This is my second spinning top. It isn't as polished as my first top but I've integrated basic aerodynamics to see if it will improve spin-time.
This is a clockwise spinning top. Although, it will spin counter-clockwise but the aerodynamics effects will be void.
This top uses the same 3/8" nuts and 1/4" ball bearing as my previous top. The purpose of the holes under the nuts was to be able to remove them easily for re-purposing purposes, but due to the ducted design of this top, I removed the bottom holes to prevent airflow from coming back up through the nuts and disturbing the flow. So a 3/8" screw will be required for extraction on this part.
This part is not perfect. There are some parts that didn't print perfectly using a 0.4mm nozzle so a 0.3mm or 0.2mmm nozzle is recommended.
I've printed mine at 0.4mm x 0.2mm thickness. 3 shells and 20% infill. My nuts may not be balanced so I got a little wobble.
In case anyone is wondering, this model is in millimeters, so scale accordingly.
Don't expect the aerodynamics to be mind-blowing. However, you can feel an extra breeze coming from the bottom of the top. Perhaps I'll add a mini jet engine in the next design.