My apologies. Further investigation, specifically of the default b737_400 aircraft, shows the max temp at which MS decided that contrails should appear is set at -30C (in the GeneralEngineData section of the aircraft.cfg file).

 

Jan Rosenberg looked into the actual mechanics of the contrail.fx effect and tinkered with both the look and duration of the effect. His work is available in the file AI-FX.zip and it is from this Readme that I was quoting. If you are still confused then I suggest you contact him.

 

As for "hits" ... that's the number of page returns when you Google "FS9 default contrail max temp".

 

Dorian

I still don't get it.  So that's what it shows.  Is that a good number or a bad number?  And whichever it is, the temperature number is something that is set per aircraft?  So each aircraft has to be changed separately?  Not something that is global?

 

And is it ai_fx.zip or ai-fx.zip?  Are we talking about two different files?

"I still don't get it.  So that's what it shows.  Is that a good number or a bad number?"

 

Just to show you that Google is your friend and that the subject has been discussed previously. You could have searched it out for yourself.

 

"And whichever it is, the temperature number is something that is set per aircraft?"

 

Yes.

 

"So each aircraft has to be changed separately?"

 

Unless you have a horde of friendly elves hidden away in a cupboard somewhere who are prepared to change the numbers for you, yes.

 

"Not something that is global?"

 

Do a Library search for "Contrails"

 

"And is it ai_fx.zip or ai-fx.zip?"

 

High-Altitude Contrail 50 Miles Long

 

File Description:
FS2004 High-altitude contrail 50 miles long. Use w/ default AI aircraft. High- altitude contrails are now enabled by MS for use on each aircraft, jet or prop, single or multi-engine, by using the FS9 version of the aircraft.cfg "EFFECTS" section to specify them. The temperature below which the contrails occur can also be defined in aircraft.cfg by the user. Included in d/l are new AI contrail, and revised aircraft.cfg w/folder structure to make a extra "AI" copy of default AC. This allows default(or other)contrail to be used for "hand" flying same aircraft. Easy manual installation with all new filenames.

Filename: ai_fx.zip License: Freeware Added: 28th September 2003, 19:12:42 Downloads: 14356 Author: Jan Rosenberg Size: 91kb

 

"Are we talking about two different files?"

 

No, I was simply suffering a case of fat finger syndrome.

 

Dorian

"I still don't get it.  So that's what it shows.  Is that a good number or a bad number?"

 

Just to show you that Google is your friend and that the subject has been discussed previously. You could have searched it out for yourself.

 

"And whichever it is, the temperature number is something that is set per aircraft?"

 

Yes.

 

"So each aircraft has to be changed separately?"

 

Unless you have a horde of friendly elves hidden away in a cupboard somewhere who are prepared to change the numbers for you, yes.

 

"Not something that is global?"

 

Do a Library search for "Contrails"

 

"And is it ai_fx.zip or ai-fx.zip?"

 

High-Altitude Contrail 50 Miles Long

 

File Description:

FS2004 High-altitude contrail 50 miles long. Use w/ default AI aircraft. High- altitude contrails are now enabled by MS for use on each aircraft, jet or prop, single or multi-engine, by using the FS9 version of the aircraft.cfg "EFFECTS" section to specify them. The temperature below which the contrails occur can also be defined in aircraft.cfg by the user. Included in d/l are new AI contrail, and revised aircraft.cfg w/folder structure to make a extra "AI" copy of default AC. This allows default(or other)contrail to be used for "hand" flying same aircraft. Easy manual installation with all new filenames.

Filename: ai_fx.zip License: Freeware Added: 28th September 2003, 19:12:42 Downloads: 14356 Author: Jan Rosenberg Size: 91kb

 

"Are we talking about two different files?"

 

No, I was simply suffering a case of fat finger syndrome.

 

Dorian

Thanks for the clairification.  On most of it.  I still don't know about the temperature though.  You said I could have search for it myself, and I suppose that's true.  But, the reason why I come to this forum for questions is because I've had pretty good luck with people not only willing to help but who are able to help because they have had the issues/problems/resolutions themselves.

And, as I have already stated, the general consensus amongst simmers, given the limitations of FS9 as a realistic simulation platform, is -27C.

And then you said -30.

Which is the MS default value. Your choice.

Just throwing the cat amidst the pigeons ... if I'm reading this correctly, the Appleman Chart suggests a range anywhere between -26.15C and -69.61C, dependent upon hPa (pressure) and RH (relative humidity).

 

Personally, I have no idea how well the simulator models these situations at altitude, so it might be that the MS default of -30C may be a good enough compromise for FS9. Who knows?