VIII. Oral Practice.

Exercise 19. Discussion points :

1. The stages of the development of land transport .

2. The main kinds of land transport .

3. Advantages and disadvantages of land transport .

Supplementary reading Texts for written translation.

Read the texts and translate them in writing. Use a dictionary

Text D

Efficiency in Engineering Operation

Unlike the scientist, the engineer is not free to solve problems which interest him. He must solve problems as they arise, his solution must satisfy conflicting requirements. Efficiency costs money, safety adds complexity, performance increases weight. The engineering solution is the optimum solution, taking into account many factors. It may be the cheapest for a given performance, the most reliable for a given weight, the simplest for a given safety, or the most efficient for a given cost. Engineering is optimizing.

To the engineer, efficiency means output divided by input. His job is to secure a maximum output for a given input or to secure a given output with a minimum input.

The ratio may be expressed in terms of energy, materials, money, time or men. Efficiency is achieved by using efficient methods, devices, and personnel organisations.

The need for efficiency leads to the large, complex operations which are characteristic of engineering. The processing of the new antibiotics in the test-tube stage belongs in the field of biochemistry. But when great quantities must be produced at low cost, it becomes an engineering problem. It is the need for efficiency and economy that differentiates ceramic engineering from the work of the potter, textile engineering from weaving, and agricultural engineering from farming.

Since output is input minus losses, the engineer must keep losses and waste to a minimum. One way is to develop uses for products which otherwise would be waste.

Losses due to friction occur in every machine and in every organisation. Efficient functioning depends on good design, careful attention to operating difficulties, and lubrication.

The raw materials with which engineers work seldom are found in useful forms. Engineering of the highest type is required to conceive, design and achieve the conversion of the energy of a mountain stream into the powerful torque of an electric motor. Similarly, many engineering operations are required to change the sands of the seashore into the precise lenses which enable us to observe the microscopic amoeba in a drop of water. In a certain sense, the successful engineer is a person always trying to change things for the better.

Text E

James watt

James Watt was born in Greenock, Scotland, and was taught at home. Later he went to Greenock Grammar School.

His technical expertise seems to have been obtained from working in his father’s workshop and from early in life he showed academic promise. His early formal training was as an instrument maker in London and Glasgow.

Watt combined the expertise of a scientist with that of a practical engineer, for later he was not only to improve the heat engine but also to devise new mechanisms.

Watt was interested in making experimental models of steam engines and this marks a historical milestone in engineering development, for they were the first experimental apparatus purposely constructed for engineering research. Watt's early interest in steam arose from experience in repairing a model steam engine in 1764, and in 1765 he invented the separate steam condenser. In 1769 he took out a patent on the condenser in which steam came into direct contact with cold water. That was a milestone by which steam engineering reached its practical and usable form.

In 1784 he took out a patent for a reaction turbine at a time when continental engineers were only considering similar approaches. An improved centrifugal governor was to follow in 1788 and a design for a pressure gauge in 1790.

In the development of the steam engine James Watt represents the perfecting of a sequence of stages beginning with the Newcomen engine and ending with the parallel motion and sun/planet gearing. The latter is said to have been invented by William Murdock but patented by Watt.

In the scientific field watt’s finest memorial, apart from steam engines, is his establishment of the unit of power – the rate of doing work. He coined the term horsepower (hp), one horse being defined as equivalent to 33,000 ft lb/min.

James Watt died in 1819 in Heathfield, after a life of incomparable technical value. Later, a statue to Watt was placed in Westminster Abbey.

Texts for home reading

Text F

THE PIONEERS

Karl Benz (1844—1929), the son of a railway engine-driver who died when Karl was two, studied engineering at the Karlsruhe Polytechnic. After various jobs he set up business, with successive partners in a very small way making two-stroke gas engines of his own design in 1880. Although he is entitled to be called the "inventor of the petrol car" he was reluctant to depart from his original design of belt-driven horseless carriage which sold well in 1890s. Other designers were called in, and after 1902 Benz had little influence on the development of the motor car.

Frederick William Lanchester (1868—1946), the son of an architect, made Britain's first four-wheeled petrol car of wholly native design in 1895 with the help of his brother George. A small company was formed and production was begun late in 1899. Lanchester's designs were always unique and ahead of their time; he was responsible for many innovations which became accepted some years later. Those include a vibrationless, fully balanced engine, splined shafts, full-pressure lubrication, lightweight pistons, disk brakes and more. "Doctor Fred" was also a pioneer authority and writer on aerodynamics, and for many years Consultant Engineer to the Daimler Co.

Henry Ford is usually credited with "inventing" mass production, yet the idea originated many years earlier in the Connecticut clock trade and was developed in the America's small-arms industry.