Subject: Re: Elastic air and inertia AD V7 #877

["Sedon, Doug (OD/ORS)" <sedond@domain.elided>]

hi greg, ewe said:
>Of course--the older Alfa Veloces had this figured out far earlier, even
>though their air source was under the left side eyebrow. One very
>interesting aspect of the aerodynamics of these older Alfas is that the air
>pressure against the firewall _under_ the hood is actually HIGHER than it
>is at the base of the windshield on the outside of the hood!! This speaks
>pretty eloquently to the effectiveness of the front radiator and eyebrow
>intakes on these cars!
>
>If you do not believe what I am saying about which pressure is higher, try
>driving one of these cars with broken (or missing) hood hinges faster than
>about 85 or 90 mph, and watch the back edge of the hood lift up!!
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mebbe i'm missing something here, but i always thought the raising of a
front-hinged car's hood (or front trunk!) was due to the fact that the air on
the car's outside is moving much *faster* than the relatively still air on the
inside, not the other way around.  it is the vacuum effect of the faster-moving
air on the outside that causes the hood to rise.  sure, the air pressure inside
is technically higher than what's outside, but not due to any ram-air effect
thru the radiator/eyebrow intakes/etc.  if the airflow thru the front
radiator/intakes/etc. was greater than that on the outside, then, in fact, the
hood would remain *closed*.

both my gtwe6 & my de tomaso pantera exhibit this trait of the back-end of the
hood/trunk lifting up at speed.  the pantera has absolutely *no* airflow thru
its front trunk, either - the radiator compartment in front of the front trunk
is *completely* sealed off...  

ciao for now,

doug s.

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