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MSFS CJ4 - N1% Throttle Position / Amount

M

MarkRWatney

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unitedstates
Currently, I am using the "GENERAL ENG THROTTLE LEVER POSITION:1" variable to get the amount of throttle being used in the CJ4 but the SimConnect values are different than what is displayed in the cockpit.

The CJ4 is showing 77.1 in the cockpit (Working-Title-Mod) and the value I am getting from SimConnect is 64.1.

Either I am using the incorrect variable or I need to apply some math against the returned value? The Unit value in the help text for that field is "Percent". I am stumped. I am getting an Engine Type of "1".

I do see the variable "GENERAL ENG THROTTLE MANAGED MODE" too and I queried that and it came back with 0. But I do not think the CJ4 uses managed mode, but I am not sure about that.

Thanks for your help!
 
M

MarkRWatney

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unitedstates
I missed that the SimVarWatcher, "SimVarTokens" has the unit value of "percent scaler 16k" for the "GENERAL ENG THROTTLE LEVER POSITION:1" variable.

So, after Googling for "percent scaler 16k" I come up with nothing on that topic. Doing simple math against the return value, between what is displayed in the cockpit and the SimConnect return value does not work against the whole scale of the throttle from 0 to 100%. At 100% throttle that variable is returning a value that is basically 16,000. But at a value of 8,000 (half) from the return value, it shows 64.8 on the cockpit display...

Could this be a Working-Title-Mod issue that they are displaying an incorrect value? I doubt it! It is Junior-Boi here, doing something wrong.

Here is a picture of what I am talking about if that helps. Notice the 8K return value of 16K scaler, but a 64.8% value shown in the cockpit.

(Ignore the "percent" unit value on the left. That is my first attempt at getting the correct percentage.)
CJ4.png
 
M

MarkRWatney

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Thanks for that tidbit, ZenMusic. I didn't see anywhere on the net that 16K scaler represents 16383. I will remember that in/for the future.

But, you helped me to look outside of the forest... Those Dang Trees!

The number I am looking for is: "TURB ENG CORRECTED N1:1".

That SimVar is reporting back the correct percentage that matches the CJ4 dead-on.

I have the value I have been searching for. Thanks for your help, Mate!
 
WarpD

WarpD

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Uh... I do not believe the PL21 displays corrected N1/N2. Also... throttle position percentage does not equal N1 value. Not sure why you think it should.
 
M

MarkRWatney

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unitedstates
I figured out the throttle position percentage is not the same thing as N1. Thanks. I am totally new to this airplane stuff.

I did just make a flight in the CJ4 and using the CORRECTED value seems to match the displayed percentage. Are you thinking it is the "TURB ENG COMMANDED N1" variable instead?
 
M

MarkRWatney

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unitedstates
I just double-checked it.

Using the "TURB ENG CORRECTED N1:1" matches the output on the dash of the CJ4. The "TURB ENG COMMANDED N1" version is about 1.5 percent less.
 
ZenMusic

ZenMusic

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MarkRWatney said:
I just double-checked it.

Using the "TURB ENG CORRECTED N1:1" matches the output on the dash of the CJ4. The "TURB ENG COMMANDED N1" version is about 1.5 percent less.
Click to expand...
GENERAL ENG THROTTLE LEVER POSITION:1 , percent gives me accurate throttle position :)2 for engine 2 etc.)
 
WarpD

WarpD

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us-ohio
MarkRWatney said:
"TURB ENG COMMANDED N1"
Click to expand...
There is no such variable.

There is corrected N1 and uncorrected N1. If the PL21 in the CJ4 is displaying corrected N1... it is incorrect. The real aircraft does not display corrected N1/N2 values, it displays uncorrected N1/N2 values.
 
M

MarkRWatney

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unitedstates
My bad, sorry Warp. I was starting to see variables all over the place last night.

hr = SimConnect_AddToDataDefinition(hSimConnect, DEFINITION_ID_AP, "TURB ENG CORRECTED N1:1", "percentage"); // N1 POSITION

I'm not sure about the CJ4 using corrected or uncorrected, IRL or the MSFS default CJ4. The Working-Title plane matches using the code I have above. I will try the uncorrected value to see if it returns the same result in the Working-Title variant.

Thanks for correcting me!
 
WarpD

WarpD

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2,077
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us-ohio
If they have the PL21 using the corrected values, that would be odd. I don't recall any of the Citation business jets displaying corrected N-values.
 
M

MarkRWatney

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unitedstates
Possible tomorrow I can revisit this in the CJ4. I will compare what values both SimVars return in relation to what the dashboard has to say. That will give us a conclusive answer. :)
 
M

MarkRWatney

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As I suspected. It looks like the Working Title CJ4 is using the Corrected N1 variable. In the last image (70% Throttle setting) there is a slight rounding difference going on between the two numbers.

I am using the correct variables - right? Or is there something else that I should use?

Throttle 0.jpg


Throttle 40.jpg


Throttle 70.jpg
 
M

MarkRWatney

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unitedstates
I have sent a PM in the MSFS forum to the pilot who has worked with their project. Hopefully, they will take a look at it and let us know what the issue is on that.

Thanks, Warp!
 
Roy Holmes

Roy Holmes

Resource contributor
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1,803
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Mark,
If you want to understand what corrected means in the context of engine performance go have a trawl in the Aircraft Design Flight dynamics forum or download "FS Thrust vs Altitude calculations" from page 11 of the Resources part of this website. I have a nasty feeling that the MSFS team may have abandoned that method which could explain why a lot of their engine stuff is somewhat off
Roy
 
M

MarkRWatney

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unitedstates
I will head over there and have a look, Roy! Thanks for that pointer (non-NULL).

Being that this is a "sim" and they do not have any way of measuring everything like you can in the real-world, sacrifices must or could be made. This may be one of those situations.

I haven't tested the N1 percent in any of the other Jets yet and will. This still, maybe just a WT-CJ4 issue.
 
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