Zortrax radial fan duct

After using dual standard fans for a while i had them running on 100% to get good results with PLA. With this fan duct i managed faster prints with 60% fan and much better results. Ive not got the ability to do any CFD calculations but if anyone has any advice to improve id be grateful

This thing is inspired by
http://www.thingiverse.com/thing:2156253
http://www.thingiverse.com/thing:1246425

im using this fan http://ooznest.co.uk/12V-DC-40mm-Blow-Fan?search=fan

NOTE - you have to chan