One of the mistakes beginner (but not only) pilots and drone builders make is that they use too small motors. People think that if a motor works fine with 5-inch props, it will work with 7-inch props as well. It's not true. In this longish video, I will tell you how to choose motors for your drone: 5-inch, 6-inch, and 7-inch. We will talk about torque, power, a moment of inertia, what happens when you put a too big propeller on a motor.