Rolls-Royce UltraFan Explained: The Engine Built For The Next Generation Of Widebodies

Aaron is an aviation enthusiast and world traveler with a deep interest in aerospace history and technology. He has traveled around the world numerous times, often incorporating visits to aviation museums and historic aircraft collections into his journeys. A native of New Zealand, he is an expert in aviation and maintains a broad interest in a variety of other subjects.

The Rolls-Royce UltraFan demonstrator is the flagship of Rolls-Royce's next generation of widebody aircraft engines. Currently, it remains unclear which aircraft the engine will eventually power: it may be a future A350 variant or updated 'neo' variants of today's widebody.

Perhaps more likely, it will eventually power cleansheet widebody aircraft that haven't yet been announced. This makes the engine a long-term project and one that won't be flying passengers for some time. Importantly, UltraFan now has a narrowbody sister demonstrator engine in development called the UltraFan 30.

While the UltraFan 80 is the largest demonstrator aeroengine ever built by diameter, the UltraFan 30 is arguably more consequential. Airbus and Boeing are studying/developing concepts for the next generation of clean-sheet aircraft that the UltraFan 30 could power. Let's take a closer look at Rolls-Royce's giant UltraFan and its two variants.

A New Family Of RR Engines

Rolls-Royce is looking beyond its current generation of engines to the next generation that will power aircraft from the mid-2030s and into the 2040s. Even as Rolls-Royce works to address the issues with its Trent 1000 powering Boeing 787s with the upgraded Trent 1000X, it is working on a new widebody turbofan.

Not only does Rolls-Royce want to keep its place in the widebody engine market, but it also wants to re-enter the narrowbody engine market. Airbus and, more recently, Boeing have announced they are working on developing the next generation of narrowbody passenger jets to replace their extremely popular A320 and 737 families.

This is providing Rolls-Royce the chance to re-enter the market. While the UltraFan demonstrator started out as the world's biggest turbofan ever built, it has now split into two branches. The UltraFan 80 is intended for the future widebody market, while the UltraFan 30 is being developed for future narrowbody airplanes.

One of the key characteristics of UltraFan is that it is intended to be scalable so that Rolls-Royce can produce a range of engine variants to power both narrowbody and widebody airplanes. It says that the engine is "designed from the outset to deliver the scale and step-change in performance airlines need to power future narrowbody and widebody fleets."

Rolls-Royce UltraFan 80

Rolls-Royce currently describes the large UltraFan 80 as having the target to deliver 25% better fuel efficiency compared with the first-generation Trent engine (original Trent 800-era) and around 10% lower fuel burn than the current Trent XWB. This engine powers the Airbus A350 family.

The UltraFan 80 will produce around 80,000 lbf and have a very high bypass ratio. The demonstrator has a diameter of 140 inches (3.56 meters). This is larger than the GE9X engine powering the Boeing 777X, which is set to be the largest in-service engine.

Rolls-Royce says the new UltraFan architecture further enhances the Advance 3 engine core and "achieves even greater propulsive efficiency by delivering a higher bypass ratio." It explains that the primary enabling technology is the power gearbox, which allows a larger diameter, lower-speed fan that is effectively decoupled from the LP turbine.

Conventional Rolls-Royce Trent engines employ a three-shaft architecture where the fan is mechanically connected through the low-pressure system. One of the key innovations of UltraFan is using a geared architecture. This is a high-speed turbine that operates at its optimum rotational speed, while the large fan turns more slowly. This produces a higher bypass ratio and increases efficiency.

Second UltraFan 80 Demonstrator Set To Run

Rolls-Royce describes the UltraFan 80 as the blueprint for the next generation of widebody engines. Having been stung by the durability issues of its Trent 1000 engines, RR said that "we’ve prioritised durability and robustness." The first test was carried out in 2023, and a second demonstrator is planned to be built.

During test runs, the engine has conducted product-representative testing at full power and 85,000 lbf. Following the test runs, the demonstrator underwent a forensic strip and inspection. Now the second UltraFan 80 demonstrator has been built and is expected to continue testing later in 2026.

As of the time of writing (October 2026), there has not been a statement that it has yet been run. One of the improvements to the engine is the composite fan. According to Rolls-Royce, the engine is expected to enter service in the 2030s with "timing determined by airframe requirements and market demand."

Rolls-Royce adds that "our UltraFan demonstrators feature carbon composite titanium fan blades with a titanium leading edge and a composite casing." This helps to reduce the weight of the overall engine, and reduced weight translates into fuel savings. The new engine goes beyond fuel savings and offers a 40% improvement in NOx emissions and 35% lower noise emissions. This is important for airlines to meet future regulations.

No Airplane For The UltraFan 80 Yet

While Airbus and Boeing have publicly announced next-generation replacements for their narrowbody aircraft (discussed below), a curious detail is that there is not yet any known use case for a widebody UltraFan. This means that Rolls-Royce is developing an engine in anticipation of new widebody aircraft.

This makes it more difficult to discuss the aircraft that the UltraFan 80 will power. However, an intriguing possibility is the potential Airbus A350-2000 stretch. Airbus is currently studying stretching the A350-1000 to better compete with the incoming Boeing 777-9. At this point, the program is not committed, although it is serious enough that Airbus has publicly stated it is investigating it and Emirates has already expressed interest in buying it.

It is also far from clear if a future A350-2000 would even come with the UltraFan 80; it is perhaps more likely it would instead get a variant of the existing Trent XWB already powering the family. Rolls-Royce's current description calls the UltraFan 80 "the blueprint for the next generation of widebody applications."

Reading between the lines, it is possible this signals RR is developing the engine for new, currently unannounced widebody aircraft, not just upgraded or stretched A350s, 787s, or 777s. In July 2026, The Guardian reported that Rob Watson, Rolls-Royce’s President for Civil Aerospace, had said that "the reality now on the large engine is going to be driven by the next widebody platform."

UltraFan 30 Is Likely More Strategically Important

It's perhaps somewhat ironic that the widebody UltraFan 80 is in a more advanced stage of development and lacks obvious applications, while the narrowbody UltraFan 30 is further behind in its development but has obvious applications. The 30,000 lbf UltraFan is still in the concept stage, with Rolls-Royce planning to build and test it by 2028.

In fact, the 30 is arguably the more strategically important program for RR. It is being developed specifically for the future single-aisle market. The two main narrowbody engine rivals are Pratt & Whitney and CFM International (a Safran and GE Aerospace joint venture). CFM has already announced its program to develop the open fan CFM RISE for the next generation of Airbus narrowbody aircraft.

This would represent a significant change in engine design over today's engines. It could offer significant savings, but it may also be riskier. RR may be able to position its 30 as a more conventional and less risky solution for future narrowbody aircraft, although this remains speculative.

Airbus appears to be further along the development track to replace its A320 than Boeing, although the mid-2030s is likely the earliest realistic time that it could enter service. Currently, it doesn't appear Airbus or Boeing are interested in another upgrade of their respective A320s and 737s, meaning the UltraFan 30 is likely intended for a clean-sheet aircraft, not a 'neo'.

A Forward-Looking Family Of Engines

For decades, Rolls-Royce's widebody engines have been an evolution of its successful Trent series. UltraFan offers new architecture and lightweight composite materials, allowing it to spawn a new generation of geared turbofan engines. The engine is being designed to be compatible with 100% sustainable aviation fuels.

Meanwhile, Rolls-Royce is also exploring hydrogen and hybrid-electric as alternative forms of power. Also, importantly, the UltraFan is more than just a next-generation family of engines. RR says there is the potential to transfer technologies from UltraFan to current in-service engines to provide more fuel efficiency and reductions in emissions.

Put another way, while the UltraFan may never power aircraft like the A330neo, it may still make them a few percentage points more fuel efficient. RR's advertising material appears to imply the UltraFan 30 would offer considerably more savings than the larger UltraFan 80.

The 80's target is to deliver around 10% efficiency savings compared with Rolls-Royce's benchmark XWBs. Rolls-Royce says the UltraFan 30 could deliver a 20% fuel-burn improvement relative to ‘current in-service engines’. The company does not, in the material cited here, specify a single engine benchmark, so this figure should not be interpreted as a direct 20% reduction against the latest-generation LEAP or PW1100G without further qualification.