Charles Stewart Rolls and Edward Shrapnell Smith

“ This fact assisted the British makers to forge ahead in their competition with the French. But the great factor in the triumph of British motor engineering arose from the fact that, in England, there was a great wealth of knowledge concerning the properties of steels and steel alloys, and that knowledge, which was advancing all the time, was turned to such good use that it is safe to say that, in only the very best of French cars is the same strength and efficiency obtained from the same weight of metal as would be used in the construction of quite a number of British cars. ”

“ Vehicles Driven by Internal-Combustion Engines.—The general principles of the Working of a steam engine are better understood than are those of the gas or oil engine, owing to the wide use of the former class of prime mover since the early part of last century, but it is beginning to dawn upon the public at large that the internal-combustion engine, or the “petrol” motor, as it is more popularly termed by those who talk or write about motor vehicles, is even more simple than the steam engine. ”

“ The limitations under which the early steam car laboured have, in the main, disappeared, for the modern steamer can travel nearly as far without requiring to refill the boiler as a petrol car can travel without replenishment of the fuel tank. The electric car is still the luxury to be employed in towns and in covering short distances, for the weight of the accumulators has not been greatly reduced, despite sensational announcements made from time to time.
An interesting feature of the motor movement has been the steady growth in popularity of the motor cycle. ”

“ Any motor-car with an unladen weight in excess of 2 tons is held to be a “heavy motor-car,” and a “trailer” means a vehicle drawn by a heavy motor-car. The expression “axle weight” means the aggregate weight transmitted to the surface of the road or other base whereon the heavy motor-car or the trailer moves or rests by the several wheels attached to that axle when the heavy motor-car or trailer is loaded. ”

“ France is the centre of the motor-car industry in Europe, and up to the year 1906 it undoubtedly led in the production of motor vehicles, but in that year the United States of America, as we shall have occasion to note, took the lead. The number of private cars in use in France had risen from 1438 in 1899 to about 23,000 in the year 1909, whilst industrial vehicles have increased even more rapidly in number. ”

“ But the life of the mechanism of a car, in one form or another, is of considerable length (there were, for instance, in use in 1910, as commercial vehicles, motor chassis that were put on the road in 1896) , and it is considered that many registered but unlicensed cars remain for years capable of rendering useful service in emergencies or on special occasions, such as at election periods. ”

“ The 1903 act raised the speed limit to 20 m. per hour and gave the local government board power to close to motor traffic such roads as, on inquiry, might be deemed unsuited therefor, and to impose a speed limit of 10 m. an hour or less in dangerous places, such as narrow streets in a town or through a village. A few serious accidents in England, and many abroad, have kept alive the fear that the motor-car is a dangerous vehicle that should be restrained or held in check by stringent legislation. ”

“ Lightness of moving parts has led to increased engine efficiency and to economy of fuel, whilst the inert parts of the mechanism—the frame and other fixed details—by being lighter, call for a smaller expenditure of power to overcome their inertia. Apart from the employment of special steels for motor-car construction, in which England took a leading part, many improvements in design and method have originated in Great Britain. ”

“ The vertical type of boiler lends itself admirably to the general design of a steam wagon, because it takes up so little of the total length of the vehicle, whilst the fittings can be mounted in much more accessible positions than are possible with the majority of loco-type boilers. The efficiency is not, however, so high as is the case with the latter type. It may be generally stated that boilers of the vertical class, as used on 5-ton or 6-ton steam wagons, have a total heating surface of about 90 to 95 sq. ”

“ Concurrently with its development into a reliable, silent, odourless and smokeless power-propelled vehicle, the motor-car gradually came into more general use. It no longer appealed only to a few but gained converts daily, and its final triumph came when it began seriously to displace the horsed vehicle. becoming the private carriage of the wealthier classes to be used on all occasions. ”

“ The fact that the motor is separate from the wagon, or trailer, which conveys the load, and can haul a loaded trailer to its destination, leave it, and return with, or for, another loaded trailer, without waiting for the first load to be unshipped, not only makes this class of motor extremely useful to agriculturists and others, but it makes for greater efficiency, in a large number of cases, because the power unit is not allowed to stand idle during the loading or unloading operations. ”

“ Since the passing of the 1903 Motor Car Act, and the coming into force of the 1904 Heavy Motor Car Order, many of the well-known makers of road locomotives have turned their attention to the production of a machine which would come within the prescribed constructional limits, and would meet popular demand. These machines are built on proved traction-engine lines, but with all the parts of suitably reduced size so far as is consistent with strength and the work which the machines are called upon to perform. ”

“ Apart from the improved speed of the motor-cabs, they gained popularity because of the use, on each one of them, of the taximeter, showing at a glance the amount of the fare, thus preventing overcharge on the part of the driver. One effect of the employment of motor-cabs and motor-omnibuses has been to reduce slightly the total number of vehicles, and to quicken a large volume of the traffic; it is now being recognized that to increase the speed of the whole of the traffic of London by about 5 m. an hour is practically equivalent to doubling the width of the whole of the main streets. ”

“ The tubes are exceptionally strong and thick, and, they are made of cold-drawn steel; the water is only forced into them stroke for stroke of the engine. The essential difference between this class of generator and any ordinary motor-wagon boiler, whether of the water-tube or fire-tube patterns, is that the reserve of heat is provided in the mass of the heated tubes, and the rapidity of flame application by the burner, and not in a mass of heated water. The steam, too, is very highly superheated, and necessitates the use of a specially-designed engine with mushroom valves. ”

“ Engine design has undergone unceasing improvement, and constructional methods have been continuously advanced, with the end in view of attaining lightness, not only in the moving parts, but in the inert parts. Lightness in reciprocating parts, such as the pistons, connecting rods and valves, has enormously improved crank-shaft speed. Cylinder castings are now made far lighter, whilst the water jacketing, for dissipating the excess of heat from the cylinder walls, is now of sufficiently ample proportions and, in consequence, better lubrication of the cylinder walls can be maintained. ”

“ Heavy motor-cars fitted with tires of a soft or elastic material may travel at higher rates of speed than if they were not so fitted.
Any motor-car used for trade purposes, but whose unladen weight does not exceed 2 tons, is allowed to travel as fast as 20 m. an hour, and is regarded as an ordinary motor-car. ”

“ The gears provide for two ratios of reduction from engine to road wheels; the higher one is for all ordinary running, and the lower one is for steep hills or for very bad roads. The outer ends of the differential shafts are fitted with chain sprockets, from which the drive is taken to the back wheels by means of chains.
The third type (fig. 9) of steam wagon is particularly businesslike in appearance, and sound in construction and design. It is the outcome of many years’ experience in the design of road locomotives, on the lines of which it is constructed. ”

“ The number of units of heat which can be turned into useful work is very much greater in the case of internal combustion than of external combustion, the efficiency of the petrol engine in this respect being, on the average, about three times as great in practice as is found to be the case with typical steam engines other than those where highly-superheated steam is used, and where the whole of the parts are maintained in the best condition. The amount of petroleum spirit, or of paraffin, required to propel a steam vehicle 1 m. ”

“ Petroleum spirit of 0·700 specific gravity is usually the fuel, but many are now supplied with spirit of 0·760 specific gravity; the range of boiling points is the criterion of satisfactory use—not the density. Petrol vehicles are, practically, stoutly-built motor-cars, and some of the models now in use have been developed from accepted designs of lighter types. There are, however, numerous manufacturers who construct solely for utility purposes. Below net loads of 2 tons, the petrol-propelled vehicle has a virtual monopoly of use in England; above that, it shares the trade with steam. ”

“ The first cost is comparatively low, and such a “steam horse” can be kept constantly at work if there is sufficient demand. A steam tractor is economical and efficient; it can be used on roads where a steam wagon would be impracticable on account of its great axle weight, and, when not used for hauling, it can be put to other work such as driving pumps or builders’ machinery, or for a host of other purposes requiring a portable power installation. ”

“ From the last change-speed shaft the power must be transmitted to the road wheels through a differential gear and through one or other of the types of final drive which are now employed by representative makers. The great distinction from the axle of a horse-drawn vehicle is that there must be both a mechanical connexion, yet a differential action, between the two back wheels. ”

“ The aim has been to secure definite lubrication of all moving parts, and, at the same time, to prevent oil being present on the cylinder walls in such quantities as will permit the piston to carry it up into the combustion chamber. Any oil present in the combustion chamber is burnt during the explosion, but, its combustion being imperfect, smokiness of the exhaust is the result. By reducing the oil on the cylinder walls to the minimum necessary for lubrication, smoking has been abolished, whilst clogging, or carbonizing, of the valves has been materially reduced. ”

“ Police traps, or measured distances, over which the motor-car is timed by the police, were established in most of the counties of England, and, whilst, without a doubt, many real offenders were caught, it is equally true that many an innocent driver was unfairly accused, whilst motorists guilty merely of technical infringements of the law were summoned. ”

“ The carburetter is a vessel in which the liquid fuel is converted into a combustible gas or Vapour, for, as there is no Connexion to any gas main, the ordinary petrol engine has to make its gas “on the premises.” The production of the gas is automatic, and calls for practically no attention from the driver, because, once the engine is started, the necessary aspiration to draw through the correct quantities of air and fuel is provided by the action of the valves and pistons. ”

“ A fan is generally employed, either situated behind the radiator and driven by the engine, or the flywheel is vaned so as to induce a current of air through the radiator. To deal now with the transmission mechanism, the drive is taken through a clutch and gear-box as in the earliest days, but, for the final drive, chain transmission to the road wheels running on a fixed axle has largely given place to propeller drive on to a live axle. ”

“ A small electrical storage battery forms part of the system, and this receives the excess of current from the dynamotors when the whole power of the engine is not required for the propulsion of the vehicle. When the machine is being driven up a steep incline, or when it is required to travel in a reverse direction, the battery may be called upon to supply current to the dynamotor, and, in this manner, the power of the engine is augmented by the dynamotors’ working as electric motors. ”

“ Every detail has been improved so that the cars are more efficient, easier to control and manage, and infinitely more comfortable, but, in essence, Levassor’s scheme is as good to-day as it was when planned by him. ”

“ As a large gear reduction is thus rendered possible on the back axle, it will readily be understood that the change-speed gear-box may be made considerably smaller than would be necessary for a bevel-driven live axle, where a large gear reduction is not permissible, both on account of its size and because such a gear would be very noisy in its working. ”

“ In the nine years that immediately followed French manufacturers spent large sums of money in experimenting with and developing the motor-car, and by 1896, when the Enabling Act was passed, there were a few practical vehicles in England but, perhaps, fewer probable buyers. British makers, starting as they did in the wake of the French manufacturers, were able to profit by the experience gained by the latter, and thus to avoid many otherwise inevitable mistakes ”

“ The gear drive offers advantages which, for heavy loads, are not offered by any other form of drive.
The features which are common to all steam wagons of the second of these types are: vertical fire-tube or water-tube boiler; horizontal compound engine; two-speed gear; differential countershaft; and two sprockets which transmit the final drive, through chains, to the rear road wheels. The exact form which the boiler takes is a point which has considerably exercised the ingenuity of individual designers, in order to arrive at one that can be cheaply produced,
Fig. ”

“ A single lever is usually employed for engaging any of the forward gears or the reverse, so that the mistake of simultaneously engaging a reverse and a forward gear is not possible. The spur-wheels are generally mounted in pairs on two sleeves, so that, by means of a selector mechanism that compels one sleeve to be brought to the neutral position before the other can be moved, no two gears can ever be engaged together. ”