Can You Make a Drone with an Arduino Uno as an FC?

Hi, 

theoretically, it's possible, but it's very cumbersome because you have to connect and set up all the sensors manually. The Arduino Uno also has very little memory and very limited processing power. Real-time PID loops with sensor analysis, compensation, and attitude determination are at their limits. There's no multithreading! Everything on the loop has to be precisely timed manually. The result is that everything is incredibly sluggish, and you can't fly with it. It's a good project for learning in theory, but unsuitable for practical use.
Good luck!