I designed this crazy cart fan because I use a 36v battery with a 24v motor which does make the cart go faster but it comes at the expense of added heat to the motor. So, enter the Crazy cart fan the fan simply fits over the nut that holds the upper sprocket in place. This has many benefits including that it doesn't draw much more energy than just running the motor without a fan and doesn't affect top speed. I did have to move the ESC a bit lower and take the motor covers off but that is a small price to pay for all the benefits. The fan also makes interesting sounds at high speeds. I would print this fan in either pla pro/pla + but this would benefit from using a stronger material that still has a bit of flex in it such as petg or anything strong. You can use any layer height but, the smaller the layers the higher quality it is, I haven't seen any difference in performance when using different layer heights. It will also require supports. To attach the fan I used a bit of super  glue and just stuck it over the the nut that holds on the upper sprocket. You do need to make sure that you attach the fan straight on to the nut or else it will wobble a bit but this won't have very much of a an effect on the actual performance it just may come loose sooner.