For Glow airplanes I would not fly with out at least 100 clear acres. Glow planes are 10 too 100 times faster than electric. Your reaction time is not that great. It would just be a matter of time before you would do damage to property of GOD forsake a human being. Saw a pilot lose control and crased into a automobile. The crystal vibrated out of the receiver. The engine went completly through the drivers side door!!!!!!!!!!!!!!!!!