Ships – Watercraft with means used in providing sailpower
Reexamination Certificate
1999-07-20
2001-04-17
Swinehart, Ed (Department: 3612)
Ships
Watercraft with means used in providing sailpower
C114S039260
Reexamination Certificate
active
06216621
ABSTRACT:
BACKGROUND OF THE INVENTION
Watercraft whose means of developing dynamic lift is entirely from hydrofoils and/or planing elements develop a certain amount of drag from the structure that keeps all of these water and air foils positioned and linked. Furthermore, the performance of a hydrofoil deteriorates near the surface of the water. More extensive use of airfoil surfaces with adequate means of control and adjustment is a possible solution. Where these surfaces have a variable cant relative to the horizontal and fore and aft pivot relative to the lateral plane, trimming and controlling them to develop vertical lift or horizontal drive is analogous to trimming a windsurfer sail.
In addition to the Schweitzer/Drake windsurfer, prior art devices with which the craft of the present invention can be usefully compared and contrasted include the Amick flying boat, the Smith self-launching glider, the Magruder sailing wing and the McIntyre sailplane.
SUMMARY OF THE INVENTION
The wind-powered air/watercraft interface craft includes a fuselage or hull with a pivoting wing and tailplane, canard or secondary tandem wing and port and starboard wing tip amas, hulls, pontoons or floats of which each may have leeboards/centerboards for lateral resistance and forward or aft skegs/trim tabs/rudders, and additional sails or driving surfaces such that the wing and tail/bowplane pivot about one, two or three axes in parallel and the fuselage and leeward amas (or, in the tandem configuration, both amas) remain parallel.
The craft of the present invention, although similar in configuration to an airplane, operates in the interface between air and water, depriving both lift and drive from the relative motion of the two media. Consequently it has more degrees of freedom in the lifting and driving surfaces and trim controls about more axes than would be necessary were the craft operating in a single medium.
The craft of the present invention is a coherent structure composed of lift and drive elements rather than a collection of lift and drive elements strung together with pure drag elements. Some of its features are found, in a comparable but different combination, in the Amick flying boat, the Smith self-launching glider, the Magruder sailing wing and the McIntyre sailplane.
In its first several embodiments, the craft of the present invention is similar in appearance to an aircraft with a high dihedral wing. In a tandem configuration it may, as does the Smith self-launching glider, include an after wing with less dihedral than the forward wing. Like the Magruder sailing wing or the Schweitzer/Drake windsurfer, wings are attached to the fuselage by a joint with one or more axes of rotation. However, the craft of the invention is different from the windsurfer in that the fuselage and wing tip amas pivot under the wings in a parallel disposition such that the roll moments generated by the wings about the fuselage or centerline center of lateral resistance may oppose each other but lift and drive forces complement each other in the configurations shown.
As in the instance of the Amick flying boat, the craft of the present invention in various embodiments is able to roll or pivot about a horizontal longitudinal axis either through the main hull centerboard(s) and center of lateral resistance or through the CLR in the leeward ama/float depending on conditions and specific dihedral of the craft. For example, with a 45° dihedral or perpendicularly disposed port and starboard wings, the craft can rotate about the fuselage CLR, while a craft with a 30° dihedral and maximum drive at 30° roll about the leeward ama can be trimmed to pivot about the leeward ama CLR.
The multiplicity of possible trim adjustments could present a problem of manageability; however, it is anticipated that, for a given course of sail, some of the adjustments can be set and only a few trimmed constantly. In general, variation is through small angles and some are not precisely critical, as is the case with, for example, a keel boat heeled to 30°.
In other embodiments, the craft of the present invention resembles the McIntyre sailplane in either a catamaran or trimaran configuration. It is different in that the cross arms are lifting surfaces, the sails are wing sails and the hulls may have vertically as well as laterally lifting hydrofoil appendages.
The craft of the invention includes means for varying and/or adjusting the incidence angle of the port and starboard wings and tailplanes either together or independently relative to the horizontal plane and to the relative angle of the wind, means for varying and/or adjusting the angle of the centerline of the wing configuration relative to the centerline of the hulls, and means for varying the angle of the wing configuration relative to the vertical, and for varying the incidence angle of the tailplane relative to and independently of that of the main wing configuration.
The craft of the invention may include articulation of any of the wing surfaces in a chordwise direction, so as to vary the surface's lift coefficient independently of its angle of incidence.
Wings to pivot as described are mounted on an axis perpendicular the datum waterline (DWL) of the main (center) hull, a transverse spanwise axis and a longitudinal horizontal axis (which may be the fuselage itself).
On any of the embodiments, wings can be rotated or parallelograms of wings and amas can be skewed by a variety of means or combination of means such as: drum winches and cables, operated manually or by servo motors, or tillers , or steering gears with wheel or joystick or servo motor operation. Similarly, wings can be trimmed about their spanwise axes by a variety of means or combination of means. With the single wing or wing and bow or tailplane configuration, it may be preferable to have each ama pivot about a single axis perpendicular to the plane defined by the chordline and spanwise axis of the wing.
In some embodiments, wings may be mounted on pylons above the fuselage so as to lower the payload and center of gravity of the craft and improve its transverse stability. The length (height) of the pylons may be varied by mechanical means. The weight of the fuselage may be varied by flooding or emptying of water tanks.
Angles of attack of vertically or horizontally lifting hydrofoil surfaces may be varied and foils may be retracted or adjusted in area or extended as the craft fuselage and/or amas are lifted clear of the water's surface. The angle variations are essential in enabling the wings to drive the craft as a sailing boat and provide vertical lift to allow the fuselage to fly clear of the water's surface with only minimal ama and lateral resistance in the water. Hydrofoils/leeboards/centerboards on the fuselage/amas may also be curved or hooked so as to provide optimum horizontal and vertical lift for the given conditions. They may also be compound foils angled or configured to generate lateral and/or vertical force as needed.
Port and starboard wing/tailplanes/bowplanes may have dihedral angles relative to the horizontal of between 0° and 45°, but the dihedral angles of the main wing and the secondary wing/plane do not necessarily have to be the same. The wing dihedral angle of a given craft may be variable by mechanical means for different wind conditions.
The craft may also be designed without the tail/bow plane or secondary wing so that balance and steering are accomplished by trim and pivoting of a single wing. The craft may also have more than two or a multiplicity of port and starboard wing/tail/bow plane/elements.
The wing configuration may also be used in conjunction with wheels for land sailing or ice runners instead of hulls and amas. The port and starboard wing spans may also have a secondary inflection point giving them a double dihedral angle with the amas mounted at those secondary inflection points. A double dihedral would limit the roll angle but might have some structural benefits. The angle between the vertical windward span and the leeward span defines the maximum roll angle.
The
Pillsbury & Winthrop LLP
Swinehart Ed
LandOfFree
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