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  1. #15
    Senior Member Navegante's Avatar
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    Quote Originally Posted by boards_ronnie View Post
    Yes! After the foils dominating in 2013 and looked like they were dominating in 2014, out came Alex (World kite speed record holder at 56+ knots) and whupped everyone on his speed crossing race board.

    So the jury is still out on what is the fastest across the wind.

    http://translate.google.co.uk/transl...an&prev=search

    I think gybes will be doable without touching down once the equipment is a bit more developed. Foils can be turned quite tightly, so momentum could keep it foiling through a gybe.

    This guy seems to think the duck gybe is the solution.
    https://www.youtube.com/watch?v=x6QOG2gNq0g

    The kite foils are still developing at a rate.
    Currently the rear wing is upside down on most foils to help steady things when the board is tilted nose up or down. Because the foil is 1 metre away from the board, the centre of uplift would tend to move too far forward if the nose was raised. Having the rear wing upside down counteracts that a bit and makes it easier to keep everything balanced.
    I think there may be a possibility that they could have two positive lift wings in a canard configuration, but we shall have to wait and see when the development reaches the limits.

    Certainly a foil-specific board like the AHD could be developed. The kite foil boards tend to be about 160 by 52 by 7cm with deep double concaves under the nose and chamfers on the rails - but they vary a lot in design.
    interesting what you Say. I had a good look at one of the earlier versions of these foils for windsurf.
    A couple of week ends back. A guy was practicing on one. No brand displayed on the thing but
    it seemed to me that the angle of the mast/shaft could point a bit further forwards and at the same time the wing assembly angle to it would need to be adjusted to keep it parallel to the board planing surface to balance the ride. This would eliminate to an extent the need for a dedicated board with a further forward fin slot or a board with two fin slots like I mentioned earlier.
    The issue would be finding out how much stress a stock board fin box could take.

  2. #16
    Senior Member Navegante's Avatar
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    However, if the foil assembly is efficient and a light wind range determined then it looks like any rig would make it go.
    https://vimeo.com/118694777

  3. #17
    Quote Originally Posted by boards_ronnie View Post
    This is the Defi Kite run last year in light winds. They are fairly fast across the wind in light conditions.
    https://vimeo.com/96567004

    In 2013 in strong wind the best kite foilers beat those on kite race boards across the wind. The guy in green with the yellow board won.
    https://vimeo.com/75228119
    In the triangle race scene in SF reguiar kite race boards have all but disappeared: hydrofoils have a much better upwind and down wind angles and they dominated the fleet when it was still mixed.

    Speedwise my understanding is that kites on racing hydrofoils reach in the upper 20s (tops around 27). That is slowish, any slalom board can go faster, and explains how I can actually pass hydrofoils (maybe not top racers) just on FSW equipment.

    Low end looks impressive, but again it does not look much better than guys on Formula or big windsurfing gear. To be honest I am not even sure why a hydrofoil should have better low end, kite or windsurf. A different and fun experience, yes, but why the contraption should be better than a finned board in low winds has never been clear to me and it felt a bit like marketing. On the beach comparisons are made even harder because people have started using up to 20 square meters kites on hydro: of course they take off early!

    Things will evolve fast (especially in Kiting) and the new north hydrofoil is quite exciting in design. Still I wonder if hydrofoil are doing to kites what course racing and Formula gear did to windsurf: scare off a lot of people. If you look at the North the thing is very expensive (3000 Euro!), bigger than a windsurf (the foil is 100 cm long) and sure looks more complex!
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by duzzi; 25th April 2015 at 04:01 PM.

  4. #18
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    Current foiling boards use inverted T foils. Problem with these is their quite limited speed range. They need to be big enough to get board planing ( out the water) at a relatively low speed. If they don't drag will be such they never do,hence quite a large ( again relatively) large foil which will give too much drag ( and lift) at high speeds,consequently although low wind performance fantastic top speed will still not compete with normal boards.
    Foiling cats ( and hydroptere) get around this by using constant lift( diminishing drag) angled foils. ( with a small inverted T on rudder). As craft goes faster foil lifts further out the water , presenting less area and hence constant liift, allowing craft to go faster and faster. ( hydroptere 50 kts plus in 25 kts wind) These type of craft utilise a development of "Bruce" foils, where windward foil actually produces negative lift ,opposing heeling forces. The leeward foil and inverted T on the rudder providing positive lift. Clever bit is fact these craft can tack( or gybe) sail on new tack and without changing angles of foils the lift automatically " swaps" sides. ( because of leeway). This system has inherent problems for windsurfers, boards are not subject to healing forces. Years ago Mistral ( and others) tried only to find windward rail sinking with increased speed. Change angles and leeward rail suffers same fate. A couple of companies are working on getting a similar system to work. If interested google " Bruce Foils" for better explanation of what's going on in foiling cats. ( foiling moths use a completely different system more akin to AHD system)

  5. #19
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    A video on the North foil.
    Interesting bit is the bit about the two tuttle boxes. The forward one for the usual kite foils and the North high performance foil and the rear box for the North foil he is using in the video.

    https://www.youtube.com/watch?v=BoWClt-2WIg

  6. #20
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    This video either means the kite foil is as fast as slalom race boards or the windsurfers are going slow so he can film them.

    https://www.youtube.com/watch?v=gQQpMq2zz9A

  7. #21
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    The wind looks light and the windsurfers are on big slalom boards.....and oversheeting a good part of the part.........they are certainly not "on it"!

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