Recent Content by mm7

  1. mm7
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    Foil design for windsurfing

    Hi Skyak, thanks for your ideas, realy helpful! regarding to test H105 with a flap, I do not know how to make flaps in XFLR5. I could try to make...
    Post by: mm7, Sep 3, 2017 in forum: Hydrodynamics and Aerodynamics
  2. mm7
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    Open Source software list

    Hi, there are free software. One of them is FreeShip+ 4Lazarus Open source, binaries for Linux 64bit and for Windows. You can download it...
    Post by: mm7, Oct 14, 2016 in forum: Software
  3. mm7
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    Flat or round bottom for a foiler "board"

    Thanks, I am doing the reading. Reading: Fritsh,Bertram, "Hydrodynamic Design Aspects for Fast Conventional Vessels" Savitsky, D.,...
    Post by: mm7, Jan 27, 2014 in forum: Sailboats
  4. mm7
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    Flat or round bottom for a foiler "board"

    Two flows still meet on leading edge. Not same particles though. :) But it is not relevant here. Still the trimmed bottom deflects water down....
    Post by: mm7, Jan 25, 2014 in forum: Sailboats
  5. mm7
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    Flat or round bottom for a foiler "board"

    I do not disagree with that. But there an airfoil section is illustrated. It has an aerodynamic profile and thickness. This thickness makes upper...
    Post by: mm7, Jan 25, 2014 in forum: Sailboats
  6. mm7
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    Flat or round bottom for a foiler "board"

    Yes of course Xflr5. Sorry for misleading. I thought it uses some generic formula. I just divided Cl half. Because I assumed that for a flat...
    Post by: mm7, Jan 24, 2014 in forum: Sailboats
  7. mm7
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    Flat or round bottom for a foiler "board"

    I calculated based on: - foil: span 1m, chord 10sm, Area 1000sm2 - hull bottom: length 3m, beam 0.4m, plan area: 6000sm2 Yes, it is not...
    Post by: mm7, Jan 24, 2014 in forum: Sailboats
  8. mm7
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    Flat or round bottom for a foiler "board"

    I've calculated lift in XFoil for a long thin flattish symmetric foil chord 3m, beam 0.4m. on speed 2m/s. Yes its Cl is 20 times less than Cl of...
    Post by: mm7, Jan 24, 2014 in forum: Sailboats
  9. mm7
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    Flat or round bottom for a foiler "board"

    I totally agree, and I was not going to make a wide one from very beginning. My question was - round vs flat bottom. It is just bottom, the long...
    Post by: mm7, Jan 23, 2014 in forum: Sailboats
  10. mm7
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    Flat or round bottom for a foiler "board"

    I am reading interesting thread on same topic here http://www.moth.asn.au/forum/3-hull-shape/2920-rounded-hull-vs-chine
    Post by: mm7, Jan 23, 2014 in forum: Sailboats
  11. mm7
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    Flat or round bottom for a foiler "board"

    Doug, another simple example. Will a rectangle cross-section that has depth 2m and beam 0.5m have less resistance than cross-section 1x1m? Both...
    Post by: mm7, Jan 22, 2014 in forum: Sailboats
  12. mm7
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    Flat or round bottom for a foiler "board"

    My question was not about stability. It was purely abstract question regarding resistance ant its relation to waterline L/B only. Imagine we add...
    Post by: mm7, Jan 22, 2014 in forum: Sailboats
  13. mm7
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    Flat or round bottom for a foiler "board"

    Thanks all! I see that the most practical approach will be to get the proven Moth type shape. The question is answered.
    Post by: mm7, Jan 21, 2014 in forum: Sailboats
  14. mm7
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    Flat or round bottom for a foiler "board"

    Thanks Doug, your explanation looks very convinceable. The only moment. I do not rely on planing of flat (and narrow) bottom. At least not on the...
    Post by: mm7, Jan 21, 2014 in forum: Sailboats
  15. mm7
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    Flat or round bottom for a foiler "board"

    I've analyzed resistance of hulls in FreeShip! Plus. WS board is 1.5-2 times (depending on analysis method) more resistive on speeds 1 to 5 knots,...
    Post by: mm7, Jan 21, 2014 in forum: Sailboats