PNEUMATICS FOR THE ARMY.
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"The Inspector" Wants to Know What Specific Advantage the W.O. Anticipates from Pneumatics in War Service.
• T FIRST, I was rather inclined to think, from War Department had dropped a veritable bombshell amongst the ranks of commercial vehicle builders when they issued their new so-called specification for the W.D. standard maehine. I expected to find something very drastic and sensational ; to find that the authorities had decided on something as their standard for Royal Army Service Corps transPort units that would have indicated developments on very unconventional lines, developments that might have been indicated as desirable when the thousand and one records of mechanical transport performances during the war had been examined and collated.
But the specification, as such, when properly digested, really, after all, only consists of a very mild set of recommendations with any amount of loopholes. It departs very little from what is good sound commercial practice. As a matter of fact, there is remarkably little definite stipulation as to design, and the very fact that several organs of the Press have taken this as a basis on which to offer to their readers suggested designs indicates the very broad nature of this official set of stipulations. There are not a few machines already in existence that, with but little alteration, would probably with sufficient closeness approximate to the War Department's new requirements as set out in this document.
If there is anything sensational in this matter, it is the fact that the authorities have apparently become convinced that the future transport unit is to be one of comparatively lightweight capacity, and, moreover, that it is to be shod with pneumatic tyres. The latter part of this decision is, in a way, sensational, and it must be presumed that this concluiion was arrived at as a result of consideration, not only of the vehicles, but of the tracks on which they ran. It was found during the war time that the cost of maintaining sufficiently good highways was enormous, and that it immobilized vast numbers of men who had to be fed, protected and transported. The writer can only assume that the decision to use pneumatics and on lighter units is one arrived at with a View to reducing the cost of maintaining the roads on which they should run. But surely in war time army transport had only a relatively small share in ruining the roads, artillery and aircraft certainly did their share, and the transport of vastly heavier units of armament than those represented by W.D. standard lorries must have accounted for a large proportion of the cost and trouble of maintaining highways.
What other reason is there for the adoption of pneumatic tyres on an Army machine? There is certainly the great risk of a vehicle being a " casualty" due to puncture, either on account of bad roads, or on account of artillery or machine-gun fire—that a casualty in a convoy is a very serious affair. The pneumatic is, of course, lighter on road surfaces and it enables higher speeds lobe maintained with less damage to the chassis, but higher speeds are not required nor can they be used in war time. Frankly, I should be very interested indeed to learn what are
the advantages that are expected to accrue for military purposes from the standardized fitting and use of pneumatic tyres.
At first, one is inclined to accept this part of the specification as being_ in line with modern developments. The use of lighter units, and the mounting of them on pneumatics, is in accordance with the considerable development in this direction that is_noticeable, for instance, in connection with char-h-bancs traffic, buf there has not been any correspondingly startling progress so far as general road haulage is concerned. Here and there developments are taking place in the use of pneumatics, but they are insignificant, considering the time that has been spent in tyre propaganda work.
There is still, whatever may be said to the contrary, a very large demand for the four-ton unit in civilian work. At any rate it may be reasonably assum6d that if the four-tonner were not so much in evidence on account of the aftermath-of-war employment of sitch models, we should probably revert, in a very large measure, to the popularity of the three-tonner, which was the outstanding feature of the commercial vehicle programme prior to 1914.
It will be recalled that the three-tonn-er was then the popular machine. The W.D. four tonner was really a three-tonner, so far as the army authorities were concerned, with a three-ton net load ; the balance was a margin for strength and for the carrying of excess loads, equipment and so on. Of course, one recalls quite well that in war time a large number of the four-tonner units were employed for carrying loads much below their specific capacity. On the other hand, there are on record many occasions when the .capacity of the four-tonner to carry five or more tons in emergency was invaluable and saved many a ghastly situation and a great deal of very valuable property.
The 30-cwt. machine will be faster, it certainly will be vulnerable on bad road surfaces, although it will not contribute so much to the disintegration of such surfaces ; it will mean the employment of a much larger number of units to transport emergency loads.
Of the other stipulations in this so-called specification there is very little to write. Few manufacturers will have difficulty in complying with the very wide recommendations that are.made. The 100snam. engine is a suitable size for a slow-running unit. Such things as towing hooks, drawbars, frame bracing and so on are merely ordinary requirements and need not cause a tremor to the most harassed of designers.
It may be of some interest to inquire whether the authorities have the idea of developing trailers to any considerable extent. They stipulate that the new machines should be capable of hauling them, but there, again, this rather sensational adoption of the pneumatic tyre is likely to cause some query as to its suitability when hauling trailer loads over bad surfaces.