About the F-15C HUD view angle, a question to the experts

[Katmandu]

In DCS, only the central portion of the F-15C HUD is visible when we shift the virtual head all the way back, to the seat headrest (Ctrl + Shift + numpad/ ) (this is different to the usual zoom/FOV adjustments) - a normal position for the pilot.  Is this how it is in the real life? Even if one was to shut one of the eyes to counter the the binocular vision? There were some F-15 pilots/techs "Ask Me Anything" topics at some point, wonder if these people are still around...

If the problem is real, it would be nice to address it for the next iteration of FC3 - Modern Air Combat (MAC).

This is in contrast to other planes such as the F-16C, F/A-18C, A/V-8B, Su-27 -all of them provide near full HUD picture with the pilot head fully back, against the headrest (Ctrl + Shift + numpad/ ). 

Spoiler

This problem currently is mitigated in DCS by moving the virtual head towards the HUD (Ctrl+Shift+numpad*), this provides the full view of its indication, but at a cost of ugly optical distortion. Compare the below with the thin undistorted canopy frames of the F/A-18 and Su-27 above. Also, pilots head is now good distance away from the headrest - a strange design decision for an air superiority jet where high g loads are the norm. Also note that, despite different zoom levels, the same area of HUD indication is visible - both vertical scales (Speed and Alt) are in view in the zoomed out AND zoomed in pics. Just to reiterate that the point here is the head position and not zoom.

Edited November 30, 2022 by Katmandu

[razo+r]

54 minutes ago, Katmandu said:

In DCS, only the central portion of the F-15C HUD is visible when we shift the virtual head all the way back, to the seat headrest (Ctrl + Shift + numpad/ )- a normal position for the pilot.  Is this how it is in the real life?

 

 

 

Are you sure that the view in DCS all the way back equals to the same position a human would have, including the part of the head behind the eyes plus the helmet?

Also, look at some videos, the pilot does not rest his head on the headrest for most of the time.

 

Edited November 29, 2022 by razo+r

[Hiob]

You need to take into account a natural head position AND a natural FOV. I don't know for the F-15, because I don't fly it, but in most DCS Aircraft, once you include all view related parameters you get it working.

[Katmandu]

1 hour ago, razo+r said:

Are you sure that the view in DCS all the way back equals to the same position a human would have, including the part of the head behind the eyes plus the helmet?

I've made that allowance in my screenshot, the position is such that when I turn pilots virtual head 90deg, the view does not go flush against the headrest, but is a realistic distance from it. in any case, even adding another extra head width on top  does not address the issue of limited HUD view.

1 hour ago, razo+r said:

look at some videos, the pilot does not rest his head on the headrest for most of the time

A point worth making, but, the plane is made for combat and high g. Then pilot's head is against the headrest and his/her situational awareness would be hampered - as far as the HUD goes. This logic has additional evidence from the other fighters (see their pics above, also with head on the headrest), both US and Russian, which give the pilot a much better HUD picture with head rested against the headrest.

36 minutes ago, Hiob said:

You need to take into account a natural head position AND a natural FOV. I don't know for the F-15, because I don't fly it, but in most DCS Aircraft, once you include all view related parameters you get it working.

Other planes are much better in this regard, see my pics of the F-16, F-18 and Su-27 above. Same parameters - i.e. head against headrest.

Edited November 29, 2022 by Katmandu

[Hiob]

The F-16 doesn't fit either, because your fov is way to big. For a 16:9 Monitor it should be not more than ~80 (depending on your seating position at the desk - 60 is realistic).

Don't get me wrong - FOV is a matter of taste. You can choose whatever you like for flying or you seem fit. BUT fov is affecting such things and you can calculate a "realistic" fov - which is much smaller than most virtual pilots would find useful/comfortable.

Edit: A good way to determine if your camera/head-position is "good/realistic" is to look straight down into you (virtual) crotch. Your eyes should be looking straight at the front edge of the seat - middle perhaps but no further back.

Edited November 29, 2022 by Hiob

[Hiob]

Oh, and btw.... if you find the F-15 HUD troublesome - don't try the A-10!

[Nahen]

I recommend VR goggles, it's as it should be Unless you mess with the settings somehow drastically.

[Katmandu]

19 minutes ago, Hiob said:

The F-16 doesn't fit either, because your fov is way to big. For a 16:9 Monitor it should be not more than ~80 (depending on your seating position at the desk - 60 is realistic).

The F-16 fits almost compltely, it is easy to imagine that once binucular vision is in effect the HUD would be fully visible.

However, I think you are confused by FOV and virtual head position. They are two different things. See below- same head position (away from the headrest), but different  FOV. In both cases the HUD indication coverage is identical in how much indication is visible. Only the size of the indication is larger with the smaller FOV (i.e. zoomed in) second pic. But they both show  HUD speed and altitude scales - unlike the first pic in my original post.

 

[Hiob]

Another - less technical - thing to consider perhaps. In RL your view is less static than in the game (depending if your using VR/TrackIR or not), which makes it easier to move your view and get information on the edges of the HUD. Also, in Dogfight, your eyes should be on the adversary, not glued to the hud. When the bandit is in the gun-funnel, the edges of the HUD don't play much or a role either.

[Katmandu]

37 minutes ago, Nahen said:

I recommend VR goggles, it's as it should be Unless you mess with the settings somehow drastically.

It's been a while since I sold my VR, and it would be an interesting thing to check - how much of the HUD is visible if you press your virtual head back towards the headrest. Could you check it perhaps? Distortion is certainly not an issue in VR, I remember that much from my time with Oculus

Edited November 29, 2022 by Katmandu

[Hiob]

1 minute ago, Katmandu said:

The F-16 fits almost compltely, it is easy to imagine that once binucular vision is in effect the HUD would be fully visible.

However, I think you are confused by FOV and virtual head position. They are two different things. See below- same head position (away from the headrest), but different  FOV. In both cases the HUD indication coverage is identical in how much indication is visible. Only the size of the indication is larger with the smaller FOV (i.e. zoomed in) second pic. But they both show  HUD speed and altitude scales - unlike the first pic in my original post.

 

Yes, you're right. FOV enlarges the whole picture not only the HUD. Head position is more relevant here. 
But it all comes together for finding a view position, that feels "right".

By the way, you mentioned an important thing here. Binucular vision. Perhaps that's the core problem here. I remember that the A-10 in VR also had less of a problem with the HUD view...

[razo+r]

31 minutes ago, Katmandu said:

A point worth making, but, the plane is made for combat and high g. Then pilot's head is against the headrest and his/her situational awareness would be hampered - as far as the HUD goes. This logic has additional evidence from the other fighters (see their pics above, also with head on the headrest), both US and Russian, which give the pilot a much better HUD picture.

It is designed to withstand high G, but you will not find yourself flying high G maneuvers most of them time. Compared to the whole flight, you spend very little time in a high G period of flight.

What's also interesting to see, compare the pics of other jets you posted. Look how narrow the one from the F-15 is compared to the others. Probably is also playing a big role, how big the HUD itself is.

31 minutes ago, Katmandu said:

Other planes are much better in this regard, see my pics of the F-16, F-18 and Su-27 above. Same parameters - i.e. head against headrest.

 

There are also some that are worse, the A-10 for example being the most prominent one.

[Katmandu]

6 minutes ago, Hiob said:

But it all comes together for finding a view position, that feels "right".

Logically, and looking at the other fighters in my first post pics, the head on the headrest position must feel right, as that's where the important stuff happens.

 

6 minutes ago, Hiob said:

Binucular vision. Perhaps that's the core problem here. I remember that the A-10

This could be the answer, I do not have a VR set to check atm. The way to test in VR would be to move the virtual head towards the headrest (CTRL+ Shift+numpad/) , check the HUD coverage, then close one eye and check the HUD coverage once more.

The A-10 potentially may have a different design philosophy as it's not a fighter, less need to be on the headrest. But it is also an earlier DCS module, so it may share a bug with the F-15... 

Edited November 29, 2022 by Katmandu

[razo+r]

4 minutes ago, Katmandu said:

The A-10 potentially may have a different design philosophy as it's not a fighter, less need to be on the headrest. But it is also an earlier DCS module, so it may share a bug with the F-15... 

 

Check the A-10C2 then, it's a lot newer than the F-15, and when it got released many people who don't use VR asked about the head position of it.

Edited November 29, 2022 by razo+r

[Katmandu]

9 minutes ago, razo+r said:

It is designed to withstand high G, but you will not find yourself flying high G maneuvers most of them time. Compared to the whole flight, you spend very little time in a high G period of flight.

Yes, but as I said above, the little time pilot spends doing high g with the head back on the headrest is also the time when he/she needs the absolute maximum SA.

11 minutes ago, razo+r said:

compare the pics of other jets you posted. Look how narrow the one from the F-15 is compared to the others. Probably is also playing a big role, how big the HUD itself is.

To me the F-16 HUD appears very similar size wise because I understand the F-15 cockpit to be much roomier. Su-27 HUD is also very similar in size to the F-15. FA-18 is flared, so hard to say, but also similar - to my eyes, again. Would be curious to see their actual dimensions.

 

5 minutes ago, razo+r said:

Check the A-10C2 then, it's a lot newer than the F-15, and when it got released many people who don't use VR asked about the head position of it.

I should do. But the nagging doubts would still not go away - ED did not make it from scratch, mistakes could have carried over, different philosophy as not a fighter...

[razo+r]

24 minutes ago, Katmandu said:

Yes, but as I said above, the little time pilot spends doing high g with the head back on the headrest is also the time when he/she needs the absolute maximum SA.

If you check some cockpit videos, you'll see very few do rest their head on the headrest. Doing so would most likely even reduce your SA, not maximising it.

 

 

 

[Nahen]

3 hours ago, Katmandu said:

It's been a while since I sold my VR, and it would be an interesting thing to check - how much of the HUD is visible if you press your virtual head back towards the headrest. Could you check it perhaps? Distortion is certainly not an issue in VR, I remember that much from my time with Oculus

 

If my sons let me take the goggles from them I was flying a while ago and I remember that the HUD - its behavior and visibility from different angles and distances were completely different than what is on the monitor with trackIR. I'll try to capture the goggles tomorrow
I already told one of my sons about it today but somehow he tactically "forgot"

[draconus]

The default head position is the right one and correct - most common for the pilot - the headrest is not the place to keep the head all the time. By moving the head back you lose angles down the nose. These are convenient for taxi and landing but also helpful at high alpha gun shots.

The HUD is calibrated for that one exact eyes position so it's normal that it's not right if you move your head elsewhere. In VR it's the same position - closing one eye you'll just see the HUD picture shifted to one side. If you move the head back your HUD picture will not fit in the frame - same as on monitor. Why would you expect anything different?

You can fly and set it as you wish but there's no bug here. Imho you're chasing ghosts after some false assumptions.

Edited November 29, 2022 by draconus

[Katmandu]

Here it is from a real fighter pilot: "The idea when you pull G's is you set your head on the headrest... because the helmet with cueing systems weigh 15 pounds times 9, when you get that, you're talking over 100 pounds of force, and you try to pick it off the seat ... you can tear tendons- which I did, that's what happened to me..."

@16:00

Secondly, if the entire HUD picture is visible and you move your head towards the HUD, you are not losing any of that picture. So, if we are talking about logic, then it seems logical to set up the HUD picture for the furthest point - the headrest. As one moves closer, all of the HUD info is still there and nothing is lost. 

As is the case in the F-16, Su-27 etc - see my very first post.

1 hour ago, draconus said:

the headrest is not the place to keep the head all the time. By moving the head back you lose angles down the nose. These are convenient for taxi and landing but also helpful at high alpha gun shots.

All the time - certainly not, but why design a HUD to lose info during some brief, yet common and crucially important seconds when the headrest IS used?

2 hours ago, Nahen said:

he HUD - its behavior and visibility from different angles and distances were completely different than what is on the monitor with trackIR. I'll try to capture the goggles tomorrow

Thanks for that! I know exactly what you mean as I also flew with VR a couple of years back  Please remmber to move your virtual head back with (Ctrl + Shift + numpad/ ) (this is different to the usual zoom/FOV adjustments) as this is the crux of the matter  

Edited November 29, 2022 by Katmandu

[razo+r]

10 minutes ago, Katmandu said:

Here it is from a real fighter pilot: "The idea when you pull G's is you set your head on the headrest... because the helmet with cuing systems weigh 15 pounds times 9, when you get that, you're talking over 100 pounds of force, and you try to pick it off the seat ... you can tear tendons- which I did, that's what happened to me..."

@16:00

I like how he says that and shows footage of him not resting his head on the headrest during maneuvering. 

10 minutes ago, Katmandu said:

Secondly, if the entire HUD picture is visible and you move your head towards the HUD, you are not losing any of that picture. So, if we are talking about logic, then it seems logical to set up picture for the furthest point - the headrest. As one moves closer, the HUD is still there and nothing is lost. 

As is the case in the F-16, Su-27 etc - see my very first post.

The most logical decision is to calibrate the HUD to the position in which the pilot will be for most of the flight, which is not all the way back. 

This is also the case for the other aircraft you've shown. Both F-16 and F-18 also show this, as part of the HUD is cut off when you are all the way back. 

10 minutes ago, Katmandu said:

All the time - certainly not, but why design a HUD to lose info during some brief, yet common and crucially important seconds when the headrest IS used?

 [...] 

Probably because you spend so little time in those cases, it might not be worth it to do that. Besides, most "lost" info can be obtained by looking slightly lower into the cockpit... 

[Katmandu]

1 hour ago, draconus said:

Imho you're chasing ghosts after some false assumptions.

I'll restate my motivation just in case. The current options for TrackIR F-15C fliers are:

1. Make do with the mostly truncated HUD when at seat rest of the F-15, but with good looking non distorted canopy frame.

2. Enjoy the full HUD, but with distorted canopy frame.

Of course, if the HUD setting is correct, then I am NOT suggesting to reset it to please the TrackIR users! but, if it is not correct and should be more like the F-16 etc, then this conversation is not splitting hairs about a purely academic matter, but has practical benefits - if it's a bug and if it's corrected.

Edited November 29, 2022 by Katmandu

[Katmandu]

12 minutes ago, razo+r said:

I like how he says that and shows footage of him not resting his head on the headrest during maneuvering. 

I know  Just thinking logically again, perhaps the G's in the videos where not as hard or not as prolonged. Plus fresh pilots, less fatigue etc. 

12 minutes ago, razo+r said:

This is also the case for the other aircraft you've shown. Both F-16 and F-18 also show this, as part of the HUD is cut off when you are all the way back. 

A lot lot less is cut off though, just compare the F-16 pic with the first F-15 pic. With binocular vision there would be no cut off at all with the F-16.

 

12 minutes ago, razo+r said:

The most logical decision is to calibrate the HUD to the position in which the pilot will be for most of the flight, which is not all the way back. 

But again, the pilot doesn't not lose HUD info in the F-16 - not when he is at head rest, not when he's moved his head forwards (win-win). Full picture always. With what you are proposing, the picture is full when in normal cruise mode, but truncated when at headrest (win-lose).

Edited November 29, 2022 by Katmandu

[razo+r]

5 minutes ago, Katmandu said:

But again, the pilot doesn't not lose HUD info in the F-16 - not when he is at head rest, not when he's moved his head forwards (win-win). Full picture always. With what you are proposing, the picture is full when in normal cruise mode, but truncated when at headrest (win-lose).

 

Project the DED onto the HUD and tell me again if you dont lose any info in the F-16 or not. 

Think about your proposition for a second. If calibrated for the position all the way back, it means you are "wasting" space for all the time except in the few minutes at most per flight when he has the head on the headrest. You will have to use a smaller font, making it possibly harder to decypher numbers and text. Or you have to cramp the symbology together and make it less clear to see infos. 

[Katmandu]

2 minutes ago, razo+r said:

If calibrated for the position all the way back, it means you are "wasting" space for all the time except in the few minutes at most per flight when he has the head on the headrest. You will have to use a smaller font, making it possibly harder to decypher numbers and text.

That's a fair point  But so is mine  These are all compromises, including the DED projection's (Bingo fuel flow numbers used for refuel etc? Correct me if I'm wrong, I've not flown the 16 for a while). So the F-16's design compromise was to include the air combat essential info at all seating positions, and other info for other positions - my interpretation. maybe the F-15's compromises were thought about differently of course, but would be good to know.

[TheFreshPrince]

vor 15 Stunden schrieb razo+r:

I like how he says that and shows footage of him not resting his head on the headrest during maneuvering.

Looks like a Hornet in the video and he says later on in the video that the Hornet can pull 7.5G max. So I guess it's possible to still move your head around at 7G if you're trained.