Making 'complex' fan adapters: Excel sheet included..

niels007 · Post by **niels007** » Mon Mar 14, 2005 5:28 am

Hey all,

Probably of little use to most, but perhaps a few guys could benifit from this...

It isn't really straightforward to make a cardboard (or other material) fan adapter from 120x120 to 90x55 with the target being offset from center. What are the exact dimensions for the 4 sides of such a fan adapter for a given 'height' of the adapter? Takes a while doing pythagoras calculations..

I've made an excel sheet where all the dimensions are variable, including any offset for out of centre targets. So if you want to go from 120x120 to 80x80 with the height of the adapter being 40, or you want to go from 160x120 to 80x60 over height of 100, it is all possible!

http://members.home.nl/taselaar/niels/adaptersheet.xls

The sheet is tested and works with my new adapter that had to be off centre as my new mainboard has the cpu socket in a different location, and my side panel fan hole is rather permanent..

Be sure to mention any errors if you find them!

Niels

Tom P · Post by **Tom P** » Thu Mar 17, 2005 7:39 am

Nicely done spreadsheet! It's always interesting to see what can be accomplished with Excel.

wooglin · Post by **wooglin** » Thu Mar 17, 2005 7:44 am

Wow. Nicely done.

Krispy · Post by **Krispy** » Fri Mar 18, 2005 5:55 am

Thanks very much

I no longer have any excuses for putting off that job!

ultraboy · Post by **ultraboy** » Fri Mar 18, 2005 6:19 am

niels007,

Excellent tool !! Life is much easier now.

This should go sticky somewhere.

Tzupy · Post by **Tzupy** » Sun Mar 20, 2005 3:22 pm

Speaking of complex fan adapters, how much airflow is lost?
I have a very complex adapter idea: from a 120 mm fan to two 120x20 mm targets, sucking air from two shrouded GPU heatsinks (SLI) to a case side vent.

niels007 · Post by **niels007** » Mon Mar 21, 2005 4:20 am

I once tested various fan adapter lengths in both sucking and blowing

direction.

http://finance.groups.yahoo.com/group/S ... ssage/5507

How much airflow is lost probably depends on a few things. The differencfe of 'fan area' (120mm) and 'target area' (40x120 in your case, 90x55 in my case), length of the tunnel which changes the angles of the 4 sides, and the impendance of the heatsink you're aiming at..

I don't see a problem in your case though as I get great results going from 120x120 to 90x55 over 9cm, easily keeping an Athlon xp at 2ghz 1.5 volt cool with the fan just over 400rpm.

Edit: In that not easy to read post at Yahoo groups, I also used a very small target of 35x55mm and got the same temps as I got with the 80x60 target, this was with the fan blowing in.

120mm 7v blow: 53(c) 60mm adapter
120mm 7v blow: 53(c) 60mm adapter +5cm 'chimney' to 35x55mm

So that didn't seem to matter measurably!

PS: If you have nothing interesting to do on a sunday, try to put that complex adapter into excel, that'll surely keep you busy

(hmmmm .. should.... be... possible..

)

Tzupy · Post by **Tzupy** » Mon Mar 21, 2005 5:38 am

niels 007, thank you for the answer. Bottom line seems to be that if the duct is properly designed / built, then the airflow loss is not major.
I am going to put some original cooling ideas (designs with drawings) on a site, but right now I'm waiting for a couple of workers to finish my chipset heatsink prototype, it's incredible how lazy they are