The Development of the Steam Wagon,
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Steam wagons may come and go, but it must be evident to everyone interested that the most popular at the present time is the type introduced by Mann and improved upon by Foden. [Is our contributor correct here ?—En.] This type has been copied by many makers, and it is being produced by all of them for the home and foreign markets. When Mann first introduced his wagon, it was evident that he had taken a small traction engine and had placed his boiler and engine in front of a cart body and axle, connecting the axle by gearing to the crankshaft of a small traction engine. Foden's public debut was made at the War Office Trials in December, 1901, when, although his consumption was low, he had to meet the serious objection of being handicapped in the use of a driver and fireman, as compared with the winner, the Thornycroft, controlled by one man alone. However this may be, it will be of interest to trace the origin of this popular (at the present) type of road wagon, and to see how the experience gained in the early days of the portable steam engine and road locomotive has survived all through the period of severe competition comprised in the early struggles of the road locomotive between the years 1356 and 1896.
From the journal of the Royal Agricultural Society of England, Vol. XVIII, S.S., Part I, I extract the following, and it is aa.i extract throwing interesting light on the birth of really the present popular form of steam wagon. The article describes the life of the late Thomas Aveling, and states:—' In his now proper business, he scored his first public success by giving self-propulsion to the portable engine. The anomaly of a steam engine being drawn to the site of its work by six horses, he compared to six sailing vessels towing a steamer,' and pronounced, in his characteristic and energetic way, the arrangement as an insult to mechanical science.' "
In 1859, Aveling took out his first patent to overcome this defect ; he exhibited an engine constructed on his own principle at the Royal Agricultural Society's Show at Canterbury, in 1860, together with several other agricultural implements, all made by other manufacturers, thus showing that then, although an inventor, he had not become a maker. He was, in fact, an improving dealer, and not what in after years he was fond of calling himself—a "blacksmith." The catalogue of his Canterbury ex
hibits was headed by a description of an 8 patent locomotive engine, invented -by the exhibitor, manufactured by Clayton and Shuttleworth and Co.,
Lincoln, and " fitted with the exhibitor's patent arrangement for locomotion and steerage, by which the whole set of machinery may be moved from farm to farm without horses."
The report of the judges of implements at that meeting contains the following notice of his stand :— " Thomas Aveling's stand of steam-engines, threshing machines, elevators, horse gearing, and other machinery, met our very high approval ; his universal safety joint to his driving shafts is worthy of extensive patronage." Although very encouraging to a beginner, it is noteworthy that Mr. Aveling's first attempt to bring into notice a self-moving engine for agricultural purposes was passed over on that occasion without mention by the judges. The accompanying sketches will show the development and the improvements made in the road locomotive first introduced in 1857-60, and the gradual steps and changes that were made in the designs from the self-moving portable, steered by a horse, to the present popular form of steam wagon. All the various changes and alterations appear to us very obvious and natural in the present day, but we may rest assured that each change shown was only made after very serious consideration, and with the certainty that a practical advantage would be obtained from the improvement introduced.
Fig. 1 shows a modification of an early standard portable engine. The cylinder over the fire-box allowed the flywheel driving belt to be clear of all obstructions. Usually, this engine was hauled from farm to farm by four or six horses, the boiler, of course, being emptied for lightness and ease of draught. Nothing could be more simple than to reduce the number of horses to one, and that one only for the purpose of steering, and to connect the crankshaft of the engine to the hind axle of the portable engine, by means of a chain. The portable engine, with the assistance of the one horse in the shafts, then became self-moving, and could be driven to the farm where the thrashing tackle was last working.
However, it was evident from the Canterbury Show that nobody foresaw that, in this embryo, was the beginning of all the main features and improvements used by steam road engines of the present day. Did the patentee and manufacturer find himself overwhelmed with orders ? Of course not ; he had not only to preach the obvious, but get the countryside accustomed to such monstrosities on the road. He, however, had one advantage, owning thrashing sets as he did, he was enabled to cut out competitors by
promising the farmer that he could reach his working place with the aid of but one horse instead of four. But he had yet many difficulties to overcome : his thrashing machine still required horses ; and his converted portable engine had no accommodation for water or tuel. Moreover, to an inventor of his type, the need for even one horse must have caused him to lay awake at nights considering how he could do without it.
Fig. 2 shows an improved type of thrashing and hauling engine introduced about 1850-60. The horse, seen in Fig. 1, was useless as a motive power, acting, as it did, solely for the purpose of directing the front axle, and thus steering the locomotive in the direction required ; the horse, however, had this advantage over its displacer—the front axle could be directed when the engine was stationary.
But, in addition to the superseding of the horse for steering purposes, the engine on the top of the boiler was reversed, the cylinder being placed at the smokebox end of boiler and the crankshaft over the fire-box. The cylinder was steam jacketed, and both steam dome and cylinder were combined. The driving chain, by this design, was shortened, and this alteration proved to 'be the foundation of one of the most important improvements since road engines were introduced, i.e., the extension of the fire-box sides. forwards, upwards and backwards, to take the brackets for the steering barrel, crankshaft, intermediate shaft and back axle, as may be seen in Figs. 3 and 4.
The pilot wheel used for steerage was first in troduced by Mr. Worby Beaumont's grandfather, for the purpose of steering agricultural implements. and Aveling immediately adopted it, with, I believe, Mr. Worby's permission. Fig. 3 was now the adopted type of road locomotive, and the position of the steersman in front of the smoke box was always an anxious one when heavy loads had to be shifted. The natural inclination of a road locomotive when it has got hold of a load, somewhat beyond its power, is to lift the front axle. When this type of engine was fairly put to a load, and the regulator was opened, the road locomotive would take the load with a spring, up would go the front axle, and the steersman, if he were not ready, would be catapulted off his seat in front of the smoke-box. Someone asked Mr. Aveling to tell him, in those days, what really was the first thing that gave trouble with a road locomotive ; Mr. Aveling, after a promise of secrecy on the part of the inquirer, gave one of his usual and concise replies, and answered, "Everything.'' The extended boiler fire-box side was immediately imitated, and, to avoid infringing the patent, one manufacturer extended the fire-box side for a matter of a few inches, and then connected his gear brackets to the extension ; this was claimed to be an infringement, and the case taken to the courts, but was held not to be an infringement of " Aveling's Patent." In Fig. 4 is shown the present form of road locomotive, the parent of the present form of the mostpopular type of steam wagon. The driving chain was done away with, and the steering effected by means of chains from the front axle to a steering shaft under the barrel of the boiler, and the chain shaft was controlled by a worm and wheel, which could be controlled by the driver or his mate.
The speed gear was not overhung, but was carried inside the horn-plates ; much was made of this point, although, when the compound type of engine was introduced, this main feature had to go. To show, however, how much this improvement was appreciated, Messrs. Clayton and Shuttleworth, only a few years ago, patented an arrangement to enable them to retain the feature with compound engines.
There can be no doubt that the present form of steam wagon owes its success to the adoption of the principles laid down by the early pioneers of the road locomotive, since these old engines did their work, and were robbed of every excrescence and unnecessary accessory, running, as they did, without any spring mountings whatever. But further than this, no credit could be given to the early road-locomotive men, since the problem of carrying a load is very much harder than that of drawing one, and a tractor is not so easily abused as is a steam wagon. A steam wagon will generally move and carry any load up to eight or 10 tons, if the body is large enough, which load might be double the load for which the wagon was constructed ; not so, however, with the road locomotive or tractor, as when the load is too great or the roads too heavy, the tractor simply fails to haul the load.
have now shown how the present form of steam wagon has developed from the early days of the portable engines, but the main improvement which made this application possible must be put down to the enormous strides made by the makers and designers of high-speed and powerful driving chains. To summarize the advantages of the locomotive type of steam wagon ; the boiler is of the ordinary locomotive type ; the cylinders are steam jacketed and are placed on the top of the boiler ; the jacket forms with the steam chest a steam dome ; the communication between boiler and engine is direct, thus preventing condensation ; the link motion and gear is within sight and touch of the driver ; the steerage is of the simple road-locomotive type ; the latest improvement is the introduction of the Belpaire type of fire-box, in which the water space on the top of the fire-box is increased, and the steam, instead of being taken from the barrel of the boiler at the smoke-box end, is taken from the top of the enlarged area over the fire-box, thus obtaining steam of a higher temperature. and doing away with the bridge stays over the top of the fire-box and providing a more-easily cleansed fire-box top, by the substitution of screwed stays in the place of bridge bars.