G-LOC Question

[HornyU2]

In response to the question about tall and skinny......................


I'd say they were about 6'3" to 6'4" and maybe 185 lbs or so. Don't get me wrong, I've flown with plenty of tall and skinny dudes who had no G issues at all, they obviously figured it out. That's just it though, I'm sure they have a damn good G strain- compared to the one needed for a guy built like George Costanza. Sadly, Costanza has the ideal body type for pullin G's. High blood pressure and all, probably would have a ridiculously high resting G tolerance. I would like to have seen a Top Gun movie in which George Costanza and Chris Farley
(or Danny Devito) whipped the piss out of Maverick (and a G-Loc'd Goose - gives a whole new opportunity for him to say "Talk to me Goose"), while raging around in 9-G circles.

 

[Catmando]

Interesting discussion. But G-Loc is a relatively new term and focus for the US.

Back in the day it wasn't much of an issue. It was "tunnel vision, grey out, and maybe rarely, black out." But it didn't seem to be much of an issue back then and was rarely discussed... except for an occasional laugh in the debrief.

Our squadron had short, fat, tall, thin, athletes and couch potatoes. But no one seemed to have any problems with 6.5 Gs. (Which was the F-4 training limit; 7.5 G combat limit - periodically exceeded .)

Of course if you had been on leave, or had been bouncing or doing only intercepts for a few weeks, your G tolerance went down significantly. And it took a while to regain your G tolerances, despite body shape or physical fitness.

But if you flew ACM every day, your tolerance would increase by a couple of Gs. I used to grey-out occasionally, but never blacked-out. Just eased the G, tightened up some more, and then reapplied the G. No big deal. And no angles really lost. I did have RIOs black out occasionally, but usually when G was applied when they weren't expecting it, and hadn't yet tightened up. (I'm told they didn't like that much, either.) :icon_smil

But G loss of consciousness indeed was a big deal in WW-II for the German dive-bombers.

The 'Stuka' Junkers Ju 87 on a bomb run dived at a 60-90 degree angle at over 300kts with a bomb release point of only 1,500'!

Because of the large G forces to recover without hitting the deck, the German pilots too often blacked-out. Therefore, the Stuka had an automatic dive recovery system in case the pilot was incapacitated.

Many years ago I worked with a former German Flight Surgeon (some said he was Hitler's, but that was BS I'm sure). At the end of WW-II he was working on an articulating seat for the Stukas that would automatically recline somewhat when high Gs were encountered. But the war ended before he had a prototype.

With the advent of the next (now current) generation of fighters, the Navy was concerned with the anticipated greater G forces the newer aircraft could sustain, but not the crews. So they hired this old German Flight Surgeon to R&D an articulating and variable reclining ejection seat for the next generation.

I rode the Naval Air Development Center's centrifuge (too) many times for this old and heavily German accented codger in testing and designing his reclining ejection seat. I was able to get up to 12 sustained Gs with it, but it hurt really badly. And while conscious, I was mostly incapacited... although I could still Fox-2!!!

I decided (with my boss's strong suggestion) to quit the project before all my internal organs were totally misplaced and rearranged. But it was an interesting project along with the old Flight Surgeon with an interesting history.

 

[mmx1]

In response to the question about tall and skinny......................


I'd say they were about 6'3" to 6'4" and maybe 185 lbs or so. Don't get me wrong, I've flown with plenty of tall and skinny dudes who had no G issues at all, they obviously figured it out. That's just it though, I'm sure they have a damn good G strain- compared to the one needed for a guy built like George Costanza. Sadly, Costanza has the ideal body type for pullin G's. High blood pressure and all, probably would have a ridiculously high resting G tolerance. I would like to have seen a Top Gun movie in which George Costanza and Chris Farley
(or Danny Devito) whipped the piss out of Maverick (and a G-Loc'd Goose - gives a whole new opportunity for him to say "Talk to me Goose"), while raging around in 9-G circles.

Oddly enough, the last American ace (even accounting for two years' worth of retirement weight) looks like he's got a Costanza build:

I may or may not have posted this, but the accompanying article by Mark Bowden was pretty good.
http://www.theatlantic.com/doc/200903/air-force

 

[bunk22]

Oddly enough, the last American ace (even accounting for two years' worth of retirement weight) looks like he's got a Costanza build:

I may or may not have posted this, but the accompanying article by Mark Bowden was pretty good.
http://www.theatlantic.com/doc/200903/air-force

He's not an ace in the traditional sense but has the most fighter kills since Vietnam (3). I believe 2 other US pilots have 3 kills but trainers are a part of their scores. I believe one Sea Harrier pilot has 4 (2 A-4's and 2 helo's) but the helo's are never listed for him on the official list. Back to topic.

 

[rondebmar]

<<<Interesting discussion. But G-Loc is a relatively new term and focus for the US.

Back in the day it wasn't much of an issue. It was "tunnel vision, grey out, and maybe rarely, black out." But it didn't seem to be much of an issue back then and was rarely discussed... except for an occasional laugh in the debrief.

Our squadron had short, fat, tall, thin, athletes and couch potatoes. But no one seemed to have any problems with 6.5 Gs. (Which was the F-4 training limit; 7.5 G combat limit - periodically exceeded .)>>>

Cat is spot on!! As an "Attack" (vice "Fighter") pilot back "in the day", most of our training involved weapons delivery, both conventional and "special", involving routine 4 G work...

Interesting point...couple years back, a visiting squadron at Boca Chica damn near lost a guy during a high speed ejection. I had a discussion with an NAS based rescue swimmer shortly thereafter...info was the Hornet (?) driver G-Loc'ed during high altitude ACM exercise...recovered at about 3000' AGL, 90 degrees nose down...and left the jet! One can only imagine his true airspeed.

He was very badly injured...faced a long road to recovery...

The mention of organ displacement tickled me...every time I have a routine chest X-ray...the involved techs comment on the length of my lungs!! Because of that, they sometimes have to re-take the image...genetics?...or too much time under 4 G load?

 

[redmidgrl]

So, after less running and more lifting, I easily passed the F-18 profiles in the 'fuge. Going from leg pressing 180 lbs to 280 lbs made a world of difference.

 

[D_Rob]

So, after less running and more lifting, I easily passed the F-18 profiles in the 'fuge. Going from leg pressing 180 lbs to 280 lbs made a world of difference.

Wo0t!:icon_mi_1

 

[weq820]

I have some dumb questions.

1. Does the centrifuge make people feel dizzy? Or is it just pressure?
2. What is SD?
3. Before pulling the 7+ Gs, what kind of opportunities does one have to build a little bit of tolerance?

 

[BigBadBoJenkins]

I have some dumb questions.

1. Does the centrifuge make people feel dizzy? Or is it just pressure?
2. What is SD?
3. Before pulling the 7+ Gs, what kind of opportunities does one have to build a little bit of tolerance?

1. Some people feel dizzy. Some nauseous. Most just feel really tired when it's all over.
2. I dunno
3. In primary you get a few Gs, but by the time you get to the centrifuge your tolerance has worn off. The best thing you can do to prepare is just stay in shape.

 

[MIDNJAC]

Oddly enough, the last American ace (even accounting for two years' worth of retirement weight) looks like he's got a Costanza build:

I may or may not have posted this, but the accompanying article by Mark Bowden was pretty good.
http://www.theatlantic.com/doc/200903/air-force

Kinda cool thing was that he was a former first tour A-10 driver, and B team guy when they went into combat on the Gulf. Hammered down his first kill on a lucky HVAAP or something of the like. Banged out another kill (or maybe more?) in the Balkans years later. Role model

 

[feddoc]

I have some dumb questions.

1. Does the centrifuge make people feel dizzy? Or is it just pressure?
2. What is SD?
3. Before pulling the 7+ Gs, what kind of opportunities does one have to build a little bit of tolerance?

1. What makes you feel dizzy is the decrease in oxygenated blood in the brain. Try putting some water in a balloon, then swing it in a circle. THAT is what is happening to the blood in your body; is is being drawn away from the brain.
2. SD????
3.Pull Gs...it is the best way to build tolerance. redmidgrl has it down, sorta. Pulling Gs is an athletic event; short on duration and long on max effort. Keeping blood from draining to the lower extremities (and keeping more blood in the torso so the heart doesn't have to work as hard at keeping *oxygenated* blood going to the brain) is critical. >> Stronger leg muscles =greater ability to forcefully contract/constrict those muscles = greater ability to constrict blood from flowing to the lower body = greater ability for the lungs/heart to keep O2 in the brain. O2 in the brain is key to avoiding GLOC.

Stay in shape is ok advice, but the kind of shape you stay in is critical. Your training should focus on short term, maximal effort events. Powerlifting is a good example. Marathons are not.

 

[cfam]

SD = spatial d? Just spitballing....

 

[feddoc]

SD = spatial d? Just spitballing....

Duh...yup, I bet that is it.

 

[weq820]

As far as getting sick...has little, if anything, to do with Gs and much more to do with the (often) accompanying SD.

Yeah, spatial disorientation makes sense. Thanks for the answers, guys!

 

[sevenhelmet]

The centrifuge has one other important aspect that makes you dizzy, and that is the Coriolis force resulting from the vastly shorter moment arm of the centrifuge versus the high-g turn radius of an aircraft. Coriolis force is the same reason you get dizzy on a merry-go-round, your inner ear senses angular motion (turn rate) as well as the resultant force vector you feel as "g", and the weird relationship between the two screws up your vestibular system. In the jet, your turn radius at max-g is measured in thousands of feet, leading to a reduced turn rate for the same amount of g, so the Coriolis force is greatly reduced. You also have a full set of visual cues that line up with what your body is feeling, making it easier to stay oriented.

I remember even at "baseline" in the 'fuge (about 1.4g while idling between profiles) the Coriolis force was pronounced, which made turning my head very disorienting. I had zero issues with G-LOC, but after they pulled me out of that thing, I was unable to stand on my own for about 30 minutes. The combination of long high-g profiles and extreme Coriolis force is what makes the 'fuge a miserable experience.