Aerospace Project Intelwi develops intelligent airplane wing

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DLR Deutsches Zentrum für Luft- und Raumfahrt e.V. Institut für Verkehrsforschung

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Wuxi InfiMotion Technology Co., Ltd.

At first glance, aircraft wings have barely changed their shape and size over the last 60 years. However, they play a major role in the path to climate-compatible aviation. The Intelligent Wing project, shortly Intelwi, is investigating what an efficient aircraft wing of the future would have to look like.

When looking at the currently common aircraft wings, it quickly becomes clear that they would be more efficient if they had a larger wingspan. But an increase in wingspan makes the wings more prone to gusts that occur during flight. Such a wing would therefore have to be constructed more stably. As a result, it would be significantly heavier. This is exactly what a solution was worked out for in the Intelwi project.

Use of intelligent control systems

"Our aim was to design a wing that has a higher aspect ratio, i.e., is significantly slimmer than previous wings," explains Dr. Tobias Wunderlich from the DLR Institute for Aerodynamics and Flow Technology. "We have designed several wing models and examined them in simulations to find out how the loads acting on the wing can be reduced and can exhibit less resistance despite a significantly greater deflection." Intelligent control systems are supposed to help in this and autonomously react to external influences such as maneuvers and gusts with load reductions. An example: the researchers scan the air in front of the aircraft with a LIDAR system and send signals to the flight control. In case of a gust, they can immediately deflect the control surfaces to reduce the loads and improve passenger comfort. The control surfaces are also used to minimize the resistance that occurs at higher flight speeds or at different flight altitudes. Because the wing curvature is automatically adjusted to the flight state, this is referred to as an adaptive wing.

In total, seven DLR institutes and other project participants, including Airbus as the overall project manager, analyzed the maximum achievable performance—mass, resistance, lift, faults, and maintenance intervals - of a highly stretched, flexible, intelligent wing. There was a special focus on the interaction between the disciplines involved. This led to a better understanding of the whole system. They used precise and fast simulation methods to improve and accelerate the development process of the wing and thus to advance digitization across the board. After a runtime of three and a half years, the project from the Federal Aviation Research Program (LuFo VI) has ended.

Five percent fuel savings

Initial evaluations are already available. "In the end, we opted for the design of a wing with an aspect ratio of 12.4. This wing of a long-haul commercial aircraft seemed very promising," says Wunderlich. One would have to imagine it 30 percent slimmer than usual. Based on this wing, a detailed design of the entire aircraft was produced according to the current state of the art. The consortium partners received this as a reference aircraft. The wing was then equipped with the new technologies —i.e., with multifunctional control surfaces, centralized and decentralized control and regulator systems, local sensors and extended functions of the flight controller for gust and maneuver load reduction—and examined in detail. "It is not yet possible to say exactly when these technologies will be ready for series production," says Wunderlich. But it is already evident how effective the use of the technologies of the adaptive wing is. Using the control surfaces to reduce air resistance in cruising flight would save one to two percent in kerosene consumption. During maneuvers, the loads acting on the wing could be reduced by targeted control surface deflections at the trailing edge to such an extent that four percent of fuel could be saved compared to the reference aircraft in combination with the improvements in cruising flight. And that, even though the reference aircraft, with which the data was compared, was already significantly more sustainable and economical than today's commercial aircraft.

Reduce fuel consumption

Such an "intelligent wing" can be considered a consistent next step in development for future commercial aircraft. It will play a decisive role in securing the future competitiveness of the overall consortium leader Airbus as an aircraft manufacturer and the system suppliers as a supplier industry. In addition, it will increase performance and thus significantly reduce the fuel consumption of future aircraft. "Of course, there are still many open questions, but all the examined technologies have every prospect of being used in future aircraft. We expect that the wings of new machines will be load-adaptive wings with a significantly higher aspect ratio," Wunderlich concludes. (se)