…the design of the full development A3XX wing was a collaborative effort involving wing experts throughout Airbus.
The design lineage therefore extends back through the A300 to the de Havilland Comet, Trident and Sud Aviation Caravelle, and through the A310 and A320 – it even incorporates elements from the VFW614. Thanks to experience with the A320 and A330/A340, the design also built in both aerodynamic and structural heritage features from the BAC series, including the use of integrated machined outer wing panels similar to those originally designed for the VC10 and One Eleven.
“One thing was to go to a completely sealed slat system, but we couldn’t do that because of [design patents held by] Boeing, and our wing was still stalling between the engines and not near the root,” says Ogilvie. The depth of the wing root, almost 3m at its deepest section, meant that the wing was too fat for a conventional Kruger flap to work. “So how could we do a sealed slat that wasn’t sealed?” Ogilvie asked.
The answer was the droop nose, a device developed for the Trident, which is permanently sealed. “The rotation point is within the wing profile and in its high-lift configuration it meets the requirement for maximum lift, but has substantially better drag. And it stalls inboard because it doesn’t have a slot,” says Ogilvie, adding that Airbus has subsequently filed a patent for the design.
Externally, the most distinctive aspect of the wing, aside from its size and 79.7m span, is the pronounced “gulling’”effect and its 5.6° dihedral. “This was set by the stability requirements of the aircraft. We didn’t want it too high, making it too stable, or too low, making it unstable. Plus, we needed to set it for adequate engine ground clearance, particularly in the case of the aircraft rolling around on its undercarriage. Everyone’s seems to have those images on their desktop computer of that Boeing 747 landing badly at Hong Kong, scraping its engines – that’s what we wanted to avoid,” says Ogilvie, who adds that the gulling also uncovered a potential problem.
