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Mousetrap Vehicles: Weight Distribution

February 03, 2012

Weight distribution is how the mass of an object is spread out or its area. Learn all about weight distribution and how it applies to mousetrap powered vehicles.

Mousetrap vehicles are complicated machines with a multitude of variables that effect the vehicles performance that few people with think about as they design their racer. Weight distribution can have a large effect on a vehicles performance, if the weight of a vehicle is concentrated to far away from the drive wheels there may be a greater tendency for slippage at the start line. And if a vehicle's weight is placed to close to the drive wheels there may be the possibility for steering issues.

bonus tip: Heat and sound are forms of energy caused by friction.

Wheel Slippage

Speed-trap racers require a lot of torque at the start line in order to get to top speed as fast as possible. Slippage occurs when the drive wheels do not have enough traction on the floor. Traction can be controlled by the "grip" a wheel has and/or the amount of weight pushing a wheel onto the flooring. For these top-speed contest it is a good idea to center a vehicle's weight near it's drive wheels in order to increase the traction. When you think of building a super fast mousetrap racer also think about the design of a top fuel dragster, most of the weight of the dragster is concentrate over the drive wheels in order to increase traction and improve the dragster's acceleration off the start. As the center of mass of a vehicle is moved away from the drive wheels the traction also decreases.

bonus tip: center weight closer to the drive wheels in order to increase the traction and the maximum acceleration.

Changing Weight Distribution

With some mousetrap vehicles long lever arms can change the dynamics of a vehicle performance by changing the weight distribution during a vehicle's run. Depending on the design of a mousetrap vehicle's lever arm and the lever arm's weight, the position of this lever arm can change the weight distribution over the wheels causing a mousetrap car to turn and/or not travel straight. As a long lever arm starts it's travel the weight is centered closer to the rear of the vehicle, but at the lever arm makes it way though it's power stroke the weight is shifted from the drive wheels to the non-drive wheels. This shift in weight caused by the lever arm can cause a vehicle that starts out traveling perfectly straight to begin turning as the power stroke comes to an end.

bonus tip: as the position of the lever arm changes so does the weight distribution of the vehicle on the wheels. This can cause a vehicle to wonder or not travel straight as it travels on it's journey.

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