# Self propelled car

1. Oct 5, 2011

### Auxitras

1. The problem statement, all variables and given/known data

hi! first off, thanks for viewing this. I wasn't sure if this would be the right place to post for help, but it's for an engineering challenge so I didn't know where else to go. Also, I'm really sorry if this is a repeat thread, I don't really have time to read through them, and am actually going to be doing some trials on what i already have while I wait for responses.

Basically, I have to build a self propelled car that can go up a ramp (which I need to build as well) and travel 1.0 meters horizontally in the air. The height the car gets isn't measured.

Coinstraints:

-The entire propultion mechanism must be on the car. So I can't use my slingshot-on-a-ramp idea D:

-The method of propultion cannot use electricity, explosions, or chemical reactions. I can't afford to buy a bunch of CO2 to use in testing, so I suppose that's out as well. :S

-The car must weigh between 0.1 kg to 2.0 kg.

-The car can be bought but the method of propulsion and ramp must both be made from parts I assemble.

-The ramp can only be a max. of 1.0 meters in length, but there are no height restrictions.

2. Relevant equations

I don't even know... :P

3. The attempt at a solution

At the moment I have a chassis made out of K'nex and am using a balloon as an elastic to turn the axle after winding it up the other way. The wheels are the biggest I can use without using massive gears and have rubber bands on the outside for traction. I was also playing around with a balloon for air pressure, but it doesn't really create enough force to move the car at all.

Last edited: Oct 5, 2011
2. Oct 5, 2011

### Staff: Mentor

Welcome to the PF.

Have you seen those little toy cars where you put them on the ground and roll them back a bit (maybe 25cm?) and when you let them go, the stored energy makes them bo pretty fast? I don't know the name of the toys, but they are pretty common. You might get one of those and take it apart for ideas on how to store up the energy. The car must use some sort of circular spring mechanism or something. It's so small and light, that it gets going pretty fast, and I'm fairly sure it would clear a horizontal meter with even a small ramp.

At least it might give you some ideas. I'm guessing that a small, light car with a strong spring mechanism to drive the wheels will work out well. The spring obviously needs to release the wheels when the spring energy has been delivered.