中間省去，劃重點。
https://archaeology.uiowa.edu/american-indian-archery-technology-0
merican Indian Archery Technology
Series in Ancient Technologies
Fletching of bird feathers was sewn to or inserted in the shaft. Feathers of wild turkey were preferred but many other birds, including eagle, crow, goose, hawk, and turkey, were often used. Sinew was generally used to attach the fletching by first stripping some of the feathers from the front and back of the vane and then tying the vane to the shaft in front of and behind the remaining feathers. Sometimes plant twine was used to sew through the quill. Hide glue was used with or instead of sinew ties. Animal products like sinew have the advantage of tightening as they dry.
The fletching balances the weight of the arrowhead to prevent the arrow from tumbling end-over-end in flight. When fletched properly, an arrow may spin in flight producing an ideal trajectory. A similar effectiveness is gained by placing grooves in the barrel of a rifle to cause the bullet to spin. In fact, until the invention of rifled guns, bows generally proved to be more accurate and could shoot arrows further than powder-thrown missiles 。。。。。。。。。。。。。。。
