In the previous project The Ball-Drone Project I was faced with the challenge of building a slightly different drone. Now I don't really come from the field of flight dynamics and still had to learn a lot. In principle, the first ball drone flew. Correct maneuvering was nevertheless not possible, however, as the drone tended to "tip over". I was unable to get the problem under control by making adjustments to the flight controls. I found a very good video Drone Pendulum Fallacy by Tom Stanton that shows the subject of center of gravity of drones clearly. The leverage of the wings in relation to the center of gravity was insufficient to safely control the drone. So I threw the whole concept overboard and tried again.
Some good information about single-rotor drones: ArduPilot