RE: Lighter Wheels and Radiators AD V7 #929

["Jorge Mazlumian" <jmazl@domain.elided>]

Michael in Calgary wrote:
<<Ford designed a very clever radiator grille many years ago for their
little Fiesta. At highway speeds the spacing and shape of the horizontal
grille bars caused the air gaps to progressively close up aerodynamically,
leading to consistent flows at any speeds for cooling and minimizing drag
from too much air entering the engine compartment.>>
****
Hmmm! what is the drag coeficient of a Ford Fiesta?  The principle is sound,
but applied to a Fiesta?  Its a brick on wheels with a little engine.  May
be I'll design a grill for my Milano.  Anybody can let me use their wind
tunnel?  Actually I did tinker with a '88 grill, replaced the plastic
horizontal bars by a perforated sheet of metal (more holes than metal), but
before I could measure the drag coeficient the car was totalled.  It was too
fast!!
********************
<<The air should ideally all be deflected around the bodywork (ever wonder
why Le Mans cars are so much faster than F1 cars, less drag from the
envelope body). But this would
cause drastic overheating at speed.
Shoot, want to get sophisticated, tilt the radiator forwards at the top and
put extractor grilles in the hood, then at least you'll be getting some
down force from the thermal pumping effect. How much faster did you say you
wanted to go?>>
****
There is a nice issue of Race Car magazine with a racer 156 on the cover.
The article inside describes to certain extent the design of various parts.
It's a car built for racing from scratch by the guys at Alfa.  The radiator
post-air is tunneled out of the engine bay, to avoid drag.
The front lower spoiles is ducted on the sides to the front brakes.  The
bottom of the car is almost flat.
So I see what you mean, Michael.  If more air enters the bay, it has to come
out just as easy, but that is my point.  Can we rout air through the bay and
out, cooling in the meantime the headers, or the ABS system.  I say it
again, my car is not a rase car, it's a fast street car, that has to deal
with Southern California summer and traffic.
******
Dave writes:
<<The main reason for the sheet metal along the sides of the
radiator in any car is to keep hot air from being drawn
around the sides of the radiator from the engine bay by the fan.
Venting the bay somwhere else may work if you don't
mind carving up your Milano but I wouldn't mess with
the side panels along the radiator.>>
****
Agree, but wouldn't that be the circular plastic encasing of fan in the more
modern (or not) cars?
Certainly I don't want to bypass the radiator, sucking air from the sides.
But if the sheets on the sides of the radiator are intact, then the fan
would suck hot air from the engine bay! If anything it needs sheets on the
side of the fan, not the radiator.  That should be a fan enclosure.
Fiuuu!  So much heat and my brain is shot.

Jorge
89 Green Cloverleaf (4 leaves)

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