Three versions of circular clip-on fans for the Anycubic i3 Mega with larger fan ducts that don't fit mileshkin's original design.
24 holes - lower airspeed
12 holes - greater airspeed
airblade - sweet looking design that is a challenge to print without getting supports stuck in it
if anyone discovers an easy way of printing the airblade version pls send me a message and let me know.
UPDATE 30-Oct-2018: The improvements have been expanded to the aiblade version, which can now carefully be printed right side up with tender supports under the upper edge of the airblade. Still quite a challenge!
UPDATE 29-Oct-2018: Further improvements were made to airflow and printability. A great "Thank you!" goes out to Trayal and mherwigDE for their great observations and criticism. The part now prints without supports for the ring! Also, airflow is now directed further downwards onto the print, rather than the nozzle. Airflow is also spread across all holes a lot more evenly than before.
I have also encountered problems with the roof of the ring using the newest 3.5.1 version of Cura. For some reason it is trying to start the bridges in mid air, instead of on top of a wall. I got around this by setting the wall line count to "1". This made no real changes to the way this was printed with a 0.4 mm nozzle and placed the bridges in the right place again for proper printing.
UPDATE 07-Sep-2018: All versions have been updated and further improved. Airflow is now more evenly distributed and structures easier to print.