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RE: Squareback racing?


FWIW -
While I was doing my Engineering stuff at school, I couldn't decide
on either Mechanical or Aeronautical, so I mushed them together.
So I took courses in both areas.  One course was on vehicle
stability, another on aerodynamics, wind tunnel lab, etc.

One formula we had was to determine the top speed of a vehicle
given the HP, drag coefficient, frontal area, etc.  (lost the formula)
Using my '67 Sqbk as an example, we calculated that the top 
speed would be 84 MPH.  I tested the calculation shortly 
thereafter, it was true! I maxed out at 84 MPH!

Anyway, surprisingly enough the most important factor in 
determining the aerodynamic efficiency was the TAIL end of
the vehicle.  The front was a big dam, regardless of it's shape.

A wedge shape with the big end up front is more efficient than
with the pointy end front.  The drag is caused by the turbulent
air pulling back on the tail of the vehicle.  How the air gets to 
the back is less important.

As for Squareback vs. Fastback.

I suspect that the difference in drag coefficient is negligible, 
(speaking as a Squareback owner), but for Fastback owners
there is an argument for better factors.  The back end on a 
Squareback is actually sloped and not square anyway.

A notch is probably the least aerodynamically efficient, with 
two changes in shape at the rear.  But the differences
between all three being still negligible!

This all leaves out the downward forces needed to keep the
vehicle from flipping front over back.  Thus compromises
in design shape are made!

- Jeff  '67 Sqbk
 

> > It seems that someone asked what the best possible aerodynamic
> > shape was.  After some work it was determined that it was 
> > approximately a cigar shape, but for it to be large enough for a
> race 
> > car, it would have to be 40' long.  Of course this leads to the 


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