RE: a drag question

["Wickes, John" <JWICKES@COSMPDAERO.CO.SYMBIOS.COM>]

After work I went home, dug through a physics book and answered my own 
question. Yes, drag force D decreases with air density ( fluid density, 
rho), drag coeffecient C is a constant ( duh). S0  force eq looks like 
Fdrag= 1/2(rho)ACv^2, where rho can be tweeked by ratios of atmospheric 
pressure, same as multiplying C or final answer D by the ratio. thanks,john 
wickes
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From: Wickes, John
To: evgrouplist
Subject: a drag question
Date: Sunday, August 30, 1998 4:09PM



     Would an increase in altitude result in a decrease in the coefficient
of drag 'C'? I think it would!

     As an example, I live at 8500 feet above sea level where the barometric
pressure resides around 600 torr. Where I will drive to work is 6000 feet
above sea level where the barometric pressure resides around 690 torr.
     Could I take the difference in altitude that  as a percent difference
in the coefficient of drag ( like we do for the boiling point of water up
here ) .
so at 8500 feet up
600torr/760torr =.79
if drag = .3 at sea level then at 8500 feet drag is
.3 (.79) = .237

and at 6000
690torr/760torr=.91
if drag = .3 at sea level then at 6000 feet drag is
.3(.91)=.273

cool eh? I thought of that while I was running some numbers through the Uve
Rick ev calculator.  But because I will be going slow back up the hill
(40mph) it does not improve the range all that much.  Just a thought..john
wickes