In REAL WORLD: Atmospheric pressure usually decreases when humidity increases because moisture in the air displaces heavier nitrogen and oxygen molecules, reducing the weight of the air in the area.
Long response :
Explanation:
Water is 2 hydrogen atoms and 1 oxygen atom. The atomic mass of hydrogen is approximately 1. The atomic mass of oxygen is approximately 16. That totals 18 approximately.
The main constituent of the atmosphere is molecular Nitrogen, in other words 2 nitrogen atoms. The atomic mass of each Nitrogen atom is approximately 14. Therefore the total is 28.
That is the math of it, water is lighter than nitrogen. Increased humidity (absolute humidity not relative humidity) will always lower air pressure.
Furthermore the 2nd main constituent of air is molecular oxygen. 2 oxygen atoms have a molecular mass of 32. Much higher than that of water vapor.
Another way to look at it is of course density. The reason that water vapor is less dense than dry air is because of the mass of the molecules. Water vapor molecules have less mass and the formula for density is mass /volume. The higher the mass the higher the density for a given volume. That is also why, as Truong-Son state, the temperature has to remain constant. Temperature is proportional to volume according to Charles’s Law.
I think msfs is ahead in so many ways, it’s funny that when you get a controller who say about your hight they treat it as a msfs problem when in fact it’s all the others that are working things out different to real life.. Do you know that if you use a 3rd party weather injector it is the same or does it match vatsim hights.
Excellent summary!
Btw would you mind checking if the MSFS displayed altitude on the altimeter correctly reacts to a change in the altimeter setting? I think it doesn’t. For example, when on a FL360 a change of the altimeter from std to 1012 will change the altitude displayed by way too much, around 80 ft, while it should only change by about 26 ft, I.e. by as much as the whole pressure column translates when the surface reference changes by 1 hPa.
I’ll throw one in here.
You don’t have near the amount of moisture in the upper atmosphere as you would in the lower, therefore I wouldn’t think the change in barometric pressure would be linear in a given column.
Moisture has relatively much smaller effect on the density and the pressure than height and temperature so it’d be ok to ignore it.
I was just pointing out a potential conceptual problem with the pressure and height calculations in MSFS.
Yep, I was pointing out maybe why in your conceptual problem.
The change throughout the height of a column would not be linear.
The same change at surface may not apply at FL360, due to moisture and heat.
This is because VAT-Spy shows your true altitude, not your pressure altitude or indicated altitude. And other pilots see you at your true altitude as well. Controllers see you at your pressure altitude when you’re above the transition layer, and they see you at your true altitude when you’re below the transition layer.
Great to see you’re still monitoring this! Have there been any changes to your proposed fix? Is MSFS correctly providing the variables you need to proceed?
No changes to the proposed workaround. I’ve been discussing it with other VATSIM client developers. It’s likely we won’t implement anything until after the new high-speed position updates (known as project Velocity) are implemented.
AFAIK there are no bugs in the values that MSFS currently provides via SimConnect.
So is it an issue with Vatsim controllers? Should I not fly this sim or is leaving “msfs” in the remarks good enough?
It’s good to see a developer interacting with the community. Thanks to you sir, keep up the good work and good luck!
On an unrelated note, I find it odd that MSFS made a instagram post a while back about some sort of “partnership” with VATSIM. If they had this partnership how could they let something like this happen? And why? Was this not tested with the higher ups at VATSIM? Just weird.
I know it has nothing to do with vPilot so don’t take this as me speaking about your software. Just saying it’s weird.
Maybe someone should tell Vatsim - they seem to have about the same NO Success communicating with Asoso, that most others 3rd party Developers seem to ??
Otherwise, we would be able to see labels on Vatsim Aircraft in MSFS, and see MSFS MP Planes + labels in LNM.
After implying that it seems to be an OVERSIGHT in a Q&A over 6 months ago, it still has not been addressed.
Partnership as advertised before release turned into something comic. Look at what they said in the video announcing partnership with Meteoblue or Cessna and then look at MSFS now … Same goes for Vatsim partnership.
