"Biedermann, Frank (SSABSA)" wrote:
>
> Derek & Joe,
>
> I think you might be overlooking the most important aspect
> of this sort of idea - the airflow that the fans produce. I
> suspect that you would find the 14in (or whatever size the
> automotive fans are) have a much larger capacity to push/
> pull air around than 12 of the little fans.
Another consideration when trying to engineer fans is the nature of the
fan specs, which is sometimes hard to pry out of the manufacturers.
Simply put, most of the so-called muffin fans (which I think is what was
being described originally) use a "free air" CFM rating, which means,
simply, that the CFM stated is correct when running without obstruction
at the inlet and the outlet. In order to determine the true output of
the fan, it has to be rated according to the pressure drop in the actual
installation.
The radiator itself is an obstruction to airflow, which creates a
pressure drop, and therefore, if the fan is rated in free-air CFM, its
output will be considerably lower when trying to push air through an
obstruction such as the radiator (or trying to pull air through that
same obstruction).
Cheers, all.
--
Michael D. Porter
Roswell, NM
[mailto: mporter@zianet.com]
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
|