Plane: quadplane: add allow_weathervane transtion class method

ArduPlane/quadplane.cpp

@@ -3259,6 +3259,7 @@ float QuadPlane::get_weathervane_yaw_rate_cds(void)
       position control.
     */
     if (!in_vtol_mode() ||
+        !transition->allow_weathervane() ||
         !motors->armed() || (motors->get_desired_spool_state() != AP_Motors::DesiredSpoolState::THROTTLE_UNLIMITED) ||
         plane.control_mode == &plane.mode_qstabilize ||
 #if QAUTOTUNE_ENABLED

ArduPlane/tailsitter.cpp

@@ -960,4 +960,10 @@ MAV_VTOL_STATE Tailsitter_Transition::get_mav_vtol_state() const
     return MAV_VTOL_STATE_UNDEFINED;
 }
 
+// only allow to weathervane once transition is complete and desired pitch has been reached
+bool Tailsitter_Transition::allow_weathervane()
+{
+    return !tailsitter.in_vtol_transition() && (vtol_limit_start_ms == 0);
+}
+
 #endif  // HAL_QUADPLANE_ENABLED

ArduPlane/tailsitter.h

@@ -163,6 +163,8 @@ public:
 
     bool set_VTOL_roll_pitch_limit(int32_t& nav_roll_cd, int32_t& nav_pitch_cd) override;
 
+    bool allow_weathervane() override;
+
 private:
 
     enum {

ArduPlane/transition.h

@@ -52,6 +52,8 @@ public:
 
     virtual bool set_VTOL_roll_pitch_limit(int32_t& nav_roll_cd, int32_t& nav_pitch_cd) { return false; }
 
+    virtual bool allow_weathervane() { return true; }
+
 protected:
 
     // refences for convenience