DesPitch Drift to -50 and Oscillations

I’ve had issues flying my tricopter running 3.2.1, all seemingly related to the pitch. I’ve attached two logs, the short one from 7/3 I took off, and after a 100 yard down and back, I put it in a hover mostly in place. The tricopter started to oscillate in pitch, then flipped and crashed. It wasn’t really oscillation, just a quick drop in pitch, then back, a pause, then another one, almost like half of a sine wave…

The larger log was a normal flight around a small field, but in the end I had to hold the stick all the way forward to keep it level… it was pitching backward if I let go of the stick. I landed it and replaced the motor, as I thought it might be dragging, but this did not make any difference.

Is there any way to tell if the IMU is actually working or if its a hardware issue? Or is there a way to tell if its PIDs? I haven’t checked vibration, but I balance my props and I haven’t noticed anything obvious.


I just tried another flight, with x,y,z acceleration logging enabled. I still had the pitch osculations, and I took a video of it. It’s subtle, but clearly oscillating in pitch, as I just try to keep the copter stationary.


Here’s the graph that shows the strange DesPitch vs Pitch.