I know the title is 'corny' but after cruising through those hundreds of sections graciously provided by "krauss", I couldn't help wondering why the 18.3% thick Gottingen 679 showed such a superior L/D ratio (64.8) when that number is usually reserved for thinner airfoils. The plotted polars add up (divide that is) and I know the Rn is low at 100000. Could any of the owners of aerodynamics programs please run the numbers for me at R=500000, 1million and 1.5million? The last mentioned number approximates the landing approach speed for typical ultralights. Are there any stall problems with that section in your opinions? Thanks.