This is the fan module add on for the Brabeast http://www.thingiverse.com/thing:48087 which is based upon the famous walking Strandbeest from Theo Jansen ( http://www.strandbeest.com ). It is modular clip together system that is 3D printer (FDM) friendly just like the original Brabeast. The fan has a sun gear driving some planetary gears, there is a split annulus (always makes me snigger) gear which achieves a very high reduction (86.4:1) A video of this : http://youtu.be/PdvfL4GfMk0 http://youtu.be/vUjEQ_0bEqg http://www.gyrobot.co.uk http://www.facebook.com/gyrobotuk Printing instructions : 1 x PLATE_PLANETARY_FAN_MODULE.stl Full Bill of Materials incase you want to print seperately (separate stls included):1 x CRANK SHAFT FAN ADAPTER (BLOOD RED) 1 x BIG FAN SUN GEAR (BURGUNDY) 1 x ANNULAR GEAR (PURPLE) 1 x DRIVING GEAR (BLUE) 2 x PLANET CARRIER (LIGHT BROWN) 3 x PLANET GEAR (DARK BROWN) 4 x PIN (GREY)Assembly Instructions:Please assemble according to BRABEAST FAN MODULE.stl (view in Thingiview).Note: The original Brabeast CRANK SHAFT ADAPTOR will need to be replaced by the one in this pack to enable the fan to be mounted.Disclaimer : Coupled with the original Brabeast this is quite an advanced build with lots of moving parts (meshing gears, cranks etc). Depending on your printer calibration, this may or may not work at first, there is a running in phase where the mechanism may be tight at first but should loosen up over time. Good luck and enjoy building this model.