Rolls-Royce is investing in the development of a significantly modified version of the Trent XWB for the A350-1000 to help Airbus enhance the performance of its largest twinjet.
R-R, the sole engine supplier on the A350 programme, is expected to confirm that it is broadening the changes it plans for the most powerful Trent XWB variant at next week's Paris air show. This is when Airbus will unveil details of a revamped A350-1000 with increased weights and longer range.
Neither Airbus or R-R are talking about the developments ahead of the show, but sources familiar with the situation indicate that a 5,000lb thrust (22kN) increase to the 350-seat A350-1000's 93,000lb Trent XWB - made possible by changes to the core - will allow Airbus to increase the design weights and extend the range by 500nm (925km), and enlarge the wing.
"Rolls has accepted that it must increase the engine thrust," said Akbar Al Baker, chief executive of A350-1000 launch customer Qatar Airways. "We'd like increased take-off weight and increased range."
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The UK engine maker is testing the baseline 84,000lb thrust Trent XWB which will power the A350-800/900 and has run that engine to 100,000lb thrust. It has been evaluating the changes required to allow the engine to operate comfortably at a 93,000lb rating for the A350-1000, with plans centred on revisions to materials and fan.
But as Airbus has worked to complete the detail definition of the -1000, some customers have sought an increase to the payload-range capability, meaning that a higher baseline thrust rating is required to allow increased operating weights. A350 customers such as Emirates chief Tim Clark have been pushing Airbus to increase the largest XWB variant's competitiveness with the rival Boeing 777-300ER.
Flight International understands that, to achieve this and possibly provide room for further growth, R-R has decided to redesign the core for the A350-1000's Trent, enabling a flat rating of 98,000lb thrust. Details about the changes are scant, although industry sources speculate that such thrust growth could most likely be achieved through a redesign of the intermediate- or high-pressure turbine with the addition of another stage.
Industry sources say such a redesign would require the investment of around $250 million and eliminate some commonality with the lower-thrust Trent XWBs, thereby complicating spares provisioning.
However, the engine revamp would create a far more capable A350-1000 and improve its marketability when up against the 777-300ER, and possibly discourage Airbus from seeking a second engine supplier, General Electric, for the programme.
It also makes Boeing's job harder as it evaluates how it should revamp the 777 to remain competitive. Although Boeing has an exclusive engine supply deal with GE on the current 777 variants, the development of an improved Trent XWB could make it a strong powerplant candidate for any 777 upgrade or successor.
Source: Flight International
