Karl Baumann (1884-1971), of Metropolitan-Vickers
1884 April 18th. Born in Hendchiken, Switzerland
1929 Chief mechanical engineer of Metropolitan-Vickers
1950 Retirement announced
1971 Obituary [1]
Dr Karl Baumann, CBE, DSc (Honorary Fellow) of Ilkley, died on July 14. His early life and education are described in an interview published in the CME (Vol. 11 1964). He studied under Prof Stodola in Zurich and became his assistant for the year following his course. After a period with MAN at Nuremberg as turbine research engineer he joined British Westinghouse at Trafford Park where he remained for the rest of his working life. At the time of Baumann's arrival, there was no other turbine design engineer but he was encouraged to build up a staff which, at the time of his retirement, included about 100 engineers and 200 draughtsmen.
Towards the end of 1910 a promising young man joined Baumann's staff, H. L. Guy, later Sir Henry Guy, FRS who, in 1942 became Secretary of the Institution. Another gifted man who worked closely with Baumann was R. W. Bailey, later also an FRS and President of the Institution. Bailey was not formally on Baumann's staff, but played a major part in certain designs and became Baumann's principal adviser on materials.
Baumann's fertility of invention is shown by the 115 patents in his name. A number of these are of fundamental importance.
To power plant engineers today it may seem surprising that feedwater heating by tapped steam was not used in 1915 and that its use did not become widespread until 10 years later. The theoretical benefit of multistage feedwater heating was pointed out in 1884 but the combined efficiency of the boiler and economiser would fall if the temperature of the feedwater to the economiser were raised sufficiently. Baumann proceeded to calculate the performance of the power plant as a whole in a way which no previous designer had done. He detailed the boiler characteristics and took varying load into account. The results of his 1915 calculations are deposited in the Institution Library. They showed that substantial improvement in station thermal efficiency could be obtained by single-stage feedheating with tapped steam. Later, he showed that still greater improvement could be obtained by two or three-stage feedheating in conjunction with boiler, economiser and air heater. More advanced steam conditions with modified boiler designs would justify even more elaborate feedheating arrangements.
Second in importance is Baumann's invention of the multi-exhaust system, patented in 1916. An over-riding problem in the design of high-pressure condensing steam turbines is to cope efficiently with the enormous volume expansion of steam. In the Baumann exhaust, exhaust,area is provided on the outer tier of blading of the penultimate stage, as well as over the whole blading of the last stage, an increase of up to 60 per cent. A single-flow turbine can therefore be rated much more highly and in a multi-exhaust LP turbine the number of exhausts can be reduced.
The performance and reliability of Baumann's turbines speedily justified the Company's decision to change to the impulse type. There was rapid increase in rating and steam conditions. His were the first commercial sets to use steam reheating they were tandem, with separate HP and LP cylinders, triplex Baumann exhausts and three-stage feedwater heating. Baumann's responsibilities also included industrial and marine steam turbines, feed heaters, condensers, reduction gear, air compressors and other items.
Many problems arose in the course of his pioneering work, for example on blade performance, vibration, castings, forgings and creep, which cannot be discussed here. Baumann's versatile mind and qualities of leadership showed to outstanding advantage in coping with them.
After the outbreak of war in 1939 other developments needed Baumann's attention; the most notable was a gas turbine for aircraft. The F2 jet engine was an axial-flow compressor as proposed by A. A. Griffith of the RAE which was flight tested in 1943. Baumann designed the F3 ducted-fan augmentor for the exhaust of an F2 engine. The augmentor was manufactured as a private venture. Its misfortune was that it came 15 years before its time. The simple jet was better suited to military aircraft and civil aircraft had a long way to go before requiring it. When by-pass engines were developed the front-fan type was chosen.
Later Metropolitan-Vickers developed the Beryl and Sapphire jet engines, based on the F2 characteristics. Baumann not only exercised general supervision but also took detailed interest in the design. His noteworthy contributions to the Sapphire included the compressor rotor construction of high-tensile steel disks, welded rim to rim, and the radial pin mounting of the turbine discs.
During the war Baumann also devoted much attention to Naval gas turbines. The world's first gas-turbine propelled ship (MGB 2009) went to sea in 1947. The experiment was successful and orders were received for later Naval designs. After the war, development work was started on gas turbines for land and locomotive application. These were not adapted from aero engines but were specially designed under Baumann's guidance.
Baumann combined in a remarkable way the capacity for seeing a problem in its context with scrupulous attention to detail. He was not a 'committee man'. Except for his publications, he played no great part in Institution affairs. As a member of his staff for 24 years I recall that Baumann was always considerate and generous to his assistants, and gave them every encouragement. I had the utmost admiration for his character as well as his abilities.