The Hindu Business Line : Rolls-Royce's Trent engines

THAT an aircraft engine is an extremely complex piece of machinery is well known. But what is not is that the final assembly of the engine is done by hand.

"Building an aircraft engine is a complex process and requires absolute attention to detail and precision. This is not something that can be done on a moving line. The final assembly is carried out by skilled fitters. Engines are hand-built by all manufacturers," said Mr Martin Johnson, Vice-President, Communication, Rolls-Royce, during this correspondent's visit to the Rolls-Royce engine shop at Derby in the UK.

But before you rush to cancel your next flight booking relax. "The fitters who do this job are among the most highly skilled in Rolls-Royce. They are only able to work at this facility after several years of training and qualification," Mr Martin said.

The focus of production in Derby is the Trent series of high-thrust engines, the first of which took to air in 1995. Different versions of the Trent engines series power some of the latest wide-body aircraft produced by both the European manufacturer, Airbus, and the American Boeing.

To understand just how complex an aircraft engine is consider this: A Trent engine has 20,000 components. Seen from a passenger's perspective, one of the most obvious features is the large set of fan blades on the front. On the Trent 900 for the new Airbus A-380 superjumbo, these are 116 inches (almost 10 feet) in diameter. They are hollow, made of titanium, and running at full speed suck in more than a tonne of air every second.

The high-pressure turbine blades, at the heart of the engine, operate in temperatures that are 400 degrees Celcius higher than the melting point of the special alloys of which they are made. They include passages through which cooler air is passed, enabling them to operate safely. Each one of these two-inch blades produces the same power as a Formula 1 racing car.

However, it is only the final assembly of an aircraft engine that is done by hand. The manufacture of engine components in many cases is a highly automated process. Rolls-Royce makes 30 per cent of its engines (by value) in-house, with the remainder bought from suppliers around the world.

"The parts that we make ourselves are those which require high levels of expertise in design and manufacturing techniques. These include the engine's high-pressure turbine blades where the manufacturing process includes robots, laser measurements and drilling minute cooling passages using electronic charges," a company official said.

Components for the engine come from several hundred suppliers around the world. "Around one third of a typical Trent engine programme is shared by Rolls-Royce with Risk and Revenue partners. These include companies such as Goodrich, Honeywell, Volvo, Mitsubishi and Kawasaki which have expertise in supplying specific technologies," company officials pointed out. Despite the huge amounts of money involved in developing an aircraft engine, Rolls-Royce will not be approaching the government for investment on its latest programmes — the Trent 1000 for the Boeing 787 and the Trent 1700 for the Airbus A-350. Officials explained that Rolls-Royce has traditionally used Risk and Revenue partners to share in the investment phase. "This is the company's preferred route," the officials said. Besides, often it had been found that it is easier to source funds at more competitive rates from the open market than seek them from the Government.

The Trent engines are assembled at 57 Test Bed, the biggest Rolls-Royce engine test facility in Derby. Opened in the mid-1990s, this facility is mostly used for development testing of new Trent engines. It can handle engines up to 140,000 lb thrust. "The most powerful Trent we currently build (the Trent 800 for the Boeing 777) has a thrust of 95,000 lb, so the test bed has plenty of capacity for engine growth; 57 Bed was designed to the latest, high environmental standards. Even with an engine running at full power in the test cell, a person walking next to the building would not hear any noise," Mr Martin said.

Once the engines are assembled, they are sent by road to the Airbus facility in Toulouse. Those bound for Seattle in the US where Boeing has its manufacturing facility are first driven to Scotland and then air freighted.

Rolls-Royce produces several 100 engines a year but the rejection rate is very low and occurs mostly due to some minor human oversight.

The variety of aircraft that the Trent powers includes the Airbus A-330, A-340, the double-decker Airbus A-380 and the yet to be manufactured Airbus A-350. Similarly, the Boeing 777 and the Boeing Dreamline B-787, which is yet to be manufactured, will be powered by these engines.

The Trent series of engines could also power airlines in India. For instance, Rolls-Royce is in the campaign with both Jet Airways and Kingfisher Airlines to power the A-330s that the two plan to acquire.

Similarly, Trent may also power the A-380 aircraft that Kingfisher Airlines plans to acquire. The order for installed and spare engines for the two airlines alone could be worth as much as 400 million pounds. Besides, Trent could also power the Boeing 787 aircraft that Air India plans to acquire.

The company has a huge presence in India as IAE, in which Rolls-Royce is a shareholder; it makes the V-2500 engines that power the aircraft operated by Indian Airlines, Kingfisher and the low-cost airline, Air Deccan. Besides, the yet-to-start low-cost airline, IndiGo, has also decided to go in for the V-2500 engines for its entire fleet of 100 Airbus A-320 aircraft.

But since engines are manufactured both by European and American companies, how does a traveller find out which engine is powering the aircraft that he is flying? It is as easy as reading the clock: Those made in the UK turn clock-wise, and the ones built in the US anti-clockwise.

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