Farnborough Air Show

Engine Options Reduce 787 Operating Cost and Noise

 - July 11, 2012, 1:55 AM

Boeing’s 787-8 is offered with both the 74,000-pound-thrust Rolls-Royce Trent 1000 engines and General Electric’s GEnx turbofans. The GEnx family has a thrust range of from 53,000 to 75,000 pounds.

The Trent 1000, which is the launch engine for the 787 family, powered the first commercial Dreamliner, which was delivered in December to launch customer All-Nippon Airlines. ANA achieved a 90-percent dispatch rate in the first three months of scheduled operations. According to Rolls-Royce, around three quarters of 787 orders to date have been for aircraft powered by the Trent 1000.

The GE engines received final U.S. certification in March. The first GEnx-1B powered Dreamliner went to Japan Air Lines on March 26 for JAL’s Boston to Tokyo route, which were the first 787 operations in the U.S., beginning in the second quarter of 2012.

GE claims a 15-percent improvement in specific fuel consumption for the GEnx family compared to comparably sized turbofans, and calls it the “cleanest, quietest, most passenger-friendly commercial engine ever produced.” The GEnx is the quietest based on the ratio of perceived decibels to pounds of thrust of engines for medium size, long-range airliners, and is said to have emissions “95 percent below current regulatory standards” with a 30-percent longer on-wing duration, in large part due to having 30 percent fewer parts than engines it replaces.

Part of the reason for the Dreamliner having markedly quieter cabin interiors than comparable widebodies is the use of a new scalloped engine exhaust nozzle fairing configuration. Advanced engine acoustic linings and new fans with larger, slower turning blades also contribute to the 787 registering an 85dB noise level in the airport environment, which Boeing claims represents a 60-percent smaller noise footprint than those of comparable airliners.