Re: Aero Testing

[Dave Dahlgren <ddahlgren@snet.net>]

It depends on how bad they drag.. But you are looking for the total drag for the
whole car.. If you fix any of the other things then the results should show up
as well.. What you do not know is the racing surface condition and it has a
dramatic effect on the hp required to go a certain speed. If the surface deforms
it is absorbing power..the extremes being concrete and sand.. So data collected
is valuable but has to be scaled for air density and surface conditions.. The
software I wrote for gear selection takes this all into account doing terminal
speed calcs.. I wonder if I could just reverse the inputs and outputs so it does
a calc on coast down ... Or just add a module for that..

Dave

John Beckett wrote:
> 
> OK here's another thought to factor in to the coast down. How big a factor
> is the drag from the brakes, drive line and rolling resistance. Guess it
> would only be important if comparing coast down Cd to a wind tunnel Cd.
> 
> JB

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