ORIGINAL: rainedave
Here are Jim Feldmann's words:
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I know it is confusing, but look at the RCM Sportster's airfoil and then look at the Super Sportster's airfoil. The former is flat-bottomed, the latter is fully symmetrical. Being performance oriented, I always look at such details. Perhaps the authors meant "in spirit" and not in the particulars? Hard to argue with the article. Thanks for bringing it to our attention.
Ed Cregger