Kinda off the subject, but if you are looking for more efficiency, check out the cross section of a dragonfly wing - looks nothing like a conventional airfoil - but was tested to give high lift for a given glide path( I thnk I remember 15% better by one study) try this http://jeb.biologists.org/cgi/content/full/207/24/4299 or http://search.yahoo.com/search?fr=sb...ics&btn=Search Granted they're wings also employ sculling and independant movement, but we must remember, insects have been flying, and therefore refined by nature, for far longer than any other class of animal(bees and flys don't count, they fly differently - like a hummingbird at hover). Also keep in mind, that bird wings(the ones man has roughly copied) were originally used not to fly, but to increase ground traction for running.