bcgardner wrote:

----- Original Message -----
From: "Paul" <rotaryeng@earthlink.net>
Sent: Friday, September 01, 2000 11:46 PM
Subject: Electric cooling fans

bcgardner wrote:

Paul,

You wrote: "You will have to stop the fan blades from spinning when the
power is off to the fan motor."

While I can see that this would be a good idea in order to reduce wear

on

the bearings, are there any other reasons for doing so?

No but it will really zing at 200 MPH due to dynamic pressure
being 104 pounds per square foot as opposed to only 26 pounds
per square foot at 100 MPH.

Paul, while still intending to take your advice to figure out a way to stop
those blades from spinning, doesn't the difference in dynamic pressure imply
that there is a "right" side to put a fan on a radiator?

If one put the fan on the side away from the natural airflow (a puller fan
rather than a pusher), wouldn't the fins and core of the radiator serve to
diffuse and slow the airspeed to more manageable or less harmful levels?
Couldn't that be a general conclusion about placement of fans to assist
cooling?

Barry Gardner
Wheaton, IL

Yes I would put it on the back side but Jim Rahm put them on the front side as
he had more room there probably. 

BTW the dynamic pressure drop won't be a whole lot through the rad. Right at 
the moment I don't have those numbers.

Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org