I successfully maiden my new VTOL plane. Thanks to Tridgell and all developers who made it possible with the great ArduPlane sw.
The idea come from a youtube video, unfortunately the poster dissapeared after posting the video, so I had to figure out most of the things. Fortunately I'm pretty familiar with the ardupilot code and posts in the VTOL topic helped a lot as well.
Why the NIMBUS is ideal for VTOL ? Because the motor mounts are easily modifiable to VTOL without adding any significant weight. The total VTOL conversion adds about 360g to the original weight.
It needs some tuning (Try 3.8.2, Set transition airspeed higher, autotune, etc etc...) but even without fine tunings it flies basically out of the box...