Light Alloy Bodies Can "Take It" !
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BEFORE the war it was often difficult to persuade operators of goods vehicles of the benefits to be gained by the use of light-alloy bodywork. The higher initial cost of lightmetal construction was a strong deterrent to general employment, despite the advantages of lower operating costs and greater earning, capacity resulting from the reduction of unladen weight.
The evidence, prima facie, was sufficient for the more enterprising spirits of the industry, but the " diehards " often required a greater measure of proof titan the state of experience existing at that time could supply. Moreover, doubts were entertained as to the ability of light-alloy bodywork to withstand rough usage, and timber construction continued in general favour.
350 Lightweight Bodies Since the war, the shortage of wood has compelled operators and bodybuilders alike to adopt a most enlightened attitude towards metal bodywork, and many commercialvehicle users are now enjoying for the first time the virtues that accompany this necessity. The experience of the London Brick Co., Ltd., with about 350 vehicles equipped with Duramin bodywork; should assure them that their choice has been wise.
The company is no new convert to lightweight construction. It is among the pioneer users in this country and its ,faith is thoroughly justified by the results. Costs of operation and maintenance have been reduced, earnings increased and the effects of accidents diminished. In one instance, there is reason to believe that a driver owes his life to a light-metal cab.. The London Brick Co., Ltd., an important operator of A.E.C. vehicles, told me that a Monarch or Matador with a cab and body by the Duramin Engineering Co., Ltd., Standard Road, London, N.W.10, is 5-10 cwt. lighter than a similar machine with wood or composite bodywork. The wood cab and body of Monarch D 69 (the company's code number), a vehicle which weighed unladen 4 tons 1 If cwt. as licensed, was recently replaced by a Duramin structure, which reduced the actual unladen weight to 4 tons Of cwt. This saving of 10f cwt. lowered the annual taxation rate by £5. With . the Mammoth Major, the seduction of unladen weight is even greater. In a recent conversion of a vehicle of this type, the unladen weight was reduced from 6 tons 12 cwt. with a wood cab and body to 5 tons 19 cwt. with a Duramin structure. By this saving of 13 cwt. the vehicle was placed in a taxation class £15 a year lower.
Economy in taxation is, however, by no means the sum total of the financial benefits.
£1,562 Saved 'Take as an example an eightwheeler running 250,000 miles—a figure that certainly does not represent the full life of such a vehicle—and assume that for half this mileage the machine runs light," said the transport manager. "With lightweight cab and bodywork, the operator has the advantage of at least I ton extra payload for 125,000 miles, or an additional 62,500 ton-miles. At 6d. a ton-mile, the additional revenue during the 250,000-mile life of the vehicle is £1,562 10s.
"The higher initial cost of the bodywork is,. therefore, covered many times over. Again, when the vehicle is running, light, there is some saving in wear and tear, although, admittedly, this will be very slight," he added.
The company's experience shows that reduced wear is accompanied by greater strength. " Duramin underframes are notably more robust than timber structures.," the transport manager remarked. "Their life would seem to be almost infinite, as, after 11 or /2 years' running, we have yet to experience a failure.
"With timber-built bodies, the weakest points are usually at the joints. Water enters there and is absorbed into 9 3 t
the timber, which eventually becomes distorted and sooner or later rots.
"On the other hand, our experience with all-metal jobs has proved the joints to be the strongest parts, and they have complete immunity from the Parra of deterioration that I have just mentioned. Bracketing and joints—in fact, all riveting—are as sound to-day, after upwards of 10 years' service, as when originally made."
Personal inspection confirmed that statement.
Except for the periodical checking of
holding-down bolts, little maintenance is requiredby the all-metal cabs and bodies used by the company.
Over a period of 10 years, the actual cost of maintenance repairs (which are almost entirely confined to overhauls) averages about £32 per vehicle. Wood floors of cabs represent the principal renewal charge.
Repairs to Underframe—£3
• Vehicle D 29 has just been completely overhauled at 307,602 miles. This is the first time that the cab has been repaired or overhauled. • The repairs, including the A.E.C. cab structure and the fitting of two new wings, cost £37, whilst repairs to the underframe, including two small replacement brackets, amounted to £3. These two brackets had to be fitted because the holding-down bolts had worked loose.
Repairs also had to be made to the rear cross-member because of accidental damage, but the cost of this item was not included in the overhaul charge. Over a mileage of 307,602, cab and body repairs cost 0.034d. per mile.
"Not bad," was the transport manager's laconic comment.
Paintwork on all-metal cabs has been found to last much longer than on wood or composite structures, and even after five or six years of arduous service, it presents a cleaner appearance. Before the war, all new metal work was covered with a rubber primer, but this material is no longer available, and the company is using zinc-chromate as a substitute.
The longer life of the paintwork is responsible for a further saving In A32
maintenance cost, although it is not yet possible to determine how post-war paintwork compares with the pre-war product.
Drivers employed by the London Brick Co., Ltd., have become keen adherents of the all-metal cab. "No one would claim that the metal cab is free from drumming," said the transport manager, "and .in this respect the timber-built job is at an advantage, but any such benefit is completely outweighed by the greater safety factor of the all-metal structure. "We have experienced several bad head-on collisions, in which metal cabs have saved our drivers from serious injury and, possibly, from fatal consequencies. During the war, one of our Monarchs was in collision with a United States vehicle, which came to rest above the cab of the A.E.C. Had the cab been made of wood, there is no doubt that the man would have lost his life; in fact, he crawled out with nothing worse than.a few bad cuts and a shaking."
Proof of Strength
An accompanying illustration shows the cab of a vehicle which recently left the road and landed headfirst in a deep dyke. It could not be towed out and eventually had to be lifted with giant sheer-legs. The front axle was knocked off, yet when this unit had been replaced, the vehicle was driven into the works for repair. The cab suffered' practically no damage, as the illustration testifies, Since the war, the cost of fimber has risen much more steeply than that of light alloys, and the gap between the prices of metal and wood cabs has been narrowed. The savings to be expected by the use of lightweight structures are, therefore, now even greater than in the 1930s, for the amount -to be earned before the greater initial cost is wiped out is •smaller.