General Electric will find out later this summer how the core of the new engine for the 777X performs in an isolated ground test.

The maturation testing on the high pressure compressor rig will provide GE with the first performance data on a key element of the engine's performance up to five years before scheduled certification of the GE9X.

"When you think about it, we were selected in March by Boeing and in July we'll be running our first compressor," says Bill Millhaem, general manager of the GE9X programme.

The compressor is one of the keys GE is relying upon for the new engine to deliver a 10% improvement in fuel efficiency. The compressor squeezes the air before it is fed into the combustion chamber to be ignited and vented through the turbine.

Compared to the GE90 on the current 777 family, GE has designed the GE9X with an additional stage in the compressor and a fourth generation powered metal alloy that can survive in higher temperatures. Both changes increase the pressure ratio inside the compressor by 20% to 27:1, which alone accounts for one-fifth of the predicted fuel burn reduction compared to the GE90.

The tests will be conducted at GE's oil and gas power turbine testing facility in Massa, Italy. The compressor rig testing is part of GE's $200 million investment this year to keep GE9X development on schedule.

Overall, GE is investing more than $2 billion to bring the GE9X to market with the 777X family by the end of the decade. The compressor rig tests will be followed by testing on the carbonfibre composite fan blades and 335cm (132in)-diameter composite fan case for the GE9X. Next year, GE also will begin tests on the ceramic matrix composites in the hot section of the GE9X.

"Our compressor begins test five years before certification and we are 3.5 years into the design of [the GE9X]," says Bill Fitzgerald, vice-president and general manager of GE commercial engines. "I would say that we've got a much more proactive look at demonstrating that these technologies are ready."

Source: Air Transport Intelligence news