Chapter 1. What is a Multicopter?

In the simplest terms, a multicopter uses multiple propellers (rather than a single rotor blade such as on a traditional helicopter) to provide lift. Also, there is no tail rotor (used to provide yaw control and counter the torque put out by driving the main rotor on a helicopter). Multicopters come in many configurations. There are bicopters (two rotors such as on CH-46 helicopters), tricopters, quadrocopters, and so on. In the following image, you can see an example of a quadrocopter as well as two configurations of hexacopters (six rotors):

Let's also think of what a multicopter isn't. We've all heard that dreaded term … drones. A multicopter isn't really a drone in the true sense. Rather, it's defined by the U.S.'s Federal Aviation Administration as an Unmanned Aerial System (UAS). The term UAS covers a wide array of aircraft, from drones to your average hobby radio-controlled airplanes. Most multicopters are piloted in the line of sight (LOS), just as any radio-controlled airplane. This variety is not considered a drone. Technically, a drone both flies outside LOS and has the capability of autonomous flight (autopilot).

With specialized equipment, you can fly a multicopter using a first person view (FPV) camera system, telemetry, and so on, and turn your multicopter into a fully autonomous drone. Therefore, some drones are multicopters, but not every multicopter is a drone.

Most multicopter pilots, however, shy away from the term drone. This is because the term drone evokes images of aerial assassinations using missiles and guns mounted on the aircraft. For instance, in a 2013 article in the Santa Rosa Press Democrat about multicopters, a Santa Rosa police officer was quoted as mentioning "fly-by gang shootings" as crimes just around the corner. Once you know how a multicopter flies, the idea of mounting a weapon system onto a multicopter is physically laughable and ludicrous. Mounting a firearm to a drone provides such a counterforce (kick) that the mental image of the result conjures Wile E. Coyote chasing the Road Runner. The multicopter flying backwards as the bullet stays in one place. Comical indeed!

A multicopter's primary function is for videography, cinematography, and photography. So, what's the difference between a multicopter and a drone? The answer is the guidance system and how you choose to use it.

Still confused? Don't worry, that's what this book is for. Let's dive right in …