Home grown Laser Hydrofoils

Discussion in 'Sailboats' started by Kevin Charles Rissell, Aug 1, 2019.

  1. Kevin Charles Rissell
    Joined: Aug 2019
    Posts: 21
    Likes: 7, Points: 3
    Location: Oakland, MD, USA

    Kevin Charles Rissell Junior Member

    There's been the idea of having the controlling foil in the front of the boat with the "wand" controlling the angle of a forward bow foil, allowing the rudder to just be a rudder (Necessarily deeper than normal for a dingy that a foil has been added on to).

    I'm going with the (1) layer of kevlar approach to provide a smooth top surface front to back, on my second version of foils, and applying the curved Mylar gap seals to the bottom of the foilfs. Thanks for the suggestion, and pointing me in the right direction on this.

  2. rnlock
    Joined: Aug 2016
    Posts: 72
    Likes: 4, Points: 8, Legacy Rep: 10
    Location: Massachusetts

    rnlock Junior Member

    I think your new foils should have 10 or 20 percent more span and chord, which I expect would make take offs happen at a significantly lower speed. While you're at it, you might taper the new foils. Maybe the tip chord should be about half tne root chord. This will help a little with induced drag and a lot with structural issues. You won't need as much carbon in the spar. As I recall, the Decavitator human powered hydrofoil had a big wing and a little wing. The big wing made take off easier and allowed the boat to pick up some speed. Then the big wing retracted and the little wing did the whole job. This was easier because only the canard chamged pitch, controlled by skimmers. I'm guessing the system on Moths might be more efficient, though.

    I think your foils may have a lot of intersection drag. You might consider wing fillets, as on airplanes. Part of the fillets should extend downstream in a little "stinger".

    BTW, I'm impressed that you could make this work.
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