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Lofting danger!

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  • Hung Vu
    I got my first serious lofting experience today and fortunately in the water so I was very calm and observed all the facts to report it here. 1- The wind was
    Message 1 of 4 , Jun 21, 2004
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      I got my first serious lofting experience today and fortunately in the
      water so I was very calm and observed all the facts to report it here.

      1- The wind was very gusty probably from 10 to 30 knots.
      2- I was struggling to trying to come back to the beach (a very narrow
      section of the beach around 200' or so)
      3- The gust came unexpectly and lift me 20' in the air and probably 50'
      down wind

      My observation:

      Forget about trying to unhook or "pulling on something", lofting happens
      so fast that I AM NOW VERY SURE that only "dropping the bar" MAY
      (probably 40% to 50% "MAY") work.

      P.S., I was using a GlobeRider 12m and a small custom board.

      P.P.S., This is not tea-bagging as tea-bagging only on lift 5' or so.

      P.P.P.S., It was fun in the water but I bet it would not be so fun on
      land...

      Hung.
    • DeniseSEWA@Aol.com
      In a message dated 6/21/2004 4:34:54 PM US Mountain Standard Time, hungvu2000@rogers.com writes: Forget about trying to unhook or pulling on something ,
      Message 2 of 4 , Jun 21, 2004
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        In a message dated 6/21/2004 4:34:54 PM US Mountain Standard Time,
        hungvu2000@... writes:
        Forget about trying to unhook or "pulling on something", lofting happens
        so fast that I AM NOW VERY SURE that only "dropping the bar" MAY
        (probably 40% to 50% "MAY") work.

        .

        P.P.P.S., It was fun in the water but I bet it would not be so fun on
        land...

        Hung.
        A week ago I was launching my 4 meter Ekko ( Extreem buggy foil) getting
        ready to do some buggying, wind was maybe 5kts when suddenly I was caught in a
        "dust devil" and lofted instantly, even with handles instead of a bar and very
        sensitive brakes it happened so friggen fast there was nothing I could do but
        let go and hit the ground, lump on the head, very sore ribs and no skin on my
        shoulder was the result, Had it been in the water with a bar and one of my water
        kites it probably would have been fun but you are right that there was no way
        I could have pulled a shackle, I think the only time it is usefull is if you
        are getting dragged rather than lofted.I wear a depower leash in the water but
        very glad I didnt have one on the Ekko, would have been alot worse.
        glad you came out of your experience unhurt.
        Denise

        http://hometown.aol.com/denisesewa/index.html


        [Non-text portions of this message have been removed]
      • George Sarris
        In my opinion 10kts with gusts to 30kts is too extreme. We must remember that the lift on an airfoil increases exponentially to the wind speed. The formula for
        Message 3 of 4 , Jun 22, 2004
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          In my opinion 10kts with gusts to 30kts is too
          extreme. We must remember that the lift on an airfoil
          increases exponentially to the wind speed.

          The formula for Lift is:
          Lift = � ( 1.2 * Area * Coeff of lift * Wind
          Speed(squared) ).

          Assuming a coeff of lift of 1.0, using 9m projected
          for a 12m flat area kite, the lift would increase from
          143 newtons (or 15kg force) at 10kts wind speed to
          1,286 newtons(or 131kg force) at 30kts wind speed.
          This is almost a factor of 10 times the lift or force
          on the kite.
          --- Hung Vu <hungvu2000@...> wrote:
          > I got my first serious lofting experience today and
          > fortunately in the
          > water so I was very calm and observed all the facts
          > to report it here.
          >
          > 1- The wind was very gusty probably from 10 to 30
          > knots.
          > 2- I was struggling to trying to come back to the
          > beach (a very narrow
          > section of the beach around 200' or so)
          > 3- The gust came unexpectly and lift me 20' in the
          > air and probably 50'
          > down wind
          >
          > My observation:
          >
          > Forget about trying to unhook or "pulling on
          > something", lofting happens
          > so fast that I AM NOW VERY SURE that only "dropping
          > the bar" MAY
          > (probably 40% to 50% "MAY") work.
          >
          > P.S., I was using a GlobeRider 12m and a small
          > custom board.
          >
          > P.P.S., This is not tea-bagging as tea-bagging only
          > on lift 5' or so.
          >
          > P.P.P.S., It was fun in the water but I bet it would
          > not be so fun on
          > land...
          >
          > Hung.
          >
          >
          >
          >




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        • Kite Power (Sydney)
          Hi George Thanks for posting that calculation, it should be part of every instructor course, should also be part of every kiteboarding lesson, and should be
          Message 4 of 4 , Jun 22, 2004
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            Hi George
            Thanks for posting that calculation, it should be part of every instructor
            course, should also be part of every kiteboarding lesson, and should be
            tattooed on every experienced riders forehead.
            Especially people from a non power kiting background like wakeboarding,
            windsurfing, etc, they have no idea about this LAW of physics.

            Cya and
            Goodwinds
            Steve McCormack
            www.kitepower.com.au



            ----- Original Message -----
            From: "George Sarris" <jakefarley2000@...>
            To: <ksurfschool@yahoogroups.com>
            Sent: Wednesday, June 23, 2004 5:03 AM
            Subject: Re: [ksurfschool] Lofting danger!


            > In my opinion 10kts with gusts to 30kts is too
            > extreme. We must remember that the lift on an airfoil
            > increases exponentially to the wind speed.
            >
            > The formula for Lift is:
            > Lift = ½ ( 1.2 * Area * Coeff of lift * Wind
            > Speed(squared) ).
            >
            > Assuming a coeff of lift of 1.0, using 9m projected
            > for a 12m flat area kite, the lift would increase from
            > 143 newtons (or 15kg force) at 10kts wind speed to
            > 1,286 newtons(or 131kg force) at 30kts wind speed.
            > This is almost a factor of 10 times the lift or force
            > on the kite.
            > --- Hung Vu <hungvu2000@...> wrote:
            > > I got my first serious lofting experience today and
            > > fortunately in the
            > > water so I was very calm and observed all the facts
            > > to report it here.
            > >
            > > 1- The wind was very gusty probably from 10 to 30
            > > knots.
            > > 2- I was struggling to trying to come back to the
            > > beach (a very narrow
            > > section of the beach around 200' or so)
            > > 3- The gust came unexpectly and lift me 20' in the
            > > air and probably 50'
            > > down wind
            > >
            > > My observation:
            > >
            > > Forget about trying to unhook or "pulling on
            > > something", lofting happens
            > > so fast that I AM NOW VERY SURE that only "dropping
            > > the bar" MAY
            > > (probably 40% to 50% "MAY") work.
            > >
            > > P.S., I was using a GlobeRider 12m and a small
            > > custom board.
            > >
            > > P.P.S., This is not tea-bagging as tea-bagging only
            > > on lift 5' or so.
            > >
            > > P.P.P.S., It was fun in the water but I bet it would
            > > not be so fun on
            > > land...
            > >
            > > Hung.
            > >
            > >
            > >
            > >
            >
            >
            >
            >
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