need track replay Gun Cross below horizon Hud Horizon estimation Wrong?

[fapador]

[fapador]

Hi all, a thing that has bugged me from release. The gun cross seems to  always be slightly above horizon even with a fully loaded plane. I don't know if its a gun cross position or a horizon line approximation not being correct. However,  years ago  I had a go at Lockheed's Martin Viper simulator and I remember  the gun cross  in line with horizon when landed or taxiing.

I post this video also where you can see at 1:32 the gun cross being below horizon. I don't know what exactly is the problem. It seems to me that the horizon is estimated differently on dcs but I am not too sure. It might have even something to do with the flat dcs maps???  The Hud projection????? Any opinions out there? 

 

PS: I can also note that the AOA bracket is in different position than in dcs on takeoff roll. The tape's bracket is in middle of -5degrees  while ingame it's quite below -5 degrees.

 

Edited March 31, 2022 by fapador

[Deano87]

I’d suggest it’s probably to do with the suspension modelling, the aircraft may be squatting too much on its main gear when loaded, or perhaps the nose gear is too stiffly sprung. It was noted in another thread that the nose of jet in the sim doesn’t bob up and down as much while taxing compared to the real thing.

[fapador]

I don't think so man. It happens even with a complete empty loaded plane, perhaps even slightly worse. Also look the hud tapes on  right and left, their top's part on dcs have noticeably larger distance from the horizon line than the ones in the video

Edited March 30, 2022 by fapador

[Sacarino111]

HI.

I can 't tell for sure, but is the F-16 aligned at that moment? If not, the HUD tapes have to change their position quite a bit, so maybe after alignement the cross move up...

Just a thinking...

Saluos.

Saca111

Edit; he is not aligning, as the message would have been in the low left of the HUD, but he still has a WARNING (FCS Bit?), so can't tell.

Edited March 30, 2022 by Sacarino111

[fapador]

 

19 minutes ago, Sacarino111 said:

HI.

I can 't tell for sure, but is the F-16 aligned at that moment? If not, the HUS tapes have to change their position quite a bit, so maybe after alignement the cross move up...

Just a thinking...

Saluos.

Here is Hud footage of f16 loaded with external fuel tanks and 2 maverick missiles on .  1:39 On takeoff role  cross seems to be more of less inline with horizon. At least not above as in dcs

 

 

Edited March 30, 2022 by fapador

[Deano87]

@fapadorIn that first real video you posted the jet is aligning so the horizon line in spurious and not relevant.

In the second video, you're correct the cross is slightly below the horizon line. Like I said I think a softer nose gear suspension would bring the cross down to where it should be.

[fapador]

5 hours ago, Deano87 said:

In that first real video you posted the jet is aligning so the horizon line in spurious and not relevant.

In the second video, you're correct the cross is slightly below the horizon line. Like I said I think a softer nose gear suspension would bring the cross down to where it should be.

Possibly. I can also note that the AOA bracket is in different position than in dcs on takeoff roll. The tape's bracket is in middle of -5degrees  while ingame it's quite below -5 degrees.

Edited March 30, 2022 by fapador

[Frederf]

The GC is placed in a fixed location on the HUD, the ZSL. It shouldn't change regardless of alignment, etc. as far as I know anyway.

[Deano87]

13 hours ago, Frederf said:

The GC is placed in a fixed location on the HUD, the ZSL. It shouldn't change regardless of alignment, etc. as far as I know anyway.

Correct, but the horizon line, which is what it was being compared to, will change during an alignment.

And of course will depend if the parking space is sloped in any way etc.

Edited March 31, 2022 by Deano87

[fapador]

16 minutes ago, Deano87 said:

Correct, but the horizon line, which is what it was being compared to, will change during an alignment.

And of course will depend if the parking space is sloped in any way etc.

I dont think the horizon will change in that video because it seems to be pretty close in the correct position if you look the end of the mountain . The tapes though might possibly move upwards with aligment. Also there is no explanation about the AOA bracket as in dcs it seems to be always too low nearly out of hud in dcs. IMO something is off in dcs HUD, but I still cant exactly point to what that is. It just doesn't convince me 100%.

 

EDIT: I just noticed DCS AOA bracket has a tendency to change position even when waiting still on the ground. Perhaps the sensor position changing with wind affects its location on the HUD? as it randomly moves from -10 back up to -5

Edited March 31, 2022 by fapador

[Deano87]

12 minutes ago, fapador said:

Perhaps the sensor position changing with wind affects its location on the HUD?

Yes, it does.

[fapador]

I tried a takeoff roll It still is off, even with speed going through it. It appears not to be modelled correct

Edited March 31, 2022 by fapador

[Deano87]

15 minutes ago, fapador said:

I dont think the horizon will change in that video because it seems to be pretty close in the correct position if you look the end of the mountain .

Look at the trees across the taxiway, the horizon line is up near the top of the trees, the only way that can be correct is if the taxiway in front of the aircraft is a massive down slope, or the undercarriage on that F-16 is 20ft tall. And since most modern airfields are pretty flat, I'm gonna say that line isn't in the correct place yet.

[fapador]

3 minutes ago, Deano87 said:

Look at the trees across the taxiway, the horizon line is up near the top of the trees, the only way that can be correct is if the taxiway in front of the aircraft is a massive down slope, or the undercarriage on that F-16 is 20ft tall. And since most modern airfields are pretty flat, I'm gonna say that line isn't in the correct place yet.

I dunno matte, the line depicts the horizon not the ground. Its  possible with view angle that the horizon is above ground like this picture.

 

 

[Deano87]

17 minutes ago, fapador said:

the line depicts the horizon not the ground. Its  possible with view angle that the horizon is above ground like this picture.

Yes, but that requires a slope in front of the camera, exactly what I said. Military airfields are most of the time pretty flat, if that horizon line is correct than it means there is a 3 degree slope between the hangar that the aircraft is in, and the row of trees. or that the F-16 is 20 feet taller than it should be. Remember, if the horizon line goes through it then the HUD of the jet is at the same elevation as what the horizon line intersects. Neither of these scenarios are sensible, therefor the horizon line isn't in a correct place because the jet hasn't aligned yet.

I agree with you that the gun cross is perhaps in the wrong place compared to the horizon line, But I don't think that video shows it well, because it's clear the jet is still going through the startup process. There are lots of F-16 onboard videos.. Maybe look for some more.

Edited March 31, 2022 by Deano87

[Frederf]

How about a check of the attitude of the airframe taken from the outside? The GC might be correct relative to the ZSL/AD just the airplane is riding nose high.

[fapador]

12 minutes ago, Deano87 said:

Yes, but that requires a slope in front of the camera, exactly what I said. Military airfields are most of the time pretty flat, if that horizon line is correct than it means there is a 5 degree slope between the hangar that the aircraft is in, and the row of trees. or that the F-16 is 20 feet taller than it should be. Remember, if the horizon line goes through it then the HUD of the jet is at the same elevation as what the horizon line intersects. Neither of these scenarios are sensible, therefor the horizon line isn't in a correct place because the jet hasn't aligned yet.

There's also this screenshot  of hud which shows the jet aligning but the horizon line is definitely on the correct position. 

[Deano87]

End of this video shows the gun cross above the horizon line as the jet comes to a stop on the end of the runway. So i dunno.

1 minute ago, fapador said:

There's also this screenshot  of hud which shows the jet aligning but the horizon line is definitely on the correct position. 

Yes and the gun cross is in a different place to your original video. Also depends where in the alignment process it is.

[fapador]

4 minutes ago, Deano87 said:

Yes and the gun cross is in a different place to your original video. Also depends where in the alignment process it is.

on that screenshot I can see it below horizon.

 

4 minutes ago, Deano87 said:

End of this video shows the gun cross above the horizon line as the jet comes to a stop on the end of the runway. So i dunno.

Possibly it has something to do with an empty loaded plane out of fuel, the shock strut moves the plane upwards so the cross goes higher. In DCS no matter what load it is always above .

Edited March 31, 2022 by fapador

[Deano87]

Yes.. Just a tiny bit below the horizon. In that first video you its 2.5 degrees below the horizon, which is excessive imho.

Take a look at some other HUD tapes that are out there and see what you can find. Like I've said before I think a softer nose gear would add a bit more of the characteristic F-16 bobbing on the ground and also bring the gun cross down a bit.

Edited March 31, 2022 by Deano87