Jets, drones could become highly maneuverable using design, flight lessons from hawks

A study in the United States analyzed flight patterns of birds, and it could help make new designs of flying objects, such as jets or drones.

Researchers from the University of Oxford and the University of California, Davis, used a combination of motion capture and wind tunnel modeling to see how a Harris鈥檚 hawk changes its wing and tail shape as it flies through a narrow gap. 

The team set up a 3D printed model of a hawk wing for testing in the UC Davis wind tunnel. Based on motion capture imaging at Oxford University, the wind model shows how a Harris鈥檚 hawk changes aerodynamic stability as it flies through a gap. The team claimed that the study of this type can give insight into aerodynamics that could be applied to uncrewed aerial vehicles.

The team found that when the hawk tucks its wings, it shifts from an unstable to a stable state. In aerodynamics, being makes a flying object highly maneuverable, like a jet fighter, while being stable means it can maintain a steady course. 

Motion capture imaging

The researchers used motion capture imaging at Oxford鈥檚 flight hall to film a Harris鈥檚 hawk gliding from one perch to another. They placed a pair of soft poles in the flight path to create a narrow gap, encouraging the bird to tuck its wings as it flew through, a press release. 

After analyzing the video, they constructed models of the hawk鈥檚 wing and tail at different points in the maneuver and tested them in the wind tunnel facility at the UC Davis College of Engineering. Models were made from resin 3D printing thanks to support from the UC Davis Engineering Student Design Center, as per the .

Progression of wing and tail configurations

Published in Journal of the Royal Society Interface, the analyzed the progression of wing and tail configurations of a free-gliding Harris鈥檚 hawk (Parabuteo unicinctus) during a wing-tucking manoeuvre.

鈥淲ind tunnel experiments on three-dimensional-printed models revealed that tucked configurations were statically stable, while spread configurations displayed a nonlinear relationship between pitching moment and lift,鈥 said researchers in the study.

鈥淭his nonlinearity allows configurations to be either stable or unstable depending on the lift state, affording a previously under-explored source of flight performance flexibility.鈥

Birds control their flight differently from traditional aircraft

The team revealed that Harris鈥檚 hawks hunt as a team, often flushing out prey and flying around trees and cacti. Like most birds, they can rapidly shift from gliding flight to tucking in their wings to avoid obstacles.

The findings of the study suggest that birds control their flight differently than traditional aircraft, as human-built aircraft usually do not shift between stable and unstable states in this way.

鈥淲e found that the hawk transitioned from an unstable, spread configuration to a stable, tucked configuration as it traversed the gap, shifting the effective static margin from 鈭25% to 19% of the reference chord,鈥 said researchers in the study.

This outcome will advance novel bio-inspired, fixed-wing uncrewed aerial vehicle designs capable of rapid transitions, according to the study.