Gulls’ wings offer inspiration for variable-geometry aircraft

Birds have always been an obvious inspiration for humanity’s attempts to design aircraft, but despite centuries of invention, we have never been able to directly utilise the techniques or material adaptations which birds use to fly. Zoologists from the University of British Columbia (UBC) in Vancouver have now discovered how the relatively-simple wing joint in seagulls helps the birds to stabilise their flight, and they believe that this could be mimicked by engineers to design aircraft that can dynamically adjust their wing shape to cope with challenging flying conditions.

“It’s not enough that those two seem to produce sufficient lift and thrust,” explained researcher Christina Harvey, who has now moved from UBC to the University of Michigan. “They must also control and stabilise their flight paths to be able to successfully forage and migrate in the natural habitat.” Seagulls – which contrary to popular belief are not seabirds as they live on land, albeit on the coast, seabirds spend most of their time in the open ocean – often encounter turbulent air flying near buildings or cliffs, or fly through convective airflows over open water. To cope with this, Harvey and research leader Douglas Altshuler explain in a paper in the Journal of the Royal Society Interface, the birds alter the angle of the elbow joint to pull the tips of their wings in and back. This flexed shape gives them more control over flight through turbulent air.