Airbus is approaching a critical design review for heavy modification to an A340-300 test aircraft which will enable exploration of high-speed laminar flow, one of the promising technologies for future configurations.
The Breakthrough Laminar Aircraft Demonstrator in Europe (BLADE) testbed will feature laminar-flow wing sections outboard of the outer engines. Each will have a shallower sweep, giving the A340 a distinctive kinked wing planform.
Airbus head of environment engineering Rainer von Wrede said, of laminar flow, that the "idea is very old" but that taking advantage of it required high quality wing surfaces: limited stepping, low waviness from manufacture or cruise-load deformation, and minimal three-dimensional disturbance from insects or fasteners.
The airframer, which is co-operating with Saab on the project, said the A340 demonstration, part of the Clean Sky environmental programme, "will be the most important step for application of such technology in the future". Critical design review for the modification will be completed in December this year.
Von Wrede says laminar flow is one of several technological advancements in Airbus's research portfolio as it looks to aircraft design in 2050.
"It doesn't make sense to base decisions only on technology and availability," he said, adding that the manufacturer needs to ensure that the technology is applicable.
This demand for maturity will govern the arrival of new configurations, he said. Relocating engines on the top of the rear fuselage would have a "huge impact on noise reduction". But certain configurations require reliability "beyond what we have today".
"Classic configurations won the game [for current designs]," he said. "One day a different configuration will be the winner."
Airbus's concept aircraft are designed to "give an image of some of the things we think about", said von Wrede. The airframer is "striving for more electric aircraft", requiring examination of alternative energy sources such as fuel cells - which, he says, are "not far from being better than auxiliary power units" - and the possibility of more localised energy generation, perhaps even from the heat produced by passengers which is currently "thrown away".