We already know that the propellers are what give our drone lift, but how exactly do they do that?

What's interesting about propeller/wing aerodynamics is that there are still a lot of questions about it. Bernoulli's Principle is the general rule that everyone agrees on.

The Bernoulli Principle says that the speed of air and the pressure of air are related in a way that goes against each other. When the speed of air goes up, the air pressure goes down. When the speed of air goes down, the air pressure goes up.

Then, what does this rule have to do with our propellers?

Like the wings on an airplane, the tops of propeller blades are curved and the bottoms are flat. This shape is called a "airfoil" which causes air to move more quickly over the top than under the bottom.

Because of this, there is less air pressure on top of the propeller blades. This difference in pressure creates a kind of suction that gives the propeller a lift force.

Therefore, the blades of a quadcopter's propeller can be thought of as spinning wings. This is different from an airplane, which must fly fast enough to move enough air over its fixed wings to give it lift.