Three engine makers will make contrasting pitches for Boeing's proposed new twinjet, but all are likely to be bleedless

The battle to power Boeing's proposed 7E7 is heating up with the three major engine manufacturers taking different approaches to developing a 63,000-68,000lb-thrust (280-302kN) powerplant for the ultra-efficient airliner. Boeing plans to pick a maximum of two engines and possibly only one.

Rolls-Royce is looking at a potential development launch of its proposed Trent 7E7 engine in the second quarter of 2005. This would have a bypass ratio of around 10:1 and is understood to draw on existing powerplant technology, combining a 2.84m (112in) Trent 900 fan with a Trent 500 core.

P&W in contrast is looking at the proposed PWEXX as the foundation for a potentially new engine family to succeed the PW4000 series. It is looking at a fan similar in size to the Trent 7E7 and a bypass ratio in the range of 11:1. Other potential features would include the use of Talon X combustor technology for lower emissions, sixth generation full authority digital engine control and advanced health monitoring.

General Electric is the least forthcoming on its 7E7 bid, which is linked to its desire for exclusivity on the programme. It is looking at a new engine built on a scaled GE90 hot section incorporating elements of its GEN X and Tech56 technology projects. Various fan designs are being considered, ranging in size from 2.84m to 2.92m, with target bypass ratios of between 11:1 and 12:1 and an overall pressure ratio of around 50:1.

All three proposed 7E7 engines are likely to be bleedless designs as Boeing shifts towards a more electric aircraft. This will make it difficult for Airbus to adopt any of the engines to improve the competitiveness of the heavier A330.

Source: Flight International