Hello all,
Looking to understand the NACA numbering scheme used to define the Messerschmitt Bf 109K airfoil
NACA 2R1 14.2 NACA 2R1 11.35

How can these NACA numbers be plotted
The last 3 digits are % thick but the 2R1 is a mystery?

Thanks in advance,
Dave

I'm guessing that the 2R1 wasn't a mathematically calculated shape like the 4 and 5 digit series are. If I'm right it would just be an envelope shape that is altered for thickness. Other than that little gem I don't really know since I've never heard of the 2R1 airfoil.

Other than a general confirmation of the type of airfoil, with no explanation as to what's different about it, I found this on a Bulgarian site..
http://www.aeronautica-fm.de/Page103...09f_blatt1.gif
I'd use a 2414 myself.
..
Looked in Profili.... presuming the "R" is some "revised" designator for an NACA 2114, and plotted a 2414 on top... I got this.
Not enough difference to be concerned about for model size.

For your reference needs:
NACA 4 Series profiles - http://www.pagendarm.de/trapp/progra...les/NACA4.html
NACA 5 Series Profiles - http://www.pagendarm.de/trapp/progra...les/NACA5.html
NACA Airfoils for Windows - http://www.ctaz.com/~kelcomp/airfoils5.htm
Profili Program - http://www.profili2.com/eng/default_plans.htm

DOH! I should never post anything airfoil related without checking my copy of Profili 2 first. There's a 12% thick 2R1 12 in there. It's a fairly normal looking airfoil that has a small up curve in the lower trailing edge indicating some reflex to the camber line. Being quite normal looking I'd say it would work quite well up to a moderate wing loading. And the reflex would reduce any pitch stability issues related to the rather small stabilizer.

If true scale isn't an issue the Selig 8036 would be a good choice given it's proven ability to handle higher wing loadings with grace.

Thank you everyone,
I managed to scale the 2R1 X&Y numbers from profili & generated the correct %THK.

Kind regards,
Dave