Airbus is planning to apply for funding from the new Clean Aviation program to develop a successor to the wing program that is currently tested on a C295 testbed. The follow-on program should research wings for future hybrid-electric or hydrogen airliners. Airbus plans a follow-up on semi-morphing wing program. The European airframer signaled its interest during last week’s Clean Aviation Forum. During the event, José Luis Lopez Diez, Head of Architecture and Integration of Airbus Defense and Space, gave a short update on the wing program that has been flight-tested since late January. The Spanish-build C295 Flight Test Bed 2 has done some twelve flights in the South of Spain as part of a technology program under the European Clean Sky 2 research program. While the C295 is a medium-light military tactical transport aircraft, it is testing technologies that could be useful for future commercial aircraft designs. Of special interest is the so-called semi-morphing wing with newly designed wing elements and winglets. The primary flight controls like the ailerons, flaps, slats, and even the winglets feature improved aerodynamics and are adjustable in flight, thanks to five, digitally controlled, electromechanical actuators. As they adjust their shape, the wing segments improve the efficiency of the high-lift system and reduce fuel consumption. The test aircraft also has a newly designed Satcom-antenna, which instead of being a bubble on the fuselage is fully integrated in the airframe design. This drastically improves aerodynamics. Slide from Lopez Diez's presentation, showing the different electromechanical actuators in the C295 wing. (Airbus) Airbus says that the wing technologies could help to reduce fuel burn/carbon dioxide emissions by 43 percent and nitrogen oxide emissions by even 70 percent on a typical Search and Rescue (SAR) mission of a C295. On a typical, 1.000 nautical miles commercial flight, CO2 emissions would be seven percent lower and NOX by 49 percent. Lopez Diez said that during the flight tests, “the handling quality of the plane was really, really good, as expected, and even more. The pre-flight simulation was quite close to the real flight, which is really important for us and all the 112 people who are working on this program.” With each flight, the team works to finetune and expand the flight control laws at both low and high speeds, while also checking the performance of the antenna. Extensive tests with the new wing elements and actuators are scheduled for the next two years when the development work continues even as Clean Sky 2 has been officially closed. Part of the system too is a new high-voltage, direct currency 270 volts system to power the electromechanical actuators. A ground demonstrator is being tested in Getafe and will be integrated into an actuation rig. Airbus will start testing resin infusion for wing elements from the middle of this year. (Airbus) The C295 project is not just about the wing systems, but also about the wing design, materials, and manufacturing. “We are preparing a ground demonstrator for a new technology of manufacturing, which will see the liquid resin infusion of thermoplastics. This will allow us to reduce the weight of the wing by around ten percent”, said Lopez Diez. The new production technique not only makes the wing lighter but also has another advantage: “We are going to reduce the lead time for manufacturing by around thirty percent.” Liquid infusion is used on the wings of the Russian Irkut MC-21 and has the advantage of not requiring an autoclave. Spirit AeroSystems has recently started using resin transfer molding technology for the production of spoilers for the Airbus A320neo-family. The Spanish team wants to take it a step further. By the middle of this year, it has planned the production of the first resin-infused lower wing segment. This will be followed by an upper skin element in the third quarter and a full-scale specimen in the fourth quarter. Extensive tests of the skin elements and the composite wing box are planned for the first half of 2023. José Luis Lopez Diez shows a slide with potential applications for new wing technology. (Airbus) The work doesn’t stop here, said Lopez Diez. Airbus Defense and Space is planning to apply for additional funding under the new Clean Aviation program, which called for proposals during last week's forum. Lopez Diez said that a follow-on program is very interesting when developing new wing concepts not only for the next generation of aircraft that enters service in the 2030s but notably for future electric and hydrogen aircraft. “Based on the very good results that we have already demonstrated in Clean Sky 2, we consider that we can go a step further for different configurations with hybrid-electric systems, in order to not only improve the aerodynamics but also the fuel consumption to allow us to get to around fifty percent lower CO2 emissions. That is key for us and that’s why we are preparing to make our offer within the next three months to continue these activities in parallel with Clean Sky 2.”
