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Present and Future Trends
CARE has to be exercised in making any comparison between progress in goodsvehicle body design and that of passenger-vehicle bodies. The two have never evolved on parallel lines.
There are too many variants among the factors influencing goodsbody design for trends to take shape as smoothly as is the case with passenger vehicles. All that can safely be said as to common factors is that at the present time there is in both cases some controversy on the question, "composite and craftsman, built, or all metal and jig-built?" . Beyond that, goods-body makers are facing different problems, and are influenced by factors different from those affecting their public service vehicle counterparts.
There is a great amount of traditional goods-vehicle bodybuilding still going on, and following a process of selective improvement, consistently and steadily.
Sound and Simple "We are of opinion that .a sub' stantially built structure of sound wood foundation, with steel or aluminium panels according to size and capacity, with simple flowing lines and of good appearance, will be the general trend in design of the goods-vehicle body of the future."
Such is the observation of Messrs. Reall, of Ealing, London, W.5., who go on to say that the larger type of goods body is essentially the work of a skilled craftsman, and"cannot be successfully mass-produced, because of the highly specialized requirements of users. These manufacturers make a plea for the safeguarding of the existing craftsman and the extension of systems of training.
There are those manufacturers, however, who have decided to break away boldly from the classic form, . and to benefit from the modern • industrial technique of all-metalor nearly all-metal—construction. The most usual form, among these progressive types, is that in which light-metal basic structures of members of various sections are employed, and panelling is usually in a suitable gauge of aluminium sheet. Sometimes the structure is entirely metal, sometimes there are wood bearers, fillers, etc.
• A typical small van body is prefabricated on special jigs on the imit principle, with extruded sections of M.G.5 as the material, and is then mounted on more or less normal bearers on the chassis. Panelling in the same material is done on the stressed-skin principle. Pop-riveting is widely used.
Sections of metal employed range from simple angles to complicated modifications of the hat section. Opinions differ on the best alloys to use, but in any case the choice is often dependent upon circumstances. Good stress distribution allows the employment of softer metals than would otherwise be the case.
Production facilities may demand a metal easily worked without annealing. If panels are to take part of the stresses they must contain sufficient magnesium.
Many advantages are claimed for the light-metal body. The low weight is obviously desirable, not only to get the best out of an onerous taxation system, but to obtain a satisfactory power-to-weight ratio.
Working in metal is in many ways easier than in wood. Durability and rigidity can be greater. Repairs can be carried out more easily and probably more chdeply. All-metal bodies can be spray-cellulosed, instead of painted by brush.
Light Composite Bodies On the other hand, Spurling Motor Bodies, Ltd., states that the composite body of light construction of timber and pressed sheet steel is far more popular than the light alloy body, irrespective of cost. At the same time, sectional construction of units such as roof, sides, floor and bulkheads, to facilitate production, is becoming more widely accepted.
One manufacturer, Kennings, Ltd., Sheffield, states that the increase in the 30 m.p.h. weight limit from 21 tons to 3 tons was an improvement, allowing more robust construction.
On the other hand, Messrs. Real!, Ealing, W.5, contend that it is still too restrictive, and that if the limit were put up to 4 tons, this would enable bodies of sizes required on larger chassis (Luton vans, meat con tainers, boxyans, etc.) to be built as substantially as their cargo warranted.
The latter manufacturers go on to say that comfort .still requires greater attention in goods-body design. Common complaints are that 'ventilation is poor, floor-board tempera tures excessive, vision restricted and seating cramped. Movable seats are advocated.
References to varying trends and practices in design would not be complete without that of J. II Sparshatt and Sons (Southampton), Ltd. In this company's original form of construction, tubes and blocks are employed, something after the style of tubular scaffolding, and joints are electrically welded in
position. Panels are either attached to angles bolted to the blocks or else aluminium panels are used, with wood sections in place of angles Regardless of constructional policy, there is a marked trend, in many cases, towards less conventional and usually more pleasing appearance, According to James Whitson and Co., Ltd., the present tendency towards a clean flowing design in passenger-vehicle bodies must be reflected in goods bodies. Higher cost is paid for by added publicity.
Quoted as an example is a Maudslay Mogul with a special body for brewery cartage work. A fully enclosed cab with sweeping lines has well-upholstered bucket seats. There are full-drop windows and a large roof ventilator The ventilator, when open, enables lifting tackle to be fixed to the engine, which is removable when the front grille is taken off. The vehicle has excited favourable comment wherever it has appeared.
Further reference to special types is provided by Messrs. Wokingham Pantechnicon, who say that in the case of furniture bodies, development can be summed up in the words, "larger, lighter and lower." Cab cornfort, they say, is commanding more attention. Items quoted are adjustable seats, draught-proof doors, air conditioning and better vision.
The double-cambered roof has superseded the single-cambered type. The absence of rooftop loading permits a lighter form of construction to be used. The upper part of the back is closed either with two doors or a panelled canopy. Low valance lines continue to be favoured and the effect on maintenance seems to be discounted. The poster type of decoration is said to be on the way out, giving place to formal layout and classic or modern lettering.
The Jensen lightweight oiler pantechnicon is a notable type. It has an alloy body with corrugated floor having timber inserts. The interior is panelled with corrugated alloy to the waistline and has timber rails above. There is comfortable seating for three in the cab, the design of which has been given more than ordinary study both as to comfort and good visibility.