A part fan mount for a RigidBot single extruder (might work on a double). I like it because it keeps the fan out of the way.
The bracket leaves just enough room to hit the tension lever with a screwdriver and it screws down using the two screws for the bearing.
It's designed to be used with this fan: https://www.amazon.com/dp/B00H8VV0XK/ref=cm_sw_su_dp
but others may work.
The duct works well and doesn't blow on the hot end enough to matter. It snaps into place but I don't trust it so I used tape just to be sure.
Finally, the fan mount poles have a hole in them near the end for a pin or a bar to hold the fan on. I used a rubber band and it works fine.

Update 10/2016: Fixed the scaling issues. Should work without any scaling now.

Printed in PLA at 80 mm/s .2mm layer height.
The mount should print fine as-is but the duct does well with support touching buildplate in Cura.

Works with Simplify 3d.