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Re: [pop-pop-steamboats] Not sure

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  • David Halfpenny
    Message 1 of 6 , Sep 2 4:51 PM
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      ----- Original Message -----
      From: "Frank McNeill"
      > The last search turned up something at http://tinyurl.com/2342fk about
      > a method for generating vortex rings that might have changed history
      > if James Rumsey had known about it.
      He probably did know about it, since Gentlemen have been blowing smoke
      rings over their sherry for centuries. But he may not have picked up on the
      link to propulsion.
      David 1/2d
      non-smoker, non-drinker


    • Pete B.
      Frank, The vortex rings that you mention are similar to the vortex at the end of the wings on aircraft. The addition of winglets minimize the effect of the
      Message 2 of 6 , Sep 2 5:40 PM
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        Frank,

        The vortex rings that you mention are similar to the vortex at the end of the wings on aircraft. The addition of winglets minimize the effect of the vortex rings.

        Blended Winglets

        Pete


        --- In pop-pop-steamboats@yahoogroups.com, "Frank McNeill" <frankmcneilll@...> wrote:
        >
        > Hi, Jean-Yves, Pete, Carl and all,
        >
        > I have also seen something about that elusive boat with a pop-pop
        > boiler made of barrel heads and have searched for it several times
        > with no results.
        > The last search turned up something at http://tinyurl.com/2342fk about
        > a method for generating vortex rings that might have changed history
        > if James Rumsey had known about it. For a connection between vortex
        > rings and propulsion Google for squids.
        >
        > Best wishes to all, old Frank
        >

      • Frank McNeill
        Hi Pete, Similar maybe, but with opposite effects. Vortices from rigid wings generate drag. Vortices from flapping wings generate lift. Go to
        Message 3 of 6 , Sep 2 10:53 PM
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          Hi Pete,

          Similar maybe, but with opposite effects. Vortices from rigid wings
          generate drag. Vortices from flapping wings generate lift.
          Go to http://tinyurl.com/379eb2 for "Against All Odds: How Bugs Take
          Wing" and to http://tinyurl.com/ys85lf for "Optimal' vortex rings and
          aquatic propulsion mechanisms."

          Best wishes, Frank



          --- In pop-pop-steamboats@yahoogroups.com, "Pete B." <georgeyyy@...>
          wrote:
          >
          >
          > Frank,
          >
          > The vortex rings that you mention are similar to the vortex at the end
          > of the wings on aircraft. The addition of winglets minimize the effect
          > of the vortex rings.
          >
          > [Blended Winglets]
          >
          > Pete
          >
          >
          > --- In pop-pop-steamboats@yahoogroups.com, "Frank McNeill"
          > <frankmcneilll@> wrote:
          > >
          > > Hi, Jean-Yves, Pete, Carl and all,
          > >
          > > I have also seen something about that elusive boat with a pop-pop
          > > boiler made of barrel heads and have searched for it several times
          > > with no results.
          > > The last search turned up something at http://tinyurl.com/2342fk about
          > > a method for generating vortex rings that might have changed history
          > > if James Rumsey had known about it. For a connection between vortex
          > > rings and propulsion Google for squids.
          > >
          > > Best wishes to all, old Frank
          > >
          >
        • David Halfpenny
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          Message 4 of 6 , Sep 3 2:22 AM
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            ----- Original Message -----
            From: "Pete B."
            The vortex rings that you mention are similar to the vortex at the end
            of the wings on aircraft. The addition of winglets minimize the effect
            of the vortex rings.
            The crucial difference is that vortices impede a soaring creature but
            enable a swimming one.
            It's obvious that squid swim and eagles (with their winglet feathers) soar.
            What isn't obvious is that insects swim though the air ( hence the old joke
            about "according to the laws of aerodynamics a bumblebee is unable to fly,
            but fortunately nobody has told the bee").
            And that little birds chop and change. I caught a sparrow in my house last
            week and took it out of doors in a bucket. It flew straight up vertically
            like a helicopter (swimming) before gliding across the street (soaring).
            I suppose this is wandering off topic so I'll stop before we get on to
            propellers . . . ;-)
            David 1/2d






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          • Pete B.
            Hi David & Frank, It s fascinating how Science can contradict itself. In the case of vortices the configuration and dynamics determine whether they are a help
            Message 5 of 6 , Sep 3 5:23 AM
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              Hi David & Frank,

              It's fascinating how Science can contradict itself. In the case of vortices the configuration and dynamics determine whether they are a help or a hinderance.

              I was unaware of that phenomenon. Who said that you can't teach an old dog new tricks? How do bumblebees fly? What about hummingbirds? I watched 3 fly around flowers yesterday. It's amazing that they are able to maintain the wind speed that they do.

              Thanks for the contributions.

              Pete

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