Calculate VS at touchdown - sloped rwys

[ThePedro]

Hello,

In order to calculate the landing rate I'm using the offset 0x030C.

Apart the known problems of bounces, there is another problem in case of sloped runways.

I've found a variable in Simconnect called "PLANE TOUCHDOWN NORMAL VELOCITY".

https://docs.flightsimulator.com/html/Programming_Tools/SimVars/Aircraft_SimVars/Aircraft_Misc_Variables.htm?rhhlterm=plane touchdown normal velocity&rhsearch=PLANE TOUCHDOWN NORMAL VELOCITY

Can it be implemented also in fsuipc?

Here a sample project using it:

https://github.com/scelts/gees/tree/master

 

Thanks

Umberto

[John Dowson]

51 minutes ago, ThePedro said:

Can it be implemented also in fsuipc?

Yes I could add that, and maybe better than using VERTICAL SPEED while on ground. I can switch to using the simvar PLANE TOUCHDOWN NORMAL VELOCITY for offset 0x030C, but if you want to use this now you can add this to a spare/free FSUIPC offset using the facilities provided (i.e. via the myOffsets.txt file).

It may be better to add this to a new distinct offset. If you could add that to an offset and compare the values and let me know if you think offset 0x030C should be replaced or add this to a new offset, that would be great,

Cheers,

John

 

[ThePedro]

Thank you John for the quick answer. 

I'll try using a free offset and I'll send u the compared values, in order to see if it deserves to change the original offset simvar

 

Umberto 

[John Dowson]

12 hours ago, ThePedro said:

I'll try using a free offset and I'll send u the compared values, in order to see if it deserves to change the original offset simvar

That would be good, thanks.

[John Dowson]

On 1/7/2025 at 8:43 PM, ThePedro said:

I'll try using a free offset and I'll send u the compared values, in order to see if it deserves to change the original offset simvar

I have added the PLANE TOUCHDOWN NORMAL VELOCITY simvar to offset 0x0654 (as a 4-byte float, in Ft/s) in the attached version if you would like to try this.

John

FSUIPC7.exe

[ThePedro]

Thank you so much John, I'll test in these days

Umberto

[ThePedro]

Hello John,

a couple today's tests with TBM9:

I converted the new offset in ft/m from ft/s and changed sign in order to be comparable with the original one

LIQL
14.25.58 - [Leg] Landing detected. Landing rate: -162 fpm (Last VS: -142 - GForce: 1.21 - Normal: -192.0) RWY 10 

VNLK
14.39.25 - [Leg] Landing detected. Landing rate: 945 fpm (Last VS: 1030 - GForce: 1.50 - Normal: -432.3) RWY 06
14.44.14 - [Leg] Landing detected. Landing rate: 478 fpm (Last VS: 273 - GForce: 1.00 - Normal: -244.7)  RWY 06
  
LFLJ  
15.03.35 - [Leg] Landing detected. Landing rate: 1709 fpm (Last VS: 1754 - GForce: 1.38 - Normal: -407.0) RWY 22
15.11.15 - [Leg] Landing detected. Landing rate: 1278 fpm (Last VS: 1200 - GForce: 1.34 - Normal: -262.9) RWY 22


LIDP
15.18.21 - [Leg] Landing detected. Landing rate: -54 fpm (Last VS: -96 - GForce: 1,05 - Normal: -88,9) RWY 02 
15.23.13 - [Leg] Landing detected. Landing rate: -165 fpm (Last VS: -149 - GForce: 1,22 - Normal: -231,3) RWY 20 

The values seems reliable.

I will continue test in bigger airports with liners and I'll let you know
 

 

[John Dowson]

1 hour ago, ThePedro said:

I converted the new offset in ft/m from ft/s and changed sign in order to be comparable with the original one

Yes - I left it in the standard units provided. I could convert to m\s or ft\min if thats more useful...but the units shouldn't matter as long as you know what they are/are documented. As I am adding this as a new value, I can add in any units. 

[ThePedro]

I think you can let it in original units (ft/s). 

Thank you.

[John Dowson]

2 hours ago, ThePedro said:

I think you can let it in original units (ft/s). 

Ok, I will leave it as is in the version I posted above.