Originally Posted by
flyboyfreye
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OVERSPEED
"Counterweighted Propeller using Pressure to Decrease Pitch (see Fig. 2)
The flyweight toes raise the pilot valve plunger, uncovering ports in the driver gear shaft that permit pressure oil to flow from the propeller pitch changing mechanism. This allows propeller counterweights to take the propeller blades towards a higher pitch. The load on the engine is increased and engine speed is reduced."
UNDERSPEED
Counterweighted Propeller using Pressure to Decrease Pitch (see Fig. 2)
The pilot valve plunger is forced down uncovering the ports in the drive gear shaft that allow pressure oil to flow to the pitch changing mechanism of the propeller. This overcomes the force of the propeller counterweights and decreases the pitch of the propeller blade.
This scenario would seem to match the system as described in the cirrus, but no where do I see anything about it being a "counterweighted prop".
Now those at least make a little more sense...only a little. Here I will show you what I mean with a black bold in this quote and then a requote of your original. For overspeed I did just bold/black and underspeed in bold/black/underline.
Original:
I guess I was under the impression that in the CIRRUS ( a constant speed system ), when you pushed the throttle forward or began a descent, this was an overspeed. According to Section 7 of the SR-20 manual, it says "moving the throttle lever forward causes the governor to meter less high pressure oil to the hub allowing centrifugal force to lower the pitch." To me, this says that in an overspeed, oil is flowing out of the hub and into the sump. And that "reducing the power causes the governor to meter more high pressure oil to the prop hub, forcing the blades to a higher pitch, lower RPM position." So it would seem that in an underspeed, oil is flowing to the hub.
You see in your original the reverse was happening with regards to blade pitch according to your quotes. That is what was confusing, though after reading your book quote...
just wow lol.
As for your counterweights I am unfamiliar with any propeller system using separate counterweights. However, I have heard the flyweights called counterweights in a prop governor system. The rest of what is quoted seems controversial, even contradicting itself, and what I would recommend is going and asking your mechanic for the type of prop governor used. If you can post up the brand/type of prop governor here than we can try and track down a manual and get to the bottom of this.