Rocket Cars

I did this a few years ago.  My results were:  The rocket car left the ground, I scared the heck out of the people at the other end of the parking lot, and I spent several minutes looking for all the Lego parts all over the parking lot.



My recommendation is that you build the car heavy and lighten it up after a few tries, use only Lego that you can stand to loose, build the car as stout as possible, and plan to look for Lego parts all over the place.