Enhancing climate compatibility for commercial aircraft through intelligent load control

"Thanks to an ingenious combination of sophisticated control surfaces and modern sensors, we can better absorb turbulence, minimise the load on the aircraft structure and thus develop more efficient aircraft," explains Lars Reimer, project manager at the DLR Institute of Aerodynamics and Flow Technology. This is achieved, among other things, with laser systems and LiDAR sensors, which use lasers to measure wind patterns and detect oncoming gusts early on. These sensors enable the aircraft to react even more precisely and proactively to external influences, automatically adjusting control surfaces such as rudders and flaps. "The use of state-of-the-art load control systems not only reduces material stress and extends service life, but also improves the aerodynamics and efficiency of modern commercial aircraft," Reimer continues.

Simulations and tests confirm great potential

In the oLAF project, DLR researchers investigated how the comprehensive use of load control technologies affects the design of new long-haul aircraft. To accurately assess the potential of the technology, they used multidisciplinary numerical simulations to develop two aircraft designs with identical requirements and then compare them. One aircraft was designed with conventional technology, while the other was consistently designed with state-of-the-art, 'aggressive' load reduction from the outset. The crucial difference: the new technology enables wings with a greater span and higher aerodynamic efficiency – a paradigm shift that significantly reduces fuel consumption and emissions.

To verify these results, researchers from the DLR Institute of Aeroelasticity conducted experiments in the Braunschweig Low-Speed Wind Tunnel (DNW-NWB). They equipped a wind tunnel model of a flexible wing with movable trailing edge flaps and spoilers and used a specially developed mobile gust generator to create artificial bursts of wind. The vibrations on the wing were measured both with and without load control activated. The results show that with load control the vibrations were effectively reduced and the stress at the wing root was reduced by up to 80 percent.

More efficient wings with modern load control

Findings from the simulations and tests demonstrate that when comprehensive load control is integrated into aircraft design, it enables lighter, higher-aspect-ratio-wings with superior aerodynamics and fuel efficiency. Aircraft with this new technology are estimated to consume up to 7.2 percent less fuel and can increase cost-effectiveness by up to 6.7 percent, despite possible additional maintenance costs. "We were surprised by the results," says Reimer. "Initially, we saw load control primarily as a method for reducing weight, but now it seems to be a key element for future wing design – with significantly improved aerodynamics and greater efficiency."

Next steps: taking the technology to the skies

DLR now plans to further develop the technology and test selected prototypes in research aircraft. Meanwhile, the researchers are continuing the work started in oLAF by refining the digital design process, integrating all relevant disciplines – from aerodynamics and structural engineering to load control. The goal is to provide aircraft manufacturers with a methodology and highly precise tools that can be used to incorporate load reduction technologies from the earliest stages of development.

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