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Old 08-19-2017, 07:26 PM   #4 (permalink)
s_t
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Join Date: Aug 2017
Location: Brisbane, Australia
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Quote:
Originally Posted by aerohead View Post
The Vixen,5-cyl BMW Diesel-powered RV motor home could get as high as 29-mpg at around 55-mph.
Thanks, hadn't seen that before. Size is similar to what I'm looking at (mine slightly smaller perhaps). It's Cd is less than 0.3 according to Welcome to Vixen 21 Motorcoach Website. Makes me wonder how much the teardrop shape on the roof profile, that I was planning for aerodynamics, would improve it - if at all??? Also found a link to the NASA study Inter Action which indicated good results by just by adding a boattail.

That roof profile that I sketched ended up being pretty close to the profile discussed http://ecomodder.com/forum/showthrea...-c-9287-1.html, but drops slightly more steeply near the end. This shape would be 'less usable' during motorhome use - simple square provides more interior space and would be easier to make too. Has anyone seen a motorhome following a more optimised profile along these lines?

Quote:
Originally Posted by aerohead View Post
VW Jetta TDIs,pulling up to 19-ft Airstream trailers have been reported at up to 30-mpgs.
I hope to test a trailer next month in the wind tunnel.I can't tell you anything 'til that's over.
Member BamZipPow has done a lot of trailer testing with his Toyota pickup.If you haven't seen his 1-wheel trailer thread you should check it out.
Will check that thread out. Sounds like similar efficiency is possible either way - one piece motorhome or car pulling trailer, but perhaps the trailer option requires a little more optimisation. Look forward to seeing the wind tunnel results.
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