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An idea for depower below the bar.

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ronnie
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An idea for depower below the bar.

Postby ronnie » Fri Jul 11, 2008 1:19 pm

One of the problems is what to do with the extra rope when you depower. This idea has the rope running round the chickenloop, which is a U-section ring. By turning a thumbwheel, you wind a narrower diameter rope onto a pulley. This thin rope pulls more of the powerline around the chickenloop ring, thereby depowering the kite. A toothed cam locks the thin line to a line guide. To release the depower, you turn the thumbwheel to take the tension off the cam then hold the cam open with your thumb and release the thumbwheel while some line runs out. releasing the cam stops the unwinding.
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DEPOWER.jpg

tungsten222
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Re: An idea for depower below the bar.

Postby tungsten222 » Fri Jul 11, 2008 1:31 pm

bis repetita non placent.
Last edited by tungsten222 on Wed Feb 03, 2010 4:16 pm, edited 1 time in total.

ronnie
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Re: An idea for depower below the bar.

Postby ronnie » Fri Jul 11, 2008 1:56 pm

The best option is a spreader bar with a quick-release hook. The depower would require a ring about 7 cm in diameter and if you add 15cm for the max length of powerline between the ring and a Q/R you get to 25cm, which is maybe workable. The diagram is not actual scale for each item, just an illustration.

Ideally it would be used with a spreader bar with a quick release hook and the donkey dick would be mounted on the spreader bar. The kite would be using something like the Cabrinha IDS except there would only be the powerline and it would only have the push-through stopper and a stopperball for when the kite was fully flagged out 5th line style, so it would be very clean above the bar. To depower, you turn the knob. To release the depower, you twist the knob to release the cam, then hold the cam open. Admittedly you only have precise control when depowering. A strap system gives a bit more contol of letting the depower off.
It's possible that the knob could be used as a brake when releasing the depower.

BWD
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Re: An idea for depower below the bar.

Postby BWD » Sat Jul 12, 2008 5:06 pm

Bungy inside a tube -verry NICE!
for windsurf uphauls at least. Question: for depower rope, can you reach it easily when it retracts? hmmm, I think it would be good for below the bar...

fiddly bits =Not so MUCH....
- how to fiddle them when banging through chop overpowered?
- cost to build?
- cleaning and maintenance?
- durability: line diameter = chafe protection and longevity
- quick release achieved with more mechanisms, weight and cost on releaseable spreader bar = classic widening design spiral. But keep working on it, there is potential. Just need to overcome the "centrifugal force" of the design spiral.

Nice thing about a big old rope, is you can grab it mid-wipeout and maybe get dragged less (but it's still gonna hurt :wink: ) Mechanically it seems a cool invention, but I'd use a simpler design.

ronnie
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Re: An idea for depower below the bar.

Postby ronnie » Sun Jul 13, 2008 8:43 am

BWD wrote:Bungy inside a tube -verry NICE!
for windsurf uphauls at least. Question: for depower rope, can you reach it easily when it retracts? hmmm, I think it would be good for below the bar...

fiddly bits =Not so MUCH....
- how to fiddle them when banging through chop overpowered?
- cost to build?
- cleaning and maintenance?
- durability: line diameter = chafe protection and longevity
- quick release achieved with more mechanisms, weight and cost on releaseable spreader bar = classic widening design spiral. But keep working on it, there is potential. Just need to overcome the "centrifugal force" of the design spiral.

Nice thing about a big old rope, is you can grab it mid-wipeout and maybe get dragged less (but it's still gonna hurt :wink: ) Mechanically it seems a cool invention, but I'd use a simpler design.

Hi BWD,
I think it would be easier to turn a knob on the chickenloop than to reach for and grab the correct depower ball above the bar and pull on more depower.

Durability would be an issue, but the replacements would probably be of the powerline and the thinner extension to it. This system would also require a moveable push-through stopper - like the Starkites one.

It has pulleys and a cam, so there are issues of - would it continue to work well and how much maintenance would it need?

The spreader bar would be simple to maKe and you are saving the cost of the Q/R that the hinged hook replaces. You also save, in the case of an IDS system, the costs of the depower straps and the depower line through the bar, and the chickenloop with quickrelease.

If there was a KISS solution to make more breakthroughs, I think someone would have thought of them by now. Usually now, you gain something somewhere and lose something somewhere else, except for kite design, where it's still a bit of a black art.

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klimber
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Re: An idea for depower below the bar.

Postby klimber » Mon Jul 14, 2008 5:45 pm

the friction between the rope and your rign is going to be too great to mearly spin with your thumb. IMO

tungsten222
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Re: An idea for depower below the bar.

Postby tungsten222 » Mon Jul 14, 2008 8:01 pm

bis repetita non placent.
Last edited by tungsten222 on Wed Feb 03, 2010 4:17 pm, edited 1 time in total.

BWD
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Re: An idea for depower below the bar.

Postby BWD » Mon Jul 14, 2008 11:08 pm

Yes well but what if your uhh "donkey" gets 'is "thing" caught in the toothed wheel?
= donkey sausage :oops: -all in fun.

More serious questions:

Could a finger get caught in this mechanism that carries the whole load of the kite?

In the picture the line appears routed so the part wound by the thumbwheel runs past the standing part of the line (part going up twd kite). This looks like it could foul in a slack line situation. Could it?

What's done to prevent overrides on the drum that the line is wound up on?

Would it be better to wind a strap than a line?

Could the thumbwheel itself foul the standing part of the line? Looks close in the sketch.

Maybe you have thought of all this stuff and more.

Sorry to be such a critic, I am in the middle of designing and building a small boat now and every component I design, I find I am looking for the most robust, cheapest and lightest (when I can afford it) solution. Which usually also means the simplest. It is often a copy of some idea that has been around forever, but the payoff is it's more likely to work and usually takes less time to build. And sometimes you don't have to do as much math!
So I have grudgingly come to have more respect for KISS than before...

If you have a pull-pull system with balls to grab, maybe that's the problem. Your idea could be a great solution, but so could replacing the pull-pull rig with an old fashioned ladderlock push-pull strap or a rope and cleat system. No solution fits everybody.
I do think the idea has potential, but marketability might be elusive given the need for a new QR spreader bar to go with each unit. Slingshot charge over $100 for theirs....
Anyway, show some pics if you make one. Be cool to see it.

ronnie
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Re: An idea for depower below the bar.

Postby ronnie » Tue Jul 15, 2008 10:14 am

Hi BWD,
This diagram was just to illustrate the idea. A product engineer would look at all those aspects when designing a production model.
The friction around the ring is a valid point - as mentioned above.
The Slingshot spreader bar has a spinning leash (I have one). There would only need to be a hook which was hinged at the top of the hook and a spring-loaded pin as the release. Simple and a lot cheaper.
The strap is one option. The cam clamps against a line guide as I said, because of the variation of the line winding on the thumbwheel.The slack line could come off the ring, but a couple of loops on the ring, or a tube may fix that. A slight brake effect on the thumbwheel would help stop it creating slack line.

I am a fan of KISS. I usually try to start with a blank sheet of paper and try to come up with the simplest solution. This idea may seem complicated, but I think it looks better when you look at the bar system as a whole and see how much it replaces. Depower is an area where I think improvements can still be made.

I have only owned Cab kites recently and am awaiting a 13m IDS Xbow. Their depower system is good. The stopper on the IDS not so good, so I hope there s a free retro-upgrade when they sort out the problem.


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