Why don't wings have dimples 2

"Jim Logajan" wrote in message
.. .
Dancing Fingers wrote:
The thing of it is that the car they used, as I remember, also had a
very aerodynamic shape and it still helped.

Disagree - it was not "aerodynamic" on the downstream side.

Do you recall when they showed the wind tunnel and water tank tests?
Do you
recall seeing that there was an area behind the car with turbulent
air?
Well if the car had been elongated so that the body tapered off such
that
it filled that area of turbulence, then I suspect they would have
gotten
different results.

Check out the following site:

http://www.grc.nasa.gov/WWW/K-12/rocket/shaped.html

Notice that the prism has a slightly lower drag coefficient than the
flat
plate. As that web site states "Comparing the flat plate and the
prism, and
the sphere and the bullet, we see that the downstream shape can be
modified
to reduce drag."

I wonder if they would have gotten the same results by attaching a foil
to direct some of the air down from the trunk to make the turbulent area
smaller. Back in the '70s an uncle of mine attached one to the rear of
his station wagon to keep the rear window cleaner. He swore it helped
his gas mileage as well.

--
We have met the enemy and he is us-- Pogo

Anyolmouse