DSS 49er

Discussion in 'Sailboats' started by revintage, Jan 12, 2019.

  1. TANSL
    Joined: Sep 2011
    Posts: 5,428
    Likes: 145, Points: 73, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    With the words "might", "rough", "estimate", you can not prove anything, and I can not refute anything. I, as a technician, am used to more precision.
     

  2. revintage
    Joined: Nov 2016
    Posts: 110
    Likes: 14, Points: 18, Legacy Rep: 10
    Location: Sweden

    revintage Senior Member

    Hey guys, sorry for my outburst against DL yesterday(removed it), but his negative and irrelevant sub discussions isn´t my cup of tea. He is now on my "Ignore" list.

    TANSL, from your answers to DL I understand that his guesses of foil weight for some reason came up. What Quant 23´s foils weigh is totally irrelevant here, as DL must have been aware of.

    I have stated what my foils, including fittings, will weigh, after careful but simple calculations in Excel. I have also calculated, that 10kg extra weight adds 0.2 knots to lift off speed, which means foil weight is no big deal, even if they should land on 15kg each.

    The straight foil sections I build for my trifoiler around Windknife´s Foil Nose 2.FOIL NOSE - www.windknife.com http://www.windknife.com/full-foil/foil-nose, are 2 kg/m with 160 mm chord and I intend is to use them in this project too, but with above 200 mm chord. They have been simulated in XFoil with help from Doug Halsey and in JavaFoil by me. My N12FLAT foil section is adequate (but not optimal). See below.

    As Ozfred pointed out, lifting the windward foil forward might be a problem. If it doesn´t work, my second option is to use a hinge like the Vampire Project(below). Somewhat more elaborate but doable as the gunwale is extremely rigid on the 49er. It can, if needed, be strengthened with a strut to the mast step region. Will not be a big problem as I have a well equipped workshop.

    N12FLAT.png n12flatpr.png hinge.png
     
    Last edited: Jan 30, 2019
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