William Adkins wrote:

Paul and All,

Just had to get in on this one.  As I make my own props for my LongEz I
read all information available when this dimple  theory first came about.

I had been in on a lot of drag reduction tests in NASA's wind tunnels,
including
some on using sound (that one actually worked, I still have the
picture-proofs)

At any rate a few things did not seem to jell in my old jello-head so off to
the
testing.  I had a prop I no longer used (commercially purched) which I used
for
 the experiment.  Had to invent a few methods of getting the dimples spaced
properly
and the depth exact.  Having solved those minor worries I proceeded to
desecrate
(spelling) a perfectly good prop.  Looked almost exactly like the one
pictured.

On to test day:  In a word 'NOTHING'.  No improvement in take-off, or climb,
or cruise, or top speed.  Fact is it seemed to add a bit of drag to the
prop.

Some facts to ponder as I did before the test:  A row of dimples does
distrupt flow, ie
vortex generation.  A row of vortex generators in front of another row DOES
NOT
work.  Three rows--- wellll!  Vortex generation does nothing after velocity
gets to a
certain point. Pretty sure the air does not have time to reattach to a propo
blade with
dimples down the certer or any where else.

Two cents spent--nothing left. Except I have a prop for sale, for a
0-235-L2C.

Fly fast, land slow.
Bill

 
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