Van's Air Force
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G-Force, effects on human body
- Thread starter ryykblum
- Start date
panhandler1956
Well Known Member
Interesting! Thanks for sharing!
smokyray
Well Known Member
Rick,
Trust me, 9G's does hurt but is something you can tolerate and live with on a daily basis, 20 years worth for me. Believe it or not, fighter G-suits only provide 1-1.5 G's worth of protection, the rest as they say is training...
Thanks for sharing...
V/R
Smokey
N355DW
Well Known Member
Copied from same thread
I went ahead and copied my post from the same thread, it's probably more appropriate here...
I left off the last part, as it was the appropriate part of my post for the other thread!
The person I quoted had said that 6 G's were a lot and that studies had shown that is where folks started to G-loc. I replied:
That's true, but as a general rule you would have to hold the six G's continuously for a lot longer than you would ever do it in most aerobatic maneuvers or sequences. Only if you are in a dog fight would you be likely to do this. Most of the time in aerobatics you will not be pulling hard G's for more than about three or four seconds at a time, that's about how long it takes to go 90 degrees, like from horizontal to vertical. If you tense your leg and stomach muscles before doing it you can pull far more than 6 G's for several seconds without greying out. I have pulled as much as 11 G's when my adrenaline got pumping at a contest now and then. I don't like pulling that much, the wing is at too high an angle of attack at that hard a pull, creating more drag, and you will scrub off too much energy, losing vertical performance or speed for the next maneuver. In the S2-B the best performance seemed to be around 5-6 G, and the Extra 230 liked about 6-7 G. The reason being the judges will grade you better if the corners are sharp and the vertical lines are long. Not supposed to be a grading criteria I know, but this is true nevertheless.
G effects on your body also can change based on things like how acclimated you are to G forces, whether you are dehydrated, tired, etc. It can also depend on how the maneuvers are strung together. One of the easiest ways to get G-loc is to fly inverted (-1G) for longer than 8-10 seconds or so, and then pull 4 or more G's suddenly. The way this was explained to me is when all the blood is going to your head for a bit while you are inverted, your autonomic nervous center lowers your blood pressure thinking it's too high, and then when you suddenly pull positive G's, your brain can't raise the pressure soon enough to compensate. A square loop is a good place for this to happen. Ask me how I know (I quit pulling hard when I started to grey out).
I went ahead and copied my post from the same thread, it's probably more appropriate here...
I left off the last part, as it was the appropriate part of my post for the other thread!The person I quoted had said that 6 G's were a lot and that studies had shown that is where folks started to G-loc. I replied:
That's true, but as a general rule you would have to hold the six G's continuously for a lot longer than you would ever do it in most aerobatic maneuvers or sequences. Only if you are in a dog fight would you be likely to do this. Most of the time in aerobatics you will not be pulling hard G's for more than about three or four seconds at a time, that's about how long it takes to go 90 degrees, like from horizontal to vertical. If you tense your leg and stomach muscles before doing it you can pull far more than 6 G's for several seconds without greying out. I have pulled as much as 11 G's when my adrenaline got pumping at a contest now and then. I don't like pulling that much, the wing is at too high an angle of attack at that hard a pull, creating more drag, and you will scrub off too much energy, losing vertical performance or speed for the next maneuver. In the S2-B the best performance seemed to be around 5-6 G, and the Extra 230 liked about 6-7 G. The reason being the judges will grade you better if the corners are sharp and the vertical lines are long. Not supposed to be a grading criteria I know, but this is true nevertheless.
G effects on your body also can change based on things like how acclimated you are to G forces, whether you are dehydrated, tired, etc. It can also depend on how the maneuvers are strung together. One of the easiest ways to get G-loc is to fly inverted (-1G) for longer than 8-10 seconds or so, and then pull 4 or more G's suddenly. The way this was explained to me is when all the blood is going to your head for a bit while you are inverted, your autonomic nervous center lowers your blood pressure thinking it's too high, and then when you suddenly pull positive G's, your brain can't raise the pressure soon enough to compensate. A square loop is a good place for this to happen. Ask me how I know (I quit pulling hard when I started to grey out).
n5lp
fugio ergo sum
Individual variation
I hardly pull Gs anymore but used to quite a bit. I am older and not in great shape but could pull 6 Gs for about as long as that is possible in an RV with no problem. If I pulled around 3.5 to 4.5 Gs for a longer period I could start to get tunnel vision that was easily controlled with the stick, which is really pretty cool. Pull to narrow the vision and relax the stick a bit to see more.
I thought it was really interesting when I took an aviation minded high school athlete up. This is a quarterback in really good condition; sort of tall and lean. He had no G tolerance at all and would start to gray out in very normal mild maneuvers at around 2.5 to 3.5 Gs. Today he is an airline pilot.
I hardly pull Gs anymore but used to quite a bit. I am older and not in great shape but could pull 6 Gs for about as long as that is possible in an RV with no problem. If I pulled around 3.5 to 4.5 Gs for a longer period I could start to get tunnel vision that was easily controlled with the stick, which is really pretty cool. Pull to narrow the vision and relax the stick a bit to see more.
I thought it was really interesting when I took an aviation minded high school athlete up. This is a quarterback in really good condition; sort of tall and lean. He had no G tolerance at all and would start to gray out in very normal mild maneuvers at around 2.5 to 3.5 Gs. Today he is an airline pilot.
G's
Typical contest flight in the Pitts S1S or S2B was 6G. When I started flying the Sukhoi I very quickly started pulling as much as plus 11 and negative 8.5. Because of the differences in the seats, 6 G's in the Pitts always seemed harder for me than 10 in the Sukhoi. A 10 G 90 degree corner is over so fast in the Sukhoi you hardly notice it.
Damon as always has some very concise information, I would only add that I think being tired and hungry is a big factor. I really run out of energy when my blood sugar is low. For contests I always had a good supply of high energy snacks.
Typical contest flight in the Pitts S1S or S2B was 6G. When I started flying the Sukhoi I very quickly started pulling as much as plus 11 and negative 8.5. Because of the differences in the seats, 6 G's in the Pitts always seemed harder for me than 10 in the Sukhoi. A 10 G 90 degree corner is over so fast in the Sukhoi you hardly notice it.
Damon as always has some very concise information, I would only add that I think being tired and hungry is a big factor. I really run out of energy when my blood sugar is low. For contests I always had a good supply of high energy snacks.
smokyray
Well Known Member
Try a 1V1 with a Raptor....
V/R
Smokey
PS: You haven't lived until you have someone trying to kill you...
That PS broke me up for its raw hosesty
Thanks Smokey - I needed that.
Bob Axsom
Try a 1V1 with a Raptor....
V/R
Smokey
PS: You haven't lived until you have someone trying to kill you...
Thanks Smokey - I needed that.
Bob Axsom
rvmills
Well Known Member
Try a 1V1 with a Raptor....
V/R
Smokey
PS: You haven't lived until you have someone trying to kill you...
...and you don't feel the g either, eh!
Sometimes you hear the GIB's voice change a bit, as he grunts..."watch...the...g..." (though if the bandit was real, he'd surely ask for more!)
As Ax said...as always brudda...you have a good way with words!
Cheers,
Bob
Mike D
Well Known Member
This might be slightly off topic but..
The article was interesting, and it got me thinking about what sort of impact G forces our RV's are built to. If you took the "outdated military standard" of 18G's, and used a 200lb pilot, could the standard vans restraint system hold up? In other words, can the seat belt mounts take a 3600 lb load? What about a 10K lb load (50G's)?
I would guess the belts and cables could, but what about the aluminum it is all mounted to?
I am not an engineer, so I would find it amazing that such a light structure would hold such a heavy load. Imagine a large SUV hanging from your seat belt!
The article was interesting, and it got me thinking about what sort of impact G forces our RV's are built to. If you took the "outdated military standard" of 18G's, and used a 200lb pilot, could the standard vans restraint system hold up? In other words, can the seat belt mounts take a 3600 lb load? What about a 10K lb load (50G's)?
I would guess the belts and cables could, but what about the aluminum it is all mounted to?
I am not an engineer, so I would find it amazing that such a light structure would hold such a heavy load. Imagine a large SUV hanging from your seat belt!
Not all G's are the same (well, they ARE, but...)
Here's a weird one:
- 6-9 Gs in a centrifuge sucks. I mean, everyone single one of those Gs just plain hurts. Doable, but an all-around miserable and nauseating experience.
- 6-9 Gs in the aircraft is a workout, but strangely enough it's an entirely different endeavor. That's because by the time you've worked up to the G over a few weeks and become sufficiently familiar with the muscle memory and the physical tasks (proper breathing, G-straining maneuver, etc), it is far easier to take into stride. Pulling Gs becomes a secondary task, like balancing on a bike, allowing you to concentrate on the primary task (killing the bandit, flying formation, etc).
Fighter pilots and WSOs run into trouble when the G-strain tasks become so second nature that they over-prioritize other tasks at the expense of the G-strain's required effort: The quality of their G strain backs off and they don't get/keep enough oxygen-rich blood to the brain. WSOs sometimes G-LOC because they can't always anticipate the pilot's high-G pull: They're immediately behind the G in the strain and can't push the blood back up to their brain (remember that when carrying a passenger in the RV-4, 6, 7, or 8). Some of you hit on other key aspects like hydration, nutrition, fatigue.
Pulling Gs is like shooting a nice firearm: It makes for absolutely thrilling sport, but you cannot just pick it up and pull the trigger...you MUST know how to do it first. Searching through "centrifuge training" on YouTube will give you an idea of the sort of effort required to pull just 6 Gs. (Warning: Viewing YouTube videos on centrifuge training does not constitute valid computer-based training ).
There are a few of us here in the VAF that work this issue quite often: I'm the Air Combat Command Director of Safety, and Paul Gardetto and Bruce Edwards are physiologists/flight surgeons here at the ACC Surgeon General. Feel free to ask us about Gs, pilot physiology, and their applications to aviation safety if you have a question...that?s what we do.
Here's a weird one:
- 6-9 Gs in a centrifuge sucks. I mean, everyone single one of those Gs just plain hurts. Doable, but an all-around miserable and nauseating experience.
- 6-9 Gs in the aircraft is a workout, but strangely enough it's an entirely different endeavor. That's because by the time you've worked up to the G over a few weeks and become sufficiently familiar with the muscle memory and the physical tasks (proper breathing, G-straining maneuver, etc), it is far easier to take into stride. Pulling Gs becomes a secondary task, like balancing on a bike, allowing you to concentrate on the primary task (killing the bandit, flying formation, etc).
Fighter pilots and WSOs run into trouble when the G-strain tasks become so second nature that they over-prioritize other tasks at the expense of the G-strain's required effort: The quality of their G strain backs off and they don't get/keep enough oxygen-rich blood to the brain. WSOs sometimes G-LOC because they can't always anticipate the pilot's high-G pull: They're immediately behind the G in the strain and can't push the blood back up to their brain (remember that when carrying a passenger in the RV-4, 6, 7, or 8). Some of you hit on other key aspects like hydration, nutrition, fatigue.
Pulling Gs is like shooting a nice firearm: It makes for absolutely thrilling sport, but you cannot just pick it up and pull the trigger...you MUST know how to do it first. Searching through "centrifuge training" on YouTube will give you an idea of the sort of effort required to pull just 6 Gs. (Warning: Viewing YouTube videos on centrifuge training does not constitute valid computer-based training
).There are a few of us here in the VAF that work this issue quite often: I'm the Air Combat Command Director of Safety, and Paul Gardetto and Bruce Edwards are physiologists/flight surgeons here at the ACC Surgeon General. Feel free to ask us about Gs, pilot physiology, and their applications to aviation safety if you have a question...that?s what we do.
N355DW
Well Known Member
Here's a weird one:
- 6-9 Gs in a centrifuge sucks. I mean, everyone single one of those Gs just plain hurts. Doable, but an all-around miserable and nauseating experience.
- 6-9 Gs in the aircraft is a workout, but strangely enough it's an entirely different endeavor. That's because by the time you've worked up to the G over a few weeks and become sufficiently familiar with the muscle memory and the physical tasks (proper breathing, G-straining maneuver, etc), it is far easier to take into stride. Pulling Gs becomes a secondary task, like balancing on a bike, allowing you to concentrate on the primary task (killing the bandit, flying formation, etc).
Fighter pilots and WSOs run into trouble when the G-strain tasks become so second nature that they over-prioritize other tasks at the expense of the G-strain's required effort: The quality of their G strain backs off and they don't get/keep enough oxygen-rich blood to the brain. WSOs sometimes G-LOC because they can't always anticipate the pilot's high-G pull: They're immediately behind the G in the strain and can't push the blood back up to their brain (remember that when carrying a passenger in the RV-4, 6, 7, or 8). Some of you hit on other key aspects like hydration, nutrition, fatigue.
Pulling Gs is like shooting a nice firearm: It makes for absolutely thrilling sport, but you cannot just pick it up and pull the trigger...you MUST know how to do it first. Searching through "centrifuge training" on YouTube will give you an idea of the sort of effort required to pull just 6 Gs. (Warning: Viewing YouTube videos on centrifuge training does not constitute valid computer-based training
There are a few of us here in the VAF that work this issue quite often: I'm the Air Combat Command Director of Safety, and Paul Gardetto and Bruce Edwards are physiologists/flight surgeons here at the ACC Surgeon General. Feel free to ask us about Gs, pilot physiology, and their applications to aviation safety if you have a question...that?s what we do.
Do you guys ever do much (or any) negative G studies these days? I have been out of serious competition for a while and haven't really kept up with the news on things like that. I know for a while back in the 90's the military was working with the IAC because we do so much more hard negative G in the competition world than the military does, and were investigating it's effects on the body, and things like the "wobblies" (G induced vestibular dysfunction) that arose from doing a lot of negative G. It was a real problem for some, especially the airline guys because it could strike at any moment, and could endanger their livlihood. I was lucky in that it never affected me, but you just couldn't tell who was going to have a problem. An airline pilot friend of mine got a detached retina and had to quit competition. I do not miss negative G!
Hornetdriver
I'm New Here
Absolutely agree, Scroll. G tolerance is all about learning proper technique (learning to ride the bike) and then the body becoming conditioned to pulling G's. Generally, you develop the technique and it becomes second nature. If I was out of the cockpit for a few weeks, you could feel it when you got back into a high G environment.
The only thing I would add to Scroll's comment is that you not only get accustomed to pulling G's, but actually look forward to it (or at least I did). Fights on!
The only thing I would add to Scroll's comment is that you not only get accustomed to pulling G's, but actually look forward to it (or at least I did). Fights on!
Gs in older pilots
Okay, Scroll,
I'll take you up on that offer.
I punched my ticket on the centrifuge ride when I was 45 or so. Probably not the smartest thing to do but I wanted it and it was required for where I was headed.
I don't recall seeing any data on age vs G-tolerance and when the risk of X amount of Gs becomes prohibitive, individual tolerance not withstanding., i.e pull on the aorta, etc.
Any comments?
Dave A.
6A build
Okay, Scroll,
I'll take you up on that offer.
I punched my ticket on the centrifuge ride when I was 45 or so. Probably not the smartest thing to do but I wanted it and it was required for where I was headed.
I don't recall seeing any data on age vs G-tolerance and when the risk of X amount of Gs becomes prohibitive, individual tolerance not withstanding., i.e pull on the aorta, etc.
Any comments?
Dave A.
6A build
RPorter
Active Member
Try a 1V1 with a Raptor....
V/R
Smokey
PS: You haven't lived until you have someone trying to kill you...
made my day
N355DW
Well Known Member
I can't quote any studies, but I suspect it's going to vary with the individual. I do have some anecdotal knowledge!
I took my original aerobatic instruction from Duane Cole back in the 80's. He was 72 and still flew airshows. Not real high G stuff, but he flew acro into his 80's, I believe. Henry Haigh won the World Aerobatic Championship when he was 64. I flew in a Sukhoi 29 once with Clint McHenry, and he was in his seventies and wore me out! Chuck Alley (also known as Ron Howard's father-in-law) flew in competitions well into his 80's. Other young-at-hearts - Clyde Cable, Tommy Adams, I could probably list a dozen more. Many have dropped back a category and are flying Intermediate instead of Advanced, but you still will pull 5 or 6 G's a dozen times or more in a sequence in Intermediate, it's the negative G that really hurts, and the reason most drop back to Intermediate. I think negative G is way more dangerous (save getting G-LOC while flying) for us as our bodies are at least designed for positive G's, maybe not so many as in military flying or competition, but the human body is just not built for negative. It's far more uncomfortable, even painful, and takes a lot more easing into than positive G.
G research
Folks,
Beers on me for the way-delayed response. Bugsy, FM, and I have been scattered to the 4 corners, juggling chainsaws, etc...pick your metaphor.
OK, I owe answers.
Damon--Negative Gs:
Most recent research confirms that negative Gs still suck. They're just painful, and the pain level is the limiting pilot on the pilot (unless you reach the airframe negative-G limit first). There are no effective G-strain maneuvers to mitigate the effect.
However, there is one new finding that high-performance pilots should pay attention, particularly in the sport pilot aerobatics area: The push-pull effect on the resting G tolerance window.
Every pilot has a resting G tolerance. That means if you slowly increase the G (say, 1/10 of a G per second, or one full G increase over 10 seconds) and DO NOT employ a G strain maneuver, the body will compensate with higher blood pressure and increased delivery to the brain. At some point, the body can't quite meet the demand and the pilot must strain. That's the resting G tolerance. In my last centrifuge spin, my resting G tolerance was about 5 Gs. Thus, my resting G tolerance window is 5 - 0 Gs, or a 5 G window.
The problem: That window slides left if we push negative Gs. So if I push to -2 Gs, my resting G window's top end is now at +3 Gs (-2 +5 = +3 Gs). If the pilot plans to execute a push-pull type maneuver transitioning quickly between negative to positive Gs, he must be prepared to execute a G strain at a lower positive G than he's/she's normally accustomed to. Otherwise, he's in danger of GLoC at a lower G than normal.
Dave--Older Pilots and Gs:
No new research here, but the existing research is still sound. As we age...er, season, our normal G tolerance decreases. Many factors impact this for good and bad: fitness, hydration, cardio vascular health, and particularly our frequency of exposure to Gs. We can keep our resting G tolerance up through good living, but we really have to anticipate G onset because the 'seasoning' body's ability to react to Gs decreases with age. The top-end G tolerance also decreases, and there's only so much a good G strain can do to combat GLOC in any pilot but particularly
Did I answer your questions? Again, sorry for the late reply.
Folks,
Beers on me for the way-delayed response. Bugsy, FM, and I have been scattered to the 4 corners, juggling chainsaws, etc...pick your metaphor.
OK, I owe answers.
Damon--Negative Gs:
Most recent research confirms that negative Gs still suck. They're just painful, and the pain level is the limiting pilot on the pilot (unless you reach the airframe negative-G limit first). There are no effective G-strain maneuvers to mitigate the effect.
However, there is one new finding that high-performance pilots should pay attention, particularly in the sport pilot aerobatics area: The push-pull effect on the resting G tolerance window.
Every pilot has a resting G tolerance. That means if you slowly increase the G (say, 1/10 of a G per second, or one full G increase over 10 seconds) and DO NOT employ a G strain maneuver, the body will compensate with higher blood pressure and increased delivery to the brain. At some point, the body can't quite meet the demand and the pilot must strain. That's the resting G tolerance. In my last centrifuge spin, my resting G tolerance was about 5 Gs. Thus, my resting G tolerance window is 5 - 0 Gs, or a 5 G window.
The problem: That window slides left if we push negative Gs. So if I push to -2 Gs, my resting G window's top end is now at +3 Gs (-2 +5 = +3 Gs). If the pilot plans to execute a push-pull type maneuver transitioning quickly between negative to positive Gs, he must be prepared to execute a G strain at a lower positive G than he's/she's normally accustomed to. Otherwise, he's in danger of GLoC at a lower G than normal.
Dave--Older Pilots and Gs:
No new research here, but the existing research is still sound. As we age...er, season, our normal G tolerance decreases. Many factors impact this for good and bad: fitness, hydration, cardio vascular health, and particularly our frequency of exposure to Gs. We can keep our resting G tolerance up through good living, but we really have to anticipate G onset because the 'seasoning' body's ability to react to Gs decreases with age. The top-end G tolerance also decreases, and there's only so much a good G strain can do to combat GLOC in any pilot but particularly
Did I answer your questions? Again, sorry for the late reply.
David-aviator
Well Known Member
One aspect missing in this discussion are the consequences of G loads on the lower rectum.
Some years ago I had to go see a hemorrhoid doctor due to occasional out of control bleeding - not a good deal for one flying for a living and away from home a lot.
The fix was surgery, body flat out on a gurney with your butt elevated about a foot, and the doc doing his thing with his sharp instruments and clamps and several nurses attending and me thinking there must be a better way. That part was easy being partially sedated but the recovery was very unpleasant and lasted about 10 days. My wife still laughs about finding me in the middle of the night in a bath tub full of water sitting on the hospital issued "sitz stool".
During the initial interview, the doctor commented with a chuckle, you are a pilot - most of my patients are.
Perhaps an equal number of negative and positive G load experiences would alleviate this unpleasant consequence for some - I don't know.
Some years ago I had to go see a hemorrhoid doctor due to occasional out of control bleeding - not a good deal for one flying for a living and away from home a lot.
The fix was surgery, body flat out on a gurney with your butt elevated about a foot, and the doc doing his thing with his sharp instruments and clamps and several nurses attending and me thinking there must be a better way. That part was easy being partially sedated but the recovery was very unpleasant and lasted about 10 days. My wife still laughs about finding me in the middle of the night in a bath tub full of water sitting on the hospital issued "sitz stool".
During the initial interview, the doctor commented with a chuckle, you are a pilot - most of my patients are.
Perhaps an equal number of negative and positive G load experiences would alleviate this unpleasant consequence for some - I don't know.
Adam Oke
Well Known Member
This might be slightly off topic but..
The article was interesting, and it got me thinking about what sort of impact G forces our RV's are built to. If you took the "outdated military standard" of 18G's, and used a 200lb pilot, could the standard vans restraint system hold up? In other words, can the seat belt mounts take a 3600 lb load? What about a 10K lb load (50G's)?
I would guess the belts and cables could, but what about the aluminum it is all mounted to?
I am not an engineer, so I would find it amazing that such a light structure would hold such a heavy load. Imagine a large SUV hanging from your seat belt!
Even if it does hold, the body can only sustain so much G in sudden stoppage. Think of all of your internals in motion, with a 10-50G impact. The the frame and belts hold you, your internals will come to an abrupt stop and impact ribs etc. Most Ag planes have a cage to withstand around 40G. You're body should be fairly protected. So I always think it is a case of if you are lucky enough to survive the impact. Hopefully there is enough crumple factor to help absorb some energy.
N355DW
Well Known Member
Hey, very cool, thanks for checking on it!
I noticed I had more trouble on the push pull type of maneuvers if I held negative G, even as little as -1 negative G, for a longer period of time, say 6 or 7 seconds, and then pulled 4 or more positive G quickly thereafter. A maneuver like a square loop.
On something like an outside snap an a downline, with a pull out, you might hit 4 or 5 negative G in the snap, followed within about 2 to 3 seconds seconds a +6 or +7 G pull. That seemed to be easier to deal with than my first scenario. The snap hurts though, good to know research confirms they suck!
What I would really be interested in would be any further research into "the wobblies" (g induced vestibular dysfunction). There were several theories floating around back in the nineties about why negative G would cause this, and what the causes were, but I don't think there was ever anything definitive. Since we sport aerobatic types are the only ones dumb enough to do this negative stuff regularly, I guess it's not worth the time and money to investigate too thoroughly, and I understand that, but I was curious if there had been anything since what we knew in the nineties about it.
Thanks again,
Damon
Wobblies
I can't find anything new in the USAF research, because you're right: Military pilots don't spend much time on the negative side of the G meter. Dr Mueller's paper (published in the 2002 Ear-Nose-Throat Journal) seems to be the latest article to appear in web searches:
http://mvl.mit.edu/JClub/Spr03/MullerPaper.pdf
Hey, very cool, thanks for checking on it!
I noticed I had more trouble on the push pull type of maneuvers if I held negative G, even as little as -1 negative G, for a longer period of time, say 6 or 7 seconds, and then pulled 4 or more positive G quickly thereafter. A maneuver like a square loop.
On something like an outside snap an a downline, with a pull out, you might hit 4 or 5 negative G in the snap, followed within about 2 to 3 seconds seconds a +6 or +7 G pull. That seemed to be easier to deal with than my first scenario. The snap hurts though, good to know research confirms they suck!
What I would really be interested in would be any further research into "the wobblies" (g induced vestibular dysfunction). There were several theories floating around back in the nineties about why negative G would cause this, and what the causes were, but I don't think there was ever anything definitive. Since we sport aerobatic types are the only ones dumb enough to do this negative stuff regularly, I guess it's not worth the time and money to investigate too thoroughly, and I understand that, but I was curious if there had been anything since what we knew in the nineties about it.
Thanks again,
Damon
I can't find anything new in the USAF research, because you're right: Military pilots don't spend much time on the negative side of the G meter. Dr Mueller's paper (published in the 2002 Ear-Nose-Throat Journal) seems to be the latest article to appear in web searches:
http://mvl.mit.edu/JClub/Spr03/MullerPaper.pdf
N355DW
Well Known Member
Thank you for that link, that was very interesting, I had not read that one. Again, no single cause was identified, but the general routine mentioned in the report for trying to prevent GIVD is pretty much what I remember. I suspect I know the pilot mentioned in the study pretty well, he has had that problem since I met him in 1993. He is a very aggressive pilot, started flying in Advanced almost immediately, and has had problems with the wobblies from day one.
It would be interesting to hear if you guys ever do go back and try some experiments in negative G in the centrifuge. The biggest problem with that of course is I guess a professional pilot could be risking his or her career if the symptoms do not subside!
Thanks again for taking the time on this!
Bugsy
Well Known Member
Two different discussions. One involving spatial disorientaion and the other involving blood shifts with G.
The AF doesnt conduct negative G research because we dont fly in that operational environments. Plus the fact that our centrifuges cant currently replicate a negative G environment.
The mention of different experiences with G exposure of 6-7 sec is very important. With any exposure to Gz negative or possitive. Their are cardovascular responses that occur without you knowing. But these responses take 5-10 seconds to occur. With exposure of pos G your heart rate increases and blood vessals constrict inorder to try to increase venous return. This is why rapid onset of G is actually more worriessome than sllow application of G. Rapid onset can result in low blood flow to brain before the cardiovascular response kicks in.
Damon your short transients to neg G had less of a push pull effect than the longer durations because in the short transients the blood fluid shifts didnt have a chance to progress.
The AF doesnt conduct negative G research because we dont fly in that operational environments. Plus the fact that our centrifuges cant currently replicate a negative G environment.
The mention of different experiences with G exposure of 6-7 sec is very important. With any exposure to Gz negative or possitive. Their are cardovascular responses that occur without you knowing. But these responses take 5-10 seconds to occur. With exposure of pos G your heart rate increases and blood vessals constrict inorder to try to increase venous return. This is why rapid onset of G is actually more worriessome than sllow application of G. Rapid onset can result in low blood flow to brain before the cardiovascular response kicks in.
Damon your short transients to neg G had less of a push pull effect than the longer durations because in the short transients the blood fluid shifts didnt have a chance to progress.
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Bugsy
Well Known Member
With regard to spatial D. Especially the type III incapacitating SD without regard to what induces it the cure is always the same. Unload and keep your head still for 15 sec. The fluid in the semicircular canals will catch up in 15 sec and the otilith effected by G responds even faster.
Spatial D is always agrivated by moving your head in a different plane of motion than the aircraft.
Best cure for motion sickness. Brief your passengers to keep their head still while your maneuvering the aircraft.
Spatial D is always agrivated by moving your head in a different plane of motion than the aircraft.
Best cure for motion sickness. Brief your passengers to keep their head still while your maneuvering the aircraft.
I got nasty wobbles after a hard day of acro (probably with some dehydration).
I leaned into the cockpit after landing to secure the stick and when I stood up the world had tumbled hard.
Stayed tumbled for 2 days. Like that bad nights in the dorms in college.
I finally found some maneuvers on Youtube to reset the inner-ear which gave me virtually instant relief. Amazing. Can't remember the name for it: Nystagmus? or BPV or something.
But if it happened in flight, landing a sporty taildragger would have been tricky. However I think you can do some of these reset maneuvers in the cockpit in emergency (Epley maneuver or something)>
Tj
I leaned into the cockpit after landing to secure the stick and when I stood up the world had tumbled hard.
Stayed tumbled for 2 days. Like that bad nights in the dorms in college.
I finally found some maneuvers on Youtube to reset the inner-ear which gave me virtually instant relief. Amazing. Can't remember the name for it: Nystagmus? or BPV or something.
But if it happened in flight, landing a sporty taildragger would have been tricky. However I think you can do some of these reset maneuvers in the cockpit in emergency (Epley maneuver or something)>
Tj
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