The rim half will be 3D printed, it's also a nice test how tough the prints will be. The frame is made of aluminium rods. I'm using a 250W electrical bicycle motor I got cheap on ebay.
The Motor will be mounted to the aluminium frame with some rood. I cut a thread in the center and and some counter screws sideways.
I also drilled holes in the motor and mounted screws sideways to mount the 3d printed rim parts. With the basic frame completed it starts looking like something to drive with: