GB2341371A

GB2341371A - Wind powered vehicle with kite sail

Info

Publication number: GB2341371A
Application number: GB9920478A
Authority: GB
Inventors: John Godfrey Morley
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-08
Filing date: 1999-09-01
Publication date: 2000-03-15
Anticipated expiration: 2019-09-01
Also published as: GB9819522D0; GB2341371B; GB9920478D0

Abstract

A wind powered vehicle comprises a vehicle body 1, a kite sail 4 rotatable about a first axis inclined to the vertical, a support structure for supporting the kite sail about the first axis while allowing it to rotate relative to the vehicle body about a second axis, and rotation means 16A, 16B and 11 to rotate the kite sail about the first axis, to adjust the angle of incidence of the kite relative to the wind. The support structure may comprise a mast 6 and a pair of booms 7 and 8, which rotate relative to the vehicle about the second axis. The second boom may be provided on the opposite side of the mast to the first boom, and may carry the rotation means, in the form of a pivoted bar. A hydraulic control system may be provided to reduce the angle of incidence of the kite sail to the wind, when the force on said sail rises above a predetermined level.

Description

2341371 Wind-Powered Vehicle 5 The present invention relates to a

wind-powered vehicle with a kite sail, i.e. a sail which gives lift in addition to propulsion.

According to the present invention there is provided a wind-powered vehicle comprising a vehicle body, a kite sail rotatable about a first axis inclined to the vertical, a support structure for supporting the kite sail about the first axis, said support structure also allowing said kite sail to rotate relative to the vehicle body about a second axis, and rotation means to rotate the kite sail about the first axis thereby to adjust the angle of incidence of the kite relative to the wind.

Preferably the support structure includes a mast to provide an upper securement point and a boom having an end adjacent the mast and a free end to provide a lower securement point for the sail.

Preferably the boom and/or mast rotates relative to the vehicle to allow the kite to rotate relative to the vehicle about the second axis.

Preferably a second boom is provided which rotates on the opposite side of the mast to said first boom.

Preferably the first and second booms are connected so that one rotates in sympathy with the other..

Preferably the rotation means includes a mechanism mounted on the second boom. Preferably the mechanism includes a bar pivoted substantially at its centre to the second boom and releasably lockable in one of two positions, and said rotation means further includes lines extending from the bar to the kite sail.

Control means may be provided to reduce the angle of incidence on the kite when the vertical lift created by the kite on the vessel increases above a predetermined level. Preferably the control means controls the rotation means of the kite. The control means may be a hydraulic system which is operated by lifting movement of the kite relative to the vehicle body so that when the kite exerts the lift, this lift operates the rotation means.

The support structure may be a mast and boom in the form of a single frame pivoted to the vehicle body.

The frame may be pivoted to the vehicle body by a cylinder on the frame which rotates around a piston connected to the vehicle body. The piston and cylinder body may form part of the said hydraulic system of the control means.

The vehicle may be a sailing vessel.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a first embodiment of a wind-powered vehicle according to the present invention; Figure 2 is an enlarged, part schematic view of Figure 1; Figure 3 is a perspective view of second form of a sail and sail support structure for use in a vehicle according to the present invention; and Figure 4 is a perspective view of a third embodiment of a vehicle according to the present invention.

Referring to Figure 1, there-is-s-hown a wind-powered vehicle having a vehicle body in the form of a boat, specifically a catamaran 1. The catamaran 1 includes a pair of hulls 2A,2B joined by a bridge 2C steered with rudders 3A,3B.

A kite sail 4 is provided in the form of a diamond shape adapted to rotate about its longest axis of symmetry 4A (as shown in dotted lines). A support batten 5 extends across its short axis of symmetry.

A support structure is provided in the form of a single frame which defines a mast 6, a first boom 7 on the opposite side of the mast to a second boom 8, and a cylinder 9. The cylinder 9 rotates about a bearing 10 on the bridge 2C. The support structure can thus rotate relative to the bridge 2C. The first and second booms are connected so that one rotates in sympathy with the other.

The first boom 7 has one end 7A adjacent the mast 6 and 5 a free end 7B. The top of the mast 6 provides an upper securement point for the kite sail, and the free end 7B of the boom provides a lower securement point for the kite sail whereby the kite is supported to rotate about its axis 4A. The support structure supports the kite at an angle of about 45 degrees to the horizontal as shown.

Because the support structure carrying the kite can rotate relative to the bridge 2C so also the kite sail can rotate relative to the boat.

Rotation means is provided to rotate the kite sail about its axis thereby to adjust the angle of incidence of the kite relative to the wind. The rotation means in this embodiment includes a mechanism in the form of control bar 11 pivoted at its centre to the second boom 8 about an axis 12. The control bar is releasably lockable in one of two positions by means of catches 13A,13B mounted on arms 14A,14B. Arms 14A,14B are also pivoted to the boom 8 on common axis 12. A winch 15 on the control bar 11 controls a pair of control lines in the form of rope sheets 16A,16B secured to either end of batten 5. The control bar 11 may have a pivotal axis set at the same angle as the angle of the kite rotational axis so that the bar 11 remains parallel to the batten 5.

In use, operation of the winch pulls the left or right hand side of the batten 5 to adjust the angle of incidence of the kite relative to the wind, and the control bar is 5 secured to an appropriate one of the catches 13A,13B on the control bar depending on which tack the boat is sailing.

As the angle of incidence is increased, so the support structure will rotate until an equilibrium position is reached. Depending on the direction of the wind and the direction of the boat relative to the wind, the angle of incidence can be adjusted to control the speed of the boat. Once the kite angle of incidence is set, the kite will rotate relative to the vehicle to adjust automatically to changes in direction, boat speed and course steered. Heeling forces are substantially eliminated and substantial lifting forces are developed because the sail is inclined to the vertical.

A helmsman may be supported in a seat 17 with foot rests 17A,17B on the end of the second boom 8 to operate the winch 15 and to steer the boat with a tiller 18 connected through cables 19A,19B to the rudders 3A,3B. The weight of the helmsman will help balance the structure and the helmsman's weight will be to at least some extent lifted by the kite.

Control means may be provided to reduce the angle of incidence on the kite when the vertical lift created by the kite on the vessel increases above a predetermined level so that the catamaran does not go out of control, such as lifting out of the water, and so it can respond to gusts of wind. As shown in Figure 2, the cylinder 9 accommodates a hydraulic piston 20 dividing the cylinder into two hydraulic cylinders 20A,20B. The piston 20 is on a piston shaft 21, and the shaft 21 is connected to the bridge 2C by a plate 22 which allows the shaft to rotate but not move vertically.

If the kite imparts an excessive lifting movement to the vehicle body via the support structure, the cylinder 9 will rise forcing hydraulic fluid into a pair of actuators 23A,23B connected to the arms 14A,14B. This rotates the control bar 11 which de-powers the kite. Springs 24A,24B restore the piston 20 into an equilibrium position. The springs also provide some degree of suspension to the booms and hence the helmsman's seat.

If desired the vertical lift of the kite could also be controlled by adjusting the angle of the axis of the kite relative to the horizontal. e.g. by making it more or less than 45 degrees as mentioned above. This could be achieved by adjusting the position of the upper and lower attachment points on the mast and first boom, for example.

The invention may include further features. For example, keels may be provided and these could be variable in size, e.g by means of a lifting keel. Also the angle of incidence of the keel relative to the direction in which the boat is travelling could be changed, e.g. to provide a hydrodynamic lift to windward.

Instead of being on a seat at the end of the second boom 8, 5 the helmsman could be on the bridge 2C.

The support structure could take a form different to that described above. For example the boom could be hinged and thus rotate relative to a mast fixed to the vehicle.

The control lines 16A,16B could be in the form of struts rather than ropes.

The vehicle may further include a hydrovane or other device to impart a downward and backward force on the vehicle to prevent it from lifting up, e.g in a gust of wind. Such a hydrovane could impart a variable force and could be controlled by the control means.

Figure 3 shows a modified form of the sail support structure. In Figure 3, a single boom 7 is used instead of the twin boom arrangement of Figure 1, and the mast structure comprises a single mast 6.

A sail assembly is mounted between the end of the boom 7 and the top of the mast 6 and comprises a support member 32 carrying near each end two pairs of struts 34 and 36, each strut being braced by a wire 35 connected between the strut and the support member 32. A first kite sail 38 is mounted between the pairs of struts 34 and a second sail is mounted between the pairs of struts 36, the two sails being rectangular and parallel.

The support member 32 is rotatable in bearings 42 and 44 at, respectively, the end of the boom 7 and the top of the mast 6. The support member 32 is inclined to the vertical and defines an axis about which the sails 38 and 40 can rotate. Rotation of the sails about this axis is controlled by lines 46 connected between struts in the upper pairs of struts 34 and 36 and a control bar 48.

A weight 50 is attached to an arm 51 secured to the support member 32 to provide a counterweight for the sail assembly when the support member does not pass through the geometric centre of the sail assembly 30. The system can be gravitationally balanced and geometrically arranged so that, when no control restraint is applied, the sails will align themselves parallel to the wind with the boom 7 pointing downwind.

Rotation of the sail assembly in its bearings is achieved by use of the control bar 48 which is pivotally mounted at 52. The lines 46 are attached to the sails near their trailing edges to the rear, or downwind, of the axis of rotation of the sail assembly in the bearings 42 and 44. The control lines 46 pass through fairleads at each end of the control bar 48 and thence to an attachment point 54 on a vertical tubular member 56 the lower part of which is secured to the hull of the boat. The whole sail assembly rotates about this member 56 through a bearing 58.

Rotation of the control bar 48 causes one or other of the control lines 46 to be hauled in thus rotating the sail assembly about the member 32, and the action of the sails is as previously described. The sails feather themselves and the boom 7 rotates to point downwind if the control bar 48 is released.

If the aerodynamic lifting force generated by the sails exceeds the total weight of the sail assembly, then the sail assembly will move up by axial displcement of the bearing 58 on the member 56. This action releases the tension in the control lines 46 alowing the sails to become partially or completely feathered thereby reducing the lifting force.

Figure 4 shows a further embodiment of the present invention in the form of a monohull boat. The support structure for the sail 60 comprises a mast 62, a main boom 64 and an auxiliary boom 66. The main boom 64 is connected to the mast 62 through a bearing 68 which allows the boom 64 to pivot round the mast 62, while the auxiliary boom 66 is mounted on a bearing 70 which can slide along the main boom 64.

The sail 60 is secured at its foot to the auxiliary boom 66 while its head is secured to a rotary bearing 72 on the mast. A first control line 74 controls the position of the bearing 70 along the boom 64 and hence the angle of inclination of the axis of the sail, a second control line 76 braces the boom and controls the angle of the boom 64 relative to the horizontal, and a third control line 78 controls the angle of the auxiliary boom 66 relative to the main boom 64. If desired, a counterweight could be provided on the end of the boom 66 to balance the weight of the sail 60 and the boom 66.

With this embodiment, in light weather, for example, the bearing 70 may be brought close into the mast and the sail then functions as a conventional fore and aft sail. Also in this embodiment a second sail may be mounted further along the main boom.

In this third embodiment the auxiliary boom serves the same function as the batten 5 in Figure 1, i.e. to secure control lines for controlling the angle of incidence of the sail.

The vehicle could be other than a boat such as a land yacht, or indeed a model.

1 1 1 1 '

Claims

CLAIMS. 5

A wind-powered vehicle comprising a vehicle body, a kite sail rotatable about a first axis inclined to the vertical, a support structure for supporting the kite sail about the first axis, said support structure also allowing said kite sail to rotate relative to the vehicle body about a second axis, and rotation means to rotate the kite sail about the first axis thereby to adjust the angle of incidence of the kite relative to the wind.
2. A vehicle as claimed in claim 1, in which the support structure includes a mast to provide an upper securement point and a boom having an end adjacent the mast and a free end to provide a lower securement point.
3. A vehicle as claimed in claim 2, in which the boom, or the boom and mast, rotates relative to the vehicle to allow the kite to rotate relative to the vehicle about the second axis.
4. A vehicle as claimed in claim 3, in which a second boom is provided which rotates on the opposite side of the mast to said first boom.
5. A vehicle as claimed in claim 4, in which the first and second boons are connected so that one rotates in sympathy with the other.
6. A vehicle as claimed in claim 5, in which the rotation 5 means includes a mechanism mounted on the second boom.
7. A vehicle as claimed in claim 6, in which the mechanism includes a bar pivoted substantially at its centre to the second boom and releasably lockable in one of two positions, and said rotation means further includes lines extending from the bar to the kite sail.
8. A vehicle as claimed in any preceding claim, in which control means are provided to reduce the angle of incidence on the kite when the vertical lift created by the kite on the vessel increases above a predetermined level.
9. A vehicle as claimed in claim 8, in which the control means controls the rotation means of the kite.
10. A vehicle as claimed in claim 8 or claim 9, in which the control means is a hydraulic system which is operated by lifting movement of the kite relative to the vehicle body so that when the kite exerts the lift, this lift operates the rotation means.
11. A vehicle as claimed in any of claims 2 to 10, in which the support structure is a mast and boom in the form of a single frame pivoted to the vehicle body.
12. A vehicle as claimed in claim 11, in which the frame is pivoted to the vehicle body by a cylinder on the frame which rotates around a piston connected to the vehicle body.
13. A vehicle as claimed in claim 12, in which the piston and cylinder body may form part of the said hydraulic system of the control means.
14. A vehicle as claimed in any preceding claim, and having at least one hull.
15. A vehicle as claimed in any of claims 2 to 5, in which the support structure includes a sail supporting member extending between rotary bearings on the first boom and the mast.
16. A vehicle as claimed in claim 15, in which the support member carries two parallel sails.
17. A vehicle as claimed in claim 2 or claim 3, in which the boom is rotatable in a bearing on the mast, and an auxiliary boom is mounted on a slide bearing on the first boom, a sail being secured between the auxiliary boom and the mast.
18. A wind-powered vehicle substantially as hereinbefore described with reference to and as shown in the accompanying drawings.