Streamlining |
Essay by |
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July 1948 | |||||||||||||||||||||||||||||||||||
Why streamline? Any discussion of streamlining must take into account the purposes for which the articles to be streamlined are to be used. A refrigerator or radio, for example, may be designed to fit into modern surroundings and may have pleasing outlines and yet cannot properly be called streamlined because there is no passage of air at high speed to be considered by the designers. A car that is to be driven at fairly high speeds is a different proposition. Too many millions of words have been used to justify curved fronts, slanted fronts, rudder-like tails, etc., when the real purpose of most of those new shapes was to lessen the resistance encountered by the customer's dollars passing through his hands on the way to the dealer's till. Real aerodynamic considerations would rule out most grilles, fenders, and tops as inefficient, but there are too many other factors to consider to let the air-minded engineers have their own way. A car is a vehicle and not a projectile, and the occupants deserve room to sit in and room to carry their belongings. Streamlining that cuts down interior space or that adds too much weight is not a move toward efficiency, but the opposite. A long tail and very low lines will reduce wind resistance at high speeds, but driving and parking a car with those characteristics carried to extremes would be a nightmare. It is easy to prove that properly faired fenders and body lines will reduce gasoline consumption at any speeds but the lowest, but is it as easy to prove that the total cost of motoring is thereby lowered? Some of these new bulgy cars are going to add a lot to the cost of body work. Don't get me wrong; I am not in favor of going back to vertical windshields and air-catching protuberances. I just want to mention a few little things that are too seldom considered when modern car design is discussed. The modern car is, on the whole, aerodynamically efficient; but a few aspects of the problem have been neglected by most makers. Not many cars are streamlined underneath, where the air really whistles through under conditions of extreme turbulence. Most ventilation systems increase wind resistance, but even the most efficient car would be of little use to passengers rendered unconscious by asphyxiation (passed out, I mean, chum), so we have to take a loss in one way to stay comfortable in another. An interesting question to think about is whether a streamlined pan under a car would make the car unstable at high speeds because of the lift given by the shape of the pan. It should be possible to design a pan with negative lift, according to Bernoulli's law, which says that air in motion has less pressure than air at rest. So it would probably be practical to design a pan that would pull the car down, especially at the rear end, and thus improve road-holding at extreme speeds. Maybe somebody has already done that, but I haven't seen it and will have to consider it just a theory. Streamlining is not entirely up to the designer; the car owner can make or break the finest designs. We all like to drive with windows open on a hot day; that adds to wind drag. We like to add gadgets and extra lights, horns, chrome decorations, etc. that all have their little bit to add to the drag. But for my part streamlining is not important enough to deserve the sacrifice of everything else, and is only one of dozens of qualities needed in a really efficient car. One passing shot at the car designers: why should a radiator that is intended to inhale air be streamlined; and why should a grille be installed to "protect" the radiator, grille guards mounted on the bumpers to protect the grille, etc., when for real efficiency the radiator should be right out where the wind is so it can be made as small and light as possible?
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© 1948 Wilfred R. Franson |
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reprinted in — |
More by Wilfred R. Franson Transport at Troynovant |
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