Sailors wrong for thousands of years?

Discussion in 'Sailboats' started by backyardbil, Feb 7, 2011.

  1. wardd
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    wardd Senior Member

    no reason the mast couldn't be the shaft
  2. Windmaster
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    Windmaster Senior Member

    Vertical Axis - Nice idea, but doesn't do the job.

    From time to time, the vertical axis idea gets mentioned. The main attraction, being of course, that you don't need to orient it to the wind.
    However, there is no case where a boat, or indeed a land vehicle has ever been able to travel directly to windward with one, and without this ability, the main attraction and indeed advantage of a rotary sailing power is lost.
    It's not difficult to see why a vertical axis setup does not work directly to windward when you consider that the blade on a horizontal axis machine may achieve a lift to drag ratio of as much as 50 to 1 (50 times the lift for one of drag). This makes for super efficiency in that the rotating force (which we use to power the boat) could be 50 times greater than the drag which is tending to hold the boat back. By contrast, the drag of a vertical axis arrangement is considerable. True, they have been used successfully on land-based power generation turbines, but on a fixed base system the drag is of no importance since it does not matter how much you push the ground - it's not going to have any negative effect!
    Last edited: May 1, 2011
  3. Dave Gudeman
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    Dave Gudeman Senior Member

    Has anyone ever tried? I'd be interested to know more about any such attempts.

    I don't follow this. The force that would be applied to the wheels to make the land vehicle move forward would be determined by the gearing; not directly by the lifting force on the blades. Unless the drag is so much that it is causing the wheels to lose traction, the only effect is that you require a slightly lower gearing which would cause the vehicle to move a bit slower.

    The case is different on a boat, of course.
  4. Windmaster
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    Windmaster Senior Member

    The only attempt I have seen is one of the entries in the landcart "wind energy events" which have been taking place in Holland and Denmark in the last few years I have seen some video footage of one of the entrants with a vertical axis turbine. The shot shows a team of people pulling a rope to get the rotor up to speed before (presumably) setting it on its way directly to windward, but there is no view of it actually proceeding in the required direction. That's the only time I have seen any evidence of an attempt, and since I am sceptical that it would work, I don't want to spend a lot of time and energy on it myself. But anyone else is welcome to try!

    On the point about the gearing, yes, that is true that you could gain mechanical advantage by gearing down. However, you are still facing a pulling match between the drag holding you back and the rotating force which you want to use to push you forward. You would have to gear down a whole lot, which would (IMHO) result in creeping forward minimally in a very impractical way. In the case of a boat, it is not so very different actually.
  5. Jack Hickson
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    Jack Hickson New Member

    Tried vertical axis on a wind generator once . Useless. The non driving one was strictly drag. With a blade, both provide power full time.
  6. hawkerdonkey
    Joined: Apr 2008
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    hawkerdonkey Junior Member

    Azipod thruster

    Hello to all,

    I've very much enjoyed reading the banter on this particular subject and my $0.05 would go to this beauty:

    One Rebuit Retractable horizontal drop down
    Type Wartsila Lips CS1500-250 MNR
    Power Rated 1550 KW
    Motor Speed 1000 rpm
    Prop. dia. 2300 mm
    Stem Length
    Drive Horizontal
    Motor voltage 690
    Status Rebuilt
    Class Lloyds
    Mounting Under water mountable
    Available now
    Warranty none
    Includes motor and control gear, couplings
    Installation drawing available
    Lloyds cert available

    from this guy

    He has a lot of other heavy metal too. Connected to a slow turning, correctly calculated windmill (blade-Tip ratio et al) and plant it at the back of something like this for fuel conservation purposes

    All within budget and delivered before the deadline :D

    While we're at it, I still haven't found a marine application to these yet (jet?) but at the tip of the blades, on a calm day should cause a bit of a stir I recon.


  7. nate teach
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    nate teach How hard can it be? :/

    so what happens when the wind is coming from behind you?

  8. hawkerdonkey
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    hawkerdonkey Junior Member

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