Originally Posted by
autojohn
Maybe this is the whole story and the inherent droop is just determined by the speeder spring strength. (and non-linearity - fuzzy on this detail)
We're talking about the same topic just opposite ends of the spectrum. A couple more tidbits. Keep in mind this droop is nothing more than a "feature" of an analog-controlled governing system. In digitally-controlled governing systems droop is basically non-existent even on the same core engines. But from my understanding there are a few other items that determine the inherent droop other than spring strength in an analog system. There is also the possibility of positive "droop" which I've seen called "droop cancelling"(?).
Now in some other older droop designs they also added an "anticipator" or "bias" device that "anticipated" the droop and reduced its effect (value). While the "non-linear" side of your statement is at or beyond my skill set, I seem to recall this type of governing system had to be developed in some form of non-linear fashion in order to function throughout its control range due to the variables of the signal inputs/outputs. Its my understanding that a digital controlled governing system is more linear due to the fact the input/output signals can be processed almost instantaneously via the EECU or similar unit and acted upon.
Having been riding shotgun in a 206 when it had a high side governor failure in a difficult location you will appreciate what that GOV does. Lucky for me, the pilot had a light touch and we made it down without me having to change the engine that night. If I can get it to post, I'll put up a booklet put out by Bendix/Allied Signal on your GOV/FCU system for your reading pleasure. Good luck.