Fin Drive and Stabilization

Discussion in 'Pod Drives' started by Boston, Jun 4, 2012.

  1. SudorracMechEng
    Joined: Mar 2012
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    Location: australia

    SudorracMechEng Junior Member

    I have finally made time available to start manufacturing the driving system - Fingers crossed "frosty" stays out of this thread, although it was quite amusing to watch Spork absolutely own him the whole thread haha!
     
  2. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    G'day

    I have built bigger !
    The hulls are off a windRider tri sailboat and still works good, haven't wrecked any of the sail setup !
    This is a manned vessel to which conduct experiments of the fin drive system.
    I have also setup up to take the small electric outboard so i can give a Watt for Watt comparison between the two drives, this will give the quantifiable proof needed for efficiencies !
    I intend to use a data logger (Watts) and GPS (Speed) to compare.
    The fin drive mounts up front exactly were the elec outboard is mounted
    Sitting below were i sit so i can observe what is happening and also adjust pitch & frequency on the fly and observe that behaviour also
    It has 2 fins and they can have a pitch or 60 deg with a freq of 120 deg, this is twice that of the 1/4 scale fin boat !
    there are a lot of little bugs occurring so i think bigger scale and get my face in there to observe !
    Im nearly ready for some trials and intend to publish results here good or bad !
    Regards
    Craig
    Swasshdrive
     

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    Last edited: Sep 4, 2012
  3. kjell
    Joined: Aug 2005
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    Location: mallorca

    kjell Senior Member

    Craig.
    Congratulation for your test boat. I was using the same idea when I was testing my WING-DRIVE.
    Kjell
     

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  4. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    Pretty cool Kjell
    Whats the solar panel for ?
    Maybe you could explain the whole rig....very interesting !
    regards
    Craig
     
  5. kjell
    Joined: Aug 2005
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    Location: mallorca

    kjell Senior Member

    Craig.
    The solar panels are to charge the 12 volt batery I use to run the electric outboard motor installed in the rudder. The WING-DRIVE is the modern way to use wind propulsion. The WING-DRIVE is an automatic finger tip controlled navigating system.
    Kjell
     

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  6. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    Any idea what the nominal efficiency is of the electric outboard ?, looks the same make i have (Minn kota)
    My 30 size mini kota unit draws 50 watts to run in air on 1st setting, must have some fierce internal resistance !
    Regards
    Craig
     
    Last edited: Sep 9, 2012
  7. kjell
    Joined: Aug 2005
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    Location: mallorca

    kjell Senior Member

    The Minn Kota Endura 30 produce max 30 pounds of thrust.
     
  8. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    I kind of know that, its written on the cover:rolleyes:
    Do you know what watts or KW are pulled from the batt when asked to produced 30 lds of thrust form this unit?
    Do you know what the efficiency of this unit is ?, or is it you just like to state the obvious !
    Craig
     
  9. kjell
    Joined: Aug 2005
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    Location: mallorca

    kjell Senior Member

    The best way to get this information is to prepare the floating test equipment with spring loaded balance weight, volt meter and amp. meter. Make I list of power consumption and thrust. Then compare the result from your Swashdrive.
     
  10. latestarter
    Joined: Jul 2010
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    Location: N.W. England

    latestarter Senior Member

    The attached advert says its maximum watts is 360 which suggests 30 amps max.

    http://www.grabner-sports.at/MINN-KOTA-electric-motors.1679.0.html?&L=2

    You are right about the internal resistance on these models which is wasteful. If you look at the 'Output performance' on the lowest setting you get 1.8 for 10 hours say 18 and on top setting 13.6 for 3 hours say 40.8 more than twice as much energy.

    Some Minn Kota motors have a Maximiser, an electronic device known as a chopper or PWM controller which switches the voltage on and off at high frequency rather than dissipating the extra energy through the resistors thus making it more efficient on lower settings.
     
  11. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    Thanks !
    360 watts is all i need, cheers !
     
  12. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    A bollard static thrust test is ok for the prop, the fin-drive as nearly zero static thrust. the thrust on the fin-drive is proportional to fin speed, it needs flow !
    I thought you would already know this Kjell ?
     
  13. kjell
    Joined: Aug 2005
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    kjell Senior Member

    Sorry but you are wrong in this question. The propeller and the tail are accelerating mas of water in the oposite direction of the thrust reading. This force will accelerate the boat to reach the speed the hull resistance permit.
     
  14. swashdrive
    Joined: May 2012
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    Location: SEQ, Aus.

    swashdrive Junior Member

    Sorry old mate but my pond & sea trials would suggest otherwise, i'm not sure your on the same page as i ! There a different dynamics at play that can only be realised and understood from a practical sense.
    I will not be doing your tugboat test !
     

  15. kjell
    Joined: Aug 2005
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    Location: mallorca

    kjell Senior Member

    The best is to make the tests is in a test tank with all the test instruments. This is very expensiv. Making speed/power tests without knowing the thrust your Swashdrive is producing, is waste of time.
     

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