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Aerospace Airfoil leading edge radius

  1. Jun 17, 2011 #1
    Does anyone know how to determine the leading-edge radius of an airfoil using just the x y coordinates.
  2. jcsd
  3. Jun 17, 2011 #2


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    You could just do a curve fit and then find it analytically...
  4. Jun 18, 2011 #3
    I know you can do it in XFoil...

    1) Start XFoil
    2) type "NACA 0012"
    3) type "OPER"
    4) hit "enter/return" key
    5) type "GDES"
    6) a window pops up:
  5. Jun 18, 2011 #4
    Do you know if there is a way to output the value of rLE from XFOIL. I need the value of the leading edge radius for a code I am writing and would prefer to not have to enter that value manually..
  6. Jun 18, 2011 #5
    I knew I'd find it eventually... had to find my book first.

    Essentially, if you have a NACA 4 series then NACA ABCD, where CD gives the max thickness, t.

    Then: [itex]R_{LE}=1.1019t^{2}[/itex]
  7. Jun 18, 2011 #6
    And if all you have is x-y coordinates then you should be able to find 't' by the thickness distribution (assuming you know it's a NACA 4-series)

    [itex]\pm y_{t}=\frac{t}{0.20}\left(0.29690 \sqrt{x}-0.12600x-0.35160x^{2}+0.28430x^{3}-0.10150x^{4}\right)[/itex]

    The source: Theory of wing sections: including a summary of airfoil data By Ira H. Abbott, Albert Edward Von Doenhoff
    Last edited: Jun 18, 2011
  8. Oct 15, 2012 #7
    Hey! had more or less the same problem, do you think the equation given by Abbott gives an appropriate value if it's not a NACA four digit profile ? For example for normal nowadays aircrafts ? (I don't know what kind of profile I have)
    Last edited: Oct 15, 2012
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