undercambered vs flat bottomed wing
Yesterday we were flying in 15 MPH winds. I was flying with a wing of 8% thickness and 3% mean camber (undercamber). Some of my flying buddies were flying planes with flat bottomed airfoils of 12% thickness and about 4% camber. All the planes had about the same wing loading of 8 ounces per square foot. My plane was able to penetrate noticable better than the others.
I maintain that you can't generalize on the basis of flat bottomed versus undercambered.