A brushless flywheel cage for the Nerf Stryfe, designed for Hobbyking's 2627-3800kV brushless outrunner motors. I use the Afro 30A Mini speed controllers, running a modified version of Simonk. The code for my Teensy 3.2, which should also work on a Teensy LC, is available on the Github repository.
Spinup time is comparable to 180 motors with stock flywheels, and I haven't chronographed it, but it has an 8mm flywheel gap, and I estimate it's shooting in the 150-160 fps range. You're free to use and modify my design for non-commercial use, and so I have included the Fusion 360 source files. Here's the Nerfhaven thread if you're interested.
Print the cage and flywheels at 90% or 100% infill. All files are oriented as they are meant to be printed, and the cage requires support material. I used Slic3r, and it was important for the flywheels to be printed with seam position set to random, concentric infill and top/bottom fill, and no supports. I would be worried about PLA getting soft under the motor heat, so would advise PET or ABS. A flywheel installation spacer is optional, though helpful for positioning the flywheels at the right place on the motors.