140mm fans like the Noctua work fine on S5's with this adapter:

http://www.amazon.com/Bgears-Cooling-Fan-Adapter-140mm-Black/dp/B0043GMY1U

The only minor issue is that it extends below the base a bit so you'll need to compensate for that with a base plate under the miner (or hang the fan over the edge of whatever it's on).