Rolls-Royce is considering refocusing its development efforts on a new 245-290kN (55,000-65,000lb)-thrust member of its Trent turbofan family, following Boeing's recent decision to cancel the 747-X project, say senior executives at the UK company.

R-R's managing director Aerospace Group, Colin Green, confirms that the new derivative, which is still at the conceptual phase, and "one of a number of advanced projects", would use a scaled-down Trent 800 core and the fan of the Trent 700.

The study is set to gather momentum, however, following Boeing's announcement that it is stepping up work on the 767-400ERX stretch, coupled with Airbus Industrie's moves towards launching its A340-500/600 derivatives this year.

R-R had been expecting to complete development of its latest engine, the 355kN Trent 900, in time for a December 2000 service-entry on board the 747-X. This derivative, which also uses a scaled-down Trent 800 core but retains the full-size fan, is not now likely to be required until at least late-2003, for the Airbus A3XX.

Sir Ralph Robins, R-R chairman, hinted at the latest study during a 4 February speech at the UK Royal Aeronautical Society in London, saying: "A smaller core [than that of the Trent 900], also scaled from the Trent 800 but using the Trent 700 fan, would produce a very exciting 55,000-65,000lb [245-290kN] engine." He added that the same core could be integrated into the RB.211-535, which powers the 757, "-should there be a requirement".

Meanwhile, General Electricis still talking to Airbus, on an exclusive basis, about its 245-267kN GEXX proposal for the stretched A340, while Boeing envisages using engines in the 276kN class on the 767-400ERX.

R-R says that the "hybrid" version of the RB.211-524 which it is now developing will improve specific fuel consumption by 2%, weigh 90kg less and reduce exhaust-gas temperature by 25¹C, compared with -524G/H models.

The hybrid, which integrates the Trent 700 core with an otherwise unchanged -524, will also offer improved durability, says the company. Test-cell certification is planned for April, followed by flight testing which will begin late this year, using a Boeing 747.

Source: Flight International