Your drone is flying sideways because there is an imbalance of forces between the 4 sides. Either all the propellers are not producing equal thrusts while hovering or the weight on one side is slightly larger than the other. This can be corrected quite easily using trim settings or by physically removing the cause of imbalance.
Your drone can be flying sideways due to any one of the following reasons:
- Propellers are mounted on the wrong motors.
- Propellers are damaged.
- One or more motors are not producing enough thrust.
- Your drone IMU/compass is not calibrated properly.
- Your remote controll sticks are miscalibrated.
- There is strong electromagnetic interference from nearby source.
- You are flying in a strong wind.
A sideway flying drone is quite common. Especially if you are new to the hobby and have your first experience flying your drone, you might face this. But the good thing is that this problem can be fixed quite easily IF you identify the cause of the unbalanced force.
In this article, I am going to discuss all the probable reasons for a sideway drifting drone and also solutions to rectify the problem.
Reasons for drone flying sideways
Let’s discuss each of the above-mentioned reasons and see how they affect your drone and how can we fix the issue to be able to fly correctly.
1. Wrongly mounted propellers
This is a rookie mistake and is the most probable cause of drones flying sideways. On both the front and back arms of the drone, one motor turns clockwise and the other turns counter-clockwise. This is done to counteract the moment produced by each turning propeller (much like a tail rotor on helis).
Since all propellers have to produce thrust in the same direction while rotating in opposite direction, the propellers are designed specifically for each motor. That’s why you can’t put a counter-clockwise (CCW) propeller on a clockwise (CW) motor and vice versa. If you do this, the propeller will push the air in the wrong direction and result in your drone tilting to one side and flipping over.
DJI drones come with a special locking mechanism that prevents the accidental mounting of propellers on wrong motors. There was a famous lawsuit between Autel and DJI about this patented locking mechanism which was then settled after Autel won the lawsuit. In some DJI drones (like the Mavic Air 2), you will even get a checklist on the FlyApp warning about checking the correct mounting of the propeller before flying.
HOW TO FIX: If your props are mounted on the wrong motors, your drone will either refuse to take off or will soon flip over immediately after taking off. This is a clear sign of wrongly mounted propellers. To fix this issue, follow your drone manual for the correct mounting of each propeller on its corresponding motor. DJI and Autel have proprietary locking mechanisms. Other drone manufacturers use colour marking to indicate which propeller is for which motor.
2. Damaged propellers
Since the side drift or tilt is caused by imbalanced thrust force, your next step should be to inspect your propellers for any possible sign of damage, cracks or broken tips.
A physically damaged propeller will be unable to produce the same amount of thrust compared to the other propellers. This reduced thrust will then result in a sideways drift. In high-end drones, the gyroscope will detect this anomaly and will increase the motor RPM to counter the imbalance but if you are flying a mid-range drone that does not have this sophisticated system, you are in for a ride (albeit sideways).
If you have recently crashed your drone or have hit a pole or wall, your might have a broken propeller tip (especially if you were flying without propeller guards). This is one of the most common damages props endure during flights.
HOW TO FIX: Inspect your drone propellers and if you find a damaged or broken propeller, replace it before flying. Most drones come with a few spare propellers. If yours don’t, you can get spares from the manufacturer quite easily.
3. Malfunctioning motors
Just like a damaged propeller, a malfunctioning motor can also cause one arm of your drone to produce less thrust and hence tilt and drift to that side.
Motor malfunctions are not very uncommon. It can be due to damaged bearing or dirt inside the casing resisting the rotor motion. It can be as simple as a hair strand or cotton thread wrapped around the rotor and blocking the motion.
Whatever the reason is, a blocked motor can put additional load on ESC and cause current overload. This could ultimately damage the motor or the ESC beyond repair.
High-end drones detect the unusual surge in current drawn by the motor from ESC and register a “motor error” in your controller or flying app. This is an early warning for potential damage and should be taken very seriously. If you fly despite the warning and one of the motors end up failing or malfunctioning, the drone will start drifting in one direction. In a worst-case scenario, you could end up crashing your precious drone as well.
HOW TO FIX: It is a good practice to inspect your drone physically before each flight. During such inspections, test your motor, motor mounts and prop area for any sign of damage, dirt, sand, or other foreign objects that could hinder its normal operation. If you find anything, clean it out with a soft brush before taking off. If the bearing is damaged and making noises and vibrations, it’s time to replace your motor and install a new one.
4. Miscalibrated drone IMU & Compass
Another reason for a sideway drifting drone is miscalibrated IMU and compass. All modern drones use a number of sensors to ascertain the position and velocity of the drone during the flight. These sensors include the accelerometer, barometer, gyroscope, thermometer and compass.
Like all sensors, they need a reference point to work properly. For example, the gyroscope needs to know which way is up & down before the drone takes off. To do this, we go through a process called a sensor or IMU calibration.
Each drone manufacturer has its own recommended method of calibrating the IMU and compass and the process is often guided through the fly app or computer interface.
If your drone is not properly calibrated, it can misbehave in a variety of ways including drifting sideways. This should be one of the earliest things you should check before replacing any hardware or opening up your drone.
5. Miscalibrated controller stick
It is quite possible that the problem is not with the drone itself but with your remote controller. Your controller sticks need to be calibrated at the start and usually, they work fine. But if you find your drone drifting sideways, it is a good idea to recalibrate your remote controller sticks using your manufacturer suggested method.
If you own a DJI drone, the calibration can be done easily through your Fly App on your phone. Your remote controller needs to be ON and your drone needs to be OFF for the calibration process. Below is a short tutorial from DJI explaining the process. Other manufacturers will have same or similar process.
6. Magnetic interference
Your drone utilises a number of sensors to keep itself correctly oriented with respect to you. These sensors are quite prone to magnetic interference and if you fly above or near a source that is producing strong electromagnetic waves, it can through your sensors away. This might result in unexpected behaviour including the drone drifting to sides.
The most common cause of such interference is high voltage power transmission lines. Apart from active magnetic fields, large metallic structures like rebar reinforced concrete, fences or any other large metallic structure. They may not produce their own magnetic fields but they distort the earth’s natural magnetic field enough to through your compass off by a few degrees.
Another important thing to keep in mind is; Never calibrate your drone IMU and compass near metallic objects or under the power transmission line. Doing this will set the wrong “zero” point and when you fly away from the distorted magnetic field and into the earth natural magnetic field, your drone will behave irrationally and may possibly get out of control and crash even.
7. You are flying in a strong wind
Last but not least, do not ignore weather conditions while flying. Your drone can resist the winds and correct itself due to sensor feedback loops but if the winds are too strong, it can get carried away. your drone weighs just a few pounds anyway so it’s very easy for strong wind or gust to push it from its course.
Why does my drone fly sideways – Conclusion
We discussed the most probable cause of your drone flying sideways including wrongly mounted propellers (always check this first), miscalibrated drone sensors and remote controller sticks, damaged motors and props and unfavourable weather conditions.
If none of these solutions works for you, perhaps it’s time to reach out to your manufacturer and see if they can have a model/manufacturer specific solution for you. I usually start with a web search about my specific drone model and see if the problem is faced by other drone pilots. If I don’t find anything, I send an inquiry to the manufacturer (usually it’s DJI) and always hear back from them.