The R-15, at least initially, was designed to be used in a one way airframe….it was not meant to be very efficient nor be located behind a complex inlet that was designed to provide fully optimised airflow at all speeds.

You have to remember that the control laws for a 2D inlet (as the Mig 25 has) which uses upper and lower ramps to maintain the shockwave in the ‘optimium’ location rely on three compments that the Soviets (and others) were, at the time finding hard to ‘reliably create and maintain’…

The Mig-25 inlet is one of its secrets. It is very complex 2D inlet, with upper and lower ramps and duct guide tree, all intended to ensure stabilised airflow.
There is no west eqivalent to this type of inlet.
Because of this, the MiG-25 do not suffer from ‘unstarts”.

From engineering point it is a technological marvel.

the Soviets sought to intelligently avoid the problem, by using alternative solutions which provided them with the answer they wanted…unstarts are not an SR-71 only problem, they potentially affect all supersonic aircraft, try looking up the BA/AF unstarts during Concorde operations or those affecting the B-58…

The ordinary Mach 2 engines uses external compression inlets, so the normal shock wave stay in the inlet lip. It doesnt enter inlet so there can not be unstarts.

This kept the solution within the areas of known expertise (metallurgy) and avoid the need for massive research into solid state electronics etc which may have delayed the programme for relatively little (performance wise) gain in the intended role.

This is a matter of design, not metallurgy. The mixed compression propulsions (as used in SR-71 ) are susceptible to unstarts by its nature, because even the slight air density change can induce unstarts. Any fighter like maneuvers are out of the question.

I’m not sure I understand the comment about supersonic exhaust that you made. Most large turbojets (see Concorde, Phantoms, SRs etc) have a supersonic exhaust plume, so the R-15 is not unique (as far as I know) in that regard. Perhaps you meant something somewhat different.

Yes. In ordinary Mach 2 engines (J-79, R-35, F-100 etc) the exhaust gas velocity is about the same as the speed of sound in the local hot gas exhaust plume.
In the Mig-25/31 it is much higher than local exhaust speed of sound, and because of that they exhausts are called “supersonic exhausts”.

You probably did not know, but the speed of sound in the hot gas exhaust airstream is much higher than in the surrounding air.

Schorsch, you have to learn something: Firebar says the manual is old and not the right one. You have the wrong manual and I am sure the limitation of Mach 2.83 is changed to Mach 3+ in the other manual. Unfortunately we do not have it in our hands. If you would have the latter, you would also see, that the maneuver Envelope goes up to 11g Ultimate.

The 11.5 G is not service limit, for MiG-25, of course, but is it a very good indication of what the aircraft can endure without breaking.
Just as for F-4 which survived similar kind of treatment, as well.

Seriously, firebar makes claims and cannot prove them with official souces. A picture of a table in front of a museum a/c is no proof. ;

A data table in front of MiG-25 at the Indian Air Force Academy is not a proof ?

He denies the whole time that the Tomcat can engage 6 Targets with Phoenix simultanuesly

Of course I deny this.
See yourself what kind of propaganda tales we have been reading.
The AWG-9 was supposedly able to track 24 targets in TWS mode. That was a pure lie, which persists to these days.
The much more capable and modern digital APG-70, in F-14D, was capable of 10 targets track in TWS mode.!!!

I ‘think’ that what Firebar meant is that the MiG-25 engine is capable of handling a supersonic ‘inlet’ flow.

To a degree he is correct in that the first two stages of the compressor are designed to accept a transonic airflow. Certainly amongst contemporary engines globally this was a unique capability, however it was more a legacy of the original engine’s application than.

The bonus from MiG’s point of view is that the engine was able to accept a far greater range of airflow speeds, massively reducing the complexity of the inlet and associated shock wave management systems. From a conceptual, technical and operational stand point this was a very intelligent and robust solution. Sure the engine itself was not as ‘efficient’ (SFC) or as long lasting, but those were downsides that were perfectly in line with the pragmatic approach to war time operations then espoused by the Soviet militar

True. The Mig-25/31 have supersonic inlets and also supersonic exhausts.

As I said earlier, the R-15 engine has transsonic compressor, with no west equivalent.
It is in fact very clever solution, intended to avoid “unstart” problems associated with mixed compression propulsion used in Blackbirds and XB-70.

Because of that, the MiG-25/31 can perform all sorts of fighter maneuvers without fear of shoch wave pops-out of the inlet, and thrust loss.

It is unique design and, in fact, the only one possible for any efficient Mach 3 fighter.

The Russian designers, rightly, thought that it is not enough to have Mach 3 a/c which will be capable only for a streight line flights.

Got news for you. ALL jet exhausts are supersonic. About the only ones that might not be is the bypass air on high-bypass airliner engines. BTW bypass ratio of the D30-F6S is 0.55 which is higher than the Super Hornet’s

Ha,ha. Not all Sferin. You have to be familiar with jet engines to know that, so I will not criticise you.

Only a few jet engines have supersonic exhaust, because it is measured according to sound velocity in exhaust hot gas stream, not to sound velocity in atmosphere.
It is not the same.

When I say that there is no west equivalent, it is so.

BPR of D-30F6 is 0.3. It is a “leaky turbojet”.
But of course you can find all sort of data in the net.

I’d rather go with what the pilots are saying. It HAS demonstrated M1.8 without afterburner(and possibly faster), in level flight. It’s interesting how your willing to except all sorts of whimsical claims about the Mig 25, yet show a complete disregard for what F-22 pilots have observed.

You don’t believe “Defence today” ?

All right. See this:
http://www.globalsecurity.org/military/systems/aircraft/f-22-f119.htm

The fact is that the sevice version design has far more drag than prototype, which achieved 1.57 Mach dry.

The service version has 1.8 Mach max afterburner speed, but it is often mixed with dry thrust speed.

You have to understand the principles of high pressure ratios in jet engines.

Really? Is that so? Please tell me how many F-15/14/16’s the Flogger has downed?

See Syrian sources.

TF-30’s bypass ratio is 0.9, F-110’s is 0.85 that’s nowhere near to being considered as a high bypass turbofan.

For a fighter engines, these are considered unacceptably high by-pass ratio, with adverse effects on higher altitude performances.

Note the T/W ratio of an F-14B/D is unity.

It is 0.99 combat T/W for F-14D versus 1.01 for MiG-23 ML.
But bear in mind that these are static, sea level figures.

At medium and higher altitudes, the Flogger’s T/W was much, much higher, by virtue of its powerful turbojet.

Note that even F-14D was not renown for its climb rate.
The F-14A was simply awful in this respect.

Phoenix and AWG-9/APG-71 uses time sharing with multiple Phoenix launches and can support 6 missiles in flight at once. Your statement of the missile not being able to cope in a real environment is laughable as evidenced by the Iran-Iraq war.

Do you realise that the Tomcat tracked and guided missiles to 6 targets only on ONE test. Never again, on tests and certainly not in service. It was strictly controlled test, but in service it was discovered that the equipment can not cope with the real enviroment.

There are no evidence that the Phoenix was used in the Iraq-Iran war.
I put attachment about that fact, earlier.
You think that Iranians were more profficient, with Phoenix use, than Americans ??? Don’t give me that.

Mach 2.41 was reached by test pilot Joe Burke in aircraft 1X in the summer of 73 in level flight and the aircraft was still accelerating when the test was curtailed with the objective having been achieved.

The plain fairey tales. It achieved 2.4 Mach in test only. Check it.
But not in level flight. It was in shallow dive.

The F-14A Manual say: Its max level speed is 1.88 Mach, clean or with 2x Aim-9. (page 4-7)

Bill Gunston describes the F-14 as one of the most aerodynamically efficient aircraft ever built.

Except the sluggish roll rate, the fact that it was prone to non recoverable flat spin, inability for maneuvering at more than 15 degrees Alpha, etc,etc.

The Mig-23ML is cleared for maneuvering to 28 degrees Alpha. (Source:Manual).
It is more that F-16 can do.

John Boyd is part of the light fighter mafia much like Pierre Sprey – even said the F-15 was too big and he would probably hate the F-22 as well. So it’s no surprise he is not a fan of the F-14.

He did not like the F-14 because it was underpowered, as he said. A big vice for every fighter a/c.

The F-14 does not use full slats in combat, instead the slats (and flaps) automatically deploy to the manoeuvre position – 7 degrees for the slats, 0-10 for the flaps. Sidewinders can still be fired.

With Slats extended, the firing of sidewinder would cause a departure.

For the benefit of the others. J. Marmain had no other data than that of R.A. Belyakov. The group of Russian engineers responsible for that were:
MM. A.M. Savelyev, L.I. Eguenbourg, A.I. Saprikine, I.G. Soultanov and Chief constructor V.A. Arkhipov. All data, material and pics are from the archives of MiG. To celebrate 50 years of MiG 1939-1989 that official book was done by MiG. J. Marmain got the honor to have a French translation of that.

It is not true, Sens.
The book foreword say:

“The book “MIG” has been translated from the French publication.”

It is not translated from the russian. And the Russian MiG engineers have been interviewed, only.
What they exactly said to author, Jacques Marmain, we do not know.

Here is the proof: ( page 417)
-” Surprisingly the MiG-31M system operator has only two small windows.”

The Russian engineers, and particularly the Belyakov, would not say: “Surprisingly…”.