WO1999059866A1

WO1999059866A1 - An improved kite

Info

Publication number: WO1999059866A1
Application number: PCT/NZ1999/000060
Authority: WO
Inventors: Peter Robert Lynn
Original assignee: Peter Robert Lynn
Priority date: 1998-05-19
Filing date: 1999-05-19
Publication date: 1999-11-25
Also published as: GB2355210B; GB0030977D0; WO1999059866B1; AU4296199A; GB2355210A

Abstract

The kite employs a flexible leading edge (11) with one or more spines (12, 13) orientated substantially parallel to the longitudinal axis of symmetry of the kite. The spines (12, 13) may be in a number of constructions but substantially all constructions provide a shape so as to assist in producing camber in the kite skin. The kite may include either flexible or rigid bridling with a number of attachment points of the leading edge (11) and spines (12, 13).

Description

AN IMPROVED KITE

Field of the Invention

The present invention relates to kites. More particularly, although not exclusively, the present invention relates to kites that are particularly adapted for use in traction kiting. Traction kiting involves the use of kites as sails to provide motive force. Applications include kite buggies, kite sailing boats, surfboards, wave skis, kayaks, snow skis, water skis and similar devices. The present invention may, of course, be used for activities other than traction kiting.

Background to the Invention

The following discussion and description will be provided in the context of kites that are suitable for use in traction kiting. However, this application is not intended to be limiting. The improved kite design, according to the present invention, may of course be used in other flying situations.

Kite designs may be broadly characterised according to their construction. The range of construction covers a fairly broad spectrum ranging from unframed single skin types to single skin framed kites. This frame generally supports and gives shape to the kite's skin. Of course, there exist other designs including ram air and fully rigid kites and combinations of these two.

An example -of unframed single skin types of kite construction mentioned above is the NASA wing design. A further example includes directional, but not ram air, parachutes. An example of the latter type is a delta frame stunt kite.

The NASA wing design is characterised by a generally delta shaped skin (when viewed in plan) which is completely unsupported (i.e.; does not use any spars, cross members or similar rigid structural members). The original NASA wing concept was developed as a parachute-style device that was capable of being steered and functioned as a lifting surface. The shape of the skin was maintained by means of a relatively complex bridling arrangement in conjunction with differential pressure regions across the skin.

It is known to use such NASA wing-type kite designs in the context of traction kiting. However, these designs are typically characterised by an unsupported leading edge that is secured by an array of bridle attachment points along the leading edge. This results in generally poor aerodynamic characteristics due to the inefficient leading edge with high parasitic drag and the necessity that they be bridled at a high angle of attack to minimise the risk of canopy collapse. The large number of bridle attachment points is so that when a positive pressure is created under the skin, the skin "inflates" and holds form chord-wise and span-wise as a result of positive pressure, stresses in the skin fabric and forces transmitted through the bridling.

At the other end of the construction spectrum, there are kites, which incorporate substantial rigid supporting structure. This rigid structure in conjunction with an appropriately shaped skin is designed to create the form and shape of the kite substantially independently of the effects of positive pressure under the skin. In the context of traction kiting, kites of this form typically incorporate rigid leading edges and span-wise cross members attached to points on the leading edge of the kite. Such cross members are designed to limit span-wise deflection of the kite when the kite is under pressure and operating as an airfoil.

A further variation on such framed kite designs includes those that include a highly loaded leading edge member and perhaps a single spine running centrally along the chord of the kite skin. The bridling of such kites is typically attached at a number of points on the leading edge and perhaps to the spine. The primary functions of the leading edge spar are to provide a clean leading edge and sustain the shape of the kite. In such constructions, as the pressure differential above and below the kite skin and the span-wise compressive forces increase, the leading edge spar needs to be sufficiently strong to resist the span-wise bending forces and thus preserve the shape of the kite and its aerodynamic characteristics. Therefore, typically the leading edge of such a kite needs to be a substantial, spar-like member with considerable strength and rigidity. The ends of the dorsal spines (if present) may be used to provide additional bridle attachment points, particularly in two line kites. A significant disadvantage inherent in kite constructions of this type is that the leading edge spar needs to be extremely rigid. This can result in large leading edge spar dimensions, which carries a weight penalty and cause the kites centre of mass to be undesirably located (i.e. too far forward). A further major disadvantage is that rigid framed kites can present a danger to spectators and adjacent kite fliers. As a result of such rigidity requirements, it is common to use high modulus composite materials or similar in order to provide the required weight/rigidity trade-off. The use of such materials involves added expense as well as constructional complexity. Further, single skin flexible framed kites, being the subject of this application, have a significant price advantage over existing ram air traction kites as less material is required in their manufacture.

A further type of kite that may be used in the context of traction kiting are those which use a ram air structure with the addition of rigid leading edge spars. Such kite designs incorporate canopies that have leading edge vents that channel air into internal cavities to produce a ram air inflated fabric structure having an airfoil cross-section. However, again the force and rigidity constraints involved in the use of such kites require spars with a higher level of inherent rigidity with the attendant problems associated with such constructions.

It is an object of the present invention to provide an improved kite design that incorporates aspects of kite designs from different parts of the constructional spectrum in order to overcome and/or mitigate at least some of the abovementioned problems. It is a further object of the present invention to provide an improved kite design which exhibits desirable performance and handling characteristics and is less expensive to produce than prior art kites. It is a further object of the present invention to provide the public with a useful choice.

Disclosure of the Invention

In one aspect the present invention provides for an improved kite including: a kite skin having a leading edge and a trailing edge; a flexible leading edge member which is small in proportion to the maximum chord of the kite; and one or more flexible spines attached to the skin, substantially over their entire length, wherein span-wise rigidity of the kite is provided substantially by components of pressure differential across the skin of the kite acting in substantially span-wise directions, in conjunction with interaction with bridling attached to the flexible leading edge member and at least two of the spine(s).

Preferably, the leading edge members and/or the spines are adapted to be sufficiently flexible that the entire assembled kite can be packed in a coiled form.

The spines may comprise primary spines traversing the centre of the skin from the leading edge to the trailing edge, and secondary spines running from a point on the skin behind the leading edge to the trailing edge.

The spines may be oriented substantially parallel with the longitudinal axis of symmetry of the kite.

The kite may further include a bridling system connected to a plurality of connection points along the leading edge and a plurality of connection points along the length of the spines.

Optionally, the connection points along the spines may include a connection point at the junction of the spine and the leading edge (for primary spines), or at a point on the spine (for secondary spines) and the junction of the spine and the trailing edge, along with one or more-connection points between the forward end of the spine and trailing edge junction.

The bridling arrangement may be in a form adapted for control of the kite by means of two, three or four lines.

The kite skin may be shaped so that camber is provided.

The skin may include foam sections located behind the leading edge. In an alternative embodiment, the kite skin may be manufactured from foam, preferably the foam being laminated to or between one or more fabric layers.

Alternatively, the skin may have panels constructed incorporating foam and/or panels constructed from fabric.

The foam may be expanded polyethylene foam or similar material which exhibits the required degree of floatation.

The camber may be provided by incorporating insert panels that increase the area of skin in a region immediately behind the leading edge.

In a preferred embodiment the kite skin incorporates, when viewed in plan, a curved leading edge and a substantially straight trailing edge, a scalloped trailing edge or similar.

In an alternative embodiment, the spines may be shaped to assist in providing camber in the kite skin.

In an alternative embodiment, the flexible leading edge member may comprise two or more flexible sub-members in a bundle and located in, preferably a sleeve, at the leading edge of the kite.

In yet a further embodiment, the leading edge member may be collapsible, preferably by means of one or more hinges located at the junction of the leading edge and the spines.

The hinges may be in the form of a hinge and pin type arrangement.

In an alternative embodiment, the spines may include built-in reflex, preferably produced by constructing the spine from a combination of materials.

Preferably the spines are constructed in a composite form with a metal forward section and a fibreglass, carbon fibre or similar rear section. The rear section of the spines may incorporate built-in reflex.

In yet an alternative embodiment, the spines may be joined to the kite skin by means of a fabric rib or web lattice or open weave fabric, or foam or part foam section.

Preferably, the fabric rib extends below the kite skin whereby the fabric rib is adapted to receive the spine so that when a pressure differential exists between the upper and lower surface of the kite skin, spanwise movement of air substantially immediately under the kite skin is reduced or substantially prevented.

in yet an alternative embodiment, the spines may be constructed in two parts, an upper and a lower part, wherein the upper part has the shape of an airfoil and the lower part has either a generally linear shape or is curved.

Preferably, the upper and lower parts are of different length with the upper part extending from a point proximate the leading edge of the spine to a point between the leading and trailing edge of the resulting spine whereby the upper part is shorter than the lower part and is joined to the lower part so that an airfoil shape is produced between the upper and front portion of the lower part.

In an alternative embodiment, some or all of the bridles may be in the form of rigid bridles.

Brief Description of the Drawings

The present invention will now be described by way of example only and with reference to the drawings in which:

Figure 1 illustrates a partial bridling arrangement of a hybrid kite;

Figure 2 illustrates a partial bridling arrangement of a hybrid kite; Figure 3 illustrates a partial bridling arrangement of a hybrid kite;

Figure 4 illustrates a plan view of preferred embodiment of the hybrid kite;

Figures 5a-c illustrates embodiments of spine constructions; and

Figure 6 illustrates an underside view of a kite skin with fabric ribs. As noted above, the present invention will be described in the context of traction kiting. More specifically, applications in the context of traction kiting include kite-driven buggies, wave skis, surf skis, kayaks and the like (hereafter referred to kite-driven vehicles). This application is not intended to be limiting as the improved kite design may be used in both static and dynamic context.

Referring to figures 1 -3, partial bridling arrangements are shown for clarity. In practice, the improved kite would incorporate all of the bridling shown on figures 1 , 2, and 3.

To reduce the risk of bridle tangling, some or all of the bridle arrangement may be constructed in the form of rigid bridling. Such an embodiment may use rigid or semi-rigid bridle portions.

As noted in the background to the invention, the spectrum of traction kite design ranges from fully unstructured NASA wing kite designs to rigid framed single skin kites and completely ram air prior art kite designs. The NASA wing design relies on positive under-skin pressure causing the kite skin (or parachute depending on the context) to maintain its shape. In contrast, the fully rigid and supported kite design use extremely rigid members which force the kites skin to retain a particular shape and aerofoil shape.

The improved kite, according to the present invention, may be viewed as a hybrid or intermediate kite construction that draws desirable features from different ends of the kite construction spectrum. More specifically, the NASA wing features of the present invention are the total lack of a rigid leading edge spar and a number of bridle attachment points distributed over the kite skin area. The present invention differs significantly -from known internally structured kite designs in that the leading edge spar of the present novel kite is relatively flexible and does not contribute significantly to the span-wise rigidity of the kite. In contrast, prior art kite designs incorporating either a single leading edge spar or a leading edge spar in combination with cross spars must be capable of withstanding large forces involved in retaining the span-wise rigidity of the kite.

The present invention seeks to obtain a balance between these two contrasting kite construction philosophies. It does so by employing a very flexible leading edge spar that is subjected to relatively low loads when the kite is in flight notwithstanding that this spar can be highly stressed. Coupled with this flexible leading edge spar are spines, the operation of which are described as follows.

Referring to figure 4, a plan view of a kite constructed according to the present invention is shown. The kite 10 includes a skin made up of panels 14a,b, 1 5a,b, 1 6a,b and tip panels as shown. In the particular embodiment illustrated, the leading edge panels 1 6a and b are further subdivided by means of seam taper which provide camber resulting in an aerofoil-like shape when the kite is flying.

In situations where the kite is to be used for water based activities such as kite surfing etc, it is has previously been a problem that prior art kites sink and are therefore difficult to launch when the user is in the water. To assist in overcoming this difficulty, the kite skin may incorporate floatation inserts or panel sections located behind the leading edge in the area indicated by the numeral 800. Of course because the kite sail is symmetrical around its axis of flight, mirror image floatation portions would be located on the other side of the main spine.

These flotation inserts or portions may be in the form of expanded polyethylene or similar type of floating, closed cell, material. The floatation portions may, in some configurations, be located at the tips of the kite skin in the area indicated by the numeral 801 in Figure 1 .

To provide additional floatation, it is envisaged that an alternative form of construction could employ a kite skin formed either completely or partially from a low density material. This skin material may be laminated to, or between, fabric layers to provide additional strength. An alternative construction may include some panels formed from foam or a foam/fabric composite, and/or some panels solely from fabric.

A spine 13 runs from the leading edge 1 1 to the trailing edge 80. Further spines 12a and 12b also run from the leading edge 1 1 to the trailing edge 80 and are located approximately halfway between the primary spine and the tip. Two types of spine are envisaged: primary and secondary (not shown). A primary spine is one that runs across the whole chord of the wing while a secondary spine runs from a point behind the leading edge to the trailing edge - i.e. partial chord-wise coverage. In the latter case, the secondary spines are superficially similar to battens. However, they are bridled in accordance with the present invention. A further possible variation is that the spines may be shaped in an airfoil shape so as to assist in producing camber in the kite skin.

Referring to figures 5a-c, spines may be constructed as shown to overcome a number of problems inherent in prior art kite constructions. With reference to figure 5a, a composite spine 500 is shown. This spine may be formed from a metal or composite material leading section 501 and a fibre-glass, carbon fibre or plastic trailing section 502. The trailing section may be shaped to incorporate reflex (i.e. a slight upturn in the trailing edge). This is known to improve the aerodynamic characteristics of the kite to a degree.

Alternatively, the spines may be formed from a single piece of material, in such a construction, the spine may be pre-shaped to exhibit an airfoil shape, optionally with reflex in the trailing edge.

A further spine construction is shown in figure 5b. This corresponds to a 'split spine' and is formed from an upper part 504 and lower part 505. The parts may be either pre- shaped or have a differential length and/or rigidity so that when they are joined end-to- end, bowing is induced thereby forming an airfoil-like shape (when viewed in section). In such cases, the spine sleeve in the kite skin would need to be adapted to accommodate the particular spine construction.

Referring to figure 5c, a composite spine having camber and a flat trailing edge is shown. Here the top portion 506 is shorter than the lower 507. The top portion may be shaped suitably so that it naturally assumes a cambered shape. Alternatively, the spine can use the inherent resilience of the material to join the top portion to the lower by means of attachment points 510 and 509. In this latter case, the top portion would be shaped to conform to a shorter length whereby a camber would be induced in the top portion. In such a construction the lower portion 507 may be stiffer than the top portion so that it resists flexing and the spine shape as shown in figure 5c is produced. In this configuration reflex may be incorporated into the trailing edge.

The leading edge is flexible and may be manufactured from fibre-reinforced plastic, composite materials or the like. In one embodiment, the flexible leading edge member may be in the form of a bundle or two or more flexible sub-members (not shown). This construction is capable of being bent or looped for storage/transport more easily than a single leading edge member. This is because the radius of curvature of the member is proportional to the cross sectional diameter of the member amongst other factors. The inclusion of a bundle of flexible leading edge members, while providing the desired support characteristics, may therefore be bent at a smaller diameter in comparison to a single flexible leading edge member. Also, in certain applications, where long leading edges are used (sailing, kite-powered kayaking etc) it may be impractical to coil the leading edge. To overcome this problem, the leading edge may be hinged or jointed at various points - preferably at spine/leading edge junctions.

The orientation of the spines is preferably substantially parallel to the longitudinal axis of symmetry of the kite. However, it is possible that there may be some variation in this orientation - for example the spines 1 2a and 1 2b (in either primary or secondary embodiments) may be oriented so that the end of the spine closest to the trailing edge is further towards the tip thus orienting the spine outwardly in a splayed fashion. It is thought that the orientation of the spines aids the directional stability characteristics of the kite. Ideally, the kite should fly into the apparent wind so as to retain a reasonably uniform airflow over the whole kite surface. The effect of positive pressure under the kites skin and the spines will cause localised pressure increase and billow between the spines. The will cause a channeling and rudder-like effect which will tend to orient the kite into the effective airflow. However, this is not always desirable for traction kites (particularly large kites) as it slows turning.

An alternative method of attaching the spines to the kite skin is shown in figure 6. According to this construction, the kite skin incorporates a plurality of fabric webs or ribs 600. These project substantially downwardly from the plane defined by the kite skin. The spine may, in this construction, be inserted along the lower edge of the rib in a sleeve formed in the edge 601 .

Alternatively, separate spine parts may be inserted into an upper and lower sleeve 602 and 601 respectively and possibly joined at the trailing and leading edge or alternatively (and depending on the particular construction of the fabric rib) at an intermediate point. Usually, the lower spine will not be sleeved.

This construction produces a kite skin which has a relatively flat upper surface with a well defined camber. Further, the presence of the ribs reduces spanwise airflow which may be desirable depending on the type of kite which is being manufactured. Either all or a selection of the spine attachment means may be in the form shown in figure 6. The particular selection of number of ribbed spines may depend on the total span of the kite and the number of spines which are included in the kites construction.

A bridling arrangement suitable for such a kite is illustrated in figures 1 , 2 and 3. For clarity, the bridling has been split into three figures for clarity. The particular version shown is for a four-line kite. However, a version of the improved kite could be used with two or three lines. The leading edge incorporates a number of attachment points 91 a, b, 92a, b, 93a, b, 94a, b, 95a, b which are connected to lines 3 and 4 via primary bridling 80a, 81 a, 82a, 80b, 81 b, 82b, 53a, 53b, 70a and 70b. This bridling distributes line tensions to the flexible leading edge and spines and then to the skin of the kite where it is opposed by aerodynamic loadings.

The leading edge and/or the spines are preferably constructed from materials having dimensions and composition adapted so that these members are capable of being bent as follows. When storing kites, it is common to disassemble the frame or spar structures of the kite. In the present invention, it has been found that the particular spar characteristics used in the present kite construction allow the kite to be stored without being disassembled. To this end, the kite leading edge is coiled by twisting the leading edge inward on itself. As this is done, the spines assume a position which is approximately parallel to the leading edge. The bundle of spars including spines and the leading edge is then grasped by a user and twisted through a complete coil. The resulting coiled part of the kite can then be inserted into a bag which prevents the kite from unfolding and protects and stores the kite in a rapid and effective manner. A prototype kite constructed in accordance with the invention may be coiled as described above into a 0.65m diameter disc-shaped bag. For example, a 2.6m² 3-spine kite has a wingspan (when in flight) of about 2.5m, a maximum chord (centre spine length) of 1 .4m. It uses for a leading edge, rod which is either 4.5mm in diameter GRP (Glass reinforced plastic) or 3.2mm diameter CRP (carbon reinforced plastic). The spines may have similar dimensions for corresponding materials. For larger kites, it is conventional to increase the number of bridles attached to the spines.

Primary bridling attached to the spines 51 , 52, 53, 60, 61 and 62 provides attachment points to generally evenly spaced locations along the spines 12. This bridling is also connected to lines 3 and 4 via intermediate bridling as shown. Secondary bridling may be used and in the present context corresponds to the lines attached between the primary bridling and the control lines. Trailing edge bridling 40, 41 and 42 is shown in figure 1 . These lines are attached to the trailing edge spine tips and, via secondary bridling, to lines 1 and 2.

The bridling arrangement includes asymmetric bridling connecting lines 3 and 4 as shown in figure 2. As noted above, rigid bridling may be used.

The net effect of the bridling arrangement is to accept the aerodynamically induced loads and transmit them to the flying lines without inducing large forces in the spines and/or leading edge members. The trailing edge bridling provides angle of attack control and differential tension in the bridling is applied via lines 3 and 4 provides directional control as is -generally known in the art.

In use, the forces applied via the spines in conjunction with the relatively flexible leading edge member sustain the shape of the kite but allow it to flex as required under varying loads brought resulting from variable turning actions, wind speeds, kite orientations and angle of attack. It has been found, surprisingly, that a fully rigid leading edge spar is not needed and sufficient span-wise rigidity to resist aerodynamic loading is produced by the span-wise pressure differentials acting on the skin of the kite and these pressure differentials are, additionally, sufficient also to resist the span-wise compressive loads applied to the kite by the bridles.

The number of spines, and the inclusion of secondary spines, may be varied depending on the particular dimensions of the kite and its shape. Similarly, the number of spine attachment and leading edge attachment points may be varied according to the skin design. The example shown in the figures includes insert panels 1 6a,b. These provide for increased skin surface area in the leading edge area and thus produce a cambered airfoil shape.

Further, the kite skin may, as noted above, incorporate foam portions to assist in floatation of the device. However, the kite skin may alternatively be manufactured entirely from a foam composite material comprising a foam layer and one or more fabric laminate. It is also possible that some of the panels of such a kite may be in the form of solely fabric panels. The particular arrangement would depend on the desired weight distribution of the kite sail and the amount of floatation which is required.

The flight characteristics in terms of efficiency and controllability of the improved kite have been found to be very desirable. Dispensing with the rigid leading edge spar has also led to a reduced manufacturing cost and the construction of the kite is often slightly more simplified than those designs having rigid, highly loaded leading edges and fewer bridle attachment points. When used in traction kiting, it has been found that the improved kite is highly effective and easy to use.

Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth.

Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or improvements may be made without departing from the scope of the appended claims.

Claims

WHAT I CLAIM IS:

1 . An improved kite including: a kite skin having a leading edge and a trailing edge; a flexible leading edge member which is small in diameter in proportion to the maximum chord of the kite; and one or more flexible spines attached to the skin, substantially over their entire length, wherein span-wise rigidity of the kite is provided substantially by components of pressure differential across the skin of the kite acting in substantially span-wise directions, in conjunction with interaction with bridling attached to the flexible leading edge member and at least two of the spine(s) .

2. An improved kite including: a kite skin having a leading edge and a trailing edge; a flexible leading edge member; and one or more flexible spines attached to the skin, substantially over their entire length, wherein the leading edge member and/or the spine(s) are adapted to be sufficiently flexible that the entire assembled kite can be packed in a coiled form.

3. An improved kite as claimed in claim 1 wherein the spines comprise primary spines traversing the centre of the skin from the leading edge to the trailing edge, and secondary spines running from a point on the skin behind the leading edge to the trailing edge.

4. An improved kite as claimed in any preceding claim wherein the spines are oriented substantially parallel with the longitudinal axis of symmetry of the kite.

5. An improved kite as claimed in claim 1 wherein the bridling includes a plurality of connection points along the leading edge and a plurality of connection points along the length of the spines.

6. An improved kite as claimed in claim 5 wherein the connection points along the spines include a connection point at the junction of the spine and the leading edge (for primary spines), or at a point on the spine (for secondary spines) and the junction of the spine and the trailing edge, along with one or more connection points between the forward end of the spine and trailing edge junction.

7. An improved kite as claimed in any preceding claim wherein the bridling arrangement is in a form adapted for control of the kite by means of two or more lines.

8. An improved kite as claimed in claim 1 wherein the kite skin is shaped so that camber is provided.

9. An improved kite as claimed in claim 1 wherein the skin includes foam sections located behind the leading edge.

10. An improved kite as claimed in claim 1 wherein the kite skin is constructed from foam, preferably the foam being laminated to or between one or more fabric layers.

1 1 . An improved kite as claimed in claim 1 wherein the skin has panels constructed incorporating foam and/or panels constructed from a fabric.

1 2. An improved kite as claimed in claims 9, 1 0 or 1 1 wherein the foam is expanded polyethylene foam or similar material which exhibits the required degree of floatation.

1 3. An improved kite as claimed in any previous claim wherein camber is provided by incorporating insert panels that increase the area of skin in a region immediately behind the leading edge.

14. An improved kite as claimed in any previous claim wherein the kite skin incorporates, when viewed in plan, a curved leading edge and a substantially straight trailing edge.

1 5. An improved kite as claimed in claim 14 wherein the trailing edge is scalloped.

1 6. An improved kite as claimed in any previous claim wherein the spines are shaped to assist in providing camber in the kite skin.

17. An improved kite as claimed in claim 1 wherein the flexible leading edge member comprises two or more flexible sub-members in a bundle and located at the leading edge, preferably in a sleeve, of the kite.

18. An improved kite as claimed in claim 1 wherein the leading edge member is collapsible, the collapsible functionality effected by means of one or more hinges located at the junction of the leading edge and the spines.

19. An improved kite as claimed in claim 1 8 wherein the hinges are in the form of a hinge and pin type arrangement.

20. An improved kite as claimed in claim 1 wherein the spines include built-in reflex.

21 . An improved kite as claimed in claim 20 wherein the reflex is produced by constructing the spine from a combination of materials.

22. An improved kite as claimed in either claim 20 or 21 wherein the spines are constructed in a composite form.

23. An improved kite as claimed in claim 22 wherein the spine is constructed with a metal forward section and a fiberglass rear section.

24. An improved kite as claimed in claim 22 wherein the rear section is a carbon fiber or similar material.

25. An improved kite as claimed any preceding claim wherein the rear section of the spines incorporate built-in reflex.

26. An improved kite as claimed in any previous claims wherein the spines are joined to the kite skin by means of a fabric rib or web lattice or open weave fabric, or foam or part foam section.

27. An improved kite as claimed in claim 26 wherein the fabric rib extends below the kite skin whereby the fabric rib is adapted to receive the spine so that when a pressure differential exists between the upper and lower surface of the kite skin, spanwise movement of air substantially immediately under the kite skin is reduced or substantially prevented.

28. An improved kite as claimed in any previous claim wherein the spines are constructed in two parts, an upper and a lower part, wherein the upper part has the shape of an airfoil and the lower part has either a generally linear shape or is curved.

29. An improved kite as claimed in claim 28 wherein the upper and lower parts are of different length with the upper part extending from a point proximate the leading edge of the spine to a point between the leading and trailing edge of the resulting spine whereby the upper part is shorter than the lower part and is joined to the lower part so that an airfoil shape is produced between the upper and front portion of the lower part.

30. An improved kite as claimed in any previous claim wherein some or all of the bridles are in the form of rigid bridles.

31 . An improved kite as herein described with reference to the accompanying drawings.