Physiology of Flight

Abstract

The foregoing has presented the theoretical grounds for estimating the energetics of flight. These theoretical methods predict the mechanical power required to fly, that is, the power output, which also is treated for different flight modes in Chapters 8 and 9. A large part of the metabolic rate appears as heat production in the body. The actual, metabolic, energy cost of flight (chemical power output) depends on the mechanical power requirement (chemical power input) and the mechanical efficiency of the muscles (power output/power input) in converting chemical, metabolic, energy into mechanical work. The power input can be measured by various methods, but, like the theoretical approaches, each method has its advantages and disadvantages. Energy expenditure during flight, therefore, can best be understood when several, theoretical and experimental, approaches are used concurrently.