RCOUT Oscillation

I upgraded my 5" quad from 6S to 8S and am seeing pretty large oscillations on RCOUT that seems to be causing motors to heat up. I tried reducing EXPO from .55 to .45 per the rec here Motor RCout oscillation - #3 by dkemxr, but didn’t see any improvement.

Log: 8 12-31-1969 4-00-01 PM.bin - Google Drive

Details on my setup

  • Kakute H7 V2 FC
  • Fettec 8S 65A 4-in-1 esc
  • 850g AUW
  • 1950 kv motor
  • 5" 2-blade propes
  • 8S power

Seems to be primarily driven by Pitch Rate, which is much worse than Roll:

Try setting the Pitch PID’s equal to Roll and see if there is improvement. Both probably need more work.
Hover thrust looks to be ~.09 so set these:

The ESC Telemetry Notch is not picking up a significant mode ~56Hz. Try a fixed notch and some other tweaks as follows:

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Thank you Dave. Your suggestions definitely improved the situation. Working on adjusting PIDs further

Good time to try some in-flight tuning starting with Rate Pitch kP. You will probably arrive at a good tune quicker that way.

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When you do a power upgrade like this you must reduce the PIDs, at the very least reduce to 6/8 = 75% of their previous values, but you might need to do a lot more than this. This is a great way of smoking your brand new motors - your D-term will be way too aggressive and the excess energy will be directly heating the motor coils. The tighter your tune the more likely this is to be a significant problem. I recently upgraded my 5" quad from F40 Pro II v4 to v5 and even that tiny change made a huge difference to the PID requirements (I nearly smoked the motors). So what you should do is:

  • Immediately reduce PIDs by 25%
  • Do 5-10s hovers at most - the motors will heat up easily in this time if you have got PIDs that are too hot
  • Keep reducing by 25% until the motors come down cool.
  • Re-run autotune