The nature of flight in
Quetzalcoatlus and other giant azhdarchids was poorly understood until serious biomechanical studies were conducted in the 21st century. One early (1984) experiment by
Paul MacCready used practical aerodynamics to test the flight of
Quetzalcoatlus. MacCready constructed a model flying machine or
ornithopter with a simple computer functioning as an
autopilot. The model successfully flew with a combination of soaring and wing flapping;
[17] however, the model was half scale based on a then-current weight estimate of around 80 kg (180 lb), far lower than more modern estimates of over 200 kg (440 lb).
[18] The method of flight in these pterosaurs depends largely on weight, which has been controversial, and widely differing masses have been favored by different scientists. Some researchers have suggested that these animals employed slow,
soaringflight, while others have concluded that their flight was fast and dynamic.
[4] In 2010, Donald Henderson argued that the mass of
Q. northropi had been underestimated, even the highest estimates, and that it was too massive to have achieved powered flight. He estimated it in his 2010 paper as 540 kg (1,190 lb). Henderson argued that it may have been
flightless.
[18]
Reconstructed skeleton
However, most other flight capability estimates have disagreed with Henderson's research, suggesting instead an animal superbly adapted to long-range, extended flight. In 2010, Mike Habib, a professor of biomechanics at Chatham University, and Mark Witton, a British paleontologist, undertook further investigation into the claims of flightlessness in large pterosaurs. After factoring wingspan, body weight, and aerodynamics, computer modelling led the two researchers to conclude that
Q. northropi was capable of flight up to 130 km/h (80 mph) for 7 to 10 days at altitudes of 4,600 m (15,000 ft). Habib further suggested a maximum flight range of 13,000–19,000 km (8,000–12,000 mi) for
Q. northropi.
[19] Henderson's work was also further criticized by Witton and Habib in another study, who pointed out that although Henderson used excellent mass estimations, they were based on outdated pterosaur models, which caused Henderson's mass estimations to be more than double what Habib used in his estimations, and that anatomical study of
Q. northropi and other large pterosaur forelimbs show a higher degree of robustness than would be expected if they were purely quadrupedal.
[6] This study proposed that large pterosaurs most likely utilized a short burst of powered flight in order to then transition to thermal soaring.
