The point of this article was to estimate the speed of a swallow knowing only the bird’s mass and wing length. As such it is an estimate, and further study is certainly needed. Read my original article for a discussion of bird flight where full kinematics (wingspan, mass, cruising speed, wingbeat frequency, and amplitude) are all known.
Actually I wrote the article under the assumption that the question was simply redundant. I agree that “airspeed” and “velocity” are synonyms, with each measuring distance per unit time. But asking “what is the velocity velocity” of an object is a problem, because it has been argued that no mass can move at velocity squared.
But I think I see where you're heading. If we assume for a moment that “what is the velocity squared?” is the correct question, then along with the mass of the bird we have everything needed to measure kinetic energy (KE=1/2mv2). In that case the bridgekeeper’s question could be interpreted as a roundabout way of trying to determine “what is the kinetic energy of an unladen swallow?” But then, I don’t think Leibniz published a description of kinetic energy until the 1680s, so it’s doubtful the bridgekeeper would have known about it centuries earlier.
Yes, amplitude is the distance from rest to crest or rest to trough. However my original article explains that I am following the convention set in the referenced Nature article, where amplitude is considered to be the same as wingtip excursion, the vertical distance traveled by the tip of the wing during the flapping stroke.
As I mentioned, no data other than body length was available for that species. If anyone has kinematic data for the African Swallow, please send it along.
Perhaps instead of saying “only two species are named after the continent,” I should have said “only two species have common names that reference regions or countries in Africa.”
Just when I thought I had Myanmar and Burma straight, the post-Mobuto Congo name change completely slipped my mind.
All illustrations were created by hand with Adobe Illustrator and Adobe Photoshop. All coding, including the CSS, was done by hand in BBEdit.
As has been previously reported, a five ounce bird could not carry a one pound coconut. In reality, the swallow is only about 0.5 oz, or 1/32 the weight of a one pound coconut. Even with the milk of the coconut drained, it would take a number of birds rigged to a good length of creeper to lift a coconut husk.
I am but one man, sir.
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