Quote:
Originally Posted by Thenorm
do you mind if I summarize this a little clearer.
1. for good Cd with no modification, get the sedan
2. if you plan to add a kammback/boat tail for remarkable drag reduction get the hatch.
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*The sedan has been optimized as a sedan with no thought of modifications.
*The hatch was also not designed with mods in mind,but happens to have the perfect fundamental architecture if one wanted to do the ideal elongation.
*All the really low-drag vehicles which have been constructed were 'fastbacks',which followed the profile of a proper half-streamline body.
*If you continue the roofline and sides of the hatch,you're right on target for low drag.It's exactly like Kamm & Koenig Fachsenfeld's Cd 0.12 Kamm-back in it's embryonic stage.
*The Cd will just be a function of how far back you push the tail.
*K&K cut their tail off at 50% frontal area cross-section and got as low as Cd 0.23 with a 'practical' length in the late 1930s,early 40s.
Then Koenig-Fachsenfeld came up with the inflatable boat tail extension to push the Cd back down towards 0.12,for only open highway travel where length wasn't an issue.