Raptor wing morphing with flight speed |
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Authors: | Jorn A Cheney Jonathan P J Stevenson Nicholas E Durston Masateru Maeda Jialei Song David A Megson-Smith Shane P Windsor James R Usherwood Richard J Bomphrey |
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Affiliation: | 1.Structure and Motional Laboratory, Royal Veterinary College, Hatfield AL9 7TA, UK;2.Department of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UK;3.School of Mechanical Engineering, Dongguan University of Technology, Guangdong, People''s Republic of China;4.Interface Analysis Centre, School of Physics, University of Bristol, Bristol BS8 1TL, UK |
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Abstract: | In gliding flight, birds morph their wings and tails to control their flight trajectory and speed. Using high-resolution videogrammetry, we reconstructed accurate and detailed three-dimensional geometries of gliding flights for three raptors (barn owl, Tyto alba; tawny owl, Strix aluco, and goshawk, Accipiter gentilis). Wing shapes were highly repeatable and shoulder actuation was a key component of reconfiguring the overall planform and controlling angle of attack. The three birds shared common spanwise patterns of wing twist, an inverse relationship between twist and peak camber, and held their wings depressed below their shoulder in an anhedral configuration. With increased speed, all three birds tended to reduce camber throughout the wing, and their wings bent in a saddle-shape pattern. A number of morphing features suggest that the coordinated movements of the wing and tail support efficient flight, and that the tail may act to modulate wing camber through indirect aeroelastic control. |
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Keywords: | wing morphing bird wings three-dimensional reconstruction bird aerodynamics |
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