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3D Kite Control Bar

In this page, we would like to introduce the 3D Kite Control Bar concept which is safer and more friendly to the unhooked riders.

The safety information on this page is not applicable to the new Flat LEI and only applied to the traditional LEI; however, the 3D bar concept is still useful for all unhooked riders.

Back Ground

The Chicken Loop was first "invented" and announced publicly on the Kitesurf group in August 1999, as described in the message   http://sports.groups.yahoo.com/group/kitesurf/message/4358.   As indicated in the "replied to" message, both Ken Winner (North) and Don Montague (kite designer for Naish) was still using the trim strap system to adjust the AOA of a 4 line inflatable kite (please note that the original 4 line control patent from Bruno has no chicken loop but require the kiter to permanently connect to the kite):

From:  Hung Vu <hungvu@n...>
Date:  Wed Aug 18, 1999  7:12 pm
Subject:  [ksurf] 4 line control bar for Wipika/Naish

Ken Winner wrote:
> If you want to set it up in a slightly different way you can get
> instantaneous depower. I find I can anticipate a gust by looking at the
> water and that a half second delay is close enough to instantaneous for me
> at the moment. Not to say I'm satisfied with my current setup. Always room
> for improvement.

If I were to convert my Wipika kite to a 4 liner, this is what I would
use for my set up to be able to instantaneously depower the kite. The
center line (the extension of the 2 front lines) will go THROUGH a hole
at the center of a straight control bar and connect to a "stopper" (a 5
cm long bar). The harness line is connected to the "stopper". I would
tune the lines such that the kite is in "full power" mode (similar to a
2 line mode) when the "stopper" is pulled against the control bar (the
"stopper" stops the center line from "escaping" from the control bar).
When I sail unhooked, I am always in full power. When I hook in, I can
just push the control bar away from me to depower (almost similar to
sheeting out in windsurfing).

Since the harness line is connected to the "stopper", I have a
"swiveling" harness line built-in. Furthermore, for safety release, I
only need a 1' or 2' rope attaching the harness line to my wrist or
harness. When I swivel the control bar, it will not affect the safety
leash. To activate the safety release, I just drop the control bar.

This set up would work for a Wipika/Naish 4 liner, may work for a C-Quad
and definitely will not work properly (the way it intends to) for a
foil.

> Don seemed to be stoked on the curved bar last fall, but uses a straight bar
> now with a cam-cleat in the middle for the main lines. Since the Naish kites
> don't work like conventional four-liners, with most of the tension on the
> main lines, the curved bar may not be the best solution. I suspect it
> requires too much attention. I used it, but didn't much care for it.

I suspected there must be a reason for it not becoming popular.

BTW, I guess most of the tension is on the front lines for most of the 4
liners.

Hung.

Since then, the Chicken Loop has gained more and more popularity and has became the "de factor" standard control system for most kitesurfing kites including foils (such as Flysurfer, Boom Vector, etc.) and Arc.

The Trap

While the Chicken Loop offers one of the most desirable capability in power kiting (the ability to instantaneously depowering the kite by changing its AOA) while still being able to ride unhooked, the original designer did not have a chance to extensively use and test it.  The Chicken Loop is DANGEROUS as it has a few fundamental safety flaws:

  1. In its default form (when the Chicken Loop is not used or hooked in), the whole system delivers maximum power.  This first design flaw encourages the users to use the Chicken Loop 100% of the time (otherwise they will be overpowered and won't have the depowering capability any more).  This bad habit is very dangerous as landing and launching hooking in is asking for trouble as any gust can send the kitesurfer toward dangerous hard objects on land.  This 100% hooking in habit is also dangerous on the water near shore or near hard objects as the kitesurfer can get dragged rapidly toward any hard objects on the water (boat, piers, reefs, rocks, posts, other water users, etc.) or onto land. In the recent serious/fatal accidents involving the Chicken Loop (in Cabarete and Texas), the kitesurfers were in the water near shore and was dragged on to land before the serious/fatal injury.  In comparison, most non-Chicken Loop riders normally unhook on land or when riding near shore or near hard objects.
  2. On the average, a Chicken Loop system needs around 16" to 18" range (less for smaller kites and more for larger kites) from the arm fully extended position (minimum power) to the arm compressed position (control bar very close to the body for maximum power).  To be able to accommodate this range universally, the Chicken Loop has to be very small so the kitesurfer can bring the bar very close to the body.  This is the second design flaw of the Chicken Loop system as such "arms compressed" position makes it very difficult to unhook (or even to hook in).  This "hard to hook in and to unhook"  further promotes the 100% hooking in habit.
  3. The third flaw with the Chicken Loop system is that it did not separate the safety system (the ability to unhook) from the depowering/empowering system. Worst of all, this flaw is also exaggerated by the first flaw such that to be able to unhook, one have to move the bar to the default state (maximum power state).  The combination of these flaws make it virtually impossible to unhook in powered up situation.

These three fundamental design flaws have been proven very dangerous as a number of incidents in the last few years have demonstrated.  Up to 2002 little has been done to address the danger of the Chicken Loop.  After a stern warning email from the original designer to the Kitesurf mailing list (to ban the use of the Chicken Loop for safety reasons),  many manufacturers have introduced quick release systems for their Chicken Loop systems (some other kitesurfers took a further step by bypassing the Chicken Loop and permanently connecting themselves to the kite via a quick release system).  While these quick release systems do attempt to solve the third flaw, they do not address the first two flaws.  By not addressing the first 2 flaws, they still promotes the bad habit of hooking-in (or shackling-in) 100% of the time.  "Ease of hooking-in and hooking-out" enables/encourages a non-Chicken Loop kitesurfer to ride unhooked in questionable situations (on land, near shore, near hard objects, boats, rocks, piers, posts, etc.). When bad things happen, the non-Chicken Loop kitesurfer simply "drop the bar".  A 100% in the Chicken Loop rider (or shackled rider) cannot get into that preventive position and has to "react" when bad things happen. Past accidents have shown that "reactive" mechanisms do not always work. Some examples of a quick release system failures are:

  1. The extreme load of the kite jams the quick release system
  2. Sand jams the quick release system
  3. Rusty quick release system gets jammed
  4. Quick release system gets frozen in very cold snowing weather (could happen frequently in kiteskiing and kitesnowboarding)
  5. Quick release system with strings that get tangled
  6. The activation mechanism of the quick release system cannot  be located or activated (it has moved to a more secluded position that is unreachable)
  7. The activation system of the quick release break down during use.
  8. A kiteskier/kitesnowboarder cannot activate the quick release system with the winter glove on
  9. Quick release system component fails under extreme load
  10. The quick release system fails due to unforeseen situations (such as the recent situations - January 2003 - in Cabarete where a kitesurfer failed to release his quick release system due to: "The snap shackle was DIRECTLY CONNECTED TO THE PLASTIC CHICKEN LOOP AND DIDN'T PROPERLY RELEASE").  Remember that we need at least 1 kitesurfing accident to learn about 1 new "unforeseen situation".
  11. And the list can go on and on...

To sum up, a quick release system is a very good idea; however, it should only be used as a BACK-UP and NOT AS A PRIMARY system.

Design Objectives

This page attempts to solve the Chicken Loop flaws by introducing 2 new instantaneous AOA control systems that have the following design objectives:

  1. Minimum power default state (if the system is not used, the kite will have minimum power).
  2. Easy to hook-in/unhook to encourage riding unhooked in questionable situations (on land, near shore, near hard objects, boats, rocks, piers, posts, etc.)
  3. Separation of the safety system and the depowering/empowering system (or activation of the safety system while in a minimum power state).
  4. More alternative safety systems (of different types: biological, mechanical, etc.) can be easily added.
  5. Offer same advantages as the Chicken Loop.
  6. Accommodate all or as much Chicken Loop riding styles as possible.
  7. Offer more features and incentives to attract kitesurfers to use the new systems instead of the Chicken Loop.

Before discussing the new systems, let's try to at least enhance the existing Chicken Loop system to make it safer.

Safer Chicken Loop

A safer chicken loop is the one that can address the fundamental flaws partially while still retaining most of the feature of the chicken loop.

A safer Chicken Loop is a larger Chicken Loop about the same size as the main loop.   While the Safer Chicken Loop (SCL) does not fully address all the flaws, it does partially address them:

  1. Flaw 1: The default form of the SCL is still maximum power; however, since the SCL limits the depowering/empowering range, so in practice, the default state should be somewhat "moderate power" instead of "maximum power".
  2. Flaw 2: The SCL addresses this flaw fully as the arm position to hook-in or unhook is fairly comfortable with the SCL.
  3. Flaw 3: The kitesurfer still have to empower the kite to be able to unhook; however, since the SCL limits the depowering/empowering range, in practice, the unhooking is difficult but may still be feasible in certain conditions.

So a SCL is not fully safe but definitely safer than the standard Chicken Loop as it may encourage the kitesurfer to ride unhooked in questionable situations (on land, near shore, near hard objects, boats, rocks, piers, posts, etc.).  The main disadvantage of a SCL is that it has limited range (around 2/3 of a standard Chicken Loop).  The other disadvantage of the SCL is that it makes the main harness line (the fixed loop or the main loop) harder to use and may be a bit inconvenient for a high-bar-load kites (or back lines flyer kites).  This may not be an issue as for 2003, most modern kites are front line flyers (or having multiple connection points allow one to make it more a back line or a front line flyer).

Some modern expert kitesurfers actually ride fully powered up with the minimum power setting of the Chicken Loop (arm fully extended).  This position facilitates one arm control of the kite (easier to control the kite one hand with the arm fully extended) to leave the other hand free for tricks (board grabbing, board off, etc.).  These riders use edging and the trim strap to control gusts similarly to non-Chicken Loop kiters and may pull the bar in occasionally to gain more power from the kite.  For those riders, the extended range of the standard Chicken Loop is not quite necessary and can benefit from the SCL without sacrificing much.

The Power Bar

The Power Bar is one of the 2 designs on this page that fully addresses the 3 fundamental safety flaws of the Chicken Loop and meet all the design objectives stated above.

Instead of adding a Chicken Loop (shown in red in the following diagrams) to a non-Chicken Loop set up, the Power Bar design adds a  single additional component, a Power Bar (shown in blue in the following diagrams).  The Power Bar are connected to the back lines (around 8" from the main bar) allowing one to adjust the power of the kite independently from the main bar (so therefore does not interfere with the hooking-in/hooking-out activities).  The kitesurfer can steer the kite using either the main bar or the Power Bar.  For modern front line flyer kites, the Power Bar will not take the full load of the kite and therefore can be made of very light material.

The following diagrams show the different power states of the Power Bar system versus the Chicken Loop system (for simplicity, we don't show the trim strap and the safety leash).  The Power Bar is shown of different length than the main bar for illustration purpose (the 2 bars can be of equal or much different lengths).  The Power Bar I systems uses the classic line connections and the Power Bar II system uses "pulley bar" line connections for shorter bar length and faster kite turning.

wpe13.jpg (27663 bytes)

wpe11.jpg (23472 bytes)

wpe12.jpg (26538 bytes)

Let's review the design objectives and see how the Power Bar system fits in:

  1. Minimum power default state:  when the Power Bar is not use, the kite delivers minimum power.
  2. Easy to hook-in/unhook to encourage riding unhooked in questionable situations (on land, near shore, near hard objects, boats, rocks, piers, posts, etc.): hooking-in and unhooking is as easy as a non-Chicken Loop system.  Furthermore, when the kitesurfer grabs the main bar (and release the Power Bar), the kite depowers (unless it was previously stalled) to allow even easier hooking-in and unhooking.
  3. Separation of the safety system and the depowering/empowering system (or activation of the safety system while in a minimum power state):  The main bar used for hooking-in and unhooking is separated from the Power Bar which is used for depowering/empowering the kite.  Furthermore, the kitesurfer hooks-in or unhooks while the kite is in minimum power state.
  4. More alternative safety system (of different types: biological, mechanical, etc.) can be easily added: A quick release system can be added on the main loop as a back up secondary safety device.
  5. Offer same advantages as the Chicken Loop:  The Power Bar system offers the same full range instantaneous AOA control of the kite.
  6. Accommodate all or as much Chicken Loop riding styles as possible:  The Power Bar system should accommodate most (if not all) Chicken Loop riding styles.
  7. Offer more features and incentives to attract kitesurfers to use the new systems instead of the Chicken Loop:  The Power Bar system offers a few more features and incentives as follows:
    • For a low-bar-load kite, the weight of the Power Bar can be tuned accordingly to offer automatic AOA control (similar to "automatic reefing" of the modern windsurfing sail).  If this is tuned properly, one may not ever want to use today's manual AOA control again.
    • Similarly, the connection between the main bar and the Power bar can be made of some elastic material to offer automatic AOA control.  This can be used independently or together with the weight of the bar.
    • A "pulley bar" line connection on the main bar can be used for shorter bar length and faster kite turning.  This type of connection also makes it easier to grab the main bar at the center (necessary for certain tricks).
    • The Power Bar system facilitates launching and landing unhook (for kites such as the Arc which may require instantaneous AOA control while launching - as claimed by some on the Kitesurf mailing list, the Power Bar system could also be used; however, it may be a bit awkward at first.  The system described in the next section may be more suitable for that purpose.).
    • Due to the ease of hooking in and unhooking, the Power Bar system allows the kitesurfer to perform both hooking-in tricks as well as non-hooking-in tricks.
    • Due to the ease of hooking in and unhooking, the Power Bar encourages the good habit of riding unhook near shore or near hard objects.
    • The Power Bar is not attached to the front lines as the main bar in a Chicken Loop system and therefore has more degree of freedom (allowing for 3D movement of the bar).

How To Make a "Prototype" Power Bar

Adding a Power Bar to you non-Chicken Loop set up is very easy:

  1. Buy a 1/2" to 3/4" diameter (thinner for front line flyer and thicker for back line flyer) wooden rod from Home Depot (around $2) and cut it to the same length as your main bar. 
  2. Drill 1 hole (same thickness as your back leader lines) at each end of the new Power Bar.
  3. Make a knot on each back leader line around 8" from the main bar.
  4. Slide the 2 back leader lines through the holes at the end of the new Power Bar.

Voila, you now have a Power Bar on your existing set up (you can also tie a knot on the back leader lines just above the Power Bar just to make sure that it won't slide away from you - unlikely in most conditions).

Riding With a Power Bar

We made a Power Bar System II set up and managed to tried it on 3 back line flyer kites: AR5 11.5, AR5 5.5 and Black Tip 4.4 (we wanted to try it on the Ocean Rodeo and the Arc but the wind was too strong for the sizes we have).  The main bar and the Power Bar are very short around 18 - 20".  Here are some of our observations:

  1. Either the main bar or the Power Bar could steer the kite very well (even for the 11.5 with such a short bar length).  The kite was more responsive with the Power Bar.
  2. The ends of the "^" line in the "pulley bar" configuration kept on touching our hands in this prototype.  A production system should move those line-ends away from the kitesurfer's hand.
  3. In the maximum power position, the Power Bar felt heavier with the AR5 than the Black Tip (could be due to the differences in size).  The Power Bar system should work better with a front line flyer kite in such case.
  4. We kitesnowboarded with the Power Bar set up and the  everything worked out well.
  5. We found that the main bar did not interfering much with the rider when not in use (could be due to such short length)
  6. When not in use, the Power Bar did not interfere with the rider at all.
  7. We find that the "^" lines in the "pulley bar" configuration was a bit "jerky" when steering the kite.  We move the knots closer to center of the "^" line and the "jerkiness" reduced.
  8. We did not have a line winder and found that we could wind the two bars closer together and then wind the lines between the 2 bars.

To sum up, the Power Bar II set up worked, the empowering/depowering worked as well as the Chicken Loop and the main bar did not interfere much with the rider when not in use.

Power Bar Safety Comparison

The following table shows a comparison of the safety options of a shackled-in rider, a Chicken Loop rider, a SCL Rider and a Power Bar rider (or non-Chicken Loop rider):

Rider Type Get into preventive positions (unhooked when launching and landing on land or when riding near shore or hard objects) Unhook in case of emergency Use of quick release systems in case of emergency
Shackled-in Rider Potentially on land (need some elaborated procedure). No when riding. No Yes
Chicken Loop Rider Potentially on land (need some elaborated procedure). Very difficult when riding. Very Difficult Yes
SCL Rider Potentially Potentially Yes
Power Bar Rider (or non-Chicken Loop rider) Yes Yes Yes

"Yes" in the above means that the system supports and/or encourages the use of such device/procedure. 

"Potential" means that the system supports and/or encourages with some degree of difficulty and/or extra efforts.

"No" means that the system does not support such use.

The 3D Bar

One of the major draw back of the "Power Bar" design is that it needs 2 bars instead of 1 bar.  2 bars may create line tangle during setup and kiting.

The obvious enhancement to the "Power Bar" concept is to make 2 bars in to 1 bar, a 3D bar.

The simplest form of a 3D bar is a "rectangle bar" (the bar is a rectangle).

A more complex form of 3D bars are multiple bars interconnected on both sides via a triangle (for 3 bars), a square (for 4 bars), a pentagon (for 5 bars), etc.

The back lines are connected to 1 bar and the front lines are connected to another.

Each bar in a 3D bar has a designated kite AOA associated with it.

By grabbing on any bar in a 3D bar, one can select the associated AOA of the kite.  One can change the AOA of the kite (without hooking in) by grabbing another bar.

By hooking into one bar, one can adjust the AOA of the kite by grabbing and pulling on any other bar.

 

 


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