Ever wondered how do quadcopters work? The basics are really very simple! In this article we explain the physics of quadcopter flight and the role each of its components play in making it happen.

#### The Thrust and Weight Forces

Each of the rotors (propellers) of a quadcopter drone generates an amount of thrust proportional to the speed at which the respective rotors are rotating. Yes, the design of the propeller also affects the amount of thrust generated, but since we cannot influence that in flight, it is considered separately.

Together, the rotors provide sufficient total thrust (TT) to support the weight when the vehicle is in the hover.

By increasing or decreasing the TT, the vehicle will ascend or descend since weight remains constant (in this demonstrative example).

The quadcopter flight controller can accelerate the RPM of the rotors on one side, causing the vehicle to roll towards the opposite side.

The total thrust vector tilts in as well, and the horizontal component of the vector “drags” the vehicle into that direction.

#### Pitching and Rolling

The same principle applies for whichever direction you want your device to move towards, whether its left, right, forward, backwards or skew. And, as an added bonus, your drone calculates automatically which rotors need speed adjustment, and how much, for any given set of circumstances and required movement.

#### Yawing

There is an interesting catch to all of this, though. If the rotors would all spin in the same direction, the body of the drone would want to react by rotating in the opposite direction.

For this reason, the direction of rotation of the opposite propellers are designed to be opposite as well, so that the rotational moment can be cancelled out.