Designing Purpose-Built Drones for Ardupilot Pixhawk 2.1

Even numbers

There is an exception, namely tricopters (three rotors). Although these were fairly common about 5 years ago, they are notoriously unstable. Why? Because of how multicopters turn. More blades not only equal better stability and lift for a multicopter, even numbers make the calculations necessary for Pixhawk to keep it in the air easier. If you remember, back in Chapter 1, Drones 101, we covered the physics of how a multicopter's yaw works. Even numbers make this far more stable.

In conjunction with symmetry, let's lay out how many degrees the different blade configurations would be in the following table. Just imagine looking at the multicopter from before and dividing the sections like slicing a pie. If there are 360 degrees ...