WAYS OF THE WILD.

Auckland Star, Volume LXVI, Issue 140, 15 June 1935, Page 1 (Supplement)

WAYS OF THE WILD.

STREAMLINING. NATURE SEEKS MINIMUM OF RESISTANCE. (By A. T. PYCROFT.) It is quite recently that man has turned to Nature for those graceful lines seen in some forms of animal life which lessen resistance to the medium, water or air, through which the animal passes. Streamlining in name has recently been adopted in the' building of motor cars and motor omnibuses, but the streamlining of airships and aeroplanes is nearer to Nature's models. Harold Ward, writing in the "National History Magazine," states: "For the most part streamlined motor cars are not streamlined at all. A major difficulty arises from the fact that motor cars, properly designed, for instance, for travel against the wind, are improperly streamlined when the wind blows from any other direction." D. C. Sayre, a capable aeronautical engineer, states: "When aeronautical engineers are told that this year's automobiles, for example, have greatly reduced their air resistance by adding false grills to their radiators and terrible looking excrescences to their lower rear ends, and by rounding off a few corners, they laugh loud and ribaldly. Making a 5 per cent change in last year's car and labelling the result streamlined, they will tell you, is like chromium-plating the knobs on your grandmother's brass, bed and hailing it modernist." Nature's most perfect example of .streamlining is not to be found among, birds, but among some of the marine mammals and fishes. The killer whale and the tuna are outstanding examples of Nature's streamlining. The tuna is the more remarkable, for, at high speeds, the spinous dorsal, the pectoral and the ventral fins fold against the body. The porpoise is another example of Nature's streamlining. A dirigible probably illustrates one of the most perfectly streamlined forms that has yet been developed for practical use by man, and resembles a porpoise in shape.

Effects of Wind and Air Currents. Actually a sedan motor car of the type which most of us see, drive, or ride about in, is wasting a full half of its power at 30 miles an hour in overcoming wind resistance. Nasty little air currents churn around the radiator, maul the windshield, whistle along the protruding fenders, ' and whirl in a thousand suction vortices behind the truncated rear end. Increase the speed to 70 miles an hour, and five-sixths of your petrol bill is paid out for the same purpose. No wonder streamlining, from golf sticks to trans-Atlantic liners, has become more than a passing fashion. Fuel and lubricating costs alone would compel such developments, as may be realised from the fact that in order to increase its average' rated speed by two knots the great Italian liner Rex had to increase its daily fuel oil consumption from around 700 to 1100 tons of oil. This meant a fuel cost alone of £1000 a day, spent in the work 'of churning up wind and wave around the colossal hull. Current streamline practice in motor cars is somewhat retarded by public hostility toward revolutionary innovations. To this must be added the high economic cost of redesigning machinery and. factories to produce acceptable streamline • models. Nevertheless, a manufacturer here and there is moving toward this end, and, thanks largely to the aeroplane, things are getting better. One of the greatest pioneers of aerodynamics, Gustave Eiffel, none other than the builder of the famous Eiffel Tower, began 20 years ago to study the effects of ,air and wind currents on motor cars, locomotives, railway coaches and primitive aeroplanes. For this purpose he built perhaps the first of those "wind tunnels" which today are scattered all over the world, and from which we have learned so much about how to improve our trans-" portation. Much later the British Admiralty, seeking for the best models to use in constructing airships and submarines, investigated the life habits of numerous aquatic animals, from tunny and salmon grilse to the blue whale. From these studies the fact emerged that the finest examples of natural streamlining were to be found in the last named, and in the shark. fßotli of these, their lines somewhat rearranged, were adopted in experimental motor

The Line Of Least Resistance. ! Streamlining, aeronautical engineers . call it "fairing," is the principal reason > for the swift movement of fish through the water, and adds an important factor • in the swifter flight of birds through ■ the air and, in every instance, the re- . suiting shape takes the line of least resistance in overcoming the .counter- 1 ' resistance of the medium, air or water. ! It does so, moreover, not because of any > mystical purposiveness or other teleolol gical or doctrine of design concepts 5 which man imputes to Nature, but solely j because, as a great biologist, D'Arcy r Wentworth Thompson, has elaborately . shown in his classic monograph-"Growth • and Form," physical laws underlie and . determine all observable phenomena in , the universe. The marvellous structure . of the tuna, which includes fins that t can be drawn smoothly against and 1 partly into its body to gain speed, is no more or less "intelligent" than the weo . of a spider or the hexagonal cells or a, honeycomb, both of which owe thenshapes to the operation of geometow 1 principles, which flow automatically 3 from' the nature of the structural ' problem involved. Among bird? I con- " sider the penguins show streamlining to - a "rent degree. They arc, on account -* of "their form, essentially adapted for • that mode of life in the sea which makes them the most completely marine of all bird« rivalling seals and porpoises in ; their speed. The flippers, as the wings of ppngnins are usually termed, are covered"all over with small scale-like feathers, and are rsed only for swimming the feet being stretched out behind and used to assist in steering. It is curious to reflect that man, who is always in a hurry, should turn for the secret of speed to Nature, who will consume centuries and aeons to complete one of her countless voyages through the worlds of matter, animate or inanimate. But. even in Nature, there is a tendency to finish whatever task is under way with a minimum expenditure of energy, materials and time; this despite the apparent uselessness of the final result. Physicists, thinking of the ways of light, electricity, gravitation, have given this tendency a name, they call it "the principle of soonest arrival." The whole secret of streamlining is in these words. To arrive first, in a world consumed with the passion for speed, travel the shortest route in the briefest time. To do these things efficiently, reduce to its minimum the resistance'of the medium through which you are tin veiling. In other words, back to Nature.