Coriolis vs Conservation of Angular momentum

[Vessbot]

Originally Posted by Ascend Charlie

You're arguing in circles mate.

You're arguing that a phenomenon (max displacement approx. 90 degrees after the force) happens because of a thing (s+ut + 1/2 a t ^2), but I'm pointing out that the same phenomenon happens without that thing. If it happens without the thing, the thing can't really be the reason can it?

I gave you an example that boils away every possible confounding factor and leaves the simplest possible arrangement that shows the behavior of rotating matter, with perfect 90 degree phase lag but with no s+ut + 1/2 a t ^2, so maybe you should give a twopenny about it.

Originally Posted by ApolloHeli

They are not. Phase lag is "around 90°" but not exactly, and varies for every helicopter. The exact angle has to do with the relationship between the resonance of the flapping behaviour of the blades compared to the rpm of the rotor system as a whole. Offset flapping hinges (or apparent offset 'hinges' such as in rigid rotor systems) increase the flapping resonance so that it is slightly higher than 1/revolution meaning that for an applied force, the peak of the flapping oscillation will occur slightly less than 90° later.

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I was wrong to call them "the same thing," but how about the chief "ingredient" (to use heliman500's word, even though he says it's a small ingredient). Yes, all manner of complicated hinge arrangements and various forces modify the phase lag, but why is the base value that is modified, the same as what a simple rotating body (gyroscope) does?

All the complications happen near the center, leaving most of the motion dominated by simple rotation. (Now if the offset of the flapping hinge was something like at 90% of the radius, it would be a different story.) When a basic motion is modified by higher order effects to add up to the final result, it doesn't disappear and is still there underneath. And in this case, enough of it is there to be not only clearly recognizable, but the main driver of the motion.

For a clear-cut example (I mean a general example of superposed motions and the contributions of their causes, not a specific example of gyroscopic motion), look at the Earth's rotation. Measured to the accuracy available to today's instruments, it has its own precession, nutation, and God knows what else, and they're not even constant. They're affected by tectonic movement, ocean currents, celestial bodies, and other things, which change the rotation rate as well. Leap seconds have to be added at irregular intervals to account for this. Looking at all this, you wouldn't say that the Earth is not a rotating ball, and you have to calculate all these mind-boggling stacked motions every time you describe the Earth's movements. No, the simple rotation is still there underneath, dominating the total motion, so a constant-rate spinning ball is still a correct first-order approximation that serves just fine as a model. (And ultimately everything we talk about is models, unless you endeavor to calculate the individual movement of all the atoms of the messy system, every time you talk about anything.)