Turning performance of SEA fighters

John Carrier wrote:

snip

Generally, the sustained turn rate was around 14-15 degrees/second for
the F-4 hard-wing and about 12.5-13.5 for the F-105.

Don't know where you got these numbers, but sustained for the F-4 was under
10 degrees/sec at combat altitudes and weights (we typically used 15K, 4+4,
no tanks, and 60% fuel) and was found at around 450 KIAS.

For reasons known only to the services, the USN standard for 'combat' weight is
with 60% fuel, while the USAF uses 50%.

The F-8 could do
just under 11 degrees/sec @ 400 in similar conditions (better wing, less
wing loading, not much less T/W). ... roughly a 1 degree/sec advantage. Of
course the Mig-21 (the adversary we trained for) was a couple better than
that. Still looking at under 15 degree/sec sustained.

snip

I've got one source which gives 14 deg./sec. sustained for the F-15A, 16 deg.
instantaneous. The same source claims it can sustain 7.3g at 400 kts/15kft;
it's unclear if that's KTAS or KCAS, but I'm guessing the latter. It credits
the F-5E with slightly over 11 deg. sec. sustained -- IIRC corner for it is
around 375 or so. ISTR seeing the F-16A credited with ca. 16 deg./sec.
sustained. BTW, John, I've read that the (hard-wing) F-4 could generally beat
the F-8 at low/medium altitude (once the pilots learned to use its energy
advantage), but at high altitudes the F-8's lower drag (induced, parasitic
and/or wave) gave it the advantage. What's your take?

Guy

snip

I've got one source which gives 14 deg./sec. sustained for the F-15A, 16
deg.
instantaneous. The same source claims it can sustain 7.3g at 400
kts/15kft;
it's unclear if that's KTAS or KCAS, but I'm guessing the latter. It
credits
the F-5E with slightly over 11 deg. sec. sustained -- IIRC corner for it
is
around 375 or so. ISTR seeing the F-16A credited with ca. 16 deg./sec.
sustained. BTW, John, I've read that the (hard-wing) F-4 could generally
beat
the F-8 at low/medium altitude (once the pilots learned to use its energy
advantage), but at high altitudes the F-8's lower drag (induced, parasitic
and/or wave) gave it the advantage. What's your take?

Pretty good numbers, I think.

As to the F-8 versus F-4, you presented the prevailing conventional wisdom
of the time. When I was an F-8 guy, I felt I pretty much could have the
Phantom for lunch. But there was a time or two when the individual I
opposed transformed the jet into a serious adversary, "Who IS that guy?"

The F-8 had superior PsubS under G than the Phantom at altitudes above
15,000 feet, so any kind of classic turning fight (oblique loop, etc was the
thing in the tacmans at the time) played to its advantage. The Phantom was
more controllable very slow and enjoyed superior unloaded acceleration.
That points to a VERY vertical fight.

When I finally transitioned to the F-4, I thought, "No wonder it was so easy
to beat up on this jet." But, by the 500 hour mark I had changed to, "How'd
we EVER beat up on this jet?" The F-4 was the antithesis of the
point-and-pull fighter and required a great deal of finesse to fight well
(skills that many never achieved IMO). Once mastered, you could
successfully engage just about any aircraft of its generation ... albeit a
roller with a Mig-17 was ill-advised (hear that, Duke?). Of course, once
the next generation appeared (F-14 and subsequent), there really wasn't
anyplace to take the fight they couldn't go.

R / John

My F-5E chart for 5000'MSL (50% fuel, 2 AIM-9) gives a 7g corner at about
365KCAS and a sustained 7g capability at about 600KCAS for a rate of just
under 12dps. That's really honkin' for this jet...a more realistic sustained
value is about 9.5dps at 430KCAS...the curve wanders a bit, but that works
out as around 4.5g or so.
"Guy Alcala" wrote in message
. ..
John Carrier wrote:

snip

Generally, the sustained turn rate was around 14-15 degrees/second for
the F-4 hard-wing and about 12.5-13.5 for the F-105.

Don't know where you got these numbers, but sustained for the F-4 was
under
10 degrees/sec at combat altitudes and weights (we typically used 15K,
4+4,
no tanks, and 60% fuel) and was found at around 450 KIAS.

For reasons known only to the services, the USN standard for 'combat'
weight is
with 60% fuel, while the USAF uses 50%.

The F-8 could do
just under 11 degrees/sec @ 400 in similar conditions (better wing, less
wing loading, not much less T/W). ... roughly a 1 degree/sec advantage.
Of
course the Mig-21 (the adversary we trained for) was a couple better
than
that. Still looking at under 15 degree/sec sustained.

snip

I've got one source which gives 14 deg./sec. sustained for the F-15A, 16
deg.
instantaneous. The same source claims it can sustain 7.3g at 400
kts/15kft;
it's unclear if that's KTAS or KCAS, but I'm guessing the latter. It
credits
the F-5E with slightly over 11 deg. sec. sustained -- IIRC corner for it
is
around 375 or so. ISTR seeing the F-16A credited with ca. 16 deg./sec.
sustained. BTW, John, I've read that the (hard-wing) F-4 could generally
beat
the F-8 at low/medium altitude (once the pilots learned to use its energy
advantage), but at high altitudes the F-8's lower drag (induced, parasitic
and/or wave) gave it the advantage. What's your take?

Guy

On Sat, 14 Aug 2004 23:45:17 GMT, Guy Alcala
wrote:

John Carrier wrote:

Generally, the sustained turn rate was around 14-15 degrees/second for
the F-4 hard-wing and about 12.5-13.5 for the F-105.

H'mm, those numbers seem kind of high for both, as far as sustained
capability
goes.

400 KTAS, turn rate in Deg./sec. (rounded off) = 19 (7g); 22 (8g).

500KTAS, turn rate in Deg./sec. (rounded off) = 15 (7g); 17 (8g); 20 (9g).

600KTAS, turn rate in Deg./sec. (rounded off) = 13(7g); 14 (8g); 16 (9g).

I'm missing something here. You say the numbers are high and then offer
higher numbers. Or are these just basic computations of turn rates w/o
regard to airframe factors?

snip

Yes. I wanted to show what the maximum turn rate was for the various KTAS/g
combinations; sustained would be less.

Guy

I woke in the middle of the night thinking about this discussion--I
know, it indicates some level of neuroses....

I've said that KIAS not True Air Speed is the relevant number, you
indicate a desire to relate G available and hence turning performance
to KTAS.

Consider this. At low altitude, true air speed can be quite close to
indicated. It will always be higher than indicated, but not
exceptionally higher. So, if you are running around at corner velocity
(always expressed in KIAS) of say 420 KIAS, you might be at 475 KTAS
and you could pull max allowable G.

Now, move the airplane up to FL450 and establish the same 475 KTAS
condition. Ooopps! You're cruising around at something less than 300
KIAS (don't dissect the number, it's an approximation but reasonable).
You only have aerodynamic capability to pull about 3.5 G.

But, you've got the same KTAS. The point is that True Air Speed
doesn't consistently offer aerodynamic performance. It's those little
molecules doing their Bernoulli thing over the wing surface that makes
it happen--KIAS!


Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
"Phantom Flights, Bangkok Nights"
Both from Smithsonian Books
***www.thunderchief.org

On Sun, 15 Aug 2004 06:54:50 -0500, "John Carrier"
wrote:

BTW, John, I've read that the (hard-wing) F-4 could generally
beat
the F-8 at low/medium altitude (once the pilots learned to use its energy
advantage), but at high altitudes the F-8's lower drag (induced, parasitic
and/or wave) gave it the advantage. What's your take?

Pretty good numbers, I think.

As to the F-8 versus F-4, you presented the prevailing conventional wisdom
of the time. When I was an F-8 guy, I felt I pretty much could have the
Phantom for lunch. But there was a time or two when the individual I
opposed transformed the jet into a serious adversary, "Who IS that guy?"

The F-8 had superior PsubS under G than the Phantom at altitudes above
15,000 feet, so any kind of classic turning fight (oblique loop, etc was the
thing in the tacmans at the time) played to its advantage. The Phantom was
more controllable very slow and enjoyed superior unloaded acceleration.
That points to a VERY vertical fight.

When I finally transitioned to the F-4, I thought, "No wonder it was so easy
to beat up on this jet." But, by the 500 hour mark I had changed to, "How'd
we EVER beat up on this jet?" The F-4 was the antithesis of the
point-and-pull fighter and required a great deal of finesse to fight well
(skills that many never achieved IMO). Once mastered, you could
successfully engage just about any aircraft of its generation ... albeit a
roller with a Mig-17 was ill-advised (hear that, Duke?). Of course, once
the next generation appeared (F-14 and subsequent), there really wasn't
anyplace to take the fight they couldn't go.

R / John


I concur. One major factor was that the F-8 community was much like
the USAF's 479th TFW/435th TFS F-104 bunch--a group optimized for day
fighter air-superiority ops. They were the lead element of the
creation of new tactics--things like Fluid Attack and Loose Deuce
along with detailed analysis of what was really going on in vertical
maneuver, split-plane operation, and one-circle/two-circle fights. (I
freely admit that the USN was well ahead of the USAF at that point in
air/air development).

And, you highlight the demand of that era to take the fight to your
best corner of the envelope. Plus, you correctly note that the advent
of the "teen fighters" means that every corner of the modern envelope
is now available and the fight goes to the better weapon and better
trained aviator.


Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
"Phantom Flights, Bangkok Nights"
Both from Smithsonian Books
***www.thunderchief.org

Andy Bush wrote:

My F-5E chart for 5000'MSL (50% fuel, 2 AIM-9) gives a 7g corner at about
365KCAS and a sustained 7g capability at about 600KCAS for a rate of just
under 12dps. That's really honkin' for this jet...a more realistic sustained
value is about 9.5dps at 430KCAS...the curve wanders a bit, but that works
out as around 4.5g or so.

My thanks to you and John for the info.

Guy

Ed Rasimus wrote:

On Sat, 14 Aug 2004 23:45:17 GMT, Guy Alcala
wrote:

John Carrier wrote:

Generally, the sustained turn rate was around 14-15 degrees/second for
the F-4 hard-wing and about 12.5-13.5 for the F-105.

H'mm, those numbers seem kind of high for both, as far as sustained
capability
goes.

400 KTAS, turn rate in Deg./sec. (rounded off) = 19 (7g); 22 (8g).

500KTAS, turn rate in Deg./sec. (rounded off) = 15 (7g); 17 (8g); 20 (9g).

600KTAS, turn rate in Deg./sec. (rounded off) = 13(7g); 14 (8g); 16 (9g).

I'm missing something here. You say the numbers are high and then offer
higher numbers. Or are these just basic computations of turn rates w/o
regard to airframe factors?

snip

Yes. I wanted to show what the maximum turn rate was for the various KTAS/g
combinations; sustained would be less.

Guy

I woke in the middle of the night thinking about this discussion--I
know, it indicates some level of neuroses....

I've said that KIAS not True Air Speed is the relevant number, you
indicate a desire to relate G available and hence turning performance
to KTAS.

Consider this. At low altitude, true air speed can be quite close to
indicated. It will always be higher than indicated, but not
exceptionally higher. So, if you are running around at corner velocity
(always expressed in KIAS) of say 420 KIAS, you might be at 475 KTAS
and you could pull max allowable G.

Now, move the airplane up to FL450 and establish the same 475 KTAS
condition. Ooopps! You're cruising around at something less than 300
KIAS (don't dissect the number, it's an approximation but reasonable).
You only have aerodynamic capability to pull about 3.5 G.

But, you've got the same KTAS. The point is that True Air Speed
doesn't consistently offer aerodynamic performance. It's those little
molecules doing their Bernoulli thing over the wing surface that makes
it happen--KIAS!

Ed, I know. But the question was about max. degrees per second (instantaneous or
sustained) capability, and that is a function of TAS and g, irrespective of
altitude. If you look at KIAS/KCAS and g, you can say that the a/c reaches corner
at say 420KCAS, but does that tell you how many degrees per second you're turning?
No, because you have to take account of the altitude and then translate IAS/CAS
into TAS, and then use g to have any idea of what the radius/rate is. It's
certainly possible to calculate radius/rate using IAS/CAS and g, but far more
tedious than just using TAS, which applies at any altitude without conversion.
Other than that, I think we all know that best turn rate/radius happens in the
densest air, with the rate decreasing and the radius increasing with altitude,
given constant IAS/CAS.

In short, we're in complete agreement about the effects, just using the numbers for
different purposes. You are approaching the problem from the pilot's perspective
using KIAS/KCAS, a relative value; you don't really care what the actual number is
or what the measurement system is (radians per hour, anyone?), just that it will
give you the quickest, tightest turn or a Zero Ps turn (and in combat, knowing that
you will be advantaged/disadvantaged against a particular opponent). I'm
approaching it from the perspective of an absolute value, which is necessary to
answer the OP's question about deg./sec.

Guy

On Sun, 15 Aug 2004 17:45:57 GMT, Guy Alcala
wrote:



You are approaching the problem from the pilot's perspective
using KIAS/KCAS, a relative value; you don't really care what the actual number is
or what the measurement system is (radians per hour, anyone?),

I've always tried to do my X-country flight planning using furlongs
per fortnight. Tough to find the conversion factor on my E-6B though.



Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
"Phantom Flights, Bangkok Nights"
Both from Smithsonian Books
***www.thunderchief.org

Ed Rasimus wrote:

On Sun, 15 Aug 2004 17:45:57 GMT, Guy Alcala
wrote:


You are approaching the problem from the pilot's perspective
using KIAS/KCAS, a relative value; you don't really care what the actual number is
or what the measurement system is (radians per hour, anyone?),

I've always tried to do my X-country flight planning using furlongs
per fortnight. Tough to find the conversion factor on my E-6B though.

That's just one of the many advantages of electronic flight computers, but those
spoilsports at the FAA refuse to play along. Personally, I think rather than using Mach
we should begin the changeover to using fractions of 'c' (SI or English makes no never
mind, except for the engineers). We'll need to eventually, and (judging by the rate at
which the US has accepted converting to metric) we should have nearly accepted the new
units around the time we're likely to need them;-)

Guy

And the Bulgarian Judge awards Guy Alcala a 2.1 for artistic ability
and a 10.0 for technical difficulty for introducing General Relativity

Personally, I think rather than using Mach
we should begin the changeover to using fractions of 'c' (SI or English makes no never
mind, except for the engineers).

The Bulgarian Judge deducted points for not specifying MPS or
KPS...nice try anyway.

Robey