Quote:
Originally Posted by ennored
I'm still a bit lost with less than optimal tails though. How come the Dryden van tail looks to have attached flow?
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I don't want to speak for Aerohead, but as I understand it the Dryden van with all treatments and modification combined achieved a 15% improvement over that of the stock Econoline van. There is a PDF paper or two which might define which part of that is the boat-tail alone.
This 15% improvement I assume is a far cry from an optimum 3D teardrop shape.
The flow attachment is one thing, but once it lets go of the body, there could be aerodynamic retribution (back lash) over that of a more gentle slope preceding termination.