RE: Automotive Aerodynamics [WAS:90 90q

[Alexei M Voloshin <Alexei.M.Voloshin-1@tc.umn.edu>]

Your aero-drag fromula is only an approximation. The results you get from 
it can be off by as much as 40%!

Alex

On Wed, 19 Mar 1997, Paul Heneghan wrote:

> 
> Thanks for the info Tamas.
> 
> Just one question.
> 
> I calculate that for an Audi90 at 125mph (55.9m/s), the drag will be 1366N 
> (using Cd = 0.39 and FA = 1.87).
> 
> The power to move the car at this speed against this force is P = F x V
> 
> This gives 76kW.
> 
> Most engines for cars that can do these speeds are putting out about 100kW. 
>  Surely 25% cannot be lost in friction?
> 
> Any suggestions?
> 
> Paul
> 
>  ----------
> From: Bertenyi, Tamas
> 
> Ok, well since you asked...I'd love to go on about automotive
> aerodynamics! To begin with, let me give you a few more drag figures.
> <snip>
> 
> Audi 90/2.0 E,      Cd=0.39, A=1.87m^2
> 
> <snip>
>