Professor Jing-Tang Yang’s research results of the study on bird’s eye view have been published in Nature Physics with the column article specially covered by their senior editor, Andreas Trabesinger, and entitled “Bird’s Eye View” last August (Vol. 7, news and Views, pp. 595, DOI: 10.1038/nphys2064). Also the same year back in 2011, Professor Yang’s outstanding research was also published in Physics Buzz and Science News by the journalists from Science and the website of APS (American Physical Society) as the monthly topic.
The aerodynamic mechanism of the smaller bird’s eye view was first published in Physical Review E (DOI:10.1103/PhysRevE.84.012901) in 2011, presenting Professor Jing-Tang Yang’s great research results with his research teamwork. Their research results suggest that smaller birds impress with their capabilities: hummingbirds, famously, manage to fly backwards and sideways. And there are other smaller birds that have also mastered hovering flight, with their bodies seemingly suspended in mid air as they rapidly flap their wings. Professor Jinag-Tang Yang’s research team have now uncovered a phenomenon that makes the feat seem even more remarkable, at least from a mechanics point of view: the most stable point of the bird’s motion while hovering is not at its center of gravity but at eye level. To work out how hovering birds might manage to stabilize their position such that their eyes at the center of motion, their research team studied a passerine known as the Japanese White-eye. They trained birds to perform their hovering flight inside a chamber monitored by high-speed cameras, each recording 1000 frames per second, which is fast enough to finely resolve the flapping motion at some 24 Hz. The recordings reveal that the bird’s body swings up and down quite substantially during hovering.
According to this journal article, the research team (Jian-Yuan Su and colleagues) from NTU Department of Mechanical Engineering led by Professor Jing-Tang Yang has already successfully found that how hovering birds might manage to stabilize their position such that their eyes are at the center of motion, studied a passerine known as the Japanese White-eye. The point of action of the lifting force does not, however, coincide with the center of mass of the passerine; instead, its position is slightly dorsal. They discovered the fact by using aerodynamic mechanism through experiments. The Japanese White-eye swings up and down during hovering, and during downstroke, the extends wings generate a downward air jet that pushes the bird up, whereas the wings are retracted, is aerodynamically inactive; therefore the bird drops under gravity to its original position. As we as using the aerodynamic mechanisms proposed by Professor Jing-Tang Yang’s research team, the bird can further stabilize its head and eyes by muscular and skeletal motion. This should enable it not only to keep a level head, but also to maintain its gaze and keep its eyes on the prize. There are more to be learned and imitated from the other creatures: understanding this aerodynamic mechanism of the smaller bird’s eye view will definitely help a lot applying to the innovative micro aerial vehicles in the near future for a development of a great breakthrough controlling the vehicles.