This is NOT my creation. It was made by user PG52 on eurobricks.com. There is a whole thread on there discussing such build. I did not create the LXF file either. I simply made slight modifications (all white parts) for either stregthening the build, making it kid-proof, or using more common parts (Connector #3) instead of more expensive ones (e.g. cardans).

http://www.eurobricks.com/forum/index.php?showtopic=87974&st=0
http://www.youtube.com/watch?v=BonmtQCiVgg&feature=player_embedded