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Simplified Chassis Design Needed
Page 104
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A Haulage Expert of Considerable Experience Gives His Views on Simplicity in the Layout of Commer • cial Motors. The Influence of Recent Legislation on Engine and Braking Design
By C. Le M. GOSSELIN, _M.I.A.E. (President Commercial Motor Users Association)
,
AREQuEs, to'virrite ansartide on simplicity of design of goods vehicles comes to a haulage contractor somewhat in the nature of a bombshell. The Road Traffic Act and all its attendant regulations, temporary and provisional, together with the possible interference with design which may arise out of decisions by Traffic Commissioners in regard to publicservice vehicles, have elevated the whole question of commercial-vehicle -design into something cOmparable with a first-class nightmare.
Jr• must be remembered that the design of the goods motor is largely influenced by that ofthe public-service vehicle.
In the matter of speed limits laid down in the Road Traffic. Act, a further influence will be brought to bear on the type of vehicle which can econonlically be employed . on the road for goods-carrying purposes. Again, the recommendation contained in the Final Report of the Royal Commission on Transport that vehicles exceeding four tons tare weight should be taxed to an extent that will materially affect the possibility of their use is another influence which must control design. .
The Influence of the Road Traffic Act.
Up to the passing of the Road Traffic Act tendency in the design of goods vehicles was to bring them into closer line with that of motorcars—the vehicles were equipped with high-speed engines which could accelerate rapidly, and had braking systems capable of equally rapid deceleration, the speeds attainable by the vehicles being almost equal to those of a moderately powered motorcar.
This policy undoubtedly was tending to make the commercial vehicle a safer unit in a stream of traffic, because as regards performance it could function with efficiency equal to that of other units on the road, but the passing of the Road Traffic Act threatens to call for a different type of vehicle in which maximum speeds must be much reduced and, consequently, braking systems will not require to be so efficient. This must further affect engine design, as it is clear that engines will not be required to run at the same high. speeds.
Indeed, the models of 10 years ago may be more suitable for the new conditions than are the models which have more recently been produced. In order to counteract this loss of effectiveness in operation it may become necessary for users to rely on the ca4 development of the heavy-oil engine in order to reduce running costs, One thing is certain: the possibility of economically carrying goods by road is being lessened by modern legislation, apparently with the set purpose of reducing road traffic and increasing railway receipts.. In order to combat this it will be necessary for manufacturers, as a whole, to consider the possibility of reducing the cost of their products by a combined effort.
At present, the policy of the manufacturers appears to be to make the units of their products non-interchangeable with those of other makers, but there are many parts of a vehicle which could be standardized throughout the industry. Some policy for the massproduction of these parrs will have to be developed— wheels, back axles, gearboxes, steering gears and braking systems are all components which lend themselves to individual mass-production.
pi regard to accessories, manufacturers fail to realize that it is a bad policy to allow the man who has purchased their chassis to be driven into other markets for the purchase of accessories. It should rather be their policy to bind customers to them by making them feel that any subsequent requirement they may have can be met at a lower price from the source whence they originally purchased their chassis.
The Need for Standardization.
That there is need for the greatest possible degree both of standardization and simplicity of design in the case of goods-carrying vehicles is obvious. Publicservice vehicles are usually operated by skilled staffs, with trained engineers in attendance. Goods vehicles, on the other hand, are often employed by commercial firms who make no special provision for maintenance and rely largely upon the skill of the driver to carry out what are loosely termed "running repairs."
Further, goods vehicles are frequently employed away from their base and the whole subject of readily obtaining replacements and the ease with which they can be fitted becomes a matter of prime importance.
It is a matter for consideration whether under existing regulations a six-cylindered unit provides advantages over a four-cylindered engine. The former type is undoubtedly. less economical than is the latter, If due regard be given to accessibility, forward control is preferable, because a better distribution of axle weights is obtained, as well as a greater platform area for the same length of vehicle.
In the bonneted type of vehicle British manufacturers still persist in placing the front axle of the vehicle too far forward, which undoubtedlyadds to the appearance of the machine, but prevents a sufficient proportion of the load resting on the front axle. The outstanding requirement of design, however, is, as has been already stated, a thorough standardization throughout the trade of all parts practicable, not only in the manufacture of the numerous components of the vehicle, but also in the layout of the pedals and levers, which would be of great value to the driver.