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I may have read it wrong, but it seems the NACA study that Tracy was
referencing said that the cooling drag for the Aztec they were testing
was about 5% to 7% of total drag. I've read before that cooling drag is
more like 30% of total drag. Big difference there it seems.
E
I have heard the 30% of total drag as cooling drag but it applied to CLEAN airplanes. The Aztec is no biplane but does not qualify as 'clean' . 5 - 7% still sounds low however.
T
On Sat, Apr 30, 2011 at 11:10 AM, Ernest Christley <echristley@att.net> wrote:
Ed Anderson wrote:
For a high speed cruise environment, I would think cooling drag might be of more importance than say perhaps a few pounds of additional weight, on the other hand if you are flying an already draggy biplane for example, cooling drag is probably a very small part of your over all drag, but getting cooling with low airspeed might be the system driver.
Its all about compromises - space, weight, flow, drag, etc. - oh, yes! - and cooling of course {:>) all matched to your constraints and operating environment.
I may have read it wrong, but it seems the NACA study that Tracy was referencing said that the cooling drag for the Aztec they were testing was about 5% to 7% of total drag. I've read before that cooling drag is more like 30% of total drag. Big difference there it seems.
Does anyone have any better insight, or is this just an apples vs oranges thing? We've spent a LOT of time discussing cooling drag on this list. Is it even worth worrying over? Is it worth stressing over an engine overheating to go 196MPH instead of 192MPH?
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