thanks, you are right

reading supplied link now, I might add it is excellent

Yes, but this isn't what people (myself included) were critisizing you about.
The blade differences dont affect the basic principles of the fans, which you seemed to have wrong:

jlrii - thanks for the link - its interesting. I have a twin Radial "AW" blade type 120VAC blower that i am looking to build into a rad box. Looks like it'll do fine.

Thanks for the link, very nice!

No prob. feels nice to provide info instead of just sucking it up a for a change. ;)

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
http://koure.org:800/temp/TN_cagefan-sirocco.JPG

The second is for the JapanServo modifications to it to lower noise output.
http://koure.org:800/temp/TN_cagefan-japanservo.JPG
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

While I'm at it (and only slightly tongue-in-cheek) if you don't care about noise, for $16 you can get a fan optimized for suction rated at 600CFM (looks like it might be used to provide suction for a "whole house" vacuum.
http://www.herbach.com/Merchant2/gra...01/blr4428.jpg

It might even be practical to but this thing in the basement and use lightweight 3" ducting (often sold in the US as plastic downspout - really cheap) to duct the suction up to wherever you need it...

deleted post

Just ordered some new pieces parts, decided to build a rad box. It "should" be fairly quiet using a "few" of the fans Zogthetroll came up with an a couple of real odd single pass heater cores I found. All going to fit in a Chenbro 19 in 4U rackmount case, with empasis on keeping external air velocities low. Will post pics when it gets put together, which may be a month or so ;) (I'm lazy)

They move plenty of air through a 2" heater core at 12V (actually move plenty down to 7 or 8V but are (IMHO) loud (35 or 38 dB at a guess).
Upon disassembly and inspection, they are not the quiet bladed japanservo fans I was looking for, but a simple forward blade (will follow up with photos - probably uninteresting except that this cage fan pretty much fits where you'd put a 120mm axial fan - two of the three mounting holes line right up with the holes for a 120mm fan).
Bob
PS: anybody want 'em?

Do you mean they're too loud at 7-8v and louder than your L1A's at 7-8v?
Do they move more air than the L1a's at that speed/voltage/noise level?
Will they turn at 5v?

I suppose one advantage of that fan is they could be setup to exhaust out the side of the case easily w/o complicated shrouding.

Actually, the cut off voltage between useful flow and not is at about 9.25V (this for a 24V fan, remember)
At 9.25V it's definitely louder than a L1A at 7V, but definitely not as loud as a M1A at 12V (so somewhere between 25 and 35 dB). It doesn't get much louder until 11V or so. At 12V it's about the same as the M1A.
It's too loud for me (editorial comment).
It seems to suck/blow plenty of air at 9.25V. Attaching the radiator to the shroud doesn't seem to make much difference (so enough pressure that it isn't an issue pulling air through a 6x6x2 core)
I'd been hoping that these blowers would have the japan servo "silent" blades (sort of a cross between reverse and forward blades with helper blade-lets to help with the transition). They did not.

Anyway, it's a convenient sized package to mount on a coolshroud
http://koure.org:800/temp/TN_PIC02112sm.JPG

and here's a picture of the blades
http://koure.org:800/temp/TN_PIC02116sm.JPG
Note how they're cupped forward.

I'd love to see how a similarly sized package with the reverse/forward blades might do. From the JapanServo brochure it might be the SCBD or E1540 series.

I wonder if JapanServo would be willing to sell these in "quantity one" to a hobbyist...?

Here's the Nidec Gamma 30 I referred to earlier. Im using it to cool my biological processor. ;) Hazy summer days in FL can be hell while idling in traffic on my bike. This really helps.
For regular PC use its a bit noisy compared to a comparable sized axial fan, although it does put all the output air in a small "footprint" ( good for heatsinks )

too cool, LOL

At one point I had an AGV helmet with a pelt built in - heatsink along the top ridge of the helmet and a gel bag that sat on top of my head.
It worked - although where I would really have appreciated the extra cooling was on the track - and this helmet only had DOT (needed Snell M85).
No picture - sorry...

actually,the way it's set it will suck air through the rad then over the motor and then the air will slam into the sides of the case.

How do those sound when downvolted a tad?

Theres a noticable whirring noise at 12V, but you can turn it down to a reasonable level. I used a lower voltage to run mine at 1600RPM cooling an XP1800. Mine wont start at under 7 volts, but it will run at 6 (not that it would move much air at that speed, its just an example)

http://mactree.sannet.ne.jp/~kodawar.../imacg502.html

New iMac using blowers for it's cpu.

This was from ./ so be patient.