Automobile Experiences in the Great War.
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A Paper Contributed to the American Society of Automobile Engineers by W. F. Bradley, Our Special Correspondent in Paris.
Foreword.
The author outlines the constructions that have shown up well under war conditions of operation, mentioning especially that four-cylinder engines carried under a hood were the most satisfactory. The internalcombustion engine had found • favour as compared with the gasoline-electric and steam-driven vehicles. The defects revealed by war service are given in considerable detail, the author finding that all of the trucks used had developed some weak point. Radiators and springs were given as a general source of trouble. The author believes more attention should be paid to the draining off of water from radiator, pump and jackets. The lubricating system for the engines should be of the pressure or circulating type so designed that the dirt will deposit away from the pumps. He outlines a number of operating troubles developed under the existing conditions of operation, and gives •examples of the way these have been remedied.
Considerable attention is paid to the methods of operating trucks away from made roads. The methods of fitting chains to the wheels,, and the use of caterpillar attachments are .described. All-metal wheels are being used in place of the wood wheels. Considerable tire trouble has developed ; one reason being the tendency for the cambered roads to force one of the dual tires to carry the greater proportion of the load. Dimensions are given for bodies and a number of suggestions made as to their proper construction.
Although practically all the general transpoatation is done by rear-driven trucks the four-wheel2driven vehicle is used to a limited extent, mainly for opera, tion off the main roads or on no roads at all. A description is given of tractors developed for this service. These are used mainly to draw batteries and heavy artillery. The importance of-the armoured car hasbeen exaggerated mainly because of the adoption of underground warfare. The author describes briefly the most suitable type of such a machine. One effect of the war has been to bring about the extensive use of trailers, the author stating that they are now being used behind all kinds of automobiles, both for the transportation of men working in the rear of the lines and for general haulage work around the depots.
In conclusion, the paper considers the asguments found in the war zone in favour of .standardization. The author holds that such a tendency should be opposed as regards the general features of auto"naoblIe design. Certain features that can be adopted without handicapping the design should, -however, be insisted upon. He gives specifically the size and style of bodies, sizes of wheels and tires, magneto bases and couplings, carburetter flanges, towing hooks, turning radius, clearances, driving chains, and threads for all bolts and nuts as subjects for standardization. He also mentions the necessity for uniJorm nomenclatuae, inasmuch asAt-gree, deal of confusion has been created by the difference in the names of American trucks, not to mention the trouble caused by the variation in English and French terms.
60,000 Warroobiles.
Although a tempting subject, and one on which comparatively little reliable information has been published, it is not intended in-this paper to detail all the uses to which automobiles are being put in this war. On the Allied Front in France, from the North Sea to the Swiss frontier, there are, no doubt, 60,000 army automobiles of all kinds. It is known, 052
too, that there are 24,000 American trucks in sertice with the Allies.
Before August, 1914, it was realized that automobiles would play a prominent role if the nations of Europe went to war. In the annual manceuvres sonic nations had gone so far as to abolish the use of horses in the supplying of food and ammunition to an entire army corps, and had found the experiment to be successful. But no single expert, either military or automobile, appears to have foreseen the extensive use of automobiles to be developed within a month of the outbreak of war. In all their preparations, it is certain that the war authorities had never contemplated having_ to go outside Europe for their supply of automobiles. This contingency was so little foreseen that it is doubtful if the military automobile authorities of France and England could have named the six leading automobile truck makers in the United States, or if any of them could have given, from memory, the characteristics of a leading American truck.
Yet the war had not been in progress more than a month before France, the nation that had most carefully studied the use of automobiles in war, had sent an official to the United States with instructions to buy several thousand trucks ; England, with a greater number of commercial vehicles than any other nation, was also anxious to supplement her military fleet with trucks from across. the Atlantic. The trucks available were ordinary commercial vehicles, built for commercial conditions in the United States, without their designers or manufacturers ever having conceived that they might some day be employed in war service. These purely commercial trucks were put to work side by side with the more specialized European machines, and although they were all open to improvement, in some or many respects, they all gave—and are still giving—good service in the war zone.
From this it must not be assumed that any ordinary truck is fit for war work, that there are no special military requirements, and that no lessons have been learned during nearly two years of war. The point to be enforced is the uselessness of trying to develop a special type of automobile truck to meet purely military requirements, without any consideration of commercial service. The proportion of automobiles attached to European armies will never again fall as low as it was, prior to August, 1914. Of necessity a certain number of purely military automobiles will differ from the commercial truck as much as a battleship differs from a cargo boat ; but the great bulk of the automobile trucks for any future war will he the commercial trucks of the nations involved. When the whole weight of the nations' resources had to be thrown into the scale, the military authorities had to take the type of vehicle in general use and forget as quickly as possible all their carefully prepared specifications and all their imaginary essentials.
Part Played by Subsidy Vehicles.
Before the war the British authorities had designed a subsidy type of truck. Admittedly a good vehicle for military purposes, it had been designed with such disdain of commercial service that few business houses would purchase it. When England went to war less than 50 of these army subsidy trucks were to be found in the whole of Great Britain. Then the requisition officers gathered in practically everything on wheels. It was a jump from one extreme to the other, for many of these hastily requisitioned trucks never got within sound of the guns.
The French system was much less drastic. The military authorities, instead of saying dogmatically what were and what were not good features oftariny truck design, left these matters largely to the engineer and were content principally with imposing working conditions. If a truck could fulfil those conditions, it would be accepted as an army subsidy vehicle, no matter whether it had worm or chain drive, whether its motive power was obtained from steam, gasolene, electricity, or from a combination of these. In the end this tended towards uniformity, for it automatically eliminated unsuitable types. But it did not bar a manufacturer who failed to see eye to eye with the military expert on the question of final drive, or who refused to give up his preference for a particular type of wheel bearing or gearbox. The problem was, and ever will be, one of directing design into such channels that the whole of the nation's commercial trucks could be applied to purposes -of war. This application must be possible, however, without interfering with the primary usefulness of the trucks as commercial vehicles. It is a matter of compromise. If the truck is highly specialized for some class of commercial work, it will probably not be of great value on war duty ; if it is designed only to meet military requirements, the ordinary customer will refuse to buy it, either with or without the offer of a subsidy.
For instance, in France it was considered that the. most suitable military type was a two-ton truck. But the commercial user was not satisfied with a two. tonner, and would have preferred a vehicle with a five-ton load capacity. Thus a compromise was struck with 3-!;§ tons, and it is this capacity of truck that has proved the most suitable under actual war conditions. It is not so light as to be constantly. threatened with overloading ; it is capable of hauling one or more trailers ; and its dead weight is sufficiently low to enable it to operate over poor road surfaces. For general conditions of war service the five-ton truck has too great a dead weight.
For certain special classes of work it has been found that a four-ton truck gives the most efficient service. This model has not been produced in great quantities in Europe, and, curiously, is not found in America. Manufacturers in the United States have specialized on three-ton models, but have not produced any intermediary model between this and the five-ton truck, The demand for a four-tonner is comparatively recent ; it does not alter the general statement that. the bulk of, the work is bestdone by the V---ton vehicles.
Light weight, consistent with strength, has been shown to be essential. The French truck, as it had been developed up to the eve of war, had to weigh not more than 33., tons (7716 lb.), this including the entire truck with its body, water, gasolene, oil and hoop.s capable of receiving; a suspended load of 2645 lb. In reality the weight was nearly always below the maximum, some of the trucks scaling as low as 5730 lb., and the average being just under 6200 lb. The tendency since the war has. been toward a further reduction in weight. Such bodies are of the platform type with movable sides and detachable canvas top on reinforced hoops, the hoops being used to carry a portion of the load—generally wounded men.
Pour.cylinder Engines Satisfactory.
Four-cylinder engines are insisted on, and these have been found quite sufficient for all ordinary purposes_ Some of the heavy tractor engines have six cylinders, but their number is small. The French military authorities have never made any attempt to impose cylinder dimensions. It was in the interests of"the manufacturers to get the smallest engines capable of doing the work, for fuel consumption was taken into consideration. The small engines of two or three years ago have' however, been found unsatisfactory. Moreover, the requirement that each truck should be capable of hauling a fully loaded companion up a macadamized eight-per-cent. gradient has tended toward a slight increase in piston displacements, and also toward certain modifications in gear ratios. Statistics of la different makes of French army type trucks that went into service August, 1914, show that the average bore was 3.9. in. and the average stroke 5.7 in. The biggest engine measured 3.9 by 6.69 in. and the smallest 3.5 by 5.5 in. bore and stroke, respectively.
All engines are carried under a hood. There has been a tendency towards this for several years; but the war has shown its advantage over the under-theseat position so clearly that the latter will no longer be accepted. There are a few exceptions, which only tend to prove the rule, notable among them being the Paris omnibus type of chassis. These vehicles, however, are used exclusively for carrying troops. On such work the. greatest possible body area is required. In passing, it may be mentioned that the internalcombustion engine has proved itself without a rival for military transportation. No gasolene-electric systems have made good. The tendency is toward a reduction in the number of steamers. Even the British, who have always shown a partiality toward steam, are making comparatively little of it in France, although steam tractors and wagons are much in evidence around the camps in England.
Many Types of Final Drive.
Under the French military regulations every type of final drive was admitted-; the English military subsidy specification called for a special drive. Those partisans who,.looked to the war to settle the question of final drive are .likely to be disappointed. At present automobile trucks,are in service on the Front with -straight bevel drive, double reduction bevel, worm, internal gears, and side chains, with and withcut housings. No one type has shown itself incontestably superior to all the others, and so far as it is possible to estimate their opinion, thehigher authorities have no intention of imposing the adoption of any particular type of final drive. The automobile department of the -French Army has carefully compiled statistics dealing, with parts supplied to trucks in service, but it is likely they will be used only to determine the makes that have been most economical and satisfactory, and not which type of " design is superior. These data are closely guarded, and even if given out would be useless without explanations. One poorly built make of trilak would be quite sufficient, for instance, to discredit a particular type of final drive if statistics were examined without a complete understanding of them.
While the question of final drive will remain unsolved by the war, it being, left to commercial users
to work out thistproblem, the writer is of the opinion that chain drive will gradually disappear before
worm, internal gear, and double reduction, bevel axles. This is not intended to infer that the chain has given more trouble than its rivals. It is repre sented in the French Army by White, Packard, Ber net, element-Bayard. Rfletet-Schneider, Saurer, F.I.A.T. and Delahaye trucks. These makes have given as good service as any others, but the impres
Sian remains, and is probably correct, that the chain is less mechanically. •Acient. when new, than some
'other types of drive ; its efficiency is certainly less under some conditions of operation. The ease with which the chain can be repaired or replaced is art
asset in its fgtvaur ; but the claim of high clearance is open to question. Under certain conditions cf onera,tion unprotected side chains constantly plough through a bed of mud, and although they can get -through it is at the cost of the chains.
(To be continued.)