G-forces/women
Dirk McGirk
be able to help me out...
1. What is the maximum G's a person can pull without blacking out?
(trained, using a G suit).
2. After a person G-locks (and the g's stay stable, or increase) will
the person die? (quickly?)
3. Why are women able to cope with G forces better than men? Is it lack
of muscle? More weight in the legs? Better circulation?
4. Whats the maximum speed a person can safey travel without doing
serious harm to their bodies? (G-locking causes burst blood vessels...
Red out anyway... Could this cause a stroke?)
I need to get the science correct for a story... Any help will be
appreciated!
-Dirk
Ron Natalie
Dirk McGirk wrote:
>
> I didn't quite know where to post this question... I hope you guys will
> be able to help me out...
>
> 1. What is the maximum G's a person can pull without blacking out?
> (trained, using a G suit).
Competition aerobatic pilots pull 9+. The F-16 will do about the
same. An average pilot will blackout just under 5. Note that it's
not a hard number, the rate that the G's are applied makes a difference
as well. Military pilots learn g-resistance by gradually increasing
the onset to somewhere between 8 and 15g's. There are roller coasters
in the US that achieve over 6g's.
Since you seem to be writing a space story, note that there are other
factors. The seats in the old space launches are designed to support
the crew in higher G situations.
> 2. After a person G-locks (and the g's stay stable, or increase) will
> the person die? (quickly?)
It's GLOC (no k)...don't know. Of course, if the person is playing a
vital role in keeping th plane aloft, chances are the incapacitation
is going to kill him first.
>
>
> 4. Whats the maximum speed a person can safey travel without doing
> serious harm to their bodies? (G-locking causes burst blood vessels...
> Red out anyway... Could this cause a stroke?)
>
Speed is NOT a factor. Learn the difference between accelleration
(expressed in g's) and velocity. You are also misusing the term
"GLOC". GLOC is g-force induced Loss Of Conciousness (which forms
the acronym LOC in the term). While high g's can cause burst blood
vessels, it's separate from the loc.
Gary Drescher
> 4. Whats the maximum speed a person can safey travel without doing
> serious harm to their bodies? (G-locking causes burst blood
> vessels... Red out anyway... Could this cause a stroke?)
Unless you collide with something, there can't possibly be a speed
that's harmful to travel at, because no physical object is affected in
any way by the speed at which it's moving freely. That's been the most
basic principle of science for the past several hundred years.
> I need to get the science correct for a story... Any help will be
> appreciated!
I think a review of elementary Newtonian mechanics would be important
to help sort out the concepts involved. Good luck with your story!
Sent via Deja.com
http://www.deja.com/
Jim
>
> I need to get the science correct for a story... Any help will be
> appreciated!
Almost all of your questions can be answered in detail (all except for the
difference in Gs women can tolerate) at the following link:
http://avstop.com/AC/AC91-61.html
Thanks for wanting to get it right!
Jim Fisher
North Alabama
Cherokee 180
Kurt R. Todoroff
>be able to help me out...
>
>1. What is the maximum G's a person can pull without blacking out?
>(trained, using a G suit).
It depends on the person's physical condition, what and when they had their
last meal, their mental state, and many other factors.
As a student pilot, I pulled ten Gs in the T-38 to avoid a collision. I
remained fully conscious (thanks to my adrenaline). As an Instructor Pilot, I
lost vision during a four G pull in the F-111. My student did this
unexpectedly while I was looking at the Attack Radar. It depends on ALL of
the circumstances involved during the excursion.
>2. After a person G-locks (and the g's stay stable, or increase) will
>the person die? (quickly?)
G-LOC is an acronym for G induced loss of consciousness. Blood deprivation to
the brain for any extended period of time is dangerous, then fatal. Typically,
the duration of the G excursion in a fighter is not sufficient to cause
physiologic damage.
>3. Why are women able to cope with G forces better than men? Is it lack
>of muscle? More weight in the legs? Better circulation?
I have no data that substantiates this assertion.
>4. Whats the maximum speed a person can safey travel without doing
>serious harm to their bodies? (G-locking causes burst blood vessels...
>Red out anyway... Could this cause a stroke?)
Velocity does not pose a danger to living things. Acceleration, which is the
first order time derivative of velocity, can harm or kill living things, and
damage non-living things.
At this moment, our bodies are traveling at some extremely high velocities
through the solar system, the galaxy, and the universe. I feel fine.
>I need to get the science correct for a story... Any help will be
>appreciated!
>
>-Dirk
Kurt Todoroff
shar...@aol.com
Remove "DELETEME" from my address to reply
Steve Foley
light, mass approaches infinity. That's gotta hurt!!!
"Gary Drescher" <gldre...@my-deja.com> wrote in message
ShawnD2112
hypothesis to any women unless you want to experience FLOC - Female induced
Loss of Conciousness. :)
Shawn
Dirk McGirk wrote in message <3A75BE43...@startrekmail.com>...
Wdtabor
<dirkm...@startrekmail.com> writes:
>
>3. Why are women able to cope with G forces better than men? Is it lack
>of muscle? More weight in the legs? Better circulation?
>
I vaguely remember NASA putting out some information to that effect, but the
context and what you mean by "coping" is important.
Not passing out while sitting in a reclined position is not the same as being
able to perform tasks or move.
For example, if you have ever met any fighter pilots, you might notice that
they have necks like NFL linemen. They have to, a head with a flight helmet on
it weighs an awful lot in a 5 G turn. Fighter pilots who cannot look over their
shoulders while manuevering die.
Your theoretical woman might stay conscious longer sitting still, but few, if
any, have the upper body strength to be competitive as fighter pilots.
So, for us to be of any help, please give us the context.
Don
Wm. Donald (Don) Tabor Jr., DDS
PP-ASEL
Chesapeake, VA - CPK
David CL Francis
Steve Foley <steve.DE...@worldnet.att.net> writes
>I think I learned in high school, that as speed approaches the speed of
>light, mass approaches infinity. That's gotta hurt!!!
No it wouldn't because it is all relative. :-)
--
Francis E-Mail reply to <fli...@dclf.demon.co.uk>
Gary Drescher
"Steve Foley" <steve.DE...@worldnet.att.net> wrote:
> I think I learned in high school that as speed approaches the speed of
> light, mass approaches infinity. That's gotta hurt!!!
Well, I guess it would hurt if it happened in your own intertial
reference frame. Luckily, that's not how it works--you wouldn't notice
any difference at all.
> "Gary Drescher" <gldre...@my-deja.com> wrote in message
> > Unless you collide with something, there can't possibly be a speed
> > that's harmful to travel at, because no physical object is affected
in
> > any way by the speed at which it's moving freely. That's been the
most
> > basic principle of science for the past several hundred years.
>
>
Richie Chapman
> I didn't quite know where to post this question... I hope you guys will
> be able to help me out...
> of muscle? More weight in the legs? Better circulation?
Funnily enough I've just seen a documentary on the Discovery Wings Channel
which touched on this subject. Those of you who do not consider this channel
to be an eminent journal of physiology might well have a point :) Anyway,
they said that women can handle g forces better than men because they are on
average shorter.
Viperdoc
applied g, often referred to g"z", g"x", G"y" (can't figure out how to
do subscripts here).
I forget the orientation of the axes, but you can tolerate a lot more
positive g when it's applied when you're laying down as compared to
sitting up.
Also, conditioning and acclimatization make a big difference. At the
beginning of the aerobatic season I have difficulty with 4 G's, but
after a few flights it becomes easier to tolerate +7 to -5 on a regular
basis.
The feel of G forces in high performance fighters is entirely different,
since I've also had the opportunity to get a fair amount of time in
F-16's. Here it becomes raw power and strength to resist the prolonged
(up to 30 secs) of 8 and occasionally 9 g. The g suit helps a little, as
does some added stuff called combat edge, but not a huge amount.
In aerobatics the g forces come up quicker, but are a lot shorter in
duration and much easier to tolerate. Also, flying acro can involve
rapid transitions from -5 to plus 7 g, which is a net change of 12 g!
I've never experienced gloc, but in our centrifuge ride several people
did. In my opinion as a flight surgeon, prolonged high g without the
benefit of a recovery starves the brain of blood and oxygen, which is
why people who gloc jerk around doing the "funky chicken". Ultimately
this probably would be fatal, except that you're likely to drive into
the ground before that happens.
Short muscular people can tolerate g better than tall lanky people. This
is felt to simply be a function of the distance between your heart and
head and the pressure required to keep your brain perfused.
I will always remember our centrifuge ride. The first guy threw up
violently with all of us watching on the TV monitor, and the person just
before me gloced and his heart slowed down and ultimately stopped! There
were a lot of sirens and flashing red lights going off for a while, but
he rapidly awoke and described the pleasant dreams he had been
experiencing (a common occurence during gloc). Luckily I passed the ride
without difficulty, although I had a sore neck for a few days. Having
had some acro experience was a big asset.
Good luck on your study.
Seth Masia
it takes to pump blood uphill against a 5 or 6G pull. Might want to ask
Patty Wagstaff about this. I've also been told that marathoners and other
highly conditioned athletes make poor aerobatic candidates, because their
blood pressure is consistently low -- too low to supply the brain at
elevated G.
se...@masia.org
N8100R
"Viperdoc" <jni...@attglobal.net> wrote in message
news:3A76100F...@attglobal.net...
GKgloc
Good answers. If you're a FS for the USAF, I'm assuming you trained in the
GLAB centrifuge at Holloman AFB. I've also ridden that centrifuge. Actually
the company I work for (ETC) built that centrifuge, and several others. Most
recently, I've ridden the centrifuges at NAS Lemoore, RSAF Singapore, TUAF
Eskisher Turkey, and JDA Japan.
I'm most interested in hearing about you'rs and other's centrifuge experiences.
If anyone has any, please post them.
Oh, to clairfy the thread on what the most speed that one can endure, it's
actually the G-onset or offset rate that leads to GLOC. Most modern
centrifuges can produce upwards of 10 -15 Gsec onset rate (acceleration), the
one at Holloman is only capable of 6G/sec, while the one in Singapore is
capable of 10 Gsec.
If anyone is interested in learning more about the physiological effects of a
high-G environment, please feel free to visit our website at etcusa.com, or you
can email me directly. Sorry, but I'm not allowed to offer centrifuge rides.
But if you're visiting the Southampton PA area, feel free to give me a call,
I'll give you a plant tour and show you the latest centrifuge we're building
(sorry can't release customer's name), but it's a 15G onset machine, with a max
G level of 25G. Whatta ride!
Blue skies....
Glenn King
Environmental Tectonics Corporation
Aircrew Training Systems
Application Manager