Originally Posted by
Ascend Charlie
Rotor thrust is acting from the hub, not the CG. When the T/R thrust tilts the fuselage left, the CG is no longer under the hub, and a restoring moment is created. The 2 moments are continually playing games with each other.
You clearly understand what is going on, but what you have written above could still be confusing. An accurate explanation must use the terminology correctly.
When introducing levers in elementary science, a physics teacher as I was, will only use moments about a fixed pivot/fulcrum. That is as far as Galileo went.
This makes the calculations easy to understand and completely hides the existence of the couples in equilibrium. If someone's education goes no further they will continue to think in those terms when faced with rotational effects and be forever looking for a pivot. That is not your situation, but it is that of many that have posted on this topic, including Nick Lappos.
A couple is a rotational effect, a vector, and its size is a moment. They are not the same thing once you advance from the simplifications of elementary science.
If you replace 'moment' with 'couple' above all is well, except that 'are continually playing games with each other' is not a decent substitute for 'are in equilibrium' or 'are in balance'.
I'm sorry to be picky, but these things matter to me.
