Early Subsidy Schemes—Amount of Subsidy—Standardisation of Driving Control—Important Mechanical Features—Provision for Working in Convoy—The “Chain-Drive” Controversy—The Present Position.
In view of the peculiarly advantageous circumstances detailed in the previous chapter, the British subsidy scheme is from the pecuniary point of view less imposing, and from the practical point of view far more comprehensive than any other scheme yet attempted elsewhere. The British War Department favours in general the use of vehicles intended to carry in active service useful loads of about three tons, but as the machines also have to take four men and a considerable quantity of kit and stores, they correspond to ordinary industrial vehicles of four tons capacity. There is a parallel, but much smaller, requirement, for 30-cwt. vehicles corresponding to the ordinary commercial two tonner and capable of higher speeds than are desirable with heavier machines. These lighter cars are intended for use behind mobile and fast-moving troops, while the heavier type are for the service of the infantry, and for the carriage of ammunition supplies. In each case, the total amount of subsidy paid is from £110 to £120. A portion of this takes the form of a cash payment when the vehicle is accepted, while the remainder is an annual payment spread over a period of three years, and is conditional on periodical inspection revealing the satisfactory condition of the machine subsidised.
The agreement also provides that in the event of the War Department desiring to commandeer the vehicle in time of war, a very liberal price shall be paid to the owner, this price being of course dependent to some extent on the age of the machine. The correct amount is arrived at by deducting from the first cost of the car a certain regular percentage intended to represent the depreciation in value during every half year of normal service. After this deduction has been made, the resulting figure is increased by an agreed percentage of itself, the final result being that the price paid for any car under about two years old is very near, if not quite equal, to the original first cost.
The first move made in the direction of a subsidy scheme in Great Britain dates back to 1908. At that time it was believed that light steam tractors best filled military requirements, and a number of these were registered, the nominal payment of £2 per annum being made to their owners. The industrial petrol vehicle was at this time passing out of its period of probation, and it was not long before the military authorities came to the conclusion that it represented a more useful type, in view of the nature of the particular emergencies against which they were chiefly called upon to guard. The ordinary steam-propelled vehicle was open to certain objections, the principle of which is the fact that its carrying capacity of fuel and water is limited, and the latter must necessarily be replenished at fairly frequent intervals. This is no great drawback in commercial work, but might be a very serious matter indeed in times of war, when men and horses have a prior claim on a possibly limited water supply.
In 1911 a scheme of subsidy for transport and supply motors was authorised, and in view of the fact that no such scheme could be matured until it had been in force for several years, a provisional scheme was temporarily adopted, under which total sums ranging from £38 to £52 were paid to owners of vehicles generally of about three tons capacity. The present subsidy scheme was finally put into force in 1912 after the War Office experts had conferred on many occasions with representatives of the leading manufacturing interests. The main objects of the scheme are plainly stated in the War Office specification as follows:
As to the first of these two stipulations, one would think that there could hardly be two opinions, though in point of fact it has been argued in some quarters that no standardisation of driving control is in any way essential. Such a view one imagines can only be held by those who are personally so fortunate as to have that mechanical knack which allows a man to take charge of any car, however different it may be from those to which he has been previously accustomed, and to drive it with perfect safety and efficiency even at night-time and over unknown and bad roads. We cannot assume that every transport driver possesses this instinct, and we must therefore agree that the object aimed at by the War Department is one which deserves every support. It is, in fact, worth while to go into a little detail on this point, in order to show what care has been taken to make everything as easy as possible for the driver.
First, as regards the hand control. The steering wheel must provide for 76° of movement of the front wheels of the car; that is to say, 38° of lock from the normal position on either side. In reaching the maximum lock, two complete turns of the steering wheel must be made. Thus, a driver who is used to getting a certain effect by turning his wheel through a certain distance, will find if he is put on to a subsidy car of another make that the same effect is still produced by the same amount of movement. This, of course, helps to make him immediately a safe driver in traffic or at sharp corners. The four-speed change-speed gear is operated by means of a lever in a gate. This gate must be formed of two slots and two selectors, the reverse being a continuation of the first speed slot. The hand-brake lever must be arranged to push on, and must be well away from the change-speed lever and to the right of it. Furthermore, the brake lever must be 6 inches longer, and must have a plain cylindrical handle, whereas the change-speed lever is finished off with a circular knob. Thus, any confusion between these two levers in sudden emergency, or in the dark, is completely prevented. The throttle and ignition levers must be placed underneath and to the right of the steering wheel, their movement being independent of any movement of the steering column. Increased engine speed must in each case be produced by moving the levers forward. The total movement must be 90°, and the handles must be at right angles to the main axis of the vehicle when in the centre of their travel. This, again, means that a driver who is accustomed to producing a given effect upon his engine by a given movement of the ignition or throttle is in no way confused by being put on to a different car. The only point in which any variation in driving control is permitted is in regard to the accelerator pedal, the presence of which is optional. However, if a foot accelerator is provided, it must be so combined with the hand throttle that on releasing the accelerator, the throttle valve returns to the position set by the hand lever. The clutch- and foot-brake pedals are marked C. and B. respectively, and the clutch pedal must be on the left, the brake pedal on the right, the travel in each case being about 3-1/2 inches. From these details it will be seen how carefully every item in the driving control has been considered, with a view to facilitating the work of drivers who may have to be moved frequently from one machine to another. As to whether the arrangement adopted is a good one, we have strong evidence of a favourable character in the statement of Mr. J. E. Thornycroft, to the effect that his firm has adopted the War Office system of control as a standard for all their vehicles whether of subsidy model or not.
At a rather later date it may be well worth while to consider whether experience has not demonstrated the possibility of combining with a full subsidy scheme a modified scheme insisting only on vehicles of the right load capacity, and the adoption of all details of the standard control. In this way, if the true subsidy model continues to be somewhat unpopular amongst commercial users, a very fairly adequate reserve will be brought into being without any considerable trouble.
Turning now to the second of the two main points which the War Department have attempted to cover, we find the fulfilment of the scheme beset with much greater difficulties. Every attempt to secure standardisation in the parts of vehicles of different makes must necessarily entail expenditure by the manufacturers, both in getting out new designs and also in arranging for economical workshop processes. Such expenditure is only justified commercially if the sale of the resulting products is sufficient to secure profitable trading. Some allowance, of course, must be made for the added prestige accruing to a firm licensed to build for the War Office, but this is in itself insufficient encouragement. Consequently, every stipulation made with a view to standardisation must be covered by subsidy grants, sufficient to cover both manufacturer and user in respect of any additional cost or disadvantages in operation. The War Department has recognised the impossibility of asking for complete standardisation, and so killing the individuality of different types of vehicle. The tendency of any such process would be to throttle normal competition, and to prevent progress. Consequently, standardisation can only be attempted in certain respects where it appears for one reason or another to be highly desirable. For example, radiators are notably liable to damage, and consequently the connections of the radiator to the machine are standardised to allow of ready replacement of this essential as a whole. The radiators are mounted on trunnions, the bearings of which are in halves, and the positions and dimensions of inlet and outlet connections are definitely fixed. As an additional safeguard, a stout cord in the form of a bar or tube has to be placed across the front of the radiator. The engines are not standardised except in certain details, as, for example, the method of fastening on and driving the magnetos, which are arranged with a view to rapid removal and replacement whole. No high degree of standardisation is possible without incurring great expense and other disadvantages so far as concerns the design of the clutch and the change-speed gear, though the ratios of the latter are determined for reasons which will be explained later.
As regards final drive, some degree of standardisation is possible so far as the axle arms and bushes are concerned. The bearings of the front wheels are standardised so as to make the wheels interchangeable, and the diameters of both the front and rear wheels are fixed. Makers and users are left with a fairly free hand as regards the type of body to be fitted to a subsidy machine, but in general this must be a lorry body with detachable sides and ends at least two feet high, and carrying a frame to take a complete overhead cover. Use is also found for a certain number of box vans.
Many provisions are made in the subsidy scheme with a special view to making the vehicles suitable for working in convoy. In the first place, it is stipulated that all engines shall be fitted with governors which shall automatically control their speed to 1,000 revolutions per minute. This prevents drivers from racing their engines and over-speeding their cars when running light, and also determines a definite top speed, which should be almost exactly equal for all subsidy machines, as it were. Coupled with this, are the provisions as regards change-speed gear. The engine governor having limited the speed of the 3-ton type to 16 miles per hour, and the speed of the 30-cwt. type to 20 miles per hour, the next step is to secure that, when road conditions require the use of lower gears, the whole of the vehicles in the convoy will need to change gear practically at the same point, and when on lower gears will run practically at the same speeds. With this object in view, it is stipulated that the ratio between top and bottom gear shall be about five to one, giving bottom speeds of about three and four miles per hour respectively for the two classes. This provision, taken in conjunction with the stipulated engine dimensions, should secure that every vehicle is capable of tackling a gradient of one in six on normal road surface whether fully loaded or empty. It will be seen that the point kept in view has been the desirability of arranging everything so that drivers of a large number of machines working in convoy—that is to say, running along the same road at short intervals behind one another—shall not have any difficulty in keeping their proper distance, and so in preventing any risk of collisions. For similar reasons the fitting of a ground sprag is made compulsory. The object of the sprag is to prevent a vehicle from running backward if, for example, the driver misses his gear on a steep gradient. The fitting is not necessary on ordinary commercial machines, since the brakes will almost certainly hold the car before it has run more than a few yards, but in the case of one vehicle in a long convoy, those few yards may mean a collision with the following car, and a hopeless muddle causing serious delay. In view of the possibility of some one car failing, every chassis has to be fitted with towing hooks at the ends of the side members of the frame fore and aft, so that each machine can, if required, either be towed or tow another, and any “lame duck” will not obstruct the whole convoy, but can be dragged along to some point where it can be towed out of the way, and the rest can be allowed to proceed.
Other points in the scheme have in view particularly the fact that the machines must be required to operate on very bad and possibly on very hilly roads, and may even be needed to make detours across country when roads are destroyed or entirely blocked. The chief points in this connection are the provision of high ground clearance, which must in no case be less than 12 inches, the stipulation as to size of wheels, which are rather larger than usually found on commercial vehicles, and various stipulations ensuring adequate protection of the mechanism from mud and dust. Generally speaking, these provisions constitute one of the principal difficulties in making the scheme successful, principally for the reason that large wheels imply a rather high loading platform, and this is objected to by many commercial concerns on the ground that it makes loading and unloading more difficult. On the other hand, larger wheels are better for the roads, and consequently it is within the bounds of possibility that trading concerns will presently be compelled by law to put up with their disadvantages. From the point of view of motor users in the Colonies, high ground clearance and large wheels are very valuable and even essential features. Consequently, the subsidy scheme works in well with many Colonial requirements, and manufacturers whose machines are accepted by the War Department probably depend for success of the type to no little extent upon the likelihood of orders from abroad.
“The Autocar” photograph.
SAURER MOTOR FIELD KITCHEN.
In the interests of the proper guarding of the mechanism from mud and dust, the experts of the War Department have considered it necessary to stipulate that all cars must be driven on the live-axle system either through bevel or worm gear. In the first instance, only the former was accepted, but more recently the worm drive, as exemplified by the products of its pioneers, Messrs. Dennis Bros., has met with approval. The point to be noted is that the chain drive—which, in the opinion of many manufacturers and also of many users both at home and abroad is unequalled for heavy work—is definitely debarred. Considerable antagonism to the scheme as a whole was thus created, and one is forced to the conclusion that the reasons for refusing the chain drive were not solely connected with the question of protecting from mud, but were possibly more concerned with the fact that, while a chain drive is probably quite as economical in maintenance as any live-axle drive, it requires rather more frequent adjustments and attention, and possibly small renewals.
In commercial practice, this consideration carries little or no weight, but on active service a breakdown is none the less serious because it is caused merely by a breakage to one link in a chain and not by the entire dislocation of the whole transmission gear. One gathers that, at the present moment, chain-driven machines are in fact being used in the service of the British Army, and in the interests of the success of the scheme in the future, the hope may be expressed that practical experience will show that any fears as to unreliability of this type of transmission from the military standpoint will prove entirely groundless.
When the great war broke out, the position was briefly as follows. The subsidy scheme had not been in force for a sufficient length of time to secure through its means the complete fleet required. The War Department itself owned upwards of one hundred lorries of subsidy type, and a limited number were to be found in civilian service. Among these, the Leyland, which was the first type accepted for subsidy, was probably the most prominent. It has been necessary, therefore, to depend not only on a supply of machines of subsidy type, but in the first instance on the requisitioning of other cars of suitable load capacity, and more lately on the steady purchase of new vehicles of types which, if not according exactly to the subsidy requirement, approximate to it sufficiently to secure reasonable facilities for the easy repair and maintenance of the machines of the transport and supply columns, both of our existing Expeditionary Force, and also of the new armies now in course of formation.