Loops just require forward flight..the faster you fly the faster your inputs need to be.

Or just get up real high (as high as you can safely judge orientation) and do a flip. The higher you go the better chance you have for a safe recovery...if you make a mistake.

either way, give alittle positive collective as as you pull back on the cyclic. when you get to the top of the loop/flip give a little negative. Then feed in a little positive as you nose down the the back side of the loop.

If you don't feed in the negative pitch the Heli really loses altitude quickly on the back side of the loop.

For faster(stationary) flips make bigger control inputs...once you get the timing down...your heart won't be in your throat.