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Date: Tue, 06 Dec 2005 15:03:29 -0500
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From: bob mackey <n103md@yahoo.com>
Subject:  Re: [LML] Airfoil Surface Roughness
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The CAFE report on waxing a Mooney and gaining a few
knots is interesting in that it has actual data
from actual flights. There were not enough flights to 
determine experimentally the range of uncertainty
in their measurements, but it is much better than 
most of the hogwash that gets bandied about. 

[ Note that "data" is not the plural of "anecdote". ]

For a much more comprehensive view of drag reduction, 
see: 

Personal Aircraft Drag Reduction
by Bruce H. Carmichael
(Published and sold by the author, 34795 Camino
Capistrano, Capistrano Beach, California 92624, USA:
1995)
195pp, 195 illus., 26 tables, refs. Photocopy, 1/c,
Velobound. US$25 postpaid in USA, $28 Canada, $33
Western Europe, $35 elsewhere. )

http://www89.pair.com/techinfo/Books/bookrev.htm

ahhh... I see it is now available through Aircraft
Spruce 
also: 
http://www.aircraftspruce.com/catalog/bvpages/drag_reduct.php

PS - golf balls are dimpled because turbulent flow
leaves a smaller separation bubble behind the ball
than would laminar flow. The low pressure separation 
bubble is the major source of drag on a golf ball. 
It could be reduced by changing the shape of the ball,

but then it would be hard to hit straight, and putting
would be especially challenging. 

-bob mackey


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