A big "Thank You!" to jrlii! That document you linked did a good job of clearing up some confusion that I didn't even realize I had
It looks like the ComairRotron impellers I found at AllElectronics were "reverse" blades. According to that doc, these are best suited for suction, and, luckily enough, that's what I did with one of 'em. No
wonder it worked fine without a housing. This means my previous statement about cage fans working fine for suction was an over-generalization on my part. Apologies to anyone I mislead with my ignorance.
As a "low noise" guy, I'm still interested in the JapanServo cage fans. I found some interesting air flow diagrams in this
JapanServo cage fan brochure
This first is for a forward "sirocco" styled cage
The second is for the JapanServo modifications to it to lower noise output.
I find it interesting how the first part of the longer blades looks pretty much like
reverse blades - that then turn the air "forward" with the aid of "helper blades" - and none of the blades curve forward as much as the "forward" blades in the first picture.
I'd still love to find a 5" or 6" JapanServo cage fan. If you run into one on the net,
please let me know. Thanks!
Bob