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Old 08-24-2011, 12:30 AM   #60 (permalink)
PeterS
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Join Date: Aug 2011
Location: East coast of Australia
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Yella Peril - '80 Mercedes 240D sedan
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Quote:
Originally Posted by dcb View Post
That is a highway only perspective, that isn't how we all drive, at least not predominantly. In the city (where most of us spend much of our lives) it is mostly about technique (accelerate efficiently, don't overdo it so you have to brake, don't use your engine if you don't have to), and weight, especially from a "make the most of what you have" perspective.

the AERO HP in that calculator at 25mph is 1.7, at 70mph it is 18.57, over 10 times more. Where rolling resistance went from .98 to 2.73. The benefits of aero are a function of speed, and can make parallel parking a b$tch.

This isn't THAT complicated. I'm not saying Craig should change the contest, just the rhetoric.
Well ,seeing the thread is about Craig's challenge I can only repeat that if 70mph and 120 mpg are the goals very good aerofairings are the only way .Big engines give the 70mph easily but at 70 mph a bike with a cD of .75 is using 20hp and getting 45mpg .
Lower the cD to .35 with the same fA and the same bike gets 90mpg and uses 7hp to stay there .That leaves a lot left over for acceleration and climbing hills .

Aero drag is everything !
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