Jump to content

Max G-Force sustained at g-LOC


Recommended Posts

I stumbled onto a passage regarding the G-suits from Roger Freeman's "The Mighty Eighth War Diary" while trying to dig up some other info.  What's particularly interesting is that it states that the P-51s had an accelerometer installed (presumably as part of the G-suit mods).  This is really interesting as many 8th AF combat after action reports include pilots mentioning specific G's pulled.  I had never seen any mention before of an accelerometer and had always assumed that these were just guesses, but apparently they actually had the instruments installed.

 

ZYixukn.jpg?1

 

Some examples of combat reports where specific G numbers are given:

http://www.spitfireperformance.com/mustang/combat-reports/357-england-13sept44.jpg

http://www.spitfireperformance.com/mustang/combat-reports/357-gailer-12oct44.jpg

http://www.spitfireperformance.com/mustang/combat-reports/357-yeager-12oct44.jpg

 

Major Gordon Graham of the 355th Fighter Group describing his Dec 25th battle: "I dove straight down.  When I pulled out at 5,000 feet, I was pulling seven Gs.  My G-suit connection blew apart."

  • Upvote 1
Link to post
Share on other sites
  • 4 weeks later...

"G tolerance is an individual thing, heavily dependent on the pilot's physical health and fitness, height, fatigue, smoking habits, drug intake, etc. Most fighter pilots, with training, can learn to sustain about 5 Gs for a considerable time without ill effects. In addition to training shorter fighter pilots (a personal favorite), there are certain techniques and equipment which can increase G tolerance. In the area of equipment, the G suit is the most common. This is usually a trouserlike garment that incorporates inflatable bladders in the abdominal area and along the legs. These bladders are usually inflated by high-pressure air from the aircraft by an automatic valve in proportion to the G level at any moment. The G suit squeezes the pilot's lower extremities, and this tends to restrict the pooling of blood in these areas, thereby leaving more blood available for the upper body and head. A properly fitted G suit can typically increase a pilot's tolerance by about 1 G."
Shaw, "Fighter Combat", page 377
http://falcon.blu3wolf.com/Docs/Fighter Combat-Tactics and Maneuvering.pdf

Edited by Rattlesnake
  • Upvote 1
Link to post
Share on other sites
  • 3 weeks later...

Panthera is correct, btw, that modern inflatable G suits provide about 1G of added tolerance.  I am not allowed to post the references I have available to me unless I want to risk federal prison, so you'll just have to take my word on it.  I don't have any data regarding the libelle ones.

 

WWII-era G suits providing more than 1 G is not realistic at all.

Edited by JG13_opcode
  • Like 1
  • Upvote 2
Link to post
Share on other sites
On 6/19/2020 at 7:09 PM, JG13_opcode said:

Panthera is correct, btw, that modern inflatable G suits provide about 1G of added tolerance.  I am not allowed to post the references I have available to me unless I want to risk federal prison, so you'll just have to take my word on it.  I don't have any data regarding the libelle ones.

 

WWII-era G suits providing more than 1 G is not realistic at all.

Press release by the Luke AFB says that the most modern anti-g suits (FCAGS) give up to 3G of protection , double that of the older generation (ATAGS)

https://www.luke.af.mil/News/Article-Display/Article/358586/new-g-suit-comes-to-luke/

 

Link to post
Share on other sites

The money quote:

 

Quote

The anti-G straining maneuver has always been a pilot's number one defense against GLOC, offering them three to four Gs of protection, while the legacy suit provided only about 1.5 Gs of protection.

 

Jives with the technical docs I've read.

 

I met a few A-10 pilots who were all short stocky and muscular. That body type is best for AGSM endurance and I was told their mission profile usually requires high Gs.

Edited by JG13_opcode
Link to post
Share on other sites
52 minutes ago, JG13_opcode said:

If you've ever met an A-10 pilot they're almost all short stocky and muscular, because that body type is best for AGSM endurance and their mission profile usually requires 7-8Gs

 

I wave the BS flag. My three pilot training classmates that got the Hawg were all 6' something. And their typical sortie involved 4g maneuvering. Show me a Vn diagram that says a underpowered turbofan equipped, subsonic, mud moving, straight wing jet can simply pull 7-8g (for more than one turn before it's out of airspeed and ideas).  

Edited by busdriver
  • Like 1
  • Upvote 3
Link to post
Share on other sites
16 hours ago, busdriver said:

 

I wave the BS flag. My three pilot training classmates that got the Hawg were all 6' something. And their typical sortie involved 4g maneuvering. Show me a Vn diagram that says a underpowered turbofan equipped, subsonic, mud moving, straight wing jet can simply pull 7-8g (for more than one turn before it's out of airspeed and ideas).  

 

Disclaimer:  I'm not US Military.  It's possible I misunderstood/misremembered the 7-8 G figure, but the guys I met last summer were all under 6 feet and totally jacked.  Maybe I just happened to meet a bunch of gym rats /shrug

Edited by JG13_opcode
Link to post
Share on other sites
44 minutes ago, JG13_opcode said:

 

Disclaimer:  I'm not US Military.  It's possible I misunderstood/misremembered the 7-8 G figure, but the guys I met last summer were all under 6 feet and totally jacked.  Maybe I just happened to meet a bunch of gym rats /shrug

 

Even back in the Jurassic Era weight lifting was emphasized for all of us to help mitigate against GLOC. So that stands to reason. :salute:

Link to post
Share on other sites
On 6/22/2020 at 8:16 PM, =362nd_FS=RoflSeal said:

Press release by the Luke AFB says that the most modern anti-g suits (FCAGS) give up to 3G of protection , double that of the older generation (ATAGS)

https://www.luke.af.mil/News/Article-Display/Article/358586/new-g-suit-comes-to-luke/

 

 

Probably a typo as it's 1 G according to all the testing documentation, and then 2.5 G's with the new suit, although I haven't seen any test documents for the new air inflatable suits, only for the liquid bladder derivatives of the Li belle which is what F-22 pilots are now wearing. 

Link to post
Share on other sites
  • 1 month later...
On 5/2/2020 at 10:46 PM, KW_1979 said:

I stumbled onto a passage regarding the G-suits from Roger Freeman's "The Mighty Eighth War Diary" while trying to dig up some other info.  What's particularly interesting is that it states that the P-51s had an accelerometer installed (presumably as part of the G-suit mods).  This is really interesting as many 8th AF combat after action reports include pilots mentioning specific G's pulled.  I had never seen any mention before of an accelerometer and had always assumed that these were just guesses, but apparently they actually had the instruments installed.

 

ZYixukn.jpg?1

 

Some examples of combat reports where specific G numbers are given:

http://www.spitfireperformance.com/mustang/combat-reports/357-england-13sept44.jpg

http://www.spitfireperformance.com/mustang/combat-reports/357-gailer-12oct44.jpg

http://www.spitfireperformance.com/mustang/combat-reports/357-yeager-12oct44.jpg

 

Major Gordon Graham of the 355th Fighter Group describing his Dec 25th battle: "I dove straight down.  When I pulled out at 5,000 feet, I was pulling seven Gs.  My G-suit connection blew apart."

 

Avialogs has the relevant TO: https://www.avialogs.com/aircraft-n/north-american-aviation/item/4781-t-o-01-60j-60-installation-of-accelerometer-p-51d-and-p-51h

Link to post
Share on other sites
  • 2 months later...

357-england-13sept44.thumb.jpg.9eeabeb2bbd3ff5d74f6539232e77ee5.jpg

 

 

I'm not going to enter in a discussion /argument til the infinite. I dare to those who want to demonstrate the opposite to upload any video like this giving a decent answer about this. 

 

Disclaimer: THIS IS NOT A COMPLAIN. I only want to discover if there are people else than me that have suffered this phenomenon and if it really "matches" with actual numbers, tables,....Also with this vid I want to use it as a feedback to developers and encourage them to give any official answer to this or fix if it were an error.

 

P.D: the joystick inputs were different: in P-51D at fully back G's reached 7G's (shown in the footage), then relaxed the stick to reach 5-4 G's stable mantained tight turn, but entering small inputs in stick to stay in such stable turn. With 109 was different. Full back stick from the first break til pilot blackout, as simple as that.

Link to post
Share on other sites
33 minutes ago, Tatata_Time said:

I'm not going to enter in a discussion /argument til the infinite. I dare to those who want to demonstrate the opposite to upload any video like this giving a decent answer about this. 

 

I have a feeling that you are testing the P-51 without an anti-g suit. In game, USAAF pilots wear anti-g suits only when piloting the P-51D-15 in September 1944 or later. On Rheinland Summer Quick Mission, the P-51 does not have anti-g suit.

 

With the anti-g suit, the pilot can withstand 6G for about 30 seconds.

 

If you want to test the anti-g suit effectiveness, I think you should repeat the test using the P-51 with and without the anti-g suit instead of comparing to the G-14. Also, enable the "instrument panel" realism simplification to see an additional number after the decimal in the HUD accelerometer for increased precision.

Edited by Mitthrawnuruodo
  • Like 2
  • Upvote 1
Link to post
Share on other sites
4 hours ago, Mitthrawnuruodo said:

If you want to test the anti-g suit effectiveness, I think you should repeat the test using the P-51 with and without the anti-g suit instead of comparing to the G-14. Also, enable the "instrument panel" realism simplification to see an additional number after the decimal in the HUD accelerometer for increased precision.

Thank you anyway, but you're only partialy right. Same result in autumm map, so non acceptable result. A mustang pilot goes blackout before G-14 pilot (before somebody starts talking about seat inclination....mustang had it too).  I did the test for both, mustang & G-14 not exclusively for mustang. But the weirdest point of all this is the lack of visual Greyout effects in the G-14 even doing a break turn at almost 700 Km/H isn't it? I've compared P-51 with G-14 because they're direct opponents in Boddenplate, so you need to know how better performs  your A/C  than the enemy's one. It's a bit useless comparing Mustang with G-suit and Mustang without it, because they never clash in a combat one versus the other. Now I could affirm Mustang pilot got same blackout in summer Rhineland map than in Autumm map, but surprise!!! winter map is the only that include the G-point-suit effect. The only difference I've noticed in tests has been mustang pilot still going G-LOC almost 30 seconds before G-14's (could it really be the seat position?????: It can't be an almost 30 seconds advantage: nut(t)s., Same advantage than a G-suit gives to its pilot in a 6G sustained turn before blacking out???: double nut(t)s. 

BTW could you tell me where is officially explained the summer, Autumm or winter G-Suit- Gate? I've never read about it. Lack of G-suit in  Summer got its logics but in Autumm..... Now I figured out why pilots that normally fly germans don't want to play the only mission that runs in winter map (also the bad spotting in winter map) in CB server.

 

Is physiology a bit overdone? - General Discussion - IL-2 Sturmovik Forum 

If We apply this table to mustang with no G-suit we can conclude that for a sustained turn of 4-5 G's you will experiment greyout just before reaching 10 seconds and beyond that you will go blackout, as in the footage: blacking out at 16 seconds, but ..........the G-14..........who knows.... Germans won the war didn't they???????? Also your right when you affirmed mustang pilot can withstand 30 seconds at mantained 6G's, so the table also rules for the mustang with G-suit.

 

 

Edited by Tatata_Time
Link to post
Share on other sites
2 hours ago, Tatata_Time said:

A mustang pilot goes blackout before G-14 pilot (before somebody starts talking about seat inclination....mustang had it too).

 

Your test isn't uniform. In the initial video, the P-51 shows significantly higher accelerations on the HUD. The P-51 (without anti-g suit) and G-14 pilots have almost the same tolerance when the acceleration profiles are equal.

 

2 hours ago, Tatata_Time said:

But the weirdest point of all this is the lack of visual Greyout effects in the G-14 even doing a break turn at almost 700 Km/H isn't it?

 

No, it's not weird at all. The elevator control stiffens at high speeds, so you can't turn very sharply with the default trim setting. Apply nose up stabilizer trim for effective high-speed turns. You'll quickly lose consciousness if you do that.

 

2 hours ago, Tatata_Time said:

The only difference I've noticed in tests has been mustang pilot still going G-LOC almost 30 seconds before G-14's (could it really be the seat position?????: It can't be an almost 30 seconds advantage: nut(t)s., Same advantage than a G-suit gives to its pilot in a 6G sustained turn before blacking out???: double nut(t)s.

 

Again, you are testing incorrectly. Fly identical acceleration profiles for a fair test.

 

2 hours ago, Tatata_Time said:

BTW could you tell me where is officially explained the summer, Autumm or winter G-Suit- Gate? I've never read about it.

 

It was written in the changelog for the 4.502 update.

Edited by Mitthrawnuruodo
  • Upvote 2
Link to post
Share on other sites

My tests were to show how different are the visual grey & black out for the same high G number. Mate, you finally talk about A/C performances and habilities: I know 109 Max G load was arround 10 G's: ok,  but I'm talking about the human being inside it suffering G loads and its visual representation ingame in a similar tight turn at same high G. You talk about accelerantion, both A/C were a flying at arround 700 km/h at the initial break turn  both at full throttle during all exercise. I don't know what you mind with acceleration but they both were at high speed and in a tight turn at high G's. A 109 G-14, of course, is a 109 otherwise it would be a mustang, and a mustang is a mustang otherwise it would be a 109. Let's talk straight: A/C of course are different, they indeed were different, but the pilots inside them from both sides reacted the same way to a change in direction & speed ( definition of acceleration, cause G is not a force, Newton's fault naming it that way) also to the Jerk, (rate of change of acceleration)

3 hours ago, Mitthrawnuruodo said:

It was written in the changelog for the 4.502 update.

 

29. USAAF pilots wear G-suits only when piloting P-47D-22, P-51D-15 and P-38J-25 in September 1944 or later; (copy & paste from the original post)

Please, correct me  if I'm wrong in what I understand here: seems P-47 D-28, a newer variant than D-22, never wear G-suit (I guess it is more like an omission, I'm only guessing but we should check it out, just to confirm anyway),  also "in September 1944" could be interpreted as the whole september (it includes summer map cause september is summer time). Here it comes the best: "or later"......Anyway I've shown it in second video Autumm is same as summer map (no G-suit allowed in both maps), so "or later" means the one and only  winter map YES or YES.

 

Anyway, I said in first post to not discuss it "ad infinitum". I dare you to do anything better and fair, come here and show your results and also discuss them or not. Thx for your time and your corrections. I hope they will be helpful for your near demonstration.

Edited by Tatata_Time
Link to post
Share on other sites
2 hours ago, Tatata_Time said:

flying at arround 700 km/h at the initial break turn

 

You just can't make a hard break turn with a 109 at this speed, due to hard controls at high speed. The only way is to take the time to trim up and pull down a bit of flaps to be able to turn "like" the Mustang. Which is why you probably get less G effects with the 109 at high speed (but bigger radius). 

 

Just to make sure: G is not only a matter of speed, it also depend on elevator input (and so, elevator authority, which varies with aircrafts). 

Edited by JG300_Faucon
  • Upvote 2
Link to post
Share on other sites
3 hours ago, Tatata_Time said:

I dare you to do anything better and fair, come here and show your results and also discuss them or not. Thx for your time and your corrections. I hope they will be helpful for your near demonstration.

 

I’m not going to waste my time demonstrating anything when your claims can be debunked with one sentence.

 

The acceleration felt by the pilot (expressed in units called 'g' or 'G') is the cause of the physiological effects. Speeds are irrelevant for physiology - only the acceleration matters.

 

Your tests won't show anything useful until you fly similar acceleration profiles with both aircraft.

Edited by Mitthrawnuruodo
  • Like 1
  • Upvote 1
Link to post
Share on other sites

Just from watching the first video, with grey out starting to occur at 5G in the Mustang, the G-suit was definitely NOT equipped there.  Rheinland fall doesn't appear to give it to you either.  The actual cutoff date in the mission editor is 9/2/44 and later gets the G-Suit - IF you're set US (I suspect that Rheinland fall defaults to 9/1/44).  If you're set to a different country then no G-suit no matter the date.  If you get it setup properly so that you have it, it makes a very noticeable difference - easily a 1G advantage.

Link to post
Share on other sites
On 11/12/2020 at 9:23 AM, -332FG-KW_1979 said:

Just from watching the first video, with grey out starting to occur at 5G in the Mustang, the G-suit was definitely NOT equipped there.  Rheinland fall doesn't appear to give it to you either.  The actual cutoff date in the mission editor is 9/2/44 and later gets the G-Suit - IF you're set US (I suspect that Rheinland fall defaults to 9/1/44).  If you're set to a different country then no G-suit no matter the date.  If you get it setup properly so that you have it, it makes a very noticeable difference - easily a 1G advantage.

 

Are you saying that depending on the date chose by the mission maker (9/2/44), US aircrafts are equiped or not with G suit? Interesting, never knew about that. 

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...