[YavorD]

Originally Posted by Kwiatek

After making some more analyz there is definitly something wrong.

Polars Clmax/AoA which i used before from Profili or other sources were not reliable beacuse there were for RC models and for small Reynolds numbers.
...
Here are valuse which i read directly from charts ( for airfoils):

Plflaz - Clmax - 0,78, AoA - 16 deg
Fokker - Clmax - 0,67, AoA - 16 deg
Albatros -Clmax- 0,68, AoA - 14 deg
SpadXIII -Clmax- 0,52, AoA - 14 deg

They look somewhere very low but are quite possible.

Chart for Pflaz:

The above set of data was, probably, retrieved from the NACA reports. The scale factor is "twice dynamic pressure". In modern terms such values shall be multiplied by two. All the data come from a small scale test with a low Reynolds number.
Regards,
Yavor