THE MOTOR

Evening Post, Volume CIII, Issue 55, 7 March 1922, Page 10

THE MOTOR

A HARVEST OF IDEAS

THE MULTI-WHEELED MOTOR

(By "Autos.")

The war was, like necessity, a (treat mother of invention, and the ingenuity of man, devoted during that period to tho creation of now engines of destruction, and to defences against them, is now obviously* turning to the twentieth century process of making spears into ploughshares and swords into reaping hooks. There' wa3 nothing specially original in tho vehicles employed in mechanical transport during tho actual war—they were just, for tho most part, peace-time care and lorries—and even the tank was but a simple development of the Holt tractor used for ploughing t no prairies of tho great Wost of America. Quantity was needed rather than quality, and such wore tho losses of material that there was usually no time to replace it except with standardised facsimilies. Only in aeroplanes and tanks was there radical progress, and even there the need for mass production forbade experiments, completely changing any existing device. It was chiefly iv detail that alterations were made, and only an expert could detect the real differences between tho aeroplanes of the first and last years of the war.

Al] tho time, however, the tremendous stimulus to invention continued, and, when the war suddenly ended, there were many novel devices in preparation. The year of the Armistice and tho following year—l9l9 and 1920—wore times when tho demand, ' for motors especially, was so great that experience could hardly be embodied fully in tha supply. Experiment had to wait on production instead of vicey<?r.?a. Now, however, with the slackening of demand last year, inventors have had time to think again and experimented to experiment. It has been a period of ■silent growth, and now there as appearing above the 6iirface a crop of ideas in every direction.' Ona lias only to look at tho English and' American motor journals of recent dato to realise tho fertility of invention and tho attack made by novelty on the orthodox.

Take, for instance, the multi-wheeled car or lorry—the vehicle with more than four wools. The motor (an English publication) has devoted pages to the exploitation of this idea of carying the weight on more than two axles, and there are, to the orthodox layman, a host of fantastio drawings of six and even oight-wheelera running to the extent of a perfect motor train. One actual example is illustrated —the Mustad, a Norwegian six-wheel car with the drive on the four-wheels situ, ated, liko a locomotive bogio, in the rear. A ten-wheel devico by an Australian engineer, Mr. de Mole,, is also described, and a variety of arrangement of the wheels is discussed in successive articles , running well into tho New Year. The Motor sug. goats that England, by this new idea, realised in actuality, may regain some of her lost overseas markets.

The idea is worth examining. In Wellington there are already "two or three srix-wheel lorries—notably one used by the Wellington Gas Company for transport to and ..from Miromar, and certainly the- loads, carried se,em . exceptionally large. The. vehicle is. quite simple—a short base tractor with drive on the second and inside pair of wheels, with a lorry part behind attached by a yoke coupling, so that the rear wheels' gener-' ally follow the track of the. front part. How-reversing is managed the "writer Hoes not know. Then, in the country districts particularly in flat country,, like the Wairarapa, the Manawatu, the : Taranaki plains, and the Wair&u Valley round Blenheim, the ordinary trailer is widely employed carryin .a. useful load. The advantages of a multi-wheeled vehicle are obvious. The chief advantage is that of the distribution of weight. A five-ton lorry running on four wheels will sometimes weigh with load as much as twelve tons, and regularly anywhere from eight to ten tons. Of this load, probably the rear axle will carry fully twothirds of the weight—say six to eight tons: What ordinary road or bridge can stand up. for long under such axle loads' carried on solid tires at a speed of twelve miles an hour? Even concrete would crack up under it in no longer time. As for the "ordinary macadam road, its' life under heavy traffic of this kind is literally limited to months. How often during the past two years has Thbrndon-quay, or Crawford-road over to the eastern suburbs, been repaired?; What' is the state to-day of the Hutt-road or the road through the Ngahauranga Gorge? What is the state of .the boasted American concrete roads, say, in California? One remedy suggested, of course, is the Giant pneumatio tire inflated to over 1001b pressure per square inch. But , will the pneumatic carry the eight-ton axle load, and what happens incase of a puncture? More wheels mean a sub-division of the axle load, and by this means the weight on the road can be reduced to reasonable proportions,- and pneumatics can be safely employed. In Akron, Ohio, the home of the American tire and rubber industry, a* huge motor 'bus, something like a railway car, has been tried out successfully, ..with. six wheels running on penumaties. Exhaustive teats showed that the impact per ton load on the road in the case of this vehicle -'-an eight-tohner—amounted to only 3001b as compared with 10,9501b per ton load for a, two-ton four-wheeler on solid tires. Six of these six-wheel vehicles have already been built rand covered an aggregate of 60,000 miles severe testing, including a journey, across the American Continent from Los Angeles to New York at an average speed of 21.9 miles ■ p»r. hour. The cost is only about £100 more than that of the normal five-ton vehicle.

There it on« further point. The six or eight-wheeler distributes the load longitudinally along the. road, but laterally considered, the .'oad is still carried on two strips of road which tend in the long run, to become ruts. Wherever limitations in the width of a road occur, traffic inevitably follows tracks, lik» .railway lines. If roads ;were reinforced like railway lines to carry the load on th*se two parallel stripe, then all would be well. In Borne parts of the heart of the industrial North of England, where the traffic has been extremely heavy for a century, steel channel plates ' were actually laid down for the cart wheels, in the days of' horses, to run in, .while tho horse plodded along the ■ stone sets' in between. But a horse, lorry is drawn, not driven, and the action of the driving wheels-of heavy motors is far .more destructive to any ordinary road. Imagines electric trams, weighing 40 odd tons, running without rails, and the effect will bo realised. The logical conclusion then is that the load of road traffic, pur© and simple, should bo distributed crosswise as well as-lengthwise. ■ During AHenby's Palestine campaigns, between' the ' fall of' Gaza and the final battle, an army of about a quarter of a million 1 men was supplied from the 'buses ,for many montli9 by mechanical transport, while railways were, being pushed .ahead. The great road tell was between 'March and September, 1918, throughout the dry summer. Three hundred lorries used ..to run daily from Latron to Jerusalem over a road that necessitated keeping much to the same track. The result was that not an army of labour and hundreds of tons of road metal could keep the road in., proper repair. It was pounded to pieces by the long convoys of lorries strung out like a train, following in each ■othev's tracks, from the coastal plains to the Holy City. Army Headquarters issued instructions that lorries must not follow each other's tracks, and road engineers actually put boulders in the ruts to keep the vehicles out of them; speed was reduced to a maximum of six miles an hour under penalties, but the destruction still went on. The writer, who went through it all, came to the following conclusions:—As roads are built of an even thickness of metal across—perhaps a little thicker in the centre —there is no natural provision to carry • the whole load of traffic in two- parallel strips, on which at present, with two-track vehicles, tho burden inevitably fails. Tho load should,

therefore, be distributed laterally, as well as longitudinally; that is, no two pairs of wheels should run in the same track. Hence the suggestion was made of • a live-wheel motor vehicle with a single leading wheel, then two driving wheels talcing the widest track, and a pair of trailing wheels taking a ti-ack in between tlio single front wheel and the two drivers. Steering would be by the front wheel and the two rear wheels, and the vehicle would run on five tracks instead of two. If the idea does not commend itself to motorists, it is probibly because Ihoy are accustomed to ronds with ruts in them, and because they keep in those nits. But let them assume a new road, fresh from the roller and without ruts. It is clear, then, that a five-track vehicle, with the load distributed over five tracks across a width of five to six feet—according to weight and size of vehicle—would scarcely in any amount of running make ruts-. If all vehicles wore built the same way, tho wear and tear of the road would bo distributed over its whole surface, and its Jife would bs correspondingly longer. At present, tho contact of wheel and road is like the battle between gun and armour, instead of a friendly co-operation, and so far the wheel has had tho best of it, though the road gets' it back in prematurely outworn tires, broken springs, injbred transmission, and poor mileage, when once tho wheel has done its fell work. These are days for experiment,' and nothing should be regarded as perfect, final, and complete, least of all the motor, when its life is a modest five or six yoars, and the life of the road it runs on far shorter still. The writer's idea was put before the War Office, but the war finished a fe^v months later, whilo railways took the heaviest traffic over tho roads of Palestine. But for thin-skinned roads like ours here, it may still have merits. . .