Ian Sheppard/LONDON
Rolls-Royce (R-R) is studying the development of a major RB.211-535 derivative which it believes could offer an 8% reduction in specific fuel consumption (SFC) by incorporating the core being developed for the new Trent 500.
The -535 is available on the Boeing 757 and Tupolev Tu-204. The new version would be available on these airframes and also for future twin engined aircraft.
The engine manufacturer is believed to have informed existing -535 powered 757 operators that it could introduce the core of its Trent 500 into the existing engine in the same way that the Trent 700 core has been used and certificated for the RB.211-524G/H-T to power the Boeing 747-400. The 236-276kN (53,000-62,000lb)-thrust Trent 500 is being developed for the Airbus A340-500/600 and is due to enter service in early 2002. R-R says that it is unlikely to offer a recored -535 earlier than this.
A source at British Airways, which has a large fleet of 757s, says: "There is much interest from our side," although it is sceptical that an 8% SFC reduction is possible.
R-R is yet to decide whether to develop a new fan system. R-R's director of engineering at the Derby, UK-based commercial engines division, Mike Howse, speaking at a Royal Aeronautical Society lecture at Cranfield University following the launch of the R-R-backed university technology centre in early March, said the core could be used "-with or without a new fan system".
Howse also re-affirmed the company's commitment to the three spool concept upon which all of its large engines now revolve. He thinks, however, that the concept is not applicable "below about 30,000lb thrust".
Howse also rejected the idea that ultra high bypass engines are the way forward. He outlined "further developments" which were still possible, including an overall pressure ratio of 60 (compared with 40 now) and a 360íC higher turbine-entry temperature - with a bypass ratio of 10:1 - and "innovative" containment and mounting systems to give airlines "a 15% benefit in operating cost".
Howse added that the company was aware of the need to introduce new technology slowly.
"The skill will be applying it when and where the customer requires," he said.
Source: Flight International
