Red Queens and Hummingbirds

Red Queens, hummingbirds, and helicopters have to run as fast as they can simply to stay in one place. Actually going somewhere is usually easier. This circumstance is the result of the interaction of "induced" drag (the drag or retarding force intrinsic to the generation of lift) and parasitic drag (the drag produced by friction of the air). The former scales like 1/(wing velocity) squared and the latter inversely (velocity squared), which means that induced drag dominates at low velocities and parasitic drag at high velocities.

Another fun fact from Henk Tennekes Simple Science of Flight.

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