A 10 percent increase in fuel efficiency might not sound like a lot, but in aviation, according to Wired, “engineers would step over their own mothers for a one percent bump.”
As large in diameter as the body of an entire Boeing 737, the GE9X is the biggest jet engine in the world, and it delivers those extra fuel savings and more. GE Aviation has built the engine for the new Boeing 777X planes and started testing it in March. It’s also one of GE’s biggest draws at the Farnborough International Airshow, which started near London, England, on Monday.
The GE9X isn’t the most powerful engine GE makes — that world record belongs to the GE90-115B — but in addition to its size and fuel efficiency, the GE9X also makes less noise and runs cleaner than any other GE engine to date, which will help airlines meet increasingly strict environmental rules.
The massive machine gets its moxie from design and engineering breakthroughs such as 3D-printed nozzles that efficiently spray fuel inside the combustor. GE’s industrial 3D printers make them directly from a digital file by fusing ultra-thin layers of metal powder with a laser one after another to create shapes that otherwise would have been hard or impossible to achieve. “3D printing has changed the way engineers create and have made what was impossible possible,” says Greg Morris, who runs additive programs at GE Aviation.
Another key part is the so-called engine shroud, which captures and channels the incandescent air inside the turbine. The GE9X version is made from light and heat-resistant space-age ceramics called ceramic matrix composites (CMCs). “CMCs allow for a revolutionary change in jet engine design,” says Jonathan Blank, who leads CMC and advanced polymer matrix composite research at GE Aviation.
The shroud can work at temperatures as high as 2,400 degrees Fahrenheit, where even advanced alloys grow soft, and have twice the strength and a third of the weight of metal components. This is hugely important because they allow engineers to extract more work from the heat inside and also make for lighter engines — a big deal given that the plane has to constantly carry them around the world. The GE9X uses CMCs to also in the combustor liners and high-pressure turbine nozzles.
Another crucial component is the engine’s 11-foot fan. It uses blades made from light and tough fourth-generation carbon-fiber composite finished off with a stainless steel leading edge. No other engine maker has composite blades in service, but the GE9X fan is revolutionary even for GE. That’s because it includes just 16 blades, down from 22 on the GE90 and 18 on the GEnx, which powers the Dreamliner. Again, fewer blades cut the engine’s weight and add more power.
GE Aviation is now testing the first complete GE9X at its boot camp for jet engines in Peebles, Ohio. The company also invested $100 million in a new facility for testing lean-burn combustors at its headquarters in Evendale, Ohio, near Cincinnati.
GE says the engine is ahead of normal development schedules. Says Ted Ingling, general manager of the GE9X program at GE Aviation: “For the GE9X, we have been maturing the technologies for the last five years and ran the first engine to test (FETT) much earlier than in other programs — just six months after finalizing the design.”