Hi all,
Looking for some help interpreting a PX4 log from a crash and confirming a desync hypothesis.
Setup: Mark2-7", Holybro Kakute H7 (PX4 v1.18.0), SpeedyBee BLS 60A 4-in-1 ESC, T-Motor 2207 2080KV, 5" tri-blade props, 6S 2600mAh.
Pilot saw smoke in the air right before losing control. Post-flight, all 4 motors have some charred/carbonized winding insulation — one much worse, none in a hard short.
Theory: repeated desync leading to current spikes and insulation damage.
From the log, pointing to desync:
- Roll rate self-oscillating ±240°/s while setpoint stayed flat.
- Gyro PSD shows a narrow, stable 18-20Hz band , in distinct bursts, which vanishes completely in prop-off bench tests.
- Final ~4-5s: one motor pinned at max DShot continuously, two others collapse to idle,
torque_setpoint_achievednever recovers. - Battery sagged to ~19V (3.17V/cell) under load, current peaks ~123A (~47C on 2600mAh).
So my open question is: Does a narrow stable band fit a desync or is it a mechanical resonance?
Thanks!
