Quote:
Originally Posted by diesel_john
A side effect of this shows that shapes and components developed for airplanes DO scale to lower speeds.
I don't understand entirely
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A quick example would be if you had an airplane airfoil that is 3x larger than you want for your car you do something like the following:
(1/3 scale factor) * (23.77/7.382 average density at sea level divided by 35,000 ft, scaled) * (60/600 grossly estimated traveling speeds) * (drag on airplane airfoil) = drag added to your car
Also if you only scale, preserving geometric relationships, then the coefficient of drag will not change on most of the sizes we would be discussing. Since you are considering scaling down size AND speed it is especially true. As you decrease speed the secondary layer flow decreases - the area where the fluid sheers off a surface, slowing down. This explanation is probably more than necessary I now realize
