How Does MultiRotor Work?

When I started with multi rotors I stumbled on a question How do they even fly? Here is how MultiRotor Work. The reason RC quadrocopters and multi rotors are fairly new on the scene is the complex and rather heavy computing/processing power required to accurately control all the propellers to not only move the heli about, but to keep it stable. Multi rotors are inherently unstable. Only when all propellers are spinning at the exact same rate, producing equal amounts of thrust and torque, and experiencing equal amounts of drag is hover equilibrium achieved. Controlling this manually is all but impossible and only because of today’s solid state gyro and accelerometer technology, efficient and fast responding brushless or coreless motors, coupled with small microprocessors to deal with the hundreds (even thousands) of calculations and control commands every second, can these things fly at all.


For those looking for the meat & potatoes of how this all works together to accuratly move and predict/calculate a multirotor aircraft’s position (commonly using the Kalman Filter algorithm), here’s a very is a good article on it.

When consumer available RC quadrocopters were first introduced a few years ago, they were not that performance minded as the emphasis was on easy going and super stable flight. Times have changed however and many are capable of performing some fairly aggressive aerobatic flight now. In fact, most decent quality hobby grade quads are aerobatic these days capable of performing heart pounding fast flips and rolls, yet can be put into easy stable flying mode/s as well for beginners. In these “easy” modes, the electronics onboard simply won’t let the aircraft pitch or roll past a certain degree so they behave very similar to a super stable micro coaxial RC helicopter.

The latest and greatest generation of mid priced to high end quad rotors are now sporting GPS positioning and an array of other sensors. This gives them even more fully autonomous hands off flight control, way point assigned flight paths, and “return to home” capabilities if the radio link is lost. The level of electronic sophistication required to keep these things airborne is remarkable. They are in effect “aerial robots” since in actuality you are not flying them like a conventional RC helicopter or airplane. You are basically just telling them what to do and the electronics and programming are 100% responsible for the actual flying.

What is the difference between a MultiCopter and a UAV/Drone?

A multicopter becomes a UAV or Drone when it is capable of autonomous flight.  Normally this means taking the accelerometer and gyro information and combining it with barometer and GPS data so the flight controller understands not only it’s orientation but also it’s position.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *