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  1. #1
    saltwater_gypsy's Avatar
    saltwater_gypsy is offline Registered User
    Location : Now back in Scotland . Boat for sale
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    Default Downwind faster than the wind? Demonstration !!

    This a follow up to an recent post about wind propellor driven props.
    This clip is from an interesting boat design forum. Its not a boat but the autogyro principle is the same.
    Look here: http://www.youtube.com/watch?v=aJpdWHFqHm0
    "Cruising is boat maintenance in paradise"
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  2. #2
    Join Date
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    Default Re: Downwind faster than the wind? Demonstration !!

    I had some trouble believing what I was seeing, but it seems to rely on very low rolling resistance to make it work, so I don't expect to see it on a cruising yacht just yet, unless someone is going to produce a wind-driven hovercraft.
    Far away is near at hand in images of elsewhere

  3. #3
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    Default Re: Downwind faster than the wind? Demonstration !!

    I had trouble understanding what I was seeing. This video seems clearer:

    http://www.youtube.com/watch?v=1BRvYZd81AQ&NR=1

  4. #4
    nimbusgb is offline Registered User
    Location : A long way from my boat! :(
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    Default Re: Downwind faster than the wind? Demonstration !!

    In the second video the vehicle is actually in still air. The road is moving backwards not the air above it. There is a major energy input from the treadmill the only thing the propeller has to overcome is the rolling resistance and generation inefficiencies; the vehicle is not moving upwind at all. It looks cool but the science is quiet simple and very much traditional Newtonian! These guys have not invented a perpetual motion machine.
    "Tomorrow to fresh woods and pastures new"

  5. #5
    Join Date
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    Default Re: Downwind faster than the wind? Demonstration !!

    From what I could make out of the first video it was actually going upwind or had the wind on the port beam once it got going.

    Interesting point is that it was on a public road. I wonder what plod and elfin safety would say about that here?
    Working on immortality - One day at a time.

  6. #6
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    Default Re: Downwind faster than the wind? Demonstration !!

    [ QUOTE ]

    Interesting point is that it was on a public road. I wonder what plod and elfin safety would say about that here?

    [/ QUOTE ]

    You dont wonder - you already know, and it would undoubtedly be said in a patronising way.

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