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LE diameter size

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  • Hung Vu
    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
    Message 1 of 6 , Jun 2, 2005
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      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]
    • 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 2 of 6 , Jun 2, 2005
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        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 3 of 6 , Jun 2, 2005
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          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 4 of 6 , Jun 21, 2005
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            --- 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 5 of 6 , Jun 22, 2005
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              --- 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 6 of 6 , Jul 3, 2005
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                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
                >
                >
                >
                >
                >
                >
                >
                >
                >


                [Non-text portions of this message have been removed]
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