Quote from: Geiger on June 06, 2015, 12:51:56 PM

Quote from: NotFuzzyWarm on June 05, 2015, 10:49:39 PM

Quote from: Evan on June 05, 2015, 09:25:03 PM

Quote from: Geiger on June 05, 2015, 08:24:25 PM

Quote from: Evan on June 05, 2015, 04:41:14 PM

Max be 239CFM That's very close to my Big boy deltas I use to cool my radiator for my OC i7 3930k~ 4.7ghz.....
Whats the Air Pressure? My delta at 252CFM is: 1.412 IN H2O 35.877 mmH2O

What do you mean by "1.412 IN H2O 35.877 mmH2O". I'm sure you make sense. It's just that I know the lingo.

1.412 Iches of H2O
Or
35.877 milmeters H2O

Often called a 'head' of water

It is the pressure required to support a water column of the specified height. It is equivalent to 9.80665 Pa, using the equation:

P = ρ·g·h/1000

or TL/DR how hard the air coming from that fan is pushing

It refers to how much resistance the fan can overcome while moving x-amount of air. In our case, the resistance comes from pushing the air through the narrow passageways of the heatsinks. Another term for it would be back-pressure.

The higher that resistance the harder the fans has to work to move air through it.

Fans for miners or any other device with high-density fins on the power devices have to over come a substantial back-pressure to be able to move the required airflow through the heatsinks.

By and large to produce high pressure a fan either A) has to be fairly thick to control how much air leaks between the fan blades and the housing. Is why most PC fans @ 25mm thick suck at producing any real pressure. Miner fans are generally >35mm thick. Or B) the other way to get the pressure is speed. Put the 2 together and yer Golden.

You guys seem pretty knowledgable. How would 2 fans stacked together work? Twice as good, waste of a fan or total disaster?

Fan stacking is more marketing hype than a viable cooling technique, dont think you can get twice the airflow if youre lucky, MAYBE an additional 20%.

When stacking two fans, the theoretical max airflow will be the same, but theoretical max pressure will double. From what people are saying about how small a performance increase they get, one could guess the airflow with just one fan is closer to max airflow than to max pressure.

So stacking a fan doesnt help much. Adding a fan in parallel would more likely help, but the airflow will far from double. This is because to double the airflow through an obstacle, one must also double the pressure (so actually 4 fans are needed).

https://www.youtube.com/watch?v=VUbpb23yTK8

Also you'de be better off setting the case to "push/pull like this out <*#s5#*< in That way the air in and out is balanced and they are not fighting or creating areas of high or low pressure...
The biggest loss in the airflow game is unbalanced airflow in & out of the case. If you put in too much air you create a high pressure zone in your case and the fan has to fight this pressure to get the air across the fins. This is why sealing the top of the case result in lower temps.

I personally helped a friend using Duct tape and Plasticard build a "lid" for his S5.. it dropped for him over all 2 degrees but that was with a single fan and not the push pull as described. More important for him it made for a Quieter over all system.