Airbus has unveiled, for the first time in detail, a folding wingtip technology developed under its "Wing of Tomorrow" program for future generations of passenger jets. The project targets high-efficiency composite wings for future single-aisle aircraft.
The most notable feature of the program is that the new wings would be considerably longer than those on current passenger jets. A longer wingspan significantly improves aerodynamic efficiency, but it also creates a serious logistical problem, which Airbus plans to solve by making the wingtips foldable.
Why longer wings save fuel
Long, thin wings are not a new idea in aviation and are already common on gliders, where the design increases lift while reducing drag. Engineers call this a high aspect ratio, which allows an aircraft to generate the same amount of lift while using less energy.
This translates directly into fuel consumption. As wings get longer, the vortices that form at the wingtips and the induced drag they create are reduced, so the aircraft burns less fuel and produces lower carbon emissions. Airbus is aiming for double-digit percentage reductions in both fuel use and emissions with its new composite wings.
Airbus plans to use an Airbus A321neo demonstrator as its test platform, extending each wingtip by about five meters compared with the current design so the new wing geometry can be tested in real flight conditions.
Fitting into existing airports
Longer wings bring a major infrastructure problem. Single-aisle jets such as the Airbus A320 and Boeing 737 are currently designed around a wingspan limit of roughly 36 meters under international aviation standards, allowing them to use existing gates and taxiways at most of the world's airports. Airbus's new wings exceed that limit, meaning the aircraft would not fit into standard jet bridges and parking positions.
Rather than rebuild airports worldwide or restrict the aircraft to select airfields, Airbus plans to fold the wingtips upward after landing, bringing the wingspan back under current standards while still gaining the aerodynamic benefits in flight.
The engineering is complex. The hinges, actuators and support systems needed for the folding mechanism add weight to the wing and affect its aerodynamics, so Airbus must ensure the wing keeps its strength while safely carrying the extra loads the mechanism creates.
As a result, Airbus will not begin flight tests with folding wings directly. Over the next three years, the company will test demonstrator wings that do not fold but share the same aerodynamic properties as the future foldable design, allowing it to safely validate the new wing's flight performance and efficiency.
