DRAG RACING is the sport of racing cars in a straight line over a fixed distance (typically a 1/4 mile). The object being to get from one end of the strip to the other in the fastest time.

Slot Car Drag Racing is the same but in 1/24th scale. The Slot racing Drag strip is 55 feet long (1/4 of a mile in 1/24th scale), and in this case is powered by 12 volts and up to 100 amps.

Drag racing provides basic raw data as follows:

1) ET - The time it takes from when the lights go Green and the racer responds, to when the car finishes its run on the strip.
2) TS - Terminal Speed - The final speed of the car measured in a speed trap over the last 4 feet of the strip.
3) RT - Reaction time - The time the racer takes to respond to the green light. To establish consistent data it is possible to use an automated start, therefore removing the racer response equation.

THE EDUCATIONAL PROJECT

Groups of students design and build a Drag car using a framework specification and a standard kit of basic parts. The chassis are fabricated from brass and spring steel components with the additional use of Piano Wire, brass tube and soft, silver content solder and flux.

Students may also design and manufacture the lexan body shells utilising vacuum forming facilities at school and then paint bodies to final finish using acrylic paints.

When cars are ready to test, they are brought to Riverside Raceway and test run on the Drag Strip where data regarding performance, ET & TS are noted. In addition to the raw data, notes should be taken on the overall performance of the cars in terms of the way the cars impart traction through tyres etc.

In the Classroom, students may then analyse the data and improve their cars in terms of design.

A further visit to Riverside Raceway will then provide an opportunity to re-run the cars, noting data and improvements made.

The kit supplied also includes various gear ratios, so trials may be made to observe the effects of changing gear ratios on ET & TS times.

Utilising data in the classroom, students may extract further information from the run data such as mean tyre speed and motor Rev’s at TS by noting the diameter of the tyres and TS speed and constructing formula to extrapolate this information.

The aspects of practically illustrating acceleration in terms of Feet per second/per second may also be made.

TS speed is read from the track timers in fractions of a second. Conversion tables to MPH are available however, it may be a further task for students to work out their own formula to convert these times to speed.

Further calculations may be made in terms of energy/effort by weighing the cars and taking into account their acceleration over the fixed distance.

In addition to the purely mathematic, and design technology aspects of the project there is also the possibility of competition between groups and hopefully, an Inter-School Championship competition towards the end of a number of projects.

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