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Overloading: Its Effect on Design.

24th April 1923, Page 1
24th April 1923
Page 1
Page 2
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Page 1, 24th April 1923 — Overloading: Its Effect on Design.
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Which of the following most accurately describes the problem?

LTHOUGH the overloading which is going on at the present moment may be regarded with some misgivings, it will undoubtedly have a beneficial effect on future designs.

Times are hard, and among the small hauliers overloading seems to be More the rule than the exception. Three-tonners are carrying as much as five tons regularly, and, although springs and other parts are suffering, there is not so much trouble as one might expect, when the amount of overload is considered.

One particular model we have in mind was designed about fifteen years ago as a 30-cwt. chassis, and was, at the time, not heavier than other models designed for carrying the same weight. This 30-cwt. chassis was soon found to be able to carry two tons with safety, and from this it crept up to a two and a half-tonner. Then some daring spirits ventured to increase the load up to three tons. Results were so satisfactory that the makers eventually listed the model as a three-tonner, and as this it has given good service all over the world. Under the present conditions prevailing in the haulage business, where so many vehicles have been picked up at a. very low rate after war service, the owners have not shown the same regard for the vehicles as they would have done if the vehicles had been bought new at their original cost. This fact, coupled with the desire to make both ends meet by carrying as much load as possible, has led to what may be regarded as altogether unreasonable overloading.

Although the practice of overloading cannot be too strongly condemned, it is wonderful how some of these vehicles stand up under a load for which they were never intended by their designers. If the manufacturers encourage their designers to keep in close touch with vehicles running under overload they will be able to see exactly what parts are affected by the extra strain and what parta are sianding up well.

Nothing could be more enlightening to a designer than to see his models greatly overloaded, as overloading shows up the weak points, the strengthening of which should improve the breed. The present conditions should enable the five-tonner of the future to be designed so that its weight should not be far above that of the three-tonner of to-day.

It might be asked, "Why should we have to wait for these abnormal conditions for the designers to learn their business? " The answer to this is very simple. The designer cannot afford to take risks ; consequently, he has to allow a certain factor of safety in order to be sure that hie vehicle will not unduly cause trouble by mechanical failures through breakage or wear. The fixing of this factor of safety is an extremely difficult matter, and in many cases it is fixed too high.

The owner of a cheap war-worn vehicle can afford to take risks, that no designer could. Now is the epportunity to keep in close touch with these overloaded 'vehicles and to note carefully what happens. The 'lesson learnt from them should be of the greatest value, and those who do not take advantage of the opportunity will get left behind when new models are being designedin the future.

Alcohol Fuel: Its Far-reaching Possibilities.

THE memory of the public is in some respects curiously short, an although very great interest is always displayed in the question of home-produced fuel, whenever there is a possibility of an increase in the price of petrol taking place, little or nothing is heard of the matter when the

prices of ordinary fuels are stable. . Wherefore, the announcement that home-produced motor fuel with an alcohol base is now commercially available has not been accompanied by any fanfare of acclamation. Nevertheless, the fact is important and may have far-reaching results. We deal with the possibilites at-greater length elsewhere in this issue, and the article is well worth the careful perusal of all interested in economy of running costs and in the question of commercial vehicle develop ment. .

Briefly, Discol fuel at Is. Vd. per gallon isnot meant to be an attractive proposition commercially .when used alone in an engine of the conventional type. Although its cost per gallon is lower than that of petrol, the mileage obtained is appreciably inferior to that of petrol or benzole, and so the running costs of a vehicle would not be reduced. On the other hand, if the best use of the potential energy rontained in petrol is desired, an engine employing a higher compression ratio than is normal is indicated, but on " straight" petrol this high compression would induce very undesirable pinking except when, the unit was operating .under favourable conditions

of load and ap.m. .

Alcohol is a powerful anti-detonant. By using it in conjunction with petrol a compression -ratio that enables a very high mileage per gallon to be obtained is rendered practicable, and over a fair period of use the reduction in fuel costs thus attained would easily overbalance the -cost of the mechanical alterations made necessary by the utilization of alcohol.

• •There is no reason, of course, why manufacturers should not design engines specifically to use alcohol fuel—either pure or in a mixture—and that this will be done before many. months are over we have little doubt. It may not generally be known that one of the largest and best-known fleets of buses operating in this country has been running on a -special fuel for some considerable time with every success, so that 'there is nothing experimental in " non-pinking" fuel that permits of an increase of "miles per gallon.

Should "Spit and Polish" Win the Cup ?

HERE IS an interesting letter in our correspondence columns this week from a driver who feels impelled to criticise the awards of the judges at the recent parade of commercial vehicles held in London under the auspices of the Commercial Motor Users Association. He thinks that too much regard was paid by the judges to mere appearance and he deprecates attaching such importance to mere appearance—which consists of cleanliness, Polish, bright paint, ornamentation, and such like. B4

It must be remembered that the parade of motor vehicles is the modern counterpart of the horse and van and the donkey and cart parades which have been promoted from time immemorial for the sole purpose of encouraging kindness and attention to animals and care of vehicles. They have always been productive of good, the average Britisher loving the sense of competition which such contests provoke. A complicated system of marking would carry a competition of this kind much too far' and it is extremely &Abdul if any system could be devised which weuld be other than arbitrary or which would give a true measufe of value. under every head of marking.

. After all, appearance is a very useful line ofcomparison. It has proved successful in the case of the horse and van and the donkey and cart parades, and we think it works very well in the case of the commercial motelparade. At any rate, it has the merit of simplicity, and does not involve a long-drawn-Out parade or a volume of work in judging, which mug, at some time or other, become burdensome.

Appearance may be employed for the purpose of comparing competing vehicles, but even when this is so it is not valued' so much for itself as for all that is behind it. "Spit and polish" is valued highest in the Navy, because, whilst its outward and visible effects may be obliterated before going into action, it has already helped towards the winning of the action. It is an outward sign of an intense pride in one's job and of deep interest in the medium for carrying on that job. And it has its practical effects. A driver who has pace got his vehicle to look snick and span is encouraged to keep it so—just as a neglected garden discourages the suburban householder, who, however, trieS to keep it in nice order once he has tackled the job and secured a presentable result. Again, clean mechanism is easy to inspect, and the act of cleaning is an incentive to examination and observation of the effects of wear and Lear, whilst, naturally enough, cleanliness tends. to economy in the maintenance of motor mechanism, because the exudation of oil and greas.1, becomes objectionable and measures are sought for its prevention. Our reference to the Navy is rather pertinent to the question, because Naval men are behind ihe fleets of Thomas Wethered and Sons, Ltd., and Shell-Mex, Ltd., and their influence is to be seen not only in the vehicles hut in the garages, the stores, the oil stores, and in. every detail of the running of the fleets. Moreover, one has only to do what we have done—lift the bonnet of one of these Parade winners when one comes across it in the course of its work—to see that the standard of cleanliness can be maintained throughout the year from one parade to the next.

The Danger of Neglecting Steam Wagon Boilers.

MONGST the many thousands of steam wagons in active operation, it is certain that there are many which do not receive that careful attention which is not only desirable, but necessary for efficient and safe service. This applies particularly in the case of those vehicles which have been on. the road for possibly 10 or more years.

We have evidence from no less an authority than Mr. F. J. Bretherton, the well-known steam-vehicle designer, that many wagons are being run with their boilers in a condition which has actually crossed the line of demarcation between safety and danger. During his reply to the discussion, following the reading of his recent_paper before the Institution of Automobile Engineers, he stated that, in some wagons which he had seen brought in for repair, the whole of the boiler stays had fractured, and the shell had actually bulged to the extent of 6 ins. He also mentioned that he could, with one blow, easily have driven the point of a pickaxe through some of the most important plates, so greatly had these been reduced in strength through burning and corrosion. This is a most unsatisfactory state of affairs and is fraught with grave danger, not only to the per eonnel of the wagons, but to the general public. Let it not be thought -for a moment that we, in any way, advocate official interference in steamwagon matters. There is quite sufficient red tape without any more being added to the length. On the other hand, we consider it vital that owners should make certainthat the boilers of their wagons are maintained in good condition and inspected at frequent and regular intervals by men qualified to give an expert opinion as to their safety. Where corrosion has proved to be excessive, exhaustive search should be made into the reasons for this being the case. These may be traced to deleterious matter dissolved in the water, or the lack of that close care and attention which every driver should give to the vehicle under his charge.

It is really remarkable how a device, such as a boiler, can withstand the numerous stresses imposed upon it by the wide range of temperatures to which it is subjected, but we must not expect it to suffer this without its due meed of attention, and it should be the first care of the owner to see that the boiler receives this. Few other parts of a mec.hanical road transport vehicle will respond so readily to fair treatment, and it should be remembered that the boiler is the heart of a steam wagon.

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