iFoil

Discussion in 'Sailboats' started by Doug Lord, May 15, 2015.

  1. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    This is a hydrofoil board that has been in development for a few years. It uses a foil invented by Jon Howes which is a surface running foil: http://www.ifoil.co.uk/
     
  2. ch3oh
    Joined: Mar 2015
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    Location: fin

    ch3oh Junior Member

    Looks really draggy. Maybe the foils are for getting the LEDs up?
     
  3. Jon Howes
    Joined: Jun 2004
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    Location: UK

    Jon Howes Insomniac- sleep? Wassat?

    Just a flying visit: It looks draggy if you put all that in the water at once. You don't. It balances a bit like a unicycle on the large span foil, the forward and aft foil provide "feel" references to the rider to keep close to optimum incidence. Contact of trim surfaces is therefore intermittent and trim drag is negligible.

    Most the the main foil is not wetted when foiling as about 50% of the upper surface is ventilated as a minimum, as you go faster this actually reduces. Lift off lift coefficient is very high (about 1.2) but staged ventilation of the aft upper surface reduces this with acceleration to a running value of 0.2, reducing further as surface running speed increases.

    Induced drag is low due to the large span, and therefore low span loading.

    Nett result is that we have had some top sailors trialling it (for example Nick Dempsey amongst others). They have all had "nerve" issues when powering it up, it taking some time to build confidence in control to do this. It is very fast indeed, it also goes to windward much more effectively than a conventional board, even when not foil-borne.

    Don't take my word for it. If you can get to Weymouth on the UK south coast, contact Linton (+44 1305 823726) and have a go.

    Jon
     
  4. Jon Howes
    Joined: Jun 2004
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    Location: UK

    Jon Howes Insomniac- sleep? Wassat?

    Forgot to mention, the shape of the board is a reduction to just what is needed for foil and rig support and to act as a launch platform. It is a bouyant, planing, tunnel hull with an integral "bowsprit" (for want of a better description) on which is placed the mast step. Its requirements are low aerodynamic drag, low aerodynamic pitching moment and aerodynamic centre as far back as possible to avoid uncontrollable pitch diversions at speed.
     
  5. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    iFoil / Tomahawk

    Glad to hear from you ,Jon! The board looks real good. Has anyone done any more with the Tomahawk dinghy?

    Pictures-Tomahawk dinghy and Jons foils. These foils are so cool because ,among other things, they don't require an altitude control system like a wand:
     

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  6. Jon Howes
    Joined: Jun 2004
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    Location: UK

    Jon Howes Insomniac- sleep? Wassat?

    Hi Doug,
    We have not progressed the dinghy at this stage as the foils are much better suited to a windsurfer application, particularly the longitudinal balance method that was worked up for boards, which would be more difficult (but not impossible) on a dinghy.

    The dinghy was still in danger of having a submerged aft foil on the rudder which meant most of the advantages of the ventilated lift foil were lost as, unlike the lift foil, the submerged foil still had all the usual advers cavitation/ventilation reactions.

    If the market builds OK for the windsurfer we do have further plans, but lets wait and see.

    Jon
     
  7. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    iFoil+

    I wish you the best of luck ,Jon. Sticking with it is key and you sure as hell are doing that-you deserve great success!
     
  8. sigurd
    Joined: Jun 2004
    Posts: 827
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    Location: norway

    sigurd Pompuous Pangolin

    Nice board! I especially commend the rounded edge on the fore skid. Do you plan to make more of a funboard as well, or is the width of the foil making the board too stiff to slather around? I'm just saying that because of the way you have the straps set up, what class of board is it akin to? I mean, slalom boards are fast, freeride boards are slow slalom boards, and wave boards and freestyle boards are fun. Where are the specs? Volume, span? I'm on a mobile, might have missed it. Super kudos for this (and the rubber band orni and the monofoil).
     
  9. Jon Howes
    Joined: Jun 2004
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    Location: UK

    Jon Howes Insomniac- sleep? Wassat?

    Hi Sigurd,

    The foiling board is not really aimed at any existing board sector, it's an entity in its own right. It has been technically extremely successful and the board shape is optimised for foil-borne sailing, its displacement performance is of secondary importance only so we put the wide platform aft to allow a vector from the riders cg, through his feet, to intersect the centre of the foil.

    Steering is rig-dominated with no board in the water and it is sailed a bit like riding a uni-cycle, the front and rear stabilisers are barely in water contact providing only tactile feedback in the case of the front foil and powerful pitch-up if the main foil is dived excessively. It's also wave tolerant as its a ventilated foil (that I designed for Monofoil originally). Everyone who has sailed it has been blown away by how easy it is as well as how quick.

    Commercially it has been a flop so far as windsurfing is effectively dead. The marketing could have been performed much better and the name, iFoil, is just plain embarrassing, none of this being my doing. Don't get me started on those ridiculous LEDs....... Major lesson learned from this and other enterprises is that the next one will be run solely by me and my very capable wife. Too much good IP chucked away on the wrong people! It isn't going to happen again.

    Regards,

    Jon
     

  10. sigurd
    Joined: Jun 2004
    Posts: 827
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    Location: norway

    sigurd Pompuous Pangolin

    Hehe leds, yea, like on the cool stuff you can get on a well stocked gas station.
    You said rig dominated control, thats how the boring boards work. Like, old school longboards that were used for regatta and ... I don't know, i recall drinking coffee and eating cake while sailing one.
    Nowadays you can get longboards that feel like sailing a shortboard in slow motion. I tried one for the first time today, a kona one. It carves and stuff.

    I'm sorry it has flopped so far, going to look into whether anyone reviewed it. Odd that windsurfing should be dying, the stuff they make now is so much better than what it was before. Like downhilling on a city bike, that's what the gear was like in the 80's. All kinds of insane ideas like slalom boards with wave shapes, 'short'boards with two rear straps after each other, prevailed. It's almost as if they hadn't read the specifications for the human race before they finished some of these designs. I'm being flippant, I'm grateful to those guys of course.
    Hope to try the foilboard of yours, best wishes.
     
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