The QuadPlane transition is where the aircraft transitions between being primarily a vertical take-off and landing vehicle (VTOL) flight and being a traditional fixed-wing aircraft flight. The transition takes place in two directions, either by the pilot or by switching between airspeed and flight mode.
The main method to start the transition is to change the flight mode, either using the flight mode channel on the remote control or using the ground station command mode to change.
If you switch to manual, the rotor motor will stop immediately.
If you switch to any other fixed-wing mode, the rotor motor will continue to provide lift and stability until you reach the ARSPD_FBW_MIN airspeed (if no airspeed sensor is available, the airspeed estimate). Once airspeed is reached, the rotor motor will slowly descent within Q_TRANSITION_MS milliseconds (default is 5000, so 5 seconds) and after that closes
If you switch from fixed wing mode to QuadPlane mode, the forward motor will stop immediately, but the control plane will continue to provide stability while the aircraft is decelerating. This allows switching to QuadPlane mode at high speeds.
If the Q_VFWD_GAIN parameter is set to a non-zero value, there is an exception to the positive motor stop in QuadPlane VTOL mode. In this case, the forward motor will be used to maintain the height of the aircraft in the wind. See the description of Q_VFWD_GAIN.