Red, I think you answered your own question, if the airplane is tailheavy it will do that! Buf first things first, if didn't track straight, that's normal for a taildragger like a Cub because of the engine torque, but the way to apply rudder is to do it gradually as you need it to keep it straight on the runway and not overapply rudder. I suspect that maybe after take off you held the rudder for too long and that coupled with the tailheavy attitude caused the plane to bank right and hit the ground. You should make sure that the airplane is properly balanced at the correct CG (extremely important!). For better tracking on the ground, I recommend putting a little tow in on the wheels. Try it again and remember apply rudder gradually, and as soon as it takes off get off the rudder and also climb gradually. Hope this helps!