DE20220025U1 - Kite has profile skeleton line with profile trailing edge pointing upwards when line is relaxed, with curvature or profile of kite variable by variable tensioning of braking line anchored in vicinity of profile trailing edge - Google Patents

Abstract

The kite (22) has a profile skeleton line with a profile trailing edge (15) pointing upwards when the line is relaxed. The curvature or profile of the kite is variable by a variable tensioning of a braking line (40,42) anchored in the vicinity of the profile trailing edge, or is variable by a variable tensioning of the control line. The kite has elastic restoring elements anchored in the vicinity of the profile trailing edge and in a center upper profile region. An upper sail of elastic material creates a S-shaped profile of the kite in the relaxed state of the lines.

Description

FLYGM02066 ·! * . Ij.. · · · 12/20/02

Applicant: skywalk GmbH & Co. KG

Birkenweg 3 82224 Grassau

Self-stable kite

Description

The sport of kitesurfing has become established recently. Kitesurfing is a form of locomotion similar to surfing or waterskiing/wakeboarding. An athlete - known as a kiter or kitesurfer - stands on a type of small surfboard on the water and is pulled by a kite. The kite is held and controlled by the kitesurfer on lines and is in the wind at a height of around 10 to 50 meters above the water. At this height, the kite encounters favorable winds. In this way, a fast movement, similar to waterskiing, can be achieved.

' The kite is a controllable paraglider, similar to a paraglider or stunt kite, i.e. a flexible flying wing. Depending on where the kite is directed, the direction and strength of the kite's pulling force can be changed. The power or pulling force of the kite always acts in the direction of the lines. The kite has an airfoil shape, which means that an effective force can be achieved perpendicular to the direction of the airflow. This also makes it possible to sail against the wind, like with a windsurfer or sailboat.

In general, such kites are also suitable for propelling sailing boats, ships or land vehicles.

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There are basically two types of kites for kitesurfing, namely so-called tube kites and so-called soft kites.

A tube kite contains closed volume elements, air tubes or chambers that are inflated like an air mattress, closed with plastic valves and keep the tube kite in the shape of a wing. Alternatively, a tube kite can also be kept in shape by sail battens. A simple sail is usually stretched over the inflated volume elements. Tube kites are usually primarily used on

held or suspended from the wing tips. I

A soft kite does not contain completely closed chambers.

It consists of an upper sail and a lower sail, which are connected to one another at a profile leading edge and a profile trailing edge and are given their shape by profiles. A soft kite also has at least one air inlet opening in the lower sail, each with an associated valve through which incoming air enters the interior of the soft kite. Similar to a paraglider, the soft kite automatically fills with air in the wind to achieve an airfoil shape.

f In practice, there are also hybrids of both systems. All of these kite shapes can be used on water as well as on land and usually have curved, buoyant profiles to achieve high pull or propulsion. In order to increase the lift (so-called "powering") or to reduce it (so-called "depowering"), the method of changing the angle of attack is usually used. Other systems increase

the lift by strengthening the profile curvature using so-called brake lines. The rear edge of the kite (especially soft kites) is pulled downwards, the profile is thus curved more, which increases the overall lift. 35

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However, the use of such high-lift profiles can lead to problems. If the kite comes far forwards in the direction of the rider, for example due to the influence of gusts of wind or due to driving errors, the kite is in danger of crashing with the leading edge first due to the generally top-heavy profile moment. This can sometimes lead to dangerous situations, for example if the lines suddenly come under tension again or if the kite gets caught in the lines and can no longer be controlled.

The object of the invention is to provide an improved kite in which, in the event of a stall, there is no danger of a sudden crash due to a lack of lift and, at the same time, the lift of the kite can be changed extremely.

This object is achieved by the invention according to the independent claim. Advantageous further developments of the invention are characterized in the subclaims. 20

The kite according to the invention has an S-shaped profile, in which a profile nose points downwards and a profile trailing edge points upwards when the lines of the kite are not under tension. The upward-pointing trailing edge means that if the kite threatens to fall forwards, the profile trailing edge is pressed downwards and thus returns to a horizontal position. The kite is then inherently stable, i.e. it does not fall.

The safety gain and the wind range of such a kite system is significantly increased compared to known systems. The invention ensures that the kite does not fall forward when the lines are relieved, but rather straightens up slightly and is blown backwards again by the wind. The lines are then put under tension again,

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which makes it easier to overcome critical situations.

The curvature or profile of the kite can be varied by varying the tension of the brake lines that are attached near the trailing edge of the profile. Alternatively or additionally, the curvature or profile can be varied by varying the tension of the control lines.

In order to create the kite's inherently stable profile when the lines are relaxed, elastic recovery elements can be provided on the upper profile area, for example in the form of elastic bands or similar. Alternatively, the upper sail can be made of an elastic material that automatically returns to the S-shaped profile when the lines are relaxed. Flexible elements can also be provided in the profile area of the reversal or bend point of the kite, which ensure that the S-shaped profile is created when the lines are relaxed.

An advantageous design can be a kite that is suspended on only one level, preferably the front level, when depowered and whose profile has what is known as wind vane stability, so that there is a moment equilibrium. The kite can then "blow out" from the power zone on the front level, for example, when taking off. This can drastically reduce the otherwise sometimes strong pulling forces in this situation.

The invention is explained in more detail below using embodiments that are shown schematically in the figures. The same reference numbers in the individual figures refer to the same elements. In detail:

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Fig. 1 a known line system with a bar for steering

of a kite in schematic representation; Fig. 2 a schematic representation of the line system at the end facing the kiter in the absence of a bar; Fig. 3 a schematic representation of a pulley for the

pressureless depowering;
Fig. 4 and 5 show a self-stable soft kite in schematic representations;

Fig. 6 and 7 the soft kite according to Fig. 4 and 5 with a flexible element for producing an S-stroke

profile;
Fig. 8 a line system according to claim 10, which is designed substantially symmetrically about the horizontal axis/depower line (111); Fig. 9 a line system according to claim 11, which is designed substantially symmetrically about the horizontal axis/depower line (111), and with a

double roller system; and Fig. 10 a self-retracting safety line. 20

Fig. 1 shows a line system of a kite 22 in a schematic representation. The way it works is explained below. If the left control line 12 is pulled, the trailing edge 15 of the profile is pulled downwards via the left brake line 40 on the left wing end 13. On the other hand, the connecting line also pulls the kite 22 in the left area as a whole and thus also the profile nose 11 downwards, but due to the deflection in the deflection device 48, only by half the distance of the left brake line 40. By pulling the trailing edge 15 of the profile down, the air resistance on the left side is increased. By pulling the rest of the left kite including the profile nose down halfway, a stall is delayed. The bend between the left and right

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By pulling the right half of the kite, an additional force component is achieved in the direction of the curve. On the right side, air resistance is simultaneously reduced by releasing the brake by lifting the right outer end of the bar 10. This allows the kite 22 to turn very tightly and precisely. The same applies when pulling on the right control line 14.

If both control lines 12, 14 are pulled at the same time, the kite 22 is curved and experiences a steeper angle of attack in the wind. It then experiences a stronger lift in the wind, which causes the kite 22 to be powered up.

The depower line 24 and the two control lines 12, 14 are taut in flight, as they keep the soft kite in shape via the risers 51 and gallery lines 52. By pulling on all three lines that are connected to the kiter or the bar 10 (depower line 24, control lines 12, 14), it is possible to extend the lines longer than with other line systems, without the flight characteristics becoming spongy and indirect due to sagging lines. The kite can therefore be at a higher altitude and can handle stronger winds there.

which allows the kiter to surf faster. I

If the depower line 24 is pulled, this causes the risers or gallery lines 52 to be pulled. The kite 22 is pulled downwards overall. The brake lines 40, 42 remain unchanged, i.e. they are extended relative to the rest of the kite 22. The profile trailing edge 15 is thus raised relatively. The kite is de-curved and experiences a flatter angle of attack. The dynamic pressure and possibly elastic restoring elements (see Fig. 6 and 7) cause the profile trailing edge 15 to be set up into an S-profile or an S-stroke profile, which reduces the lift coefficient of the kite.

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If the depower line 24 is released, the kite is in the powered state, and the brake lines 40, 42 are shortened relatively. Their length is chosen so that they are under tension in the powered state and arch the profile.

With tube kites, depowering is done via the depower line, which attaches to the profile nose at the wing tips, primarily via a change in angle of attack.

The line system also includes a safety leach 34, which is attached at both ends to a control line that can still be connected to the kitesurfer and whose length is chosen so that it does not exert any tension on the control lines 12, 14 during normal flight. This safety leach 34 can be attached to the trapeze or to the arm of the kitesurfer, for example. If the bar 10 is released, the safety leach 34 holds the two control lines 12, 14 firmly, while the middle line 24 is completely released. The flow on the kite breaks off and the trailing edge flips over. The kite falls into the air without pressure in backward flight.

water or on the ground.
I

If both control lines are pulled far enough by pulling the safety leach, the kite 22 will go into reverse flight. The kite can then be easily and immediately relaunched when it is in the water with the profile nose 11 first.

If the two control lines are pulled harder during flight than is necessary for backward flight, the entire profile trailing edge 15 bends over. The flow around the wing profile breaks off cleanly and the kite sinks into the water or to the ground without pressure in slow backward flight.

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Fig. 2 shows a schematic representation of the line system at the end facing the kiter in the absence of a bar. The bar can be replaced by handles 62, 64 at the end of the control lines 12, 14. To save energy, the pressureless depower system can be applied to this further development. To do this, the depower line 24 is split into two lines 58 and 60 after being deflected by the depower rope roller 54 and guided to the handles 62, 64 on the control lines 12 and 14. This further development is particularly suitable where a bar is a nuisance, such as in the baggy sports area.

Fig. 3 shows a schematic representation of a pulley for pressure-free depowering. The depower line 24 does not end in an eyelet 18 after being guided in the middle of the bar, but is instead guided back to the middle of the bar by a pulley 54, similar to the pulleys 48 and 50. The pulley 54 is connected to a depower line 18 directly or via a swivel.

0 When the kite surfer hooks the harness into this depower line, the pulling force on the bar 10 only corresponds to the very low pulling force of the brake lines 40, 42. Due to the rolling resistance of the rollers, the bar remains in the position in which it was released after being released. Only with relatively high pressure on the brake lines 40, 42 can the not undesirable effect of the kite depowering itself occur. Since the effort required in any position is practically eliminated, the harness line 20 is saved. The cumbersome switching between the harness line 20 and the depower line 18 is no longer necessary.

The left and right deflection devices 48, 50 and the deflection roller 54 are preferably designed as ball-bearing rollers. This results in low friction forces and the lines show little wear. The lines, which are

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Rollers must be relatively strong. The rollers should not have too small a radius to prevent excessive wear on the lines due to kinking.
5

Fig. 4 shows a self-stable soft kite according to the invention in a schematic representation from the side. In the representation shown, the kite 22 is in the relaxed state, in which the brake lines 36 anchored to the profile trailing edge 15 are in the relaxed state. The gallery lines 52, which are connected to risers 51 (not shown), can be in the slightly tensioned or relaxed state. A profile skeleton line 66, which extends from the profile nose 10 to the profile trailing edge 15, runs in an S-curve profile with the profile nose 10 pointing downwards and the profile trailing edge 15 pointing upwards and an inflection point 70 of the profile skeleton line 66 in between. When the gallery lines 52 are relieved of load and thus hanging freely, the kite profile 65 has an uprighting 0 pitching moment 68, which is illustrated by a curved arrow. The turning point 70 is preferably located at 25% to 95% of the profile depth. The kite profile 65 thus has a so-called "S-stroke" in the relaxed state.

Fig. 5 shows the kite profile 65 under load, whereby the lift coefficient is increased, even if the righting pitch moment 68 is reduced. The kite profile 65 is significantly changed by pulling on the brake line 36. The profile nose still points downwards. The profile trailing edge 15 is also strongly curved downwards, so that overall the lift coefficient increases significantly, typically by a value of about 50%. It is clear that the downwardly curved contour of the kite profile 65 is reduced by relieving the gallery lines 52, so that the profile trailing edge 15 rises upwards again. The

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The lift coefficient is thereby reduced and the kite can sink in a controlled manner. With the inventive, inherently stable kite 22, it can be ensured that the kite does not collapse forward when the lines are relieved of pressure, but rather straightens up slightly and is blown backwards again by the wind. The lines come under tension again, so that a critical situation can be overcome.

Instead of a curvature with a reversal point 70, the profile skeleton line 66 can also have a kink. To support the return of the profile 65 to its original state in this case, flexible elements can be attached in the profile area of the kink points, which support the uncurving after curving. The flexible elements can be integrated, for example, in the upper or lower sail.

By gathering mechanisms at the trailing edge of the profile, the camber or buckling is preferably transferred evenly over the span and the lift increase is thus increased.

Fig. 6 shows a kite 22 corresponding to Fig. 4 in a schematic representation, wherein elastic return elements 72, preferably rubber ropes, are arranged on the upper sail, which are anchored to the profile trailing edge 15 and ensure that the unloaded kite 22 returns to the contour shown in Fig. 4 with the S-shaped profile 65.

Fig. 7 shows a kite 22 corresponding to Fig. 5 with pulled brake lines 36, which is indicated by the arrow. The elastic rubber lines 72 are taut and the profile trailing edge 15 is curved downwards, so that the kite 22 as a whole has a curved profile skeleton line 66.
35

FLYGM02066 ''·''?·.''!! · 02/26/03

List of reference symbols

10 • »? &phgr;&phgr;&phgr;*&phgr;&phgr;
•&phgr;&phgr;&phgr;&phgr; φ·φ ? bar 11 * φ φ φ ? · · Profile nose 12 left control line 13 Wing tips 14 right control line 15 Profile trailing edge 18 Depower lines 20 Harness lines 22 Kite 24 Depower line 34 Safetyleach 36 Brake line 38 Middle line 40 left brake line 42 right brake line 44 Connection line 46 Connection line 48 Deflection device 50 Deflection device 52 Carrying straps, gallery lines 54 Pulley 58 rope 60 rope 62 Handle 64 Handle 65 Kite profile / S-stroke profile 66 Profile skeleton line 68 Nodding moment 70 Turning point 72 elastic return element 101 front carrying strap 102 rear carrying strap &phgr;&phgr;&phgr;&phgr;&phgr;&phgr;&phgr;&phgr;·&phgr;&phgr;&phgr;&phgr;
φ φ ? ? φ · ··· φ φ φ &phgr;&phgr;&phgr;&phgr;&phgr;&phgr; · φφφ

FLYGM02066 ·2··*. * ···*"··· 2 02/26/03

103 connecting line,

Limitation

104 V-line

105 Brake line

106 Depower top line

107 Stopper Ball

108 1st roll 108-2 2nd roll

109 Rings

110 Control line

111 Depower line

112 front bridle cords

113 rear bridle cords

120 bars

121 RKL

122 Safety line 12 5 Trimmer

301 Stop Ball

302 Stop Ball

Claims (14)

1. Kite with a line system for controlling the kite ( 22 ), characterized by a profile skeleton line ( 66 ) with an upwardly pointing profile trailing edge ( 15 ) when the lines are relaxed. 2. Kite according to claim 1, characterized by a curved profile of the kite ( 22 ) with a profile nose ( 11 ) and profile trailing edge ( 15 ) pointing downwards when the lines are under tension. 3. Kite according to claim 1 or 2, characterized in that the curvature or the profile of the kite ( 22 ) can be varied by a variable tension of the brake lines ( 36 ) anchored near the profile trailing edge ( 15 ). 4. Kite according to one of the preceding claims, characterized in that the curvature or the profile of the kite ( 22 ) can be varied by a variable tension of the control lines ( 12 , 14 ). 5. Kite according to one of the preceding claims, characterized by elastic return elements ( 72 ). 6. Kite according to the preceding claim, characterized by elastic return elements ( 72 ) anchored in the vicinity of the profile trailing edge ( 15 ) and in a central upper profile region. 7. Kite according to one of claims 1 to 4, characterized by an upper sail made of elastic material for producing an S-stroke profile ( 65 ) of the kite ( 22 ) in the relaxed state of the lines. 8. Kite according to one of claims 1 to 4, characterized by flexible elements in the region of a kink in the profile skeleton line. 9. Kite according to one of claims 1 to 4, characterized by at least one dynamic pressure opening and the skeleton line is at an angle of less than 50 degrees. 10. Kite according to one of the preceding claims, characterized by
a line system substantially symmetrical about the horizontal axis/depower line ( 111 );
a control line ( 110 ) which branches into a brake line ( 105 ) and a V-line ( 104 );
wherein the V-line ( 104 ) is deflected via a roller ( 108 ) and leads to the depower line ( 111 );
wherein the depower line ( 111 ) forks into the front risers ( 101 ) above the AB riser line or depower top line ( 106 );
wherein the roller ( 108 ) is connected to the rear carrying strap ( 102 ); and
wherein a connecting line ( 103 ) is provided between the front and rear carrying straps ( 101 and 102 respectively). 11. Kite according to one of the preceding claims, characterized by
a line system substantially symmetrical about the horizontal axis/depower line ( 111 );
a control line ( 110 ) which branches into a brake line ( 105 ) and a V-line ( 104 );
wherein the V-line ( 104 ) is redirected over a first pulley ( 108 ), then redirected over a second pulley ( 108-2 ) and then returned to the first pulley ( 108 ) or to a rear riser ( 102 );
wherein the first roller ( 108 ) is connected to the rear carrying strap ( 102 );
wherein the second pulley ( 108-2 ) is connected to the depower line ( 111 );
wherein the depower line ( 111 ) branches above the AB riser line or depower top line ( 106 ) into the front risers ( 101 ); and
wherein a connecting line ( 103 ) is provided between the front and rear carrying straps ( 101 and 102 respectively). 12. Kite according to one of the preceding claims, characterized by a brake line that can rotate freely around the control lines ( 110 ). 13. Kite according to one of the preceding claims, characterized by
a self-retracting safety line ( 122 );
wherein the safety line ( 122 ) together with the depower line ( 111 ) is guided through the bar ( 120 ) through a hole in the RKL ( 121 );
wherein the RKL ( 121 ) is connected to the control lines ( 110 ) via lines;
wherein a safety line ( 122 ) twisted around the depower line ( 111 ) can untwist itself again at the RKL ( 121 ); and
When the kite is only hanging on the safety line ( 122 ), the control lines ( 110 ) are shortened by a defined amount compared to the depower line ( 111 ). 14. Kite according to one of the preceding claims, characterized by a safety line ( 122 ) with which the length of the depower line ( 111 ) can be suddenly extended by a defined amount compared to the steerer lines ( 110 ), but the kiter still remains connected to the kite without the depower line being shortened again.