Originally Posted by
maxtork
1-Black magic causes the rotor system to react 90 degrees out of phase from the control input (generally speaking, see below). On a 2 bladed teetering system this seems to be the case anyways.
Fixed that for you....
Originally Posted by
Ascend Charlie
The books use "precession" as a way of getting stupid students to sort-of understand why the disc behaves the way it does.
I think we have the basics of the issue summarised here, with apologies to the students. There is a lot at work in and around a rotor disc with mechanics and aerodynamics fighting each other on one end and cooperating on the other. In itself, the principle that we call gyroscopic precession is a simplification of the dynamics of a rotating system of masses, but we needed to boil it down to something comprehensible. I still think that it is safe to say that the properties of gyroscopes have a place within the various influences on a rotor system, but what that place is and how it interacts with the rest is something I will happily leave to others to explain.
A lot of our understanding of things like this are based on simplifications, but we then tend to run into the limitations of those simplifications when something doesn't fit into this mould anymore. That doesn't mean that the principle is wrong. We can get into a lovely discussion on how Bernoulli does not fully explain how a wing produces lift and drag. It does not mean that Bernoulli got it wrong. It means that we've got an opportunity to learn.