Impressive Progress of GE90-115B Engine Continues
FARNBOROUGH - Marked success continues to characterize product definition and development testing of the GE90-115B, the world's most powerful turbofan engine and the exclusive powerplant for Boeing's longer-range 777-200 and -300 twinjets.The 777-200 and -300 aircraft were launched in a joint Boeing/GE press conference on February 29, and the next month, Japan Airlines became the first carrier to announce its selection of GE90-115B-powered longer-range 777-300s for its fleet, with delivery to begin in 2004.The GE90-115B is distinguished by swept fan blades, a high-efficiency high pressure compressor (HPC), and greater torque capability in the fan mid-shaft.The GE90-115B's high-flow swept fan blades are manufactured from the same materials (fibers and resin system), and by the same process, as current GE90 radial fan blades, which have accumulated more than 1.25 million flight hours during four and one-half years of service. As robust as its predecessor, the swept fan blade adds approximately 2,000 pounds (8.9 kN) to the engine's thrust and contributes to low fuel burn signature. In addition, airflow is increased by growing the fan diameter from 123 inches to 128 inches. Testing of the swept fan blade at Boeing's Low Speed Aeroacoustic facility began in mid-June and continues through early August. Test objectives include measurement of performance level, acoustic level and aeromechanical stress, definition of the operating and stall line, and evaluation of operability. Three-dimensional aerodynamic (3-D aero) design of the HPC blades and vanes, implemented first on CFM56-5B and CFM56-7 engines, is now being incorporated on the GE90-94B engine to increase exhaust gas temperature (EGT) margin and reduce fuel burn. 3-D aero design of the HPC blades and vanes has been carried forward in the GE90-115B to achieve the level of efficiency required to produce 115,000 pounds (511 kN) of thrust. In addition, the number of stages in the HPC has been reduced from 10 to nine, in order to open up the compressor annulus and thereby permit greater airflow in order to manage the cycle temperatures. HPC testing, which concluded in mid-June, produced impressive results: efficiency and flow capability have met the required levels; the variable stator vane schedule has been optimized; and excellent operability and stall margin have been demonstrated.GE1014, the new high-strength steel alloy for the fan mid-shaft, significantly increases torque capability. As a result, the diameter of the mid-shaft remains the same, precluding modification of other core components. GE1014 chemistry was identified in 1996, and full-scale melt practice was defined in mid-1998. Materials property testing was completed in late 1999, at approximately the same time the first full-scale forgings were delivered. Prototype shafts have been produced and finish-machined to confirm manufacturability.FAR33 type certification of the GE90-115B by the U.S. Federal Aviation Administration and the European Community's Joint Airworthiness Authorities is targeted for 2002, with the GE90-115B-powered 777 to be ready for entry into service in 2003.