1. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3

2. Armourers and Brasiers Company Materials around us Prepared by Dr Diane Aston, IOM3

3. Armourers and Brasiers Company The aim of this module is to introduce you to three areas in which discoveries and developments in materials have helped to improve our technology in three key areas: Turbofan engines for civil aircraft Biomedical materials Sports equipment Prepared by Dr Diane Aston, IOM3

4. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3

5. Armourers and Brasiers Company The session aims to introduce you to the technology and materials behind modern high by-pass turbofan jet engines. At the end of this session you should be able to: Explain in simple terms how a turbofan jet engine works; Describe the key characteristics of materials used in the fan, compressor and turbine stages of a turbofan engine; Describe the materials and processing used in wide chord fan blades; Describe how changing microstructure has helped to improved the performance of turbine blades; Describe in simple terms how turbine blades are manufactured. Prepared by Dr Diane Aston, IOM3

6. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3

7. Armourers and Brasiers Company On a modern engine the fan can be up to 3m in diameter. Between 80 and 90% of the air entering the engine is directed through the bypass. This fast moving air produces most of the thrust. A large engine can take in the same amount of air as there is in a squash court every second. Having a high bypass ratio reduces noise and increases fuel efficiency. A RR Trent 800 jet engine generates 100,000lbs of thrust. A typical large turbofan costs in excess of £10 million! Prepared by Dr Diane Aston, IOM3

8. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 Blade design was limiting factor in jet engine size. Blades used to be solid forgings that were very heavy. Blades need to be lightweight, strong and stiff. Titanium blades made by super- plastic forming and diffusion bonding. Blades have a hollow, corrugated cross section. This photograph is reproduced with the permission of Rolls-Royce plc, copyright © Rolls-Royce plc 2010

9. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 The compressor is made up of a series of rotating blades separated by stationary vanes. These compress the air so that when it exits the high pressure compressor it is at around 600  C. Compressor blades made from titanium as it is strong, light and able to operate at 600  C. Blades are made by hot forging and then machining. Blades sit on a series of rings.

10. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 Forced rotation of turbine drives rest of engine. Operate under extremes of temperature and pressure. Made from nickel-based superalloy. Blades attach to disc with fir tree root. Blades have in-built cooling system to prevent them overheating and melting during operation.

11. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 Materials Superalloys retain their properties up to over half of their melting point Nickel-based superalloys are mainly Ni with small amounts of Ti, Cr, Mo, Mn, Al, Fe and B added; third and forth generation alloys also contain Ru and Re too. Each element is added to control the microstructure and properties. Manufacturing First a core is made from ceramic in the shape of the internal channels. A wax pattern in the shape of the blade is built around the core A shell mould is made around the wax patterns. The blade is cast and cooled under critical conditions The core is dissolved out Final machining of root and cooling holes.

12. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 The engines have to be thoroughly tested to ensure that they can cope with all possible operating conditions. There are two key tests: Blade-off test Bird strike test

13. Armourers and Brasiers Company Jet engines are incredible pieces of technology operating under extremes of temperature and pressure. Advances in materials and manufacturing technology have allowed engineers to create quieter and more efficient engines. Prepared by Dr Diane Aston, IOM3

14. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 Calculating fuel efficiency Journey through a jet engine?

15. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3

16. Armourers and Brasiers Company Prepared by Dr Diane Aston, IOM3 Calculating fuel efficiency

17. Armourers and Brasiers Company This is a quick and easy calculation to put into perspective how much fuel a jet engine uses. Calculate the fuel efficiency of two different aircraft and compare this to the fuel efficiency of two different cars. Compare the relative fuel efficiency per person for each vehicle. Discuss which mode of transport is most fuel efficient. Prepared by Dr Diane Aston, IOM3

18. Armourers and Brasiers Company The Rolls Royce website has an excellent resources that encourages the user to go through the stages in a jet engine and then test their understanding.Rolls Royce website Can you get all 16 questions right? Prepared by Dr Diane Aston, IOM3

19. Armourers and Brasiers Company The Wikipedia article on turbofans explains how they work in a relatively easy to understand yet detailed way.Wikipedia article The Rolls Royce website has some excellent written information, diagrams and video clips on all aspects of jet engine design. It is worth having a look at the materials and gas turbine sections on the technology page.Rolls Royce website The same site also has downloadable PDF factsheets on all of the large Rolls- Royce engines.site Rolls Royce produced a book called The Jet Engine. It is a fabulous read with some beautiful photographs. It is quite expensive at £35 and is available from herehere The BBC did a documentary a couple of years ago called How to build a jumbo jet engine. Someone has uploaded it to YouTube and it has great sections on each area of the engine.YouTube Prepared by Dr Diane Aston, IOM3