On a smooth track such as the New South Wales track I doubt that suspension would
make any difference except to add weight and consequently slow the car down.
12 Construction materials
The regulations allow the use of any materials. Some important considerations in material
selection are: cost, availability, workability, toxicity, stiffness, durability and strength to
weight to stiffness ratio. (See Part D on material specifications for data on some suitable
materials). Do not overlook common materials. Some very good cars have been
constructed from balsa wood, plywood and common plastics.
Caution: We have seen very well made car bodies in balsa wood that fell apart after
racing in wet conditions, only because they were not sealed and soaked up water.
13 Body
A body can improve the looks of your car, but take care that it does not weigh too much.
Clever design can produce a body with sufficient strength to hold everything together
without the need for a separate chassis. Effective streamlining of a body can significantly
reduce aerodynamic drag. This is more important the faster the car goes as drag varies
with velocity squared. In 2 lap races the car runs the second lap at near maximum speed
making aerodynamic drag a very significant factor in these races. Do not ignore the
underside of the car a significant amount of drag can occur in this area.
Remember a body can be as complex as a carbon fibre shell or as simple as a sheet of
plastic or cardboard folded into a body.
Regulations for 2011 require a drag plate of 200 square cm area, this plate if not
contained within an aerodynamic body will create significant drag. There is however a
trade off between reduction of drag obtained by using an aerodynamic body and the
reduction in performance due to the extra weight of bodywork. Mathematical modelling
indicates that a lightweight aerodynamic body cleverly designed to contribute to the cars
structural strength will give a significant performance increase compared to a car without
aerodynamic bodywork.
14 Track
The Victorian track consists of sections of painted plywood joined up to form a figure of
8 with a bridge at the crossover point (see the Regulations for details). There will be
some mismatch at the joints of both ply sheets and guide rails. Be sure you allow for this
in your design.
Car design should allow for vertical mismatch up to 2 mm at the joints between track
sections and dips (undulations) of up to 10 mm over the length of a section (2400 mm