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Re: [ksurf] LE diameter size

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  • CCKiteboarder@hotpop.com
    Are you saying that you don t believe the claims that are being made for the advantages of a smaller LE Tube? Steve Carson City, NV, USA
    Message 1 of 6 , Jun 2, 2005
      Are you saying that you don't believe the claims that are being made for the advantages of a
      smaller LE Tube?

      Steve
      Carson City, NV, USA



      06/02/05 4:41:02 AM, Hung Vu <hungvu2000@...> wrote:

      >I played around with some airfoil analysis and by reducing the leading
      >edge diameter from 10% to 5% of chord, the maximum L/D ratio of the
      >airfoil increases from 115 to 126 (induced drag is not included) and the
      >maximum Lift Coefficient increases from 1.57 to 1.79.
      >
      >So it's around 10% to 15% increase in airfoil performance for both
      >maximum L/D and Lift by reducing the LE diameter in half.
      >
      >I also increased the LE diameter to 15% and the result was not very
      >desirable so you definitely don't want to go there.
      >
      >P.S., These numbers should be taken as an approximate.
      >
      >P.P.S, The airfoil moment (tendency to flip over the nose) is slightly
      >more stable with smaller LE diameter
      >
      >P.P.P.S., Most modern LE diameter on market is around 9 or 10% of chord.
      >
      >Hung.
      >
      >
      >[Non-text portions of this message have been removed]
      >
      >
      >
      >If you are new to kitesurfing, please visit
      >http://www.KitesurfingSchool.org/faqs.htm for the answers
      >to the most frequently asked questions.
      >
      >=== to unsubscribe, please send an email to kitesurf-unsubscribe@yahoogroups.com ===
      >Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >
    • Loco 4 Olas
      sounds like the opposite to me. ... From: To: Sent: Friday, June 03, 2005 4:23 AM Subject: Re: [ksurf] LE
      Message 2 of 6 , Jun 2, 2005
        sounds like the opposite to me.

        ----- Original Message -----
        From: <CCKiteboarder@...>
        To: <kitesurf@yahoogroups.com>
        Sent: Friday, June 03, 2005 4:23 AM
        Subject: Re: [ksurf] LE diameter size


        > Are you saying that you don't believe the claims that are being made for
        > the advantages of a
        > smaller LE Tube?
        >
        > Steve
        > Carson City, NV, USA
        >
        >
        >
        > 06/02/05 4:41:02 AM, Hung Vu <hungvu2000@...> wrote:
        >
        >>I played around with some airfoil analysis and by reducing the leading
        >>edge diameter from 10% to 5% of chord, the maximum L/D ratio of the
        >>airfoil increases from 115 to 126 (induced drag is not included) and the
        >>maximum Lift Coefficient increases from 1.57 to 1.79.
        >>
        >>So it's around 10% to 15% increase in airfoil performance for both
        >>maximum L/D and Lift by reducing the LE diameter in half.
        >>
        >>I also increased the LE diameter to 15% and the result was not very
        >>desirable so you definitely don't want to go there.
        >>
        >>P.S., These numbers should be taken as an approximate.
        >>
        >>P.P.S, The airfoil moment (tendency to flip over the nose) is slightly
        >>more stable with smaller LE diameter
        >>
        >>P.P.P.S., Most modern LE diameter on market is around 9 or 10% of chord.
        >>
        >>Hung.
        >>
        >>
        >>[Non-text portions of this message have been removed]
        >>
        >>
        >>
        >>If you are new to kitesurfing, please visit
        >>http://www.KitesurfingSchool.org/faqs.htm for the answers
        >>to the most frequently asked questions.
        >>
        >>=== to unsubscribe, please send an email to
        >>kitesurf-unsubscribe@yahoogroups.com ===
        >>Yahoo! Groups Links
        >>
        >>
        >>
        >>
        >>
        >>
        >>
        >
        >
        >
        >
        >
        > If you are new to kitesurfing, please visit
        > http://www.KitesurfingSchool.org/faqs.htm for the answers
        > to the most frequently asked questions.
        >
        > === to unsubscribe, please send an email to
        > kitesurf-unsubscribe@yahoogroups.com ===
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        >
        >
      • ex_cpe
        ... ..........I thought about this but didn t have/take the time to put the tape to two new, 05 Kites: Windwing Rapture 15M and Naish Torch 14M. I like both
        Message 3 of 6 , Jun 21, 2005
          --- In kitesurf@yahoogroups.com, Hung Vu <hungvu2000@r...> wrote:
          > I played around with some airfoil analysis and by reducing the leading
          > edge diameter from 10% to 5% of chord, the maximum L/D ratio of the
          > airfoil increases from 115 to 126 (induced drag is not included) and the
          > maximum Lift Coefficient increases from 1.57 to 1.79.
          >
          > So it's around 10% to 15% increase in airfoil performance for both
          > maximum L/D and Lift by reducing the LE diameter in half.
          >
          > I also increased the LE diameter to 15% and the result was not very
          > desirable so you definitely don't want to go there.
          >
          > P.S., These numbers should be taken as an approximate.
          >
          > P.P.S, The airfoil moment (tendency to flip over the nose) is slightly
          > more stable with smaller LE diameter
          >
          > P.P.P.S., Most modern LE diameter on market is around 9 or 10% of chord.
          >
          > Hung.
          >


          ..........I thought about this but didn't have/take the time to put the tape to two new, 05
          Kites: Windwing Rapture 15M and Naish Torch 14M. I like both kites - for different
          reasons, but they seem to come from different schools of thought. The Naish School of
          Evolution and Hansen's Vision Lab.

          The Rapture looks a lot like the new announcements from Cabby and Takoon except
          without: fussy cordage, baggage of royalties and a 'borrowed' design. I prefer people who
          stick their necks out and try something new - even if it's Best with their new Hellfish.

          Numbers: The Torch has a diameter of 10"/25.5cm and the Rapture has a diameter of
          13"/33cm....but to my surprise: both have a cord (L.E. to T.E. on the C/L) of 80"/203cm.
          My ADD has kicked in, so I'll leave you to the calculations...and don't flog me if I'm off a
          couple of cm's.

          So Hung: wazzit mean?

          Jim
        • ex_cpe
          ... who ... 203cm. ... ..........ERROR! Forget I said diameter - the circumference of the Torch is roughly 20 / 51cm and the Rapture is 26 /66cm.
          Message 4 of 6 , Jun 22, 2005
            --- In kitesurf@yahoogroups.com, "ex_cpe" <wetstuff@i...> wrote:
            > --- In kitesurf@yahoogroups.com, Hung Vu <hungvu2000@r...> wrote:
            > > I played around with some airfoil analysis and by reducing the leading
            > > edge diameter from 10% to 5% of chord, the maximum L/D ratio of the
            > > airfoil increases from 115 to 126 (induced drag is not included) and the
            > > maximum Lift Coefficient increases from 1.57 to 1.79.
            > >
            > > So it's around 10% to 15% increase in airfoil performance for both
            > > maximum L/D and Lift by reducing the LE diameter in half.
            > >
            > > I also increased the LE diameter to 15% and the result was not very
            > > desirable so you definitely don't want to go there.
            > >
            > > P.S., These numbers should be taken as an approximate.
            > >
            > > P.P.S, The airfoil moment (tendency to flip over the nose) is slightly
            > > more stable with smaller LE diameter
            > >
            > > P.P.P.S., Most modern LE diameter on market is around 9 or 10% of chord.
            > >
            > > Hung.
            > >
            >
            >
            > ..........I thought about this but didn't have/take the time to put the tape to two new, 05
            > Kites: Windwing Rapture 15M and Naish Torch 14M. I like both kites - for different
            > reasons, but they seem to come from different schools of thought. The Naish School of
            > Evolution and Hansen's Vision Lab.
            >
            > The Rapture looks a lot like the new announcements from Cabby and Takoon except
            > without: fussy cordage, baggage of royalties and a 'borrowed' design. I prefer people
            who
            > stick their necks out and try something new - even if it's Best with their new Hellfish.
            >
            > Numbers: The Torch has a diameter of 10"/25.5cm and the Rapture has a diameter of
            > 13"/33cm....but to my surprise: both have a cord (L.E. to T.E. on the C/L) of 80"/
            203cm.
            > My ADD has kicked in, so I'll leave you to the calculations...and don't flog me if I'm off a
            > couple of cm's.
            >
            > So Hung: wazzit mean?
            >
            > Jim



            ..........ERROR! Forget I said 'diameter' - the circumference of the Torch is roughly 20"/
            51cm and the Rapture is 26"/66cm. Dummm-sh_t.. My hands think better than my
            head.

            Jim
          • Hung Vu
            Jim, The newly corrected numbers would bring the Torch and Rapture LE size closer to the industry norm of around 9 to 10% of chord. P.S., My Patriot 9.8 LE
            Message 5 of 6 , Jul 3 3:11 PM
              Jim,

              The newly corrected numbers would bring the Torch and Rapture LE size
              closer to the industry norm of around 9 to 10% of chord.

              P.S., My Patriot 9.8 LE size is around 8.5% of chord.

              Hung.

              ex_cpe wrote:

              >--- In kitesurf@yahoogroups.com, "ex_cpe" <wetstuff@i...> wrote:
              >
              >
              >>--- In kitesurf@yahoogroups.com, Hung Vu <hungvu2000@r...> wrote:
              >>
              >>
              >>>I played around with some airfoil analysis and by reducing the leading
              >>>edge diameter from 10% to 5% of chord, the maximum L/D ratio of the
              >>>airfoil increases from 115 to 126 (induced drag is not included) and the
              >>>maximum Lift Coefficient increases from 1.57 to 1.79.
              >>>
              >>>So it's around 10% to 15% increase in airfoil performance for both
              >>>maximum L/D and Lift by reducing the LE diameter in half.
              >>>
              >>>I also increased the LE diameter to 15% and the result was not very
              >>>desirable so you definitely don't want to go there.
              >>>
              >>>P.S., These numbers should be taken as an approximate.
              >>>
              >>>P.P.S, The airfoil moment (tendency to flip over the nose) is slightly
              >>>more stable with smaller LE diameter
              >>>
              >>>P.P.P.S., Most modern LE diameter on market is around 9 or 10% of chord.
              >>>
              >>>Hung.
              >>>
              >>>
              >>>
              >>..........I thought about this but didn't have/take the time to put the tape to two new, 05
              >>Kites: Windwing Rapture 15M and Naish Torch 14M. I like both kites - for different
              >>reasons, but they seem to come from different schools of thought. The Naish School of
              >>Evolution and Hansen's Vision Lab.
              >>
              >>The Rapture looks a lot like the new announcements from Cabby and Takoon except
              >>without: fussy cordage, baggage of royalties and a 'borrowed' design. I prefer people
              >>
              >>
              >who
              >
              >
              >>stick their necks out and try something new - even if it's Best with their new Hellfish.
              >>
              >>Numbers: The Torch has a diameter of 10"/25.5cm and the Rapture has a diameter of
              >>13"/33cm....but to my surprise: both have a cord (L.E. to T.E. on the C/L) of 80"/
              >>
              >>
              >203cm.
              >
              >
              >>My ADD has kicked in, so I'll leave you to the calculations...and don't flog me if I'm off a
              >>couple of cm's.
              >>
              >>So Hung: wazzit mean?
              >>
              >>Jim
              >>
              >>
              >
              >
              >
              >..........ERROR! Forget I said 'diameter' - the circumference of the Torch is roughly 20"/
              >51cm and the Rapture is 26"/66cm. Dummm-sh_t.. My hands think better than my
              >head.
              >
              >Jim
              >
              >
              >
              >
              >If you are new to kitesurfing, please visit
              >http://www.KitesurfingSchool.org/faqs.htm for the answers
              >to the most frequently asked questions.
              >
              >=== to unsubscribe, please send an email to kitesurf-unsubscribe@yahoogroups.com ===
              >Yahoo! Groups Links
              >
              >
              >
              >
              >
              >
              >
              >
              >


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