How To Control a Multirotor Drone
So you’ve been tempted to try your hand at flying a quadcopter or other multi-rotor RC aircraft, and you have no idea where to begin. Well, welcome! I’ll give you a quick rundown of how to get started, so that you’ll be whizzing around in no time and (preferably) not crashing.
I (and just about everyone else) recommend strongly that your first multi-rotor craft should be a sub-$50 nano- or micro-sized drone. The principles and flight control skills are exactly the same as with a full-sized drone, and this a safe and affordable way to both learn and stay sharp.
So before we talk about anything else, let’s get the actual nuts and bolts of controlling your flier over and done with. I’m going to use quadcopters as the main example, but the same applies to all fixed-pitch multirotor craft. For an explanation of the difference between fixed-pitch and collective-pitch RC craft, have a look at my “How Do Multirotors Fly?” article.
Your quadcopter (and any aircraft, really) can perform three basic movements: yaw, pitch and roll.
Yawing simply means turning left and right, rolling means tilting side to side and pitching is, well, pitching the craft up or down. By combining these three movements you can fly your quad in any direction, fly in circles, do turns, and so on.
Have a look at this basic radio transmitter from a nano-quadcopter:
You’ll see there are two sticks, much like you’d find on a video game controller from a Playstation or Xbox. Unlike those controls, however, the left stick is not centered vertically by a spring. It will stay wherever you put it in the vertical axis.
Now, the left stick controls two things: throttle and yaw. When the left stick is all the way down there is no throttle, the rotors won’t turn and, if you are in the air, the whole quadcopter will drop like a brick. If you push the left-hand stick left or right in flight, the quadcopter will yaw left or right.
Push right-hand stick up or down and you’ll pitch the quadcopter forward or backward. This will also have the effect of making it fly in the direction you pitch it.
Using throttle, pitch, yaw, and roll you can make your quadcopter do all sorts of maneuvers. Learning what each does by itself is relatively easy, but mastering what the many mixes of each does to the craft in flight can take a very long time to master, if you ever do.
One very important point is that the control scheme described here is not the only one there is. This is known as the Mode 2 control layout and it is the most popular one. Mode 1, on the other hand, moves the throttle to the right stick, and moves the pitch to the left stick without moving yaw and roll. To me, Mode 2 makes the most sense since one stick controls all the horizontal movement, but you may prefer Mode 1 instead.
Kung Fu Grip
The next thing you need to think about is how to hold your radio transmitter. Surely, you may ask, there is only one correct way to hold the controls? Well, not really. It depends on what you want to do and what feels comfortable to you.
There are basically two ways to hold the transmitter, and many forum flame wars have been started by this discussion. The first is the one most people instinctively adopt, with their thumbs on the sticks and index fingers where the bumpers would be if the transmitter were a gamepad. For advanced camera drones this makes a lot of sense, because if you are a lone pilot that’s where some of the camera controls and mode switches are located.
Another option is the so-called “pinch-grip” where each stick is pinched between the thumb and index finger. Personally, this is what I prefer since it gives me a feeling of precise control, but it works better for transmitters that use the thinner, knurled sticks rather than the gamepad-style thumbsticks.
Your best bet is to try out different things. If using your tongue works best for you, then who am I to argue? But it’s important to find your preference so you can consistently practice using that method.
Trimming Your Sails
If you look at my little nano-drone control again you’ll notice that the right stick has two little switches beside it. On larger drones you’ll also find two more for the left stick. These are called trim switches and there is usually one for every control axis.
These are used to calibrate the inputs from the transmitter to the aircraft. The position of the stick and the actual speed of the relevant rotors may not be properly in sync. So when you first take off from the ground it may be necessary to “trim” these inputs so that false signals are not being sent to the flight controller.
For example, if you are not pushing the right stick forward on a Mode 2 radio, but the craft crawls forward, you would set the trim in the opposite direction until the quadcopter stood still while the stick is centered.
Often a quadcopter needs a slight bit of trim at the start of the flight and perhaps a bit more as the battery nears depletion, but if no amount of trim gets it flying right, it’s likely some sort of malfunction.
Rates of Control
Another thing you need to be aware of are control rates. The actual motors have a 0% to 100% throttle speed, but how that translates into stick movements can usually be changed.
Many quadcopters have “beginner” or “indoor” modes that lower the rate at which the motors speed up and down as well as the maximum speed that they can achieve. This makes it easier to learn, since the quad won’t scream like a bat out of hell straight into the nearest wall when you just nudge the stick.
Some quads also have a “stunt” mode where the quadcopter does an automated flip or roll if you push the pitch or roll controls past a certain point. This is a cool diversion, but gets boring pretty fast. It also needs quite a bit of height to do safely, unless you want to smack the quad straight into the ground at top speed.
Some quads have special flight modes you can select. You should refer to the documentation that came with it for details, but two common ones are an auto-leveling switch and “headless” mode.
By default a quadcopter will level off if you center the pitch or roll control, making use of the built-in gyro. By switching this off it will stay at the attitude you set it to and require manual leveling. This is pretty advanced and you won’t even find the option on many quads, but it can allow you to do some pretty advanced things that are harder with auto-leveling activated.
A headless mode feature removes the issue of orientation from your flying. Usually you have to keep an eye on where the nose of the craft is facing so that you know how your controls will act. If you are hovering nose-in for example, it will feel like the roll and controls are reversed – which they are, relative to you. Because the quad knows where the transmitter is, though, it can be set to move relative to YOU and not where its nose is pointing. So pushing the pitch forward will always move the quad away from you, and likewise for the other controls.
Keep On Keepin’ On
Now you know the basics, and I recommend you have a look at my other article about how to practice flying and get started in a systematic way. You’ll be doing a lot of practice, so doing it efficiently is pretty important. My guide to getting going and practicing well should help on that score.