bow, Main and aft Tri-foil hydrofoil?

Discussion in 'Boat Design' started by Squidly-Diddly, Sep 1, 2020.

  1. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    How about a Tri-foil to increase redundancy and simplify altitude and stability, as well as putting more weight on a single efficient fully submerged Main center foil?

    Fully submerged is more efficient but requires fancy control to avoid disaster. "V" shaped surface intersecting are more self regulating but having the lifting foils pierce surface creates drag and decreases lift.

    So how about one big Main center fully submerged foil, then far forward and aft balancing foils? For some reason I'm thinking of a front "dumb" fixed (sturdy, cheap and first to take any hits) surface piercing foil and an active "smart"(sensing height after water surface has been processed constant factor by two previous foils) aft foil, but could be any combo of forward/aft foils.

    Idea would be that both control foils would have input and thus do better job at happy medium, and it wouldn't be as critical if a single control foil fails or gives bad feed back. An inline tripod.

    Side to side balance is another issue.
     
  2. Doug Halsey
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    Doug Halsey Senior Member

    Adding the V foils fore & aft would do nothing to help this.
     
  3. Squidly-Diddly
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    Squidly-Diddly Senior Member

    what would happen if you stuck a fully submerged foil in the middle of a Russian style hydrofoil with its fixed front and rear V or U foils? Wouldn't it still be balanced but think its less loaded, but with more drag? Ain't whole thing about V foils that they give more lift the deeper they are (or faster, but they will be going same speed on same boat) and are thus self regulating?
     
  4. upchurchmr
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    upchurchmr Senior Member

    You do know about the Dave Keiper hydrofoil that cruised the pacific with all those foils.
    For years.
    About the time he was setting up a company to manufacture them he died. DAK hydrofoils. See Wikepedia.
    The report was that there was so much drag, that he could not get lift off until around 12kts windspeed.
    Then he went faster than everyone, but was slower than everyone until he could get liftoff.

    Ancient history - somewhere around the 70's. Maybe late 60's.
     

  5. Squidly-Diddly
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    Squidly-Diddly Senior Member

    maybe I should mention that I was thinking of high-speed POWER hydro-foils where coming off the foils unexpectedly can be a disaster, and that tend to operate in wider range of waves for practical reasons, rather than sailing foils where just getting up on foils at all is considered great, and that can normally pick and chose when to operate.
     
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