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Opinions from Others.

12th January 1911
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Page 15, 12th January 1911 — Opinions from Others.
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Which of the following most accurately describes the problem?

The Steering Gear of Motorbuses.

The Editor, THE COMMERCIAL MOTOR.

[1,287J Sir,---It will be remembered that the valise of the fatal accident in Regent Street to one of the London General Omnibus Co.'s vehicles, as revealed by the coroner's inquest, was that " one of the front wheels of the omnibus came into (xdlisien with a motorcar, with the result that the steering wheel was knocked out of the driver's hand, he thereby losing control."

Consequent upoa this finding, and without studying the question, a gentleman, well known in motor-racing circles, has written a letter to certain daily papers pointing out what. he considers to be defects in the design of the steering gear of London motor omnibuses. This letter has not only caused other persons to write on the SR1210 subject, but suggestions have been made that the police authorities should frame regulations making it compulsory for the omnibus companies to adopt this gentlemairs views. I should, on this account, like to point out that, not only would the adoption of the racing-car type of steering gear, which it is suggested should be adopted in motor omnibuses, put the operating companies to very-considerable expense, but that the fitting of such gear would, instead of preventing accidents of this character, render them far more likely to take place. The desideratum in the design of a steering gear is that the driver shall be able, in the time available, to exert the maximum required power in deflecting the front wheels of the vehicle. It will, therefore, be obvious that, the higher the speed at which the vehicle is travelling, the shorter will be the time available to alter its course ; so that it has been found necessary to fit high-speed cars with a considerably-higher gear ratio between the steering wheel and the front road wheels, than that which is necessary on motorbuses' whose speed is comparatively low. In order somewhat to compensate for this high gear ratio, larger steering wheels have been fitted.

Excessive rake on the steering columns of high-speed cars has also Leen introduced, in order to permit the use of a low driving seat, and so to reduce the gross wind resistance of the vehicle. This excessive rake has also enabled the driver to handle a wheel of larger diameter more comfortably than he could if the column were approximately vertical.

Now in designing a steering gear that shall be most suitable for a motor omnibus, a steering wheel is selected of slid' a diameter that it can he most-easily handled by the driver, and this has been found to be one of about 16 in., or a distance which corresponds with the width between the driver's arms when they are extended straight from his body. The steering column is then positioned at an approximately-vertical angle, and this permits the driver to exert the maximum amount of power: in this position he, is able to obtain a direct pull on the rim of the wheel with one hand and a direct thrust with the other. As the wind resistance due to the arker's body on vehicles of this type has no influence on the power required to propel the machine, the driver's seat is made of a similar height to an ordinary chair, for years of experience have proved this to be the most romfortable to work in for long periods at a stretch.

Since an omnibus is always driven at a comparativelyslow speed, the driver has a considerable period of time in which to alter the course of the vehicle so that a lower gear ratio may be fitted between the steering wheel and the front wheels of the vehicle. With a given diameter of steering wheel, he has a considerably-greater eontrol of the front wheels than he would have if the raring-car type of gear had been adopted. Should advocates of the excessively-inclined steering column wish to ascertain which position of the column gives the driver the greatest control over the wheel, I would suggest that a rough model be constructed as per the following sketch, and that a test should be made with two drivers of equal strength, when it will he found that the driver with the vertical column will be able to turn tile wheel in the hands of the other man.

When a driver is facing a steering wheel, he is able to exert only a small amount of turning power, and this is clearly demonstrated to anyone who may watch a sailor's steering of a ship with a hand-power wheel; so long as the vessel requires little helm, he will stand in front of the wheel so that he can turn it readily in either direction, but, so soon as he wishes to put the helm hard over, he will move round in order to face the rim of the wheel and pull the spokes down from the top so as to get a direct pull upon them. The driver with the vertical column will be able to turn the steering wheel—other things being equalmuch more easily than will he with the raked column, because the former can exert a pull with his arms and his chest muscles, while the other man has to depend on the strength of his wrists almost entirely.—Yours faithfully,

E. GODFREY BREWER, M.T.Mech.E.

The Circus Tricks of Taxi-drivers.

The Editor, THE COMMERCIAL Mime.

[1,288] Sir,—During the recent greasy weather, I have been led to wonder how many hundreds of pairs of taxicab front wheels are daily stressed to their utmost extent by unthinking drivers, who seek to do smart things in the matter of steering on slippery surfaces, and, in so doing, attempt to drive at full speed on full lock. The licensing authorities at Scotland Yard rightly insist, in order to minimize traffic hindrances, that taxicabs shall be enabled to turn completely in the width of a 25 ft. roadway in the Metropolis. With convenient wheelbase, therefore, it is necessary for constructors to provide a very-large angle of lock, in order that the cabs may be swung round in the prescribed distance, and it is this large angle of lock of which the drivers take unfair and thoughtless advantage, to the detriment of the tires, of the steering connections and of the wheels themselves. How few of these men, when they perforce have to execute some short-radius turn in the stress of traffic, realize that if they withdrew the clutch they would do but-little damage or run but-little risk ? The majority of such men, however, pulls round corners and makes complete turns at full lock with the engine driven hard. It is unlikely that, with a big lock provided, drivers will be taught readily to use less than the full lock. In most circumstances, its use conveys the impression to the ignorant onlooker that the driver is a miracle of circus tricks, and in this the onlooker is not far wrong, but the damage and risk of such behaviour, to which I have already referred, is not apparent to the uninformed and non-technical onlooker, or even, very often, to the driver. It is quite easy to pick out the mechanically-minded driver from the crowd of men who know almost nothing, and who realize nothing more than that the cab is a machine which it is possible to force to an amazingly-high limit. The sooner owners can persuade unthinking drivers that a crablike motion along a greasy road is neither picturesque nor safe, the sooner they will save large sums in the matter of wear and tear of tires, wheels, stub-axles, etc. I think you might very usefully draw attention to this evil.—Yours faithfully,

P. C. MEERS.

Heavy Motorcar Axle-weights.

The Editor, THE COMMERCIAL MOTOR.

[1,289] Sir,—I have read with interest the letter appearing in your issue. of 29th December, and signed by " An Owner near Bolton." In this letter, it is stated that " Under the Heavy Motor Car Order, a total moving weight of 20 tons is permitted for two vehicles, etc." 1. should be extremely obliged to an " Owner," or to you, Sir, if I might be given the authority for this weight of '20 tons, as, in registering a steam tractor and trailer, 1 noticed the following clause in the regulations which appeared on the registration form:— " The sum of the registered axle-weights of all the axles of a Heavy Motor Car (that is, including a trailer) shall not exceed, when laden, twelve tons."

This has always been my interpretation of the Act.— Yours faithfully, REGISTRATION.

nik correspondent sure of the words in parentheses? They should not be on the form, and are not in accordance with the law, as 12 tons is the maximum gross weight for the heavy motorcar only. The trailer and its load may weigh another eight tons ton two axles).—F.n.] The Editor, THE COMMERCIAL MOTOR.

[1,200f Sir,—In your issue of the 29th ult., there appears a letter [No. 1,282], signed by " An Owner near Bolton," in which letter he refers to the net and gross weights permissible with motor wagons. Both myself and many of my friends who are seriously interested in motetwagons, steam tractors and all other vehicles under the Heavy Motor Car Act, have always read the Act of Parliament relating thereto to imply that when a gross load of 12 tons is attained, whether on a wagon only, or a wagon and trailer, or a steam tractor and trailer, not a pound more can be added to that. gross load without making the thing illegal. " An Owner," in his letter, is very much afraid that the attention of local authorities will he called to the overloading of motor wagons. If this gentleman can haul 12 tons net, or 20 tons gross, over roads in this country, with one person in charge, and on driving wheels some 4 ft. in diameter, and at speeds of five miles per hour, and not pay a single penny for licence, I think he will have no cause to grumble if the road authorities and ratepayers take exception. I am assuming that 1 have read the Act correctly-, and that " Owner " is wrong. If Jam wrong 1 apologize to " Owner."—Yours faithfully, PUZZLED. L" Owner" it not wrong—ED.]

The Editor, THE COMMERCIAL MOTOR.

[1,291] Sir,—A far-more-serious point, in connection with heavy-motorcar axle-weights, arises from the ignorance of certain licensing authorities. Readers of your paper will be aware that the regulations prescribe that there is to be painted on the off side of every heavy motorcar a statement of the weight of the vehicle unladen, and of the registered front axle-weight and the registered hack axle-weight, and, in the regulations, it is explained exactly what is meant by registered axle-weight, viz., the maximum weight up to which it is legal to load the axle in question, taking into consideration the nature and width of the tires, and the general construction of the vehicle. It is further provided, that the registering authorities, if they are not satisfied with the owner's statement of the axle-weights which he wishes to he registered. can have the vehicle weighed, in order to ascertain for themselves what ore the axle-weights to be entered in the register, and to he painted on the vehicle.

This has been interpreted, by certain wrongly-advised authorities, to mean that they are to weigh the vehicle first of all to ascertain the unladen weight without stores, water, fuel, accumulators, and so forth, and next that they are to weigh each axle with fuel, etc., aboard, but with the vehicle unladen. These councils then insist that the axle-weights thus ascertained shall be inserted in the register as the registered axle-weights. In reality, they are axle-weights in working order, but unladen, and, therefore, immediately any cargo is put on the vehicle, or even

when the driver takes his seat, the registered axle-weights are exceeded. 1 do not know to' what extent this practice is prevalent, but it certainly is the practice of the County Borough of Brighton, and of the County Council of West Sussex, of which facts you, Sir, may be unaware.

As an example I may state the ease of the fire-engine recently purchased by the Corporation of Worthing. This motor firs-engine is fitted with rubber tires, and it would be legal to load it up to such axle-weights that the sum of the two axle-weights shall not exceed 12 tons, and that no axle shell have a greater weight than eight tons; but, if it were loaded to. this extent, the legal speed would only be eight miles per hour, and, as it is desired to run it at 12 miles per hour, it is necessary that the axleweights should not exceed six tons. The Town Clerk of Worthing would, therefore, have been justified in insisting that the back axle-weights should have been registered as 5 tons 19 cwt. 3 qrs., and any weight not exceeding the same amount for the front axle. But the county authorities would not accept such weight, and insisted on weighing the axles of the motor fire-engine separately, with, of course, -the fire-fighting equipment on board, but no men, and they ascertained that the axle-weights in this condition were 13 cwt. 3 qrs. ort the front axle, and 3 tons 7 cwt. 3 qrs. on the back axle. What is the result:" As soon as the firemen have taken their places, these axleweights are exceeded, and it is technically illegal to work the vehicle. Fortunately, no prosecutions have taken place along the south coast for exceeding the registered axle-weight, but it is a fact that every motor vehicle registered in Brighton or West Sussex exceeds the registered axle-weights whenever it carries a load. If, therefore, such a vehicle were to go with a load to one of the places where the police are so sharp on weighing the axles, prosecution would inevitably follow.

It should, surely, be the duty of the Commercial Motor Users Association to ascertain from the various licensing authorities as to which of them places this misinterpretation on the provisions of the Act, and to endeavour to get them to realize what hardships might result, and to register the proper axle-weights instead of these erroneous axle-weights which they have improperly entered in the register—Yours faithfully, SAD BUT AMUSED.

rit is incredible that any authority should he advised as is above related: the courses indicated do noi cemply with the Order of the Local Government Board, whose attention we shall draw to these anomalies. —Iorj Epicyclic Gears for Ambulances.

The Editor, The COMMERCIAL MOTOR.

[1,292] Sir,—It has often struck us, that the grinding jar and noise frequently made when changing gear must be exceedingly distressing to patients; who are seriously ill when travelling in motor ambulances, and that some such system of frictional engagement like that employed on the Lotis cars should prove especially suitable for ambulance work. It is, therefore, gratifying to us, as makers of the Lotis vehicles, recently to have received several orders for vehicles of this type, and to have two under construction, at the present time, for the Smetbwick and Stoke-on-Trent Guardians respectively. These vehicles are built with four-cylinder engines, having magneto ignition and automatic pump lubrication. The Lotis " foolproof " frictional-engagement gear is employed, and a further assistance to quietness and smoothness in running is provided by the employment of worm drive, whilst. comfort in travel is secured by the use of 36 in. wheels, large pneumatic tires and long many-leafed springs. The bodies of both ambulances, which are being built by Hewer's of Coventry, are of the bus type, and the vehicle for the Smethwick people is being fitted with three interchangeable bodies, two of which are for the conveyance of soiled linen—one of these, being for the conveyance of affected linen, is lined with enamel plates.

This new development of the Lotis vehicles should, we think. appeal to your readers.— Yours faithfully,

Coventry. STCRME1,MOTORS, LTD.


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