When I learned to loop, that is the only mode we had. You can do it. Do it high and don't let the rotor speed slow down. Don't try to do it too tight and make sure you keep flying it when you come out of the loop. Don't try to loop into a hover. Keep your forward speed up. Get it set up for idle up and you will find it a lot easier. You can keep the rotor speed much better. You will be find for now though.

Good luck. Start high.