After lift off, copter tilts left and therefore slides sideways. Doesn't rotate.
Something I can adjust to stop?
I assume you have the radio that comes with it?
The heli will always have a little tilt to it, have you tried adjusting the trim tab? If you
have your trim all the way over and it's still drifting your going to have to adjust the length of the servo
arms on the heli (make sure your trim tad is set to center before you adjust them).