Just try this, it's called "FX 63-137 13,7% smoothed" but I have no idea if it's really smooth. Rename .txt to .dat, it's the common dat format.

Addendum: Maybe it only looks wavy because there is no antialiasing in the programs you use to display the outline. The pixel steps might fool us. Here's how it looks converted to DXF and displayed with the SolidWorks viewer. And here's the coordinate table and pencil drawing from the wind tunnel department of Stuttgart University where FX Wortmann worked.