Rubber Band car

[carrier_new]

I have a physics project
make a rubber band car that goes as far as possible
the didtance is counted to where the car stops
anyone have any good desighn or conceptual suggestions, please feel free to guide me
thanx

[ughaibu]

The project is unrealisable as we cant know how far is "as far as possible".

[carrier_new]

i appologize, as I am new to these forums, I have not expressed myself clearly
This project is a CONTEST between students in our physics class, the distance required to get an A is 4 meters, however the winning car in the class will be one that travels the farthest. There are certain rewards for the winner, and that is why I want to maximalize the distance beyond the 4 required meters

[Edella]

Google is your friend. In five minutes I found four different designs for " rubber band car." Do some research ,you'll be glad you did.

[ughaibu]

Carrier_new: I apologise too, I was pulling your leg.

[arkain101]

My thoughts.

Make a perfect system that collects the rubber band as it unravels from your prepullsion axel, as to avoid dragging it on the ground and accidently running it over.

Make sure when the band is done powering the car it releases cleanly from the axle.

Modify the diameter of the part of the axle the rubber band is pulling on.

But, at the same time avoid having the cars tires burn out, slip.. If you can put rubber bands around the tires as to make good traction. Then set-up the car so it accelerates as fast as possible (using the axel diameter modification) but will not burn out. This will give you the best fight over friction.

Then you want to use some very smooth axel bearings of sorts. You can use straws, or washers. But make it so all the wheels spin almost friction free.

Make the car as light as possible and put all the weight where the prepulsion tires reside.

Warm up the elastic bands before winding them up. Keep them in hot water. Then cool them before race time. This will give you maximum stretch, and maximum power.

those are my quick thoughts.

[Boerseun]

Are there any limits on the rubber bands you're to use? Thickness, width, etc.?

Another thing, like Arkain said, make sure your tires don't slip. This will happen very easily, so if you can, wrap your wheels in elastic as well, to give it more grip and traction.

Your drive-train should have the actual axle on which the band unwinds. This should be connected via a step-up gearbox to your driving axle. This configuration won't only give you more speed, but will put more stress on the driving axle, so that the elastic don't unwind at once. It will spread the elastic's propulsion evenly, so that you don't suffer wheel-slip, and get more bang for your buck.

4 meters are for sissies - a wound-up rubber band has a lot of energy, able to push tiny little cars a looong way - as long as you don't make the classic mistakes of wheelslip and direct drive...

My 2 cent's worth of pit-talk...

[moo]

My 1 cent...

The highest power range is at takeoff, so to avoid wheel slippage and store some of the initial energy, use heavy (or weighted) wheels on the drive axle. This serves as a traction aid (without adding extra weight on the axle bearings) and acts as a flywheel (releasing energy after the rubbber band is released).

Release is simple, use a short headless pin on the axle to hook it on and wind it adjacent to the pin so it doesn't hang as it unwinds. Anchor the rubber band above the axle so it pulls upward and will clear the ground when it slips off the pin.

Boerseun's suggestion to use rubber bands around the drive wheels for "stickier" traction is an excellent idea, but I'd enquire about the legality of gearing, rubber band size and max vehicle size. With no limits you could build one to carry the teacher well beyond 4 meters, although it might be kinda hard to wind up...

moo

[carrier_new]

Thank you all!
To reply to the most frequent questions theres no limitations to the car or the number of rubberbands, but ALL the power has to come from rubber bands I've started testing out some disighns and will let you know how i do,
So far legoes work well for the gearbox

[arkain101]

haha, thats awesome.

You could make a hell of a car from the sounds of it.

Its not 'really' about the distance. Your teachers want you to learn what you can achieve when you put your mind to it.

Not many people invent, however its a great thing to learn about while getting an education!

Yeehaw gramma.