Factors Influencing the Forward Acceleration of a Gravity Powered Soapbox Race Vehicle

This paper presents the factors influencing and the corresponding derivation of a mathematical model for the forward acceleration of a gravity propelled race vehicle. It can be applied to scale model designs or full size vehicles as typically used in “soapbox Derby” racing events. Study of the model should clarify the main factors and design parameters that influence the acceleration downhill, and deceleration on the level. Maximising the forward acceleration, particularly initially, is a key performance characteristic in reducing the elapsed time of running. The model was used successfully in the design and construction of a full size competition winning vehicle and offers a potentially useful design tool and teaching aid for studies in vehicle dynamics.