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Calculating landing rate from simconnect

S

scelt

Messages
7
Country
switzerland
Hi,

I'm looking at how to calculate the landing rate as in these landing challenges, but can't figure it out.
So I tried the variable "STRUCT WORLDVELOCITY". This gives you the vertical speed, and this is all great, but if the runway is sloped, it doesn't work (i.e. at Courchevel one has positive vertical speed during landing.
Then I tried "STRUCT SURFACE RELATIVE VELOCITY" thinking this will normalise this speed to ground, but it doesn't do that. The values are the same as the first one.
Then I tried to query for "RADIO HEIGHT" and do the math (delta height / time) but I cannot query the exact timestamp from the sim, and if I just time the simconnect responses and do the timing from there - doesn't work.

The closest I get to the actual landing rate value, is by checking the STRUCT WORLDVELOCITY before and after landing, but this again doesn't yield the numbers as in the sim's landing challenges.

Does anyone have an idea how should this be done properly? How does Asobo calculate it?
 
Ok, I'll reply myself, for any future reference. I found out that in the end, the best is to read "PLANE ALT ABOVE GROUND" in regular (fast) intervals of 10-20ms and then to take the average of the change in the last 100ms of the flight, before the "SIM ON GROUND" shows true. That's the only way it gets close to the ones Asobo calculated. Not perfect, but close.
Anything else, "STRUCT SURFACE RELATIVE VELOCITY", "VELOCITY BODY Y" etc just gives the vertical speed to the earth centre and one cannot do much with it, even on a mildly sloped runway (1-2deg +)
What's confusing is that when I tried, "STRUCT SURFACE RELATIVE VELOCITY" it doesn't normalise with the ground, and from the description, it should. Maybe this is a bug, I don't know.

Here's the code and the app I made with this: https://github.com/scelts/gees
 
That doesn't work if the runway is sloped, I wrote in the first question.
If the runway's uphill, you go with a positive vertical speed to land with 0fpm
If it's downhill, you go with more than -0fpm to land with 0fpm.

This is if the vertical speed is referenced to the earth's center, (or sea level). It needs to be referenced to the surface below the plane. This parameter I didn't find out. There's "STRUCT SURFACE RELATIVE VELOCITY", but it gives me the same value as the "Vertical Speed"
 
Simulation variable "PLANE TOUCHDOWN NORMAL VELOCITY" - represents the player’s plane speed according to ground normal from the last touchdown, ft/s. I guess that normal velocity works for sloped runways. Doesn't tested.
 
Prepar3DGuy said:
Simulation variable "PLANE TOUCHDOWN NORMAL VELOCITY" - represents the player’s plane speed according to ground normal from the last touchdown, ft/s. I guess that normal velocity works for sloped runways. Doesn't tested.
Click to expand...
And you got this variable name from where?
 
MSFS SDK v0.6.1 Content Configuration -> Variable Lists -> Simulation Variables- >Aircraft Position and speed data.
 
This is the new version of SDK?
I think this is the new variable - I'll definitely try it out!
 
Yep, updated the SDK, and documentation is now in the horrible, unsearchable windows help display.
This is the variable I was looking for. Takes runway slope into account, and I guess this is why it wasn't needed in the previous versions.
 
Odd... it's not listed as having been tested and working in the Content Configuration/SimConnect/SimConnect Status of Simulation Variables. Guess they're not keeping everything up-to-date.
 
how do I know the destination airport name ? I do not get a string for ATC RUNWAY AIRPORT NAME
 
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