That " Nice Work" T OUR article " Nice Work If You
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Can Get It!" (November 7) raises a number of interesting points. On behalf of the National Council of Coal Traders, may I make one or two comments which I hope will help your readers to gain a more balanced picture, As it stands, the article might conceivably give a false impression of the role of wholesale distributors in the coal trade.
The supply of fuel to Central Electricity Generating Board consuming points is a specialized class of coal distribution which few of our member companies have the organization or the equipment to undertake. It would be difficult to believe in these days that the C.E.G.B. would pay thousands of pounds commission to a distributor who did nothing in return.
The buyers are free agents, and they place their supplies in the hands of distributors—whether they be the N.C.B. acting in their capacity as distributors or private-enterprise companies—according to the services required at the many and various consuming points. For the most part, the very substantial tonnage for which wholesale distributors are made responsible is delivered either by coastwise ships for power stations situated on the water-side, or by largecapacity road vehicles for inland consuming points which are non-rail connected or find that regular consistency of supply is best achieved by road vehicle. The remainder of the coal for power-station use, still millions of tons, is bought direct from the N.C.B. and delivered by rail to sidings, whence the consumers themselves undertake the discharge and delivery to boiler house. There is far more than a mere book entry involved in efficient delivery of the bulk commodity. A great deal of expert experience and organization is necessary to arrange loading of the right coals at the right time for delivery according to the consumer's requirements, apart from the substantial capital required to purchase and maintain the equipment and an adequate fleet of vehicles. The same applies to an even greater extent to delivery alongside wharf by coastwise vessels, especially when bargeing is involved.
Finally, the haulage item in coal delivery is a substantial part of the cost, irrespective of whether the delivery is by rail, road or sea. That the Yorkshire distributor mentioned in your article could do this service without "claiming" a charge, is, surely, not logical.
London, W.C.1. A. R. BRUCE,
The National Council of Coal Traders.
Accuracy of Test Figures Queried
BEING a regular reader of The Commercial Motor and of an associated motoring journal, I naturally read with interest road test reports of new vehicles. I must say that some of the figures given in these tests have sometimes made me wonder, as regards their accuracy.
On reading, in your issue of ,November 7, the report on the new Commer 6-tonner, I was somewhat startled to read that John F. Moon had performed the amazing feat of achieving over 100 per cent, deceleration on applying the foot brake. He certainly is right when he follows this by saying that "there was little noticeable lag in the braking system," for over 100 per cent, deceleration will mean that, on applying the brake, the vehicle will immediately be travelling in the opposite direction.
Mr. Moon also achieved the "exceptional efficiency " of 54.75 per cent. with the hand brake "without excessive c24 effort," although one rear wheel was locked. Surely the Commer designers have gone to unnecessary expense in providing the foot brake with servo hydraulics!
However, reading on and finally coming to the road test chart, I note that, according to the maximum stopping distances given at 20 m.p.h. and 30 m.p.h., the deceleration efficiency by my figures gives 53 per cent. and 57 per cent. which is more down to earth and still exceptionally good. Surely this proves that these inertiaor pendulumoperated meters can give very optimistic figures under certain conditions, e.g.., a very soft or flexible front suspension allowing the nose of the vehicle to dip rapidly on brake application, and are of use only when the correct figures are known for particular types, as a comparison. I certainly do not think that they should be used on a new chassis.
Flitwick. J. N. RIDGLEY.
[There is no question of any inaccuracy with regard to the figures quoted in road tests published by The Commercial Motor. Mr. Ridgley is quite corrict in assuming that to achieve over 100 per cent. deceleration with the foot brake is something of an "amazing feat." The instance he quotes is, however, by no means, an isolated example and it has frequently been found that decelerations in excess of 100 per cent, have been recorded by the deceleration meter used on such tests. Indeed, a leader in our issue for October 3, 1958, pointed out the futility of such readings.
A deceleration meter of this type is used on tests only for . comparative purposes, so that some indication of the reduction in maximum efficiency can be obtained when comparing results before and after a brake-fade test, for example. The stopping distances quoted are obtained with a marker gun and represent the distance taken to come to a standstill from the instant that the brake pedal is applied, thus taking into account braking-reaction delay. In the case of the Commer test, it was remarked that there was little noticeable lag in the braking system, and this would help to account for the reading of over 100 per cent. because within a very short time of the brake pedal being applied the vehicle was subjected to violent deceleration which, combined with tht soft front suspension and resultant front end dip (shown in the picture on page 536) would swing the pendulum of the deceleration meter past the theoretical maximum-efficiency figure.
With regards to the figure obtained during the hand-brake test, a deceleration meter has to be employed for such tests because of difficulty in installing the marker gun so that it is fired as soon as the-hand-brake lever is applied. The figure of 5415 per cent, obtained with the Commer from 20 m.p.h. is a quite genuine one, however, although exceptional, and merely serves to indicate that such efficiency can be obtained with a simple hand brake with careful design. "Excessive effort" was not applied: in some cases it is necessary to apply both hands to the hand brake to get anything approaching a reasonable retardation figure, whilst in the case of the Commer a single-handed pull was used on each occasion.—ED.]
Partial Eclipse of the Moon ?
IN his interesting report on the Dennis Paravan (The Commercial Motor, October 31, 1958), JOhn Moon misses an operating point, I think. He says, ". .. at the end of its day's run the payload would have been reduced to nothing."
The usual method of working parcels services is to do deliveries in the morning and early afternoon and then to turn to collections. It is not at all unusual for a van to . return to the depot more heavily laden than when it left.
Birmingham. Ctias. S. DUNBAR.