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.
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.
