General Electric has redesigned the engines that will power the Boeing 777X to have thinner and stronger blades than any GE engine in service, and to power the aircraft more efficiently with fewer of them.

GE has designed advanced carbon-fibre composite fan blades for its GE9x engine. The 777X, scheduled to begin production in 2017, will sport two of them. The type as of July had secured 300 orders and commitments from six customers. Since powering the 777X in 2013, nearly 700 GE9X engines have been ordered, GE says.

The engine component redesign comprises carbon fibre and improved epoxy resin fan blades, the company announces. The blades’ leading-edge material also will be made from a steel alloy rather than titanium to increase strength.

"It has been a decade since GE designed a new composite fan blade for the GEnx engine,” Bill Millhaem, general manager of the GE90/GE9X engine programs, said in a prepared statement. “Carbon fiber composite material has advanced in those 10 years, and the advancements enable GE engineers to design a thinner GE9X blade, which is just as strong as our current composite fan blades. Fewer, thinner blades will enhance the airflow and make for a lighter, more efficient fan that will help with the GE9X engine’s overall performance and fuel burn.”

Company engineers last year successfully tested full-size modified blades on its GEnx engine, which along with the GE90-94B and GE90-11B are precursors to the GE9X blades. The new materials will be tested on the GE9X blades in 2015, GE says. IHI Corp., Snecma and Techspace Aero and MTU Aero Engines have also joined the effort to develop the GE9X.

Plans are to spend $300 million in 2014 on development of the 100,000 thrust-class GE9X, including universal propulsion simulator (UPS) fan testing. The engine’s new ceramic composite combustor and turbine – designed to withstand extreme heat of heavily pressurised air within the engine’s core – also will undergo testing this year.

The GE9X also will feature a 133-inch diameter composite fan case housing 16 blades, a 27:1 pressure ratio, 11-stage compressor and a third-generation twin annular pre-swirl combustor (TAPS) for greater efficiency and low emissions, GE says.

The first full core test is scheduled for 2015, the company says. The first engine will test in 2016 with flight testing on GE’s flying test bed anticipated in 2017. Engine certification is scheduled for 2018.