Re: How indicative of agility are max G numbers?

[Anonymous]

Hobo wrote in message ...
>
>
>How indicative of maneaverability are the max G numbers of fighter
>aircraft?
>
>Also, most new aircraft have reported max of 9Gs. Why are they all
>coming out at this same number?

Modern aircraft are capable of higher G turns; however, in order to
stop the pilots from blacking/redding out and/or dying in their
seat, the computer controlling the fly-by-wire / fly-by-light
systems stops the turns going any higher.

I think :)

Cheers
Graeme

[Mark Irvine]

"Anonymous" > wrote in message
...
>
> Hobo wrote in message ...
> >
> >
> >How indicative of maneaverability are the max G numbers of fighter
> >aircraft?
> >
> >Also, most new aircraft have reported max of 9Gs. Why are they all
> >coming out at this same number?
>
> Modern aircraft are capable of higher G turns; however, in order to
> stop the pilots from blacking/redding out and/or dying in their
> seat, the computer controlling the fly-by-wire / fly-by-light
> systems stops the turns going any higher.
>
> I think :)
>
> Cheers
> Graeme
>
>
It could also be because they do not want to release into the public domain
the exact performance of the aircraft? A few years ago all aircraft seemed
to be listed as Mach 2.2 at altitude??

Mark

[[email protected]]

Modern G-suits allow much higher G-forces, so the pilot should not be the
limiting factor.

"Mark Irvine" > wrote in message
...
>
> "Anonymous" > wrote in message
> ...
> >
> > Hobo wrote in message ...
> > >
> > >
> > >How indicative of maneaverability are the max G numbers of fighter
> > >aircraft?
> > >
> > >Also, most new aircraft have reported max of 9Gs. Why are they all
> > >coming out at this same number?
> >
> > Modern aircraft are capable of higher G turns; however, in order to
> > stop the pilots from blacking/redding out and/or dying in their
> > seat, the computer controlling the fly-by-wire / fly-by-light
> > systems stops the turns going any higher.
> >
> > I think :)
> >
> > Cheers
> > Graeme
> >
> >
> It could also be because they do not want to release into the public
domain
> the exact performance of the aircraft? A few years ago all aircraft
seemed
> to be listed as Mach 2.2 at altitude??
>
> Mark
>
>

[Dudley Henriques]

"Hobo" > wrote in message
...
>
>
> How indicative of maneaverability are the max G numbers of fighter
> aircraft?

You can pull max g all the way out to the structural limits of the
airframe.....but at what turn rate?.....radius? And where does that put you
in relation to the adversary? (Delta Ps)
In order to determine maneuverability, the g ability to pull g has to be
married into an overall performance graph; then this graph must be compared
to other aircraft. You can't just use one specific to determine a fighter's
performance, or ability to maneuver. It takes the integration of many
different factors, all interfaced into the flight envelope to determine
maneuverability. The ability to pull g is inherent in every
fighter......what you do with that g, and WHERE in the envelope you pull
that g are much more pertinent to maneuverability than the fact that you CAN
pull g.
Then, after you determine all this, there's roll rate, stability, axis
coupling limits, and a whole slew of other good stuff to feed into the
equation.
It's a complicated process. G, and the ability to pull g, are simply factors
in this HUGE overall process of determining maneuverability.
Hope this helps a bit.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

[Mark Irvine]

mmm, not so sure, the physiology of the human body is such that the brain
needs that blood! While modern G suits help to limit the surge of blood to
the feet they cannot totally stop it. Also the human head head weighs
around 4 - 5 kg. At 9 G the effective weight is 36 - 45 kg. That does not
take into account the additional weight of the helmet. That is some load
through the neck, come to think of it is is like 1/2 of me being on my own
head with no support, ouch...

I still think that the human is the limiting factor.

Mark



> wrote in message
...
> Modern G-suits allow much higher G-forces, so the pilot should not be the
> limiting factor.
>
> "Mark Irvine" > wrote in message
> ...
> >
> > "Anonymous" > wrote in message
> > ...
> > >
> > > Hobo wrote in message ...
> > > >
> > > >
> > > >How indicative of maneaverability are the max G numbers of fighter
> > > >aircraft?
> > > >
> > > >Also, most new aircraft have reported max of 9Gs. Why are they all
> > > >coming out at this same number?
> > >
> > > Modern aircraft are capable of higher G turns; however, in order to
> > > stop the pilots from blacking/redding out and/or dying in their
> > > seat, the computer controlling the fly-by-wire / fly-by-light
> > > systems stops the turns going any higher.
> > >
> > > I think :)
> > >
> > > Cheers
> > > Graeme
> > >
> > >
> > It could also be because they do not want to release into the public
> domain
> > the exact performance of the aircraft? A few years ago all aircraft
> seemed
> > to be listed as Mach 2.2 at altitude??
> >
> > Mark
> >
> >
>
>

[Ken Duffey]

Mark Irvine wrote:

> mmm, not so sure, the physiology of the human body is such that the brain
> needs that blood! While modern G suits help to limit the surge of blood to
> the feet they cannot totally stop it. Also the human head head weighs
> around 4 - 5 kg. At 9 G the effective weight is 36 - 45 kg. That does not
> take into account the additional weight of the helmet. That is some load
> through the neck, come to think of it is is like 1/2 of me being on my own
> head with no support, ouch...
>
> I still think that the human is the limiting factor.
>
> Mark

Snip......

Interestingly, the Russians have a different approach - instead of trying to
make the systems cope with the G stresses, they tend to select squat, fit men -
and then train them to tolerate G, rather than trying to have systems (G-suits,
cockpit environment etc) that try to cater for all body sizes.

In other words - start with the best bodies - then add the systems.

During a visit to Kubinka, near Moscow, (the home of the Russian aerobatic
teams - the Russian Knights and the Swifts) in 1993, they told us that during a
visit by the Blue Angels they swapped back-seat rides in F/A-18's and Su-27's &
MiG-29's.

The US Navy pilots (who are no slouches!) were amazed at the Russian pilot's
ability to tolerate high-G forces.

In fact they (the Russian pilots) pointed to one of their number (a short,
bull-necked, squat, MiG-29/ Swifts pilot) and said that he held the squadron
record at 11G - and this was a regular occurrence !

They also laughingly stated that when he joined the squadron he was over six
feet tall !!

(They also pointed to another pilot who had a large hook nose - and said that
he was a parrot rather than a swift !!! - they had a great sense of humour).

Also - wasn't there a discussion on this NG some time ago about the ability of
females to tolerate highr G forces than men ?? Something to do with their
physiology (lower centre of gravity ??)

Or am I opening up a whole new can of worms ??

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++
Ken Duffey - Flanker Freak & Russian Aviation Enthusiast
Flankers Website - http://www.flankers.co.uk/
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++

[Dudley Henriques]

"Ken Duffey" > wrote in message
...
> Mark Irvine wrote:
>
> > mmm, not so sure, the physiology of the human body is such that the
brain
> > needs that blood! While modern G suits help to limit the surge of blood
to
> > the feet they cannot totally stop it. Also the human head head weighs
> > around 4 - 5 kg. At 9 G the effective weight is 36 - 45 kg. That does
not
> > take into account the additional weight of the helmet. That is some
load
> > through the neck, come to think of it is is like 1/2 of me being on my
own
> > head with no support, ouch...
> >
> > I still think that the human is the limiting factor.
> >
> > Mark
>
> Snip......
>
> Interestingly, the Russians have a different approach - instead of trying
to
> make the systems cope with the G stresses, they tend to select squat, fit
men -
> and then train them to tolerate G, rather than trying to have systems
(G-suits,
> cockpit environment etc) that try to cater for all body sizes.
>
> In other words - start with the best bodies - then add the systems.
>
> During a visit to Kubinka, near Moscow, (the home of the Russian aerobatic
> teams - the Russian Knights and the Swifts) in 1993, they told us that
during a
> visit by the Blue Angels they swapped back-seat rides in F/A-18's and
Su-27's &
> MiG-29's.
>
> The US Navy pilots (who are no slouches!) were amazed at the Russian
pilot's
> ability to tolerate high-G forces.
>
> In fact they (the Russian pilots) pointed to one of their number (a short,
> bull-necked, squat, MiG-29/ Swifts pilot) and said that he held the
squadron
> record at 11G - and this was a regular occurrence !
>
> They also laughingly stated that when he joined the squadron he was over
six
> feet tall !!
>
> (They also pointed to another pilot who had a large hook nose - and said
that
> he was a parrot rather than a swift !!! - they had a great sense of
humour).
>
> Also - wasn't there a discussion on this NG some time ago about the
ability of
> females to tolerate highr G forces than men ?? Something to do with their
> physiology (lower centre of gravity ??)
>
> Or am I opening up a whole new can of worms ??

This is true. The Blues trip was enjoyable. A lot of friendships were made
that endure to this day.
As for the Russians approach to g; it's very important to differentiate
between instantaneous and sustained g when talking tolerance. They know this
as well as we do, and regardless of body frame, they know when to call it a
day.
There's a time line involved. We generally consider +9 with a suit and
strain to be about it for useful fighter purposes. You can really get into
trouble if you push this too far. It's called the 9g sleep! In fact, pilots
who aren't in superb physical condition can easily get into an unrecoverable
situation if pushing +9 along the Gz axis on any consistent basis.
When I was flying demonstrations I was in great shape for just these
reasons. I would routinely hit +9 instantaneous when doing multiple snap
rolls in the Pitts with no noticeable effect during or after, but I was
always careful with sustained g over +6. In the 51, I never used over +4
sustained and never anything instantaneous.
Flying something like the F16 or the Flanker is a whole different ballgame
with g. These airplanes can deliver more than you can handle unless you're
EXTREMELY careful. You can literally kill yourself in these airplanes if you
go around playing with sustained 11g's! Most pilots who fly these aircraft
are on a continuous physical conditioning program, and ALL know the
ramifications of pushing too far into the available g. You have good
days....and you have bad days for pushing this kind of sustained g. It's up
to each pilot to know his condition on any given day and keep the numbers in
line for how he's measuring up physically on that specific flight. In an F16
or a Flanker, you can have a late night at the O club, fly an ACM practice
mission the next morning at 8:30 and be dead by 9am.
Bottom line....don't get too fired up about the Russians "squat" pilots! It
might work for an individual who's in line with everything else involved,
but as a general thing just considering physical makeup......."it don't mean
squat" :-)
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

[monkey]

"Dudley Henriques" > wrote in message . net>...
> "Hobo" > wrote in message
> ...
> >
> >
> > How indicative of maneaverability are the max G numbers of fighter
> > aircraft?
>
> You can pull max g all the way out to the structural limits of the
> airframe.....but at what turn rate?.....radius? And where does that put you
> in relation to the adversary? (Delta Ps)
> In order to determine maneuverability, the g ability to pull g has to be
> married into an overall performance graph; then this graph must be compared
> to other aircraft. You can't just use one specific to determine a fighter's
> performance, or ability to maneuver. It takes the integration of many
> different factors, all interfaced into the flight envelope to determine
> maneuverability. The ability to pull g is inherent in every
> fighter......what you do with that g, and WHERE in the envelope you pull
> that g are much more pertinent to maneuverability than the fact that you CAN
> pull g.
> Then, after you determine all this, there's roll rate, stability, axis
> coupling limits, and a whole slew of other good stuff to feed into the
> equation.
> It's a complicated process. G, and the ability to pull g, are simply factors
> in this HUGE overall process of determining maneuverability.
> Hope this helps a bit.
> Dudley Henriques
> International Fighter Pilots Fellowship
> Commercial Pilot/ CFI Retired
> For personal email, please replace
> the z's with e's.
> dhenriquesATzarthlinkDOTnzt

G is not really important from a tactical perspective, what is
important in a turning engagement is turn rate or turn radius; which
of these should be maximized depends on the situation (eg defensive,
offensive, 2 vs 1 circle fight). I won't get into the specifics except
to state that g is not a very significant measure of fighter
performance.

monkey
canadian fighter pilot

[Dudley Henriques]

"monkey" > wrote in message
om...
> "Dudley Henriques" > wrote in message
. net>...
> > "Hobo" > wrote in message
> > ...
> > >
> > >
> > > How indicative of maneaverability are the max G numbers of fighter
> > > aircraft?
> >
> > You can pull max g all the way out to the structural limits of the
> > airframe.....but at what turn rate?.....radius? And where does that put
you
> > in relation to the adversary? (Delta Ps)
> > In order to determine maneuverability, the g ability to pull g has to be
> > married into an overall performance graph; then this graph must be
compared
> > to other aircraft. You can't just use one specific to determine a
fighter's
> > performance, or ability to maneuver. It takes the integration of many
> > different factors, all interfaced into the flight envelope to determine
> > maneuverability. The ability to pull g is inherent in every
> > fighter......what you do with that g, and WHERE in the envelope you pull
> > that g are much more pertinent to maneuverability than the fact that you
CAN
> > pull g.
> > Then, after you determine all this, there's roll rate, stability, axis
> > coupling limits, and a whole slew of other good stuff to feed into the
> > equation.
> > It's a complicated process. G, and the ability to pull g, are simply
factors
> > in this HUGE overall process of determining maneuverability.
> > Hope this helps a bit.
> > Dudley Henriques
> > International Fighter Pilots Fellowship
> > Commercial Pilot/ CFI Retired
> > For personal email, please replace
> > the z's with e's.
> > dhenriquesATzarthlinkDOTnzt
>
> G is not really important from a tactical perspective, what is
> important in a turning engagement is turn rate or turn radius; which
> of these should be maximized depends on the situation (eg defensive,
> offensive, 2 vs 1 circle fight). I won't get into the specifics except
> to state that g is not a very significant measure of fighter
> performance.
>
> monkey
> canadian fighter pilot

I can't tell if you are trying to add to what I said, or trying to correct
what I've said in some way? From what I'm reading, I believe what you are
saying is EXACTLY what I just said....which is correct!
:-)
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

[Yeff]

On Thu, 20 Nov 2003 19:19:12 GMT, Dudley Henriques wrote:

> Flying something like the F16 or the Flanker is a whole different ballgame
> with g. These airplanes can deliver more than you can handle unless you're
> EXTREMELY careful.

I remember seeing some video taken in an F-16B (I believe). It was a
student and instructor pilot who'd just done a loop and the student went to
sleep. You can see the Viper heading towards the ground with the
instructor calmly saying over and over, "Recover. Recover." I guess he
finally takes the stick and pulls up. Made the hair on the back of my neck
stand up.

-Jeff B.
yeff at erols dot com

[Dudley Henriques]

"Yeff" > wrote in message
...
> On Thu, 20 Nov 2003 19:19:12 GMT, Dudley Henriques wrote:
>
> > Flying something like the F16 or the Flanker is a whole different
ballgame
> > with g. These airplanes can deliver more than you can handle unless
you're
> > EXTREMELY careful.
>
> I remember seeing some video taken in an F-16B (I believe). It was a
> student and instructor pilot who'd just done a loop and the student went
to
> sleep. You can see the Viper heading towards the ground with the
> instructor calmly saying over and over, "Recover. Recover." I guess he
> finally takes the stick and pulls up. Made the hair on the back of my
neck
> stand up.
>
> -Jeff B.
> yeff at erols dot com

Yup. We used that clip in safety meetings more than once.
It pays to be in shape!!
DH

[WaltBJ]

There's a mix here involved. Max G available, G onset (how fast can
you load it up) and corner velocity - the minimum speed do you need to
generate the lift necessary attain max G. A lot of limitations pop up
now. Higher the G, teh stronger tha irplane must be, and therefore the
weight goes up, so the wing has to be bigger. Also to sustain the G
you need more thrust because induced drag (drag due to generating
lift) goes sky-high.
Generally the design working G limit has been either 7 1/2 or 9 - and
with a 50% safety factor that means the structural yield limit ( bent
and won't 'unbend' either 11 1/4 or 13.5 G. Human G tolerance depends
a great deal on training fitness and 'want to'. I have seen 10.5 on a
G-meter whena student 'dug in' an F4 decelerating through the Mach -
my forward push stopped it from going even higher. My G tolerance came
from flying the F102 sans G-suit and hasseling with anything that came
along. It could pull 3G at 200 KIAS, 7G at about 325, though not for
long (delta wing at airspeed!) FWIW I have a friend who was conscious
and talking to the doctors on USC's centrifuge at 11 G sustained. He
is about 6-2 and 180. Also, I know of two incidents were the pilots
recovered their aircraft pulling 12 (F106) and 13 G (F86D)
respectively after getting the nose buried close to the ground. Yes,
the aircraft were severely bent, but the pilots survived. Adrenalin is
a wonder drug in these cases - special cases of 'want to'.
Walt BJ

[Dudley Henriques]

"WaltBJ" > wrote in message
om...
> There's a mix here involved. Max G available, G onset (how fast can
> you load it up) and corner velocity - the minimum speed do you need to
> generate the lift necessary attain max G. A lot of limitations pop up
> now. Higher the G, teh stronger tha irplane must be, and therefore the
> weight goes up, so the wing has to be bigger. Also to sustain the G
> you need more thrust because induced drag (drag due to generating
> lift) goes sky-high.
> Generally the design working G limit has been either 7 1/2 or 9 - and
> with a 50% safety factor that means the structural yield limit ( bent
> and won't 'unbend' either 11 1/4 or 13.5 G. Human G tolerance depends
> a great deal on training fitness and 'want to'. I have seen 10.5 on a
> G-meter whena student 'dug in' an F4 decelerating through the Mach -
> my forward push stopped it from going even higher. My G tolerance came
> from flying the F102 sans G-suit and hasseling with anything that came
> along. It could pull 3G at 200 KIAS, 7G at about 325, though not for
> long (delta wing at airspeed!) FWIW I have a friend who was conscious
> and talking to the doctors on USC's centrifuge at 11 G sustained. He
> is about 6-2 and 180. Also, I know of two incidents were the pilots
> recovered their aircraft pulling 12 (F106) and 13 G (F86D)
> respectively after getting the nose buried close to the ground. Yes,
> the aircraft were severely bent, but the pilots survived. Adrenalin is
> a wonder drug in these cases - special cases of 'want to'.
> Walt BJ

Yeah, it's a multiples thing all right, especially if you throw corner in
there . Below corner you're aerodynamically limited and above you're
structurally limited; go high enough and you're thrust limited as well......
but just considering g alone which was his question, and forgetting rate and
radius, you can pull max g all the way out to the right side of the envelope
until either you or the airplane starts complaining :-)
But I agree with you. You can't even begin to discuss fighter performance
using a one aspect only condition. There's just too much involved, and the
whole thing has to be integrated into the discussion for anything to make
sense at all.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

[Ed Rasimus]

On Fri, 21 Nov 2003 04:47:47 GMT, "Dudley Henriques"
> wrote:

>
>"WaltBJ" > wrote in message
om...
>> There's a mix here involved. Max G available, G onset (how fast can
>> you load it up) and corner velocity - the minimum speed do you need to
>> generate the lift necessary attain max G. --snip--
>> Walt BJ
>
>Yeah, it's a multiples thing all right, especially if you throw corner in
>there . Below corner you're aerodynamically limited and above you're
>structurally limited; go high enough and you're thrust limited as well......
>but just considering g alone which was his question, and forgetting rate and
>radius, you can pull max g all the way out to the right side of the envelope
>until either you or the airplane starts complaining :-)
> But I agree with you. You can't even begin to discuss fighter performance
>using a one aspect only condition. There's just too much involved, and the
>whole thing has to be integrated into the discussion for anything to make
>sense at all.
>Dudley Henriques

I was going to jump into this yesterday, but delayed and "lo" I've
developed insight. I was going to dump my usual tirade about tactics,
training, weapons, mutual support, etc. Then, I returned to the
question.

It isn't about "fighter", it's about agility. "How indicative of
agility are max G numbers?"

I'd have to say, only minimally indicative. The 105 had a max positive
G of 8.67--a structure limit which was virtually impossible to attain,
except instantaneously. Airspeed bleedoff, if you get anywhere up to
those kinds of numbers meant you couldn't sustain for long at all.

The F-4, conversely had a 7.33 max, much lower, but no one will
challenge that the F-4 had greater agility than a 'Chief.

Clearly there's a "critical mass" sort of minimum G required to get
you into the A/A game. You don't go hassling with a 2.5 G limit MiG-25
even though you have weapons, thrust and airspeed. Corner velocity is
a consideration, attainable onset rates, sustainable G-loads,
rate/radius numbers, roll rates, all are players.

And, who can quantify that elusive "experience" factor. Doing
instructor continuation training in AT-38s at Fighter Lead-In, I
couldn't begin to pull the sustained G while twisted around in my seat
looking at my own rudder, but I could get the "big picture" of where
the battle was going and kick the young guys' butts at much lower G.

Sort of the old and young bull metaphor---young bull sees the herd and
says "lets run down and screw one." The old bull says, "lets walk down
and screw them all."

[José Herculano]

> Generally the design working G limit has been either 7 1/2 or 9 - and
> with a 50% safety factor that means the structural yield limit ( bent
> and won't 'unbend' either 11 1/4 or 13.5 G. Human G tolerance depends

Great post, as usual, Walt. My favourite present day example is the F/A-18.
It is limited by the FCS to 7.5 G, but it maneuvers like a SOB!
_____________
José Herculano

[vincent p. norris]

>How indicative of maneaverability are the max G numbers of fighter
>aircraft?

If your measure of "maneuverability" is the radius of the airplane's
circle, the anwer is No. A Sopwith Pup could turn a very tight circle
while pulling very few Gs.

I realize you were no doubt thinking of modern fighters when you asked
the question, but the above example should tell you something about
agility and Gs.

vince norris

[Paul F Austin]

"Mark Irvine" wrote
>
> "Anonymous" wrote
> >
> > Hobo wrote in message ...
> > >
> > >
> > >How indicative of maneaverability are the max G numbers of fighter
> > >aircraft?
> > >
> > >Also, most new aircraft have reported max of 9Gs. Why are they all
> > >coming out at this same number?
> >
> > Modern aircraft are capable of higher G turns; however, in order to
> > stop the pilots from blacking/redding out and/or dying in their
> > seat, the computer controlling the fly-by-wire / fly-by-light
> > systems stops the turns going any higher.
> >
> > I think :)
> >
> > Cheers
> > Graeme
> >
> >
> It could also be because they do not want to release into the public
domain
> the exact performance of the aircraft? A few years ago all aircraft
seemed
> to be listed as Mach 2.2 at altitude??

There are real physiological limits for piloted aircraft and "9G" designs
press that limit. Designing an airframe to greatly exceed the limits of the
wet-ware controller means that you are carrying structure that you will
never use. Unpiloted aircraft of course don't have that limitation, so
expect UCAVs to open that number up.

As far as Mach 2.2 is concerned, that number comes from the stagnation
temperature associated with the Mach number and the fact that most of the
fighters of that generation were aluminum. Aluminum airplanes get soft when
they dwell above M2.2 or so. Composites have better high temperature
characteristics than do Aluminum based alloys so if there is
a_requirement_for operation at higher Mach numbers then it's technically
possible to do so. Apparently there_is_no requirement, rather there is a
requirement for supersonic persistence in the M1.5 or so speed range.

[Nele_VII]

Mr. Rasimus,

MiG-25 has >sustained< 5g limit with half fuel stated in every source I've
ever seen. Where did You get 2.5g? That was a limit for A-12/SR71 Blackbird.

Also, I have read article in which test pilot states that one MiG-25 went to
10.5g(!), the MiG-25 airframe got deformed but landed safely.

Maybe Mr. Cooper knows better than I do?

--

Nele

NULLA ROSA SINE SPINA
Ed Rasimus wrote in message ...
>On Fri, 21 Nov 2003 04:47:47 GMT, "Dudley Henriques"
> wrote:
>
<snip>
>I was going to jump into this yesterday, but delayed and "lo" I've
>developed insight. I was going to dump my usual tirade about tactics,
>training, weapons, mutual support, etc. Then, I returned to the
>question.
>
>It isn't about "fighter", it's about agility. "How indicative of
>agility are max G numbers?"
>
>I'd have to say, only minimally indicative. The 105 had a max positive
>G of 8.67--a structure limit which was virtually impossible to attain,
>except instantaneously. Airspeed bleedoff, if you get anywhere up to
>those kinds of numbers meant you couldn't sustain for long at all.
>
>The F-4, conversely had a 7.33 max, much lower, but no one will
>challenge that the F-4 had greater agility than a 'Chief.
>
>Clearly there's a "critical mass" sort of minimum G required to get
>you into the A/A game. You don't go hassling with a 2.5 G limit MiG-25
>even though you have weapons, thrust and airspeed. Corner velocity is
>a consideration, attainable onset rates, sustainable G-loads,
>rate/radius numbers, roll rates, all are players.
>
>And, who can quantify that elusive "experience" factor. Doing
>instructor continuation training in AT-38s at Fighter Lead-In, I
>couldn't begin to pull the sustained G while twisted around in my seat
>looking at my own rudder, but I could get the "big picture" of where
>the battle was going and kick the young guys' butts at much lower G.
>
>Sort of the old and young bull metaphor---young bull sees the herd and
>says "lets run down and screw one." The old bull says, "lets walk down
>and screw them all."
>
>

[John Carrier]

> How indicative of maneaverability are the max G numbers of fighter
> aircraft?

Somewhat. Of course the A-4 Superfox (A-4F with J-52P408 and stripped of
humpback et al) was an aluminum assassin in the adversary role and rarely
exceeded 6G.

> Also, most new aircraft have reported max of 9Gs. Why are they all
> coming out at this same number?

Structural design starts getting to be a small problem above 9G (which
implies 13.5G prior to overload), but 9G is about it from the operator
standpoint. You can endure more for a short while, but not while performing
actions other than enduring the G. Even the fittest of the Viper drivers
don't pull max G for long periods.

R/ John

[WaltBJ]

A section of the videotape of the Paris Airshow of (around) 1987 or so
includes the HUD display of an F16 flown by a company demo pilot. You
can hear him grunting to combat the G forces as he pulls up to 9G (all
the way around a 360 turn). You can also hear him sigh in relief as he
plants the thing on the ground after his workout. (It's the airshow
where the MiG29 does a lawn-dart.)
Pulling G like that is work. Doing it for three missions a day is hard
work. Doing it without a G-suit is bloody hard work!
Walt BJ

[Juvat]

After an exhausting session with Victoria's Secret Police, John
Carrier blurted out:

>Structural design starts getting to be a small problem above 9G (which
>implies 13.5G prior to overload), but 9G is about it from the operator
>standpoint. You can endure more for a short while, but not while performing
>actions other than enduring the G. Even the fittest of the Viper drivers
>don't pull max G for long periods.

Down at the centrifuge at Brooks AFB, they had a picture of a gal that
had the "honor" of receiving the "elephant award." She held the record
for 15 Gs and not going to sleep, 15Gs was computed to be the
equivalent of having an elephant stand on your chest.

They also showed a video of a viper guy spinning at 9 Gs carrying on a
simulated air-to-air dialog...this guy was a squatty body.

The day before I got to ride the spin-n-puke, two FWS F-16 IPs both
went to sleep during their rides. Too much fun in San Antonio the
night prior.

Pulling 9 Gs was the least favorite part of the FCF profile for me.
Few years back (10 away from the F-16) I was surprised that 3-4 Gs in
a T-6G felt "heavy."

Juvat