OPINIONS and QUERIES Safer Braking for the Articulated Vehicle.
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The Editor, Tat COMMERCIAL MOTOR.
[32181 Sir,—With reference to the regulations of 1929 for the construction of articulated vehicles, although this regulation was made under a repealed Act, it would appear to be kept alive by a provision [S.122 (2)]. Clauses 3a and b of this Regulation appear to deal with the braking of articulated vehicles, and to my mind give rise to a very interesting point.
These two clauses are as follow :— (a) Where the trailer has not more Than two wheels In contact with the ground, the total weight borne by those wheels of the heavy motorcar upon which the brakes of the heavy motorcar act, shall at all times exceed the total weight borne by the wheels of the trailer.
(b) Where the trailer has more than two wheels in contact with the ground, the total weight borne by those wheels of the heavy motorcar upon which the brakes of the heavy motorcar act, shall at all times be not less than three-quarters of the total weight
borne -by the wheels of the trailer.
All vehicles, whether articulated or otherwise, have usually two or three brakes fitted, but in each case there is usually one brake which may be called the principal or •reallyeffective brake, and in this regulation it seems -to be definitely assumed• that the effective braking is going to be carried out upon the wheels of the heavy motorcar, presumably on the driving or centre axle.
A further apparent assumption is that if there was a greater weight put on the tail of the vehicle than on the driving or braking wheels, the braking wheels would skid earlier because of the lesser weight, and on a wet road the tail of the vehicle, or trailer portion, carrying the greater weight would be inclined to swing around.
On all the experiments I have carried out I have found that the ideal point for braking on the articulated vehicle is on the rear trailer wheels, and when brakes are being applied both on a heavy motorcar and the trailer portion, these trailer-wheel brakes should be applied first, and they should be the most positive and effective brakes.
It will be obvious that by braking on these trailer wheels it would he impossible for the vehicle to fold even on the wettest road, as the weight of the heavy motorcar or front portion of the vehicle is always pulling it forward and keeping the vehicle in a straight line. This would particularly apply in the case of an articulated vehicle where there are, at the rear, more than two wheels on the ground, which would allow the fitting of additional brake drums.
To make these brakes effective, however, at least 50 per cent. of the load carried should be supported by this rear trailer axle.
These remarks would apply particularly where vacuum or pressure braking is used.
My contention is, therefore, that braking on the wheels of the heavy motorcar is, and always will be,
dangerous, and a regulation prohibiting the carrying of too much weight on the tail of the vehicle or trailing wheels is certainly not curing the evil, but is apparently preventing the construction of a properly designed vehicle braked in the manner which I have described. I am putting this point forward as a matter of general Interest, and I think it will be most useful if you could obtain the views of . your readers on the point. CHAS. .T. 0. BoucnEu, A.E., Manager. London, S.W.4. For CHENARD-WALCKER TRACTORS.
A Show Suggestion to Help Overseas Trade. The Editor, THE COMMERCIAL MOTOR.
[3219] Sir,—It is a truism that the onlooker sees most of the game, and as we shall not be exhibiting at the Motor Show this year it enables us to review the Show and its objectives in a detached way. The main objective of the motor manufacturers is to display, advertise and sell their cars in the home market, and attract, if possible at the same time, business from the " foreign markets.
• It is on this question of foreign business that I would like to speak.
• The motor industry has developed, of recent years, . into big production„ but its foreign sales are very small as compared with the sales in the protected market at hon-n. Now, other manufacturers, such, for example,
• as gas engine. manufacturers, _makers of furniture, electrical components, 'etc., all exhibit together under the roof of the British Industries Fair and take advantage of an extensive advertising scheme which extends to all corners of the globe.
I therefore suggest that it would be to the advantagq of the motor industry either to join forces with the British Industries Fair or to have its Show running at the sa te time as the Fair. By doing this, I feel sure that the home trade would be equally well served and the export trade would be increased.
I think, however, that before anything of this kind can be done the British Industries Fair should re-consider the date of the Fair. February is about the worst month of the year in England, so far as climate is concerned, and there is no doubt that this factor prevents many foreigners from coming to England at that time. Why, not choose one of the months when England is, without doubt, one of the pleasantest parts of the world to be in? C. Omit, HILL.
Birmingham. Director, For THE COUNTY CHEMICAL CO., LTD.
Hauling for a Builder.
The Editor, THE COMMERCIAL MOTOR.
[3220] Sir,—I would esteem it a favour if you would send me your Tables of Operating Costs. My vehicles are a one-tonner and a 30-cwt. model.'
I am in rather a difficulty with regard to a job (not a contract) that I am starting for a builder. The best example of the work I found in your issue of June 3rd, 1930, under Problems of the Haulier and Carrier, but it hardly suits me, as, for instance, the MS week before last I covered 231 miles with time 27i hours, whereas last week I ran only 200 mile § in
hours, the difference in time being due to loading. • At present I am basing my charge at 6d per mile, hut am having soine difficulty in explaining how the bill for just over half a week is more than for a full one; and then, on the other hand, if I charge by time I do more mileage for half the money.
I do not know if you can assist me in this, but anyway I will take this opportunity of thanking you for the valuable information on all matters which I have
found in The Commercial Motor. BUILDING. . Basingstoke.
[I quite appreciate your difficulty and, as a matter of fact, your real answer to the objections raised by your customer is that the work you do in half a week is barely profitable, whilst that which takes a full week does not pay you. Your actual charges should be based on a combined hourly and mileage rate. You should charge at leat 2s. 6(1. per hour and 3d. per mile for the one-tonner and rather more for the 30-cwt. machine.
On that basis the work which takes you 27i.hours and involved 231 miles of funning shonld be charged at ffi 6s. 9d. At Present you make only £5 15s. 6d. The bther job, 47i hours and only 200 miles, should be charged at £8 9s. and not £5, which, if you will pardon my saying so, is an absurd rate.-8.T.R.] London, to Oxford with Fresh Fish.
• The EditOr, THE COMMERCIAL MOTOR.
[3221] Sir,-I have read with great interest the -various letters and articles in The Commercial Motor, and as ',propose purchasing a 5-ton lorry for bringing fresh fish from the London market to Oxford I should ranch aPpreciate your advice on the matter. I intend to do general haulage as well, making Oxford my centre; so I would be obliged if you would give me a rate per ton per mile for both kinds of work. *11
Will you please enclose with your reply a copy of your Tables of Operating Costs for future guidance; and, further, if there be any periodical, or agency, which might be of some assistance in obtaining loads or contracts I would deem it a great favour if you would supply the names of Filch. FISH HAULAGE. Oxford.
1[1 calculate that you will do 550 miles per week on your London-Oxford journey and possibly a further 250 on sundry work, making 800 in all, and you must obtain from 11d, to is. per mile to make it pay. Your revenue from the London-Oxford trip must therefore be £5. That is equal to £1 per ton, if you are loaded only one way, or 10s. per ton loaded both ways. You should endeavour to get about 15s. per ton to cover journeys run empty.
A copy of the Tables of Operating Costs has been sent to you. There is no periodical or agency which I can recommend as being likely to be of much assistance to you. inobtaining such loads. The only satisfactory way, is personal canvass in Oxford, in the fish markets in London and wherever else opportunity offers.-S.T.R.] The Transport of Provender.
The Editor, THE COMMERCIAL MOTOR.
[3222] Sir,-As a regular reader of your journal T would be glad if you could give me some advice on the following. I have had an offer of a contract for carrying 50 tons of provender per week to a distance of 40 miles at the rate of 10s. per ton, with very little pro-. spects of a return load. I would be glad if you would advise me as to what kind of vehicle to use and whether you think the contract is worth touching, also the costs of running the particular vehicle. Wishing your paper every success. CARRIER. Liverpool.
[The reply to your question turns on your prospects of using whatever vehicle yon buy for other purposes, supposing that you obtain one big enough to enable you to carry this 5o tons of provender and still leave time to do other work.
For instance, if you were to buy a 5-ton lorry, then, cart, ing two loads per day, it would take you all the week to do the work. Your mileage would be 800, and your cost of operation £32, or nearly 13s. per ton. If you were to use B44
an eight-tonner, then, with an occasional slight overload you could carry the 50 tons-in six journeys, doing ,4r miles in three days and leaving you a couple of days on which you could do other work. SuPpose' youmanage 120 miles of Other work, your weekly. mileage would be .600 and your total cost again about 132. Your revenue from the 50 tons at 10s. per ton would be £25, and if the other,work would bring you a further 112414, the work would be profitable.
If you used a 6-ton lorry and trailer carrying 10 tons at a time, you would just: about make your cost ,of operation from this contract, but you would be fully engaged for five ,days in the week, with no margin for profit. The price quoted is hot ope which is-ordinarily regarded as remunerative unless theie. are prospeCts of return loads at least every other journey," and I should not advise you to take it up unless you Can discover such prospeets.-S.T.R.] Running a Six-wheeler conversion.
The Editor, Tyra COMMERCIAL MOTOR.
[3223] Sir,-I have-just purchased g new Ford 70cwt. six-wheeler for general haulage work, and not having had experiences in the &:sts, etc., I am doubtful as to what charges to make to cover all expenses and a wage of, say, £4 per week.
I would be obliged. if you could suggest, as an example, how much per ton to charge on a load of 70 cwt. on a journey of 424 miles; also on a journey of 212 miles, returning empty. Would this, reckoned out at so much per mile, hold good on all 70-cwt. loads?
Clayton-le-Moors. C. ARMITAGE.
[Itl" always very diffident in dealing with inquiries about hybrid vehicles. You may take it, however, that your cost of operation will approximate to Bid, per mile and you should get at least lid, per mile run to make a minimum profit. That is equal to about £19 10s. for the 424-mile journey, and you must obtain, say, £20 a time whether loaded or light If there be no prospect of a return load on alternate journeys, then you should arrange your costs so that you obtain £40 for two round trips. As you have only three loads on those two round trips you need £13 6s. 8d. per load. Try to get £15 to cover contingencies. -8.T.R.] • • Contracting for Short-distance .11aulage..
The Editor, THE COMMERCIAL MOTOR:
[3224] Sir,-I am writing to ask' you to work out the
• following tender and kindly to answer Me through the columns of The Cogimercial Motor. I have taken the
contract as under :• Approximate Mileage. . Price per Ton.
Two miles return ... .„ is. 9d.
Four miles return ... 3s. Od.
I. have to travel, now and again, amatter of three miles return with my machine unladen; also I have 3d. per note for weighing.
employ a 30-cwt. Ford on the job and anticipate between 30 cwt. and 2 tons as each load, also the contract is not full-time work, calling for an average of
2i days per week. CURIOUS. Barnsley.
[You do not tell me what sort of material it is you have to handle and therefore you leave me in the dark as to the time taken to load and unload. I assume 20 minutes each.
For the two-mile haul (I take it you mean two miles each way) the length of time will be 50 minutes and the mileage four. For the four-mile haul the time will be one hour and the mileage eight.
Your actual cost of operation will be 94s. per week, practically 2s. per hour, and 3d. per mile. To make a gross profit of 1s. 6d. per hour, and that I regard as a minimum, you must charge 3s. 6d. per hour plus 3id. per mile.
On that basis, for the two-mile haul you will charge 2s. 11d, plus is. 2d., which is 4s. 1d. Add 3d, for the weighing machine note: total 4s. 4d., so that you should obtain from 2s. bid, to 2s. 2d: per ton, according to how the load varies from 30 cwt. to 2 tons.
On the four-mile haul you must charge 3s. 6(1. plus 2s. 40., which is 5s. 104.: add 3d., making it 6s. 1c1., which is from 4s. Id. to 3s. Oid. per ton, again according to the load.
There is allowance in the 3id. per mile for the dead mileage to which you refer.--S.T.R.]