• Which the release of FS2020 we see an explosition of activity on the forun and of course we are very happy to see this. But having all questions about FS2020 in one forum becomes a bit messy. So therefore we would like to ask you all to use the following guidelines when posting your questions:

    • Tag FS2020 specific questions with the MSFS2020 tag.
    • Questions about making 3D assets can be posted in the 3D asset design forum. Either post them in the subforum of the modelling tool you use or in the general forum if they are general.
    • Questions about aircraft design can be posted in the Aircraft design forum
    • Questions about airport design can be posted in the FS2020 airport design forum. Once airport development tools have been updated for FS2020 you can post tool speciifc questions in the subforums of those tools as well of course.
    • Questions about terrain design can be posted in the FS2020 terrain design forum.
    • Questions about SimConnect can be posted in the SimConnect forum.

    Any other question that is not specific to an aspect of development or tool can be posted in the General chat forum.

    By following these guidelines we make sure that the forums remain easy to read for everybody and also that the right people can find your post to answer it.

Just a test

T

teson1

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Just testing - can't postmessages in forum.

Edit: Found what was wrong; Seems the message editor does not accept the word "x_replace" in a message under some circumstances... (Note I had to put an "x_" before the r-word for the message to pass.)
In other circumstances the r-word goes through... Strange...
 
Last edited:
T

teson1

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Maybe something wrong with the message I'm trying to test?

... Yes ...

Edited and trying to repost...

It's been a long time, and Klem has solved his issue...
However, I like to close open questions, so here's some more information from a discussion over at flightsim.

... Removing part of the message to find out where the error is...
 
T

teson1

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Next part...

* Here's how FS calculates "IAS"; unfortunately it's wrong.

"FS IAS" = "FS CAS" = sqrt(Pa/Pssl) * sqrt(1+M^2/4+M^4/40) * M * Assl

This equation exactly fits the "IAS"/TAS test data in FS2004.
However, this equation does not give the correct CAS/IAS.

Index
M: Mach number
Pa: ambient pressure
Pssl: standard atmosphere pressure, sea level
Assl: speed of sound with standard atmosphere at sea level

* Correct relation between TAS (=M*Aa) and CAS is the following:

CAS = sqrt( ( Pa/Pssl * ( (1 + 0.2*M^2)^3.5 - 1 ) + 1 )^(1/3.5) - 1 ) / 0.2 ) * Assl

(valid for M<1)

...
 
T

teson1

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Ok. That went through ok... next part...

Correct IAS may be calculated as function of Mach number and ambient

...
 
T

teson1

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...

Correct IAS may be calculated as function of Mach number and ambient pressure

...
 
T

teson1

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france
It's been a long time, and Klem has solved his issue...
However, I like to close open questions, so here's some more information from a discussion over at flightsim.

* Here's how FS calculates "IAS"; unfortunately it's wrong.

"FS IAS" = "FS CAS" = sqrt(Pa/Pssl) * sqrt(1+M^2/4+M^4/40) * M * Assl

This equation exactly fits the "IAS"/TAS test data in FS2004.
However, this equation does not give the correct CAS/IAS.

Index
M: Mach number
Pa: ambient pressure
Pssl: standard atmosphere pressure, sea level
Assl: speed of sound with standard atmosphere at sea level

* Correct relation between TAS (=M*Aa) and CAS is the following:

CAS = sqrt( ( Pa/Pssl * ( (1 + 0.2*M^2)^3.5 - 1 ) + 1 )^(1/3.5) - 1 ) / 0.2 ) * Assl

(valid for M<1)

...
 
T

teson1

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...

Correct IAS may be calculated as function of Mach number and ambient pressure (which are available as FS A: variables, all other variables are constants).

...
 
T

teson1

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...

Correct IAS may be calculated as function of Mach number and ambient pressure (which are available as FS A: variables, all other variables are constants).
Calculated IAS can be used to replace

...
 
T

teson1

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The following part brings me to a "Internet explorer can not display this page" if left within the text ... ???

...

false "FS IAS" in airspeed gauges.

...
 
T

teson1

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It's been a long time, and Klem has solved his issue...
However, I like to close open questions, so here's some more information from a discussion over at flightsim.

* Here's how FS calculates "IAS"; unfortunately it's wrong.

"FS IAS" = "FS CAS" = sqrt(Pa/Pssl) * sqrt(1+M^2/4+M^4/40) * M * Assl

This equation exactly fits the "IAS"/TAS test data in FS2004.
However, this equation does not give the correct CAS/IAS.

Index
M: Mach number
Pa: ambient pressure
Pssl: standard atmosphere pressure, sea level
Assl: speed of sound with standard atmosphere at sea level

* Correct relation between TAS (=M*Aa) and CAS is the following:

CAS = sqrt( ( Pa/Pssl * ( (1 + 0.2*M^2)^3.5 - 1 ) + 1 )^(1/3.5) - 1 ) / 0.2 ) * Assl

(valid for M<1)

Correct IAS may be calculated as function of Mach number and ambient pressure (which are available as FS A: variables, all other variables are constants).
... false FS IAS in airspeed gauges.

For further details see the original discussion at flightsim:
http://www.flightsim.com/vbfs/showthread.php?224097-Is-IAS-indicated-wrongly-by-FS

Gunter
 
T

teson1

Messages
130
Country
france
It's been a long time, and Klem has solved his issue...
However, I like to close open questions, so here's some more information from a discussion over at flightsim.

* Here's how FS calculates "IAS"; unfortunately it's wrong.

"FS IAS" = "FS CAS" = sqrt(Pa/Pssl) * sqrt(1+M^2/4+M^4/40) * M * Assl

This equation exactly fits the "IAS"/TAS test data in FS2004.
However, this equation does not give the correct CAS/IAS.

Index
M: Mach number
Pa: ambient pressure
Pssl: standard atmosphere pressure, sea level
Assl: speed of sound with standard atmosphere at sea level

* Correct relation between TAS (=M*Aa) and CAS is the following:

CAS = sqrt( ( Pa/Pssl * ( (1 + 0.2*M^2)^3.5 - 1 ) + 1 )^(1/3.5) - 1 ) / 0.2 ) * Assl

(valid for M<1)

Correct IAS may be calculated as function of Mach number and ambient pressure (which are available as FS A: variables, all other variables are constants).
Calculated IAS ... false FS IAS in airspeed gauges.

For further details see the original discussion at flightsim:
http://www.flightsim.com/vbfs/showthread.php?224097-Is-IAS-indicated-wrongly-by-FS

Gunter
 
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