One of the most important parts of your drone are the propellers. These spinning blades are the wings to your craft, the very part that creates the airflow that lifts your machine into the air. Drone propellers come in many different shapes and sizes – they all serve the same overall purpose, but the flight characteristics of each can be dramatically different.
We are excited to get a little geeky about flight today, and will be talking mostly theoretically, you’ve been warned.
Science of Flight series
We have plenty more to read if you are interested in the science of drone flight. We are not physicists, but we know just enough to explain some of the basic concepts of how drones operate, how they fly and how to do so effectively. Be sure to check out our other Science of Flight articles to learn more.
As we explore the different angles of attack, pitch, blade count and more of drone propellers, don’t get too caught up on the technical specifics. We’re going to cover some of the details, but we are not physicists, most of our descriptions are going to be down and dirty.
A propeller is a wing
Are you vaguely familiar with how an airplane wing works? Airflow across the wing creates areas of high and low pressure, resulting in lift. Look up Bernoulli’s Principle if you’d like to know more on that specifically. Simply put, higher speed air travels over top of the wing, creating low air pressure, the opposite happens underneath the wing , effectively pushing things upward.
The propeller on your drone is a wing, actually, in the physics sense of things, it is multiple wings attached together. Spinning the little wings around in a circle creates the same air pressures, thus causing lift.
If you don’t want to follow along the ‘air pressure and lift’ approach to this all, know that the angle of the propellers drives air downward. There is enough resistance in normal air that this drives the propeller upward. That’s right, all of the weight of your drone is ‘held up’ by those small spinning blades, but we’ll worry about that later.
Are we good with this concept – your drone propeller is made up of multiple wings? Good.
The basic concept of a fixed blade propeller is that the faster the motor runs, the faster your propeller spins and more lift is created. Basically, more power = more speed. There will be a theoretical maximum to this, eventually a propeller will spin faster than it can efficiently move air, but for the most part we won’t hit that with our consumer drones. Altitude plays a part in this as well, read up on air density to see what I mean.
All of us DJI Mavic Pro owners should be familiar with a small number on our remote controls, a live readout of the RPM of our motors. With a stock set of folding Mavic Pro propellers, my machine rotates at about 6000rpm to hover. I usually fly between 300 and 1200 ft above see level at take-off. Your hover speed will change at different elevations, and in different temperatures and humidity levels, but that may be beyond our scope today.