I redesign this blower duct http://www.thingiverse.com/thing:560790 in order to fit into my flashforge creator pro.
I used this blower duct with a SUNON GB1205PHV1-8AY.GN (http://fr.farnell.com/sunon/gb1205phv1-8ay-gn/turbine-50x50x15mm-12vdc/dp/1568490).
Don't forget to print the blower wedge otherwise your blower will touch the frame of your printer at the home position.
I also made some modifications into my MakerWare configuration files :
blower.stl | 89.3KB | |
blower_wedge.stl | 3.0KB |