Mousetrap Cars, Various thoughts that need clarification

[Aracon504]

Let me start off by saying I'm not 100% certain that this is the correct forum for this to be posted in, if I'm incorrect in doing so, I apologize.


I've found several threads previously discussed about mousetrap cars, none of which answer the questions I have.

I have four days to design and produce a working mousetrap car that's premesis is to travel the furthest distance. I'm in High School, so it it is a pretty basic assignment, but they will be raced, and I like to research & understand situations the best that I can. So without further adieu:


These are some of the thoughts & questions I have any input/help would be greaaaaatly appreciated.

A) Will using a smaller diameter wheel in the front be advantageous to the efficiency of the vehicle? Or will it hinder by losing surface area traveled? (Note: The drive axle per usual, the rear...)


B) We were debating on using a PVC insert within the frame so that we could better lube the axle and reduce friction between the axle & frame. Thoughts? (Also considered using a type of plastic clip that would allow the axle to be mounted under the vehicle's frame...)


C) Most importantly steering, the width of the wheelbase provides stability, and the length (correct me if I'm wrong) will provide a greater distance traveled...I'm sure there is an optimal point in which these theories achieve a the best possible results. Any ideas whereabouts it is? The maximum length of the cars is 50CM/ No max width.



We will most likely be using a 13 CM arm, but again if for some reason this would be too large, please shoot me some details!



Thanks in advance.

 

[ted12L]

Basically, most of your acceleration is focused on your back wheels. The back would push the whole car forward in order for the whole thing to move. So really, the front wheels should be something like the back, but a little smaller. You want something with the thickness of a CD, but about as small as a spool rod.
What I did was use a hollow plastic tube on top of a slippery marker. The tube is free to be attached to the frame, and the marker, being the axle, isn't interfered with rolling. It also helps the friction because the tube can also roll along with the marker just in case.
Steering depends on whether your car has to travel to a certain point marked on the floor or if the judges measure how long your car goes. If it's to a certain point, you'll have to make the steering almost perfect. Otherwise, it won't really matter. The width matters in the way that weight will affect the car, but it'll also heighten the wheel-axle ratio, if that's what you want. Finally, the length will probably affect the string length to however long the string can be. The longer the car, the more string you'll use, but the more weight there'll be.
Other than all I've told you, it's really a matter of trial and error.