I got my first lesson on how to do the basic aerobatic (Inverted / Victory Roll / Loop) earlier (thank you Michael). While I was practicing the inverted flight, I guessed I put the down elevator too much, it just goes up vertical until it stall. I got panic and accidently turn on the Trainer port which makes my radio lost all connection. :'(
Thank you Robert and Andy - who help me recovered the plane.
Here is the video I recorded earlier.
http://youtu.be/InF3dt8AyOo
Lesson learn - remove the Training function; Need to learn how to recover stall plane; Do more training in the simulation.