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[a-w-h] Air403 and flutter stall

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  • Claus Nybroe
    Ken talks about wind turbine noise, when the turbine idles just before cutting in and when the wind changes direction. For most turbines I quite agree that you
    Message 1 of 2 , Feb 1 12:27 AM
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      Ken talks about wind turbine noise, when the turbine idles just before
      cutting in and when the wind changes direction. For most turbines I
      quite agree that you can easily learn to live with these noises, in fact
      you can start missing them, when they are not there anymore. These
      noises are very different from the noise of flutter stall, which for
      instance characterizes the Air models.

      Flutter stall appears at high wind speeds making the blade move rapidly
      back and forth around the center line.

      Flutter stall is VERY noisy. Dave talks about nervous horses, Graham
      about unhappy neighbors and I can tell about one of my old Windflower
      prototypes getting into a runaway resulting in blade flutter stall. The
      windows in a cow stable a couple of hundred meters away started to
      vibrate at high frequency, making the cows afraid and very hard to
      control. Angry farmer.

      Flutter stall reduces revolutions of the rotor, and I assume the Air
      turbines uses this method for speed control in order to get the price
      down. Flutter stall gives you speed control for free being already built
      into the construction. You do not have to add extra technology in order
      to provide speed control by a furling tail, blade pitch or rotor tilt.

      I know flutter stall very well, and it is most painful to the ear. In
      fact I consider it unhealthy. I am against too many regulations, but
      this should be prohibited. A real wind turbine should always operate
      below non-hazardous dB levels, and as such I can I can only see the Air
      as a low cost compromise. Sorry Andy. I do recognize your work for
      building an industry, and I expect you are working on solving this
      problem in future models. No more on this subject from me.
      --
      Claus Nybroe
      http://www.windmission.dk
      Denmark
    • georges
      ... Nah, he only listens to his engineers, and they swear they can t hear a thing anymore:)
      Message 2 of 2 , Jan 23, 2001
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        --- In awea-wind-home@egroups.com, Claus Nybroe <windmission@v...>
        wrote:
        > Flutter stall is VERY noisy. ...
        > I expect you are working on solving this problem in future models...

        Nah, he only listens to his engineers, and they swear they can't hear
        a thing anymore:)
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