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Mousetrap car and vehicle propulsion

By Doc Fizzix // Published Feb 02, 2005

A mousetrap powered car is a vehicle that is powered by the energy of a wound-up mouse trap's spring. The most basic design is to tie one end of a string to the tip of a mousetrap's snapper arm and then the other end of the string has a loop that is designed to "catch" a hook that is glued to a drive axle. Once the loop is placed over the axle hook, the string is wound around the drive axle by turning the wheels in the opposite direction to the vehicle intended motion. As the string is wound around the axle by the turning of the wheels, the snapper's lever arm is pulled closer to the drive axle causing the mousetrap's spring to "wind-up" and store energy. When the drive wheels are released, the string is pulled off the drive axle by the mousetrap causing the wheels to rotate.

Step #1:
A string is attached to the mouse trap's lever arm and them hooked to the drive axle. The string has a loop knot tied at one end that is designed to "catch" a hook attached to the drive axle. The string's loop knot is designed so that the string can release itself after the pulling force is spent. If the axle's hook is too long or the string's loop knot is too tight , the string will not properly release from the axle causing the vehicle to suddenly stop.

Step #2:
To wind the string around the axle, the wheels are turned in the direction opposite to the motion of the vehicle's travel. It is important that the string NOT be wound loosely or it will snag itself as it is pulled from the axle by the lever arm, the string should carefully be wound tight and uniform around the axle. Do not push on the mousetrap's lever arm during this process, you want the string to be tight and to pull the lever arm over.

Step #3:
Once the car is released, the string is pulled off the axle it cause the wheels to rotate propelling the vehicle. If the mousetrap is located to close to the drive axle the wheels can spin at the start wasting energy.

See the following related articles to get started:

• how to make a mousetrap powered car
• making a good distance traveler
• making a good speed-trap racer