Correspondence.
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To Motor Lorry Owners and Drivers.
The Editor, "THE COMMERCIAL MOTOR."
Sir :—The " Straight Talk by a Driver," in your issue this week, is to be commended. There are, undoubtedly, many " owners " such as he writes of, and these are worthy of the same condemnation which was extended to the class of " drivers " whose motto is not " give and take," but almost wholly " take."
No reasonable " owner " will expect his man's mind to be eternally centred on " coal, coke, and oil "; nor will he expect bin, to be out with his lorry until 8 or 9 o'clock every night; but, let " a driver " become " an owner," employ a driver, and, after paying him reasonable wages, find in him one of the class which cannot too strongly be condemned, and it is safe to say his views on " drivers " would be considerably altered. "A Driver " is probably of the type of man contemplated in the French proverb A prurient man is like a pin ; his head prevents him from going too far." Contrast him with the type attacked and —" 'nuff said."—Yours truly, " OWNER. " Manchester.
The Adjustment of Brake Bands and Clutches for Epicyclic Gears.
The Editor, " THE COMMERCIAL MOTOR."
Sir :—In your last issue, dealing with the question of epicyclic gear, you spoke of the need for adjustment of the controlling brakes and clutches, and, although we do not think you meant it so, from the way in which it reads it might be implied that constant and very frequent adjustment here is necessary. Will you permit us to say, therefore, that, so far at any rate as our patent " Lolls " control gear is concerned, this is not the case. Whilst we provide adjustment for all three of the control pedals, this adjustment is rarely needed, as may be gathered when we say that our demonstration van, which has been doing very strenuous work over 6,000 miles of travel, has, up to the present, only required a single adjustment of each of the three lever connections.
The toggle adjustment which locks the clutch in gear for the top speed is the only one where any accuracy of adjustment is required ; but this adjustment is easily made. So far as low speed and reverse is concerned, it is only necessary to make adjustment when the pedal lever gels down to the foot-board in front. There is a very large amount of working margin allowable before this point is reached, and, then, any tendency to slip the gear control is met by a little harder shove on the pedal. We mention this, as your readers might conclude that constant fiddling with these parts is necessary, which, as we have above shown, is not the case.—Yours faithfully,
Coventry. STURMET MOTORS, LTD. Road Wheel Construction.
The Editor, "THE COMMERCIAL. MOTOR."
Sir :—Through some oversight, in the first portion of my article. I seem to have written that in the spokes of the Stagg and Robson wheel "there is no tang." This of course is not so; the spoke end is carried in a shoe, as I wrote, but the tang projects through the shoe and enters the felloe in the usual manner. I trust you will find room for this correction.—Yours faithfully,
REGLD. G. L. MARKAAm, Consulting Motor Engineer.
143, Strand, W.C.
The Editor, " THE COMMERCJAL MOTOR."
Sir :—We were much interested_ in the very able article on road wheels by Mr. R. G. L. Markham in the last two issues of your paper, but should like to enter into a discussion on a few of the points raised.
We quite agree that the vast majority of commercial vehicle makers devote too little attention to the subject of wheels, and are only too willing to wash their hands of all responsibility for failure of their vehicles through wheel and tire troubles. One of the very few subjects dealt with exhaustively by the judges, in their report or the recent commercial vehicle trials, was this question of wheels, and they remark on the defects of both the all-steel and all-wood types.
Mr. Markham, referring to the composite wheel (i.e., steel with inserted wood blocks), is doubtful if the wood is capable of withstanding the hammering action of a rough road. This depends largely on the design, whether the wood is well supported by the wheel casting and is not weakened by an excessive number of drilled holes. In our "Herculean" wheel, the wood is supported in a channel cast on the wheels, the flanges of which reach well up the sides of the felloes, in such a way that, even if the wood blocks were to crack, no collapse of the wheel could take place, the only holes drilled through these fences are those which clear the tire rivets or studs. The reason why all-steel wheels are giving way to composite wheels, in cases where steel tires are employed, is due, as stated, to the excessive vibration set up when travelling on hard or sett roads : this causes trouble through cracked spokes in the wheels, stretched tires, and of course considerable damage to the vehicle itself. The composite wheel deadens this excessive hammering, and the wood felloes expand as the tires stretch, so that the tires have been found to require repressing only once in 12 months' service on a 5-ton steam wagon.
We do not agree that the weight of cast steel composite wheels would be excessive for tractor work, and might mention that we are designing wheels at the present time for a well-known make of tractor, and believe that this will come out at least as light as the present built-up wheels; more
over, it should be borne in mind that complaints have been frequent of late of the noise and dead-runningof heavy motors of the tractor type in large towns, and we are confident that some form of composite wheel will be found indispensable if the complaint is to be overcome.
In his description of our Samsonian wheel, Mr. Markham is not quite clear ; the hub is insulated from the wheel by a wooden cone (not wooden wedges) and this is tightened up by means of the nave-plate bolts which force the cone further into the wheel as it becomes slack through shrinkage, moreover the wooden block can be renewed at a minimum of cost, and what is very important to owners of wagons with existing wooden wheels, their present hubs can be used. We trust we have not taken up too much of your space.— Yours faithfully,
THE ATLAS ENGINEERING COMPANY. H. CARTER, London Representative,
r, Piccadilly, W., 1st May, 1908.
Acts and Regulations.
The Editor, " THE COMMERCIAL MOTOR."
Sir :--Your correspondent " W.W." (page 251) will find what he requires, in " The Law Affecting Motorcars," by Lucas and Crane, published by Reeves and Turner, Chancery Lane (price 55.). For its small size, this book is very complete, giving, besides the text of the various Acts and Regulations, a summary of the Laws, on motor and other road traffic, extending to too pages. Both Statutes and De
cisions are also quoted.—Yours, etc., " TRAILER." Glasgow.
[We doubt if a five-shilling book will meet the views of our correspondent "VT, W.." although the pace is really very low for a legal production of the kind.—En.]
Suggestion for a,New Service.
The Editor, "THE COMMERCIAL MOTOR."
Sir :—Lately, in taking "THE COMMERCIAL MOTOR," I have found several interesting letters about interiors of motorbuses. Someone from Bethnal Green says that the Great Eastern buses are the hest, and I quite agree with him. For my part, I should like to see them in Brixton, and I think, if they ran to the George Canning Hotel, which is the top of F.ffra Road, and soy to the East End, via Charing Cross, they would pay well. I should be pleased to hear that the Great Eastern is coming : perhaps you would be kind enough to suggest it to the above company.—
Yours truly, " A BRIXTONIAN."
[The manager of the Great Eastern London Motor Omnibus Company will see this letter.—En.]
A "Better Type" of Driver.
The Edifer, "Tux COMMERCIAL MOTOR."
Sir :—I have read with undisguised pleasure " Mick's " letter to Mr. P. Frost Smith and the answer published in No. 164. I know Mick and I know Mr. P. Frost Smith ; hence the pleasure. Re the merits of the " Auto-mixte," I would rather leave that to abler critics; but, there is one part in Mr. Smith's letter on which I would like to add a few words, viz., the motorbus driver's intelligence—or lack of it. Mr. Smith despairs of ever getting a " better type " of driver Under the present system, L am inclined to agree with him, but can Mr. Smith or any other large employer say that he has conscientiously tried to find the new type? My experience of Mr. Smith is that he has a very fine selection of the best type of horse-bus converts.
Has Mr. Smith ever given " outsiders " a genuine oppor
tunity? My experience is that, unless one has driven a horse bus, or been a fourth-rate fitter's mate, one may AS well stop at home as try to convince gentlemen like Mr. Smith that there are a better type about. I was a conductor on one of the first motorbuses that Mr. Smith's employers ever had. I gained a lot of experience, as did the drivers, on the road. This Was an insight into the early Daimler and Straker days. In time, I went to a much larger company, being mated to a clever little leading driver, and I have many times helped practically to rebuild a Scheibler car. After that, another Daimler dose, to be followed by a De Dion experience. I do not wish to brag, but, with the above experience, and a library of technical books, every number of your paper and of its sister journal " The Motor," I hope that you will believe me when I say that, in a minor official's capacity, I can put a good many new drivers to rights. The old ones I leave to themselves, as it is not part of my ethics to be a prig. Do you, think that Mr. Smith's or any other company would give me a chance of showing a sample of higher intelligence on the box-? No fear ! From personal experience, I am afraid that Mr. Smith and all " the others" would show me the nearest way to the door.—Yours faithfully,
"A GENERAL-TILLING-VANGLIARDER. ' ' London.
Friction Transmission for Cabs.
The Editor," THE COMMERCIAL MOTOR."
Sir :—In your most comprehensive Cab Number, of 3oth April, you have been kind enough to mention our system of power transmission through frictional surfaces, and by this we are very complimented. We would, however, dispel an erroneous impression that the non-technical reader might obtain upon reading your remarks in the third column of page 24oa.
In the first place, with our arrangement of gear selection, it is unnecessary to have any adjustment of the selector gear ; if suitable arrangements be made, such as the "Autoloc " control, the whole of the travel of the gear lever quadrant is available and every point in this travel is a gea,r selection. Usually, we lit six definite forward positions of the speed lever, but this is a matter of convention and convenience rather than of necessity : there is no definite adjust_ ment necessary. All that the change speed has to do is to swing the driven, leather wheel across the face of the driving disc. No question of adjustment enters here, as the driven wheel shaft is held rigidly in its four ball bearings and the driving disc is continually engaged by a straight effort of the coiled, " clutch " spring. We claim the maximum of simplicity ; the necessity of adjustments does not conduce to simplicity of construction. In another paragraph you opine that the friction type of transmission is wasteful of power in hilly districts. A very natural supposition upon a cursory survey of the system. However, in actual practice, we have found this not to be so, owing to the intimacy and simplicity of the engaging surfaces and the positiveness of our clutching pressure. We have climbed gradients sharper than are ever likely to be met with on ordinary cab service and this with a gear ratio double as high as the standard " Certus " cab is geared. We have done this with a side-entrance car weighing 1+ ton and fitted with the same two-cylinder to-12h.p. engine as on the cab chassis and geared to 42m.p.h. on the level. During these climbs, the engine was doing its full work and running at such a speed that one could count the beats of the explosions. This conclusively proves that there could be no slip taking place in the gear, hence there can be no waste of power on hills (or anywhere else). [What about end-thrust when wear has taken place?--En.]
We are at any time only too pleased to demonstrate to anyone interested the efficacy and efficiency of our transmission system as applied to motor vehicles.
Trusting we are not encroaching on your space.
We are, dear Sir, yours faithfully, THE " CERT1PS " (GEARLESS) COMPANY, LTD, Dr. I'VTACKENZIE 48a, Gillingham Street, Eccleston Square, S.W.,