hmmm, where'd my contrails go?

[Allen_Z]

They ought to be there @ 32,000 feet, yes?

[Groundbound1]

Don't do that just yet....

What is the temperature? Set it to 10 degrees F or so, and see if they return.

[Allen_Z]

Hey groundbound, thanks  :D

Same flight, switched to the 727, and you can see the temp on the FE report.

Contrails should be there

[Groundbound1]

You'd think so. What I meant though, is try setting the temperature to 10 F or less at ground level in the weather control panel. The sim will reduce the temp proportionately the higher you are. If you don't see them after that, we'll need to look for other possibilities.

Process of elimination.

[Allen_Z]

There is a standard at that altitude, it's always that cold, that's why contrails usually start at around 20-25 thousand feet.

I've never seen the temp vary at alt, regardless of ground temp. But, I guess there's always a first time

[MiltonShupe]

Contrails are controlled by air temperature.

This may vary with your aircraft as it is controlled by this statement in the aircraft.cfg.

max_contrail_temperature = -39.0 //(Stated in Celsius)

Here is what the SDK says about it:

max_contrail_temperature      max_contrail_temperature=-39.0      Ambient temperature, in Celsius, in which engine vapor contrails will turn on.

[microlight]

Hi Allen,

My advice would always be to use an uninstall/re-install only as an absolute last resort when all else has failed; I'm not a fan of the 'routine' uninstall and reinstall; my two installs on desktop and laptop are the original ones I put on some years back, even with all the mountains of add-ons I've put in since. (But then I'm pretty AR about how I upgrade my sim!)

Appearance/disappearance of FS effects is usually cause-and-effect (if you'll pardon the pun). If contrails have disappeared where they were there previously, and you haven't substantially changed your flying environmental conditions, then it's likely you may have done something that's affected the way they display. First thing to check is that the contrail effects files are still where they should be, in the 'effects' folder. Look for the files fx_contrail_l.fx and fx_contrail_s.fx. These effects are always on by default (governed by altitude and the 'activation' temperature that Milton stated above) so if these files are still there, then the effects should show. This is different to water, wake, touchdown etc. effects that are on/off switched from the aircraft.cfg.

Let us know if the contrail effects files are still there.

[Groundbound1]

[quote]There is a standard at that altitude, it's always that cold, that's why contrails usually start at around 20-25 thousand feet.

I've never seen the temp vary at alt, regardless of ground temp. But, I guess there's always a first time

[Allen_Z]

Awrighty then...

Went and checked the two planes that didn't have contrails, and they didn't have that line Mr Shupe gave us.

So I added it, you can see where the trail starts  ;D



Thanks for all the help. Guess I'll have to check aircraft.cfg files as I go, but that is easier than a re-install

[Groundbound1]

Remember, -39C is the default temp at which you should see contrails, so you don't HAVE to add that line to all your A/C. (In other words, if the temp is -39C, you should see a contrail behind your jets even if that line isn't there.)

Well, so long as you got'em back, then all is well again!

[MiltonShupe]

That is true Groundbound.

The only reasons you need the statement is if you wish to change the temperature that contrails will become visible, OR if it is a high altitude prop aircraft (turned off by default).