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Q & A: A boat race using rubber bands?

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Most recent answer: 08/26/2010
Q:
Hey, I am studying mechanical engineering and we just got a project where we have to make a floating vessel that transports a coke can over a distance of 12 meters in a swimming pool by making use of only 4 elastic bands as a source of energy. Im hoping that you might be able to help with what the best materials to use would be and maybe some ideas on how to get the most propulsion from the elastic bands. Im thinking of building a catamaran with paddlewheels turned by the elastic bands. Maybe make hollow bases that il fill with helium to make the vessel lighter and thus minimizing the drag that the water would create. The biggest problem is getting the most energy out of the elastic bands. Thank you Ruaan
- Ruaan Coetzee (age 26)
Cape Town, South Africa
A:
What a wonderful project!  There are so many ideas to explore I wouldn't know where to begin.  You might study how much you can stretch the rubber before it breaks, since the energy stored is approximately proportional to the square of the stretch.   You might explore linear vs. torsional extension.  I remember flying model airplanes as a boy.   I used a twisted rubber band to drive the propeller.  If this is not a race, forget about drag.  If the boat goes slowly there is hardly any drag.   Good luck, and be sure to have fun!

LeeH

(published on 08/26/2010)

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