Perhaps my mention of Newton's third law gave you the impression that I was advocating for that "stone skip" theory — I assure you I wasn't! Especially as presented on that page, it is obviously junk (:
But surely you agree, broadly, that if birds are flying inside a sealed box, the box still weighs the same amount as if they were standing, right? (modulo some fluctuations)
All of the pressure differentials and whatnot have the net effect that an upward force on the wing results in a downward force elsewhere. The purpose of the scale is to measure that force — like measuring the weight of the box with birds in it.
In the hovering helicopter example, wouldn't you agree that a (large) scale directly under the helicopter will measure a weight corresponding to the helicopter's lift force? Like if I blow directly onto a kitchen scale — it will measure some grams.
Perhaps my mention of Newton's third law gave you the impression that I was advocating for that "stone skip" theory — I assure you I wasn't! Especially as presented on that page, it is obviously junk (:
But surely you agree, broadly, that if birds are flying inside a sealed box, the box still weighs the same amount as if they were standing, right? (modulo some fluctuations)
All of the pressure differentials and whatnot have the net effect that an upward force on the wing results in a downward force elsewhere. The purpose of the scale is to measure that force — like measuring the weight of the box with birds in it.
In the hovering helicopter example, wouldn't you agree that a (large) scale directly under the helicopter will measure a weight corresponding to the helicopter's lift force? Like if I blow directly onto a kitchen scale — it will measure some grams.
Edit: I feel we are kinda re-hashing the Bernoulli/Newton discussion also addressed at the nasa site: https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/a... — 'So both "Bernoulli" and "Newton" are correct ...'
For reference, the correct Newtonian explanation (flow turning) is also covered: https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/a...