mousetrap car design help

Questions:

My Mouse Trap Car Suddenly Stops?

By Doc Fizzix // Published Nov 16, 2005

Answer:
If your mouse trap car suddenly comes to a complete stop then there must be something that is causing the wheels to locks-up or preventing the wheels from turning, most commonly we find that the pulling string is too long and begins to tangle or re-wind around the axle eventually putting the breaks on the racer. Also, the axle hook is some times cut too long and snags the string as it unwinds from the drive axle. Another common problem that could cause a car to come to a sudden stop is too much rolling friction on the axle points.

Try the following to correct the problem:
• Make sure that the sting is "just" long enough to reach to the drive axle, in theory the string should only be twice the length of the lever arm or best a little bit shorter but never longer.

• Check the axle hook and trim make sure it is no longer than 2 millimeters or it can catch the string as it unwinds causing the vehicle to stop.

• There may be too much friction at the rolling points between the axle and the frame. Make sure all axles spin freely and that nothing is binding against the frame of the vehicle. You can also try re-doing the axle-frame points by making the axle holes a little larger and then make sure you use some graphite powder on all friction points.

More information is available on friction: What is Friction?

See the following related articles to get started:

• Axle Friction (thrust washers)
• making a good distance traveler
• making a good speed-trap racer