A chronic "stock" Flight Model glitch which appears seemingly proper

[alfa2]

I'm very late in discovering this chronic glitch, however i think anybody should be aware of it.

In the [FlightControl] section of any jet  fighter with an afterburner there is an entry stating "MachLimitDry=XX" where "XX" is a value usually less than unity. It's purpose is obvious, to limit AB equipped AI jets, or actually any AI jet to break the sound barrier with its "dry"  non augmented thrust. As happens usually this [FlightControl] setting also affects the player controlled planes, regardless of their drag & thrust modelling fidelity. However, this setting is seemingly proper but in fact it is a nuisance, since it introduces a significant FM glitch. It results to  zero engine dry thrust above the "XX" value limit, while in the cockpit you can't observe it since all indications remain proper (rpm's, fuel flow, EGT's etc). It is only the dry thrust being suppressed which in fact is a big mistake. The turbojet and turbofan jet engines always produce a core "dry" thrust by the hot exhaust stream of the core combustion phase in every speed band (subsonic/transonic/supersonic). Their "wet" thrust  is a result of   injecting fuel directly into the said hot exhaust stream behind the engine's turbine, using leftover oxygen to trigger a second combustion phase. This second combustion rapidly heats and expands the exhaust gases, forcing them out of a variable-geometry nozzle at a much higher velocity and therefore producing a much higher "wet thrust".

From my experiments with it, If you totally omit this setting it will be imposed by default (it is hard coded) and therefore one solution remains. To replace it with "MachLimitDry=ZZ" where "ZZ" is the value of  the "MachLimit=ZZ"entry which also  found in the [FlightControl] section. After this change the jet engine operation is normally restored and thrust modelling is then proper.

Instructions on how to correct the problem:

1. If the plane you're interested to fix  is a download product, either created from scratch or a modded product, find the aircraft's "XYZ_Data.ini" file (Where XYZ is the aircaft's file name) and scroll down to the [FlightControl] section. There you'll find two statements "MachLimitDry=" and "MachLimit=". All you have to do is change the value of the MachLimitDry= and assign to it the value of MachLimit=.

2. If the plane is a stock TW product you actually need to essentially compose a new plane using the files contained in the cat files of the stock TW files. In this new plane you're going to do the edit described in instruction #1 above. This isn't difficult at all but it needs to follow a few steps. If you'are interested in such a case PM me and I'll do my best to help you out.

Edited Sunday at 09:35 PM by alfa2

[Goob113870]

oh wow! Good catch. so all you have to do is a little editing then in the [FlightControl] section

[alfa2]

FYI We'll post replacement aircraft data .ini files for our recent uploads with Sophocles. Until then please just do the simple edit I've described above to the respective files. (Correct the MachLimitDry= value to be equal  to the value of the MachLimit=)

[Wrench]

Need to correct the statement in the original post -- it should read as:

"FlightControl section in the aircraft's Data ini"

simply because there's a whole lot of folks, new or otherwise,  that won't know where to look for it. Might want to also tell them, that if it's a stock bird, they'll need to extract the relevant data ini from whichever CAT it's in, and place it INTO said aircraft's main folder. 

 

[alfa2]

Ok Wrench, OP edited with the instructions you suggested. However the stock planes' fix is a bit more convoluted , so if anyone is interested I can help him do the job.

[pachinkoparlorking]

58 minutes ago, alfa2 said:

Ok Wrench, OP edited with the instructions you suggested. However the stock planes' fix is a bit more convoluted , so if anyone is interested I can help him do the job.

I'm a bit curious as to the process for fixing the stock planes myself. I'm not an expert or anything but i always like to learn how to mod this game better.

Edited Sunday at 10:36 PM by pachinkoparlorking

[VonS]

@OP, a good catch and definitely a better solution than relying on the stock MachLimitDry values of ~ 0.85 to 0.95 (that are a wee bit on the low side). Do keep in mind, however, that setting Dry and Wet to the same value (haven't tested this but perhaps worth some tests) - might result in a situation where jets will then super-cruise or over-accelerate in dry power without ever needing afterburner. For what it's worth, my (little) FM Consolidated Pack for SF2, specifically the flogger tweaks contained therein, err on the conservative side of setting MachLimitDry to between ~ 1.05 and 1.15. This allows the engine to keep producing core thrust through transonic regimes and in dives, but still forces the player and AI to plug in afterburner in order to push past Mach 1.1 or so in level flight.

Cheers all & good (jet-age) FM tweaking to you,

[alfa2]

7 hours ago, pachinkoparlorking said:

I'm a bit curious as to the process for fixing the stock planes myself. I'm not an expert or anything but i always like to learn how to mod this game better.

It isn't something difficult. However it is easier to do it for a friend than explaining how to do it ...

So hopefully that I'm not making any mistake, the instructions to do the OP simple edits are the following:

Step 1. Download the default TW "cat" files decompressing  utility from here : http://download.thirdwire.net/files/dl/SF2_Extractor_setup_Mar2012.exe or this utility "Mues Toolbox - Utilities / Editors - CombatACE" from combatace.

Step 2  Install the SF2_Exctractor or the Mues Toolbox utility. In my case I'm using Mues Toolbox so the instructions below refer to this application. In any case use of the default extractor is very similar.

Step 3. Read the attached readme file regarding the set up of the Mues Toolbox extractor.

Step 4. Follow all readme set up instructions to enable the utility find the folders of your default TW SF2 installation and also define where it will extract the compressed file folders' content.

Step 5. Run the Mues Toolbox CATExtractor.exe

Step 6. When you use the extractor you'll see the the interface attached. The upper window contains the directory of the compressed "cat" files and the lower window depicts the contents of this particular compressed file. 

Step 7. You have to browse through all objectdata0xx.cat or DLCdata00x.cat files by "ticking" each one to see its content in the lower window. Once you find the plane you're interested to modify do the following:

• Extract the (aircraft filename) ini file. It is needed and it is helpful because it will contain all other files you'll need to extract.
• Open the (aircraft filename) ini file and note the filenames of the files mentioned in the [AircraftData] section.
• Locate the needed files and extract them one by one in your designated extraction folder (step 4 above) in a specific subfolder and give it the name you like. This name will be temporary and will be changed in step 8 below.
• Open the (aircraft filename) _data.ini file. 
• Go to the [FlightControl] section and align the MachLimit= and MachLimitDry= values as described in the original post.
• Save the data file

Step 8 Assign a new permanent subfolder name to your extraction subfolder of step7 3rd bullet above. the folder name has to be the same with the aircraft filename.

Step 9 Move the subfolder you have created to your mods director under the folders Objects/aircraft.

Your'e done. If you have a problem raise a call for help.

catextractor_readme.txt

[alfa2]

6 hours ago, VonS said:

@OP, a good catch and definitely a better solution than relying on the stock MachLimitDry values of ~ 0.85 to 0.95 (that are a wee bit on the low side). Do keep in mind, however, that setting Dry and Wet to the same value (haven't tested this but perhaps worth some tests) - might result in a situation where jets will then super-cruise or over-accelerate in dry power without ever needing afterburner. For what it's worth, my (little) FM Consolidated Pack for SF2, specifically the flogger tweaks contained therein, err on the conservative side of setting MachLimitDry to between ~ 1.05 and 1.15. This allows the engine to keep producing core thrust through transonic regimes and in dives, but still forces the player and AI to plug in afterburner in order to push past Mach 1.1 or so in level flight.

Cheers all & good (jet-age) FM tweaking to you,

If the drag/thrust fidelity is correct in principle, the Cold War and older player planes will never be able to supercruise. Many 4thGen + planes will most probably supercruise as AI's and possibly as player planes depending on their drag profiles. However to do and enjoy proper ACM/BFM you need to have a full thrust range otherwise you're stuck to AB only flight, which is not only wrong but a strong reason to loose many dogfights.