The team also discovered that two previously unknown forces occur at the end of each half-stroke. Like a tennis ball with backspin, the wing is pulled upward by lower pressure. The wing actually passes through a spinning vortex wake from the previous stroke. Dickinson says the wing can extract enough energy from this previous stroke to create significant upward lift. But these discoveries are just the tip of the iceberg, Dickinson says.
Many questions are still unanswered.
Michael Dickinson Copyright 2000 Jason Spingarn-Koff.