AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

A. J. SMITH

2nd February 1968, Page 120
2nd February 1968
Page 120
Page 121
Page 120, 2nd February 1968 — A. J. SMITH
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

engineering—truck director

and A. P. S. AINSLIE

product planning— truck director, Rootes Motors Ltd.

COMPETITIVENESS of British vehicles overseas has been limited for many years, according to Mr. Smith and Mr. Ainslie, by the legal restrictions in this country on gross vehicle weight and overall dimensions. This situation was significantly improved in 1964, but other countries have since raised legal gross weights and axle loadings and again Britain is at a disadvantage.

Since 1964 a flood of further legislation, and proposals for legislation, has hit the industry and both operators and manufacturers have been required to introduce major changes quicker than is desirable for the best engineering design and business practice. Industry's resources have been directed at meeting legislation and have been diverted from the development of more competitive products and programmes that are needed so urgently in export markets to improve our balance of payments. This will also have a longer-term effect due to the reduction in the life expected for a range of models without major changes.

Mr. Ainslie is concerned that the problems of having to digest the requirements of major items of legislation too quickly should spoil the industry's opportunities of developing export markets in face of growing competition. He cites Japan as the "big threat" to British industry in both sophisticated and unsophisticated markets.

In the more backward countries the preference is for simple vehicles, uncomplicated by the need to satisfy special braking and other regulations, but able to operate under the most adverse conditions of terrain and maintenance. Getting a foothold in these countries could pay dividends when progress creates a worthwhile demand—and the Japanese are adept at creating a maintenance service from raw local labour. International agreement on regulations should be given even greater priority by the sophisticated countries.

The ideal place for the power unit of a truck, in Mr. Smith's view, is under the seat—not under the cab floor which either involves an undesirably high floor or the provision of an equally undesirable "dog house" within the cab. Under-seat engine location offers the best means of providing three-seat accommodation, "either side" access to the driver's seat and well-located controls.

Tilt cabs are a great time and effort saver where fitting labour is in short supply (there is an even greater need for a provision of this kind in America than in this country). It may be possible on some vehicles, however, to avoid the complications entailed with a tilt cab by obtaining access to the engine by far simpler means, thus providing both cost and weight savings, although the ability to do this depends very much on the configuration and reliability of the engine itself.

The practice in America is to operate vehicles in a road-speed range corresponding to the engine performance range between maximum-torque speed and peak rpm. This will be increasingly followed in this country, notably in the case of short-stroke V engines installed in trunking vehicles, to enable smoke-free economy to be combined with optimum journey times.

The future of turbocharging in the UK will largely depend on the success (or lack of it) of the first engine produced in quantity with a turbocharger as original equipment. Turbocharging would offer production flexibility as well as, possibly, reduced smoke emission at high speed, a somewhat better fuel economy and contribute to lowering the noise level. Mr. Ainslie describes the UK truck application of turbocharging as "the great dilemma".

Commenting on power-to-weight ratios, Mr. Smith rejects the bhp/ton yardstick as unrealistic and supports the use of a gradient-ability or acceleration standard in any regulations that may be introduced to set a legal minimum for the performance of vehicles on the road. With the increase in engine size resulting from legislation, he foresees a growing use of multi-ratio transmissions, that is with 10 or more gears, and a reduction in the use of two-speed axles. In his opinion controls for both the transmission and the clutch must be made easier to operate, and there is the possibility that transmission requirements for medium /heavy trucks can continue to be met for some years by an easily controlled and substantially orthodox transmission. He is looking forward with considerable interest to the verdict of users who are evaluating the automatic transmission on heavy vehicletypes in service.

Mr. Smith considers that the load-transfer type of suspension used on 6 x 2s in Europe, particularly in the Northern countries, as against 6 x 4s used in Britain, merits further appraisal.

In assessing future suspension developments, Mr. Smith cites the single leaf spring as possibly the most important contender for general acceptability. Experiments by the company with air suspension have established that its benefits do not justify its cost except perhaps for tankers and trailers. As in the design of a leaf spring it is necessary to balance life against cost.

Light pedal pressure is given by Mr. Smith as a priority requirement of a braking system. A close watch is being kept on the development of anti-locking brakes to supplement the use of load-sensing valves. High cost will rule out the application of a flywheel-overrun type and approval will depend on the development of a low-cost reliable system. The possibility that power-assisted hydraulic brakes energized by a spring-loaded accumulator will be developed is not ruled out. A low-cost, low-weight retarder would be a Godsend in Mr. Smith's view, the electric type being too heavy and expensive.

Designing vehicles for the domestic market to comply with a weight rating that will be strictly enforced will enable standards to be established that give the designer the opportunity to exploit weight-saving measures to the full to the benefit of the operator. Measures that offer substantial weight reductions include the use of high manganese frames (these were originally introduced when vehicles of 3 tons and over were subject to the 20 mph speed limit) and aluminium wheels, brackets and so on. Mr. Smith cites the American cost-effectiveness figures for weight saving which indicate that every lib saved gives increased profitability of $1 a year.

In Mr. Smith's opinion, the application of cost-effectiveness principles by fleet managers will undoubtedly encourage the use of high-quality auxiliaries. The effect will be both to increase the use of those already obtainable and simultaneously to make a wider range available for operators who are willing to meet additional first costs to reduce long-term operating costs.

In assessing the probable influence on vehicle design of the container revolution, Mr. Ainslie points out that to a large extent container size will be dictated by ship-loading practices and that this will of necessity involve the use of 2011 or 40ft containers. An extension of the permitted vehicle length to 15 metres would enable two 20ft containers or a single 40ft type to be carried by road.

Mr. Ainslie adds, however, that a fully laden 40ft container could not be handled within current weight regulations, nor could twoor three-axled rigid vehicles handle a fully laden 20ft container. He notes that there is also a noticeable trend towards using 30ft containers; taking the long view it would appear that the most suitable vehicle for container handling will be the articulated outfit.

Taking into account the latest licensing proposals, it is clear that significant developments in the commercial vehicle field must take place to provide a vital service to railheads and docks.

Tags

People: S. AINSLIE, J. SMITH

comments powered by Disqus