Boeing 787 Winglet Design: Eagle Wing Tips — Boeing / NASA (Richard Whitcomb)

Biological model: Soaring birds (Buteo and Aquila species)

Company: Boeing / NASA (Richard Whitcomb)

Large soaring birds like eagles and vultures spread their primary feathers into finger-like tips to reduce induced drag during soaring. Aircraft designers have mimicked this with winglets that reduce drag by 5–7%, saving airlines billions of litres of fuel per year.

The challenge

Wing tip vortices create induced drag that wastes significant fuel in commercial aviation, increasing costs and carbon emissions.

Nature's strategy

Eagles, vultures, and other large soaring birds

What was emulated

Primary feathers splay upward and outward at wing tips, creating multiple small surfaces that redirect and diffuse tip vortices.

The innovation

Winglet and raked wingtip designs inspired by the splayed primary feathers of soaring birds, which diffuse tip vortices and reduce induced drag.

Full case study

When a wing generates lift, it creates a pressure differential between its upper and lower surfaces. At the wing tip, high-pressure air spills around to the low-pressure side, creating a tip vortex — a swirling column of air that generates significant drag (called induced drag) and reduces efficiency. Birds that soar for hours — eagles, vultures, storks — have evolved an elegant solution: their primary feathers splay upward and outward at the wing tips, acting like multiple small winglets that redirect and diffuse tip vortices. This reduces induced drag while maintaining the high-lift, low-speed performance needed for soaring. Richard Whitcomb at NASA identified this principle in the 1970s and developed blended winglets for commercial aircraft. The Boeing 737-800 winglets reduce fuel consumption by 5-7%, saving approximately 200,000 litres per aircraft per year. Across the global commercial fleet, winglets save an estimated 2 billion litres of jet fuel annually — one of the highest-impact single engineering improvements in aviation history. The Boeing 787 takes this further with raked wingtips that more closely mimic the gradual feather-spread geometry of soaring birds. Advanced "split scimitar winglets" and variable-geometry wingtips continue to improve on the original biomimetic principle.