a airfoil problem

Hi, guys:
I got a problem about airfoil which puzzled me presently, for I am designing my midget, and for lack of wortmann laminar airfoil detailed data which I long forward, so I have to fall back on the naca 4412 temporarily, I found two naca reports, in which indicated that 4412 could reach 0.6 at angle of attack of 2 degree under the condition of Re=3 million and aspect ratio of 6, but in the another report which published by Russian show the naca 4412 CL at 2 degree angle of attack can only reach 0.45, which one is correct?? Below is the polar graphics, the first graphic is the Russian’s.

Originally Posted by johnnylee

Hi, guys:
I got a problem about airfoil which puzzled me presently, for I am designing my midget, and for lack of wortmann laminar airfoil detailed data which I long forward, so I have to fall back on the naca 4412 temporarily, I found two naca reports, in which indicated that 4412 could reach 0.6 at angle of attack of 2 degree under the condition of Re=3 million and aspect ratio of 6, but in the another report which published by Russian show the naca 4412 CL at 2 degree angle of attack can only reach 0.45, which one is correct?? Below is the polar graphics, the first graphic is the Russian’s.

and this polar cut from naca 824 report,