Correspondence.
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Exhibition Tours for Motorcars.
The Editor, " THE COMMERCIAL MOTOR."
Sir :—At a time when the proposed van trials, which were postponed last year, are the subject of controversy between the Automobile Club and the Motor Van, Wagon, and Omnibus Users' Association, it may interest you to know that the Beaufort Motor Company long ago gave up depending upon trials for effective exhibition of their commercial motor vehicles. To our mind, trials are of importance merely when they are a means of showing possible customers the behaviour of commercial vehicles under service conditions. The more numerous the numbers of entries in a trial, the more divided the resulting orders are likely to be, and the less the benefit to individual competitors. Following this idea, for some time past we have made a practice of sending out light vans on exhibition tours round the country. The results to us have been so successful that we feel we cannot do better titan to commend it to other firms interested, as we are, in the industrial vehicle trade. • -Yours faithfully,
THE BEAUFORT MOTOR CO., LTD. 14, Baker Street, W., October 1st, 3no6.
British v. Foreign IViotarbisses.
The Editor, "THE COMMERCIAL MOTOR."
Sir -Our attention has been drawn to statements published in the Press to the effect that orders for motor omnibuses for London, to the value of .;300,000, have been placed with foreign firms by some of the motor omnibus companies of London. Being the leading firm manufacturing and supplying British-made omnibuses, and being of the opinion that this statement is open to question, we consider it likely to mislead the public, and prove prejudicial to the interests of British trade, and the British motor industry in particular. It is represented that the Secretary of the Vanguard Company has stated that the French and German manufacturers were ten years ahead of the British in the motor business, a statementwhich we must forcibly repudiate, so far as commercial vehicles are concerned, and, as evidence of this fact, we may mention that there are upwards of 200 of these omnibuses in daily use in London supplied by our firm, which are entirely of British manufacture. The Vanguard Company are only one of many concerns running motor omnibuses, and we would point out that the Road Car Company have now nearly as many machines as the Vanguards, or soon will have. Also, the results of the working of the Road Car Company's vehicles have proved that they are snore reliable than that of any other type. All these machines are manufactured by our firm, together with the greater portion of the cars run by the London General Omnibus Company, the Great Eastern London Omnibus Company, and other large firms.
These British machines have proved their superiority over any other type of omnibus in London, especially with regard to the minimum of annoyance caused to the public due to absence of smoke emission. Likewise, the silent running and reliability are featuresof importance; moreover, the accomplishment of an average of n5 per cent. to 99 -per cent. of total cars kept on the road during the last 6 months, for a distance exceeding 500,000 miles, which has been effected by the Road Car Company, is a performance which speaks for itself. In the face of this information, we consider the published statements most misleading, as, although the motorbus was of German inception, now that developments _have transpired and improvements been effected on the original models, the motorbus of to-day is of English development. By the end of the present year, on British cars Of the Straker-Squire model will be in daily use in London, and, during the coming year, we alone will produce 1,000 cars, whilst other British manufacturers arc adding their proportions to the above, so that it is not likely that the leading English manufacturing firms will be ousted in the matter of this special business, especially taking into consideration that, by absolute proof, it is ascertained that English cars are giving better results in London, or, at any rate, results which have not yet been achieved by firms employing foreign cars.
As these statements in the general Press are prone to create prejudice to British trade, we trust that you will give publicity to this communication.—Yours faithfully, For SIDNEY STRAKER AND SQUIRE, LTD.
Nelson Square, S.E. L. R. L. SQUIRE., Director.
The Important Question of Tires.
The Editor, "THE COMMERCIAL MOTOR."
Sir :—Referring to the interesting article by Mr. Georges de l'relle de la Nieppe, in your issue of 27th ultimo, headed " The linportant Question of Tires," will you allow me to make the following remarks, which I will confine to the construction of the front wheels only?
The object of an elastic tire, be it pneumatic or solid rubber, or other medium, is to absorb vibration due to an unequal road surface, and, to -obtain this, it is necessary with a solid tire that the pressure per square inch on the rubber should not be more than a certain amount, otherwise the elasticity will disappear and rapid disintegration, or deterioration, of the rubber will result from the over-straining of the molecules of the rubber ; in a pneumatic tire it is necessary to have a sufficient area, otherwise the pressure becomes too great for the material in the tire to stand the strains. In attempting to obtain a large enough area of rubber in contact with the road surface, and to keep the pressure per square inch low enough to give the desired flexibility and life to the tire, difficulties are at once encountered, CRC of which is that, as the tread is increased, the steering is very much stiffer, as pointed out by Mr. Georges de Prelle de in Nieppe, thereby making driving extremely difficult, wearing out the steering mechanism, and, thirdly, leading to rapid depreciation of the tires, due to the grinding effect on the portion of the. tire in contact with the ground when the steering wheel is turned (such as is often the case when a motorbus is starting from the kerb, when the driver will slew his front wheels round in starting away from same), and also when going round corners, owing to the fact that the outer portion of the tire travelling over a bigger distance of ground_ than the inside portion of the tire necessarily leads to a straining and grinding of the material as the wheel is travelling. Now, in my opinion, the solution of these difficulties is contained in constructing the front wheels so that two or more tires on the smite wheel are capable of having a differential motion between each other according to the conditions under which they find themselves. Take an instance where three tires are mounted on their own iron rims, so connected to the wheel surface, or wheel hub, as to be capable of independent motion circumferentially round the axis; it will be seen that in going round a corner the three tires will all be going at different rates, thus preventing the grinding action on the ground; they will also be going at different speeds when the steering handle is suddenly turned, supposing the bus to be stationary, as in the instance referred to above, thus getting over steering difficulties, and The grinding action on the tires. I may say that 1 have provisionally patented this principle, which I think will directly overcome the difficulties referred to by Mr. de PreIle. Regarding his remarks on the question of skidding, 1 should be obliged if Mr. de PreIle will communicate with The writer on this subject. Mr. de Prelle ends his interesting article by the question—Does the differential gear increase the skidding effect? I think the answer to this is certainly in the affirmative, under certain conditions, such as, for instance, the front wheels being on a very slippery surface, and one back wheel meeting a serious obstruction on the road : there will be, under these conditions, a greatly increased -driving force on the hind wheel which does not meet the obstruction, more particularly if this wheel is on a dry portion of the road on which it can get a good grip on the surface, and the result will be that this latter driving wheel will tend to go at that instant, under these conditions, at twice the speed of the one which has met the obstruction. Considering the impeded wheel to have been suddenly slopped by the obstruction, then the point of contact of the wheel which met the obstruction will form a centre round which the other driving wheel will tend to slew the whole vehicle, and, if the front wheels have, as stated, little resistance to transverse skidding, the result will be a pure spin round. I have often conceived this set of conditions in my mind, and should much like to hear the views of others interested in this question.—1 am, yours faithfully,
CHAS. WM. FULTON. Paisley, N.B.
September 28th, 1906.
Oscillating Front Axles.
The Editor, " THE COMMERCIAL MOTOR."
Sir :-1 am sorry Mr. Guthrie should think that 1 have treated him with discourtesy, as nothing was farther from my intention.
, In regard to that part of his letter in which he accuses me of making a statement which I know to be incorrect, 1 would ask him to compare the front wheels, axles, and springs of the Foden wagon (with oscillating axle) with, say, the Gorton lorry (with fixed axle), a comparison which, I think, he will admit proves my contention to be correct.— Yours faithfully, HENRY A. NEAT-. " Somerville,-" Richmond, Surrey, Sept. 29th, 1906.
The Editor," THE COMMERCIAL MOTOR."
Sir :—Referring to the recent correspondence which has appeared in your columns on the subject of oscillating axles, and having had a large experience in the construction of commercial vehicles, we fully appreciate the remarks made by your various correspondents. There is no doubt, in our opinion, that a vehicle, fitted with the ordinary type of oscillating axle, runs with considerably less vibration than one with a fixed or rigid axle. One serious objection to the ordinary rocking axle is that the front wheels constantly run out of track with the rear wheels and at the same time necessarily leave their upright position and run upon one edge of the tire, and, as the width of the tires is usually from 5 to -6 inches, this must certainly help to loosen them and otherwise damage the wheels, by reason of the cross strains set -up. In running over an obstacle with one wheel only the greater part of the weight of the front of the vehicle is thrown upon the opposite wheel, which is out of its upright position and least able to receive the extra weight, as is clearly demonstrated in the diagrams published in your issues of September 13th and 20th. It is, therefore, essential that the wheels should be kept, as far as possible, in their N'ITtirld position. This can only be done by using an th_eillating
axle having parallel Motion as shown 'n the accompanying rough diagram. From this will be seen the advantage that this type of axle has over the ordinaryrocking type, especially upon rough roads. The fact that a large number of steam wagon builders have adopted the rocking axle is certainly evidence that there must be an advantage in mimimising the road vibration and reducing repair bills. We have found, by the practical experiences of several years, that the advantages of using the oscillating axle with parallel motion upon 5-ton steam lorries are such that we have designed and are adopting a similar axle for our petroldriven commercial vehicles and omnibuses, as well as for touring cars.
It may la: argued that, in using a rocking axle on front wheels, it is more difficult to steer, owing to the front wheels getting out of track with the driving wheels, but this objection is entirely overcome by the use of the oscillating axle with the parallel motion. Moreover, ihe strain upon the rubber tires and road wheels of a vehicle fitted with an axle of this description is not so great as on one fitted with a rigid axle.—Yours faithfully, THE HERCULES MOTOR WAGON AND ENGINEERING COMP:1NY. Leverishuline, Manchester, September 28th, 1906.
The Dearth of Motorbus Drivers.
The Editor, "THE COMMERCIAL MOTOR."
Sir :—I was much interested in your article on the "'Dearth of Motorbus Drivers," and can fully endorse your remarks. T venture to say that, if some better system of teaching drivers were employed, the dearth, if there be one, would soon become a thing of the past. Let me quote my own experience. I have driven small cars, electric tramcars, and electric trains (1 should be a driver on a London tube now, but that the underground work affects my health), and, heing out of employment, I thought I had sufficient " mechanical aptitude " and road experience to become a motorbus driver. I applied to the leading companies, and was told there were no vacancies; but at last was taken on by a certain firm and told to come up and practise. There were several other learners there, and, during my month's " tuition," we went out four times; then went up to Scotland Yard and—failed ! I ventured to complain of the lack of practice, and in reply was told by the manager, in terms more forcible than polite, to clear out, which I did. I am still out of employment.
If this is the way the companies treat the men, I see no cause for wondering why motorbus drivers are scarce; but 1 should, also, like to know why the companies say there are no vacancies?—Yours faithfully, "DISH EARTEN ED."
London, September 3oth, 1906.