Quote:
Originally Posted by NeilBlanchard
(emphasis is mine)
This is exactly what I was thinking -- if the sides tapered in, then the air on the side would be more likely to stay on the side and therefore reduce the lifting vortex. Which would mean less drag... Air flow is 3D.
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Neil,if you had Fachsenfeld's book you'd see Kamm's wind tunnel models doing exactly as you describe it.It is exactly what's going on.
Elsewhere in the book you'd see how Walter Lay 'fixed' it with plan taper.
All else being equal,the difference between straight sides and tapered sides is Cd 0.21 vs Cd 0.12.
This is why conventional 'teardrop' trailers are incapable of truly low drag.And this is also why some messengers make the comment that 'just because it looks streamlined doesn't mean it IS streamlined.'
Good call!