Everything Old is new again - Flettner Rotor Ship is launched

Discussion in 'Boat Design' started by rwatson, Sep 1, 2008.

  1. Burkhard
    Joined: Nov 2020
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    Burkhard Junior Member

    Health is our greatest asset. I am happy to hear that your wife survived this illness well.
    I am currently building a low cost Flettner rotor for my mini boats. Maybe it is an inspiration for you to build with similar means, although I know that other dimensions are needed for your boat.
     
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  2. Yobarnacle
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    Yobarnacle Senior Member holding true course

    I would like very much to see what you come up with
     
  3. Burkhard
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    Burkhard Junior Member

    Here my vid: DIY Flettner Rotor part1
     
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  4. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Very impressed with all four of your videos. What maximum speeds were you achieving on the sled run?
    I never considered making the rotor out of such apparently flimsy materials. Why did you abandon the Styrofoam in favor of much heavier particle board? Why did you abandon the drill motor? I sense you had good reasons, not doubting your judgement, just curious what you observed to convince you the changes were necessary.

    Final question. When do we get to see the practical Flettner rotor test on your folding kayak?

    Superb videos and ideas.
     
  5. Burkhard
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    Burkhard Junior Member

    First of all for tobogganing. My top speed so far was around 100 kph. You can find more sledding videos of me on my yt channel ˋ 57buni ´.
    The new disc consists of ˋStyrodur´. The material is also a rigid foam, but stronger and heavier than styrofoam. The styrofoam was too soft. With each assembly and disassembly, small parts came loose and thus widened the cutout. The entire rotor (without drive) now weighs approx. 3 KG. And I still find that very easy.
    In the case of the drive, the cordless drill Unit began to vibrate at speeds below 500 rpm due to the long rotor. Despite a few modifications, I did not get rid of this vibration, so I had to build a more stable drive unit. This unit weighs 5.3 KG with battery.
    The video with the practical test is expected to be ready this week. Unfortunately, it will not be a water test but a land test. The water test will then take place next summer.
     
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  6. Yobarnacle
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    Yobarnacle Senior Member holding true course

    thanks
     
  7. Burkhard
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    Burkhard Junior Member

    Here the Video: DIY Flettner Rotor Part 3
     
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  8. Yobarnacle
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    Yobarnacle Senior Member holding true course

    thanks
    You are an inspiration!
     
  9. Burkhard
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    Burkhard Junior Member

  10. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    Das hat Spaß gemacht zu sehen!
    That was fun to watch!
     
  11. Howlandwoodworks
    Joined: Sep 2018
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    Location: MO

    Howlandwoodworks Member

    Here is an old Popular Science from Jan 1984.
    The first Flettener-rotor windship built by Anton Flettener in 1920s.
    The article says that the Magnus effect was discovered by Gustav Magnums in 1852. Anton Flettener attempt to drive a ship with the Magmus effect in 1920s. He mounted two cylinders on a schooner and sail across the Atlantic in 1926, and since have been called the Flettener's Rotor ship. Oil was a dime a barrel and was replacing coal. At that time Flettener turned to designing airplanes for Hitler.
    The 42' 17 ton Tracker in the photo below under rotor power alone, reached a max speed of 6.1 knots in an 18.4 wind and a true wind angle of 122 degrees. Huh
    Article by : (C. P. Gilmore)

    upload_2020-12-2_15-37-13.png
     
    Last edited: Dec 3, 2020
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  12. rwatson
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    rwatson Senior Member

  13. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    I assume motor polarity can be reversed to compensate for change in wind direction?
     
  14. Yobarnacle
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    Yobarnacle Senior Member holding true course

    you assume correctly, the cylinder spins the opposite direction to tack
     

  15. Burkhard
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    Burkhard Junior Member

    hoytedow, in part2 of my video remote control is briefly explained (in German, sorry). The direction of rotation is changed with a 2-pole changeover switch. The speed is continuously regulated via a potentiometer. Rotor speed is 0 - 1000 rpm. Since the rotor speed should be about three times the wind speed in order to get the best efficiency, I cover winds up to 5 Bft with this speed range. That's enough for my little boat. I have handwritten a scale from 1 to 6 on my remote control. 1 corresponds to a wind speed of 1 m / s (rotor speed: 150 rpm) and so on.
    Unfortunately I had changeable winds (0-4 m / s) and changing wind directions during my test. It was interesting to note that when the rotor speed was unsuitable (too high or too low) the propulsion decreased significantly.
     
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