Quote:
Originally Posted by brucepick
Those cars that have a truncated teardrop template design such as Prius and Insight have very low cd as a result of it. If the same or better cd could have been gotten with a notchback, even a modified notchback of some sort, I'm sure the designers would have gone that route, and would have had a much easier time selling cars with a more conventional design.
So my guess is - whatever the reason, a body that follows the template actually does give lower Cd than a notchback with carefully tailored curves and angles.
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Exactly. From AeroHead...
"*The best 'idealized' spoiler could have significant potential for drag reduction,although due to the turbulence associated with the separated flow above the spoiler,it could never achieve the drag reduction of the K-form 'Template' roofline, which is devoid of such turbulence.
*Turbulence cannot be converted to useful pressure regain,only heat,during viscous attrition as the eddies are eventually worn down by calmer surrounding air. It's a second law of thermodynamics thing we strive to avoid."
In a perfect low drag/high mpg world, we would all drive cars that taper smoothly to the rear like a 1/2 ice cream cone or Dave Cloud's Dolphin "Ultimate Aerodynamic Car" but compromises are made for length, styling, parking and visibility. So we end up with counter-rotating vortexes adding drag to our cars. I am excited to see California98Civic testing some ideas and seeing some improvement. It is a step in the right direction but still a compromise.
This would be better IMO but not too practical for most people.
http://ecomodder.com/forum/showthrea...-ii-13037.html