Flsun Fan Duct - 270 degrees.

thingiverse

Update Apr 21: The FLSun i3 hotend wasn't aligned properly, so I moved the fan connection a few mm to the left. At the same time, I widened the airway from the fan to the circular part by adding internal flow directors for better airflow balance. A warning: The fan end requires additional support, but be careful not to generate supports around the duct outputs or you'll struggle removing them after printing. I used a 2mm drill bit to clear the output holes since I forgot to do so earlier. I was experiencing overhang issues with the side facing away from the 1/2 round duct, so I upgraded it to a 3/4 round and achieved much better results.