I've been told that commercial airliners fly with a thrust:weight ratio of 1:3, so I guess it can be done. For model planes, you typically want 1:2 or higher. If you can get 1:1 or higher, then the plane can climb vertically on it's own thrust, and it will be much more aerobatic. With less that 1:1, you need to fly "on the wing", that is you need some forward speed to keep it in the air. With greater than 1:1, you can keep it in the air with prop/edf thrust alone.