After a short brake, let's return to Blackbox series with new entry: "How much gyro noise is too much?".

Almost all PID tuning tutorials states: reduce vibrations that affects gyroscope and accelerometer readouts. Yes, this true: any vibrations that appear during flight affects gyroscope and accelerometer readouts are bad and should be kept as low as possible. This can be done by balancing motors, propellers, using stiffer frame, adding dampeners, lowering LPF filters. But how much vibration induced gyro noise is too much? Let me answer with four Blackbox screenshots:

Super smooth gyro traces, no noise

smooth gyro traces

This is how it should looks like! Perfect trace. If it is archived without lowered LPF filters, then kudos for balancing everything!

Somehow noisy gyro traces

somehow noisy gyro traces

Little noise appears, but amplitude is low, everything is under control.

Noisy gyro traces

reasonably noisy gyro traces

Gyro noise is visible. It is not a problem yet. If it was a result of raised LPF cutoff frequency, extra noise might be worth lowered signal delay. I would start to think how to reduce it on a hardware level. Perhaps bearings are dying, or propellers should be rebalanced?

Extremely noisy gyro traces

extremely noisy gyro traces

This is how unflyable gyro noise level looks like! If you see have problems with flight performance, you know what is causing it. This have to be fixed ASAP before everything else.