ESPCI web site
Aerodynamic Efficiency in Small and Large Aircraft
The aerodynamic efficiency of an aircraft is conventionally measured by the dimensionless lift to drag ratio, L/D, and higher values are almost always better. The design or evolution of flying devices involves a lot more than this single measure, but it is still interesting to enquire how close any given device might be to some reachable optimal solution, or even just a better one. Two sets of such enquiries will be outlined, one involving scales where birds, bats and micro-air vehicles intersect in design space, and one where we will claim that most commercial transports are operating far from likely superior solutions. Tracks for future research on these points also overlap in interesting ways.