Getting old and forgetfull: flow becomes non-laminar at "x" degree.. 10? 12? 17?
I've heard all kinds of numbers over the years, but a while back when posting here I finally figured out what the correct answer is. (I know *it depends* on speed, humidity and elevation, but let's say... really really subsonic, like 65mph, 60% humidity and sea level)
And a ball park is fine, I'm building a rear fairing for a street car, not a fighter jet.
"If you want to save gas I suggest you permanently remove the drivers seat and steering wheel. That seems to help." -Oscar Halverson