Longshot trifoiler

[bcv99]

Seems like there are some new designs aiming speed sailing record based on hydrofoils, like e.g. Sylphe, Absolute Wind Records and Project Dared. Information can be found here.

Absolute Wind Records, Project Dared (scroll down):
http://foils.wordpress.com/

Projekt Sylphe:
http://www.ecole-navale.fr/fr/irenav...4/A4Sylphe.pdf

These approaches are probably inspired by the recent success of Hydroptere.

Does anyone have some more information on those very interesting projects? What do you think of the approaches? Is the hydrofoil development (the latest research work seems to be focused in France) so far progressed that a new attempt for the absolute speed record is possible? Will they use supercavitating foils? Or maybe swept supcavitation one?

Really curious what you think about that!

cheers, Bernd

[tspeer]

I'm really surprised that none of the foilers seem to recognize the need for sweep. It could significantly extend the range of subcavitating operation.

Like this, Tom?

http://www.boatdesign.net/forums/att...3&d=1181717587
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See posts 9,18,23 and 24 for more on the designer and boat.
Ultimate 18' Tri ?

[tspeer]

Yes, but with more taper and a higher aspect ratio.

[TTS]

Originally Posted by Doug Lord

Bernd, you may find this interesting; it is from the A class mail list and mentions a speed sailing prototype being built in the US by a Team I haven't heard of before:

"Hi Jeremy!
It has been a year since your e-mail, but we have only now gotten in a position to buy a used A-Cat, and perhaps you never found a buyer for your boat.
The price and condition of your boat seem satisfactory, but we are in New Jersey so shipping might be unacceptably expensive. Sometimes items like this can be piggybacked on a moving van shipment if they can be disassembled to reduce the size for shipment.
It is also unclear exactly how appropriate the boat would be for our purposes so I will explain what we are trying to do and hope that you can send us photos if the boat is still available.
We are developing new techniques for speed sailing which we hope to test on a modified A-Cat. Specifically we will mount a sailcloth airfoil between the mast and the bow, and another smaller one aft of the trampoline. These are predicted to the lift the boat off the water at true wind speeds above 15 knots and should result in boat speeds in excess of 30 knots. We need a boat which can be modified so that the hulls are on center lines twelve feet apart and which is constructed in such a way that it is possible to attach mounting fixtures for our airfoils. We hope to keep the weight of the modified boat below 200 pounds.
Please let us know if your boat is still available or if you know of a boat which we might obtain.
Thanks.
Cheers,
Jay Eveleth, Kittihawk20 Speed Sailing Team"

Doug,

What I can add to this is that Jay took possession of a modified and rebuilt Waterat A-Class from me on 7-13-2007 for use in this project. Conceptually it is an interesting approach, but I think it will take some time to work out the inherent bugs in the design and approach. One of the issues that will come up is probably a hobby horsing effect with forward and rear airfoils competing against each other for stability. Beyond that I can not say more, but those interested in the project or who think they might want to assist him can reach him at is email XYPTX@aol.com

Tom

Thanks, Tom!