Fantastic project. One disagreement:
Yes i was thinking that, probably is going to be a big problem, if the receiver fails, the servos will be freeze and airplane BOOM!!!.
Wouldn't this be a great place for a failsafe command set?
Certainly, it depends on what sensors are aboard (horizon detector can tell you "up", compass direction, GPS location, etc.)
At a minimum: If you lose the receiver, neutralize elevator & ailerons, idle throttle (or 1/2, or?). If your aircraft is semi-stable it should return to a flight attitude on its own. If you have a horizon detector, you can be even more sure of it.
Got more sensors? Fly to a GPS coordinate (your flying field?) and circle, again waiting for a signal. If no signal after orbiting the field for 2 minutes, fly to a coordinate downwind of the runway, turn to runway heading, cut throttle to idle. With a little luck your hardware ends up in just a few pieces at your flying field rather than a bajillion pieces lost in a lake, highway, forest...