Grand Prix Racing - The Science of Fast Pinewood Cars

Drifting Means Bumping Into Things

I guide you in the way of wisdom and lead you along straight paths. When you walk, your steps will not be hampered; when you run, you will not stumble. Hold on to instruction, do not let it go; guard it well, for it is your life. Do not set foot on the path of the wicked or walk in the way of evil men. Avoid it, do not travel on it; turn from it and go on your way. For they cannot sleep till they do evil; they are robbed of slumber till they make someone fall. They eat the bread of wickedness and drink the wine of violence. The path of the righteous is like the first gleam of dawn, shining ever brighter till the full light of day. But the way of the wicked is like deep darkness; they do not know what makes them stumble. Proverbs 4:11-19

Whoever loves his brother lives in the light, and there is nothing in him to make him stumble. 1 John 2:10

Just like the race of life, the Grand Prix experience does not guarantee the kind of smooth sailing modeled in the simple closed race equations. But by illuminating the causes of the many challenges that want to derail our progress, we can find instruction to help stay on the straight path. In addition to the usual challenges, there are bumps, pits and all sorts of possible unfortunate situations (usually dealing with mishandling of cars). Of these, there are those that can be anticipated and those that can't.

One purpose of this manual is to explore all the possibilities that can be anticipated. Many of these possibilities have been discussed in the physics of design and the track's effect on the car. These are examples of things you can exert some control over through good design and craftsmanship. Drift, in large part, is more illusive. Models describing drift depend on the history of your car's path on the track, its tendency to turn and the way it reacts to irregularities on the track and correction via the lane median. Effective strategies to combat drift can rarely be based on start to finish race models, rather the type of models developed are for specific events or limits of drift caused behavior.

As with drift, the impact of our sin on our lives is difficult to determine, though we can see that it hinders us from knowing Jesus better and loving one another. No wonder strategies to successfully combat our own temptations are often role-modeled for us in specific events of stories in Scripture. Such stories paint a great background for reflecting on this important aspect of Christian life as you investigate these pages.

Drifting On The Track

Drifting is the deviation of your car's path from the "perfect" trajectory developed in the closed model solutions of this manual. Your car will not follow the perfect path precisely. How much it deviates will be determined by what you do when you put your car at the starting gate, and what you did to align its wheels and prevent collisions with the track median.

The paragraphs below summarize some effects of drift caused by your wheels, track and median events. They are expressed in terms of speed, energy loss and various limitations of those effects. In this way you will be able to tell which aspects of drift are the most important for you to avoid and which are most likely to be a problem for your car design.


While trying to put this puzzle of many interactions together, think about these diverse questions:

The cause of this wandering may be

You will undoubtedly have many more questions as we attempt to find some limits and "ballpark" figures for some of the effects of drift discussed. Below is a sampling of the results.

Effects of Drift
Median Impact Angle up to 5.5 degrees
Number of Median Collisions upto 93
Wandering Car* up to 5.5 inches or 0.035 seconds more
"Garanteed" Median Hit over 0.03 degrees off straight at starting line
Elastic Median Collision up to 1% energy lost each time
Inelastic Median Collision up to 1% energy lost each time
Wheels Toed in or out up to 34% increase in friction
Wheels Rubbing Median up to 1/2% of energy lost per foot

* Not accounting for median impact energy losses

Alignment and Interaction

There are two sides to drift; alignment and interaction. If you align your car, you have hope there will be less interaction with the track - usually the lane median. But even if your car is aligned, some interactions with the track can affect the path of your car and make it waste energy wandering aimlessly. Your car will use these interactions for correction or be spurred on to wayward behavior.

Alignment affects both the path your car takes and to a smaller degree the way it responds to collisions with the lane median. So in the models we will first look at the path and speed of the car (motion or kinematics) and then try to understand the forces and other dynamics. The goal is to find some ways to minimize drift.

  1. Straight and narrow is the road to the finish line is a look at the motion (kinematics) caused by drift. It helps us see the limits of drift and gives us some expressions for more analysis.
  2. Interactions with the lane median are modeled in Drift Dynamics.
  3. One of two types of collision dynamics will keep your car Bouncing back.
  4. A wayward car is a grief to its racer, especially when the other type of collision dynamics take over.
  5. Some strategies for avoiding certain effects of drift can be found for Reducing Drift.
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Grand Prix Racing - The Science of Fast Pinewood Cars
Copyright © 1997, 2004 by Michael Lastufka, All rights reserved worldwide.