FPM HUD Limit

[SCU]

Hello folks.

I was watching a couple of video of an F-15 HUD recording, and while I know that the F-15 in DCS is not a full fidelity model, but I couldn't help but notice that the actual F-15 in the videos have a lower FPM (Flight Path Marker / Velocity Vector) limitation in the HUD.. I always thought the FPM getting HUD limited too early when landing the Eagle in DCS to be a little quirky, and from the videos of the actual jet I saw, it looks like the FPM modeled in-game gets limited a little bit 'earlier' than what is supposed to be, if you get my drift.

 

If that is the case, isn't it worth tweaking it in-game? How much work would it take to change the lower limit for the VV? Can a tweak like this affect other systems in the model? Cheers :thumbup:.

[GGTharos]

I've never had an issue with the FPM during landing - I'm all for accuracy but this doesn't seem like a reason for tweaking.

 

Can you point to those videos?

[SCU]

Was just in the process of typing this as you replied GG^

 

I played a little bit with Photoshop to figure out what's the approximate difference between the FPM limit in reality and the one in-game and attached below is what I got so far. Note that these images are just food for thought and are not intended to be an accurate representation of how it's supposed to be in-game; I'm just trying to make a comparison.

 

 

First image is from:

Second image:

Third image:

Fourth image:

(The 1st shot got me baffled when I looked at it in PS, I noticed the pitch ladder changes its increments after the 30 degrees mark, where it increases in 10's, while keeping the same distances!!, instead of the normal 5 increments that were the case from 0 to 30, and from 0 to 90 in every other jet HUD I've seen.. It's how it's modeled in-game as well! It's probably my poor understanding of how pitch ladder scales work or something ;))

 

 

I know I probably made mistakes in my assumption, so I'd like to know what other players might think of this, and maybe if I'm lucky someone who actually works on the model who has some actual info.

Any thoughts?

Edited February 9, 2018 by SCU

[GGTharos]

Ok, it's a HUD line-up issue ... don't know how much effort they want to put into correcting this.

The pitch ladder in-game is correct though, actually moving where it is would alter its meaning.

[SCU]

The pitch ladder in-game is correct though, actually moving where it is would alter its meaning.

No no, I didn't say anything about altering the pitch ladder; what I wrote in parenthesis was just me expressing my confusion about the markings on the real F-15 pitch ladder, they increment in a really weird way that I don't understand.

 

I noticed this as I was using the ruler tool to get the length between two pitch ladder 'rungs' in the black & white image (first one I linked); the markings increment by 10 starting from the 30 degree marking, it basically goes like this: 0 (Horizon), 5, 10, 15, 20, 25, 30, 40, 50, 60... and so on, and that goes both ways: above & below the horizon. It's modeled in DCS in the same way as well.

[SCU]

As I said that I did some mistakes as I did those images hastily, in the last image I shouldn't have said to move the 20 degree pitch rung below, it should stay at the same place as it represents the current location of this degree... What I was really trying to illustrate there was what it would be like if the VV was HUD limited at its real location along with its pitch rung, just to show what it might have looked like, you know? But yeah, it's absolutely wrong to have those red pitch ladders there!1

[GGTharos]

I don't know what to say - I mean the HuD representation depends on your distance to the hud itself to begin with - it may fill the HuD or it may not :)

If anything is wrong, it's the upper potion - it may need to be shifted up.

[SCU]

the HuD representation depends on your distance to the hud itself to begin with - it may fill the HuD or it may not :)

 

True, but remember that HUDs are projected so that they seem that they're at infinity, so I think that should mean that it doesn't matter how far or close you are to it in the cockpit, it would always look the same size.

 

If anything is wrong, it's the upper potion - it may need to be shifted up.

Hmm, it's an interesting hypothesis but I don't see anything that might indicate that the upper info are mis-located; remember it is all in reference to the Jet's waterline, which is supposedly fixed and accurately modeled & there's nothing to indicate that any of that is wrongly implemented.

 

IMO the only thing that's wrong in the HUD is the VV's lower limit, otherwise it's an almost spot on HUD as the real thing, only a couple other things maybe are wrong, but I can't confirm, which includes: the HUD info should go down a bit with landing configuration when gear goes down (which would be pretty cool if implemented), and like other really minor unnoticeable stuff, perhaps.

[SCU]

The problem with your comparison screenshots is that the RW picture doesn't show the HUD structure and hence we don't know where exactly the projection is on the HUD.

I don't exactly get what you mean by that. If you mean that we don't know where the VV is on the HUD in the videos when it's HUD limited, well in the stall test video the whole HUD projection is shown, including the VV limit point, but in the DACT air to air video (black & white one), the VV's limit is not shown but in a 90° bank it can be clearly deduced by looking at the pitch ladder being limited (because it's caged to the also limited VV).

 

See attached image; in both images the FPM is HUD limited, but notice the different distances between the pitch ladder and the lower left info block, in the RL image & the in-game image.

 

In DCS, when the VV is limited and you're in a 90° bank, the pitch ladder markings nearly touches the lower left info block. While in real life, with the same previous conditions, the pitch ladder markers are lower by about 2.5° than in DCS, and hence the VV has a lower limit by about the same distance.

Edited February 9, 2018 by SCU