to pcpahari_IAF,
No problem, this is complex stuff, keep plugging away!
Basically, it is confusing to use the term "stability" to describe all three properties under discussion: 1)the transient droop and 2) the permanent droop and 3) the oscillation. I would suggest that for clarity in differentiating between the three properties we are discussing, let's use 'stability" in the classic sense, as only 3) the freedom from oscillation.
your question: do we imply stable RPM as that RPM tendency to settle at a lower figure as stable OR will it be the RPM returning to original figure. IN answer, I would say neither - as I would like to clarify, stability is the measure of making the engine/rotor response free of oscillations. In fact, permanent droop (where the rpm is allowed to reduce slightly) is used to make the response more stable (more free of oscillations).
"If the Static Droop is more, Rotor RPM Stability will be ______. (More/Less) more stable
If I could use an analogy for permanent droop, imagine a steel table upon which we drop a solid steel ball. The ball would bounce for a long time against the table, because the rigidity of the table returns to the ball all the energy that the ball gives to the table. The ball is almost unstable, and is quite a problem as it oscillates. Now cover the steel table with 1 cm of rubber. When dropped, the ball would dent the rubber, and quickly come to rest. At rest, the ball would be slightly lower than the surface of the rubber, due to the permanent droop of the weight of the ball. In effect, the surface "gives" a little bit, and in doing so, helps the ball find true dynamic stability.