Foxbat and F-15
dennis...@dwt.csiro.au
Foxbat and the MiG-25. I will add my own disclaimers.
From: mbov...@orlando.loral.com (Mark Bovankovich)
> I was intrigued by the "MiG-25 Performance" subject in your Russian
>aviation page FAQ list. I am somewhat knowledgeable about the MiG-25, and would
> like to address Joe Barrington's and Thomas Rodriquez's comments.
>Hopefully you and your readers will find this analysis interesting.
>In his response to Joe Barrington's MiG-25 post, Thomas Rodriguez made the
>important point that we should not denegrate Soviet designers as inept, lacking
>in
>ingenuity or concern for pilots' safety. Unfortunately, the rest of the points
>Thomas made were less than valid. Let me explain.
>MiG-25 Engines -
> Engine control at high Mach is extremely difficult in a design like the
>MiG-25, let alone a system like the A-12/YF-12/SR-71. The problem is that the
>engine
>begins to act like a ramjet at speeds in excess of Mach 2.5 or so, and the
>turbine's speed is increasingly dictated by the flow through the propulsion
>duct rather than
>by fuel control. In the case of the Blackbird (or Cygnus), the J58 engine
>bypasses air past the rear stages of the compressor straight into the
>afterburner duct. This
>bypass, along with the complex inlet and nacelle bypass door contol system,
>works to stabilize the flow through the engine. The R-15 lacks the J58's
>compressor
>bypass, and the MiG-25 has only a single inlet duct bypass system. So--without
>going into gory engineering details--the results are engine speed control
>problems at
>high Mach. Engineering analysis aside, you might want to consider the following
>facts:
First, this is blatant nonsense. All turbojets and turbofans that I am aware
of operate with subsonic airflow. So where is the magic with M2.5? Unless the
inlet design does not reduce the airflow to the subsonic regime, there will
be no problem with this "ram effect". Indeed, the massflow at >60K at M3 will
be significantly less than for a subsonic Foxbat at SL, and given that the
airflow through the engine is subsonic, this is blatant nonsense.
> The MiG-25 that was clocked at Mach 3.2 by the Israelis achieved this
>speed while running from an intercepting F-4 (which can barely manage Mach 2 on
>a
> good day--before running out of fuel). Upon landing, both engines in the
>MiG had to be replaced.
> Victor Belenko, the Foxbat pilot who defected in 1976, stated that the top
>speed of the MiG-25 was Mach 2.8, but flight above Mach 2.6 was difficult
> because of a tendency of the engines to overspeed. Victor related that
>MiG-25 pilots were in fact restricted to flying below Mach 2.5 except with
>special
> permission.
>Joe's story fits in well with the facts.
>Foxbat g-Limits -
> Thomas' analysis of the Foxbat's load limits is intersting, but hardly
>accurate. The Foxbat is only cleared for 4.5g supersonic maneuvers when its
>fuel is almost
>depleted. When the internal tanks are more than half full, the load limit is
>3g. You might note, Thomas, that the Foxbat did not have to conform to the
>"tough safety
>regulations" (implying high design safety factors) because of the performance
>levels that needed to be attained. You'll note that Foxbats can't operate off
>dirt strips
>like other MiGs, either.
>This said, your assessment that the MiG-25 has no real requirement to pull high
>g's at supersonic speeds is probably correct. In a high Mach intercept mission,
>the
>MiG-25 should be using its excess thrust for climb, not for turning. The GCI
>should ensure that the Foxbat is positioned so that it can complete the
>intercept without
>violent maneuvers.
>You might note that the A-12/YF-12/SR-71 is limited to 45 degrees bank at
>design speed and altitude. It is also limited to 1.5g under these conditions.
>Furthermore, the Blackbird is only cleared up to 400 KEAS at high Mach, a far
>cry from the (often ignored and exceeded) Foxbat's 650 KEAS limit.
Except that 400KEAS at cruising altitude is far more than the Foxbat is
capable of.
>Compared
>with the SR-71, the MiG-25 is quite agile at speed.
>MiG-25 Speed Limit -
> Thomas said that the Foxbat can carry its full weapons load to Mach 2.8,
>while a clean recon version can do Mach 3+. Actually, the recon versions have
>the
>same limit as the interceptors: Mach 2.83. This is not a thrust limit. You
>might note that the RB versions of the Foxbat can carry four bombs(!) to Mach
>2.83. The
>Mach 2.83 is a theoretical stability limit on the airframe (which has been
>safely exceeded on numerous occasions by test pilots). At speeds greater than
>Mach 2.6
>however, throttle control must be precise to keep the engines from
>overspeeding.
>Western Fighter Comparisons -
> Lest you think that I am implying that the Foxbat is not a capable
>aircraft, especially in performance, you might consider the abilities of
>Western fighters. The
>F-16 can just barely squeak past Mach 2.0 with a pair of tip 'winders. The F-14
>can only manage Mach 1.81.
I would like to know where this "fact" comes from. I have only seen M2.34
quoted.
>And the mighty Eagle is only good for Mach 1.78.
Once again, the Eagle achieved 2.54 in flight tests, and the Dash-1 also says
M2.5.
>The Foxbat can outclimb all of these fighters by a healthy margin, and has a
>mauch better supersonic endurance than the best Western fighter.
I don't know about supersonic endurance (SFC in burner figures lead
me to doubt Bogvankovich here), but as far as climb is concerned,
the F-15 and F-16 will comfortably out climb the -25 (just have a
look at T:W ratios).
>Furthermore, the
>Foxbat has demonstrated the ability to outrun all U.S. frontline fighters at
>_low_ altitude. The Foxbat is hardly a dud.
I really would like to see a reference for this one. Data that I have seen
indicates that the -25 is subsonic at SL, and the -31 only just supersonic.
OTOH, the Tornado, F-15, F-16 and F-111 (okay the latter is hardly a fighter)
can all run at M1.2 at SL, far better than I have ever seen alluded to (apart
from this article).
>Gulf War Experience -
> Did you know that a MiG-25PD recorded the only Iraqi air-to-air kill of
>the Gulf War? It dropped an F-18C on the first night of the war--then went on
>to
>fire another missile at an A-6 and buzz an A-7, all while avoiding escorting
>F-14s and F-15s.
there has been considerable argument about this kill. It is still not know
what happened to the -18, it could have been CFIT.
>An isolated incident? How about the single Iraqi Foxbat-E that eluded eight
>sweeping F-15s then tangled with two EF-111As, firing three missiles at the
>Ravens
>and chasing them off station. Unfortunately, the Ravens were supporting an
>F-15E strike, and the EF-111's retreat led to the loss of one of the Strike
>Eagles to a
>SAM. Oh BTW, the Foxbat easily avoided interception and returned safely to
>base.
>There's more. When F-15 pilots were fighting for the chance to fly sweeps east
>of Baghdad late in the war, itching for a chance to get a shot at an Iraqi
>running for
>Iran, they weren't expecting the fight that a pair of Foxbats put up. Two
>Foxbats approached a pair of F-15s, fired missiles before the Eagles could get
>off shots
>(the missiles were evaded by the Eagles), then outran those two Eagles, four
>Sparrows and two Sidewinders fired back at them. Two more Eagles maneuvered to
>cut the Foxbat's off from their base (four more Eagles tried, but were unable
>to effect an intercept), and four more Sparrows were expended in vain trying to
>drop
>the Foxbats.
>The Iraqis had a total of twelve MiG-25PDs at the beginning of the war, of
>which maybe half were operational at any given time. Imagine what trouble they
>would
>have caused if there had been more. The Foxbats, when well flown, proved
>capable of engaging allied fighters and avoiding them at will. Only the
>limitations of their
>weapons proved a problem.
This is absolutely nonsense. When Israel got F-15s, -25 overflights of Israel
stopped immediately. Same with Iran and F-14's. Reading Bovankovich, you
would think that the MiG-25 was still a wonder weapon. Have a look at the
kill ratios of the F-15 and the MiG-25-that clearly puts this argument to
bed. No F-15's have ever been lost in A-A combat, and they have nearly 100
kills. Can the same be said of the -25:)
>Foxbat's Effect on Eagle Design-
> Dispite the attempts of Riccioni, Spey and Boyd, the F-15 Eagle turned out
>to be quite a disappointment. Designed as a replacement for the F-4 with a
>multi-role capability (I bet you thought it was designed strictly for air
>superiority; wrong!),
This is absolutely crap. I have communicated with people who worked in the
F-15 design office, and they confirm that it was designed purely for air
superiority, and that the adage "not a pound for air to ground" was indeed in
the design office in foot high letters at the time. I also supposed the
Flight, Air International and AW&ST were all incorrect at the time, as was
IDR.
>the design modifications brought on by misconceptions >about the Foxbat
>made the Eagle an expensive, less-than-capable aircraft. (A mistake, IMHO) The
>Eagle ended up with a range significantly inferior to the F-16. It is slower at
>high
>and low altitudes than the Falcon.
Where does he come about this crap. It is faster at high altitudes, and has
about the same speed at low altitudes as the Falcon. It also has
significantly better range-where the crap about the F-15 having a short range
comes from, I do not know!
> Its huge radar, thermal and visual signatures negate many of the advantages of
>its (somewhat unreliable) radar.
I would agree that the observables are horrible with the F-15. But the radar
is excellent and, in recent years, very reliable (recent being the last 15-20
years).
>It has proven
>expensive to procure, maintain, and support.
Nonsense. A new F-15 can be procured for about the same as a new F-18.
>We had a counter for the Foxbat: the F-12B. The Eagle should have remained a
>multi-role aircraft. The Strike Eagle has proven the airframe's abilities in
>this role.
Yes it has, despite not originally having been designed for multirole.
Dennis
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Yama
>
> From: mbov...@orlando.loral.com (Mark Bovankovich)
>
> >Western Fighter Comparisons -
>
> > Lest you think that I am implying that the Foxbat is not a capable
> >aircraft, especially in performance, you might consider the abilities of
> >Western fighters. The
> >F-16 can just barely squeak past Mach 2.0 with a pair of tip 'winders. The F-14
> >can only manage Mach 1.81.
>
> I would like to know where this "fact" comes from. I have only seen M2.34
> quoted.
>
> >And the mighty Eagle is only good for Mach 1.78.
>
> Once again, the Eagle achieved 2.54 in flight tests, and the Dash-1 also says
> M2.5.
He obviously referred to practical speed limits. Eagle can't carry
any weapon loads if it wants to reach Mach 2.5 - not even cannon
rounds in the magazine IIRC. Foxbat (and -hound) can carry missiles
up to 2.5. Pretty much all other fighters are limited to ~1.8 with
any weapon load. Also I've heard a rumour that new canopy material
for Eagle scratched of 0.7 Mach from the top speed. Dunno if this is
true though.
>
> >Furthermore, the
> >Foxbat has demonstrated the ability to outrun all U.S. frontline fighters at
> >_low_ altitude. The Foxbat is hardly a dud.
>
> I really would like to see a reference for this one. Data that I have seen
> indicates that the -25 is subsonic at SL, and the -31 only just supersonic.
Dunno about -25, but figures I've seen about SL top speed for -31
have been about 1500km/h. As much or more than Tornado.
> >It has proven
> >expensive to procure, maintain, and support.
>
> Nonsense. A new F-15 can be procured for about the same as a new F-18.
Not true, unless you mean Hornet E/F.
Anthony de Vries
dennis...@dwt.csiro.au wrote:
> >MiG-25 Engines -
>
> > Engine control at high Mach is extremely difficult in a design like the
> >MiG-25, let alone a system like the A-12/YF-12/SR-71. The problem is that the
> >engine
> >begins to act like a ramjet at speeds in excess of Mach 2.5 or so, and the
> >turbine's speed is increasingly dictated by the flow through the propulsion
> >duct rather than
> >by fuel control. In the case of the Blackbird (or Cygnus), the J58 engine
> >bypasses air past the rear stages of the compressor straight into the
> >afterburner duct. This
> >bypass, along with the complex inlet and nacelle bypass door contol system,
> >works to stabilize the flow through the engine. The R-15 lacks the J58's
> >compressor
> >bypass, and the MiG-25 has only a single inlet duct bypass system. So--without
> >going into gory engineering details--the results are engine speed control
> >problems at
> >high Mach. Engineering analysis aside, you might want to consider the following
> >facts:
>
> First, this is blatant nonsense. All turbojets and turbofans that I am aware
> of operate with subsonic airflow.
Correct.
> So where is the magic with M2.5? Unless the
> inlet design does not reduce the airflow to the subsonic regime, there will
> be no problem with this "ram effect".
Just to add a little. A ram jet also doesn't have an internal
supersonic airflow. It's basicly just an normal jetengine, but without
the moving parts. So, without the fan. The inlet, where the flow
becomes subsonic, and outlet where it becomes supersonic again, are
still the same. Because a ramjet has no moving parts, it's the more
efficient than the normal jetengine at high speeds. Ofcourse it's a bit
of a nuisance that it can't take-off normally, because it needs a
highspeed airflow before it can ignite.
A supersonic ram-jet is often called a scram-jet. Combustion at
supersonic speeds is a big problem here. As far as I know there are no
aircraft operational with such an engine.
> >We had a counter for the Foxbat: the F-12B. The Eagle should have remained a
> >multi-role aircraft. The Strike Eagle has proven the airframe's abilities in
> >this role.
>
> Yes it has, despite not originally having been designed for multirole.
Also hardly surprising. A 100% air-superiority fighter needs a big
wing, to get a low wingload. Ofcourse, that also means that you can hang
a lot of bombs under it.
Compare the Strike-Eagle to the Tornado or F-111, and you immediately
see that the Tornado's and F-111's airframe is much better suited for
the bomber role. At low level, those two ride much smoother, and are
much faster.
The strike-eagle is a usefull bomber because of the advanced avionics.
Not because the airframe is so good for it.
Anthony.
John Carrier
and did a little reading beyond Belenko's book.
>>You might note that the RB versions of the Foxbat can carry four bombs(!)
to Mach
>>2.83.
Not likely.
>>The Mach 2.83 is a theoretical stability limit on the airframe (which has
been
>>safely exceeded on numerous occasions by test pilots).
Structural. The airframe has to be parked after a few minutes above the
limit because of aero heating damage. Alleged 3.2 flight (I've had radars
tracking me in a TA-4 at 1.05 when I was cruising at 41K and .74 IMN) is
hardly definitive.
>>Western Fighter Comparisons -
>> Lest you think that I am implying that the Foxbat is not a capable
>>aircraft, especially in performance, you might consider the abilities of
>>Western fighters. The F-16 can just barely squeak past Mach 2.0 with a
pair of tip >>'winders.
On a very good day, maybe.
>>The F-14 can only manage Mach 1.81.
I routinely ran the Turkey to 1.88 (an artificial NATOPS limit,
manufacturer's limit was 2.34) on test hops. It would still accelerate
nicely there.
>>Furthermore, the Foxbat has demonstrated the ability to outrun all U.S.
frontline fighters at _low_ altitude. The Foxbat is hardly a dud.
Foxbat Q limit is 540 KIAS. On the deck it's a stone.
Foxbat was designed as an interceptor for the B-70 threat. Proved to be a
decent recce platform (but I'm not sure the sensor suite matched the aero
performance). As an air superiority machine, it was out of its element.
Poor fuel specs outside it's supersonic cruise environment, low Q limit, low
G limit, poor turn performance (even if it had a decent G limit), weapons
system optimized for high altitude intercept (with admittedly pretty good
head on performance), not a maneuvering engagement.
As to the F-18 kill ... even a blind squirrel gets the acorn once in a
while.
R/ John
Steve Richardson
> >to be quite a disappointment. Designed as a replacement for the F-4 with a
> >multi-role capability (I bet you thought it was designed strictly for air
> >superiority; wrong!),
>
> This is absolutely crap. I have communicated with people who worked in the
> F-15 design office, and they confirm that it was designed purely for air
> superiority, and that the adage "not a pound for air to ground" was indeed in
> the design office in foot high letters at the time.
At last, something I know about! Having worked at McDonnell Douglas for
umpteen years, now Boeing in St Louis, I can tell you it's a 100% fact
that the F-15 was designed under the banner (literally) "Not a Pound for
Air to Ground." There was a darned good reason, too. The entire
defense community was panicked over the MiG-25 because the ubiquitous
F-4 couldn't match it in either performance or in weapon system
capability, ON PAPER. I emphasize that last bit because as it turned
out, quite a bit of the data available at the time turned out to be
pretty badly wrong. At any rate, the MiG-25 looked to be a quantum leap
forward and the US needed something to match it. When you set out to
counter an enemy air threat, you end up focusing on air-to-air metrics.
Multirole becomes a luxury (remember this was the late 1960s/early
1970s, before we all started worshiping the affordability gods and could
still build dedicated-role aircraft). If you put in supporting
structures for multiple bomb racks, then weight goes up, acceleration
goes down, turn rate goes down, etc etc etc. Not good for your design
mission of "air superiority" and remember we were trying to close a
massive performance gap in the first place. Any bomb-dropping that
needed to be done could be done by F-4s, but the F-15 had to keep them
safe from enemy counterair threats. So it became our designated "air
superiority fighter", not "fighter-bomber" or "strike fighter" or
whatever.
Anybody know Viktor Belenko, the guy who defected with a MiG-25 in
1976? Maybe we could ask him which aircraft he'd rather fly!
- Steve Richardson
Mike Kelly
On Fri, 5 Mar 1999 dennis...@dwt.csiro.au wrote:
[snip]
>
> >And the mighty Eagle is only good for Mach 1.78.
>
> Once again, the Eagle achieved 2.54 in flight tests, and the Dash-1 also says
> M2.5.
>
Dennis,
Yes, one of the prototypes or FSD aircraft did achieve 2.54, but
that airplane had a nickname, Patches. The reason every time it flew
above mach 2 hair line cracks formed in the ducts that had to be repared.
They increased the skin thickness three times and still had the same
problem. BTW that story was related to me by the former director of the
F-15 test force from 75-76. Any how, with a full weapons load I think 1.8
is as fast as the bird will do.
Michael Kelly
[more snips]
Jussi Saari
>
> >>You might note that the RB versions of the Foxbat can
> >>carry four bombs(!) to Mach 2.83.
>
Probably not quite Mach 2.83, but they certainly flew way past Mach 2
with bombs, at least up to Mach 2.3 - 2.4 according to World Airpower
Journal. Specifically modified heat-resistant bombs, pylons and ejection
racks had to be designed for MiG-25RBs because of the very high speed.
(Apparently development of those didn't proceed entirely smoothly, and
there was some trouble with parts melting and pyrotechnical charges for
releasing the bombs were going off spontaneously from the heat...)
> >>Mach 2.83 is a theoretical stability limit on the airframe
>
> Structural. The airframe has to be parked after a few
> minutes above the limit because of aero heating damage.
True, just 5 minutes between Mach 2.65 - 2.83 was the limit. OTOH, it
seems that the Indian Air Force hasn't followe those limits all that
carefully, and their Foxbats are still flying...
> >>The F-14 can only manage Mach 1.81.
>
> I routinely ran the Turkey to 1.88 (an artificial NATOPS limit,
> manufacturer's limit was 2.34) on test hops. It would still
> accelerate nicely there.
But that would be without external ordnance, right?
> weapons system optimized for high altitude intercept
> (with admittedly pretty good head on performance)
Do you know how they handled the fusing, was the proximity fuse fast
enough for SR-71/B-70s, or was the goal to get a direct hit ?
Jussi
bor...@pacbell.net
>
> >The Foxbat can outclimb all of these fighters by a healthy margin, and has a
> >mauch better supersonic endurance than the best Western fighter.
>
> I don't know about supersonic endurance (SFC in burner figures lead
> me to doubt Bogvankovich here), but as far as climb is concerned,
> the F-15 and F-16 will comfortably out climb the -25 (just have a
> look at T:W ratios).
>
Thrust to weight ratio is just as important a factor when performing a
"time-to-climb," as is the flight profile flown to reach the desired altitude.
Kevin
Carlo Kopp
> >
> > Once again, the Eagle achieved 2.54 in flight tests, and the Dash-1 also says
> > M2.5.
> >
>
>
> Yes, one of the prototypes or FSD aircraft did achieve 2.54, but
> that airplane had a nickname, Patches. The reason every time it flew
> above mach 2 hair line cracks formed in the ducts that had to be repared.
> They increased the skin thickness three times and still had the same
> problem. BTW that story was related to me by the former director of the
> F-15 test force from 75-76. Any how, with a full weapons load I think 1.8
> is as fast as the bird will do.
>
> Michael Kelly
>
> [more snips]
> >
>
What is performance like with a clean wing, and only four AIM-7 or 120
on the fuselage stations ?
Thanks,
Carlo
P38Eddie
would.
Agtabby
speed does not seem to be the priority.
My question is: wouldn't a mach 2.5 fighter be useful to attack and run "one
pass and then haul ass"? Isn't this how an F18 was shot down in the Guld War
by a M25?
Andrew
Kurt Plummer
Yes, if you can use it offensively. The main problem with the Iraqi fighter
defense in the first night of DS was their belief that we could crush them in a
blow and that they would be better off weathering 'The Storm' with the potential
of later contribution. This was pure idiocy because they /never had/ a chance to
survive as long as they hid on airfields under-HAS but they darn well could have
embarrassed U.S. rather more initially before/as they exited the stage.
IMO, even the AA-6 has enough LDSD to put the tanker orbits in serious trouble and
if you could have found stretches of road long enough and FEBA close enough or
mixed-force (MiG-29's have those ducts...) 'cluttered' enough to press the
controllers and split the altitude bands of the Eagles, you've got a prayer of
pushing over/under-THROUGH the leadsweeps.
Of course coordination is essential but a Foxbat can ramp at a pretty clip from a
fairly distant GLI and still be an effective threat inside 5 minutes. We only had
about 60 F-15C's over the theatre that night (and admittedly a passle of 14/18
with equivalent Sparrow capability) but unless he /insists/ on running right down
your throat; you're not likely going to get a clean kill on Mr. MiG with Sparrow.
F-15's are good mid-Mach interceptors but getting a cutoff on a platform 20K above
you and crossing fast will eventually pose as much a missile/fuzing problem as
anything.
Add the least little bit of 'processing clutter' from a low-runner split and all
the tankers which we had pushed right up to the border could have been Very
Vulnerable.
The Sapfir-25 is about 2/3rds as powerful as the Smerch-A and that's still a -lot-
of ERP. If you add in the IRST (I /think/ the Iraqi PDS have them) and the LOAL
capability of the R-40TD and you've got a helluva reach, even in a heavily jammed
environs.
Today, the 25's still have potential but it is likely more in the bombing role
with inertially corrected or TerHom seekered weapons. A FAB-500M--62T will
/ballistic glide/ over forty miles from a 21,000m and 2,500kmh 'dropkick' (I'm
going from the 'corrected' distances of 406'miles' and 350 'miles' listed in
_MiG-25 Foxbat/MiG-31 Foxhound_ by Yefim Gordon).
Add a good offset aimpoint maneuver kit (high altitude thrusters to set oblique
approach angles as well as larger, insulated, tail fins) via the later Sablya or a
WAGE equivalent aiming and you'd have one viciously effective 'frontal bomber'.
Keeping in mind the basic shortcomings of radii and the inability to carry bombs
when the centerline tank is carried.
As an interceptor, the system is likely crippled by it's two-spar wing and low Q
but /could/ manage better with a newer radar/missile combinant. Trials with the
NO-93 and AA-10 were scheduled but apparently the weapons inability to super-soak
for extended periods (and the rise of the MiG-31 project) made it impractical to
refit the system. Similar efforts with R15BF2-300 and what would become the
MiG-31 D-30 engines yielded range improvements on the order of 200% and sustained
Mach/Altitude combinants in the region 3,500kmh and 25-35K meters.
'Unfortunately', the first efforts were invalidated by the depth of redesign
inherent to the /airframe/ structure to absorb the heating effects and the second
was basically a one-off for the Foxhound with a nearly-all-new backend and
compression ramp system.
One last thing. According to the Soviets, (those poor belittled innocents) it
was purely an error of navigational computation (excess Med salinity) by the
ground team which pushed them over the Israeli border and typical mission orders
forbade them from coming within 10-20km of it (i.e. start the turn 100-120km away
from minimums).
On the two occasions when the MiG's were pressed past 3,000km/h the airframes were
not apparently damaged under inspection (the entire high speed run from Suez to
Port Said only took a couple minutes) but the pilots received stern debriefs.
Typical cruise profiles called for MUCH lower 'combat Mach' of 2.3/2.4. It was
the border-cross and a British naval surveillance hit from off /Crete/ which
account for the 'Exceeded Mach 3.2' baloney.
I think it's height which messes things up for the missile slants 'faster' than
raw momentum and here too, the Soviets did a very careful 'grand tour'
sensor/waypoint calibration run over the Valley of Kings monuments as they
literally 'burnt off to burner up' to cruise values ranging from 52-75K feet as
they approached ever closer to the sensitive border areas.
The book mentions that the Israeli's tried awfully hard to catch the 'Bats on the
snapup and the downslides with airfield attacks as well as intercept and due to
this and large leaks within the Egyptian military security the Russians had to
play pretty cagey with ATC takeoffs vs. overhead cover and approach bearings and
TAC descent profiles (the 25 was over 1:1 at the mission end so this helped a bit
but the Q problem is still there...) on getting the beastie safely back in the
barn. Eventually they put up two heavy HAS complexes with direct-let onto the
actives -just- for the MiG-25.
KP
Dweezil Dwarftosser
<ch1...@earthlink.net> wrote:
>Of course coordination is essential but a Foxbat can ramp at a pretty clip from a
>fairly distant GLI and still be an effective threat inside 5 minutes. We only had
>about 60 F-15C's over the theatre that night (and admittedly a passle of 14/18
>with equivalent Sparrow capability) but unless he /insists/ on running right down
>your throat; you're not likely going to get a clean kill on Mr. MiG with Sparrow.
>F-15's are good mid-Mach interceptors but getting a cutoff on a platform 20K above
>you and crossing fast will eventually pose as much a missile/fuzing problem as
>anything.
Kurt -
Your sources for the above description of AIM-7 and other US radar
missiles is woefully in error. While a head-on shot presents the
missile with increased firing range, fuzing might be a problem with
a mach 3 closing rate between target/inteceptor. Direct hits are
not unknown in this regime, just uncommon.
However, the "crossing" shot at right angles to the inteceptor's
flight path is precisely what these missiles/systems were designed for
- especially so, when the target is at a higher altitude band.
This is the classic lead-pursuit "ideal" engagement for these weapons.
- John T.
ftrplt
>
>Your sources for the above description of AIM-7 and other US radar
>missiles is woefully in error. While a head-on shot presents the
>missile with increased firing range, fuzing might be a problem with
>a mach 3 closing rate between target/inteceptor. Direct hits are
>not unknown in this regime, just uncommon.
>
>However, the "crossing" shot at right angles to the inteceptor's
>flight path is precisely what these missiles/systems were designed for
>- especially so, when the target is at a higher altitude band.
>This is the classic lead-pursuit "ideal" engagement for these weapons.
>
>- John T.
>
what a load of absolute rubbish!!!!
The 'crossing shot' at right angles is the worst case scenarion for a semi
active missile; not even considering the High Fast flier implications.
(which are bad unless absolutely head on)
Kurt Plummer
> On Tue, 09 Mar 1999 07:01:40 -0700, Kurt Plummer
> <ch1...@earthlink.net> wrote:
>
> >Of course coordination is essential but a Foxbat can ramp at a pretty clip from a
> >fairly distant GLI and still be an effective threat inside 5 minutes. We only had
> >about 60 F-15C's over the theatre that night (and admittedly a passle of 14/18
> >with equivalent Sparrow capability) but unless he /insists/ on running right down
> >your throat; you're not likely going to get a clean kill on Mr. MiG with Sparrow.
> >F-15's are good mid-Mach interceptors but getting a cutoff on a platform 20K above
> >you and crossing fast will eventually pose as much a missile/fuzing problem as
> >anything.
>
> Kurt -
>
> Your sources for the above description of AIM-7 and other US radar
> missiles is woefully in error. While a head-on shot presents the
> missile with increased firing range, fuzing might be a problem with
> a mach 3 closing rate between target/inteceptor. Direct hits are
> not unknown in this regime, just uncommon.
>
> However, the "crossing" shot at right angles to the inteceptor's
> flight path is precisely what these missiles/systems were designed for
> - especially so, when the target is at a higher altitude band.
> This is the classic lead-pursuit "ideal" engagement for these weapons.
>
> - John T.
>
Well Hell Dweezil,
I'm prepared to be wrong just about any ol' time and I even have a pic to support your
claim from _Modern Military Aircraft: F-15_. Michael Gething's book has a shot on
pg.109 with the backseater looking over the pilot's shoulder as the weapon snaps up on
a 30-40` plane against a 'crossing' target that looks like it's about 110-120 and
laying a con vs. the F-15 jock who is perhaps 5-10K above some snowy elevated terrain
(Alaska?).
But it remains to be said the only time I know of an Eagle taking an effective
high-fast Foxbat Sparrow shot was when an Israeli HAWK helped him out, turning the
MiG-25 into the Eagles firing lane and dropping a bunch of altitude to boot, IIRC.
Another book, _Modern Fighter Combat_, mentions a rough Mach 4= turning radius of about
14.5dps at the tropopause for a 30G capable missile (which I'm guessing is about right
for Sparrow-M) and it seems fair that half of that rate for another 30K of altitude is
'probable'.
Given the effects of decreasing drag and motor mass the turn may still be pretty good
but the Foxbat is doing close to a 1,000m/sec and can pull 3-4G I'm told.
My basis for the fuzing problems comes from one of those 'swirly pic' diagrams which
indeed puts the entire front 60-aft-to-150 zone into a blue 'look up preferable' area
but also includes a 20-59` 'fuzing problems possible' red swirl just in front of it.
I honestly didn't think a Sparrow had the lock-on OR legs to get into detonation
proximity before skipping out the backside of the fuze envelope.
I'm guessing that the system uses some kind of forward coned doppler radar trip with a
very narrow gate-shift and/or an impact delay check and/or possibly a backup SARH
sampler detonation channel 'switch' and at those particular angles (and those rates)
the system is in and out of the envelope too fast, seeing a 'blank' until it is past
the effective warhead mechanical radii (blast would attenuate pretty rapidly at 60-70K,
no?).
If you're using lo-hi interleave I wonder at the range accuracy and even if you /can/
use medium (power?) to keep the target from 'slipping out the sides' I'd guess that it
might not have the continuous angle rates off the main array, early enough, to command
Sparrow lead.
I guess you could put in a 'high fast' seeker program that biased a LOT of lead
(outside the main SARH return or seeker-sampling sidelobes and taking a track-breaker
chance?) to do a late-level 'collision check' with a false doppler fuzing input to the
sampler channel.
Essentially trying for an in-plane 'fly through' frag detonation, a second or so ahead
of the target. But what if junior MiGMeister roles the airframe 20` while the missile
is in 'pseudo-silent midcourse' and adds an X-y angular /and/ Z axis (range)
'undershoot' variable to the steering? Without losing a bit of height he's altered
(steepened and pushed out) the collision point yet more degree-seconds requiring a late
negative lead change yet further ahead of the SARH flood, hasn't he? And even in the
Foxbat cage-canopy I'd think you'd see the missile plume and be able to estimate lead
lines a LONG ways out in the FQ...
Anyway, I've always wondered how much of a PRF-switch lock and low-to-high Mach/Psec
power penalty we payed on our snapup 'ambush attack' profiles so...educate me??:) KP
Dweezil Dwarftosser
wrote:
>>Your sources for the above description of AIM-7 and other US radar
>>missiles is woefully in error. While a head-on shot presents the
>>missile with increased firing range, fuzing might be a problem with
>>a mach 3 closing rate between target/inteceptor. Direct hits are
>>not unknown in this regime, just uncommon.
>>
>>However, the "crossing" shot at right angles to the inteceptor's
>>flight path is precisely what these missiles/systems were designed for
>>- especially so, when the target is at a higher altitude band.
>>This is the classic lead-pursuit "ideal" engagement for these weapons.
>
>what a load of absolute rubbish!!!!
>
>The 'crossing shot' at right angles is the worst case scenarion for a semi
>active missile; not even considering the High Fast flier implications.
>(which are bad unless absolutely head on)
Assume for a second that you have an enemy aircraft crossing your path
at 10 miles:
Step 1. Lock the radar onto the target.
Step 2. Immediately follow the cues provided to you by the radar.
(This may include pouring on some throttle...)
Step 3. When cued, squeeze and hold the trigger.
Step 4. Continue to follow the cues and maintain lock after launch
until he becomes a flaming ball.
That's why your government spent millions per copy on those radar
sets. Follow the bouncing ball and the only way it can miss is
equipment malfunction. Try some of that "macho fighter jock" BS,
- using that missile as if it were a longer range gun - and you'll
probably miss.
- John T. ( the guy who peaked the radar on the only F-4E to ever
splash two supersonic firebees in one day, using inert AIM-7-E-2s.)
Dweezil Dwarftosser
I'm really sorry that I can't be more forthcoming about the AIM-7's
method of determining when it reaches the target - but it has a very
reliable method of doing so.
In a head-on shot, where the missile's velocity is added to that of
the launching aircraft ( always true ) PLUS the closing velocity of
the target, the timing between determining it is "time to explode"
and the actual "boom" may be enough to have the fragments slice
through the target's wash...behind the target. ( This assumes there
was no actual missile/target collision, of course.)
The whole point in a missile shot is that once the aircraft's target
intercept computer is "on the job", it _directs_ the attacker to
perform maneuvers which will increase the probability of a hit.
( i.e - moving to "center up" the target on the nose, changing the
min/max "hit" ranges dynamically to alert the crew to "close" on
the target if that is needed, and displaying a cue - used to be the
"aim dot" - which, if followed, will improve the chances.
In other words, taking a radar missile shot at a target crossing your
path actually becomes a tail chase by the time all of the interlocks
are satisfied. A really fast mover ( say...a Mig-25 at Mach 3, and
20,000 feet higher ), coupled with a relatively slow ( 500 knots )
attacker most likely will not result in the missile ever being
launched; max range on a quickly "opening" target can shrink to quite
a small value.
Ideally, the same scenario would run something like this:
- the target is noticed on the radar, crossing from the left.
- lockon is acquired, hopefully before passing the nose.
- the crew will be cued to immediately turn right, and induce a
"climb" component, as well.
- the Vc, which had been relatively small and fluctuating begins
to increase in the negative direction ( "opening rate" ) as the
target and attacker flight vectors come closer in angle-off.
With an opening Vc, the crew would normally pour on the heat so
they can catch up.
- by reducing the -Vc, ( hopefully, to a zero or positive value ) max
range on the missile envelope extends. With enough AB, the
attacker will reach a point where launch is possible, and a kill
is likely. THAT'S when the "shoot" lights start flashing - not
before.
That is how these things were designed to work. If the crew decides
to switch to "Interlocks out" and fire anyway, as he crosses the nose
- the chance of a kill is quite small.
BTW - in a scenario as described above, even a 10-g turn by the Mig
would only IMPROVE the chances of being hit - since he would slow down
( as perceived by the missile and attacker radar). His only hope
would be to keep straight away and as fast as possible; this will
reduce the max firing range of the missiles on board.
>
>But it remains to be said the only time I know of an Eagle taking an effective
>high-fast Foxbat Sparrow shot was when an Israeli HAWK helped him out, turning the
>MiG-25 into the Eagles firing lane and dropping a bunch of altitude to boot, IIRC.
Most likely, the "turn signal" reduced target -Vc enough to bring out
the Ra ( max range ) so that a shot was possible.
>I honestly didn't think a Sparrow had the lock-on OR legs to get into detonation
>proximity before skipping out the backside of the fuze envelope.
Since the -7E-2, the "fuzing envelope" has extended down to a very low
value - but the far end has always been max aerodynamic range.
>I'm guessing that the system uses some kind of forward coned doppler radar trip with a
>very narrow gate-shift and/or an impact delay check and/or possibly a backup SARH
>sampler detonation channel 'switch' and at those particular angles (and those rates)
>the system is in and out of the envelope too fast, seeing a 'blank' until it is past
>the effective warhead mechanical radii (blast would attenuate pretty rapidly at 60-70K,
>no?).
What can I say ? Your guess is wrong.
>
>If you're using lo-hi interleave I wonder at the range accuracy and even if you /can/
>use medium (power?) to keep the target from 'slipping out the sides' I'd guess that it
>might not have the continuous angle rates off the main array, early enough, to command
>Sparrow lead.
Ummm....let's just say that the sparrow's guidance/target
tracking/proximity-to-target detection is both much simpler than you
imagine, and more involved. ( "More involved", in this case, means
that it took a lot more info from the received RF characteristics -
and far less from any type of "programming" - even that inherent in
the hardware design.)
>Anyway, I've always wondered how much of a PRF-switch lock and low-to-high Mach/Psec
>power penalty we payed on our snapup 'ambush attack' profiles so...educate me??:) KP
Much of what you say here simply doesn't apply at all. ( Perhaps it
does with AIM-120s...)
If all of the AIM-7s ( including the boostered variety used as
shipboard SAMs ) eventually end up in a scrap heap, completely
replaced by something else which functions differently, I promise
a "fully descriptive" dissertation on the subject.
Till then, let's just say that a good AIM-7 kill was *so* dependent
on real-time fluctuating dynamic conditions that only an analog
computer could ( till very recently ) give a good "solve" to the
multiple dynamically-changing equations which made up the
instantaneous "envelope" grand equation. The AIM-7 was like that,
too. So simple it took a long time to come up with other,
math-intensive means to accomplish the same goal - and the missile
itself used no math at all internally !
Please permit me to give an analogy. Ever see some surveyors work to
determine the altitude of a nearby hillside using the known altitude
of a nearby location ? It involves measuring lengths/angles, some
trig, some expensive equipment, and calibrated plot-points.
Of course, a few hundred feet of transparent tubing full of liquid,
stretched between the hill and the known-altitude location can provide
the answer, readable with a tape measure. Just make sure both ends
of the tubing point upward - and fill it with fluid until the liquid
level matches the hillside.
Well...the AIM-7 is just like that. Simple and effective.
Launch it out of the envelope, and it's not effective at all.
- John T.
ftrplt
Dweezil Dwarftosser wrote in message
<36e72161...@news.rdu.bellsouth.net>...
ftrplt
on. If you dont position yourself based on AWAC / GCI calls you wont be
anywhere near a shot unless the BDT happens to be on the nose.
Fighter pilots know where to point the aircraft to achieve the best shots
without having to wait for the steering information from the aircraft.
Dweezil Dwarftosser wrote in message
<36e7256c...@news.rdu.bellsouth.net>...
Dweezil Dwarftosser
wrote:
>Which computer game did you learn how to employ BVR missiles on??
AN/APQ-120. Sixteen years' worth. And you ?
- John T., former MSgt, USAF, and member of the 1st, 4th, 15th,
36th, 50th, 56th, 86th, and 388th ( Korat Dive Toss )
Tactical Fighter Wings
http://www.geocities.com/pentagon/3227
D. Scott Ferrin
wrote:
Were you ever with the 388th at Hill?
Dweezil Dwarftosser
Ferrin) wrote:
>Were you ever with the 388th at Hill?
'Fraid not. Just at Korat.
- John T.