Biggest flying bird ever: How did it get off the ground?

... how did the giant take flight with such huge wings? Dr. Ksepka, a new curator of science at the Bruce Museum in Greenwich, Conn. developed a computer simulation to explain just that. The bird likely launched itself from the ground or ocean surface ...

http://www.csmonitor.com/Science/2014/0707/Biggest-flying-bird-ever-How-did-it-get-off-the-ground