How to fix propwash in Betaflight
Propwash — the shaking in fast descents and hard turns — is one of the most common tuning frustrations. It's usually not a single value but the interplay of filter delay and damping.
What propwash is and when it happens
Propwash happens when the quad flies through its own turbulent prop wake — typically in descents and direction changes. In the log it shows up as low-frequency oscillation (~15–40 Hz) during descents.
Check filter delay first
Overly aggressive lowpass filtering adds phase lag and is one of the most common propwash causes. Use the RPM filter for clean motor-noise removal so you can raise the gyro/D-term lowpass cutoffs (less delay).
D and feedforward
Enough D damps the propwash oscillation, while too much makes it worse again through noise. Feedforward helps the quad follow rapid stick moves without error building up. Change in small steps and verify in the log.
Verify with a log
After each change, fly a few descents and check whether the oscillation on the way down decreases. PIDoctor detects propwash from the step response and spectrum and shows whether your change helped.