THIS critical study of the possibilities of improving automobile performance and economy by aerodynamic refinement is begun by demonstrating the analogy between motor-car air-resistance and airplane parasite-drag. An example is then cited to illustrate the benefits of aerodynamic research in the latter field and to point out the potentialities of similar work in the former.
Consideration of practical requirements and limitations in an analysis of motor-car air-resistance leads to the selection of a rear-engine arrangement as the most promising type and to the prediction that its air resistance will approach one-fourth that of conventional cars.
This prediction is confirmed by the results of wind-tunnel model-tests. Full-scale replicas of the models tested would provide adequate passenger accommodations and engine space without exceeding accepted overall lengths. Combination of the test results with reliable rolling-resistance data indicates the possibility of reducing current power-requirements by 19 to 55 per cent at speeds of 20 to 60 m.p.h.
The author expects rapid obsolescence of the present or “horseless-carriage” type to follow the appearance of streamlined, rear-engine motor-cars.