Rubber band car

[App13]

For physics class we are building rubber band cars. The only rules are that it must go 3 meters and cannot be powered via sling shot. Right now I just plan on having a fixed point in the middle, some sort of catch on the rear axel, and wind it up.

Now she did say we could collaborate, so let us, as a community of fencers, collaborate.

Any ideas/help?

[AlphaFire X5]

How many rubber bands are allowed? Can you use a small electric motor and use the rubber band as sort of a belt-drive system? Can you use springs?

Loopholes, man, gotta make use of them!

[App13]

2 medium sized rubber bands, must be completely rubber band powered.

[parrythis]

Back when I was a kid - before Toys-R-Us even existed and we had to make our own toys - we used to take the empty spool from a spool of thread and slip a rubber band through it. On one end of the spool we would insert a broken toothpick - no longer than the diameter of the spool through the loop on one end of the rubber band. On the other end of the spool we would insert a whole toothpick through the loop at the other end of the rubber band.

Wind the rubber band up by spinning the whole toothpick around repeatedly, then set the spool on the floor, let go, and watch it scoot away - easily further than 3 meters if you wind the rubber band up enough.

[noodle]

Originally Posted by App13

For physics class we are building rubber band cars. The only rules are that it must go 3 meters and cannot be powered via sling shot. Right now I just plan on having a fixed point in the middle, some sort of catch on the rear axel, and wind it up.

Now she did say we could collaborate, so let us, as a community of fencers, collaborate.

Any ideas/help?

that would be, basically, the best way to do it. from there, its just minor changes.

[parrythis]

Originally Posted by App13

Right now I just plan on having a fixed point in the middle, some sort of catch on the rear axel, and wind it up.

Make sure the rubber band can detach from the catch when its energy is fully expended so the car can coast if necessary.

[Rabid Monk]

3 meters? That's it?

Easy.

Use records for drive wheels (size depends on the power of the rubber bands).
Have the elastic bands positioned so that they are just starting to stretch when they reach the winding peg.
In first-year Eng Design, we had to build an elastic-band car for distance. My group built it out of 2 large records, and an old childrens roller-blade (cheap, from second-hand store) which gave us one follower wheel and many smooth-running bearings. The elastic was suspended off of a post of "lamp rod". I also made an attachment out of the last 18" or a fishing rod, for extra oomph. For some reason, the other groups objected. Even without, the car made an easy 20 meters before running into the doors.

Another very good design is two CDs on the ends of a toilet paper roll, with the elastic running through the middle and pushing a stick against the ground. That was the design that beat my groups. Primarily because it went straigtht, where ours turned a little (maybe 2 feet over the 20 meters) and hit the door.

[mikeb]

Check this website out, may give you some ideas!!

http://www.youthideas.co.uk/yw/act/car/index.shtml

When i was doing my mechanical engineering degree we had to build a catapult with an elastic band, two tooth picks and some balsa wood. Was great fun!!

[App13]

I just got my grade back, A-.

[Rabid Monk]

Originally Posted by App13

I just got my grade back, A-.

Congratyulations.
We, however, demand pictures, or at least diagrams, of your car.

[App13]

My teacher asked to keep the car as an example, but I can whip up a 3ds image some time.