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Foils, foils and foils at race!!!

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Hansen Design
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Re: Foils, foils and foils at race!!!

Postby Hansen Design » Sat Aug 30, 2014 8:56 pm

Hagedoorn, Ultimate Sailing, Scientific American, March 1975. :thumb:
1975-03-05.jpg
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1975-03-06.jpg

ronnie
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Re: Foils, foils and foils at race!!!

Postby ronnie » Sun Aug 31, 2014 10:50 am

DrLightWind wrote:But it is only Damien, other than SeaGlider from France who are riding that. :wink:
It never became popular and accepted because it is expensive
and probably must have some disadvantages, just saying,

DrLightWind
The thing that is missing is the hydrofoil that keeps itself at a fixed depth. Where development is at now is that there is a foil which keeps itself at the same depth quite well on one tack.

Once that is sorted, I would expect the first application of this would be to take the outright wind powered water speed record back with a kite.

The relevance to this thread is that the ultimate development in kiting performance-wise may turn out to not be practical for racing or recreation.
So maybe racing on the current style planing raceboards or foils is where the racing line has to be drawn?

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Re: Foils, foils and foils at race!!!

Postby tomatkins » Sun Aug 31, 2014 3:31 pm

ronnie wrote:What if they develop pulling foils that are faster than the current push foils?

They may not even use boards at all - just the kite pulling on the foil with the rider somewhere in between.

Potentially lethal but the pinnacle of kite racing and the fastest wind-powered water craft of all.
Foil Boots?

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JS
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Re: Foils, foils and foils at race!!!

Postby JS » Sun Aug 31, 2014 7:06 pm

ronnie wrote:The thing that is missing is the hydrofoil that keeps itself at a fixed depth. Where development is at now is that there is a foil which keeps itself at the same depth quite well on one tack.
A curved surface-piercing foil, like an AC72 foil, maintains depth equilibrium when properly oriented.

ronnie
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Re: Foils, foils and foils at race!!!

Postby ronnie » Sun Aug 31, 2014 8:54 pm

JS wrote:
ronnie wrote:The thing that is missing is the hydrofoil that keeps itself at a fixed depth. Where development is at now is that there is a foil which keeps itself at the same depth quite well on one tack.
A curved surface-piercing foil, like an AC72 foil, maintains depth equilibrium when properly oriented.
The J foil has been used as in the Damien Leroy video, but I think a foil that keeps itself at a fixed depth would be a better solution. A more advanced version of this that works on both tacks.


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Hawaiis
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Re: Foils, foils and foils at race!!!

Postby Hawaiis » Sun Aug 31, 2014 10:17 pm

On no wind days this inflatable UAV can replace the kite.
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tautologies
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Re: Foils, foils and foils at race!!!

Postby tautologies » Mon Sep 01, 2014 1:35 am

Hansen Design wrote:Hagedoorn, Ultimate Sailing, Scientific American, March 1975. :thumb:
1975-03-05.jpg
1975-03-04.jpg
1975-03-06.jpg

Fantastic illustrations!!!

I can't help but think how insanely vulnerable the pilot is in this set up.... and how did we not get to kiteboarding until the 90s if this is a patent from the seventies.

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cglazier
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Re: Foils, foils and foils at race!!!

Postby cglazier » Mon Sep 01, 2014 3:17 am

Hansen Design wrote:Hagedoorn, Ultimate Sailing, Scientific American, March 1975.
Very interesting.. but..

It is not obvious to me why this would be any more efficient than our current kiteboard hydrofoil set ups. Clearly the foil underwater could be smaller and have less drag, but the foil in the air (the kite) has to be bigger and have more drag. Where is the benefit? Am I missing something?

:wink: CG

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tautologies
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Re: Foils, foils and foils at race!!!

Postby tautologies » Mon Sep 01, 2014 3:49 am

cglazier wrote:
It is not obvious to me why this would be any more efficient than our current kiteboard hydrofoil set ups.
Speculation:
The foil in the water can adjust automatically so that users does not make errors.

ronnie
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Re: Foils, foils and foils at race!!!

Postby ronnie » Mon Sep 01, 2014 8:22 am

cglazier wrote:
Hansen Design wrote:Hagedoorn, Ultimate Sailing, Scientific American, March 1975.
Very interesting.. but..

It is not obvious to me why this would be any more efficient than our current kiteboard hydrofoil set ups. Clearly the foil underwater could be smaller and have less drag, but the foil in the air (the kite) has to be bigger and have more drag. Where is the benefit? Am I missing something?

:wink: CG
Its to do with the power limit.
Currently the power is limited by the weight of the rider, the angle he can lean the foil over and therefore the height of the chop/waves.

With a submerged pulling foil, once the foil is moving, the foil can potentially hold enormous amounts of power and the riders weight becomes less important.

Its likely that the foil and kite would also have to be developed with a big range of power power/handling. I think the kite will be a lot easier to develop for that than the foil - especially if the hydrofoil power adjustment has to be automatic without using electronics.

I'm not suggesting pulling hydrofoils will take over, just that they will be the ultimate for powered performance in terms of speed and racing other than in light winds - and they are unlikely to be used in racing because of the danger.


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