Actually, we see wannabe (or maybe not) terrorists and criminals on RCU on a regular basis. I'm not accusing you at all, but they ask questions very much like yours and are secretive like you are being. So it's natural for someone to be suspicious.

To answer your question, a Senior Telemaster with a 20cc engine would be just the thing. I'm sure you could put enough fuel tanks in that cavernous fuselage to drag a glider around for an hour if you wanted. And Telemasters are easy to fly and land. That plane is meant for a .60 glow engine, while the 20cc is about twice that. Balance will probably require relocating the servos, flight controller, and flight battery to the back of the plane, which won't be hard to do. That will free up the area around the CG for fuel tanks. The huge wing won't mind the extra loading at all.