The physics of flight: II. Flapping wings

Abstract

In any conventional aircraft the wings provide the lift and the engines provide the thrust.In a bird, however, the wings have to provide the thrust as well as the lift. In this article weshall use the ideas presented in the first article of this series to develop a simple theory toexplain how this comes about, and use it to predict some important characteristics of theflight of birds, including their wingbeat patterns and their minimum power requirements.