Grand Prix Racing - The Science of Fast Pinewood Cars

More Drift Dynamics

The level of detail in the drift models is superficial in many ways. They could be made much more elaborate by using probabilistic approaches, but they would be less easily understood and perhaps not much more would be gained. Making measurements for any of the proposed drift models would be more difficult than those for the straight race models.

In an attempt to be complete, there are a few areas of drift dynamics that can still be mentioned beyond those that could be modeled.

Drift Angle Changes With Speed

As a non-squared-up wheel speeds up, its momentum increases. The increase seems to cause the wheel to role along a longer arc. In fact, there seems to be a critical speed where the wheel takes a hop on its edge and trips over itself.

But wheels are raced attached to a car! Forces pushing down on the wheel through the axle probably damp out much of this arc-lengthening. So until precise experiments can be performed that isolate this behavior, we won't know for sure if this behavior actually occurs in a race.

If it does, then the sideways forces of these poorly shaped wheels may not increase as much as one might expect with speed.

Bobbing frequency not speed related

As wheels bob, they cause momentary accelerations to the side of the car. These torque the car to turn in toward the side the dragging wheel is on. If the wheels bob continuously, they tend to bob at a natural frequency that is not affected by the car's speed.

Only the distance between track contacts and therefore the torque depends on the speed the car is travelling. The torque depends on the moment of inertia of the car body around the vertical axis. Longer wheel base cars would be most susceptible to this effect when the center of mass is in the middle of the car. A long wheel base car with a center of mass near the rear or front axle can not bob.

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Grand Prix Racing - The Science of Fast Pinewood Cars
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