HINTS FOR HAULIERS.
Page 39
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An Occasional Chat on Subjects and Problems of Interest to those Who are Engaged, or About to be Engaged, in Running Commercial Vehicles for a Living.
0 E THE three items of running costs which, as I indicated last week, it is necessary to make daily records, those of fuel and oil present least difficulty. For the time being, I will deal with petrol vehicles only, leaving the steamer and the electric for consideration later. It is, above all necessary that we should be systematic, and if the records are to be always right, then we must start right. I will consider fuel first.
The simplest way perhaps would be to debit each vehicle with the quantity of fuel which is poured into its tank daily, so that, at any time, by totalling the amount supplied and also the mileage covered, the actual fuel consumed per mile, and, therefore, the cost per mile for that fuel,could easily be ascertained. The figures thuseobtained, however, would only be sufficiently accurate if the period of running covered was a fairly long one, so long that the effect on the result of any quantity of petrol which might still remain in the tank, otherwise unaccounted for, would be negligible. I will explain.
Suppose we have a four ton lorry, in connection with which entries have been made acoording to this schedule. Let us assume that the period it has run covers three months, and that the actual mileage in that time is 6,500. It is more than likely that somewhere about 1,000 gallons of petrol will have..tieen justi
fiably into the tank. At any rate, we may take 1,000 gallons as a fair round. figure for the consumption. If we just calculate our mileage• and fuel costs on this basis, we arrive at 6.5 miles per gallon as the consumption andees08d. as the running cost per mile for fuel alone. Now if, as a matter of fact, there is actually 10 gallons of petrol still remaining in the tank, then, on the assumption that we started with an empty tank, we have in reality used 990 gallons only and our figures are incorrect to the extent of 1 per cent. Really the mileage per gallon is 6.57 instead of 6.5 and the running cost for fuel is 6.01d. per mile instead of 6.08d. The difference is not great and would be less and less as time went on. The biggest possible error in any case would be in a full tank of petrol, say, 20 or 30 gallons.
The Importance of Avoiding Errors in Computation.
Now let us see what would happen if a similar mistake were to be made over a week's running. Assume the same vehicle, running 300 miles in a week, during. which time 60 __gallons of petrol have been poured into the tank. On the assumption that all those 60 gallons have been used, the mileage per gallon of fuel is 5, and the fuel cost per mile 7.9d. If, now, we assume again, that at the end of the week there are 10 more gallons of petrol in the tank than there were when we started, the consumption and cost figures become 6 miles per gallon instead of 5, and 6.6d. per mile for fuel instead of 7.9d., a difference of more than lid. per mile. It may be urged that, since no figures of running coats are really valuable until they have been collooted over long periods, this defect of the simple method of recording is not an important one, which it perfectly true. On the other hand, however, since we have made up our minds to enter these items up daily and weekly, they may just as well be done properly all the time particularly as the extra trouble involved is not great. Moreover, a weekly cheek on the fuel consumption of every vehicle is very useful in more directions than one, and not least
because it enables the owner very quickly to detect any unusual over-consumption which may be due to waste or inefficient working of the mechanism of the chassis. In this connection, it may be worth while to point out that a saving of half a mile per gallon of fuel, in the case of a vehicle of the same size and type as that we are discussing, which travels 500 miles each week, is equivalent to an economy of approximately 8 gallons a week or 26s. That, in itself, I think, is a sufficient inducement to keep these records correct up to date.
The Method of Ascertaining Tank Contents.
It is necessary to know, therefore, at least once a week, how much petrol there is actually in the tank. Preferably, this will he ascertained each Saturday before closing. If the tank is provided with a petrol gauge this figure needs only to be read off from the indicator, although, personally, I should be inclined carefully to check over any such indicator before placing too much, reliance on it. If there is no such fitting, then it will be necessary for the user to make his own gange. and, even 'in these advanced days, there is nothing better than the old-fashioned notched 'stick. This will have to be made by the owner himself, and the difficulty of making it depends entirely on the shape of the tank itself. If a plain, rectangular one, the following process will suffice. Get a suitable stick and trim the bottom end square. Pour two gallons of petrol in and mark on the stick the actual depth. This will be sufficient as a rule to bring the level of the petrol above that portion of the tank in which rounded corners may affect its sectional area. After that the tank may be filled nearly to the top, counting the number of gallons necessary. If a further 18, for example are required to fill the tank, then the depth when full should be marked on the stick and its total length.then divided into 20 equal divisions. These represent gallons, different notches should be numbered off from the bottom, and, if the reader fancies, he may mark it off in half-gallons so as to serve as a more accurate check.
If the tank is a circular one, then the stick will have to be marked all the way up, gallon for gallon, until full: I take it that entries will commence for the first time at the beginning of a, week. As a preliminary, the amount of petrol actually in the tank to start with should be measured and noted. In our blank table, which we shall commence to publish shortly, so soon as these preliminary explanations are completed, space will be left for the entry of this amount of fuel as being " brought forward." During the week, the quantity of petrol poured into the tank each day must be noted, and on the Saturday the quantity remaining must be measured and entered in the, form as fuel" carried forward."
Over lubricating oil it is not necessary to be so . strictly accurate. In any case, it is almost impossible to measure the amount of oil left either in the crankcase or in any other component of the chassis, quite apart from the further complication due to grease in grease cups and so on. All that we can do, in the case of oils and greases, is to enter in their respective columns the amounts supplied to the wagon daily. Subsequent columns will provide for entry of the total mileage, the loaded mileage and the miles covered by the empty vehicle. With Alm item of maintenance I will deal in detail nexe
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