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Twin Tip Hydrofoil

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ronnie
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Re: Twin Tip Hydrofoil

Postby ronnie » Tue Dec 22, 2009 5:59 pm

I think this shows that the foil is not the problem. The problem is having enough control from the way you connect to it.


föhn
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Re: Twin Tip Hydrofoil

Postby föhn » Wed Dec 23, 2009 2:12 am

DART VADER wrote:I love my FOILBOARD
Image



Hy D.V..
with what size & type of kite are you sailing on this day?
Thanks
F.

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ed257
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Re: Twin Tip Hydrofoil

Postby ed257 » Wed Dec 23, 2009 4:48 am

I started this thread and like the idea of a twin-tip, bi-directional hydrofoil. If it works.

I also like that the design does not need water at least 4 feet deep to ride (some of our spots can be shallow at times). And you should be able to attach it to your twin tip when you want to ride in foil mode and detach it when you don't.

The inventor contacted me and said he is finalizing the design and will soon be going into production.

Time will tell.

Ed

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JS
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Re: Twin Tip Hydrofoil

Postby JS » Wed Dec 23, 2009 6:47 am

ed257 wrote:I started this thread and like the idea of a twin-tip, bi-directional hydrofoil...

I like it too. But it seems to me that a twin tip foil could get away with much less foil and structure. There's a lot of wetted surface, not least the longitudinals. I visualize a horizontal foil at each end, each probably less than 20" long, and each mounted by a pair uprights.

Obviously bi-directional foils can't be as efficient as unidirectional, but I still think an optimized setup would perform very well. A stiff board would be important, especially to avoid those longitudinals. On the other hand, a bit of flex would probably be good to increase the AOA on the leading foil (relative to the rear) in order to better carve turns and respond to waves. In steady state, I guess a variation in AOA between front and rear of a few degrees or so might yield the right blend of performance and vertical stability.

Cheers,
James

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ed257
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Re: Twin Tip Hydrofoil

Postby ed257 » Sun Jun 06, 2010 2:24 am

ed257 wrote:I started this thread and like the idea of a twin-tip, bi-directional hydrofoil. If it works.

I also like that the design does not need water at least 4 feet deep to ride (some of our spots can be shallow at times). And you should be able to attach it to your twin tip when you want to ride in foil mode and detach it when you don't.

The inventor contacted me and said he is finalizing the design and will soon be going into production.

Time will tell.

Ed


I contacted the designer and am waiting to hear from him. I will advise this board when I do.

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chemosavi
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Re: Twin Tip Hydrofoil

Postby chemosavi » Sun Jun 06, 2010 3:42 am

That's weird Ed. I haven't gotten any messages from you. In all seriousness I made a dual hydrofoil board around 4 or 5 years ago and posted it on this forum. Also loaned it to Armin of FS. And spoke to the ceo of Ocean Rodeo. I did not patent it because it had more problems than I was willing to solve at the time. Good luck to whoever picked up the idea off of my posts or dreamed it up on their own. Not that big a stretch really. It's just kind of strange when somebody claims it was their idea to begin with when maybe it wadn't. Pardi on...............

longwhitecloud
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Re: Twin Tip Hydrofoil

Postby longwhitecloud » Sun Jun 06, 2010 6:14 am

upwind angle is insane in light moderate
you learn quick not to fall off your giant lure lol

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discojuggernaut
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Re: Twin Tip Hydrofoil

Postby discojuggernaut » Sun Jun 06, 2010 7:31 pm

chemosavi wrote:That's weird Ed. I haven't gotten any messages from you. In all seriousness I made a dual hydrofoil board around 4 or 5 years ago and posted it on this forum. Also loaned it to Armin of FS. And spoke to the ceo of Ocean Rodeo. I did not patent it because it had more problems than I was willing to solve at the time. Good luck to whoever picked up the idea off of my posts or dreamed it up on their own. Not that big a stretch really. It's just kind of strange when somebody claims it was their idea to begin with when maybe it wadn't. Pardi on...............


This one?
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chemosavi
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Re: Twin Tip Hydrofoil

Postby chemosavi » Sun Jun 06, 2010 9:05 pm

That's it. On one of FS's boards. They didn't like it because I put too much curve in the foil shape and at any speed it got whacky. Once you got past 15 or so knots it wouldn't stay in the water easily.

There was another guy on Foilzone named Rabid or something who said he had some luck with a dual foily affair around the same time I was working on this.

I also talked on the phone with Rich Miller (sailboard hydrofoil) about patents and what not and he said after he'd invested 10 grand on his he reflected he wouldn't do it again because he realized nobody "really" wanted to go that fast on a sailboard.

Maybe folks are bored enough with the status quo now to look for new thrills or maybe they want to win races; whatever the case it's good to see the interest.

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Re: Twin Tip Hydrofoil

Postby edt » Fri Jul 16, 2010 4:40 pm

chemosavi wrote:That's it. On one of FS's boards. They didn't like it because I put too much curve in the foil shape and at any speed it got whacky. Once you got past 15 or so knots it wouldn't stay in the water easily.




Chemosavi, correct me if I'm wrong, but for gear weighing between 150 and 250, going at speeds of 20 mph you will want approximately 20 square inches of area completely underwater and also you will want the edges to penetrate the water at approximately 45 degrees.

It looks to me that once that foil reaches speed, the only part in the water will be a small bit of the curve, and it will be almost completely flat. At a guess you have around 140 inches worth of foil there, when you should have 40. If you make your foil three times thinner won't that solve the problem of stability at high speeds?

The reason I'm asking is because I'm sure you've tried all kinds of things, and wonder what the results were.

I'm planning on building my own twin tip hydrofoils this summer myself.


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