http://www.youtube.com/watch?v=MAWa9uxtZj4

Check out that video of a relatively mild ground loop (no bent wings).

I know I am going to butcher this but i'll try. In tailwheel a/c the CG is located behind the main wheels. So when you touch down the with the aircraft pointed in any direction other than the direction the aircraft is tracking (ie....improper x-wind correction) there is a destabilizing moment induced on the aircraft. Not a huge deal on tricycle aircraft due to the CG being forward of the mains and the wheels absorbing the side load. Now imagine all that force behind the mains when the tailwheel touches down. The tailwheel acts as a huge lever due to its location so far behind the CG. Once the tail starts tracking around, momentum kicks and and physics does the rest. Clear as mud? My instructor would probably cringe if he saw this explanation of a ground loop...lol. Now groundloops are not always a bad thing. In the case of losing an engine and being force to put it down in a small clearing it can significantly reduce your land roll. Not the greatest thing but it sure beats hitting a tree and totaling your aircraft.

I can still hear my instructor saying "there are those who have, and those who will. Fly the airplane to the chalks!" If you want a fun challenge go get your tailwheel sign-off. I got mine when I was instructing and it was proabably more fun than any other flying I had done up to that point. It will make you a better pilot and bring a greater appreciation for x-wind controls even while taxiing.

If there is anyone who can offer a better explanation of this please do.

If you would like to know more check out this book. It will tell you more than you ever wanted to know about tailwheel aircraft.

http://www.pipercubforum.com/compleat.htm