[Elecraft] Exhaust Fans

[Don Wilhelm]

Joe,

If the fan is to cool a large area like a heatsink, it is better to 
exhaust the air rather than blowing it in.
Only in the case of where the fan should blow onto a relatively small 
area would it be wise to direct the flow inward.
In the case of the K3, the fan should exhaust the air.

There is another subtle factor as well.  A fan creates "work" in moving 
the air and that "work" produces heat.  If you examine the temperature 
on the outbound side of a fan, it will be higher than the incoming 
airstream.  A principle of fluid dynamics that is not often considered.

73,
Don W3FPR

On 2/11/2017 4:23 PM, Joe W2KJ wrote:
> Howdy Fellow Elcrafters:
>
> Been reading the posts about fans for the K3.
>
> So here’s my dumb question for the week.
>
> Are there fans specifically designed to exhaust hot air from radios as opposed to fans that blow cool air into the radio?
>
> Or is it simply a matter of turning the fan upside down to go from  “blow in” to “exhaust out”??
>