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Laddermill- novel windmill design

  1. Nov 11, 2006 #1
  2. jcsd
  3. Nov 11, 2006 #2

    Danger

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    It looks intriguing, but I can't load the movie to see how it works. The still pictures seem to show a system that doesn't actually do anything. How does the loop connect to the ground? I don't see any pulleys or anything.
     
  4. Nov 11, 2006 #3

    turbo

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    The movie (all 11.7Mb of it) doesn't show much either, though I gather from reading the web site that the "mill" is a long string of kite-like planes that will be controlled from the ground and made to climb and dive in unison. It appears that the tether will be wrapped around some kind of shaft with a resistive load attached, so that the "pumping" action of the kites can be translated into a rotation that can drive a generator or something similar. It could be a neat way to pump water in a remote location without hauling in motorized pumps, fuel, etc.
     
  5. Nov 11, 2006 #4

    Danger

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    I can foresee some awesome work needed to synchronize all of the individual lift factors.
     
  6. Nov 11, 2006 #5

    turbo

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    It may be something as simple as designing inflatable kites that lift when inflated to a certain pressure and dive when the pressure is reduced. Taking altitude-dependent external air pressure into account could easily be as simple as installing orifices at a number of locations along the string to gradually reduce the pressure delivered to the next-higher group of kites. The pressure (and lift coefficient) of inflatable kites could be computer-controlled, or perhaps even automatically controlled mechanically by valves that are actuated at the desired limit of retraction and extension of the tether. There are a lot of ways to skin that particular cat. Depending on the lift generated by each kite the upper tethers can be very thin and lightweight, while the lower segment of tether may have to be pretty beefy to have the appropriate tensile strength. If the tubing used to pressurize the kites can be incorporated into the tether, that would simplify things a bit more.
     
  7. Nov 11, 2006 #6

    Danger

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    Okay... I'm pissed as a nit right now... leftover from the Legion Remembrance Day party. I still don't see how you would vary the thickness of the tether during its course.
     
  8. Nov 11, 2006 #7

    turbo

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    Not actively, a simple taper.
     
  9. Nov 12, 2006 #8

    Danger

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    Okay... I must have missed something in the original explanation. I was under the impression that the 'tether' is solidly attached to the airfoils and revolves around the system with them.
     
  10. Nov 12, 2006 #9

    turbo

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    The kites do not revolve or loop or anything like that. They are intended to climb and dive alternately in unison, pulling out a length of tether, then diving so it can retract. This pumping action is translated into a rotational motion at the base because the tether is wrapped around a drum of some sort, which will spin counterclockwise then clockwise alternately as the tether is pulled out and retracted.
     
  11. Nov 12, 2006 #10

    Danger

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    Thanks, Turbo. That clears it up. I thought that it was set up something like an aerial gondola, with the kites dropping down one side and climbing up the other in a constant motion. Makes sense now.
     
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