King of the Hill Contest - need your input

[ksettle]

we're doing a project for an engineering design class where we need to build a vehicle that will climb a 40 degree incline and then hold its position at the top of the ramp against an opponent that is coming up the other side. (there are ramps coming up two sides with a plateau area on top)

I don't have much experience with r/c vehicles, but I think starting from an r/c truck or tank is our best bet. I am mostly concerned with finding a vehicle that can climb the incline with no problem.

some of our constraints:

less than 12in x 12in x 12in
less than 2 kg (approx 4.5 lbs)
powered by batteries 9V or less

Any suggestions for a model to start with would be appreciated. We are hoping to stay within a budget of about $100.

[TEM]

Could you be a little more specific? So you just keep going forward and push your opponent back down his/her side of the "hill"? Or in otherwords, you are making a vehicle that keeps moving forward with as much torque and grip as it can get? Whats the ramp/hill/whatever made of? What other constraints are you under?

[ksettle]

there is a center line at the top of the ramp...whichever vehicle has their front end closest to that line at the end of 15 secons wins...so basically we have to either push them out of the way or jsut get there first and maintain our position...so yes we need torque and traction, but it can't be too slow either

the ramp is covered with an indoor/outdoor carpet like material...enough friction that traction shouldn't be an issue going up the incline...the ramp is about 12 inches wide with 2 inche guide rails.

some other constraints....the vehicle must be autonomous....we will need to direct wire it through a switch...we can't actually use the radio

the vehicle must have a stopping mechanism, somethign that turns it off at the top of the ramp

[TEM]

Autonomous, so no controls... ok and carpet material. First to get to top and not get pushed off, and needs to stop automatically. Ok, build a car that moves fast on 4 wheels, use a ribbon or similar that wounds around the axle that will trigger a switch at the end that does 2 things. 1 it will stop the wheels from driving forward and 2, it will engage a spike loaded board that will lower itself onto the carpet, perhaps even lifting up the rest of the vehicle. The only issue with this one is it must reach the top before the other car. Thats the speed approach.

Torque approach would be a forward moving car/tank with spiked wheels or track that moves forward and will automatically stop itself after a certain distance or time. This car must be able to outpower the opponent.

Something else to consider?, designing the front of your car like a ramp and very very low ride height. The other car just might run over you and leave the ramp! How about a forklift design with an adjustable fork depending on opponent type. no center wheel, use center fork, center wheel, use side fork. thin thin fork, engages as soon as opponent drives over it and forward and hits a switch.

Can your car change form after the start? Ie, can you morph to extend past 12" size restriction? then you can build a car that shoots a tongue up the ramp, the end of the tongue right at the top of the ramp, and the other car will run over you or not(in which case, you got there first!)...

Lots of ideas. But look at what you are capable of building and the constraints...

[rocknbil]

the ramp is covered with an indoor/outdoor carpet like material...enough friction that traction shouldn't be an issue going up the incline...

This is very important, traction is ALWAYS an issue unless you're using thumbtacks on wood for tires/tracks. What type of indoor/outdoor, the green plastic kind or ozite?

The green plastic kind would require one set of traction, the ozite another.

[Combatcm]

Designing it with more weight in the front should help it be less tipsy going up and have a better grip.