Monday, July 12, 2010

The Airspeed of an Unladen Swallow in Flight

"WHAT ... is the airspeed of a laden swallow in flight?"
One of the classic questions of science popular culture Monty Python fans, but before weighing down a 20 gram bird with the fruit of a Cocos nucifera, someone really ought to look into how they fly normally.

And of course, someone has.

"In order to maintain airspeed velocity, a swallow needs to beat its wings forty-three times every second, right?"

Actually, wrong. By comparing the European Swallow with bird species of similar body mass, we can estimate that the swallow beats its wings 18 times a second with an amplitude of 18 cm:

SpeciesBody massFrequencyAmplitude
Zebra Finch13 g27 Hz11 cm
European Swallow20 g≈ 18 Hz?≈ 18 cm?
Downy Woodpecker27 g14 Hz29 cm
Budgerigar34 g14 Hz15 cm

Check out the full article at

Or ... you could go with the original research!

Now that I think about it, I must have posted this once before. But what the heck, it's worth repeating. :-)
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