How indicative of agility are max G numbers?

"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

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

"Mark Irvine" wrote in message
news

"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

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
news

"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

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/
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++

"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

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

"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

"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.