Quote:
Originally Posted by Otto
Feathers, fur on otters and seals, etc. also act as compliant wall surfaces, helping to dampen the oscillation of turbulent flow at its source, thereby reducing drag. This per research by Denis Bushnell et al at NASA Langley in the 1980s, with whom I spoke briefly at the time.
Also, some homebuilt airplane guy in Alaska about that time tried an experiment where he says he put fur (coulda been polar bear fur, but I don't recall exactly) on his plane, and reported that it reduced the drag, presumably for the same reasons. He approached the Air Force with this idea, and they told him to take a hike. This per Sport Aviation article at the time.
Perhaps this phenomenon stems from the same concept as the Sinha deturbulator tape, which is claimed to counteract turbulent flow as it begins.
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I have never heard of this fellow, but what the site advocates is the same material that the US navy already deployed. As per my earlier post the technology was lifted off of Mako sharks(tests were prompted because the shark was able to achieve astounding power-weight ratio with normal drag).
That technology works by trapping a layer of fluid against the surface "permanently." It doesn't flow at all. The barrier allows for a semi-compressable membrane that can assume the most hydro-aerodynamic shape possible within the micro-meter thickness. The drag between the fluid air and the trapped air creates a lower drag. It would be like engineering panels on a car that could manipulate slightly to take advantage of instantaneous low or high pressure zones and then return to normal as they dissipate. Infinitely more efficient than actually using a mechanical system because the sensors would disrupt flow and the equipment would be bulky and too slow.