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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 9:53 am 
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Its very simple: All we need are thinner tubes (at least half the diameter than now) and less belly in the sail.

First advantage: the the kite would have less drag.

Second advantage: the kite can eat the gusts better - you don´t have to power on...power off...power on...power off all the time.
Similar to a modern windsurfsail you would have to move it at the start, but once you have reached a certain speed it would generate constant pull. Even in gusts. No depower needed anymore. Power-on all the time. Means more speed.

Third advantage: You can use better boards if you have better kites. Current speedboards are built in the way they are because they must equalize the unconstant pull of the kite ! With constant pull you can use stiffer boards with more grip and longer and stiffer fins, because the gusts dont pull you over anymore. Means more speed.
(Reminds me of the development in windsurfing 30 years ago.)

Fourth advantage: If no depower is needed, it means less "work" at the bar for the average rider, too. So kiting becomes way easier - you just have to lean back and let the board go !
So its interesting for the whole kite industry.

Technically we just need more air pressure in the tubes to reduce diameter. So the tubes must be enforced - we need a completely new tube technology !

I hope in a few years we will only laugh (or vomit) at the big blown-up sausages we use now :rollgrin: :rollgrin: :rollgrin: :rollgrin:


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 11:50 am 
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Sebs kites allready have a much thinner L/E and are a lot flatter.
Image The Hydra is kindof where Bruno was heading before he got out of kite design.
Rob beat Seb by what 0.01 Kt on his switch so I'm thinking does the profile make that much difference? We may see in the next few weeks at Luderitz . Yesterday the Zeeko rider made 50+ kts in 25-30 so there is the 2x and thats on a standard Delta shape notus


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 12:38 pm 
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Maybe the cheapest source for tapered carbon for the LE of a kite would be a windsurf mast?

The top half of two of the 490cm Standard Diameter Masts bonded together would make a very light stiff spar which tapered to the ends of about 5m length.
http://www.north-windsurf.com/eng/nodes ... m-series-1

If they are using 9m kites or less the projected area is probably below 7m.

Reports from the kiters first windy day at Luderitz are quoting very high wind to board speed ratios.
That ratio is becoming more and more important and they are quoting a ratio even higher that the highest the windsurfers were quoting.

http://www.luderitz-speed.com/


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 1:01 pm 
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You can see the bend on masts here and by tensioning a line between the tips, even more bend could be induced - especially if a kite spar consisted of two mast top halves joined at the centre of the LE.

http://cdn.boards.mpora.com/wp-content/ ... action.jpg


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 3:44 pm 
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Quote:
You can see the bend on masts here and by tensioning a line between the tips, even more bend could be induced - especially if a kite spar consisted of two mast top halves joined at the centre of the LE.


here we go: no depower, thin leading edge, carbon reinforcement. fast design!
Image


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 3:49 pm 
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even thinner leading edge: Image
projected area almost equals full area of the kite.
still not a lot of depower.


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 3:59 pm 
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I would love to get a c-quad, they must have been real monsters at high speed.


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 4:16 pm 
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back to the roots...fantastic!

Anyone tried the old kites for speed yet?


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 4:44 pm 
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tilmann wrote:
Its very simple: All we need are thinner tubes (at least half the diameter than now) and less belly in the sail.

First advantage: the the kite would have less drag.

Second advantage: the kite can eat the gusts better - ...

Third advantage: You can use better boards if you have better kites. ...

Fourth advantage: If no depower is needed, it means less "work" at the bar ...

Technically we just need more air pressure in the tubes to reduce diameter. So the tubes must be enforced - we need a completely new tube technology !

I hope in a few years we will only laugh (or vomit) at the big blown-up sausages we use now :rollgrin: :rollgrin: :rollgrin: :rollgrin:



In Typical German engineering fashion ; i think you may have Nailed it !

Just noting the differences in my 2008 and 2010 Ozone Edge ; i see the correlation .
Both have 13M area, both have 7 struts, both have near the same profile ; the
difference is the 2008 Edge has a Smaller LE than the 2010, and the 2010 has
only 4-lines where-as the 2008 has 5. The difference between the two is Much the way
you describe ; the 08 is Faster, (even With the extra line), and it eats gusts Way better !!

The 2010 has Better PULL within it's speed-range however , or it has bin optimized
for a more specific but smaller speed-range.


The Only mistake you made is :
tilmann wrote:
Technically we just need more air pressure in the tubes to reduce diameter. So the tubes must be enforced -[b] we need a completely new tube technology !


The guy who fixed my PG, use to work for a company that did bladders of 20 to 30Lb
or better ; so the technology already exists. I'll ask him for a search request on Google,
that explained how it works, then post it.

I remember he said they'd Bend the tubes by strategically sewing in webbing on
one side.

The extra pressure Will make the tube more brittle on impact, (i think) ?

Bille


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 Post subject: Re: Back to the drawing board- how will we beat Sail Rocket?
PostPosted: Wed Dec 05, 2012 4:53 pm 
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I think there are lots of meat here for kite companies willing to innovate like the original players were forced to (since they had no one to copy back then)!

I've been wanting to make a high performance kite for some time (for both speed but more for improved upwind cruising on a raceboard or hydrofoil). I think the old C-quad design can be improved greatly in terms of depower by making it a more delta-C shape like the paraskiflex.
Image (from http://www.paraskiflex.com/produits/lx-serie/)

The paraskiflex has a different control bar set up to normal kites and is flown on shorter lines. I would change this to a normal set up.

Then I suspect that if you make a kite like this, and change the profile to a high performance aerofoil, the kite will most likely fly straight over your head, Hindenburg and fall on the ground upwind of you (if the drag is seriously reduced). The fat leading edge gives so much parasitic drag to kites that it is an easy way to make all the kites stable overhead. With this drag gone, you would either have to keep the kite powered up well when overhead so that induced drag and increased lift force will stop the kite over flying the wind window, or you would have to add a fifth line to add drag when you are not up to speed yet.

I think a mini fifth line is the way to go. It could be made to distort the aerofoil when pulled, allowing the kite to stay in the wind window while you get up to speed, and then once you are cruising you trim the fifth line so that the aerofoil straightens out and allows the extremely high L/D kite to pull you very fast.

I've been tempted to buy a paraskiflex and play with the bridle system to change it into a normal delta depower kite with long lines and normal bar set up.

Oh yes, my other reason wanting to try this sort of kite is for light wind. I think carbon spars are much lighter than inflatable struts with large pieces of dacron and PU. I think a kite like this would be even lighter than a deluxe flysurfer for its size even if made with regular fabric? By curving the kite like a detla shape (as opposed to a flatter C-quad shape) the stress on the leading edge spar is reduced and it can be made very light. Does anyone know the weight and size of a typical paraskiflex kite?


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