Telescopes to Turbines
by Garrett Scaife
Members of the Parsons family made significant contributions to the development of science and technology during the nineteenth and twentieth centuries. WilliamParsons (1800-1867) had his home at Birr Castle in Offaly and became the third Earl of Rosse. Three of his four surviving sons became engaged in engineering enterprises. The youngest was the inventor and businessman Charles Parsons (1854-1931) and his working life was spent at Newcastle upon Tyne on the northeast coast of England.
William Parsons created a workshop and foundry at Birr, and trained his own workforce in a town far removed from a major industrial centre.
Like his father and his own sons, he was a university graduate. He brought a thoroughly scientific approach to his twenty-year programme of research. Because of this he was able to manufacture mirrors for reflector telescopes, which were not exceeded in size until 1917 and the Mount Wilson 100 inch telescope. Step by step he mastered the manufacture of bronze mirrors of 24 inches, 36 inches and finally 72 inches in diameter. He perfected the process of grinding and polishing with a steam engine that he had built himself. He rounded off his work by building mountings for the 36 inch and the giant 72 inch mirror.
His reward for this engineering effort was purely scientific. He succeeded in unveiling for the first time, details of the spiral nebulae. In the days before photography had developed sufficiently to allow time exposures, only his giant mirrors were capable of providing sufficiently bright images of such objects for them to be sketched by observers. Spiral nebulae are now known to be galaxies like our own Milky Way, containing billions of stars like our sun, and they are still being intensively studied with the orbiting Hubble telescope, which is unhindered by the earth’s atmosphere.
As a scientist of international renown, William Parsons was elected President of the Royal Society. At home he foresaw the likelihood of a great famine and took practical steps to mitigate its impact. He wrote a thoughtful analysis of the causes of rural poverty. He employed university graduates to operate his telescopes and help to educate his children, engineers and scientists who later made their mark in life. He brought his wife and children with him sailing on long voyages around the north of Scotland and as far away as Spain. He was able to get “stuck in” to a job with his workers. One visitor described seeing the “noble Vulcan” in his workshop being showered with sparks as two smiths hammered on an anvil nearby, while he was rolling up his sleeves to wash his arms after a spell at the workbench.
His eldest son Laurence (1840-1908) continued his astronomical work. His main achievement was a successful measurement of the temperature of the moon’s surface using its infrared radiation. When his younger brother set out to revolutionize marine propulsion he served as chairman of the commercial enterprise which was set up to bring this about.
Both the younger sons Clere(1851-1923) and Charles followed careers in engineering. The normal route for those who sought to become engineers in England was to serve an apprenticeship. For those who could afford it, the fee was around £500 – say £50,000 in today’s money. Normally the total `third level education’ was gained at local evening classes, but Clere graduated from the Engineering School at Trinity College, while Charles studied mathematics at the University of Cambridge. When Charles Parsons set up his own businesses, he employed graduates, and this use of personnel who were scientifically competent played an important part in the success of his businesses. It was in marked contrast to the policy followed by many English firms in the north-east coastal region which relied on apprenticeship for training.
While still a student Charles began development of a unique steam engine in which the cylinder block rotated at high speed. Although it was not a commercial success, the patent described for the first time how oil under pressure was fed to the big end bearings through passages drilled in the crankshaft. This is still a feature of all modern car engines. As an apprentice at Sir W.G.Armstrong’s giant works at Elswick, Charles also developed a torpedo, or `missile’ in modern parlance. It was powered by rocket fuel (gunpowder) that provided gases to drive the combined turbine and propeller. It too was a commercial failure; gunpowder burns unpredictably!
Many pioneers had built steam turbines before this, but none that were practical and efficient devices. When Charles joined Clarke Chapman in Gateshead in 1884 as chief electrical engineer, he set about changing this and succeeded in building a practical machine in just one year.
Turbines show to best advantage in machines of large size. After five years of development he had a conflict with his partners and broke with them and in the process lost the right to use his patents. Undeterred, he established his own firm and built radial flow machines that were not dependent on the 1884 patents. He developed the design so that it could exhaust to a vacuum. This gave a large jump in thermal efficiency. In 1894, having pushed up output by more than 250 times to 1,600kw, Parsons recovered his original patents, but he was now being challenged commercially for the first time by the Swedish graduate engineer CGP de Laval with his rival design.
Clere had received a prize for work he had done as an apprentice, to improve centrifugal pumps and screw propellers. His brother Charles, in his 1884 patent, looked forward to using the steam turbine to drive a screw propeller for ship propulsion. But propeller speeds were typically below 100 rpm, very much slower than turbines. In 1893 he assembled financial backing to build a 100 ft vessel and fit it with a turbine capable of 2,200 HP at 2,000 rpm. Initial results were bad, the maximum speed was only 22 knots, and so he used models to research propeller behaviour at high speeds.
He abandoned the radial flow turbine, and power was directed to three shafts instead of one. As a result, the vessel, Turbinia reached a record speed of 32.8 knots and startled the world’s navies invited to Queen Victoria’s Diamond Jubilee review at Spithead in 1897. The first two turbine powered warships sank for reasons unconnected with their engines, but by 1904 the Admiralty had decided to adopt turbines for all its warships. Other countries quickly followed including Japan. The railway companies had already adopted the turbine for their ferries. In 1907 the Cunard line built the Mauretania, which remained the fastest liner on the north Atlantic until it left service in 1929. In 1911 Parsons successfully introduced mechanical gears to make a better match between turbine and propeller speed. His invention of `creep’ in gear cutting was a major improvement.
While still at Clarke Chapmans, Parsons had begun to experiment with high pressures, at first to make better carbon rods for arc lamps. However, he quickly began to use an electric current to reach very high temperatures as well as pressures with the aim of making synthetic diamonds. After great expenditure of time and money he had to admit that he was mistaken in the belief that he had succeeded. But the methods he pursued were essentially those that are used at present in industry. In 1921 he took out a patent for creating very high pressures by imploding a hollow lead sphere using an outer layer of explosive. It is one of the two methods chosen for detonating nuclear weapons.
Eventually marine turbines were ousted by diesel engines. But steam turbines driving alternators still remain the chief source of the vast quantities of cheap and reliable electricity upon which modern society is reliant. Parsons built the world’s first turbo-alternator in 1890. Before he died in 1931 Parsons’ firm had delivered machines delivering 50,000 kw. In 1911 he was knighted and in 1927 he became the first engineer to be honoured with the Order of Merit. Late in his life, Charles Parsons became involved in the industrial development of optical products when he acquired the business of the Dublin telescope maker Sir Howard Grubb in 1925, having already acquired a firm making optical glass and another making binoculars and similar equipment.
A large part of his income came from licences to use his patents. Parsons was a successful businessman, although he was a difficult person to work with and he treated his factories as large scale workshops in which to perfect his turbine designs. This was a significant factor in allowing him to continue to contribute to the development and perfection of steam turbines. The long-term success of his companies also testifies to the advantages that can accrue to an owner and manager who is both technically competent and scrupulously honest in his business dealings.
Dr Garrett Scaife, Chartered Engineer, is a Fellow and Associate Professor, Trinity College.
From Galaxies to Turbines: Science Technology and the Parsons Family, Institute of Physics Publishing Price £35.00 ISBN: 0-7503-0582-7