General Electric GEnx - Design and Development

Design and Development

The GEnx and the Rolls-Royce Trent 1000 were selected by Boeing following a run-off between the three big engine manufacturers. The GEnx uses some technology from the GE90 turbofan, including composite fan blades, and the smaller core featured in earlier variants of the engine. The engine carries composite technology into the fan case.

Both engine types will have a standard interface with the aircraft, allowing any 787 to be fitted with either GE or RR engines at any time. The engine market for the 787 is estimated at US$40 billion over the next 25 years. A first is the elimination of bleed air systems using high temperature/high pressure air from the propulsion engines to power aircraft systems such as the starting, air-conditioning and anti-ice systems. The GEnx and the Trent 1000 allow a move towards the More Electric Airplane.

The GEnx is expected to produce thrust from 53,000 to 75,000 lbf (240 to 330 kN) with first tests commencing in 2006 and service entry by 2008 (now delayed by 787 deliveries). Boeing predicts reduced fuel consumption of up to 20% and significantly quieter engines than current turbofans. A 66,500 lbf (296 kN) thrust version (GEnx-2B67) will be used on the 747-8. Unlike the initial version, for the 787, this version has a traditional bleed air system to power internal pneumatic and ventilation systems. It will also have a smaller overall diameter than the initial model to accommodate installation on the 747.

General Electric began initial test runs of the bleedless GEnx variant on 19 March 2006. The first flight with one of these engines took place on 22 February 2007, using a Boeing 747-100, fitted with one GEnx engine in the number 2 (inboard left hand side) position.