Quick Answer
Blackbox logging records detailed flight data, including gyro readings, motor output and stick input, so you can review exactly what your drone did during a flight. You can record this data to onboard flash or an SD card, then review it in free tools like Blackbox Explorer or PID Toolbox to spot tuning problems that are hard to feel or see in the air.
What Blackbox Actually Records
Blackbox logging captures a detailed timeline of your flight, sampled many times per second. The main data points include:
- Gyro data, showing actual rotation on each axis
- Setpoint, showing what your stick inputs were asking for
- Motor output, showing the power sent to each motor
- RC command data, showing your raw stick and switch positions
- Battery voltage, tracked throughout the flight
Compare setpoint against actual gyro movement. You will see exactly how closely your drone followed your commands. You will also see where it lagged, overshot or wobbled. This is far more precise than judging a tune by feel alone.
Onboard Flash vs SD Card
Flight controllers record blackbox data in one of two ways.
Onboard flash is a memory chip built into the board. It is easy to use, since there is nothing extra to plug in. Its storage space is small, though. You may need to download and clear logs often. Not every board has onboard flash. Check the specs first. Our flight controller buying guide covers this too.
SD card logging uses a microSD card slot on the board. It usually holds far more data than onboard flash. This helps if you fly many long sessions between log reviews. You are less likely to run out of space mid-flight.
Either method works well. The right choice depends on what your board supports, and how often you plan to check your logs.
Setting the Logging Rate
Betaflight lets you pick how often blackbox records data. Lower rates save space. Higher rates capture more detail. A higher rate gives a sharper picture of fast events, like a quick wobble. It also fills up storage faster.
For most tuning work, a moderate to high rate gives enough detail. It will not fill onboard flash too fast. If you are chasing one fast problem, like motor desync, use a higher rate for a short test flight. This helps you catch it clearly.
Getting Your Logs Off the Board
After a flight, connect your board to the Betaflight Configurator. Open the Blackbox tab. From there, download the log file to your computer. If you used an SD card, you can also remove the card and copy the files directly. This is often faster for large files.
Download and clear your logs often if you use onboard flash. It can fill up and stop recording new data. This can happen without a clear warning during a flight.
Reading Logs in Blackbox Explorer
Blackbox Explorer is a free tool. It opens a log file and shows graphs of your flight data over time. The most useful view for tuning shows setpoint and actual gyro movement on the same graph, for each axis.
What to look for:
- Close tracking between setpoint and gyro movement usually means a solid tune on that axis.
- Overshoot, where the gyro line goes past the setpoint before settling. This can mean your D-term needs adjusting.
- A repeating wobble, which often points to a filter or PID value that needs attention.
- Motor output near the max limit on one motor. This can point to a mechanical or balance issue rather than a tuning problem. It is also a common cause of hot motors, covered in our hot motors troubleshooting guide.
Using PID Toolbox
PID Toolbox is another popular tool. Pilots often use it alongside Blackbox Explorer, or instead of it. It focuses on frequency data. It shows noise at different frequencies, rather than a simple graph over time.
This view is great for spotting vibration problems. Noise at one specific frequency often points to a mechanical cause. This could be a bent prop, a loose motor, or a frame that vibrates at that frequency. It is rarely a pure PID setting problem. Chasing a noise spike with filter changes alone rarely fixes a mechanical cause.
What to Look For, Step by Step
- Open your log in Blackbox Explorer and check overall setpoint tracking on roll, pitch and yaw.
- Note any obvious overshoot or oscillation on a specific axis.
- Open the same log, or a similar one, in PID Toolbox and check for sharp noise spikes at specific frequencies.
- Cross-check any suspicious axis against your gyro chip and filter settings, since some gyro chips need different default filtering.
- Make one change at a time, test again, and compare the new log against the old one.
Why Logs Beat Guessing
Flying by feel alone can lead you to chase the wrong setting. Small tuning issues are often hard to notice in the air, especially at speed. Blackbox data turns a vague feeling into a clear picture. This makes each tuning change more likely to actually help. If you are new to Betaflight setup, start with our Betaflight setup guide before you dive into log analysis.