Syd Posted December 20, 2020 Posted December 20, 2020 Recently I've been looking into how realistic the weather system is in DCS in relation to barometric altimeter indications - "not great not terrible" as one would say. First, I was checking ISA athmosphere and for some reason ED decided to use 16 Celcius degrees instead of 15 as standard temperature. Not a big problem there. Once you set 16*C and 29.92 everything is as it should be - baro alt equals your amsl alt at all time. Then I looked into altimeter temperature error that occurs in different than standard temperatures (16*C in DCS). It is modelled, only real world equations don't apply. I think ED even modelled stratosphere layer since error is getting bigger above 35000ish ft. Lastly I decided to check how changing QNH setting influences altimeter. And here's my problem. If I'm correct, while temp is standard (16*C) then once you set altimeter to your mission QNH setting, indications of baro alt and AMSL should always match. But they don't. There is some strange error that occurs, similar to the temperature one (the higher you are the bigger it gets). I don't have a lot of modules but from what I saw it happens in F16 and F18 (that's why I'm posting it here). A10 for example does this right. Temperature error I mentioned above looks/behaves the same in all my official modules. I know QNH/pressure system in DCS is deeply flawed from the start (QNH shouldn't be called that for start, since it goes out the window once the temperature is different than 16*C) but this is a really strange behaviour. I get that DCS is not FS/X-Plane but is dev team aware of that error? Or maybe I'm wrong and it should be like that? 2
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