Originally Posted by ibillwilson
In my quest to understand things a little better, I found the following thread talking about the "NASA droop": http://www.rcgroups.com/forums/showthread.php?t=63140
The droop looks a lot like what I did when I added a strip to the bottom of the leading edge. Mine wasn't 40% of the wingspan, however, so I'm not sure how much of an effect it had vs curling up the trailing edge.
Richard Whitcomb designed the supercritical wing, which is flat on top and cambered on the bottom with a small cusp on the underside near the trailing edge. It almost looks like the beginnings of a small step. The purpose of the flat upper surface was to reduce the sonic boom.
He was also the inventor of the coke bottle fuselage.