Here’s How Much Larger The GE9X Is Compared To The GE90

The General Electric GE90 was once the undisputed king of commercial aircraft engines, and when it entered service in the 1990s, it pushed boundaries in a way few aviation technologies ever had. Its massive size, record-breaking thrust, and innovative composite fan blades made it a defining feature of long-haul aircraft like the Boeing 777. For years, it stood as both the largest and most powerful turbofan engine ever to enter service.

Then came the General Electric GE9X, designed for the upcoming Boeing 777X. At first glance, it looks like a natural evolution of the GE90, but a closer inspection reveals something more significant. The GE9X is not just incrementally larger, it represents a deliberate shift in how size, efficiency, and performance are balanced. While the raw numbers tell part of the story, the real difference lies in what that added size allows engineers to achieve. Let’s take a closer look…

The Six-Inch Difference That Changes Everything

The most commonly cited comparison between the General Electric GE90 and the GE9X is their fan diameter – the former measures 128 inches across (325 centimeters), while the GE9X stretches to 134 inches (340 centimeters). On paper, six inches (15 centimeters) might not sound like a major leap, but in practice, it is enormous. The fan is the largest single component of a turbofan engine, and even a small increase in diameter translates into a much larger intake area. Because the area of a circle increases exponentially with diameter, those extra inches allow the GE9X to ingest and accelerate significantly more air.

This is the key to understanding why the General Electric GE9X is bigger. Modern turbofans generate most of their thrust by accelerating a large volume of air at a relatively low speed, rather than blasting a small amount of air very fast. By increasing fan diameter, engineers can push more air around the engine core, improving propulsive efficiency and reducing fuel burn, and the GE9X’s 134-inch fan enables a bypass ratio of about 10:1, higher than the GE90’s 9:1 bypass ratio, which directly contributes to better efficiency.

The visual impact of this increase cannot be overstated either, with the General Electric GE9X’s fan case measuring roughly 11 feet (3.35 meters) across, making it wider than the fuselage of some narrowbody aircraft. For aviation enthusiasts alike, the difference is immediately noticeable, and standing next to it, the GE9X does not just look like a slightly larger engine, it looks like a different class of machine altogether.

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A Noticeable Jump In Scale

While its fan diameter gets the most attention, the General Electric GE9X is also larger in overall proportions. Its nacelle and outer casing are designed to accommodate the increased airflow and improved aerodynamics required by the bigger fan. The engine’s width grows more than its length, giving it a bulkier and more modern appearance when mounted under the wing.

The General Electric GE90, often used on the Boeing 777-300ER, was already massive by any standard, but the GE9X takes that presence even further. It weighs over 21,000 lbs (9,525 kg) and has a wider overall profile, reflecting the structural changes needed to support the larger fan and higher airflow. At the same time, engineers avoided simply scaling up every dimension, and the length of the GE9X, for example, remains relatively controlled compared to its diameter, showing that the design emphasis was placed on airflow efficiency rather than sheer size.

Another important aspect of this size increase is how it integrates with the aircraft. The Boeing 777X features a redesigned wing and higher ground clearance, allowing it to accommodate the larger engine without compromising safety or aerodynamics. The aircraft also features innovative folding wingtips, which although not directly related to its engines, form part of its overall operational performance.

Fewer Blades, Bigger Impact

One of the most surprising ways the General Electric GE9X differs from the GE90 is in the number of fan blades – the GE90 uses 22 composite fan blades, while the GE9X reduces that number to just 16. At first, this seems counterintuitive, as a larger fan might be expected to require more blades, not fewer. But advances in aerodynamics and materials have made each blade more capable, and the GE9X’s fourth-generation composite blades are larger, stronger, and more efficient, allowing them to move more air with fewer components.

This change contributes directly to the engine’s size difference, with each blade on the GE9X being longer and more sculpted than those on the GE90, helping to maximize airflow while reducing drag. Fewer blades also mean less weight and less aerodynamic resistance, both of which improve efficiency, and the result is that the GE9X does not just look bigger, it behaves differently, and its fan system is optimized to take full advantage of its increased diameter, rather than simply filling space with more components.

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A Larger Fan Means A Higher Bypass Ratio

The increase in fan size directly leads to one of the most important performance differences between the two engines – bypass ratio. The General Electric GE90 already had a high bypass ratio, but the GE9X pushes this further, reaching around 10:1 compared to roughly 9:1 on the GE90. Bypass ratio refers to how much air flows around the engine core compared to how much passes through it. A higher ratio generally means better fuel efficiency and lower noise; the larger fan of the GE9X makes this possible by allowing more air to bypass the core.

This is where the added size becomes truly meaningful. The GE9X is not bigger just for visual impact, it is bigger because that size enables a fundamentally more efficient way of generating thrust. By moving more air at lower speeds, the engine reduces fuel consumption and emissions while also operating more quietly. In practical terms, this corresponds to approximately a 10% improvement in fuel efficiency relative to the GE90, which is a substantial gain in an industry where even small percentage improvements can have major economic and environmental implications.

The GE9X Has Less Thrust Despite Its Size

Boeing 777-9 taxiing with wingtips folded

One of the most interesting aspects of the General Electric GE9X is that, despite being larger, it produces less maximum certified thrust than the GE90. The GE90 can deliver around 115,000 pounds of thrust in service, while the GE9X is typically rated at about 105,000 pounds.

This might seem contradictory, as a larger engine would intuitively produce more power, but the General Electric GE9X reflects a different design philosophy. Instead of maximizing thrust at all costs, engineers focused on optimizing efficiency for the Boeing 777X.

The reason lies in how modern aircraft are designed, and the Boeing 777X features more advanced aerodynamics and lighter materials, much like the Boeing 787 before it, meaning it does not require the same extreme thrust levels as earlier models. The General Electric GE9X’s larger fan allows it to generate the necessary thrust more efficiently, even if the peak number is lower.

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The Role Of Advanced Materials

Making an engine larger is not simply a matter of increasing dimensions, because as size increases, so do the stresses on components, especially at the high rotational speeds required for a turbofan. This is where the General Electric GE9X distinguishes itself from the GE90 through its use of advanced materials.

The General Electric GE90 was already groundbreaking in its use of carbon-fiber composite materials for the fan blades, which were lighter and stronger than traditional metal designs. The GE9X builds on this foundation with newer composites and ceramic matrix composites in the engine core. These materials are critical to enabling the General Electric GE9X’s larger size, as they allow the engine to operate at higher temperatures and pressures without adding excessive weight. In fact, some components are lighter despite being larger, which helps offset the overall increase in engine dimensions.

The combination of a bigger fan, fewer blades, and advanced materials creates a design that would not have been possible during the General Electric GE90’s development era. The GE9X is larger because technology now allows it to be larger without sacrificing efficiency or reliability.

Seeing The Difference In Real Life

Photographs comparing the General Electric GE90 and GE9X often provide the most striking illustration of their size difference, and what stands out in these comparisons is not just that the GE9X is bigger, but how that extra size is distributed. The engine appears more refined and aerodynamically smooth, with a wider intake and a slightly different overall shape, and it looks less like a simple enlargement and more like a new generation of design.

For anyone standing near one on the ground, the difference is unmistakable – the General Electric GE90 already feels enormous, but the GE9X takes that sense of scale and pushes it just a bit further, enough to redefine expectations of what a jet engine can look like.

We will have to wait until at least 2027 to see the General Electric GE9X in action, when the Boeing 777X enters commercial service. Emirates is currently set to become the world’s largest operator of the aircraft, with the carrier, based at Dubai International Airport (DXB), having a staggering 270 on order – 35 of the smaller Boeing 777-8 and 235 of the larger Boeing 777-9.