It seems as humans that too many of us have been guilty of accepting established theory.
Some fascinating newer looks at Ludwig Prandtl's later and until recently ignored equasions are forcing a major re-think for wing design for efficiency.
An American Albion Bowers has dredged up this little known later equasion of Prandtl's and has been figuring out how to use it.
Quick summary:
A bird's wings have their angle of incidence vary throughout their length, typically there is no winglet as per aircraft.
It seems that designer's use of winglets is only a small part of the story. In bird's wings, there is very substantially lower angle of incidence over a large portion of the outer wing, providing a function similiar to the winglet over a much wider span.
Instead of wingTIP vorticies, the vorticies are approx 3/4 of the way from centre to wing tip and coincide with the specific overlap birds use flying in formation. According to Albion Bowers, this makes for massive lift vs drag improvements.
Not having been through aeronautical design training I don't have much of a vested interest in claiming that the eliptical wings favoured by Prandtl's first famous equasion are the be-all-end-all and I'm really fascinated to see if this is something that we can (likely) utilise for improved hydrofoil lift to drag ratios.
http://www.nestofdragons.net/weird-airp ... l-project/
Don't you just love the hectic pace of innovation in new sports? Or in this case... Cribbing on thousands of milions of years of evolution