WO2003080434A1

WO2003080434A1 - Tubekite with an improved aerodynamic profile

Info

Publication number: WO2003080434A1
Application number: PCT/EP2003/003051
Authority: WO
Inventors: Georg Koziel
Original assignee: Georg Koziel
Priority date: 2002-03-26
Filing date: 2003-03-24
Publication date: 2003-10-02
Also published as: AU2003222775A1

Abstract

The invention relates to a kite, especially what is known as a tubekite, comprising an upper sail (3a) and a lower sail (3b) and a first flexible hose (2) which extends along the front side of the tubekite and which is inflatable and which is arranged between the upper sail and lower sail. According to the invention, at least one second inflatable profiled flexible hose (4) is arranged in a substantially parallel manner in relation to the first flexible hose between the upper sail and the lower sail. The first flexible hose and the profiled flexible hose are respectively joined to the upper sail and lower sail in such a way that the first flexible hose and the profiled flexible hole are pressed against each other when inflated. Alternately, the additional profiled flexible hose can also be fixed between the first flexible hose and a single-pieced sail surrounding the first flexible tube.

Description

Tubekite with improved inflow profile

The invention relates to a kite, in particular a so-called tube kite according to the preamble of patent claim 1.

From DE 27 27 411 AI a structure of a wing for light aircraft, in particular kites and hang gliders is already known, in which a double sail is provided, which is stretched between a tubular spar lying on the front of the wing and a profile end wire lying on the rear of the wing is and encloses both tubular spar and profile end wire. In addition, an inflatable, tubular rib construction is provided within the double sail, through which the outer contour of the double sail is given an aerodynamically desired profile shape.

Furthermore, from US 4,708,078 AI a generic kite with inflatable structures is known, which consists of a tube that runs along the front of the wing, the so-called front tube, and several tubes that run perpendicular to this front tube, the so-called transverse tubes. These inflatable structures give this kite its shape and rigidity. The tubes are surrounded by an upper sail and a lower sail, which are connected to the hoses at the points of contact, the upper and lower sails also being connected to one another in the rear region of the airfoil and thus forming a closed envelope around the inflatable structures. The dragon points out on the two fastening points arranged at opposite lateral ends of the leading edge and two lines connected to the tubekite at the fastening points. These lines run from the tube kite to the athlete and are used to maneuver the tube kite.

Such tube kites have the disadvantage that the round shape of the front tube and its large diameter result in a high inflow air resistance. The diameter of the front hose of such a kite is generally determined by the geometry of the kite. The exact diameter that is necessary for a stable shape is chosen. The aerodynamics are only considered secondarily. Since the front hose has a round shape, the diameter of the hoses results in a high inflow air resistance. As a result, the screens are slow. Small kites reach a wind window size of approximately 175 degrees, which decreases with the size of the kite. The same applies to control impulses, these also get worse with increasing size. In addition, such tube kites have the disadvantage that a semicircular cross section is formed by design, which causes an increased material requirement and thus high manufacturing costs.

The object of the invention is to create a kite with an improved inflow profile which is nevertheless easy to produce.

This object is solved by the subject matter of claim 1. Advantageous designs are the subject of further claims.

According to the invention, an additional inflatable profile tube is arranged between the upper and lower sails of the kite in such a way that the first tube and the profile tube in the blown state are pressed against each other. Pushing against each other creates a kite with sufficient rigidity. At the same time, an inflow profile deviating from the circular shape is formed. With this technique, it is possible to produce considerably more powerful kites.

According to the first alternative, both the first tube and the profile tube are connected to the top and bottom sails. The attachment points are chosen so that the tubes are pressed against each other when inflated.

According to the second alternative, the top and bottom sails are designed as a one-piece sail, which wraps around the first tube at least on the front side and is connected to it on opposite sides. In the front area between the first tube and the sail, an additional inflatable profile tube is arranged such that the first tube and the profile tube are pressed against one another.

By arranging several profile hoses one behind the other in the direction of flow, the entire flow profile of the kite can be designed even more individually according to the respective wishes of the designers; especially when the hoses have different radii.

In the event that the radii of the hoses increase in the inflow direction, a wedge profile that is favorable with respect to the inflow air resistance can be realized. The arrangement of several fastening points in the circumferential direction for a hose provides further degrees of freedom for the profile design. In the longitudinal direction of the hoses, these can also be connected to the top and / or bottom sail at several points or continuously. In the case of the one-piece sail, by arranging at least one fastening point of the profile hose on the sail or on the first hose, a relative positional fixation can be achieved, so that twisting or slipping of the profile hose is reliably avoided.

Furthermore, the cross section of the generic tube kite can advantageously be changed by the arrangement of two struts. These struts each extend between one of the control lines and the kite. The connection points between strut and control line or between strut and kite are each spaced from the attachment point of the control line on the kite. This creates a balance of forces that leads to a change in the cross-section of the kite. Instead of the semicircular cross section, there is a flatter circular section. This enables material savings of over 40% to be achieved with the same efficiency as the kite.

It is advantageous if the struts are designed as a leash which are fixedly or detachably connected to the control lines and / or the kite.

A particularly favorable cross-sectional shape is achieved if the distance between the attachment point and the connection point between strut and kite is greater than the distance between the attachment point and the connection point between strut and control line.

Another advantage is achieved by the releasable arrangement of the struts. In this case, several connection points can be provided on the control lines and / or on the kite, so that the flight characteristics of the kite, in particular depending on depending on the prevailing wind or the skills of the athlete.

The cross section of the kite can be further optimized by arranging two additional struts in the region of the trailing edge of the kite, in particular for kites with at least four control lines.

The invention is described below by way of example with reference to a drawing, wherein

1 shows the basic structure of a conventional kite with two control lines in a perspective view,

2 shows the basic structure of a conventional kite with four control lines in a perspective view,

3 shows a schematic section through a first exemplary embodiment of a kite according to the invention,

4 shows a schematic section through a second exemplary embodiment of a kite according to the invention with a one-piece sail,

5 shows a schematic section through a third embodiment of a kite according to the invention with two additional profile tubes,

6 shows a schematic section through a fourth exemplary embodiment of a kite according to the invention,

7 shows a schematic section through the conventional kite according to FIGS. 1 and 2,

8 shows a schematic section through an improved kite. The shape and function of kites, in particular so-called tube kites, is general and in particular also known from US Pat. No. 4,708,078 A1, and is therefore only described briefly below.

The kite, identified overall by 1 in FIG. 1, has a wing 12 made of a suitable, preferably flexible material. In order to give the kite 1 a desired profile and to create a sufficiently rigid structure, an inflatable first tube 2, generally referred to as a front tube, is arranged in the region of the leading edge 6 of the kite 1. For this purpose, the hose 2 is made of an airtight material or has at least one airtight inner core. If the wire 1 is to be used on the water, a waterproof or water-repellent material is preferably used. The hose 2 extends essentially over the entire leading edge 6 and has a conical or also a symmetrical cross section. Furthermore, reinforcing structures 13 are usually additionally provided perpendicular to the hose 2, that is to say essentially in the flow direction 7 of the air, for the supporting surface 12. These can also be inflatable structures, so-called transverse tubes 13. Alternatively, flexible structures can also be provided.

An attachment point 11, 11 'for two control lines 8, 8' is provided on the laterally opposite ends of the leading edge 6. The control lines 8, 8 'are extended to the athlete (not shown) and are used to maneuver the tube kite 1. In addition to the kite with two control lines shown in FIG. 1, kites with four or more control lines are also increasingly being used, as shown in FIG. 2. Here, two additional fastening points are made for the two additional control lines 8 ″, 8 ″ ″ in the region of a trailing edge 9 of the kite 1 11 '', 11 '''provided. In this case, the wing 12 of the kite 1 is shaped such that the leading edge 6 and the trailing edge 9 do not meet at the attachment point 8, 8 ′ as shown in FIG. 1, but are spaced apart from one another in the direction of the flow 7. In such a kite 1 with four control lines 8, 8 ', 8'',8''', the two rear control lines 8 '', 8 '''are usually used to steer the kite 1, while the two front control lines 8, 8 '' can be used to adjust the flow angle (so-called depower lines).

3 shows a first exemplary embodiment of a kite 1 according to the invention. The actual wing 12 of the kite 1 is formed by an upper sail 3a, which is usually produced from a flexible material. In order to give the kite a desired profile and to create a sufficiently rigid structure, an inflatable first tube 2 is arranged in the region of the leading edge 6 of the kite 1.

According to the invention, the inflow profile of the kite 1 can now be made more optimal by additionally providing an inflatable profile tube 4. This profile tube 4 extends at the leading edge 6 essentially parallel to the first tube 2. Both the first tube 2 and the profile tube 4 are connected at opposite fastening points 5 to the top sail 3a and to an additional bottom sail 3b. While the upper sail 3a extends beyond the first hose 2 to the rear and forms the actual wing, the lower sail 3b in this exemplary embodiment only extends between the undersides of the two hoses 2 and 4.

In the exemplary embodiment, the radius r2 of the profile tube 4 is smaller than the radius r1 of the first tube 2. The fastening supply points 5 are arranged so that the first tube 2 and the profile tube 4 are pressed against each other in the inflated state. This means that the distance a between the two theoretical hose axes is smaller than the sum of the radii rl + r2 of the two hoses 2, 4 when inflated. The two hoses 2, 4 pressed against one another result in a relatively rigid construction. At the same time, the two hoses and the upper sail 3a and lower sail 3b surrounding them form an inflow profile that deviates from the circular shape. This inflow profile can be designed according to the respective wishes of the designers. With this technology it is possible to produce new, more powerful tube kites. The radius r of the hoses preferably increases in the flow direction 7, so that the flow profile takes on a wedge shape overall, which is advantageous in terms of aerodynamics.

3, the upper and lower sails 3a, 3b are made in one piece in the exemplary embodiment according to FIG. 4. The resulting sail 3 wraps around the first tube 2 in the region of the leading edge 6 and is simultaneously connected to it by means of fastening points 5 arranged on opposite sides of the first tube 2. In the area of the leading edge 6, the profile tube 4L is also arranged between the first tube 2 and the sail 3. The fastening points 5 on the first tube 2 are in turn arranged such that the first tube 2 and the profile tube 4 are pressed against one another in the inflated state. In this embodiment, no fastening points 5 are provided for the profile tube 4, since the profile tube 4 is automatically clamped between the first tube 2 and the one-piece sail 3 when it is inflated and is therefore fixed. In order to prevent twisting of the profile tube 4 relative to the first tube 2, it is of course also possible between the profile tube 4 and one or more fastening points 5 are provided for the sail 3 or the first tube 2.

In contrast to the first exemplary embodiment, the sail 3 is also extended in the lower region to the rear beyond the first tube 2 and connected to the upper sail at its rear end. As a result, turbulence in the area behind the first hose 2 can be prevented or at least reduced.

In the exemplary embodiment according to FIG. 5, two profile hoses 4, 'are provided, the radii r3, r2, rl of the hoses 4', 4, 2 again increasing in the flow direction 7. Depending on the desired profile, the radii can also be selected in other relations. In this exemplary embodiment, the sail 3 is again made in one piece, but extends only to the lower attachment point 5 on the first tube 2. The profile tube 4 is also connected to the sail ^" 3 via an upper and a lower attachment point 5, while the second profile tube 4 is in turn clamped between the sail 3 and the profile tube 4. In this case too, of course, a further attachment point for the second profile tube 4 'can be provided.

In the fourth embodiment shown in FIG. 6, two profile tubes 4, 4 'are again provided. 5, the profile tube 4 is connected to the sail 3 via two fastening points 5 on the opposite sides. In addition, the second profile tube 4 'is connected to the first profile tube 4 via an additional fastening point 5.

The hoses 2, 4, 4 'can be fastened to the upper or lower sail 3a, 3b in any manner, for example by gluing or sewing. In general, two, three or more hoses 2, 4, 4 'can be connected in this way. An individual inflow profile can be produced by the position and the number of fastening points 5 on the hoses 2, 4, 4 'and by the choice of the radii of the hoses 2, 4, 4'. The tubes can be inflated individually. Alternatively, they can also be connected via appropriate lines so that they can be inflated in a single operation. By using at least two hoses 2, 4, 4 'connected by an upper and lower sail 3a, 3b, a flow profile deviating from the circular shape can be achieved in a simple manner. The fact that the tubes 2, 4, 4 'are pressed against one another after inflation, enables a simple and stable construction. Arrangements are also possible in which the tubes 2, 4, 4 'are spaced apart. In this case, however, additional structures are required which ensure the spacing of the hoses and prevent instability.

Another possibility to further increase the freedom of design is the arrangement of connecting elements between the upper sail 3a and the lower sail 3b at the locations where the tubes 2, 4, 4 'touch after inflation. The distance between the upper sail 3a and the lower sail 3b is thus precisely defined at this point. At the same time, the hoses 2, 4, 4 'can press against one another and thus ensure stability. These connecting elements can be made of the same material as the top and bottom sails 3a, 3b and can extend in the longitudinal direction of the hoses 2, 4, 4 'either aisle or only in regions.

FIG. 7 shows the cross section of conventional kites 1 again in section, the same parts being identified with identical reference numerals. It can be seen that the Hose 2 and thus also the wing 12 of the kite 1 takes on a semi-circular shape due to the type of construction.

8 shows a kite 1 according to the invention with additional struts 10, 10 '. The struts 10, 10 'are connected to the control lines 8, 8' via connection points A, A 'and to the kite 1 via connection points B, B'.

The arrangement of the struts 10, 10 'results in a changed balance of forces and, as a result, a changed cross-sectional shape. Instead of the semicircular shape, there is a flatter section of the circle. This allows material savings of up to 40% to be achieved with the same efficiency as the kite 1. This results in a kite 1, which is nevertheless cheaper to produce with comparable flight characteristics. This improved cross-sectional shape can be achieved both in combination with the improved inflow profile according to claim 1 and for conventional kites 1 according to FIGS. 1 or 2.

In the case of a kite 1 with only two control lines 8, 8 ', the struts 10, 10' are inevitably connected to these two control lines via the connection points A, A '. In this case, the connection points B, B 'between the struts 10, 10' and the kite 1 are preferably arranged in the region of the leading edge 6 or the hose 2. Depending on the overall construction of the kite 1, it is in principle also conceivable to arrange the connection points B, B 'in the region of the trailing edge 9 or in the region between the leading edge β and trailing edge 9.

In the case of a kite 1 with four control lines 8, 8 ', 8'',8'' ¹ , the struts 10, 10' are advanced via the connection points A, A '. preferably connected to the two front control lines 8, 8 '. In principle, however, it is also possible here to connect the struts 10, 10 ′ to the two rear control lines 8 ″, 8 ″ ″ or, if appropriate, a combination thereof. In this case, the connection points B, B 'between the struts 10, 10' and the kite 1 are preferably likewise arranged in the region of the leading edge β or the hose 2. Depending on the overall construction of the kite 1, it is in principle also conceivable here to arrange the connection points B, B 'in the region of the trailing edge 9 or in the region between the leading edge β and the trailing edge 9.

Another possibility for a kite 1 with four control lines 8, 8 ', 8' ', 8' "'is to provide a total of four struts 10, 10'. This further increases the freedom of design in the construction of the kite 1. Preferably In this case, two struts 10, 10 'are provided, each of which connects the front control lines 8, 8' with the kite 1 in the region of the leading edge 3 or the hose 2, while two further struts 10, 10 'connect the rear control lines 8' ' , 8 '' 'to the kite 1 in the area of the trailing edge 9 or in the area between the leading edge β and the trailing edge 9.

The struts 10, 10 'are preferably formed by a further line. In principle, however, any other rigid or flexible materials can be used. The struts 10, 10 'can be firmly connected to the control lines 8, 8', 8 ¹ ', 8''' or the kite 1 at the connection points A, A ', B, B'. However, the connection is preferably detachable with a view to simple assembly / disassembly. In addition, with a detachable connection, it is possible to provide several optional connection points A, A ', B, B' on the control lines 8, 8 ', 8'',8''' and / or on the kite 1, so that the flight characteristics of the kite 1, in particular depending on the prevailing wind or the skill of the athlete, can be changed by using different connection points

Another degree of freedom in the construction of a kite 1 according to the invention consists in the arrangement of the connection points A, A ', B, B' with respect to the fastening points 11, 11 '. Preferably, the distance between the attachment point 11, 11 'and the connection point B, B' between the strut 10, 10 'and the kite 1 is chosen larger than the distance between the attachment point 11, 11' and the connection point A, A 'between the Strut 10, 10 'and the control line 8, 8', 8 '', 8 '' '. This forms a cross section corresponding to a relatively flat circular section, which is particularly advantageous in terms of material savings.

Claims

claims

1. kite (1), in particular tube kite, with an upper sail (3a) and a lower sail (3b) and a first tube (2) which extends along a leading edge (6) of the kite (1) and which is inflatable and between the upper and bottom sail (3a, 3b) is arranged and connected to it, characterized in that an additional profile tube (4, 4 ') is arranged between top and bottom sail (3a, 3b), which is inflatable and essentially parallel to the first tube ( 2) is arranged, whereby

- The first tube (2) and the profile tube (4, 4 ') are each connected to the upper and lower sails (3a, 3b) in such a way that the first tube (2) and the profile tube (4, 4') are inflated State pressed against each other, or

- The upper and lower sail (3a, 3b) is designed as a one-piece sail (3) and wraps around the first tube (2) at least in the region of the leading edge (6), and the additional profile tube (4, 4 ') between the Sail (3) and the first tube (2) is arranged such that the first tube (2) and the profile tube (4, 4 ') are pressed against each other in the inflated state.

2. Kite according to claim 1, so that a plurality of profile hoses (4, 4 ') lying one behind the other in the flow direction (7) are provided.

3. Kite according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the hoses (2, 4, 4 ') have different radii (rl, r2, r3).

4. kite according to claim 3, so that the radii (rl, r2, r3) of the hoses (2, 4, 4 ') increase in the direction of flow (7).

5. Kite according to one of the preceding claims, characterized in that the lower sail (3b) extends only over the front part of the upper sail (3a) in the flow direction (7) and with this at the rear end of the lower sail (3b) in the flow direction (7). connected is.

6. Kite according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that a hose (2, 4, 4 ') in the circumferential direction at several fastening points (5) with the upper and / or lower sail (3a, 3b) is connected.

7. Kite according to one of the preceding claims, characterized in that a hose (2, 4, 4 ') is connected several times or continuously in the longitudinal direction to the upper and / or lower sail (3a, 3b).

8. Kite according to one of the preceding claims, characterized in that between the upper sail (3a) and the lower sail (3b) at the locations where the tubes (2, 4, 4 ') touch after inflation, flexible connecting elements are arranged ,

9. kite according to claim 2, d a d u r c h g e k e n n z e i c h n e t that the profile tube (4, 4 ') is connected in the circumferential direction at least at one fastening point (5) with the sail (3) and / or the first tube (2).

10. Kite according to one of the preceding claims, characterized in that two fastening points (11, 11 ', 11'', ll ¹ '') arranged on the opposite lateral ends of the leading edge (6) and two at the fastening points (11, 11') , 11 '', 11 ''') control lines (8, 8', 8 '', 8 ' ¹ ') connected to the kite (1) are provided for maneuvering the kite (1), and two struts (10, 10 ') are provided, which are spaced from the respective attachment point (11, 11', 11 '', 11 ''') for changing the cross-section of the kite (1), each with a control line (8, 8', 8 '', 8 ¹¹ ') and connected to the kite (1).

11. kite according to claim 10, d a d u r c h g e k e n n z e i c h n e t that the struts (10, 10 ') are formed by lines.

12. Kite according to claim 10 or 11, characterized in that the distance between the attachment point (11, 11 ', 11'',11''') and a connection point (B, B ') between the strut (10, 10') and Kite (1) is greater than the distance between the Attachment point (11, 11 ', 11'',11''') and a connection point (A, A ') between strut (10, 10') and control line (8, 8 ', 8'',8''') ,

13. Kite according to one of claims 10 to 12, characterized in that the strut (10, 10 ') releasably connected to the control line (8, 8', 8 '', 8 ' ¹ ') and / or the kite (1) and that to change the flight characteristics several connection points (A, A ', B, B') are provided on the control line (8, 8 ', 8'',8''') and / or on the kite (1).

14. kite according to one of claims 10 to 13, d a d u r c h g e k e n n z e i c h n e t that the kite (1) additionally has:

- Two fastening points (11 '', ll ' ¹ ') arranged at the opposite lateral ends of a trailing edge (9),

- two control lines (8 '', 8 '' ') connected to the kite (1) at the attachment points (11' ', 11' ''),

- Two struts (10, 10 ') which are used to change the cross section of the kite (1) spaced from the respective attachment point

(11 '', 11 '' ') are each connected to a control line (8' ', 8' "') and to the kite (1).