Feathers as aerofoils Rachis: tapering central support of a feather: to either side is the vane.
{"Image DocumentName": "Feathers as aerofoilsRachis: tapering central support of a feather: to either side is the vane.", "Image ImageDescription": "Body feathers have vanes symmetrical about the rachis but bird primaries are not symmetrical in this way: in primaries the rachis is closer to the edge that leads in flight. In strong fliers the leading vane is sometimes almost obliterated. This asymmetry gives each feather an aerofoil transverse section, i.e., the primaries of most birds function as aerofoils in their own right. Feduccia, A. & Tordoff, H.B Feathers of Archaeopteryx: asymmetric vanes indicate aerodynamic function. Science 203:", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}