Lifting Spinnakers:does it lift the bow?

Discussion in 'Sailboats' started by Doug Lord, Nov 24, 2006.

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

    Doug Lord Flight Ready

    This is an asymetrical section(from skywalk site) kite shown in the orientation it would have on a performance boat.The top and bottom of the kite as shown would be supported entirely differently than shown and the lines going to the center of the kite wouldn't be necessary. Since the kite is an asymetrical wing the problem is how to use it on opposite gybes:
     

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  2. bistros

    bistros Previous Member

    Again, Doug you are completely off base and substituting conjecture for facts. The middle suspension lines are critical to maintaining the airfoil. I've been suspended under a similar inflatable foil section hundreds of times and if the middle lines were removed, I would not be walking (or alive) today. An inflatable airfoil section section works because of evenly spaced lateral shroud lines, even in orientations such as in the picture you show. Each vertical cell wall in the inflated foil needs a suspension line to control it's placement.

    In a inflated foil section, the full width of shroud lines provide the same function as mast track or luff wire in a sail - without a luff rope, a main sail would not work, and without a rigid forestay and hanks or internal luff wire, a jib would not be effective. Just attaching head and foot (tack & clew) would not work.

    If you doubt this, please refer to Dan Gardiner's reference work "The Parachute Rig", to understand the issues with inflatable wing sections. I was a FAI-licensed Rigger "A" for parachute reserve packing and equipment design and maintenance during my years of skydiving.

    --
    Bill

    PS

    If you want to learn more about this, either go across Florida to Zephyrhills (north of Tampa - a major skydiving Mecca) or up the coast to Deland (the other major dropzone in Florida. I've spent weeks there and there are people there who will happily explain inflatable wing theory to you.
     
  3. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    The whole subject IS conjecture-is this kind of a thing possible or not? You say no without fully understanding the implementation that may be possible.
    I've spent many hours watching kiteboards up close and I think something along these lines MIGHT work....
    It is obvious to me that the shape of the kite is directly influenced by the direction of pull of the lines-my idea is based on having the support lines support the ends entirely differently than the way the ends are supported as a kite.
    Perhaps using the 4 line "C" design with mods necessary to produce an asymetrical section gybe to gybe.

    http://www.kiteboardingevolution.com/kiteboarding-kite.html
     
  4. Munter
    Joined: Jul 2007
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    Location: Australia

    Munter Amateur

    Doug - you've just re-invented Peter Lynn's kite design! (sort of)

    Get googling for details.
     
  5. ned
    Joined: Apr 2010
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    Location: New Zealand

    ned Junior Member

    gennakers deffanatly lift the bow.
     

  6. Munter
    Joined: Jul 2007
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    Location: Australia

    Munter Amateur

    Ok. Well I guess that's the end of the discussion then.
     
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