G-Forces modeling please fix

[Kat00m]

Hi Guys,

 

I've been flying for about 2 weeks and it's been fun getting back into it.  I flew Il-2/fb/PF/46 for 12 years and some of it competitive matches.  I'm happy to be back.  I only fly online with expert settings and on the combat box server.

 

I'm sure this has been discussed but I have to let this out.  What is going on the the gforce recovery? Nothing makes sense.  2 maybe 3  g's on the deck and I almost had a solution on a Dora (I was in a tempest) and I black out ... never to recover after 7 seconds of black out and a relaxed stick?  Really?  I was in the same turning circle with same speed.  One of many examples of black outs and hitting the ground.  This was early in the sortie and literally no fatigue.  It's very frustrating and this was not an issue with the original Il-2.  Back then maybe 5-6 g's before early blackout with a much more realistic recovery.  Why are we modeling student pilots with no G endurance?  I notice the problem much more on the allies side.  The recovery seems slightly faster in the axis planes but still not done right.  I'm sorry to complain about this I am not a person to complain about anything but this does not make the experience fun and/or realistic.  No recovery should be 5-10 seconds long not even at 8 or 9 g's.  Most fights are in the weeds and we need faster recovery time everyone is lawn darting and it ruins the gameplay.  Oleg had it right the first time around try to match that or get close.  I think fatigue is fine to model but up the g tolerance please and also recovery time after the stick is relaxed to center is down right ridiculous.  Sorry for the rant but everyone on my chat saw what happen and we all agree it needs to be made more realistic to simulate experienced pilots not flight school noobs who can't pull 3 g's.  Other then this I think the new generation Il-2 in on point.

Edited June 10, 2020 by Gate

[JG27*PapaFly]

2 hours ago, Gate said:

Back then maybe 5-6 g's before early blackout with a much more realistic recovery.  W

I'm sorry to disappoint you, but G-LOC recovery is much more realistic here than in the old game, which I, too, flew extensively for 13 years. As a biology/biochemistry PhD, I have great interest in the topic, and have read many of the relevant research papers.

 

G-LOC entry and duration are inherently unpredictable in reality. Speed control, g onset rate  control, and fatigue are the main factors to look for when it comes to avoiding a sudden G-LOC. In reality, recovery often takes 30 seconds or more, and is incomplete for several minutes, during which pilots experience not only fatigue, but also spatiotemporal orientation difficulties. This means that, IRL pilots are severely incapacitated for several minutes after a G-LOC, and would rtb ASAP. G-LOCs are extremely serious events and continue to kill pilots.

[HR_Tumu]

G Effects are great adition for game

 

But i agree, are some things can be tunned.  

 

For me will be great if i can understand how it works.... because really i cant understand except if i accept first this simple rule.... axis pilots have better tolerance... and i allways thinked the tolerance for all pilots was the same... .

 

On theory are the same or not ? 

 

 

[Floppy_Sock]

@JG27_PapaFly

 

While the duration of the blackouts is probably somewhat correct, I find that modern models of +Gz tolerance do not match up with what we have in the game.

 

First, the most dangerous maneuver one can do as a pilot is a push pull. It is generally the biggest killer of pilots due to GLOC. Note that this is not simply due to a bunt followed by a pull, but also aircraft with high roll rates can induce substantial negative G forces due to the radial acceleration. Even very short exposures to -Gz can substantially reduce +Gz. This effect is not modeled in the game at all and it contributes to the multiplayer meta of oscillating between bunts and pulls to avoid GLOC. 

 

Second, G onset rate is not as important as the devs make it out to be. That theory is outdated and has been readily disproven in the literature. See the following paper for the full details - I’m just going to pull a few figures and a section of the abstract to illustrate. 

 

Paper url: https://link.springer.com/article/10.1186/2046-7648-2-19

 

First, the most comprehensive collection of GLOC incidents as a function of onset rate:

Notice that after 1g/s onset rate is irrelevant. The physiological explanation is in the paper if you’re interested.

 

Furthermore, a comparison of the model used in IL2 GB was authored by Stoll(depicted below by the red curve), compared to the modern model (depicted by the blue curve)

Note that the biggest reason for this discrepancy is that the red curve is an extrapolation from 14 gloc incidents. The blue curve is an average of over 800 incidents.

 

Two big things can be gleaned from this study:

1. Above 1G/s - onset rate does not matter.

2. For any rapid onset rate pull, mean duration until GLOC is long - slightly above 9 seconds in the average.

 

As a comparison, here’s a fresh pilot in a spit mk9 during a max performing horizontal break turn:

I recorded this using the motion simulator output - this is the same data that is depicted on the in game G-meter. This is pretty steady 2G/s onset rate. A pretty measly 3.7 seconds to gloc. That’s pretty far off form the 9.1g seconds it should be.

 

It should be noted, that this is also the absolute minimum of human tolerance since this is data collected during pilot training. This data did not come from a study conducted to find the true average time to GLOC. From the methods section we know 

Quote

The data from the centrifuge repository contained 888 G-LOC episodes spanning the years 1978 to 1992, generated from centrifuge exposures at the USAF School of Aerospace Medicine, Brooks AFB, Texas and the Naval Air Warfare Center, Warminster, Pennsylvania. The repository did not identify the individual experiencing the G-LOC episode; therefore, the total number of individual subjects was approximately 723. There were 585 individuals having 1 G-LOC episode (585 episodes), 111 subjects experiencing two G-LOC episodes (222 epi- sodes), and 27 experiencing three episodes (81 episodes), for a total of 888 G-LOC episodes.

But we do now know how many total recruits have passed through these tests. I know for a fact that one of the samples used in these tests showed GLOC for somewhere between 5-30% of the recruits lost consciousness depending on the onset rate. Interestingly, the gradual onset rate test (.1g/s if I remember correctly) actually induced the most GLOC episodes due to the duration of the test. Students performed much better in the rapid onset rate tests. I can dig that data up if you’re interested. Thus, it’s safe to say that this curve is invariably skewed low. 

 

Let me conclude with a excerpt from the abstract of the paper above - please note the final sentence:

 

Quote

The two new G-LOC curves differed significantly from previous curves in temporal characteristics and key aspects underlying neurologic response to acceleration. The new acceleration onset rate curve reveals that for onset rates ≥ 1.0 G/s, G-LOC will occur in a mean time of 9.10 s and is independent of the onset rate. The new +Gz-level curve demonstrates that G-LOC will occur in a mean time of 9.65 s for rapid onset rate exposures to +Gz levels ≥ +7 Gz. The minimum +Gz-level threshold tolerance was defined as +4.7 Gz. When +Gz onset rates are gradual, ≤ 0.2 G/s, G-LOC occurs in a mean time of 74.41 s. G-LOC did not occur earlier than 5 s for any acceleration exposure.

 

 

 

 

Edited June 10, 2020 by Floppy_Sock

[Kat00m]

8 hours ago, JG27_PapaFly said:

In reality, recovery often takes 30 seconds or more, and is incomplete for several minutes, during which pilots experience not only fatigue, but also spatiotemporal orientation difficulties. This means that, IRL pilots are severely incapacitated for several minutes after a G-LOC, and would rtb ASAP. G-LOCs are extremely serious events and continue to kill pilots.

Well then explain Red Bull air racing where the pilots sustain 6-9g's with no blackouts.   I think they need to model the pilots closer to the 51 pilot that has the g suit on (which is manageable and recovery seems much better) then give the extra 1g on top of that to the 51 pilot.  In sustained turns I manage to avoid the black out but if I match the axis pilot that does the same speed and turn rate he's fine and I black out never to recover in time.  Both sides should be modeled the same (unless you have a G-suit on of course)

[[DBS]Browning]

You will find you can pull 6-9 g in the P-51 for a similar duration to those levels in air racing.

 

You will also find that when following another aircraft, you will pull more g than him in pure or lead persuit.

[Floppy_Sock]

@[DBS]Browning Yes, you reach the same peak accelerations, but the pilot cannot tolerate these same jerk (Rate of change of acceleration - in case you’re unfamiliar) that an air racer does - which is the more important point.

 

When they that loop which peaks at around 10G, they’re sustaining onset rates in greater than 7G/s. That is largely an irrelevant comparison since I don’t think those heavy warbirds loaded with guns, ammo, and fuel can load that fast anyway. The break turn chart I showed above is a lowly 2G/s.

 

And it’s not that they’re super humans, it’s that the model is simply wrong. The physiological argument is as follows: the brain cells enter a state of self preservation (which induces LOC) after about 9 seconds of ischemia (lack of blood flow). Within that period, the cells are consuming their stored oxygen and still functioning. There is data to show in other papers that hypoxia related symptoms appear earlier than the 9 seconds leading to a short bout of confusion before LOC but that’s another discussion. (It’s quite an interesting read - they put people in a centrifuge and told them to do math problems until they blacked out - the performance declined substantially a few seconds before LOC).

 

The tail section of the tolerance curve - aka what happens after 9 seconds is actually what needs to be discussed. In some tests, it’s found that for subject without a g suit and no agsm experience, the tail of that curve is quite low (about 4g). But again this is after the 9 second transient stage where pretty much any g load is tolerated. 

 

 

Edited June 10, 2020 by Floppy_Sock

[LLv24_Zami]

9 hours ago, HRc_Tumu said:

G Effects are great adition for game

 

But i agree, are some things can be tunned.  

 

For me will be great if i can understand how it works.... because really i cant understand except if i accept first this simple rule.... axis pilots have better tolerance... and i allways thinked the tolerance for all pilots was the same... .

 

On theory are the same or not ? 

 

 

Hi Tumu!

 

All pilots have same G tolerance, expect for a few American planes. They have +1G for their G-suits. That is the information we have

[JG27*PapaFly]

4 hours ago, Floppy_Sock said:

@JG27_PapaFly

 

While the duration of the blackouts is probably somewhat correct, I find that modern models of +Gz tolerance do not match up with what we have in the game.

 

First, the most dangerous maneuver one can do as a pilot is a push pull. It is generally the biggest killer of pilots due to GLOC. Note that this is not simply due to a bunt followed by a pull, but also aircraft with high roll rates can induce substantial negative G forces due to the radial acceleration. Even very short exposures to -Gz can substantially reduce +Gz. This effect is not modeled in the game at all and it contributes to the multiplayer meta of oscillating between bunts and pulls to avoid GLOC. 

 

Second, G onset rate is not as important as the devs make it out to be. That theory is outdated and has been readily disproven in the literature. See the following paper for the full details - I’m just going to pull a few figures and a section of the abstract to illustrate. 

 

Paper url: https://link.springer.com/article/10.1186/2046-7648-2-19

Hi there Sock. I'm not saying the game is perfect, but IMO it is by far the best physiology model we've seen in a flightsim.

 

I agree that the functional buffer period should be longer, and that push-pull tolerance should be decreased. But there are also a couple of points in that paper that should be taken with a grain of salt. For one, the dataset is a mixed bag containing all sorts of different experiments: with and without AGSM, with and without g-suits etc. The data should be stratified according to the different experimental conditions as well as subject skill levels and, perhaps even physiological parameters such as body height, bmi, cardiovascular parameters. Many of the subjects were trained airmen, and I'd assume that they performed the standard AGSM. During WWII, AGSM was in it's infancy, and I believe it is safe to assume that the vast majority of WWII airmen did not perform proper AGSM. Same goes for the g-suits which were used back then.

 

And there is one more, fundamental difference between what we experience in game and the published experimental results: the tests were performed in centrifuges, under "sterile" conditions. Subjects were not subjected to the rigors of air combat, but to very controlled experimental conditons. Air combat brings a lot of unknowns to the table: pilots had to use a lot of force in order to move the control surfaces, while at the same time contracting their abdominal and lower body muscles to the maximum in order to limit cerebral blood pressure decrease. We can't really imagine what happens to our G tolerance when we apply stick forces of 50 kg while maximally contracting all lower body muscles. How long will the FBP be after a 3-minute balls-to-the-wall dogfight in a WWII warbird?

[[DBS]Browning]

2 hours ago, Floppy_Sock said:

@[DBS]Browning Yes, you reach the same peak accelerations, but the pilot cannot tolerate these same jerk (Rate of change of acceleration - in case you’re unfamiliar) that an air racer does - which is the more important point.

 

When they that loop which peaks at around 10G, they’re sustaining onset rates in greater than 7G/s. That is largely an irrelevant comparison since I don’t think those heavy warbirds loaded with guns, ammo, and fuel can load that fast anyway. The break turn chart I showed above is a lowly 2G/s.

 

And it’s not that they’re super humans, it’s that the model is simply wrong. The physiological argument is as follows: the brain cells enter a state of self preservation (which induces LOC) after about 9 seconds of ischemia (lack of blood flow). Within that period, the cells are consuming their stored oxygen and still functioning. There is data to show in other papers that hypoxia related symptoms appear earlier than the 9 seconds leading to a short bout of confusion before LOC but that’s another discussion. (It’s quite an interesting read - they put people in a centrifuge and told them to do math problems until they blacked out - the performance declined substantially a few seconds before LOC).

 

The tail section of the tolerance curve - aka what happens after 9 seconds is actually what needs to be discussed. In some tests, it’s found that for subject without a g suit and no agsm experience, the tail of that curve is quite low (about 4g). But again this is after the 9 second transient stage where pretty much any g load is tolerated.

 

It would really strengthen your argument if you could come up with some firm numbers.

A g over time chart achieved in real life that can't be replicated in game would be ideal.

[Floppy_Sock]

@[DBS]Browning 

This is the curve that the paper has come up with. I would recommend that pilots without a g-suit would follow the lowest or second lowest horizontal tails.

 

A g suit will improve the performance in the tail. 

 

@JG27_PapaFly Yes, you’re correct that different data sets were included in the test. However, that is precisely what makes this test so valuable. It shows that regardless of agsm/g suit/ onset rate - the FBP remains constant. The way I understand it at this point is as follows:

1. GLOC is clearly a function of the lack of oxygenation of the brain. 

 

2. The body adapts (slowly) to changes in blood pressure in the brain. This vascular response is what the devs talked about in their original article. The body will naturally raise the blood pressure when exposed to +Gz and conversely, lower it when exposed to -Gz. 

 

3. All external methods to prevent/delay GLOC, namely, any form of AGSM, g-suits, and seat angle, work to increase cerebral BP or reduce the reduction in cerebral BP due to acceleration. AGSM can range from straining to the modern “hick” (which is actually a modified version of the “H1” which substitutes holding your breath with screaming against a partially closed glottis). The effect these factors have on the curveis depicted by the different tails in figure 3.a above.

 

4. For any choice of prevention method or combination thereof, there always exists a +Gz which will be sufficiently large such that the entire combination of prevention methods + natural cardiovascular response will not be sufficient deliver blood to the brain. From the results published by Whinnery, we can conclude that this functional buffer period (FBP) is constant.  If this were not the case, then there clearly should not be such a well defined vertical asymptote in the data. 

 

5. Fatigue during maneuvering comes predominantly from the isometric contractions involved in AGSM, and from stick forces in warbirds.  I only have a single data point for the rate of fatigue during AGSM but a us military study claims that fatigue is on the order of 1g/20sec.  I think one can come up with much better models for this. There is good published data for fatigue, or the diminishing of force output during isometric contraction that can extrapolated here.

 

Indulge me for a minute and tell me what you think of the following. A proper physiological model for g tolerance should best be expressed as a function of cerebral blood pressure. 

 

The two primary systems which are affected by +Gz acceleration are the eye and brain (obviously).

 

One can characterize the vision loss as a function of cranial blood pressure - a quick glance at Wikipedia says vision symptoms show up at around 10-20mmHg BP.

Similar characterizations for consciousness can be derived from the curve above. There’s a source for this in Whinnery’s paper. But right off the bat we can say that if BP in the brain is zero - or effectively zero, GLOC will occur after 9 seconds. 

 

The model for both visual and consciousness can be expressed in terms of the stored oxygen supply in the brain and ocular tissue. 

 

(Read this as an equation, just written vertically)

Oxygen stored in the brain tissue at next simulation step 

= 

Oxygen stored in the brain tissue at current simulation step

+

Oxygen added as a function of BP

- 

A constant consumption rate by the cell (this is chosen so that if no oxygen is added, the pilot should be out in 9 seconds)

 

We can write a function for cranial blood pressure as follows:

Cranial PB

= 

BP from the heart (this term contains the transient cardiovascular response to acceleration - raising BP when exposed to +Gz and lowering it when exposed to -Gz)

+

BP from AGSM (This term depends on pilot fatigue and wounds) 

+ 

BP from g-suit (this can just be a fixed value for simplicity)

-

BP due to acceleration (lets assume no hemodynamics for simplicity, I.e. acceleration affects the cranial BP instantaneously)

 

The only two terms which have dynamics are the fatigue model and the cardiovascular response - it’s probably more than reasonable to fit them with some first order transients to keep the model simple. The fatigue model can take into account things like stick forces too which the sim already has. It could enter without any additional work to add to model fidelity. 

 

Something like this is brutally easy to code - first order discrete systems are just summations at every simulation step.

 

This does a couple things. It introduces two time scales. Fatigue operating on the order of minutes and tissue oxygenation which operates on the order of seconds. 

Currently, I think there only exists one time scale. As such, when your pilot gets “exhausted” he can hardly sustain any g. However, the recovery timescale is on the order of minutes even for a very short exertion.

 

By separating the dynamics into two time scales, you get more aggressive short term dynamics. Since tissue oxygenation now operates on the order of 10’s of seconds in both exhaustion and recovery, it prevents players from pulling excessively long and aggressive maneuvers since the threshold for gloc decreases rapidly after the FBP. However it doesn’t require you to get a new pilot or take an extended break after a few aggressive maneuvers. 

 

Tissue oxygen level will recover with sufficiently low +Gz or a full unload quite quickly. However, since the recovery of ocular / cerebral tissue from oxygen deficit is now not a direct function of G, this crazy bunting to reset your g-tolerance won’t work anymore. Furthermore, this model still rewards pilots for loading gently in a similar way without hamstringing abrupt maneuvers which are necessary when defending. Tissue oxygen level has to be managed to prevent GLOC from one maneuver to the other, but when tying multiple maneuvers together, you now eat into physical fatigue. This recovery is much longer. While your pilot is physically exhausted, long drawn out maneuvers such as scissors, defensive spirals against a fresh pilot will leave you outclassed. Yet, you still are able to perform short aggressive maneuvers such as break turns which do not exceed the FBP.

 

Edited June 11, 2020 by Floppy_Sock

[HR_Tumu]

Thx Zami.

I imagine pilots must have same tolerance.  Thx For confirmation.

 

Then is the "magic" of german tech... planes pulling more gs than you, and pilots with same tolerance no go black out....

 

Because this is the point ;

 

13 hours ago, [DBS]Browning said:

You will also find that when following another aircraft, you will pull more g than him in pure or lead persuit.

 

Thats mean... if im flying on my yak .... fast.... and i see a Enemy diving into me from adove.... he comes more fast than me no? in other case he never catch me.

 

ok,  because if i do a instant turn i go to sleep for sure.... i start carefull a slight turn... until grey vision.... i can see rear me, the enemy pass too fast and  he needs decelarate  , and need pull more stick for have a aim solution... 

if im practicaly on black-out , is logical i can imagine , the enemy  is worst than me ( he come more fast and need more gs to close turn )....so what i find is ... enemy manage to do more heavy turn, aim me... and of course after hand grenade shot , shot down me.....     

 

I dont understand nothing... " Die Gloke Tech" ??

 

On true , debate nothing here, no have sense,  all statments based on feelings are demonized... and i cant agree with this filosophy. Many times this "feelings" are a direct result of internal knowledge . 

 

The feel i have ," german pilots have better tolerance", is result of my observations and result of the logical i learned along the time.  

 And i cant uderstand i both have same tolerance, how this things can happen.

 

 

 

[LLv24_Zami]

36 minutes ago, HRc_Tumu said:

Thx Zami.

I imagine pilots must have same tolerance.  Thx For confirmation.

 

Then is the "magic" of german tech... planes pulling more gs than you, and pilots with same tolerance no go black out....

 

Because this is the point ;

 

 

Thats mean... if im flying on my yak .... fast.... and i see a Enemy diving into me from adove.... he comes more fast than me no? in other case he never catch me.

 

ok,  because if i do a instant turn i go to sleep for sure.... i start carefull a slight turn... until grey vision.... i can see rear me, the enemy pass too fast and  he needs decelarate  , and need pull more stick for have a aim solution... 

if im practicaly on black-out , is logical i can imagine , the enemy  is worst than me ( he come more fast and need more gs to close turn )....so what i find is ... enemy manage to do more heavy turn, aim me... and of course after hand grenade shot , shot down me.....     

 

I dont understand nothing... " Die Gloke Tech" ??

 

On true , debate nothing here, no have sense,  all statments based on feelings are demonized... and i cant agree with this filosophy. Many times this "feelings" are a direct result of internal knowledge . 

 

The feel i have ," german pilots have better tolerance", is result of my observations and result of the logical i learned along the time.  

 And i cant uderstand i both have same tolerance, how this things can happen.

 

 

 

Little clarification, when I said all pilots have the same tolerance expect the ones using planes with G-suit, I meant that the G-suit is the only one that gives the difference. There`s no German tech advantage in the game in my knowledge. And in my observation the only thing giving the difference is G-suit and German planes are not equipped with it. But feelings can differ and that`s fine

Edited June 11, 2020 by LLv24_Zami

[CUJO_1970]

The US Navy concluded that the FW190 seating position along with raised feet/leg position did in fact increase G tolerance.

[LLv24_Zami]

21 minutes ago, CUJO_1970 said:

The US Navy concluded that the FW190 seating position along with raised feet/leg position did in fact increase G tolerance.

Yes, but it`s not modeled currently in the game. 

[JG27*PapaFly]

On 6/11/2020 at 2:36 AM, Floppy_Sock said:

A proper physiological model for g tolerance should best be expressed as a function of cerebral blood pressure.

That would make a lot of sense IMO. In order to substantially improve the current model, we need a better understanding of the FBP dynamics.

On 6/11/2020 at 2:36 AM, Floppy_Sock said:

The only two terms which have dynamics are the fatigue model and the cardiovascular response - it’s probably more than reasonable to fit them with some first order transients to keep the model simple.

The energy store that leads to the observed FBP is actually adenosine triphosphate (ATP) buffer present in the neurons. It's the same energy source that is being used during 100 m sprint runs. The key to modeling a dynamic FBP during air combat is to understand how fast the FBP is being restored under physical strain. Since neurons cannot generate ATP via anaerobic lactic acid fermentation, the brain must be oxygenated in order to begin to restore ATP levels, and therefore FBP. I have no idea how fast or slow this process is. In addition, one should also look at the dynamics of brain glucose levels under physical strain.

The expected FBP at the beginning of a fight should indeed be around 9 seconds, but I'd expect that to quickly diminish after the first few seconds of heavy maneuvering.

[Floppy_Sock]

5 hours ago, JG27_PapaFly said:

That would make a lot of sense IMO. In order to substantially improve the current model, we need a better understanding of the FBP dynamics.

The energy store that leads to the observed FBP is actually adenosine triphosphate (ATP) buffer present in the neurons. It's the same energy source that is being used during 100 m sprint runs. The key to modeling a dynamic FBP during air combat is to understand how fast the FBP is being restored under physical strain. Since neurons cannot generate ATP via anaerobic lactic acid fermentation, the brain must be oxygenated in order to begin to restore ATP levels, and therefore FBP. I have no idea how fast or slow this process is. In addition, one should also look at the dynamics of brain glucose levels under physical strain.

The expected FBP at the beginning of a fight should indeed be around 9 seconds, but I'd expect that to quickly diminish after the first few seconds of heavy maneuvering.

 

Yes you're correct about that. I know very little about biology (I study compressible flow and control theory).

 

That being said, see the following excerpt from the following paper,  

 

Tripp, L. D., Warm, J. S., Matthews, G., Chiu, P. Y., & Bracken, R. B. (2009). On Tracking the Course of Cerebral Oxygen Saturation and Pilot Performance During Gravity-Induced Loss of Consciousness. Human Factors, 51(6), 775–784. https://doi.org/10.1177/0018720809359631

Quote

Clearly, the prolonged performance recovery
time in GLOC cannot be attributed to delays
in the return of rSO2. As described by Dirnagl,
Iadecola, and Moskowitz (1999), ischemia, and
the subsequent hypoxia that follows, causes
a critical shortage in brain energy as neurons
use glucose and oxygen faster than they are
being supplied. At the cellular level, this energy
depletion is accompanied by a failure of the Na+
and K+ pumps critical for depolarizing neuronal
membranes, which in turn causes conductivity
to cease, resulting in a substantial loss of neural
firing. The accumulation of metabolite byproducts
during ischemic hypoxia delays the
recovery of normal neurological function following
rSO2 return. Therefore, it would appear
that the need to clear away the metabolic residue
of GLOC-induced hypoxia may be partly
responsible for the prolonged performance
recovery period even though rSO2 levels are at
or above baseline values.

For a first stab at this, I think? (please correct me if I'm way off here) it's reasonable to assume the glucose/oxygen consumption rate of neurons is constant. One would need to derive a transfer function from cerebral blood pressure to rate of removal of metabolic residue to properly characterize the transient behavior of the FBP. 

 

 

[BraveSirRobin]

On 6/10/2020 at 6:37 AM, HRc_Tumu said:

because really i cant understand except if i accept first this simple rule.... axis pilots have better tolerance... and i allways thinked the tolerance for all pilots was the same... .

 

On theory are the same or not ? 

 

 

My theory is that whoever I’m fighting will have the best g tolerance that has ever been accomplished in all of human history.  While I will be blacking out at 2g.

Edited June 13, 2020 by BraveSirRobin

[taffy2jeffmorgan]

Hi All, I am all for realism and the recent introduction of the G force effect with no option for turning it off, does give us some idea of what the pilots actually experienced during combat, but this effect has decreased my combat victories dramatically, I am finding it frustrating.  I work hard to get into position for a deflection shot [ which took me some time master ] and just about to pull the trigger and the screen starts to go black !  and my target has buggered off and who seems to be pulling a tighter curve than me with impunity. any one else experiencing this

 

Cheers

[JG27*PapaFly]

On 6/13/2020 at 8:14 PM, Floppy_Sock said:

For a first stab at this, I think? (please correct me if I'm way off here) it's reasonable to assume the glucose/oxygen consumption rate of neurons is constant.

I think that would be a safe assumption. However, after a pilot has exhausted his FBP and maintains a maximum g load on the verge of a blackout, 100 percent of the available oxygen will serve to cover the costs of maintaining consciousness. No oxygen will be available to replenish the FBP. The main question remains: how long and to what extent does the pilot need to relax Gs in order to fully restore his FBP?

[Kalo]

I am also a long time sim player and have been reading books on air combat for decades. My favorite stories have always been in first person account type books as I loved being able to relate to what pilots had to go through in combat. 

I agree 100% with Gate and all the other posters that said something is wrong with the current G-Loc model

 

1st question I would pose to the developers:

If you have any data that you consider accurate then it must have an upper range vs. a lower range of avg time to G-loc loss of consciousness in various tested or observed pilots\test subjects. Why would you not take something close to the top tier results (max time to G-loc) and let us pilots experience what it's like to be the best of the best pilots. We want to be like the great aces and our heroes we have idolized. The best of the best did not black out in 2-4 seconds. This is not historically accurate for any of the pilots memoirs i've read. I could go into the many mentions I recall of black outs in books but they were rare.

 

2nd question:

Why would you model some allied types getting G-suits?? They already have an assortment of planes that are fast and tend to have the advantage in horizontal maneuver over the German aircraft as in reality. So why would you give them any extra advantage in avoiding blackout when they generally out turn us anyway? Also from everything I have read those early G-suits were far from standard issue, Of differing builds water vs. air, and often didn't work.

 

Where is the tunnel vision before the loss of consciousness? As I understand during this time frame you are still conscious and under control of the aircraft. You are losing your vision but you don't just immediately go limp unconscious and lawn dart.

 

Where are gray outs? Perhaps if you are flying too aggressive graying out too much you will reduce your time to G-Loc like how it currently lasts longer and longer the more times you black out on a sortee

 

What actually happens to the aircraft in the current game model when things appear to be fully blacked out? Is my virtual pilot still holding the last command input on the flight stick for some further length of time between loss of vision and unconsciousness? 

I can say that if my virtual pilot was holding last command input for a second or 2 after my screen was black I probably would avoid the worst of the incidents of G-loc into the ground. Or at least allot I can seem to remember where I'm pulling out of some evasive emergency escape dive and i see the ground coming, i also completely see that I will make the pullout in time but G-loc onset starts occurring and it becomes a race of a split second between pullout or blackout........ I absolutely hate this because i firmly believe that an experienced pilot in a high pucker factor situation is gonna make that pullout 95% of the time whether it seems super human or not and gray out or black out on the way up after. People do amazing things to avoid dying..........

(which brings to mind the other situation I am beginning to hate seeing repeat... the P-51 on my tail pulling deflection with his G-suit advantage, combat flaps out and me in my 109 or FW starting to black out fully knowing easing up just a hair on my sustained turn and I will be 100% sure PK'd by the current model .50cals once he gets that hair more lead angle. I mean if his plane is better in the horizontal and is modeled to be able to out turn me then cool let that happen and let me go down for choosing the wrong maneuver in this often rock paper scissors game but blacking out like that far too often in a split second when my pilot would be pulling for all he's worth in life to avoid being swiss cheesed suxxxx)

 

If Jason or any of the Devs read this. Know this, I love what you have created and continue to update and make better. But..... the 2 most important things that need to be fixed IMHO are the spotting issue and behind that for me is G induced LOC. 

I want to fly on the edge of the envelope like the aces did, the best of the best and I really feel your G-Loc model is holding me back from my full ability.

Now these planes are not UFOs and yes there has to be G-loc. But it should be modeled generously and match what the best pilots were capable of. Not Herr Fatty Feldwebel adjutant from Stab who barely ever got a combat sortee

 

Kalo

 

 

[Bremspropeller]

The most important issue is never talked about:

 

- Is the pilot trained/ fit for increased g-tolerance and is he anticipating the gs, or is he just sitting in his seat fat, dumb and happy, when he bangs on those gs?

- Does the game simulate g-straining at all?

 

 

 

[Mainstay]

I noticed that especially in the Tempest G-Loc kicks in faster then other aircraft... 

 

Dont know why but is this behavior normal in this plane?

[nesher666]

AFAIK it is due to the fact of the rapid G onset rate, which is very much possible in the Tempest due to the overall high elevator responsiveness/authority, plus you have no G suit.

[=362nd_FS=RoflSeal]

Quote

 

2nd question:

Why would you model some allied types getting G-suits?? They already have an assortment of planes that are fast and tend to have the advantage in horizontal maneuver over the German aircraft as in reality. So why would you give them any extra advantage in avoiding blackout when they generally out turn us anyway? Also from everything I have read those early G-suits were far from standard issue, Of differing builds water vs. air, and often didn't work.

 

 

 

G-suits were mandatory in the 8th AF fighter pilots and optional for 9th AF pilots for P-47s and P-51s from August 1944 onwards.

Edited July 11, 2020 by =362nd_FS=RoflSeal

[Kalo]

If you want to really put forth the notion that every pilot in the 8th AF was flying combat missions using G-suits from 8/44 onward ok. I think that is most likely bunk but ok. So how do you mitigate that on online servers where the scenarios are not super late war, the Axis doesn't get it's top dogs the 109K4 and FW190D but we are facing Mustangs, Tbolts and Lightnings just minus the 150 octane. They are still fully modeled w the Gsuits active. NOT HISTORIC

 

Then there's this which equally effects everyone. Why is G-Loc straight to blackout while skipping steps 1 and 2... gray out and then tunnel vision?? This can be easily modeled. Not to diminish anyone's work in programming something into a simulation but..... Graying the screen for the appropriate amount of time before going into a rapidly increasing tunneling of the vision into blackness is not that difficult.

 

Operation[edit]

If blood is allowed to pool in the lower areas of the body, the brain will be deprived of blood, leading to temporary hypoxia. Hypoxia first causes a greyout (a dimming of the vision), also called brownout, followed by tunnel vision and ultimately complete loss of vision 'blackout' followed by g-induced Loss Of Consciousness or 'g-LOC'. The danger of g-LOC to aircraft pilots is magnified because on relaxation of g there is a period of disorientation before full sensation is re-gained. A g-suit does not so much increase the g-threshold, but makes it possible to sustain high g longer without excessive physical fatigue. The resting g-tolerance of a typical person is anywhere from 3–5 g depending on the person. A g-suit will typically add 1 g of tolerance to that limit. Pilots still need to practice the 'g-straining maneuver' that consists of tensing the abdominal muscles in order to tighten blood vessels so as to reduce blood pooling in the lower body. High g is not comfortable, even with a g-suit. In older fighter aircraft, 6 g was considered a high level, but with modern fighters 9 g or more can be sustained structurally^{[citation needed]} making the pilot the critical factor in maintaining high maneuverability in close aerial combat.^{[citation needed]}

[BraveSirRobin]

5 minutes ago, Kalo said:

 

Then there's this which equally effects everyone. Why is G-Loc straight to blackout while skipping steps 1 and 2... gray out and then tunnel vision?? This can be easily modeled.

 

It is modeled.  The problem is that lots of people just yank back on the stick and skip steps 1 and 2 all on their own.  If you fly with a little finesse instead of ham fistiing around the sky you will see that steps 1 and 2 are nicely modeled.

[=362nd_FS=RoflSeal]

19 hours ago, Kalo said:

If you want to really put forth the notion that every pilot in the 8th AF was flying combat missions using G-suits from 8/44 onward ok. I think that is most likely bunk but ok.

From DTIC document a955241, 11th Aug 1944

From NASA's Dressing for Altitude

 

In addition the US Navy had their own anti-G suite programme, adopted the G-suite as standard issue earlier then the USAAF, and issued 4000 units for SB2C Helldiver, F6F Hellcat, FM-2 Wildcat and F4U Corsair pilots over the war
 

 

Edited July 12, 2020 by =362nd_FS=RoflSeal

[-Pepegga-Armor]

I just thought I'd share this video about G-suits in USN service. 

Literally has 0 contribution to the topic but thought it'd be a nice watch

 

[JG7_X-Man]

On 7/11/2020 at 10:19 AM, =362nd_FS=RoflSeal said:

G-suits were mandatory in the 8th AF fighter pilots and optional for 9th AF pilots for P-47s and P-51s from August 1944 onwards.

 

Now can they have been mandatory in August '44 if they were not "standard issue" until November of '44?  

 

The true story - and ever vet here will agree to, it's like wearing your flak jacket ALL THE TIME! Yeah it may help stop a bullet (if you are hit in the torso) but the uncomfortability of it made it more of a hassle and was left behind on my rack! 

Edited July 12, 2020 by JG7_X-Man

[=362nd_FS=RoflSeal]

16 minutes ago, JG7_X-Man said:

 

Now can they have been mandatory in August '44 if they were not "standard issue" until November of '44?  

 

The true story - and ever vet here will agree to, it's like wearing your flak jacket ALL THE TIME! Yeah it may help stop a bullet (if you are hit in the torso) but the uncomfortability of it made it more of a hassle and was left behind on my rack! 

Standard issue implies being issued to more then just the 8th and 9th Air Force.

[LukeFF]

5 hours ago, JG7_X-Man said:

The true story - and ever vet here will agree to, it's like wearing your flak jacket ALL THE TIME! Yeah it may help stop a bullet (if you are hit in the torso) but the uncomfortability of it made it more of a hassle and was left behind on my rack! 

 

I'm a vet, and I can tell you there was severe punishment for those who didn't want to wear their body armor in Iraq. It really wasn't a choice. 

[=FEW=N3cRoo]

What also is a complete unknown to me is fatigue recovery in IL-2, it seems to be atleast 10 minutes of either no pulling at all or you may simply not recover... me and ppl i fly with pretty much get a new pilot after you overG once.

I also wanna point out there is hysteresis in the sound excecution.
https://youtu.be/4OqMCn7i-W4

 

The system is needed for any flight sim and needs some time spend on it, with such a simple thing as hysteris not being thought of I really have to ask for more time dedicated to it.
 

[Bremspropeller]

Does

the

pilot

strain

?

 

Is

he

just

a

fat

couch

slob

?

[RedKestrel]

1 hour ago, Bremspropeller said:

Does

the

pilot

strain

?

 

Is

he

just

a

fat

couch

slob

?

I read this in Werner Herzog's voice.

[Floppy_Sock]

3 hours ago, Bremspropeller said:

Does

the

pilot

strain

?

 

Is

he

just

a

fat

couch

slob

?

 

 

 

The sound is there? xD

[Bremspropeller]

Yeah, but it seems to not be quite effective.

Must be asthma.

[Floppy_Sock]

30 minutes ago, Bremspropeller said:

Yeah, but it seems to not be quite effective.

Must be asthma.

Well yeah - you hear that breathing at 13 seconds in? 500 breaths per second doesn't seem very healthy 

[Nazgul*]

On 6/10/2020 at 8:36 PM, Floppy_Sock said:

Oxygen stored in the brain tissue at next simulation step 

 

Unlike muscle, which can store small quantities of oxygen in association with myoglobin, neurons do not store oxygen in any meaningful way. Brain cells are therefore exclusively dependent on blood perfusion to function since their energy demands can only be obtained by aerobic metabolism and/or metabolism of ketones.

 

On 6/13/2020 at 8:50 AM, JG27_PapaFly said:

Since neurons cannot generate ATP via anaerobic lactic acid fermentation.

 

Incorrect. The brain can produce ATP via anaerobic respiration (primarily via glial cells but also neurons) but the levels produced are nowhere near the ones required to maintain homeostasis which, as you stated, makes the brain an oxygen-dependent tissue. ATP is however generated in small quantities during ischemia through anaerobic glycolysis. This system also works, acutely, to stimulate ventilation by the central chemoreceptors in the brain due to elevation in the levels of CO2 (indirectly increased by increased levels of H+ associated with the local lactic acidosis).

[Floppy_Sock]

25 minutes ago, Nazgul* said:

 

Unlike muscle, which can store small quantities of oxygen in association with myoglobin, neurons do not store oxygen in any meaningful way. Brain cells are therefore exclusively dependent on blood perfusion to function since their energy demands can only be obtained by aerobic metabolism and/or metabolism of ketones.

 

 

Incorrect. The brain can produce ATP via anaerobic respiration (primarily via glial cells but also neurons) but the levels produced are nowhere near the ones required to maintain homeostasis which, as you stated, makes the brain an oxygen-dependent tissue. ATP is however generated in small quantities during ischemia through anaerobic glycolysis. This system also works, acutely, to stimulate ventilation by the central chemoreceptors in the brain due to elevation in the levels of CO2 (indirectly increased by increased levels of H+ associated with the local lactic acidosis).

You clearly understand way more of this than I do - maybe I can ask you a few questions when I come back to this.

 

So where does the metric "brain tissue oxygenation" fall into this discussion? If I understand it correctly, that includes all brain tissue and surrounding fluid. This is the wordage that is used in the papers on this topic that I've read. 

 

On another note, given what you said in your response to Papafly, is length scale for anaerobic respiration an explanation for the 9 second buffer period?