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AF# lug sail darts

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  • tsgosnell
    Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them.
    Message 1 of 6 , Feb 3, 2011
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      Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them. My polysail for my Mayfly doesnt have them, and sets very well. Any help?
      Thanks
      Scott
    • Rob Kellock
      I think sail darts for camber do make a huge difference. I remember as a kid making a drinking straw glider with cambered cardboard wings, launching it from a
      Message 2 of 6 , Feb 3, 2011
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        I think sail darts for camber do make a huge difference. I remember as a kid making a drinking straw glider with cambered cardboard wings, launching it from a shed roof and being amazed at it's shallow glide angle, compared to normal balsa wood planes with flat wings, before it crash landed and destroyed itself!

        Seriously though, Nels has just posted a file where I describe using darts on a polytarp lug sail.

        http://groups.yahoo.com/group/Michalak/files/Balanced%20Lug%20Notes%20and%20Ideas/Lug%20Rig%282%29.pdf

        Cheers,

        Rob.

        --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@...> wrote:
        >
        > Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them. My polysail for my Mayfly doesnt have them, and sets very well. Any help?
        > Thanks
        > Scott
        >
      • sirdarnell
        Don t know where they go. However, like an airplane wing you want air moving faster over one side than the other. The higher speed (curvier in planes) side
        Message 3 of 6 , Feb 4, 2011
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          Don't know where they go.

          However, like an airplane wing you want air moving faster over one side than the other. The higher speed (curvier in planes) side has lower air pressure and thus the wing lifts into the this low pressure area. Airplanes wings have more curve on the top and thus we get the term lift.

          David

          --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@...> wrote:
          >
          > Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them. My polysail for my Mayfly doesnt have them, and sets very well. Any help?
          > Thanks
          > Scott
          >
        • tsgosnell
          Thanks for the file, I can figure it out now Scott
          Message 4 of 6 , Feb 4, 2011
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            Thanks for the file, I can figure it out now
            Scott

            --- In Michalak@yahoogroups.com, "Rob Kellock" <creditscorenz@...> wrote:
            >
            >
            >
            > I think sail darts for camber do make a huge difference. I remember as a kid making a drinking straw glider with cambered cardboard wings, launching it from a shed roof and being amazed at it's shallow glide angle, compared to normal balsa wood planes with flat wings, before it crash landed and destroyed itself!
            >
            > Seriously though, Nels has just posted a file where I describe using darts on a polytarp lug sail.
            >
            > http://groups.yahoo.com/group/Michalak/files/Balanced%20Lug%20Notes%20and%20Ideas/Lug%20Rig%282%29.pdf
            >
            > Cheers,
            >
            > Rob.
            >
            > --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@> wrote:
            > >
            > > Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them. My polysail for my Mayfly doesnt have them, and sets very well. Any help?
            > > Thanks
            > > Scott
            > >
            >
          • prairiedog2332
            Couple of things to add. In item #1 it stated the bottom dart is to be 4-5 times wider than the upper dart. I might go with 3-4 times. For example in Jim s
            Message 5 of 6 , Feb 4, 2011
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              Couple of things to add.

              In item #1 it stated the bottom dart is to be 4-5 times wider than the
              upper dart. I might go with 3-4 times. For example in Jim's instructions
              in his build book, for a 74 sq. ft. sail the top dart is 2.2" and the
              bottom one 6". BUT I do not want to contradict Rod because he tried it
              that way and it works for him whereas I haven't yet. I think it also
              depends on the weight of the polytarp. Lighter tarp will tend to stretch
              a bit after awhile so the sail will gradually get fuller and heavy tarp
              will stretch less. Mind you the battens may support lighter material to
              some extent.

              Overall his instructions are really worthwhile since you can make that
              sail in a day and you don't need a sewing machine. Not sure what Bear
              tape is but get the best reinforced "duct-type" tape you can afford I'm
              thinking. And "burnish" it down into the polytarp surface - as in rub it
              down really good with a rounded tool like the end of a screwdriver
              handle.

              I am a great supporter of a fully battened balance lugsail when using
              polytarp as you need no reef cringles sewn in - which do not marry well
              with polytarp in my opinion. What Rob has is a sort of hybrid balance
              lug/Chinese lug without all the complications of the sheetlet system.

              I have a few other ideas in that regard.

              Nels


              --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@...> wrote:
              >
              > Thanks for the file, I can figure it out now
              > Scott
              >
              > --- In Michalak@yahoogroups.com, "Rob Kellock" creditscorenz@ wrote:
              > >
              > >
              > >
              > > I think sail darts for camber do make a huge difference. I remember
              as a kid making a drinking straw glider with cambered cardboard wings,
              launching it from a shed roof and being amazed at it's shallow glide
              angle, compared to normal balsa wood planes with flat wings, before it
              crash landed and destroyed itself!
              > >
              > > Seriously though, Nels has just posted a file where I describe using
              darts on a polytarp lug sail.
              > >
              > >
              http://groups.yahoo.com/group/Michalak/files/Balanced%20Lug%20Notes%20an\
              d%20Ideas/Lug%20Rig%282%29.pdf
              > >
              > > Cheers,
              > >
              > > Rob.
              > >
              > > --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@> wrote:
              > > >
              > > > Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft
              sail, I have the plans, but not sure where to put the darts, or really
              if I even need them. My polysail for my Mayfly doesnt have them, and
              sets very well. Any help?
              > > > Thanks
              > > > Scott
              > > >
              > >
              >
            • graeme
              Some sail shaping dart math and graphs are here: http://marina.fortunecity.com/breakwater/274/2002/0615/index.htm#Sail%20Shaping
              Message 6 of 6 , Feb 4, 2011
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                Some sail shaping dart math and graphs are here:

                http://marina.fortunecity.com/breakwater/274/2002/0615/index.htm#Sail%20Shaping

                http://marina.fortunecity.com/breakwater/274/2002/0701/index.htm#Sail%20Shaping%202

                [The index table at http://www.buildboats.com/bbmichalakindex.html has a dud link for the second article above, but the link by date is ok.]

                Those articles build on earlier ones like:

                http://marina.fortunecity.com/breakwater/274/1999/0715/Index.htm#Polytarp%20Sharpie%20Sprit%20Sail

                http://marina.fortunecity.com/breakwater/274/1999/0801/index.htm#Polytarp%20Sharpie%20Sprit%20Sail%20#2

                http://marina.fortunecity.com/breakwater/274/1999/0815/Index.htm#More%20Polytarp%20Sails

                Graeme

                --- In Michalak@yahoogroups.com, "tsgosnell" <tsgosnell@...> wrote:
                >
                > Anyone have the specs for the AF3 lug sail darts? Its the 91 sqft sail, I have the plans, but not sure where to put the darts, or really if I even need them. My polysail for my Mayfly doesnt have them, and sets very well. Any help?
                > Thanks
                > Scott
                >
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