What do you mean, an African or European Swallow?

Estimating the Airspeed Velocity of an Unladen Swallow
Hashing out the classic question with Strouhal numbers and simplified flight waveforms.
by Jonathan Corum

After spending some time last month trying to develop alternate graphic presentations for kinematic ratios in winged flight, I decided to try to answer one of the timeless questions of science: just what is the airspeed velocity of an unladen swallow?

http://www.style.org/unladenswallow/