Drones have the ability to self-stabilize and correct for any imbalances, so in an ideal scenario, your quad should be perfectly leveled when up in the air. This means that the pilot doesn’t have to worry about correcting the direction and they can focus on other flying elements such as adjusting the altitude, changing directions, or even performing stunts. In fact, due to this feature, modern quads are very easy to fly, which is why they are so wildly popular all over the world.
Still, unless you have an expensive model that comes with a GPS module that helps it stabilize the position while hovering, some drifting may occur. This may happen because of wind or other environmental factors, but it can also have some internal causes.
If the drifting occurs and is not contained (the quad constantly pulls towards one direction), the pilot is forced to focus on compensating the direction by constantly adjusting the controls. This becomes very frustrating in time and it may even affect the overall flight quality of the quad.
So, if your drone is currently adrift, we listed the things that could go wrong and should be checked:
Check the Gyroscope Calibration
Drifting tends to happen if the gyroscope is not calibrated correctly (mostly with DIY quad kits but can be found in RTF designs as well). To understand why the gyro calibration is important, you need to know how the quad gets up in the air and maintains position.
When the quad gets lift-off, it uses thrust generated by each of the four motors, but the gyroscope is the one to stabilize it to the level position (where the quad is parallel to the ground in a horizontal plane). The gyroscope measures the tilt of the drone every few milliseconds and corrects any drifting by increasing the thrust on the respective motors. This means that, if your multirotor is drifting towards left, the gyro will increase thrust on the two left motors. The action pushes the left side upwards, thus bringing the quad to a level. So, what you perceive as being a perfectly leveled drone, is the gyro hard at work.
But if the gyro is not well-calibrated, the quad may think that level is actually in a tilted position. Keep in mind that, if the gyro is off by 1 degree, the quad will drift, so it’s crucial that you check the calibration!
To fix a drift that’s caused by calibration problems, connect the drone to a computer that runs the flight controller software required for fine-tuning (BetaFlight, CleanFlight, or others). Also, place the quad on a completely flat surface – this will teach it where the level is. Once connected, find the calibration section and press the button that lets you calibrate the gyroscope. Next, follow the instructions on the screen until the software lets you know the calibration action is complete.
Check the Middle Channel Positions
Again, you’ll need to check with the flight controller’s software for this one. Find the section where channels can be fine-tuned and make sure the middle channel position is set at 1500 for all.
The middle channel position is the way to tell your quad that you want it to hover in place and not go anywhere. So, if the position is not well-calibrated at 1500, the quad will drift in one direction or another. For instance, if the position is set at 1510 or even 1505, the flight controller will interpret it as if you want the drone to move in one direction instead of hovering in place.
If, for one reason or another, you can’t set all the channels at 1500, make sure that roll, pitch, and yaw are (these are the ones you need the most). For this, use the Subtrim feature on your radio and follow the indications on the computer screen.
Also, if the quad started drifting out of nowhere, check to see if you haven’t accidentally moved the trims while flying it. This happens quite often, and it can be confusing if you don’t know to check the numbers.
Quick note: some cheaper radios will make it very difficult to get to 1500, so it’s OK to let it at 1501. Just make sure it’s as close to 1500 as possible.
Respect the Initialization Period
Most multirotors need a few seconds up to one minute to initialize and orientate in space after powering on. So, once you put the battery in and power it up, let is stay on a flat surface for a bit. Otherwise, if you move it around, it may not fly all that well.
Check the Center of Gravity
Luckily, you don’t need software or other devices for this! The center of gravity is settled by the heaviest element of the drone, which is the battery. So, if you strap it too far back or towards the front, the center of gravity will not be in the middle of the quad (where it should be).
Check for Damages
If your quad used to fly well and the drift is quite recent, make sure to first check all the steps mentioned above. If everything seems correctly calibrated and set, then have a look at the propellers, motors, and ESC.
If one of the motors is not spinning at the same speed as the others, it can cause the quad to drift. Also, if a propeller is damaged, it can cause extra vibrations, which again, can lead to a significant drift in one direction.
Finally, if the motors, the ESCs, and the propellers turn out to be OK, the next culprit on the list is the flight controller. So, do some trial and error tests and check/replace these elements in the order they are most likely to get damaged:
- Flight Controller
These are the main (fixable) reasons why a quad may drift, so if the drift persists after going through all the checks, you should consider sending it back to the manufacturer for a checkup. If this is not possible (warranty is expired or it’s a kit design), you may have to spend some time to identify the malfunctioning piece.