The challenge was looming..They knew, and so did everyone else, that commercial aviation is one of the most CO2 emitting industries in the world..Various efforts to reduce the industry's emissions, or reduce them to zero, has become a prime objective..Consider in the next 10 to 15 years the amount of aviation travellers could double, thus the need for efficient, clean running jet engines..It all goes back to 2014, when chief engineer Chris Lorence was leading GE Aviation’s advanced technology team — a group of technical engineers whose sole role is to test the boundaries of what’s possible..While ideas such as hydrogen and electric power have been tossed around over the past decade — several airlines are pursuing the electric route, including United, Mesa and Air Canada — according to Lorence, they were probing the possibilities of improving fuel efficiency with the goal to see how far they could push the envelope..GE designed and tested open fan designs dating back to the 1980s and had advanced significantly on that work, but a counter-rotating fan was essentially a given at that point, he explained on the company's website..That’s when one of the engineers asked, “Why does it have to counter-rotate? What if it’s single stage?”."It was like a lightbulb went off," Lorence wrote. "One of those moments when you’ve worked on something for so long that you can’t see it any other way, and then someone did."."It wasn’t just a breakthrough, it was radical. A single stage fan that wasn’t simply a propeller, but rather one set of rotating fan blades with the same speed and performance of a counter-rotating fan.".As chief engineer of GE Aviation and a GE engineer for the last 27 years, Lorence watched how the industry incrementally improved fuel efficiency with each successive new commercial aircraft engine design.."But the push for 20% greater fuel efficiency in one generation? That's something different. Engineers like big challenges, and this is certainly one of them," he said.. Open fan engineOpen fan engine .As the latest part of this effort, Airbus and CFM International (a 50-50 joint company with GE) are collaborating to flight test CFM’s cutting-edge open fan engine architecture which looks like an old propeller engine, but is able to increase the engine capacity while reducing CO2 emissions..CFM International’s project, part of its Revolutionary Innovation for Sustainable Engine (RISE) program, will involve extensive ground testing, as well as real-world testing aboard a double-decker Airbus A380, the world's largest commercial airliner..According to Interesting Engineering, flight tests for the validation will be performed in the second half of this decade from the Airbus Flight Test facility in Toulouse, France..The second phase of the flight testings is expected to occur at GE Aviation’s Flight Test Operations Center in Victorville, Calif., in the second half of the decade..The flight test program will be actualized to achieve several objectives that could contribute to future engine and aircraft efficiency improvement:.1) Enhanced understanding of engine/wing integration and aerodynamic performance (thrust, drag, loads) as well as propulsive system efficiency gains;.2) Validating performance benefits, including better fuel efficiency that would provide a 20% reduction in CO2 emissions compared to today’s most efficient engines;.3) Evaluating acoustic models and ensuring compatibility with 100% Sustainable Aviation Fuels (SAF) and hydrogen..Airbus explains the pylon with the engine mounts and attachment will be jointly designed for minimizing weight and vibration transmission to the cabin, as well as engine system integration, SimpleFlying.com reported..The fuselage structure affected by the propulsion system impact will also be studied, as well as the impact of noise on the cabin. It's believed the new engine design will result in less noise.. CFM's open fan engine designCFM's open fan engine design .How does it work?.According to Flying magazine, the engineering behind the open fan concept involves counter-rotating fans and increasing the flow of thrust-producing cooler air through the engine..Eliminating the nacelle exposes the engine to cooler air, making the engine work less to produce thrust. As a result, an open fan engine would allow an aircraft to achieve the same speeds as conventional engines, while decreasing fuel consumption..No nacelle also means less weight — another fuel saver..In a nutshell, open fan architecture would allow engineers to increase the size of an engine and the quantity of cooler airflow through it — without increasing the airplane’s weight, Flying magazine reported. .The scimitar-shaped rotating fan blades will be made from woven carbon composites..It also interesting to note the GE carbon composite blades on its GE-90 and GEnx engines that respectively power Boeing’s 777-300ER and 787 airplanes have never had an incident of a fan blade breaking during more than 140 million flight hours in service..In addition to the open fan, the engine includes a suite of cutting-edge technologies..An intricately manufactured high-temperature engine core will feature advanced metal alloys and ceramics. An electric generator embedded within the engine will enable hybrid electrification..Mohamed Ali, vice president and general manager of engineering at GE Aviation, said each of these technologies is very challenging, “we are stretching ourselves.”.“There will be learnings, and maybe setbacks,” he said. “But we are resolute.”.CFM also established a full-scaled roadmap with more than 300 different components, modules and full-engine builds to test and mature the technologies..“New propulsion technologies will play an important role in achieving aviation’s net-zero objectives, along with new aircraft designs and sustainable energy sources,” said Sabine Klauke, Airbus chief technical officer..“By evaluating, maturing, and validating open fan engine architecture using a dedicated flight test demonstrator, we are collaboratively making yet another significant contribution to the advancement of technology bricks that will enable us to reach our industry-wide decarbonization targets.”.CFM’s latest engine — the LEAP, launched in 2008 — powers Boeing’s 737 MAX and about 60% of the rival A320 family of jets built by Airbus..Safran CEO Olivier Andries said given the expected steep rise in air traffic over the next decades, much more drastic progress is necessary if the world’s airlines are to meet their target of cutting total carbon emissions in half by 2050, Seattle Times reported..To achieve that even as the number of aircraft grows, “the next generation of airplanes must reduce emissions by 90% as compared with the current fleet,” Andries said..He added 40% is expected to come from new engine and airframe technologies, 40% from the use of sustainable fuels and 10% from streamlining air traffic flow..The project builds upon research funded by the US government a decade ago when GE conducted wind tunnel tests on open rotors with NASA and the Federal Aviation Administration.. A380 test bedA380 test bed
