What is interesting to me is two things. First 38mm are far superior in pressure. The 86cfm panaflos and Ultra Kazes @ 2000 RPM have superior pressure over the SilverStone even though they operate at a lower RPM and have lower CFM ratings. Second is I ran one experiment with stacking two Yate Loon medium speeds and nearly doubled the static pressure.
This would indicate that stacking of 25mm fans is a good means to adding static pressure, and also that you're better off with some lower speed 38mm fans instead of 25mm types.
I wanted to take this testing a step further and see if I could plot a full curve with the setup below, unfortunately I'm finding that a 2" ID globe valve and the anemometer is far too restrictive. Even with the valve open fully, I'm already restricting the fan down to about 1/2 of it's rated CFM, so this setup could only capture the first half of the performance curve and I'll need to rethink my approach to testing. Oh well, good thing I went with the cheap $12 PVC valve instead of the $35 brass one I wanted to get..:)
More tinkering to come.....
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