Quote:
Originally Posted by aerohead
Neil,once the boundary layer goes over to turbulent the Cd is fixed for a body up until around 250-mph for cars,when compressibility issues come into play. Angles, good at any sub-transonic velocity will not alter drag anywhere within this velocity domain.
In fluids,the barometric pressure will affect air density,which is part of the drag equation.
The pressure drag,which is what we're going after,is ruled by separation.If you can eliminate separation you've eliminated pressure drag.
If you get an angle which will work at 25 mph,she'll still be good at 225.
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That is a nice rule of thumb. The 25-250 mph regime is good to know. I thought that was about the lower bound but had no idea about the upper bound. Thanks, Phil!