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Old 07-04-2008, 09:25 PM   #14 (permalink)
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.8 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 73.57 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
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Originally Posted by aerohead View Post
That 2.5:1 teardrop can serve you as a template for a proper roofline profile.
I found the teardrop image in your gallery:

It may be a distortion in the photograph, but that image is actually more like 2.7 to 1. So I corrected it back to 2.5 to 1 in photoshop (not the original - just the following picture) and then followed your instructions to compare these cars:

Your CRX is the closest example of following the shape.

Most surprisingly, the excellent GM EV1 is the furthest from the "ideal" profile!

Kamm's own design follows very closely up to the last 20% of the roof line where it dives down. (All these cars - except mine - are in your gallery ... "other vehicles 1 & 2".)

And for my design, it's not perfect. It's not very clear from this picture, but there's a diverging gap between the cardboard and the teardrop "outline" roughly comparable to the Prius & Insight examples. I'd still like to tuft test it before raising it up though.
Latest mods test: 15 mods = 15% MPG improvement: A-B test, 2007 Honda Civic 1.8L, 5-speed
Ecodriving test:
Manual vs. automatic transmission MPG showdown: Nissan Micra 1.6L

has launched a forum for the efficient new Mitsubishi Mirage - fuel efficiency info for Geo Metro owners - electric car conversion on a beer budget
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