Sound when switching on external power
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@plhought said in Sound when switching on external power:
It's the anti-skid pump in the nose running to build up pressure. He has the switch set on all the time.
The breaker he pulls is for the Ground Idle Solenoids. CB is PROP GOV TEST. They are powered on the ground. Can get hot and melt their guts out.
Patrick
I can verify this behavior is simulated. Just tried it out over my lunch break. Nick really did do his homework on this.
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It's the anti-skid pump in the nose running to build up pressure. He has the switch set on all the time.
The breaker he pulls is for the Ground Idle Solenoids. CB is PROP GOV TEST. They are powered on the ground. Can get hot and melt their guts out.
Patrick
@plhought said in Sound when switching on external power:
The breaker he pulls is for the Ground Idle Solenoids. CB is PROP GOV TEST. They are powered on the ground. Can get hot and melt their guts out.
Patrick
Do you mind expanding on this a bit, what's happening that they necessitate being pulled and why?
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@plhought said in Sound when switching on external power:
The breaker he pulls is for the Ground Idle Solenoids. CB is PROP GOV TEST. They are powered on the ground. Can get hot and melt their guts out.
Patrick
Do you mind expanding on this a bit, what's happening that they necessitate being pulled and why?
The ground idle solenoids are on the "forward" propeller linkage if each engine. When energized, they draw the beta-arm "back" and set the propeller blade angle to a finer pitch.
The solenoids are energized any time the aircraft is on ground, and the left generator bus powered.
This is primarily for ground operations so the propeller speed is maintained out of the restricted range. A secondary effect is a finer pitch upon landing, and the flatter propeller pitch helps slow down the aircraft.
The solenoids do have a tendency to get very hot, and the plastic compound that covers the winding internally has a tendency of melting and the solenoid failing if left powered for an extended period of time on the ground. Hence why we pull the CB to de-energize the solenoids and try and save them.
Patrick
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The ground idle solenoids are on the "forward" propeller linkage if each engine. When energized, they draw the beta-arm "back" and set the propeller blade angle to a finer pitch.
The solenoids are energized any time the aircraft is on ground, and the left generator bus powered.
This is primarily for ground operations so the propeller speed is maintained out of the restricted range. A secondary effect is a finer pitch upon landing, and the flatter propeller pitch helps slow down the aircraft.
The solenoids do have a tendency to get very hot, and the plastic compound that covers the winding internally has a tendency of melting and the solenoid failing if left powered for an extended period of time on the ground. Hence why we pull the CB to de-energize the solenoids and try and save them.
Patrick
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@plhought interesting, thank you! And in practice, they would keep the prop RPM above the red range on the ground?
Sounds like Nick has another failure to add if he wants it.
Yeppers that's the idea.
Definitely a failure that could be added! At the moment though I know Nick is working on correctly modelling that function. At the moment they simply change the RPM display and don't really effect the engine.
My old job we kept a solenoid at all our bases precisely for this reason. Hot summer day and with a warm engine - It wasn't unusual for those solenoids to fail if the plane was left powered on waiting for pax or something for more than an hour.
I used to use a quick push of the low pitch test switch as a "first gear" to get the airplane moving without having to add any power. This would momentarily de-energize the solenoids on the ground, and resultant blade angle coarsening and Tq bump would get the airplane moving
. Helps keep the noise down on the ramp.Patrick
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Yeppers that's the idea.
Definitely a failure that could be added! At the moment though I know Nick is working on correctly modelling that function. At the moment they simply change the RPM display and don't really effect the engine.
My old job we kept a solenoid at all our bases precisely for this reason. Hot summer day and with a warm engine - It wasn't unusual for those solenoids to fail if the plane was left powered on waiting for pax or something for more than an hour.
I used to use a quick push of the low pitch test switch as a "first gear" to get the airplane moving without having to add any power. This would momentarily de-energize the solenoids on the ground, and resultant blade angle coarsening and Tq bump would get the airplane moving
. Helps keep the noise down on the ramp.Patrick
@plhought said in Sound when switching on external power:
Definitely a failure that could be added! At the moment though I know Nick is working on correctly modelling that function. At the moment they simply change the RPM display and don't really effect the engine.
I would like to add this failure, but it's pushing the MSFS propeller simulation towards being over-constrained in ways that I don't like. In other words, when I currently take control of the propeller simulation, it's for specific scenarios, like the govern tests or feathering, but this would be more of an "always on" thing, which can have unintended consequences.
Also, to clarify, my current governor simulation does affect the engine and propeller simulation, not just the RPM display. I don't know where you heard that, but it's not accurate.
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@plhought said in Sound when switching on external power:
Definitely a failure that could be added! At the moment though I know Nick is working on correctly modelling that function. At the moment they simply change the RPM display and don't really effect the engine.
I would like to add this failure, but it's pushing the MSFS propeller simulation towards being over-constrained in ways that I don't like. In other words, when I currently take control of the propeller simulation, it's for specific scenarios, like the govern tests or feathering, but this would be more of an "always on" thing, which can have unintended consequences.
Also, to clarify, my current governor simulation does affect the engine and propeller simulation, not just the RPM display. I don't know where you heard that, but it's not accurate.
I think we may be confusing the governor o/s test vs. the low pitch test.
When you use the low pitch test (releasing the solenoids) it is not a function of the prop governor - it's directly on the beta linkage. For example right now, you don't see a resultant increase in torque - and the RPM drop is only noticeable at flight idle. Whereas in the actual aircraft you'd see the resultant Tq increase and RPM drop until you added enough power to hit the propeller governing range (in most cases ~1700 RPM).
I'm pretty sure actually you had it at least pseudo-working correctly on the KA350.
EDIT: I can see the confusion though as the solenoids are powered from the PROP GOV TEST CB. Just a Beechism
Patrick
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It's less confusion (though I didn't know how the solenoids affected prop speed until a while ago), and more about how it has to be implemented. I don't get to program with such nuance, so everything that affects propeller RPM is a "governor" in my code.
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Honestly, you could probably "spoof it" in the gauge programming I suppose (I have no knowledge of actually coding these things though), and reality is 99% of people would probably be satisfied with it.
Unfortunately, only way to really model it correctly (as highlighted in an another thread) is to wholly develop a different engine model - and I don't think that's fair to put on you and this project at the moment. So is what it is.
You already got a Garrett you're going to have to somehow model in MSFS with the Turbo Commander so I think your hands are gonna be full haha.
Patrick
