"Neil Allison" wrote in message
...
I noticed this today: http://www.newscientist.com/article.ns?id=dn7867

"In wind tunnel tests, Salmon stuck sections of plastic piezo-electric
film to wing segments. This film vibrates when an electrical signal is
applied, producing sound.

Tests using a barely audible sinusoidal tone of about 400 hertz showed
22% increase in lift, compared with a standard wing"

I've not found the entire paper but wonder: what thoughts or experience
does anyone have on this topic as it might relate to gliding?

Apart from the obvious about giving your aircraft a "tune up"

Cheers,
Neil
--
Christchurch, NZ

This falls into the category of "active boundary layer control". It's a
fascinating area of aerodynamics that started with Gus Raspet's suction
scheme 50 years ago. Dr. Sinha's "deturbulator" films and this vibrating
plastic film are attempts to make it more practical. All of these have
produced impressive results in controlled experiments but developing them to
the point of practicality so they can survive in the field has been the
problem.

If it ever gets to the point that one of these schemes can be applied to an
older glider for a 25% increase in performance, I'd expect to see a lot of
people doing it.

Bill Daniels