An Indian American professor, a graduate of Kolkata's premier Jadavpur University, has recreated the flight plan of an enormous bird that dominated the skies above the Argentine grassy pampas about six million years ago.
Using software originally written for helicopters, Sankar Chatterjee and two colleagues of the Museum of Texas Tech University, Lubbock, analysed the aerodynamic secrets of the giant Argentavis bird to reveal how it took off, remained aloft and then landed.
With a seven-metre wingspan the giant bird was the size of a Cessna 152 aircraft, had a formidable 20-inch skull and eagle-like beak. The bird was a member of the extinct bird family Teratornithidae, a predatory group of birds related to storks and vultures, the Telegraph reported.
As the world's largest known flying bird, the aerodynamics of Argentavis has been a subject of speculation for more than two decades.
"It seems Argentavis was a lazy glider that relied either on updrafts in the rocky Andes or thermals on the grassy pampas, to provide sufficient lifting power," the Kolkata-born professor said.
Working with Jack Templin and Kenneth Campbell, Prof Chatterjee estimated the power available from the bird's pectoral muscles and concluded the Argentavis would have been incapable of flight powered entirely by wing flapping, or even of a standing takeoff, because it lacked sufficient muscle power.
However, it was an economical high-performance glider with a turning radius of 100 feet, short enough for it to circle around as it searched the plains of the Angentinian pampas for prey.
The team concluded that the giant bird probably used some of the techniques used by today's hang-glider pilots such as running on sloping ground to get thrust or energy, or running with a headwind behind it.
"Think about a super-sized bald eagle with a 21-foot wingspan," Chatterjee said. "It would darken the sky. It's almost like a tale from the Arabian Nights. It was a very aggressive bird that flew over the pampas of Argentina to sweep down from the sky and seize large prey with a formidable beak."
Prof Chatterjee graduated from Jadavpur University in 1962. He was also a Fellow of London University.