A NACA duct intake for foam planes. The cutout needs to be 2.5 inches wide and 3 inches long and have 0.2 inches gap around it for the lip. It has a pretty big opening and 2 of them are enough to cover a 40mm EDFs intake area. They would also be good for cooling an esc with a heat sink or a DJI...
This is the print file for the custom EDF motor-mount-ducts that I designed for my 7ft B-52.
It has been updated to work with 2" props, and has motor mount holes for the 1106 size motors.