Air Transport

UK manufacturer's vision of the future includes more electricity, fewer parts and less fuel

Rolls-Royce has revealed the first details of engine proposals for Boeing's Sonic Cruiser. They now form part of a newly unveiled "Vision" strategy covering engine development for the next 20 years.

The Sonic Cruiser proposals fall into Vision 10 - the mid-term phase of the three-phase strategy. Vision 5 covers near-term, off-the-shelf technology to upgrade existing engines, while Vision 10 and Vision 20 embrace advanced engine concepts and technology features.

R-R engineering and technology director Mike Howse says the Sonic Cruiser engine will be "the first member of a new generation to include Vision 10 technology". The engine will be based on the company's triple-shaft Trent architecture, but will have a larger core to meet the high-speed aircraft's greater cruise thrust requirements.

It will also incorporate "more- electric engine" technology, which includes an internal starter motor/ generator in place of a conventional gearbox, as well as active magnetic bearings, intelligent sensors and shaft-mounted generators. Electric starter-generator technology is being tested as part of the European Union's Affordable Near Term Low Emissions (ANTLE) engine research programme. Tests begin next year, with a range of new technology, validated on the Trent 500-based demonstrator, expected to be available for commercial use by 2008.

"It will also probably have a single-stage fan, but that's not definite," says Howse, adding that the design will also have a 20% lower parts count. Weight will also be cut by the use of blisks and blings (bladed, fibre-reinforced rings).

Near-term Vision 5 advances come from off-the-shelf technology in areas such as combustor design and low-pressure turbine aerodynamic improvements, and will be available for upgrades of existing engines, says Howse. Longer-term Vision 10 technology is aimed at specific performance targets that R-R wants to reach by 2010. Compared to current engines, these include a fuel consumption reduction of 10%, a 50% cut in oxides of nitrogen  emissions and a 10dB noise reduction.

Vision 20 studies could include advanced cycles, tip-driven fans, contra-rotating aft fan concepts and new technologies such as small, efficient cores and alternative fuels.