A consortium of 40 industry and research partners tested an innovative system for reducing aircraft drag
How can the fuel consumption of aircraft be reduced? In addition to reducing the weight of the aircraft, reducing aircraft drag is one possibility. The AFLoNext project (Active Flow Loads & Noise Control on Next Generation Wing), in which 40 partners from 15 countries are conducting research with Airbus as the coordinator and with significant involvement from the German Aerospace Centre (DLR), takes a particular approach.
Potential for savings of up to nine percent
Hybrid laminarisation is the magic word. Tiny holes are drilled into the front edges of the wings or tail, and around this area a certain amount of the inflowing air is vacuumed away. This guarantees a laminar flow (or streamline flow) and it helps to reduce resistance. You have a laminar flow when there is no turbulence or cross flows.
"This Hybrid Laminar Flow Control (HLFC) can significantly reduce drag and along with that it can reduce fuel consumption, emissions of pollutants and energy costs," explains Dr. Heiko Baron Geyr from Schweppenburg from the DLR Institute of Aerodynamics and Flow Technology. The DLR expects savings of up to nine percent. At the same time, noise generation will be reduced.
Tested in practice for the first time
In the spring of 2018, numerous test flights of the DLR research aircraft A320 ATRA using a modified vertical stabilizer took place. The principle had proved its effectiveness 20 years earlier, but now it could be tested in practice for the first time. "The question was not whether the system works in principle, but more with how much effort or expense the HLFC system can be brought into play in the test flight and how it performs under real conditions," said Baron Geyr from Schweppenburg. Several test flights were carried out at different heights, speeds and angles and in different weather conditions.
The data generated during the trials is now being analysed and the technology will be tested for its feasibility in the mass production of aircraft. Of course, the hybrid laminarisation will not be limited to the vertical stabiliser. "The target application is the wing. Here, it is imperative to find a well-balanced optimum solution between aerodynamic performance, system complexity, weight and production costs”, emphasises Baron Geyr from Schweppenburg.