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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Sat Oct 24, 2009 4:27 pm 
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Peter_Frank wrote:
The weight of the kites are interesting in other respects, but for "light wind" perfomance, I cant see any relevance whatsoever !

You and your kiteboard and kite weigh around 85 to 90kg in average.

So a difference of a few kg's wont make any noticable difference at all !

If you are talking about relaunching and dynamic performance when turned around hard, it is another issue - but we are talking about light wind performance only, right ?

I am 100% sure that the mass wont make much difference, regarding KITING in light wind.

Of course, if we are talking about how low you can go with a kite, flown on LAND only, the mass is of real importance, true :thumb:

Kindly, Peter Frank


yep, plus the minute you addd piliot control into the factor the pull of the kite becomes variable, Just cuz your wing lufts the best(really what weight to surface ratio means) doesnt mean it flys the best or makes the most pull? What about line length and stroke speed? There is just to much also involed with the wing shape a delta shape and a paraglider shape are going to do such different things while moving that weight and lift ratio are out the door........

If you are kiting under 10k then thats great have fun and go kiting, if you are argueeing that any kite flys better in low winds becuase of the lift to mass ratio then you really need to go kiting and stop quessing what wind you can go kiting in.

I used to work for a snow board company that had two engineers from the flight comunity in it, thoose two bozo messed up the board shapes so badly based on the Computer models, CAD work etc. I went out and in one week did all the same work it took them a year to do by just riding and changing shapes, go figue they cost the company millions I was a 1500 hundred a month saleried rider.... And that years shapes came from my RD

Go figure.


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Sun Oct 25, 2009 3:13 am 
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Here is a recipe for light wind kites from Bill Hanson,
I was asking in an other thread (I hope he wouldn't mind quoting) couple of months ago:

Hansen Aerosports wrote:
Besides speed and power through the turns, the definition of success for a light-air kite
is the ability to generate lift at the edge of the window which is determined
by a combination of induced, surface and form drag.
For a given area and form, the light air equation ultimately is dominated by weight
which expresses itself as induced drag from the portion of available lift needed to support it.

A lightweight thin-tubed single surface 'C' kite has as much potential to do this
as a bulkier SLE or foil with bridles.
PS of course any kite may generate more lift through turns (sines or kiteloops),
but always at the expense of upwind ability.
I design kites of all types and the quest for light air performance is an interesting pursuit.
Promoting one type over another is unproductive. Understanding them is.
BILL


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Sun Oct 25, 2009 9:04 pm 
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list updated!
we have a new "winner"! the cooper ultra light (very beautiful kite, by the way).
the lynn c-quad got a respectable third place! thanks alot jakemoore, for the data!(projected area estimated by choosing 0.85 as mean proj. factor for bridled kites) also added: pkd buster II. it lands in the middle field.


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Oct 26, 2009 2:23 am 
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Location: Vancouver
herculon wrote:
The weight per projected area of a kite might be one plausible indicator of the light wind performance of a kite...

Thanks for this interesting and informative thread.

I agree that this is a useful indicator for expected light wind performance - especially very light wind performance. Of course, it's only meaningful if the kites are otherwise well optimized designs.

Aspect ratio and all kinds of other paramaters could also be introduced, but at some point it's more representative to measure various kites' actual performance, head to head.

It's kind of like car magazines. They often quote max horsepower, power/weight, and so on. But in the end, it's of little use to have the car with the best power/weight ratio if another car with a lesser ratio manages to outperform it, due to a myriad of other design considerations.

Again, great thread,
James


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Oct 26, 2009 11:33 am 
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@JS: yes, you are right. this weight per qm is only interesting in the lightest of the wind conditions.
see the naish helix: certainly not light wind gear, but if in good enough wind, imho its a fantastic kite with superior stability and max depower.

what i am a bit wondering about is the zephyr. it really should have been lighter! but if other design aspects make him a lightwind kite, be it so.


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Oct 26, 2009 5:43 pm 
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In this whole weight discussion thing there's one kite brand that can be used to get a good idea of the difference. As far as I know flysurfer is the only kite company that makes exactly the same shapes in two different fabrics.

The Speed 3 15m
Standard 3,56kg
Delux 2,54kg

I have riden both the Delux and Standard versions of the Speed 2 15m and there is a significant gain in low end "forgiveness", way better lull survival, easier relaunch and a nimbler feeling in the kite.

If a LEI for example a Zephyr were to have the same kind of weight gain it would go from 5kg about 3.7kg.

Try putting a kg or two of weights on a kite and you'll see how bad it flys.

Also keep in mind that after a dunk in the water weight becomes very critical, even more so with light wind riding. If your kite is on the heavy side to start with the odds are against you.


Last edited by FredBGG on Mon Oct 26, 2009 6:15 pm, edited 1 time in total.

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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Oct 26, 2009 6:06 pm 
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FredBGG wrote:
The Speed 3 15m
Standard 3,56kg
Delux 2,54kg

If a LEI for example a Zephyr were to have the same kind of weight gain it would go from 5kg about 4.7kg.


aren't it more like 3.6kg?

3.56 * 71.35% = 2.54kg

5* 71.35% = 3.6kg


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Oct 26, 2009 6:16 pm 
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Ismo wrote:
FredBGG wrote:
The Speed 3 15m
Standard 3,56kg
Delux 2,54kg

If a LEI for example a Zephyr were to have the same kind of weight gain it would go from 5kg about 4.7kg.


aren't it more like 3.6kg?

3.56 * 71.35% = 2.54kg

5* 71.35% = 3.6kg


oops typing error... thanks


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Thu Oct 29, 2009 2:35 pm 
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just to show you whats technically possible:

[url="http://www.flyozone.com/paragliders/en/products/gliders/ultralite/specifications/"]Ozone ULTRALITE Paraglider[/url].

Code:
+----------------------------+------+-------+------+------+-------+----+
| Ozone ULTRALITE Paragl. 09 | 23.0 | 20.16 | 0.88 | 2.85 | 0.141 |    |
+----------------------------+------+-------+------+------+-------+----+


its not a kitesurf kite, i know. but you can imagine that it would possible to build ultralite kitesurf kites. also, as those paragliders are certified, the material should be strong enough for kitesurfing, too.

Image

Materialien:
Top Surface : Skytex36 / Skytex 27
Bottom Surface : Skytex 27
Ribs : Skytex 40 Hard

i think this example raises the bar for thy flysurfer RD team! lets see if they introduce an ultralite deluxe^2 option :)

price tag for the ozone ultralite is around 1.990 euro - not that much more than a flysurfer speed III...


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 Post subject: Re: weight / projected area = onepossible light wind indicator
PostPosted: Mon Nov 02, 2009 10:23 pm 
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new data:

Code:
+----------------------------+------+-------+------+------+-------+----+
| Ozone light XC 2009        | 14.0 |  9.8* | 0.7  | 3.1  | 0.316 |    |
+----------------------------+------+-------+------+------+-------+----+


lightest "non-monster" tube kite yet. strange thing is that the ozone light is lighter than the zephyr per proj. sqm.

is it all about marketing hype with the zephyr? would you be better off buying a ozone light XC ?


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