Design for Speed

If you want to make a really fast Grand Prix car, you need to know which design factors increase your car's available energy and which ones decrease it. You must start from your initial design to get the most in speed. Some races judged by electronic timers have been decided by one thousandth of a second (that's less than a quarter of an inch at the finish line).

There is probably NOT a single BEST design. Given the competing nature of some of the performance factors and track shapes, there IS room for difference in design. Though cars shaped like high performance grand prix racers may win, a car designed by following these procedures to the letter will tend to look more like a dragster. These cars should win more often given the wide range of Grand Prix race tracks and judging.

Factors That Increase Energy Available for Speed

1. Length of your car
2. Location of your car's balance point
3. Total weight of your car

Factors That Decrease Energy Available for Speed

1. Rubbing between axles and wheels
2. Resistance of your wheels to spin
3. Wheels that bob up and down (your car is not flat on the track)
4. Wheels that are not aligned straight
5. Rubbing between the air and your car
6. Rubbing between inner wheel hubs and your car body
7. Rubbing between axle heads and outer wheel hubs

Each of these factors must be dealt with in some way in the design itself because they affect each other. For example, in order to place the balance point where it should be, you will make your car body as light as possible. This allows most of your car's weight to be free weight that can be precisely positioned in the rear of your car. However, the nose of your car may become so light it could hop off a bumpy track!

If you make the body too slight, how will you secure the free weight to the car or keep it from breaking when it hits the pillow or blanket at the end of the track? So there are real trade-offs with real consequences to be judged and weighed in the design of your car. How much of a risk-taker you are may determine how you apply the procedures in this manual.