Aerodynamic Characteristics of the Crest with Membrane Attachment on Cretaceous Pterodactyloid Nyctosaurus  

作　　者：XING Lida WU Jianghao LU Yi Lü Junchang JI Qiang 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [2]School of Transportation Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China

出　　处：《Acta Geologica Sinica(English Edition)》2009年第1期25-32,共8页地质学报（英文版）

基　　金：supported by the Chinese Ministry of Science and Technology (973 Project,2006CB701405);China Geological Survey,National Geographic (China Edition)and China Aviation Media Group.

摘　　要：The Nyctosaurus specimen K J1 was reconstructed under the hypothesis that there is a membrane attached to the crest; the so-called headsail crest. The aerodynamic forces and moment acting on the headsail crest were analyzed. It was shown that K J1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust （one of the aerodynamic forces, used to overcome body drag in forward flight） and that the magnitude of the thrust and moment could vary with the gesture angle and the relative location between the aerodynamic center of the headsail crest and body＇s center of gravity. Three scenarios were tested for comparison： the crest with membrane attachment, the crest without membrane attachment and the absence of a cranial crest. It was shown that the aerodynamic characteristics （increasing, maintaining and decreasing thrusts and moment） would have almost disappear in flight for the crest without membrane attachment and was non-existent without the cranial crest. It is suggested from aerodynamics evidence alone that Nyctosaurus specimen KJ1 had a membrane attached to the crest and used this reconstructed form for auxiliary flight control.The Nyctosaurus specimen K J1 was reconstructed under the hypothesis that there is a membrane attached to the crest; the so-called headsail crest. The aerodynamic forces and moment acting on the headsail crest were analyzed. It was shown that K J1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust （one of the aerodynamic forces, used to overcome body drag in forward flight） and that the magnitude of the thrust and moment could vary with the gesture angle and the relative location between the aerodynamic center of the headsail crest and body＇s center of gravity. Three scenarios were tested for comparison： the crest with membrane attachment, the crest without membrane attachment and the absence of a cranial crest. It was shown that the aerodynamic characteristics （increasing, maintaining and decreasing thrusts and moment） would have almost disappear in flight for the crest without membrane attachment and was non-existent without the cranial crest. It is suggested from aerodynamics evidence alone that Nyctosaurus specimen KJ1 had a membrane attached to the crest and used this reconstructed form for auxiliary flight control.

关 键 词：aerodynamic forces and moment flight dynamic Nyctosaurus headsail crest 

分 类 号：V22[航空宇航科学与技术—飞行器设计]