“There has never been a more exciting time in my 25-year career as an aerospace engineer,” said GE Aerospace General Manager of Advanced Technologies Arjan Hegeman yesterday in remarks before the Senate Committee on Commerce, Science and Transportation. The hearing, on “Advancing Next Generation Aviation Technologies,” was part of the Senate’s work on the 2023 FAA Reauthorization Act. “This era of innovation requires ongoing collaboration with federal agencies like NASA and the FAA,” Hegeman said. (View the full session here.)
Currently GE Aerospace is carrying out one of the company’s most extensive technology development roadmaps in its more than 100-year history. Multiple ground and flight tests planned this decade will seek new breakthrough technologies for use in next-generation commercial aircraft engines that could enter service beginning in the mid-2030s.
Advanced engine architectures such as open fan, hybrid electric propulsion systems, and new compact engine core designs — just some of the technologies that will be demonstrated on test stands, ground tests, and flight tests over the coming years — are all key programs to watch.
In addition to maturing these technologies for flight readiness and new products, GE Aerospace also supports efforts to increase use and availability of alternative fuels, such as sustainable aviation fuel (SAF) and hydrogen.
Revolutionary technologies and alternative fuels both have critical roles to play in meeting the aviation industry’s long-term climate goal of net-zero carbon emissions by 2050 for commercial flight.
Here, we’ve laid out GE’s top innovations and industry-leading efforts to watch in the march toward net zero.
Open Fan and the CFM RISE Program
Hegeman and other GE Aerospace engineering leaders believe the time for open fan is now. Why? Since GE first flew an unducted fan in the 1980s, the open-fan engine design has been made simpler and lighter with new approaches such as single-stage rotating carbon-fiber composite fan blades and stationary outlet guide vanes. Learn more here.
The open-fan design is one of the advanced engine architectures CFM International, a 50-50 joint company between GE and Safran Aircraft Engines, is exploring through the CFM RISE Program. The parent companies came together in June 2021 to unveil the RISE Program with a target of more than 20% better fuel consumption and lower CO2 emissions than in today’s most efficient engines. Technologies matured as part of the RISE Program will serve as the foundation for the next-generation CFM engine that could be available by the mid-2030s. Central to the program is state-of-the-art propulsive efficiency.
A More Electric Future of Flight
Even before NASA announced in September 2021 the selection of GE Aerospace for its Electrified Powertrain Flight Demonstration (EPFD) program, GE had been advancing electrification of aircraft and engine systems for more than a decade. During that time, GE engineers matured individual components of a hybrid electric system, including motors, generators, and power converters.
Now the jet engine maker and aircraft systems company will take what it’s learned in laboratories about making an integrated electric machine and ready it for ground and flight tests planned for the mid-2020s.
Through the total $260 million program with NASA, GE Aerospace is maturing a megawatt-class hybrid electric powertrain to demonstrate flight readiness for single-aisle aircraft using a modified Saab 340B test bed and GE’s CT7 turboprop engines. GE is partnering with Boeing, which will support the program’s flight tests, and has selected BAE Systems to design, test, and supply energy management components.
Smaller Core, Greater Efficiency
One of the enabling technologies being studied in CFM’s RISE Program is a compact engine core. In another multimillion-dollar program with NASA announced in late 2021, GE Aerospace was awarded contracts to test and mature new jet engine core designs, including compressor, combustor, and high-pressure turbine technologies to improve thermal efficiency. Continued development of ceramic matrix composites, an advanced, heat-resistant material, is also a key part of the effort to improve fuel efficiency and thereby reduce emissions. GE Aerospace expects this effort to lead to a ground test later this decade.
Powering Multiple Firsts for Sustainable Aviation Fuel (SAF)
For more than a decade, GE Aerospace has supported multiple flight demonstrations with SAF. This work includes the industry’s first commercial demonstration flight of biofuel, in 2008, using a Virgin Atlantic Boeing 747 powered by GE’s CF6 engines; the first commercial airliner flight with 100% SAF in both engines, on the 2018 Boeing ecoDemonstrator, a FedEx Express Boeing 777 powered by GE90 engines; the first passenger experimental flight with 100% SAF in one of the two engines, in 2021, using a United Airlines Boeing 737 MAX 8 powered by CFM LEAP engines,* and the first demonstration flight in the Middle East using 100% SAF in one of the two engines.
All GE Aerospace and CFM International engines can operate on approved SAF blends today, which can be made from plant-based material, fats, oils and greases, alcohols, waste streams, captured CO2, and other alternative feedstocks. SAF has the same chemical composition as the jet fuel most commonly used today. The key difference is that instead of being made from fossil-based sources, SAF is made from more renewable sources. The use of alternative feedstocks and processes reduces life-cycle CO2 emissions during production, processing, and distribution compared with fossil-based fuels.
Additionally, all SAF approved today is drop-in, able to replace conventional jet fuel, requiring no changes to aircraft equipment or fueling infrastructure to use it.
“We have very clear goals, and very ambitious ones,” said Zeina Chakhtoura, senior customer support manager for GE Aerospace. “We are industry leaders when it comes to pushing for SAF and decarbonization in general, by leveraging existing technology and inventing the future of flight.”
Pioneering Hydrogen Combustion
The announcement made in February 2022 that CFM and Airbus are collaborating on a hydrogen demonstration program will be informed in part by GE’s experience with hydrogen fuels in land-based gas power turbines. GE has more than 8 million operating hours of experience with hydrogen fuel blends, including with aeroderivative engines.
With plans to flight-test a hydrogen combustion engine around the middle of this decade, CFM’s RISE and Airbus’s ZEROe programs come together.
CFM will modify the combustor, fuel system, and control system of a GE Passport turbofan to run on hydrogen. The engine was selected because of its physical size, advanced turbo machinery, and fuel flow capability. It will be mounted along the rear fuselage of the flying test bed to allow engine emissions, including contrails, to be monitored separately from those of the engines powering the aircraft. CFM will execute an extensive ground test program ahead of the A380 flight test.
“We will fly a modified engine to learn the art of the possible and to prove out the technologies,” said Mohamed Ali, vice president and general manager of engineering for GE Aerospace. “Is hydrogen harder? Yes. Is it doable? Absolutely. And we are building on tremendous experience, and I am actually very encouraged by the inventions we have already made to address those challenges.”
* LEAP engines are a product of CFM International, a 50-50 joint company between GE and Safran Aircraft Engines.
With the summer holiday season underway, air travel has bounced back from its lockdown doldrums. But so has the awareness of commercial aviation’s impact on the climate.
Airlines and aircraft and engine manufacturers want to be part of the conversation.
Take Airbus and CFM International, a 50-50 joint company between GE and Safran Aircraft Engines. In February, the two companies announced plans to collaborate on tests of an aircraft engine fueled by hydrogen. And this week at the Farnborough Airshow, Airbus said it would join the cause along with CFM by participating in the RISE (Revolutionary Innovation for Sustainable Engines) Program, launched in 2021. The technology development initiative aims to mature and demonstrate advanced technology that would serve as the foundation for the next-generation CFM engine that will use 20% less fuel and create 20% fewer emissions than the most efficient jet engine in use today and could enter service by the mid-2030s.
In the second half of this decade, the aircraft manufacturer will partner with CFM to carry out a flight test demonstrator program on an Airbus A380 to validate the open-fan engine architecture.
Airbus, CFM, GE and Safran have joined the Air Transport Action Group’s goal to achieve net-zero carbon emissions in aviation by 2050. “We have a vision and commitment to help the industry achieve its net-zero goals,” says Gaël Méheust, president and CEO of CFM International, “and the open-fan flight test demonstration program is an exciting step toward achieving that.”
The fan at the front of this architecture is “open” because, unlike other turbofan engines, it isn’t surrounded by a case. This reduces weight and enables the fan blades to be a good deal larger. As a result, the fan can move much higher volumes of air around the engine, rather than through the engine core.
The difference between these two volumes is called bypass ratio. It’s an important number that describes engine efficiency. CFM engines have grown from an initial bypass ratio of 5:1 in the 1980s to the LEAP engine, which has a bypass ratio of 11:1. An open fan could achieve a bypass ratio above 70:1. And this translates to a 20% reduction in fuel and emissions compared with the most advanced engines flying today. Hybrid electric propulsion and sustainable aviation fuel could lead to even deeper emissions cuts.
CFM has been seeking to build ever more efficient products since the company’s first CFM56 engines entered service in the early 1980s. Since then, its engineers have been able to reduce fuel consumption and CO2 emissions in CFM engines by 40% compared with the engines they replaced.
The news at the Farnborough Airshow represents a homecoming of sorts for the design. The industry started studying the open-fan concept first in the mid-1980s when GE and Safran developed and tested the GE36 engine, also known as the unducted fan engine (UDF). A McDonnell Douglas MD-80 plane powered by a GE36 landed at the Farnborough Airshow in 1988.
The GE36 helped mature key engines technologies such as lighter and stronger fan blades made from carbon-fiber composites.
“That technology was initially tested on the GE36 before making its way onto the GE90 in 1995 and, later, the GEnx and CFM LEAP engine families,” Méheust says.
In 2017, Safran and Avio Aero, a GE Aerospace company, also tested a counter-rotating open-rotor (CROR) engine — which has two rotors spinning in opposite directions — as part of the European Clean Sky sustainability initiative. The work allowed engineers to develop a new, quieter fan configuration.
The RISE open-fan demonstrator engine is being developed with just one large, efficient rotor, spinning at the front of the engine, with a row of stator (stationary) blades just behind.
Since CFM announced the program a year ago, the company has begun successfully testing various components. Ground testing of a fully assembled engine prototype is set to begin around the middle of this decade. Flight testing will take place through the second half of the decade — on GE’s 747 flying test bed in Victorville, California, as well as the A380 flight test program in Toulouse, France.
The aims of the flight demonstrator include gaining insights on how various wing aircraft installation options affect aerodynamic performance. Engineers will look for ways to sharpen the efficiency of the propulsive system, validate the 20% fuel efficiency gains and the improved acoustic models, and ensure compatibility with 100% sustainable aviation fuels.
Hydrogen fuel may also play a part in the eventual final product of the RISE Program, and Airbus is helping out there as well. In February 2022, the two companies announced a joint flight test program to explore ways to use 100% hydrogen, a low-carbon fuel source, to fly a plane.
In addition to the paradigm shift of freeing the fan blades from their housing, other breakthrough technologies, like ceramic matrix composites, are playing a significant role in the RISE Program. Already flying in today’s LEAP engines, this material is one-third the weight of steel but can withstand temperatures as high as 2,400 degrees Fahrenheit, beyond the melting point of many advanced metallic superalloys. That increase in temperature improves an engine’s thermal efficiency. In addition, dozens of other components will be 3D-printed, or additively manufactured, which is faster and less expensive than traditional subtractive methods. This manufacturing technology frees the design space for engineers, enabling them to create more organic designs that are not limited by the capability of machine tools.
For CFM, the program represents a chance to create a generational shift that redefines flight for decades to come. Says Méheust: “It’s all about pushing the technology envelope, redefining the art of the possible, and helping to achieve more sustainable long-term growth for our industry.”
Alex Hills developed a passion for 3D printing like most hobbyists: He bought a printer and began “tinkering around” with some simple print builds.
A decade ago, Hills, who works as a test hardware engineer at GE Aviation, printed his first generic jet engine design from plans he found online. “It was a real simple model that spun with some bearings,” he says. “I thought it was cool and printed another one that I put on my desk.”
The degree of difficulty of his projects rose along with his skills. He spent six months building a pair of six-foot Saturn V rocket replicas for the National Museum of the United States Air Force in Dayton, Ohio. “I’ve been a volunteer there for 14 years and have been coming up with STEM projects for education and family events,” he says. “That project gave me a lot of experience and technique.”
He’s gotten so good over the years that he can now bring this experience to work, including in some of the most advanced projects. In June 2021, he watched a detailed video about CFM International’s newly announced RISE technology demonstration program, which aims to develop technology for engines as much as 20% more fuel-efficient than the most advanced engines currently in service. (CFM is a 50-50 joint venture between GE and Safran Aircraft Engines.
One component of the RISE project is the open-rotor concept — an idea that keeps the engine fan blades on the outside of its body rather than covered, as is common with jet engines today. The design could lead to fans with diameters as large as 12 feet and potentially dramatically increase the engine’s efficiency. “I wanted to build something that represents what I’ve worked on,” he says. I thought it would be great to build an actual model of the open fan, so I began reverse-engineering the design in software for 3D printing.”
Hills never printed a project without plans prior to this endeavor, let alone an architecture that was so challenging. But the video helped him piece together instructions for his printer. “The video gives you straightforward images of the concept. I roughly scaled things on how big the engine would be based on what information was out there. I was able to develop a model from that,” he says.
Hills worked on the fan first. “It’s a real interesting fan,” he says. The fan blades of even the most advanced jet engines remain at a fixed pitch — kind of like the blades inside the fan you have at home. But the RISE project is seeking to change that. “For this engine, since it’s unducted, to get reverse thrust capabilities you have to pitch these blades, and you can see they rotate on the hub. That’s something that is used on turboprops. It was a challenge.”
After many hours of toying with dimensions and generating a design, Hills finished his first open-fan model last fall. Instead of displaying it on his desk, he donated it to GE’s Cincinnati-based Community Service Fund, and the model was auctioned off for $900.
Word of Hills’ feat spread quickly through the company, all the way to Chris Lorence, chief engineer and general manager for GE Aviation. Lorence, who was preparing for an industry sustainability conference in Europe, was looking for a prop that would easily communicate to his listeners what the advanced open fan was. Sure, there were videos to illustrate the concept, but once he saw Hills’ model, Lorence knew he had found a solution.
Hills turned on his printer, and 10 days later he handed Lorence a new model, just in time for his trip. “The paint was still drying!” Hills laughs.
At the conference, the model performed as designed. “It turned out to be a great way to let people see what we are talking about with these technologies,” Lorence says. "Pictures and videos are just not the same as the tactile element of being able to get up close to a model of the engine to see what we are talking about, particularly something as innovative as the RISE open fan, which is so different from what we’ve done historically in the industry.”
Hills keeps refining his models. His latest tweaks include magnetic, removable rotor blades, a gearing mechanism for the stators and fan blades, and a more detailed core of the engine concept with LED lights. He even pairs the finished product with jet engine sound recorded from a GE90 — the most powerful commercial jet engine in service — starting up and shutting down. Eventually, Hills plans to design a pylon attachment that would hook onto a wing model.
“One of the great things about Alex and the engineering team here at GE is they have such a passion for our product,” Lorence says. “It goes beyond the design work and the day-to-day challenges. People here get very excited about inventing the future. Alex is a great example of how that enthusiasm can reach beyond the workplace."
It’s been four years since aviation fans, industry executives, aerospace engineers and investors last descended on the local airport in Farnborough, a quiet town about an hour southwest of London. Normally, the Farnborough International Airshow takes place every two years, alternating with the Paris Air Show. Together, they are the focal point for the aerospace industry. The pandemic disrupted this rhythm, but starting Monday the Farnborough show is back on track.
Farnborough allows aviation watchers to take stock of the latest developments in the industry. Airlines come here to purchase new planes and engines for their fleets. Aircraft builders unveil their new plans, and engine-makers, like GE, display the latest technologies. Despite the pandemic disruption, this year is no different, and GE Reports will be on the ground to tell you all about it.
But even before we got on the plane to England, we went to GE Aerospace, one of the largest engine-makers in the world, and asked them what they are bringing to the show. The company is a good place to start, because a commercial plane powered by GE Aerospace or one of its partners takes off somewhere in the world every two seconds.
One topic dominating the air-show agenda is innovation, and GE is ready to lead the conversation, from the engines designed to use less fuel it is delivering for customers today to the breakthrough technologies it is pursuing for a more sustainable tomorrow. Last year, CFM International, a 50-50 joint company between GE and Safran Aircraft Engines, launched the Revolutionary Innovation for Sustainable Engines (RISE) Program with the goal of developing advanced technologies for the next generation of engines that will use 20% less fuel and produce 20% fewer CO2 emissions than the most efficient jet engines built today.
This project is working with so-called open-fan architecture, an engine design that GE — and Farnborough — have tested before. In 1988, GE’s experimental “unducted turbofan” engine, called GE36, stole the show when a McDonnell Douglas plane powered by it completed the first transatlantic flight.
The engine helped GE pioneer innovative technologies like rotor blades made from carbon-fiber composites. These blades and materials allowed GE to build larger, lighter and more fuel-efficient engines and gave birth to a line of GE Aerospace’s high-bypass jet engines, including the GE90, the GEnx and the GE9X, now the world’s most powerful jet engine.
The GE90 and the GEnx are on display here this year, as is their cousin the LEAP engine, developed by CFM. The LEAP engine, which also features 3D-printed parts and components from other advanced materials, is the fastest-selling engine in aviation history. The technologies help make the engine 15% more fuel-efficient than its predecessor, the CFM56. This is important because fuel costs now represent about 24% of airlines’ overall costs.
CFM and Airbus also announced they’ll collaborate on tests of a GE aircraft engine fueled by hydrogen. Around the mid-2020s, the team plans to mount the engine on a modified Airbus 380 for flight testing, with the goal of placing a hydrogen-powered passenger plane into service about 10 years later. Such a plane would produce zero CO2 emissions during flight.
Further on the horizon is the work GE engineer Christine Andrews and her team are doing. They are collaborating with NASA and Boeing to develop a technology demonstration of a hybrid electric engine for commercial aircraft. The project could help GE Aerospace reach its goal of net-zero CO2 emissions for its sold products by 2050. GE Aerospace has been working on hybrid electric systems for more than a decade. The goal is to put everything together by the mid-2020s for ground and flight tests of a megawatt-class hybrid electric propulsion system. “Once we go electric, we are never going back,” she told GE Reports.
Expect GE and others to also address sustainable aviation fuel, or SAF. Last December, United Airlines became the first carrier to operate an experimental passenger flight using only SAF in one of its engines. This is a big deal. By switching from petroleum to SAF — when you take into consideration the entire life cycle of the fuel — the aviation industry could reduce its carbon contribution from fuel by up to 80%, according to the Air Transport Action Group and the International Air Transport Association. “Stopping climate change and achieving environmental sustainability is imperative, it’s possible, and I plan to do everything I can to help,” said Jeff Shaknaitis, who had a seat on the flight and who now leads customer sustainability programs at GE Aerospace.
Finally, there’s software. Aviation algorithms from GE Digital are already helping airlines navigate the course for “the perfect flight,” an effort aiming to help them operate at their peak efficiency and reduce their carbon emissions at the same time. Using fuel smartly and being able to measure the savings is an important part of that journey. If “you fly two planes to Atlanta three times a day, data can tell you that one has a very different CO2 profile,” says Andrew Coleman, who runs GE Digital’s aviation software business. “Maybe you carried too much fuel and all that extra weight made your fuel consumption and emissions go up. It can be a million things, and we can help you find out what it is.”
Farnborough is the perfect place to talk about the future, as the airport is steeped in aviation history. The American-born aviation pioneer Samuel Cody completed the first powered flight in Britain at the Farnborough airfield in 1904. Queen Elizabeth II visited here in the 1960s to look at early designs for the Concorde, the first and only supersonic passenger jet to enter scheduled service.
GE has been coming to Farnborough since it first opened its gates in 1948. We will make sure that in these pages, in our newsletter, the GE Brief, and on LinkedIn that you know what it has to offer this year, even if you can’t make it.