Quote:
Originally Posted by aerohead
It' raining today and I walked here without my briefcase,so no calculator.Sorry.
Here's a graph for a car of 22-sq-ft frontal area and 3,400-lbs curb weight.
Looking at the right hand side you'll find a line for Cd0.10 which is close,and you can compare the road load to that of another Cd.
If the BSFC is maintained through gear-matching,then the new fuel consumption will mirror the reduction in road load.
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Here is a road load curve for HONDA's Dream-2 solar racer,of Cd 0.10,a lightweight tandem,maybe 9-sq-ft frontal area (I'd have to look).
You can see that at 100-mph,it requires less than 6-kW to move it.That's a 300-mpg car!
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This touches on something that I've been wondering about for a while.
In an effort to reduce fuel consumption to meet CAFE standards, manufacturers have been trying to reduce drag by chipping away at Cd. But equally important is A (frontal area) and that has typically been increasing, year over year. The XL1, for example, has a great Cd, but the small frontal area plays every bit as much of a role in it's fuel efficiency.
I suspect this may be a trend that we will start seeing too, especially as the mpg targets get harder to meet.