need to retract other propulsion, lift or control appendages to achieve shallow draft.

17. The marine vehicle described in claim 16 that transitions from low-speed hull-borne operation to high-speed operation by raising the winglets from a downward vertical position to a horizontal position as the speed of the vehicle increases and the combined lift of the aerodynamic and or hydrofoil surfaces is equal to or greater than the vehicle weight.

18. The marine vehicle described in claim 16 that has control algorithms provide real-time vehicle control by commanding the coordinated actuation of control surfaces that are located in the air and in the water. The control algorithms vary as a function of vehicle speed to obtain robust control characteristics throughout the speed range.

19. The marine vehicle described in claim 16 that is fitted with low-speed propulsion systems in the deployable winglets thereby minimizing the need to operate high-power propulsion systems during low speed and loiter operations.

20. The marine vehicle described in claim 16 that uses the control flaps on the aft surfaces of the deployable winglets as both in-air ailerons and in-water rudders depending upon the position of the deployable winglets.

21. A marine vehicle that has three mechanisms to generate lift and control forces, said mechanisms being: aerodynamic lift from a wing operating in ground effect, hydrodynamic lift generated from one or more hydrofoils, and buoyant and or planing lift generated by downwardly deployable winglets whose position can be infinitely varied from horizontal to vertical. When in the horizontal position, the winglets generate aerodynamic lift and control forces. When rotated downward, the winglets form hydrodynamic planing surfaces and hydrostatic buoyancy. When deployed downward, the winglets transform the outward extents of the aerodynamic surfaces into one or more buoyant hulls that provide planing lift and buoyancy to support the craft at low and zero speeds while achieving low vessel motions and while avoiding the need to retract other propulsion, lift or control appendages to achieve shallow draft.

22. The marine vehicle described in claim 21 fitted with subcavitating foils.

23. The marine vehicle described in claim 21 fitted with supercavitating foils.

24. The marine vehicle described in claim 21 fitted with transcavitating foils.

25. The marine vehicle described in claim 21 that is propelled with one or more in-water propellers.

26. The marine vehicle described in claim 21 that is propelled by one or more waterjets.

27. The marine vehicle described in claim 21 that is propelled with an in-air propeller.

28. The marine vehicle described in claim 21 that is propelled with an in-air ducted fan.

29. The marine vehicle described in claim 21 that, as speed is increased, undergoes a progressive transition from the majority of the lift being generated by hydrofoils, to the majority of the lift being generated by aerodynamic surfaces.

30. The marine vehicle described in claim 29 that is in a speed regime where the primary lift force is generated aerodynamically but the vehicle control forces are generated hydrodynamically by the controllable hydrofoils.

31. The marine vehicle described in claim 21 where the aerodynamic lifting surface is of sufficient thickness to house people and or materials during marine transport.

32. The marine vehicle described in claim 21 that has horizontal and vertical aerodynamic control surfaces to generate yaw forces and to bias the port/starboard lift percentages as may be necessary to operate in cross-wind conditions.

33. The marine vehicle described in claim 21 that has flaps on the trailing edges of the aerodynamic surfaces that are employed to control the gap between the aerodynamic surface and the sea surface, thereby controlling the lift generated from the aerodynamic surface. Said flaps are mechanically actuated and may have resilient elements to avoid structural damage upon wave impact.

34. The marine vehicle described in claim 21 that has aerodynamic and hydrodynamic lift and control forces developed in-air and in-water under the control of algorithms that optimize vehicle lift-to-drag ratio and stability as a function of vehicle speed, relative wind, vehicle load, vehicle center of gravity, sea wave spectra.

35. The marine vehicle described in claim 21 that may have a surface that reduces its radar cross section.

36. The marine vehicle described in claim 21 that transitions from low-speed hull-borne operation to high-speed operation by raising the winglets from a downward vertical position to a horizontal position as the speed of the vehicle increases and the combined lift of the aerodynamic and or hydrofoil surfaces is equal to or greater than the vehicle weight.

37. The marine vehicle described in claim 21 that is fitted with low-speed propulsion systems in the deployable winglets thereby minimizing the need to operate high-power propulsion systems during low speed and loiter operations.

38. The marine vehicle described in claim 21 that uses the control flaps on the aft surfaces of the deployable winglets as both in-air ailerons and in-water rudders depending upon the position of the deployable winglets.