Quote:
Originally Posted by ennored
While I agree with your statement, also remember it doesn't have to sacrifice much to be quite aerodynamic, nor does it have to "look" aerodynamic.
Best example of this is the Vixen motorhome. It had an actual Cd around .30. But, to most folks, it is still a box. ..............
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Thanks for posting the Cd, did you reference a source or just go off memory?
The roof taper is appearing on many vehicles today without much fanfare or acknowledgement to aerodynamics, this somewhat stealth introductory of aerodynamic design will eventually mark flat roofs as antiquated I suspect.
We are not seeing a lot of tapering in plan outside of hatchback and crossover greenhouses, and you really have to look for it. The smaller Volvo's and the Juke come to mind.
The Vixen and other larger RV's benefit from a longer length ratio to lower their Cd as much as anything else going on.
However, what we are studying here and I suspect will be seeing more of in the future is taller height to length ratios that will have to resort to tapered roof profiles to maintain any kind of fuel efficiency.
The hinged and telescoping roof schemes are an attempt to skirt around the height issue and get a more friendly length ratio.