While searching for symmetric profiles I stumbled across different definitions (point-clouds) of the NACA 642-015A profile.

  1. http://airfoiltools.com/airfoil/seligdatfile?airfoil=n64015a-il
  2. http://www.airfoildb.com/airfoils/418.dat

The figure below (skewed) shows the difference in percent chord on the secondary axis (green markers).

enter image description here

What causes these differences and is there a analytical description I could use to create a point-cloud with higher resolution.

Another question is: The NACA Reports I could find via Google all feature the NACA 642-015 (without the "A"). The difference between NACA 642-015A and NACA 642-015 is an increased thickness of the A-version towards the trailing edge. Who introduced or developed the A-version?

  • $\begingroup$ Have you tried Theory Of Wing Sections by Abbott & Von Doenhoff? $\endgroup$
    – Koyovis
    Jul 31, 2017 at 12:30
  • $\begingroup$ sure, but I could not find the 64_2 015A in them, do you have a profile description in yours? $\endgroup$
    – rul30
    Jul 31, 2017 at 12:41
  • $\begingroup$ The "A" simply denotes that the last 20% of the contour are straight lines. This was made to simplify the construction of wing and flaps. $\endgroup$ Aug 7, 2017 at 11:11

1 Answer 1


This report seems to include a reference to an analytical description of 6-series airfoils

enter image description here

On your second question: found this reference in Synthesis Of Subsonic Airplane Design by E. Torenbeek:

A modification to the standard series is the A-series in which the sharp trailing edge angle is replaced by a larger one, resulting from straight contours which run from 80% chord backwards.

The paragraph contains a reference to "Theoretical and experimental data for a number of NACA 64-series airfoil sections" which turns out to be NACA LM R6J01

  • $\begingroup$ Thanks @Koyovis, this helped a lot, really!. BUT (I'll open a new question for this though, I am not able to use the equations to create the airfoils. I'll get there, thanks! $\endgroup$
    – rul30
    Jul 31, 2017 at 15:27
  • 1
    $\begingroup$ Actually I just realised that the equation you cited does not recreate the thickness-distribution but the chamber-line, which is a straight line for a symmetrical airfoil. $\endgroup$
    – rul30
    Aug 1, 2017 at 20:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.