Quad motor tail sitter 4.1 yaw response

Hello there. I have been working on a quad tail sitter plane and have had a successful test flight on 4.0.5 which revealed a lack of pitch authority Quad tail sitter first test flight - YouTube . I was advised to update to 4.1 in order to get copter controller in fixed wing flight thus gaining some differential pitch control.

Upon updating, I have lost all yaw control in qstabilize. I have tried several options including updating to 4.1.1 and resetting all parameters and starting from scratch but to no avail.

I noticed that whether I use frame class 0, 15 or 16 there is no response from the motors when deflecting the rudder stick. Roll and pitch respond as expected and the plane will hover but spins round and round. I have tried with control surfaces enabled but that just seems to give even stranger results.

Rolling back to 4.0.5 fixes the issue for me but without the differential pitch that Iā€™d like to try in fixed wing flight.

Please will you help me to understand this statement from the documentation as it seems to me that 4.0 does use torque to control yaw:

in firmware versions previous to 4.1, CopterMotor Tailsitters did not use any yaw torque control. Roll (with respect to plane body) is only controlled by the flying surface (ailerons or elevons). Now QUAD PLUS and X frames have yaw control via motors, and frame types 16 and 17 are added that have no torque yaw control, as previous versions of PLUS and X did.

Thanks in advance

Can you share your param set.

4.1.1_backup.param (20.0 KB)

Here it is

I suggest to increase Q_A_ACCEL_Y_MAX to 110000.

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