OPINIONS FROM OTHERS.
Page 20
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The Editor 'invites correspondence on all subjects connected with the use of commercial motors. Letters should be on on side of the paper only and typewritten by preference. The right of abbreviation is reserved, and no responsibity for views expressed is accepted.
Traction by Pull.
The Editor, THE COM PCIAL MOTOR.
[1583] Sir,—I have read the in, •restingarticle which appears in your issue of the 31,it. on the Nilson tractor and its system of "traction by pull." But are
• the inventors sound in their theory'? So far„as I read your article it is undierstood that the object of securing this "traction by pull "--a -similar• result being aimed at also in the Bates "Steel Mule—is to avoid the ground pressure and Consequent consolidation which would be needful if .a sufficiency of weight were pitt into the tractor to secure efficient tractive grip and to
prevent slip" when the pull exceedsnormal.
-What puzzled .me, however, is how vertical pressure on the land exerted by pull can differ in any way from vertical press-Lire on the land exerted by weight. It seems to me that the effect—that is, the pressure— must be the same in either case to secure the same result inefficiency, and, if the pressure .is the same, must not the consolidation:effect be equal ? If this be so, the main object of the inventor in both cases is destroyed. Should, however, the system be beneficial, the net result would appear to be that the undue slip which takes place with.light.tractors under heavy pull might be. eliminated or reduced, and so the need for extra weight in tb.e tractor to provide for the reqiiirements of heavy pull may be avoided. I would be very much interested to have the views of other readers an this "-nest interesting development.—Yours faithfully, •r INVESTIGATOR. Banbury.
Criticism of Agrimot's Spud Suggestion.
The Editor, THE COMMERCIAL MOTOR.
0.5841 Sir,—I read with.interest " Agrimot's" notes in THE COMMERCIAL MOTOR, aiLd should like to comment briefly on his suggested-idea for spud attaching facilities.
The principal difficulty of all spud attachments is no doubt the mud, which is certain to cake all over the wheel. inside and out, and anything in the nature of mechanism is very doubtful of achieving the desired results. The idea, illustrated is no exception; for instance, when a spud was being put on it could not be moved sideways to give the temporary hold owing to mud, which most certainly would be present, and without this hold the spud would, of course, drop off.
The locking ring, I consider, could not ba relied upon to stop in position unless fixed positively or wedged tightly under the spud hook. Another point is that-the ring would get badly rusted up as the result of exposure and would bec_ome difficult to move. From a. manufacturing standpoint, the idea could hardly be entertained owing to the complications and consequent expense, apart from its unreliability. As before stated, anything mechanical would appear to be out of the question. Some years ago I saw a device worked by an eccentric which automatically projected bars or spikes through slots in the wheel rim when the wheel revolved, thus being self-cleaning; but one would imagine that, unless heavily constricted, th,ese proaections would get bent and Jam in the slats if used on hard or stony soil. It is rather curious to note that in the steam traction engine business, including cable ploughing sets, no maker, for the last 40 years, Beems to have been able to improve on the conventional angle iron spud which is hooked at one end to go "round the wheel rim and also held by a bplt and .ecitter. Here, again, it is mud which interferes with fixing the bolt and cotter, and since it is utterly impossible to keen wheels clean on the land the fixing of c48 • spuds or other attachments temporarily is bound to be a long job. To reduce the total number of bolts and cotters on agrimotors, it might be possible to fix permanently several spuds to a plate, embritelp., say, a quarter of the wheel circumference, `and which would, only need three or four bolts. This method would be bulky and heavy to handle... No doubt big improvements will be effected in course of time but at present it presents a problem more difficult to solve effectively than would appear on the surface.
Leeds. . • . • • CECIL II. Cox.
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The Editor, THE COMMERCIAL MOTOR.
[1585] Sir,--We notice that your paper frequently refers to shortage of man power and petrol, bath of which we have felt, but if the general position is as it appears, why is the Petroleum Pool Board allowed to encourage the gross waste of both.
The spirit companies at one time allowed lid per gallon off can price of spirit to bulk buyers. This was little enough considering what bulk deliveries saved them, but it encouraged us to sell to commercial buyers at their proper price, i.e., wholesale can price.
The Pool Board now decree that all spirit for resale is to be charged at can price, commercial users who buy in bulk or barrel to have id. ciff. The wastage from: the barrels used is greater than from cans, and comparatively few of the commercial users apart from the very large companies have a bulk storage system. The relative cost, of can and bulk distribution is as follows :—
Upkeep and filling of cans Cartage from London depot to rail ...
Raal to depot and retailers pramises Rail charged Chelmsford and 'London (full and empty) Cans returned from country depot to London as lea,kers, 7i per cent.,. and assuming that 6 per cent, of the spirit is lost, equals at
Spirit delivered in cans and .accepted as correct will be at least 5 per cant. short if measured, and the wastage in filling into ears, etc., will certaint be not leSs than 1 per cent., which, valuing spirit at the
same figure, ix., as., equals 211.
The cost of delivering by motor tank wagon from London (1000 gallons) to • Chelmsford four tons at ls per ton Per mile one way . (30 miles).equals 120s. or per gallon ...
Theo figures are approximately correct, but there might be large errors without affecting the apparent absurdity of the Pool Board's regulation, and the net effect isto 'encourage the can trade at a Cost of
in labour, 6 per cent. spirit wastage by companies, and 6 per cent, wastage by user who is usually not too liberally rationed. You will also notice that if a motor tank wagon uses one gallon per five miles it will use 118 .011(ms less than is wasted by users:- Yours faithfully, For and on behalf of J. W. AUSTIN'S COIJAITY WORKS, LTD. Chelmsford. .