Rolls-Royce has revised its earlier proposed Trent 680 engine offering for future growth developments of the Boeing 747-400X in favour of a smaller sized powerplant development based on the new Trent 500 rather than the larger Trent 900 under development for the Airbus A380.

Boeing is looking for alternative new powerplants or improvements to existing engines for a series of planned increased growth versions of the 747-400 now under study for 2004. The principle driver is the need to meet the more stringent Quota Count 2 noise limit on aircraft departing from London's Heathrow airport due to come into force next year and which will likely set the standard for other airports internationally.

R-R is now focusing attention on offering a Trent 600 rated at around 63,000lb thrust (280kN), which would be based on a uprated development of the Trent 500. The engine would share the same 2.8m (97.5in) fan diameter as the Trent 500 which has been initially developed as 53-56,000lb-thrust application for the Airbus A340-500/600, but which is already certified to 60,000lb-thrust.

The Trent 600 was originally conceived as a 68,000-72,000lb- thrust family of engines to power the stretch and longer-range 747X and 767-400X derivatives, development of which Boeing shelved earlier this year in favour of the sonic cruiser. The Seattle-based manufacturer has since began to look at less ambitious improvements to try and sustain the 747-400 by increasing the maximum takeoff weight up to 431,000kg (950,000lb).

As the Trent 680, the engine would have incorporated a 2.6 diameter fan and used technology being developed for the 80,000lb thrust Trent 900 to power the A380, including swept blades and a contra-rotating high pressure compressor.

Source: Flight International