I made a new fan duct for my prusa mendel i3 Rework and I was thinking why not share it with others!
My original duct was not concentrating the air on all the sides of the hot end so I created a new one which does this way better.
I also added the solidworks part for you to customize it in every way you like, but give me a message if you created something nice.
It can be printed without support!
EDIT: It's for a 40x40mm fan :)
I just printed the part with a 0.3mm layer height and a speed of 20mm/s.