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RE: Aerodynamics

To: "Benn" <karhu@california.com>, <land-speed@Autox.Team.Net>
Subject: RE: Aerodynamics
From: "Dave Dahlgren" <ddahlgren@snet.net>
Date: Wed, 26 Jan 2005 16:08:27 -0500
I bet there will be a lot of people not very happy about this news..

BUT I got me a plan Hoss.. From the ciphering I have come up with the
following
Changing the ride height by a factor of 10.526(4"/0.375") you gain a Cd
reduction of 0.714 (0.25/0.35) Soooooooooooo
We are running the Berkley at around 1" in the front and 2.5 in the back so
there will be some changes going on and like all good theories I would like
to test the limits so I am looking to reduce the Cd by at least 75%.. here
is the plan it is pretty tricky so follow close..
If I raise the car to 10.526" in the front and 13" in the rear the Cd will
go down to 0.25 but I want more so I will take the next step..I will use the
same ratio and raise the front to 110.80 that is another X 10.526 but the Cd
will go down another 0.714X the old one so the new Cd is 0.1785.. But I am
greedy so lets do it again..110.85 X 10.526 is only 1166.280.. and the Cd
goes down again to 0.1275 I think I can be happy with that but tires will be
a problem though gears will be easy..With 97 ft of ground clearance
servicing this may be a problem as I have an issue with heights..I think I
better stay at 9ft 4 and suffer the losses...At least the nose bleeds will
stop....
At the end of the day this sounds like a bunch of quotes all out of
context??? Show me the first high speed vehicle that wants to run 4" ground
clearance and then I might be a believer..
Dave

> -----Original Message-----
> From: owner-land-speed@autox.team.net
> [mailto:owner-land-speed@autox.team.net]On Behalf Of Benn
> Sent: Wednesday, January 26, 2005 2:47 PM
> To: land-speed@autox.team.net
> Subject: Re: Aerodynamics
>
>
> If the nose is on or below center of WHAT?
>
> And all the lsr cars that have about an inch of ground clearance at
> front are sustaining 40% higher drag than if they were 2-1/2" above the
> ground?
>
>
> > >
> > >      The front half of a streamlined shape has a minor effect on its
> > > drag.
> > >      A shape that had a Cd of .25 and 4" ground clearance would have
> a .26
> > > Cd if it was 2 1/2" off the ground and .35 Cd if it only had 3/8"
> clearance
> > > .
> > >     If the nose of a car is on or below center the drag will be the
> same
> > > and the low nose has down force - If the nose is above center it
> will cause
> > > lift and have more drag .






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