Strange prop and engine gauge behavior
Posted: Sat Jul 07, 2018 9:24 pm
I'm experiencing some odd propeller behavior as well as some suspect indications on the gauges.
The main issue is the prop kind of has a mind of its own. Trying to set climb power the rpm would consistently jump back up about 75 rpm a few moments after I pulled it back. For example, I pulled it back to 2000 only to have it rise back up to about 2070 a second later. The next time it rose back up to around 2050. It took me a while to finally get it to settle on 2000 rpm. During descent it began acting up again in response to my power changes. Unless I am completely mistaken, I believe the prop rpm should more or less stay right around where it is set on a PT6 (or just about any turboprop for that matter) unless there are dramatic power changes or extremely low power settings, in both cases the governor would have troubles maintaining the rpm set. I can assure you that this is not a control calibration issue.
Other oddities I found was what I thought to be a lack of expected torque rise when decreasing prop rpm at a given power setting. This may be model specific and just how this particular aircraft is but it was something I thought peculiar. Far more peculiar, however, was the behavior of the small needle on the %Ng gauge. It seemed to have no correlation to the main needle what so ever (it should be indicating the same thing, just down to a single percent). It often would give completely erroneous readings. For example, it would point to 2 when the large needle was indicating roughly 86%. Stranger still is that it would move in the opposite direction from what it should have. Making a small power decrease of just a few percent the needle actually spun in the wrong direction indicating an increase!
I uninstalled and reinstalled the aircraft to no avail. UAC set, ran as admin and AV turned off so that's not it. The problem persisted exactly as before.
I love everything else about this plane so I'm not trying to lambaste it or anything. I love the start up/shut down simulation, the sounds and everything else. ITT seems to be very well modeled too indicating appropriate rises in temps as you climb and so on- well done there! I just can't figure what's going on with the prop setting and other engine indications during the rest of my flight.
The main issue is the prop kind of has a mind of its own. Trying to set climb power the rpm would consistently jump back up about 75 rpm a few moments after I pulled it back. For example, I pulled it back to 2000 only to have it rise back up to about 2070 a second later. The next time it rose back up to around 2050. It took me a while to finally get it to settle on 2000 rpm. During descent it began acting up again in response to my power changes. Unless I am completely mistaken, I believe the prop rpm should more or less stay right around where it is set on a PT6 (or just about any turboprop for that matter) unless there are dramatic power changes or extremely low power settings, in both cases the governor would have troubles maintaining the rpm set. I can assure you that this is not a control calibration issue.
Other oddities I found was what I thought to be a lack of expected torque rise when decreasing prop rpm at a given power setting. This may be model specific and just how this particular aircraft is but it was something I thought peculiar. Far more peculiar, however, was the behavior of the small needle on the %Ng gauge. It seemed to have no correlation to the main needle what so ever (it should be indicating the same thing, just down to a single percent). It often would give completely erroneous readings. For example, it would point to 2 when the large needle was indicating roughly 86%. Stranger still is that it would move in the opposite direction from what it should have. Making a small power decrease of just a few percent the needle actually spun in the wrong direction indicating an increase!
I uninstalled and reinstalled the aircraft to no avail. UAC set, ran as admin and AV turned off so that's not it. The problem persisted exactly as before.
I love everything else about this plane so I'm not trying to lambaste it or anything. I love the start up/shut down simulation, the sounds and everything else. ITT seems to be very well modeled too indicating appropriate rises in temps as you climb and so on- well done there! I just can't figure what's going on with the prop setting and other engine indications during the rest of my flight.