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<< Depending on your age, your undergraduate textbook may have used a
Piper Cub, C172, or Beech 18 for the "typical" example. When extensive
natural laminar flow is achieved on the rest of the airframe, drag might
be reduced by quite a margin. Thus, cooling drag may be a much greater
fraction of the total drag on a slippery Lancair. I wouldn't be
surprised by 20-25%.>>
Bob,
You are correct.
The faster the plane can go based on airframe aerodynamics, the greater
cooling drag becomes percentage-wise. I couldn't find a good summary of
GA aircraft cooling drag values(Does anyone have this info??), but I do
have numbers on my 360. The attached chart compares stock cowl+baffle
(~14%) to new cowl+plenum (~7%). We are definitely more sensitive to
cooling drag than the Piper Cub.
Chris
Chris Zavatson
N91CZ
360std
www.N91CZ.com
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