Pilot G-limit compared to the Bf 109 and Fw 190

[Yo-Yo]

We should probably hold off on comparing the BF-109 with the P-51, till after the update. The BF-109 is getting a more refined flight model. Once we have that flight model, it will allow us to better assess our future Mustang tactics against the K4 and visa versa, sans the G Suit and all. :thumbup: MJ

 

I do not know what it means - "refined model" :) but I guess some minor tweaks was made in cooling system.. I really have no idea what changes went to last release and what changes will be. Except rudder limits vs speed, of course... :)

[Yo-Yo]

Yes, I know that, thats exactly what I mean. P51 is a worse turner(because of sustained turn), having ability to pull more Gs without G suit negates itself and gives very little if no advantage to the Mustang, and thats the point. In any other aspect the plane is inferior, so why make it less superior in the one thing that it actually does better?

 

If the pilot can't go over 5G for a sustained G, that means that the 109 having worse high speed turn can follow it as I have to loosen the turn not to black out and 109 is going to gain on me at that time. Its only useful in scissors, but I can't just make a wide over 5G turn. This means that we emphasise the 109's sustained turn advantage and take away from the P-51's instantaneous turn advantage.

 

Basically the one thing Mustang has better, that beeing high speed maneuvrablity is impaired by the lack of G resistance. Especially taking into consideration that 109 pilot is not getting tired with heavy stick forces in the game, so he can do it all day.

 

I agree with Sithspawn, if the code was already there, it could be very well an option. Its also historically correct for the P-51 pilots in 1944 especially late to have those G suits on.

 

Possibly you are right and G-suit will be returned for the Mustang.

[Hummingbird]

Does the inclined seats and heightened foot rests in the German aircraft actually provide a G resistance advantage ingame Yo-Yo?

 

If so, then I don't see why you would remove the G-suit from the P-51 as in essence you'd then be unbalancing things in a pilot-capability sense.

[mjmorrow]

I do not know what it means - "refined model" :) but I guess some minor tweaks was made in cooling system.. I really have no idea what changes went to last release and what changes will be. Except rudder limits vs speed, of course... :)

 

Ok, cool, Yo Yo. I am sure I will like the improvements to the rudder and what not. The DCS BF-109 is a really neat ride. :thumbup: MJ

[Tintin]

a interesting link

 

https://heritageflightgeardisplays.wordpress.com/2010/03/27/anti-g-suits-in-ww2-usaaf-service/

[Solty]

Possibly you are right and G-suit will be returned for the Mustang.

 

Thank you YoYo. That's awesome news. I really appreciate your decision. .:pilotfly:

Edited September 30, 2015 by Solty

[Kurfürst]

Does the inclined seats and heightened foot rests in the German aircraft actually provide a G resistance advantage ingame Yo-Yo?

 

Same question here.

[OnlyforDCS]

He has already answered that question on the previous page, although he has hinted that the differences are not nearly as large as the OP and some other posters believe them to be. (Mostly by not doing methodical testing)

[Crumpp]

He has already answered that question on the previous page, although he has hinted that the differences are not nearly as large as the OP and some other posters believe them to be. (Mostly by not doing methodical testing)

 

Can you point that out please? I do not see a thing commenting on the physiology model except to say that in MP the Mustang does not benefit from the USAAF G-suit.

 

As I understand Yo-Yo post, the pilot physiology model is universal.

[OnlyforDCS]

Yes I believe that is the correct interpretation

Edited September 30, 2015 by OnlyforDCS

[Crumpp]

Why angle the seat and what does it do for a fighter pilot?

 

The posted investigation offers a mathematical model to simulate acceleration effects found in combat on a pilot.

 

The baseline G-Tolerance correlates to a relaxed Rapid Onset Rate (6G/s) threshold to loss of light. Loss of light means the pilot experiences complete lack of vision but is still conscious and not in G-LOC.

 

The method uses the distance between the eyes and the heart.

 

The basic formula for G tolerance:

 

G = Arterial blood pressure * (Specific density of Blood/ distance from the eyes to the aortic valve.

 

For our universal pilot:

 

98.4mmHG = Arterial blood pressure

 

13.6 Kg/M^3 = Specific density of Blood (Do not be confused by the units...it is really dimensionless)

 

385mm = Distance from the eyes to the aortic valve

 

In a 90 degree upright seat:

 

G = 98.4mmHG*(13.6/385mm) = 3.47G

 

In a 14 degree seat:

 

The effect of seat angle is to directly reduce the distance from the eyes to the heart at the inverse cosine of the angle from horizontal or sine of the angle from vertical.

 

90 degrees - 14 = 76 degrees

Sin(76) = .970

 

385mm * .970 = 373

 

G = 98.4mmHG*(13.6/373mm) = 3.58G

 

In a 25 degree seat:

 

90 degrees - 25 = 65 degrees

Sin(65) = .90

 

385mm * .90 = 347mm

 

G = 98.4mmHG*(13.6/347mm) = 3.85G

 

Well that is only .38G threshold increase. That seems pretty insignificant, huh?

 

That is not the whole story of the effect of incline. In fact, the threshold increase is pretty minor. It does make a difference when onset rate is accounted for but even that is not the major effect.

 

There is a real good physiological reason why modern fighter pilots G-protection consists of 4 basic ingredients, a G-suit, Pressurized Breathing System, AGSM, and an inclined seat.

 

the pilot will be able to tolerate the ACM for longer durations in reclined seats, the total "kills" will be increased significantly over those of the pilot flying the conventional upright seat. This observation was made by Burton and Shaffstall (11) who found a 274% increase in hits when using a 65' seat as compared with the 13' seat, when the increased sustainability at G was allowed to influence the results.

 

http://www.dtic.mil/dtic/tr/fulltext/u2/a178431.pdf

 

In my next post I will go over the details of G-Endurance and how our inclined seats makes such a huge difference as well as the consequences of a pilot exceeding his G-endurance.

Edited October 1, 2015 by Crumpp

[Crumpp]

What is G-Endurance?

 

Air Combat Maneuvering is an environment of multiple G levels over an indefinite period of time. It can last from several seconds to a few minutes.

 

G-Endurance is the ability to function in the ACM environment. It is only been recently studied and quantified. The mechanism's that cause G-Endurance limitations are not well known. Some correlation exists in such parameters as lactic acid build up but seems to most strongly correlate with respiration effects.

 

A typical Simulated Air Combat Maneuvering profile is shown below. Now I am sure some readers will note that most World War II Combat does not reach 7G's for 15 seconds of exposure...

 

 

Don't worry, the investigation concludes the data is applicable to any ACM environment that exceeds 3G. Surprisingly, the lower G ACM environment take longer for the human body to recover. Using a G-suit does not improve your G-Endurance.

 

The longer our pilot is exposed to the ACM environment, the less he can tolerate acceleration to the point of fatigue. Fatigue is noted by increases loss of light at reduced acceleration levels. The more G's our pilot is exposed too without a definite rest period, the less he can handle.

 

How does the pilots seat angle effect this? Quite dramatically....

 

 

You can see the mean increase in G-Endurance is 1 minute and 40 seconds comparing 13 degrees with 30 degrees. The difference between the two highest G-Endurance levels is 2 minutes and 40 seconds.

 

That means the same pilot has to quit the fight much earlier simply because his seat is upright.

 

The mathematical model for G-Endurance and fatigue limits is included in the report I posted previously.

 

 

A good pilot physiology model is just as important to World War II ACM as a good flight model.

 

:thumbup:

Edited October 1, 2015 by Crumpp
report links did not work....gotta find another way to share the info

[Hummingbird]

What was the difference in seating angle in the three aircraft then? (obviously taking into account the height of the footrests)

[Crumpp]

(obviously taking into account the height of the footrests)

 

Height of the footrest does not do anything. One study concluded it raised relaxed G tolerance ~.3G.

 

All the other studies have concluded it does nothing. Back angle seems to have the most influence on relaxed G-tolerance although some studies have taken into account neck angle.

 

The seat angles were taken from internet drawings.

 

P-51 = 14 degrees or 76 degrees from horizontal

 

FW-190 = 25 degrees or 65 degrees from horizontal

 

Bf-109? = Not sure

 

Spitfire Mk IX = not sure

Edited October 2, 2015 by Crumpp

[OutOnTheOP]

What is G-Endurance?

 

The longer our pilot is exposed to the ACM environment, the less he can tolerate acceleration to the point of fatigue. Fatigue is noted by increases loss of light at reduced acceleration levels. The more G's our pilot is exposed too without a definite rest period, the less he can handle.

 

How does the pilots seat angle effect this? Quite dramatically....

 

:thumbup:

 

But WW2 aircraft have a very hard time maintaining even 3G for anything more than a 15-20 second span; they just haven't the thrust to maintain hard G. One would need instantaneous G resistance (well, rapid-onset, to be more precise) for hard, high-speed maneuvers, but you're just never going to see the kind of G profiles like the study you reference.

 

Anecdotally, having flown an SF260 trainer in 3-6 G mock dogfighting, I can say that, without G-suit, and what I recall as a fairly upright seating arrangement, I had no issues whatsoever with any G-related issues, aside from fighting the weight of the helmet. I am a reasonably fit man, but not trained for anti-G technique. I really can't see the 3-4 G sustainable turns achievable in a WW2 aircraft having the kind of fatigue effects to which you're alluding.

Edited October 3, 2015 by OutOnTheOP

[Crumpp]

But WW2 aircraft have a very hard time maintaining even 3G for anything more than a 15-20 second span;

 

I disagree, most of the late war birds can maintain 3G or more. Have you worked the math?

 

 

I really can't see the 3-4 G sustainable turns achievable in a WW2 aircraft having the kind of fatigue effects to which you're alluding.

 

It is not me that alludes to anything. It is Burton and other medical doctors doing research to improve their countries Air Forces.

 

Read the research. The body gets just as exhausted pulling 3.5G's as it does 7G's. In fact, it takes longer to recover from the low G profiles than the high G ones.

 

BTW, Oskar Bösch would very much disagree with you. He once told me less than 5 minutes of hard ACM exhausted most guys. The science supports his experience.

 

http://www.luftwaffe.cz/bosch.html

[Crumpp]

Anecdotally, having flown an SF260 trainer in 3-6 G mock dogfighting

 

BTW..

 

AirCombat USA looks like a lot of fun!

 

[OutOnTheOP]

I disagree, most of the late war birds can maintain 3G or more. Have you worked the math?

 

Yes, they can *barely* manage 3G sustained. So... in the realm of 3-4 G for anything more than a couple seconds. Don't see how this is in any way in disagreement with what I said.

 

It is not me that alludes to anything. It is Burton and other medical doctors doing research to improve their countries Air Forces.

 

But it is you that alludes that this is relevant; that WW2 aircraft will find themselves in situations where sustained G-tolerance is significant enough that the minor difference in seat angle is meaningful. Either way, the G-suit should provide as much or more benefit to instantaneous G resistance, and the sustained rates are quite low; below (even according to the charts posted in this thread) where a pilot has any serious trouble coping even with a bolt-upright seat and no G-suit.

 

BTW..

 

AirCombat USA looks like a lot of fun!

It is. Expensive, though.

Edited October 3, 2015 by OutOnTheOP

[Crumpp]

OutOnTheOP says:

Yes, they can *barely* manage 3G sustained.

 

In a 90 degree upright seat:

 

G = 98.4mmHG*(13.6/385mm) = 3.47G

 

Loss of Light threshold is only 3.47G's.

 

In other-words, sustaining those 3G's take a toll on the body and is accounted for in Dr Burton research.

 

OutOnTheOP says:

But it is you that alludes that this is relevant;

 

Nope..it is not me.

 

G-LOC of pilots, then called "fainting in the air," first occurred in World War I (WW I) and may have been, even then, the cause of some military aircraft accidents (106).

The potential hazards of G-LOC in the more modem, high performance aircraft were first discovered by Dr. W. K. Stewart, while conducting research on the subject in fighter

aircraft for the Royal Air Force at the beginning of World War II (WW II). However, despite photographic evidence of G-LOC episodes in aircraft, the UK Flying Personnel Research Committee dismissed the "problem" by declaring that: (a) such episodes were "entirely typical of many aircrew"; and (b) unsuccessful pilots (certainly including those who suffered G-LOC) had already been shot down

(105).

 

A type of AGSM useful in flight was first discovered as a method to increase G tolerance by Stainforth of England in 1933(194). He found that straining the abdominal muscles increased G tolerances 2 G, from 4 to 6 G. He also observed that the breath should not be held under this condition, since it would interfere with venous return. Early in WW II, the Germans trained Stuka dive bomber aircrew to strain their abdominal muscles as an anti-G method by encouraging them to learn and practice ski jumping. The AGSM was developed for use by pilots of fighter aircraft at the Mayo Clinic by Dr. Earl Wood and

his colleagues, conducting acceleration research during WW II (213,216). They determined the physiologic basis of the pulmonary aspects of a type of AGSM called the M-l (for maneuver 1), and developed a method to teach it to pilots (214). The M-l, very efficiently and rapidly develops an increased intrathoracic pressure using a partially closed glottis. This type of AGSM was commonly used by pilots during WW II.

 

http://ftp.rta.nato.int/public//PubFullText/AGARD/AG/AGARD-AG-322///AGARD-AG-322.pdf

 

A detailed pilot physiology model such as presented by Dr Burton, U.S. Air Force School of Aerospace Medicine (USAFSAM) is very relevant to World War II ACM.

[BSS_Vidar]

A modern set of jet jeans only gives a pilot 1 extra G. Not sure how efficient the WWII bladders were. But I don't think LW pilots had a big advantage in G lock out.

 

V

[RoflSeal]

WW2 G-3 suits used by USAAF had ~1G resistance.

[GrapeJam]

Possibly you are right and G-suit will be returned for the Mustang.

 

It's almost 4 months and we still haven't got the G suit, I wonder when are we gonna get it :-S

[petertheduke21]

i think all should have the same g tolerance and mustang have better sustained tolerance with g suit. and if you disagree you obviously dont know what you are talking about because some fighter pilots black out at 6 g and some wont even black out at sustained 10g

[Solty]

Well... I am just waiting in patience for a patch that will bring back the G suit.:helpsmilie:

[otto]

Well... I am just waiting in patience for a patch that will bring back the G suit.:helpsmilie:

 

It's was a weird decision to take the G suit out of the game.But since the 1.5 major update i like it that the LW pilots black out harder than before because i know how hard i'm pulling.And the game is more immersive for me.

In 1.2 version there must have been a bug because sometimes i could pull 9 g and over with the 109 and not black out at all.This didn't happened all the time.