Boeing favours GE for latest 747-400 development

MAX KINGSLEY-JONES / SINGAPORE

Boeing plans to retain the General Electric CF6-80C2 for its latest 747-400 development after confirming its aim to launch in June. But Rolls-Royce is pushing for its new Trent 600 to be offered on the aircraft.  Dubbed the 747-400X Quiet Longer Range (QLR), the model's development schedule calls for service entry in March 2004, equipped with the 63,300lb-thrust (280kN) CF6-80C2B9F.

Talks are being held with R-R about a Trent 600-powered version, and the UK manufacturer says it could meet a mid-2004 in-service date. Boeing has been working with all three 747 engine suppliers - GE, R-R and Pratt & Whitney - but GE is leading the programme. The R-R RB211 is not powerful enough for the QLR, so R-R is proposing its 63,000lb-thrust Trent 600, derived from the Trent 500.

Boeing vice president 747 programme Jeff Peace says: "[Trent 600] timing isn't right due to engine/airframe integration issues, such as the availability of a strut."

The QLR project, which Boeing says is now at "offerable" status, comprises aerodynamic changes, increased weights, more powerful, acoustically treated engines and a new interior (Flight International, 12-18 February). Passenger and freighter versions are offered, and Boeing is believed to have presented the aircraft to Cathay Pacific and Singapore Airlines.

At take-off weights of up to 396,900kg (875,000lb), the QLR will offer slightly better (+3%) range performance than the current 747-400, and complies with stringent QC2 departure noise limits at London Heathrow. If QC2 compliance is not needed, the aircraft can operate at its new structural maximum take-off weight of 417,800kg to provide between 5% and 15% more range (see table).

Using a predetermined departure profile, Peace says the thrust rating will be used to its maximum level to achieve rapid acceleration and lift-off, then the thrust will be manually reduced to pre-determined levels to reduce noise.

"The Trent 600 would provide better performance and noise margins," says R-R executive vice president airlines Charles Cuddington.

The wing will be modified with a new raked wingtip, and a trailing-edge wedge on new outboard double-slotted flaps, which combine to improve aerodynamic efficiency and provide a 1-2% reduction in fuel consumption.

Source: Flight International