2 fans back to back

[tg900]

I am wondering if you stack two fans, one on top of the other, and they both blow in the same direction, will you have any gain in the amount of air that goes through?

I've thought about it for a bit, and asked some people, and they say that the gain will be minimal. Any ideas with some good reasoning would be appreciated

 

[Yasu]

That probably wouldn't work because they will have the same RPM(assuming they are both the same). You may actually lose performance because air flowing through the first fan will start hitting the blades of the 2nd fan unless they were perfectly synchronized.

 

[Geoff]

I would suspect that there would only be a very slight gain, if any. Lets say there both the same exact fans, if they can move 30CFM of air, then it wouldnt matter if you stacked too on top of each other, since it would only be able to push at 30CFM.

 

[Greggie Boy]

If you have one fan blowing directly into a second fan, no gain, but if i read you right, you mean two fans,upper & lower blowing in same directuion. Yes the is quite a bit of gain, providing you have at least the same amout of fans running as "exhaust".
The more exhaust fans you have will actually assist the intake fans in such a way that they are remving enough air to let the intake fans perform better.
It is much like this:
Your in a building with one front door and two back doors and the breeze is hitting the fron door, For the best cooling of the building you open both back doors to let the air flow through. A nice roof fan would help too!!

 

[Motoxrdude]

You would get some gain, but not too much. Since one fan is moving air, the second fan will blow at a higher rpm.

 

[The_Other_One]

Actually, I hear doing stuff like that degrades the performace...

 

[dragon2309]

to summarize......

 

[doom]

I am wondering if you stack two fans, one on top of the other, and they both blow in the same direction, will you have any gain in the amount of air that goes through?

I've thought about it for a bit, and asked some people, and they say that the gain will be minimal. Any ideas with some good reasoning would be appreciated

NO mate tried that along time ago, you would be suprised what happened, hotter!!!!!!