expelliarmus

ok... i've looked through previous threads on similar problems, and haven't found anything quite what i'm looking for... i need to create a car out of things that aren't car-related (cardboard seems to be a popular option) it can only be powered by rubber bands, and i can't push it, fling it, etc. it needs to go at LEAST 20 meters... the farther, the better. if you have any ideas of how to make a long distance one, please share!!! right now i'm thinking of making one with 3 CD's for wheels, two in the back one up front. connected by cardboard and chopsticks as axels. then i'd put a small plastic propeller on the back, and attach a rubber band to it, anchoring the band on the opposite side of the car. by twisting the propeller, it would spin the band, then when released, it would unwind, twisting the propeller to give thrust. is this the best long-distance design??? please help!!!!