What if they all spun the same way?

What if all four spun clockwise?

Imagine all four propellers spinning clockwise, seen from above. When a motor turns its propeller clockwise, the motor and the body it sits on get twisted counterclockwise. With all four twisting the same way, the body starts to spin counterclockwise. After 3 seconds it is spinning about 2 times a second.

Why?Sit on a spinning office chair and turn a heavy wheel one way with your hands. The chair turns the other way. A propeller has to keep shoving through the air, so the motor keeps working, and the body gets twisted back by the same amount. The white rings show which way each propeller spins. The colored arrows show which way the body gets twisted.

Go furtherThis scene is a what-if calculation, not a real drone (shown 2× slower). A helicopter has one big rotor that makes this twist, and its tail rotor pushes sideways to cancel it. A force that tries to turn something is called torque.