Avian Expert Articles

Physics of Bird Flight Inspire Scientists

close up of Pacific parrotlet wearing goggles
Photo credit: Eric Gutierrez

Science has made life a different experience for many in the world. That includes the many creatures within its helpful sphere that have benefited from advancements that have significantly improved their lives. From the physical aspects of those science-led advancements like 3D printing of beaks, feet, and shells, to the dedicated study of specialized areas like preservation improvement. It also assists in the developing understanding of species and how they experience their world, thus bettering the lives of our beautiful creatures.

Some areas that are gaining footholds are the study of how birds think, and how they do the physical things they do. One of those is the physics of flying. Currently, there are but a few theories on how birds fly. Essentially, we assume that birds fly with the same physics planes do. The prevailing forces involve abilities to lift and to sustain guided flight though the air.

Theoretically, it is assumed that birds create wingtip vortices, much like airplanes do. What this means is that a created circular spin of air that leaves the area of the wings create a ‘vortex drag’, thus making it difficult for birds to fly effortlessly, as it seems they do from our vantage point. However, ‘vortex drag’ is important when it is necessary to slow down and land without injury or incident. Nevertheless, with all of our assumptions of flight, it was time for a team of scientists at Stanford University to look into the world of bird flight and see just how close our understanding was to the reality of bird flight. What they discovered surprised them.

Parrotlet Obi Put To The Test

For these series of tests, the team trained a Pacific parrotlet, who was named Obi — as in Obi-Wan Kenobi — to fly through a small study field. To create this useable test platform, the team placed two perches approximately three feet apart from each other. Between those perches were the tools used to determine lift and thrust and to actually view the physics that create flight. The tools used were twelve strategically placed cameras, and a laser sheet to map the flight pattern and air disturbances created by the wings of Obi. In order to acquire the visual of the disturbed air, a mist of extremely fine water particles was sprayed between the two perches. Obi’s simple job was to fly between the two perches. The laser flashed brilliantly at the rate of 1,000 times per second while the cameras captured Obi’s flight between perches at the astonishing rate of 1,000 photo captures per second.

Pacific parrotlet wearing goggles
Photo by Eric Gutierrez

To protect Obi’s eyes from the fast flashing laser making up the scanning field through which he flew, a custom-designed, 3D-printed pair of goggles was fitted to the bird’s head. The lenses used in the goggles are the same used by the scientists in the study.

What the team soon discovered was that the vortices created by the bird’s flight rapidly dissipated almost as soon as they were created. The assumption was that the circling air patterns (lightly explained above) would sustain for a time. Because of this discovery, the usual assumptions of lift and sustained flight were greatly challenged. During the ongoing course of the study, different tests were implemented to check on the validity of the standard models of lift and flight. All of the tests showed different results that didn’t conform to the standard theories.

The recorded streams of data will help engineers in several areas of flight including our understanding of how birds attain flight and sustain it. Other beneficiaries of the study include the perfection of robotic wings in order to create better precision for flight. As a direct result of the surprising findings generated by Obi and his tests, further studies will be finely tuned to better understand bird flight and to narrow the safer and more effective realities of flight for our own use.

The complex and finely detailed results of the study were made public in the scientific journal, Bioinspiration and Biomimetics on December 6 of 2016. It can be perused at your leisure at this link that leads to the IOPSCIENCE website. From within the article, you can download a 16-page PDF of the complete writ.

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