Quadplane Throttle is capped at 50%. Any ideas as to what could be causing this?

ArduPlane VTOL Plane
1

My team is working on an ardupilot based VTOL and we have now made a few attempts at test flying without success. Whenever we raise the throttle it increases nicely initially, but eventually gets clamped at either 50% or 45%. We took off the props, and when we quickly give it max throttle it goes up to 75% before quickly falling back down to 50%. All testing was done in QAcro and QStabilize flight modes. The throttle value is the one read off of telemetry in QGroundControl.

Here are some things we have tried:

  • Replacing the Cube
  • Disabling Throttle Exponent
  • Disabling hover learn
  • Setting THR_MAX to 100%

We have looked through what feels like every parameter related to the throttle, so any help/insight would be greatly appreciated.

Parameter list linked here:

2

What motor, battery and ESC are you using? Could be an ESC-setting or a power-issue.
Also, if you hook up one of the ESC’s to a servo tester, how does the motor perform then?

3

Besides providing the make and model of your motors and ESCs, have you calibrated your ESCs (old school) directly from the received to make sure the end points are recognized and set?

Good luck.