QX90 Ducted Frame

Same as the MaxiWhoop frame provided by sepion; but I've chopped the base of the motor holders off, because:
* I can slide the motors in from the bottom
* I can secure and protect the bottom of the motors with heatshrink tubing.
* Easier to print - pulling the supports out of the motor mounts before was pretty impossible.
* I can sit the motors at a custom height (to pull props further into the duct if desired)

Supports required, but easily accessible to remove.
Secure the flight control