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.
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Defects Revealed by War Service.
It is not an easy matter to generalize on defects revealed by war service. There is not a make of truck that has not developed some weak point of minor or major importance. To cite all these would tend to give the impression that automobile trucks are a hotbed of trouble, whereas few of the defects are applicable to more than one or two makes. For instance, one American worm-driven truck cracked its axle housings; , this was a case of faulty design, and was a particular and not a general defect. A light American truck literally ate up differential drive shafts ; this was traced to poor material. A French chain-drive truck warped its differential casing under heavy, braking stresses. Another had cast timing gears Mounted on bearings of insufficient size. Vibration ensued and the gears were reduced to what the mechanics termed marmalade." A more general complaint was the breakage of canvas and leather universal joints, it being not uncommon to see drive shafts flung across the road during heavy pulling in sand and mud. Spring troubles were fairly general, but in only a few makes did the breakage of a front spring entail the smashing of the crank chamber. In these makes when the frame dropped the base chamber came in contact with the axle. Also, spring failures were almost invariably confined to the front, it being rare for a rear spring to break, even on trucks and cars known to be of poor quality. On trucks this may be attributed to the narrowness of the front wheels ; these would drop into small holes over which the rear tires would ride safely, thus putting additional stresses on the front. Few, if any, trucks on war service had sufficiently heavy front springs. The generally adopted method of attaching the springs to the axle cannot be considered safe. Not one driver in a hundred thinks it necessary to give any attention to his spring clips, yet these have a habit of working loose, and in many cases when an axle has shifted it is practically impossible to steer the vehicle. Frequently the complete breakage of a front spring is to be preferred to the loss of nuts or the breakage of clips. Radiators were a general source of trouble, many a good engine being burned out by reason of small diameter tubes or by brackish water. The honeycomb radiator is not suitable for army truck service. The large diameter verticalsttibe type is most success ful, and is adopted whenever replacements become necessary. It has been found to give good service even when used pn trucks that originally had a honeycomb cooler. Incidentally, it is not safe in the war zone to judge the make of a truck by its radiator. Another good type is the circular tube radiator with a centrifugal fan, as used on the Paris omnibus type of chassis..
Requirements in Engine Design.
Considering a *ton truck as the most suitable type (and of this all who have had experience in the war zone are in agreement) the engine should be a fourCylinder L head of about 450 cubic inch piston displacement. It has already been stated that the under-the-seat position is not suitable except for special service where a maximum body space is required. The underpan is an abomination on an army truck. The base chamber should be easily removable, although unfortunately this shies not necessarily follow when there is no mucipan. The connecting-rod B44 bearings should be detachable, so that it is possible to change them, in case of necessity, without taking the engine out of the frame. A governor is a desirable equipment.
War service has tended to prove the superiority of pump circulation over the therrno-syphon. As a general rule trucks tend to overheat when operating in convoy formation on crowded roads. This condition; only occasionally met with on civilian service, is common on certain portions of the Front, and should be provided for. There are few trucks on which sufficient attention is paid to draining off all the water from radiator, pump and jackets. This is a detail when trucks are housed in a heated garage ; it is an important feature when automobiles remain constantly in the open air, with the possibility that the engines may have to be cranked, to meet an urgent call, at two or three o'clock in the morning.
No man who has had to start an 'engine at daybreak on a frosty morning, with the knowledge that delay meant disaster, is inclined to treat this matter lightly. It is con:in:ion practice for drivera to make straw mats to fit the hood and the radiator, and to use these as heat retainers whenever the truck has to stand idle for a few hours, An additional precaution is to disconnect the gasoline line, empty the float chamber of the carburetter, and leave one of the kerosene side lamps burning under the hood. The manufacturer might help in this direction by making a tightly fitting hood with louvres that could be opened or closed at will, by supplying a heat retaining radiator cover and alsci providing a safety lamp capable of maintaining a certain amount of heat under the hood when the truck is left standing in the open all night. An adjustable air-shutter on the carburetter is a valuable fitment. It is important, too, that the engine should develop something like its full power within a few minutes of starting. In the early days of the war, before men had learned to take precautions, the writer has known convoys to be held up for three or fair hours owing to starting difficulties. A delay of this nature is sometimes fatal.
Mechanical starters are not necessary on army trucks. In the few cases where these have been fitted the batteries have generally been requisitioned to light some dug-out or office. As there are always two drivers on army trucks, iii is hardly necessary to relieve the spare man of the only real work he has to perform.
Radiator Guards for All Trucks.
All army trucks should have radiator guards atta,ched, not to the radiator itself, but to the frame members. The design should be such as not to interfere with free operation of the starting crank. Some guards have been supplied that certainly protected the radiator but caused a bit of finger to be left behind every time the crank had to be swung. The guard should be so designed, too, that it will not allow the overhanging rear of the bo_dy to pass above it. In some cases it has been found advisable to fit a transyerse bumper with coil springs at the Tear of the trucks, this bumper coming in contact with the centre of the radiator guard in case of .a collision. It must be remembered that many of the drivers have had little road experience. The traffic is much more dense than is generally imagined. During the height of the Verdun battle there was a 90-mile circuit over which trucks passed clay and night, for a period of several weeks, at average intervals of 20 seconds
between each vehicle. This means that at times traffic was as dense as it is on lower Broadway during the rush hours.
It has been noticed by officers in charge of army repair depots that engines with the oli-fashioned splash system of lubrication are generally better preserved than those with pressure feed of oil to all bearings. On war service the lubricating oil is apt to remain in service longer than is desirable, and the impurities deposited in the oil are picked up by the pump and forced into the bearings. The remedy seems to be, not a return to splash, but a pressure or circulating system so designed that the dirt will deposit away from the pump. It is really not necessary that the pump should be in the lowest portion of the base chamber. The base chamber can be designed so that the lowest portion is merely a trap for impurities, and this can be done without any danger of the pump being accidentally deprived of oil. Whatever the system, it ought to be an easy matter to dismount the pump and to drain the base chamber of every drop of lubricant. This presupposes the absence of a mudpan. Several American trucks have suffered materially-and in reputation by the absence of a suitable oil. Pressure feed being common in Europe, a heavy oil is generally employed. and this has been used with disastrous results in engines requiring a light bodied oil. The only remedy appears to be for manufacturers to indicate clearly the type of oil to be used on their engines.
Gasolene Only Army Fuel.
So far as the Allied armies are concerned there has been no need to use alternative fuels such as benzoic, alcohol and kerosene, although it was a prewar specification in France that all automobile trucks should operate on benzoic and on a 50-per-cent. mixture of benzole and alcohol. Benzole and alcohol have been monopolized for making explosives, and gasolene has been the only army fuel in use. It is certain, however, that the benzole requirement will be insisted on after the war, and in all probability alcohol will be a widely used fuel. The best place for the fuel tank is on the dash. Pressure tanks at the rear are inconvenient and dangerous. The filler should be of sufficient size to allow a man to pass his hand inside the tank, and there should be easy provision for draining the tank. Drivers in the war zone invariably Garry a. reserve supply of gasolene, this being done because of the feeling of security it imparts rather than because of any urgent necessity for its presence. Suitable provision has not been made, particularly on French and American trucks, for the carrying of this reserve supply. Thus drivers have had to fix up as best they can a storage place for a 12-gallon can of gasolene. Ignition by high-tension magneto has proved all that could be desired for war service, no need having been shown for a second system, either as a reserve or for ease in starting. The only general trouble has been the swelling of the fibre and condensation an the spark plug points, this being due to the excess of moisture in the atmosphere of Northern France. The French military authorities have insisted on the standardization of magneto bases and couplings, and also on all magnetos turning right-handed. The intention, of course, was to make all magnetos interchangeable throughout the army, and although this result has not been obtained, owing to the influx of foreign machines, the system has been good so far as it has been possible to apply it.
There is an amazing lack of uniformity in the steering lock and the turning radius of army trucks. This is most disadvantageous when convoys are composed of different makes of trucks, for while one vehicle can make a turn easily the one following may be unable to do so. The disadvantage is also felt where
makes are grouped, for one convoy may negotiate a difficult road with ease while the next will be stopped. In some makes of trucks the short turning radius is only an illusion, for owing to the radiator extension in front of the. axle it is only possible to turn within the given radius if the road is entirely free. In other cases the radiator is so high that it is impossible for the driver to see directly ahead and take full advantage of his lock. This matter is important, for when a road is under fire the, greater the time spent in making a turn the greater the chance of being hit by a shell.
Only the south-eastern end of the present battle line is in a mountainous district. Thus brakes have not been put to a severe test. Generally there is much room for improvement in the matter of brake adjustment Several cases have been noted of brake rods so close to the road or to the road wheel that they have been bent by a board lying in the road and thrown up at. an acute angle as the wheels passed, over it. Brake rods should be regarded as organs needing protection, and placed in such a position that they are not likely to be damaged by obstacles on the road. Not ninny American trucks are fitted with a aprag, although this is a valuable accessory on military trucks working in convoy formation in hilly country. Picture a closely packed convoy on a greasy hill, trucks without sprags, and a qreen driver in the centre of the column who misses his gears and fails to use his brakes in time.
Four-speed gearboxes are now insisted on by the French military authorities, and are found to be indispensable for active service. First speed should be equivalent to 2 m.p.h. with the engine running at its normal speed (1000 to 1200 r.p.m.). One type of gearbox tha.t.has proved satisfactory under war service is the Darnaizin patent constant mesh gears. This gear set was fitted to the Paris bus chassis, and its use-has been extended to other makes. It is impossible for a driver to muddle his gears, no matter how ignorant he may be of the elementary methods of changing. No experiments have been made with trucks without a differential, but a differential lock, capable of being operated from the driver's seat, if possible,_ is an absolute necessity under many conditions of active service. The only reproach brought against one of the best American trucks on the French front is the absence of this lock.
Operation Off Made Roads.
This naturally leads to the question of operation away from made roads. The greatest objection brought against the automobile truck is the rapid fall of its efficiency as road surfaces deteriorate. The touring car, the ordinary commercial truck applied to war service, and,the various types of four-wheel drive and purely military vehicles are all, in varying degrees, open to improvement in this respect. The general rule is that convoys should keep to made roads and not attempt to operate across country. Officers using touring cars are specifically forbidden to order their drivers to go across country. While this general rule is observed, there are frequent circumstances where the made road practically ceases to be a road, or where the only means to safety lies in a dash across country. The final distribution of food and ammunition under really difficult circum-stances is still effected by horse teams or by men. A two-wheel cart with a half-ton load will get over a road where a. three-ton vehicle, whether drawn by horses or propelled by a gasolene engine, would be in difficulties. If the light cart is hit by a shell the wreckage is easily cleared away and the procession continues ; but a heavy truck disabled on a narrow
dirt road stops all further traffic. , The most Common expedient to render a truck fit to travel away from hard road surfaces is to fit chains to the wheels. These, however, have been far from giving general satisfaction.
(To be con-tinued.)