THE JET ENGINE

20th Century Technology Series

The Twentieth Century Technology Series was planned as an opportunity to look back and reflect on the key developments in engineering and technology and their impact on society and the economy. The five speakers were asked to explain the basic principles behind their respective technology and describe how the technology evolved bringing it up to the present day, then speculate on technological prospects after the year 2000.

Victor Suchar, Series Organiser

THE JET ENGINE

Sir Alex Morris, formerly Chief Engineer of the Royal Air Force, on 23 March 1999

The jet engine is a relatively modern invention yet the principle behind it dates back over 2000 years, for Hero of Alexandria constructed a simple steam jet engine in 150 BC which was more a novelty than anything else.

Eventually Sir Frank Whittle was given a patent in 1930 for a notional gas turbine engine, and in 1943 an engine based on the patent was tested in flight. It took less than 18 months before a production version of this engine was flying operationally in production Meteor aircraft against German V1 flying bombs. This induced an urgency in the pattern of development of the jet engine which revolutionised aircraft design, producing much higher speeds, higher altitudes, smoother power and greater economy in flight costs.

The original Whittle jet engine was simple and started at 1200 lbs thrust. Now, the latest engines are sophisticated, electronically controlled power plants providing 80,000 lbs thrust or more for the jumbo twin jet passenger aircraft. These are very complex products using state of the art metallurgy and three spool compressor turbine by-pass systems. They are designed with quality assurance uppermost and are tested with fantastic care before being put into service.

The axial flow engine has become so reliable and able to produce so much power so cheaply from relatively small installations that it has found use in many fields other than aircraft propulsion. It is now used extensively as the power plant for ship,. for oil rigs and for domestic power supplies in remote places.

Jet engine development in the 20th century has been spectacular and it is now almost impossible to recognise the latest by-pass engines as the same animal which Whittle produced, yet the same simple principle of operation remains.

Sir Alex Morris