What has happened to thermals?

Question

I have just updated to XPlane 11 v1.02.

Before the update I was having quite a lot of excellent soaring flights in the ASK 21 glider. Thermals worked very much like I remember in the real thing.

After the upgrade I find the "thermals" are completely broken with no apparent structure, and I get both varios indicating 2M/s lift with the altimeter showing steady descent!

Please fix whatever has been changed ASAP.

Answer 1

You'll need to be more specific about how to test for the difference. No one on the X-Plane team is an expert on glider flying so we'll need you do give us detailed information. Make sure you are using only default aircraft and scenery. Please file a bug here with the exact steps outlining how to see the difference between 11.01 and 11.02.

Comments

I have filed a bug.

In the mean time, is there any way I can revert to the previous version of XPlane 11?

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Once a version has gone final (as 11.02 has now) you can only get back to an older version if you have made a personal back up. Only 11.02 is now hosted on X-Plane's servers.

Our goal is to make the sim as realistic as possible, so if you have any documents or knowledge on how thermal modeling isn't accurate in X-Plane, Austin will probably be interested in seeing it.

Answer 2

Hi, even in XP10 the thermals where completely wrong, unless you are used to North os South America extraordinary conditions. In simple terms: Xplane depicts something like a vertical cylinder with constant ascending current...not at all realistic.
For what I tried, nothing changed in XP11: no variation, no cumulus at the top, no wind movement, no temperature variation (broken thermals when air layer changes) etc etc.
Completely unrealistic.

I did a 3 projector/3 PC sim in 2014 at my club and waited soooo long for somebody able to fix the behavior with thermals and gliders, but i found only a modified ASK21 model and a python script that tries to simulate better the thermals (it does a good job, but they stopped the develpement months ago...). I'm not able to do that by myself...

Sadly...I did a great job with that incredible glider sim (240° FOV)...but now I can say it was almost a waste. Better to use Condor or Condor 2 (next year probably) with all its limitation.

Comments

I didn't bother trying to thermal in XPlane 10, but I certainly did in XPlane 11, and found it great up to the change to v11.02. I have over 300 hours of actual glider and motor glider experience, and I found the XPlane ASK21 very similar to lots of my glider flying at Armidale, Narromine, Leeton, Forbes, Toowoomba, and Narromine (all Australian towns) in the sense that once you encountered a thermal, you had to do some work to centre it and then you could climb with minor corrections until the thermal ran out. I didn't really expect the thermals would be related to cumulus clouds in the sim, although that would be nice, but I did detect a possible connection to the terrain in the sim. It might have been my imagination, but on several occasions I managed flights well over 200km (using only 2 or 3 thermals and porpoising the rest of the time) in the sim until v11.02 spoilt the consistency of something like a roughly cylindrical thermal.