Plane: added in FF component in tailsitters

this is needed for decent control of tailsitters

ArduPlane/tailsitter.cpp

@@ -164,9 +164,9 @@ void QuadPlane::tailsitter_output(void)
     plane.rollController.reset_I();
 
     // pull in copter control outputs
-    SRV_Channels::set_output_scaled(SRV_Channel::k_aileron, (motors->get_yaw())*-SERVO_MAX);
-    SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, (motors->get_pitch())*SERVO_MAX);
-    SRV_Channels::set_output_scaled(SRV_Channel::k_rudder, (motors->get_roll())*SERVO_MAX);
+    SRV_Channels::set_output_scaled(SRV_Channel::k_aileron, (motors->get_yaw()+motors->get_yaw_ff())*-SERVO_MAX);
+    SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, (motors->get_pitch()+motors->get_pitch_ff())*SERVO_MAX);
+    SRV_Channels::set_output_scaled(SRV_Channel::k_rudder, (motors->get_roll()+motors->get_roll_ff())*SERVO_MAX);
 
     if (hal.util->get_soft_armed()) {
         SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, motors->thrust_to_actuator(motors->get_throttle()) * 100);