AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

A Curious Specification.

6th May 1909, Page 4
6th May 1909
Page 4
Page 4, 6th May 1909 — A Curious Specification.
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

By Henry Sturmey.

The Guardians of the Poor of the West Ham Union are in the market, for a motor ambulance: they have issued a tender form, with specification of the vehicle required. This is a study and makes one wonder who the genius is upon whom the Guardians of the West Ham Union rely for their motor information. My draughtsman, when 1 showed the specification to him, asked if it was the gardener !

In the first place, the specification is issued as the requirements of the Guardians for which motor manufacturers can quote, but motorcars are not manufactured in single units, or cut out of a chunk of wood, and it is wholly impracticable to specify exact details in mechanical parts, as is done here, unless, of course, it is the intention of the Guardians, regardless of the offers made by other makers, to place the order with one particular firm whose car is known to correspond to the details specified. It serves no useful purpose to specify details which are equally well done in ways other than that specified; it only ties the hands of the manufacturer, and prevents good firms tendering, owing to the large amount of alteration from their standard which is necessary to comply with the specified requirements.

For West Ham, the ignition and hand accelerator are to be placed " under steering wheel on column." Now, this is a system which is, almost universally, throughout the trade, done the other way ; the ignition and throttle levers are placed above, instead of under, the steering wheel. General practice has accepted this as the best, and, for the purpose for which the vehicle is required, it can surely make no difference to the Guardians which way this detail is carried out.

Next, we come to the engine, which is specified as a " Dennis, or other approved engine." Now, to start with, as Messrs. Dennis are not manufacturers of motors for the trade, why is their engine specified? It is true another " approved " engine may be quoted for, but why even mention this? If the engine is not approved, of course, the tender would not be accepted.

In regard to the clutch, seeing that there are several systems which are equally approved by experienced motorists and engineers, it seems hardly a desirable thing to specify the exact details of one kind only : it ties the hands of manufacturers too much, if one be, let us say, fitting a Hele-Shaw type of clutch—which, for motorambulance work, would appear to be even better adapted than the coned clutch specified—one would not alter one's clutch mechanism to secure the order.

Gear requirements, coupled with the engine and load requirements, are almost humorous. It is specified, in the first place, that there shall be a bronze gearcase, which very few firms fit, and, secondly, four speeds with a direct third and an indirect fourth, whilst the speeds respectively are to be 3, 7-1, 14, and 16 miles per hour " with the engine at normal speed." As, however, it is also specified that the engine must be " so arranged "--I suppose governed-" that it cannot exceed a speed on the top gear of 16m.p.h.," it is plain that the engine must be governed at its normal revolutions. When this requirement is considered, in view of the fact that a four-cylinder "41in." engine is required, and that the vehicle is a motor ambulance "to seat eight passengers or two stretchers," the absurdity of the requirement will be still more apparent. Eight passengers will weigh, approximately, 12cwt., and the alternative of two stretchers with occupants and staff will weigh less. The body may 'be described as that of a light omnibus, such as would be built on a chassis constructed to carry 15cwt. maximum net load. Now, in the first place, why a 41in. engine—which may be made to give anything up to close on 50h.p..—passes the under-standing, seeing the small load with which the engine will have to deal, and the low speed at which the vehicle is required to run. Au engine of half the R.A.C. rating would effectually deal with such a load at such a speed, and, moreover, with a 16-mile gear, would surmount, with a frill load, gradients of, approximately, 1 in 12, or better, without any change of gear at all, whilst, with an engine such as that required in the specification, probably 1 in 8, or even 1 in 6, would not pull down its speed materially. Why, then, the demand for four speeds, and why the indirect fourth ? This is the most astonishing requirement of all. The third direct speed is but 14m.p.h.: why the complication of an indirect fourth to get an additional two miles per hour out of a car with such an engine as that specified? As a matter of fact, with an engine of the power specified, neither two nor three speeds are necessary, as its flexibility would enable it to work through the entire range of speeds required, and to take its load anywhere within reason, and this, too, without any indirectness of gears, and, of course, by throttle and ignition working only, and without any gear changing at all, so that it would not entail the jar of changing gears. If a car be supplied to the specification, however, I think it may be taken as pretty certain that neither the second nor fourth speeds will ever be used, or, if the second be used, the first will not be, so that this complication is badly superfluous. If it be insisted upon, then, surely, its combination with so large an engine and so low a gear is an anachronism.

Coming to the back axle, we find that the " Dennis patent worm drive, or other approved axle " is specified, and the same remarks apply as those printed above in relation to the engine. A parallel-pinion differential is mentioned, and here is another non-essential detail in which the specification differs from that of the great majority of cars, and in a particular, too, which will keep firms from tendering, as a change of system here would necessitate a new design of axle. The exact dimensions of the axle sleeves are specified, which also seems superfluous, unless mentioned as a minimum, and the same remark applies to the requirement that the arms on which the wheels run are to be 1.1in. in diameter. If the tendering manufacturer differs 1-16th of an inch from this particular, will it jeopardise his chance of acceptance, and, if not, why specify the exact figures, unless, as I have stated above, as a minimum?

The frame is to be of channel steel, not pressed steel, though quite probably pressed steel is meant, 4in. by 2in. by 2in. by—please note this—fin. Here, we have a frame heavy enough to carry 3-ton loads, and no manufacturer building a car of the type required would think of putting in so great a thickness.

Another point which invites comment is the petrol tank, which is to he placed under the driver's seat, to carry 20 gallons, and to have " gravity feed aided by pressure." With a tank placed in this position and the whole system constructed for gravity feed, there is surely no need to have pressure as well, and why the requirement of 20 gallons capacity? This ambulance, it must be remembered, is a parochial one. It is scarcely likely that the Guardians of the Poor of West Ham Union will be travelling all over the country to collect patients for their hospital. Even a 41in. engine, doing light work such as this, should not consume more than one gallon per 15 miles, and why the Guardians want a petrol capacity for 300, miles, when probably the vehicle would never be required to run more than 30 miles at one journey, strikes roe as being at least peculiar and inconsistent with the reasonable requirements of the case.

Lastly, why is it necessary to specify that the fan shall he driven by a flat belt, when a round leather one, or a spring-wire one, would not impair the efficiency of the vehicle, should either happen to form a part of any firm's standard equipment?

Tags

Organisations: West Ham Union
People: Henry Sturmey

comments powered by Disqus