Alright after a couple of years, I'm finally dedicating some time to learning the Constant Speed Propeller (CSP) operations. I've kinda veered away from these as they truly did confuse me, so I mainly stuck with fixed props (such as on the Cessna 152/172) or jet engines.
That one extra knob throws me for a loop, although after a bit of reading, and soon to be experimentation, I'm planning on mastering that blue knob.
In general it seems, that blue knob does nothing more than set a governor to maintain a certain speed of the propeller(s). This came about because for instance, if you dove in a fixed prop plane, without adjusting the throttle, the prop would exceed rpms limits if you weren't careful, due to the increased air speed across the prop. But, in the case of a CSP, the governor will adjust the pitch of a propeller to maintain it's set rpm. Am I good so far?
Now according to my previous lack of knowledge, one would think that the black (throttle) lever would control rpm in a CSP plane. More throttle equals more fuel right? This can be the case, should the prop hit either mechanical stop. But in this case if we are within the stops, the black lever does nothing more than control how hard (or easy) it is for the engine to suck air into the intake. If we pull the black lever back, we restrict air flow, and so the engine has to work that much harder to pull air into the engine. To maintain the set RPM, the pitch will adjust accordingly (i'm assuming to a lower pitch), to lighten the load on the engine, to allow it to keep spinning at set rpm. Am I completely off base with this? The inverse is true, if you open up the throttle all the way, the engine will be drowning in air, and the pitch will adjust to a higher setting to induce more load on the engine.
Manifold pressure was also a tiddly bit confusing as well. If you opened the throttle to 100%, with the engine not running, you MP should be reading whatever barometric pressure is. So if barometric pressure is 29.92 for instance, MP should read just short of 30". With the engine not running, and you close the throttle, it should also be reading 30", due to the throttle not actually creating an airtight seal. Now lets say we start the engine and put it at idle, and completely close the throttle. That little bit of airflow past the throttle valve will be enough to keep the engine running, but your MP should drop substantially. This is due to more of a vacuum in the suction chamber.
Before I go on to pollute anymore people's idea of CSP's, I'll stop here for peer review. Am I on track so far, or should I do some more studying.