[DeTomaso] What diameter sucker fan?

[JDeRyke at aol.com]

In a message dated 5/7/10 1:30:23 PM, kenn_green at yahoo.com writes:

> What is the preferred and/or largest size sucker fan that will fit a 
> layed down radiator?
>  Thanks,
> 

25 years ago, I borrowed an anemometer from my workplace and tested our 
stock Pantera's pusher fans. The air flow out the back of the core was a max of 
300 cubic feet per minute, apiece. This figure is often quoted but it was 
only a single parking-lot test. The Flexilite dual sucker fans are advertised 
to move 1200 cfm apiece. Coincidently, the Flexilite shrouded dual-fan 
assembly fits a Pantera radiator (stock or aftermarket) almost perfectly. If you 
measure your radiator, the core is 14" x 26", so two 13" fans are very 
close to the maximum size that can easily fit. A shroud around 13" fans didn't 
significantly restrict air flow thru the rad at high speeds but smaller 
shroud-holes for 11-1/2" fans did on our Pantera- which slowly heated up over a 
10 minute run at 140 mph. How fast the fans spin and to some extent the blade 
design determines the amount of air that can be moved per rev. A shroud can 
definitely help, especially if the blade tips are sunk in only about 1/4- 
1/3 the blade-tip width and the blades are not very close to the core. A drop 
in voltage from 13v to 11v due to line resistence seems to reduce airflow 
by about 25% regardless of how big the fan motor is, according to one web 
site. FWIW- J DeRyke