Flapping inverting foil (patent pending)

Discussion in 'Boat Design' started by frogger1225, Sep 7, 2014.

  1. wavepropulsion
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    wavepropulsion Pirate Member

    So, send me one if you have in blue, at least you improved the fan, summer is coming in south hemisphere.
    Beginners in the use of sculling oars (hydrofoils that use the water lifting effect), use it more flexible as suggested by the experts, then when they aquire some expertise reinforce the loom by fiberglassing to be more rigid and efficient: the faster you move the harder is the water.
    I don't say your work not worth the effort, just is not as efficient as you claim for serious rowing. And less efficient where the water is not quiet, and the winds blow.
    As I say before this have a market, I suppose, so good luck, ever is wellcomed somebody doing an effort for improvements.
     
  2. daiquiri
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    daiquiri Engineering and Design

    Not that one, of course. That video shows your oar used for a body exercise, which can be a good idea too.

    I was referring to this video: https://www.youtube.com/watch?v=yoQ-A8KzZvk#t=13 where you are trying to use oars for propulsion. But the biggest part of your power there is used to overcome the lateral drag, and very little transformed into propulsive thrust. In fact, your "Frogtoon" is barely moving forward: https://www.youtube.com/watch?v=oJil5zJlmM8&feature=youtu.be
     
  3. wavepropulsion
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    wavepropulsion Pirate Member

    Right. Cause this a single sculling oar interacts better with the hull and forces.
     
  4. wavepropulsion
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    wavepropulsion Pirate Member

    [​IMG]

    This is the more efficient sculling oar, and Douglas Martin have a name not for nothing. It flexes as Ben Fuller explains but not at blade level, but the loom. The better thing for BF for small boats as gunning floats in protected waters. Nothing new under the sun.
    Asians was testing for centuryes, and if flexible and vertical blade is better, they still using already, but is not. Trial and error.
     
  5. myark
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    myark Senior Member

    I received an email one hour ago from an Government official for important information, strangely his name is Mr Froggett.
     
  6. rwatson
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    rwatson Senior Member

    Originally Posted by rwatson
    Your optimism is commendable, but I would take odds on it ever being successful, if you can arrange a bookmaker.


    ....... he wagers his soul without fear, confidently boasting he is "the best that's ever been."


    So, its a golden violin as the stakes ???
     
  7. daiquiri
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    daiquiri Engineering and Design

    All this is reflected in the design of modern scuba fins, which have pretty much affinity with sculling oars. At the beginning their blades were just little more than simple flexible rubber pads, which would bend along the whole length during the power stroke.

    Over the time, though, the evolution has made them become pretty complex shapes. Modern fins have rigid structures (girders? :) ) placed along the lateral edges and a flexible membrane connecting them in between. The root is very flexible today, and all the bending is concentrated in that area. It is shown pretty clearly in this video by Mares: https://www.youtube.com/watch?v=Pc2wD6ULwzI
    The extreme version of this concept is this Scubapro fin: http://www.scubapro.com/fins/products/seawing-nova.aspx

    The advantage comes from the fact that the flexible root allows the pushing pressure difference to be distributed over a bigger area. It gives more thrust for the same pressure, or a smaller induced drag for the same applied stroke power.

    Cheers
     

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  8. wavepropulsion
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    wavepropulsion Pirate Member

    Thanks for the video and the post DAIQUIRI. The blade of the oar I posted looks may be as a shark tail.
    Ken Upton, engineer from England,observes the dolphins has more speed than allowed for their muscles and he did a great research. He still using wave energy now to generate electricity. First works was based in fish tails, he founds a canard shape is the better, more or less as the fins for scuba.
     
  9. daiquiri
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    daiquiri Engineering and Design

    Perhaps he wanted to say - more speed than allowed by our mathematical models.
    Because dolphins evidently have exactly the speed allowed by their muscles. ;)
     
  10. wavepropulsion
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    wavepropulsion Pirate Member

    Dolphins uses the power of waves to gain speed,in coordination with their muscles.
     
  11. daiquiri
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    daiquiri Engineering and Design

    Power in = power out. Nothing comes for free. ;)
    Cheers
     
  12. wavepropulsion
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    wavepropulsion Pirate Member

  13. wavepropulsion
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    wavepropulsion Pirate Member

    Yes power in of muscles + power in of waves. Cheers mate.
     
  14. wavepropulsion
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    wavepropulsion Pirate Member

    Bose and Lien -1990- demonstrated numeracally that an inmature fin whale, Balaenoptera physalus, swimmint at 2.5m/s in a fully developed seaway corresponding to a wind speed of 20 knots, could potentially absorb between 25 and 33% of its required propulsive power in head and following seas respectively through its horizontal tail flukes. Such potential wave energy absorption has significant consequences for the energetics of cetacean migrations.
     

  15. portacruise
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    portacruise Senior Member

    Yes, but using a good design gives you more speed for that power out- by using the proper leverage, as an example.

    PC
     
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