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Old 03-10-2018, 11:12 PM   #1
Divadov
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Default Barometric Pressure

When will it work the barometric pressure?

The barometric pressure indicated in the briefing never it's the same that in the environment of the game, always I must to adjust the barometer to mark the altitude of the airport.
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Old 03-10-2018, 11:25 PM   #2
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Originally Posted by Divadov View Post
When will it work the barometric pressure?

The barometric pressure indicated in the briefing never it's the same that in the environment of the game, always I must to adjust the barometer to mark the altitude of the airport.
Good try…

Brief pressure means QNH, that's sea level equivalent atmospheric pressure and gives you current altitude MSL in the altimeter. Of course it's never equal to QFE, current pressure in your ground height, that's airport altitude and that's what your altimeter points when, guess what, QNH is set .

Next time remember you have to learn to walk before "runt"…

https://en.wikipedia.org/wiki/QNH


S!
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Old 03-11-2018, 12:08 AM   #3
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Originally Posted by Ala13_ManOWar View Post
Good try…

Brief pressure means QNH, that's sea level equivalent atmospheric pressure and gives you current altitude MSL in the altimeter. Of course it's never equal to QFE, current pressure in your ground height, that's airport altitude and that's what your altimeter points when, guess what, QNH is set .

Next time remember you have to learn to walk before "runt"…

https://en.wikipedia.org/wiki/QNH


S!
Uhm...

No, he's actually correct.

The altimeter setting used in the mission editor is theoretically QNH. But it's always incorrect relative to what it should be by ± a few decimals of inHg.

The easiest solution, and what we often do in real life to set the altimeter, is just to use the known elevation of your airfield and set it to that. For example, the field elevation at Vaziani at runway 13 is 1526 feet. Instead of bothering with the inaccurate briefing QNH, or using QFE which is not practical unless you are remaining within a close distance to your departure airfield, just set your altimeter to the known field elevation.
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Old 03-11-2018, 12:33 AM   #4
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Yep, this has been mentioned quite a few times. I haven't seen any acknowledgement from ED on it.
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Old 03-11-2018, 08:48 AM   #5
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Originally Posted by Ala13_ManOWar View Post
Good try…

Brief pressure means QNH, that's sea level equivalent atmospheric pressure and gives you current altitude MSL in the altimeter. Of course it's never equal to QFE, current pressure in your ground height, that's airport altitude and that's what your altimeter points when, guess what, QNH is set .

Next time remember you have to learn to walk before "runt"…

https://en.wikipedia.org/wiki/QNH


S!
"When the wise man points to the moon, the fool looks at the finger"

I know what is QNH and QFE, I have 30 years of experience in flight!!!
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Old 03-11-2018, 11:40 AM   #6
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Originally Posted by Divadov View Post
"When the wise man points to the moon, the fool looks at the finger"

I know what is QNH and QFE, I have 30 years of experience in flight!!!
Good for you, tell that to someone not being also RL pilot mate , I think many here are and that's why we enjoy DCS.



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Originally Posted by Kippy View Post
Uhm...

No, he's actually correct.

The altimeter setting used in the mission editor is theoretically QNH. But it's always incorrect relative to what it should be by ± a few decimals of inHg.

The easiest solution, and what we often do in real life to set the altimeter, is just to use the known elevation of your airfield and set it to that. For example, the field elevation at Vaziani at runway 13 is 1526 feet. Instead of bothering with the inaccurate briefing QNH, or using QFE which is not practical unless you are remaining within a close distance to your departure airfield, just set your altimeter to the known field elevation.
I used to fly from a non controlled aerodrome, still one could set nearest airport radio and know QNH, or maybe when opening FP tower told us QNH. It never matches the pressure and/or altitude we set in ground but we don't complain for the bug . So into DCS I don't know if it's "inaccuracy" or being it for the whole map once set in ME there are actually pressure variations depending on where you spawn, not to mention instrument error/variations. Do we know it's a "bug"? Because it's so funny how it matches real life behaviour and I wouldn't complain because of that .



S!

P.S.: Divadov, for the record, didn't realise you were an E69 until now, but people get here to complain about everything all of the time for no brainer reasons when not very well known issues, or even features they just don't know DCS have… those are the funniest part of it. Just getting to the forums and saying "this is wrong" without further info or input is not very helpful. Plus it was late last night when I answered, sorry if it sounded any harsh, no offence mate .
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Old 03-11-2018, 03:46 PM   #7
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Originally Posted by Ala13_ManOWar View Post


I used to fly from a non controlled aerodrome, still one could set nearest airport radio and know QNH, or maybe when opening FP tower told us QNH. It never matches the pressure and/or altitude we set in ground but we don't complain for the bug . So into DCS I don't know if it's "inaccuracy" or being it for the whole map once set in ME there are actually pressure variations depending on where you spawn, not to mention instrument error/variations. Do we know it's a "bug"? Because it's so funny how it matches real life behaviour and I wouldn't complain because of that .
Hello, also a real world pilot of several years here flying out of an uncontrolled airport equipped with an AWOS. (KC62) I'm not sure what the typical grade of weather equipment is typical over there , but after seven years of flying for me, I've never been given QNH that was anomalous by an AWOS that wasn't malfunctioning or by ATC. But maybe I've been spoiled by my country; aviation infrastructure here is top notch compared to other places in the world. Pressure variations are why, when flying cross country, we continually tune the AWOS from airports we pass nearby to get their altimeter information, or even if we're up for long durations in and out of the same airport, we of course, will check AWOS before landing. Not really an option in DCS, unless your mission makers put looped radio transmissions for AWOS into the mission, and even then, they're static and unchanging.

To my knowledge, DCS doesn't simulate instrument errors.

To conclude, no, it doesn't match real world behavior. It may be correct behavior if you're used to flying out of an airport with broken or no automated weather observation systems. Yes, there are pressure variations in the real world, but DCS's mission editor, when using static weather, should set the weather for the whole map without pressure variations, to my knowledge.
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Old 03-11-2018, 09:05 PM   #8
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Quote:
Originally Posted by Kippy View Post
Uhm...

No, he's actually correct.

The altimeter setting used in the mission editor is theoretically QNH. But it's always incorrect relative to what it should be by ± a few decimals of inHg.

The easiest solution, and what we often do in real life to set the altimeter, is just to use the known elevation of your airfield and set it to that. For example, the field elevation at Vaziani at runway 13 is 1526 feet. Instead of bothering with the inaccurate briefing QNH, or using QFE which is not practical unless you are remaining within a close distance to your departure airfield, just set your altimeter to the known field elevation.
Even if you do as you say, the indicated altitude will start to differ from the F2 external view altitude (which is the one used by AI, so it's what we should probably consider as the in-game "true" altitude) once you start climbing. I don't know if this affects all the modules, but it does affects the F-86, for example.
I don't think that it is a problem of QNH accuracy, since the inaccuracy grows not linearly with altitude. I believe it's actually an altimeter bug.
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Old 03-12-2018, 12:03 AM   #9
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Even if you do as you say, the indicated altitude will start to differ from the F2 external view altitude (which is the one used by AI, so it's what we should probably consider as the in-game "true" altitude) once you start climbing. I don't know if this affects all the modules, but it does affects the F-86, for example.
I don't think that it is a problem of QNH accuracy, since the inaccuracy grows not linearly with altitude. I believe it's actually an altimeter bug.
I have the same problem in the UH-1. Starting on the ground at 2381' elevation, I set the altimeter to 2380', with a pressure of something like 30.40 (despite pressure in ME set to 30.10). As I climb up to 4700' according to my altimeter, the F2 view status bar indicates an altitude of 5000'.

You can also see this with tankers, where you set them to orbit at 18,000' and instead they orbit at 17,xxx'.
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Old 03-12-2018, 02:38 AM   #10
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Originally Posted by catt42 View Post
Even if you do as you say, the indicated altitude will start to differ from the F2 external view altitude (which is the one used by AI, so it's what we should probably consider as the in-game "true" altitude) once you start climbing. I don't know if this affects all the modules, but it does affects the F-86, for example.
I don't think that it is a problem of QNH accuracy, since the inaccuracy grows not linearly with altitude. I believe it's actually an altimeter bug.
I see... good observation.
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