The drag coefficient of four semi-recessed AIM-7M in a Streak Eagle is 15.3, that´s less than the central external pylon on a Viper without anything attached to it, expect identical numbers for Typhoon. I would be expecting those two central R-27 to have a worst drag coefficient by multiples.

A Su-27 can go ~M1.7 with 4xR-73 and 6xR-27s and full fuel load. Also such payload allows Su-27 CG switch to negative stability above ~M1.3 which is not the case for a clean Su-27s. How fast a Typhoon can go with a)10 A-A missiles? b)10 A-A missiles and sufficient fuel to chase a Su-27?

Point haavarla making is; Su-27 is already too draggy and have too much thrust to be affected by the drag of R-27. Same is not the case for Typhoon.

Has off now, the exact oposite happens, if a Typhoon drops the external fuel tanks it goes supersonic without using the burner, a vanilla Flanker is completely incapable of doing such.

Without EFTs, Typhoon won’t have enough fuel -by a long shot- to chase/outrun a Su-27; supercruise or not. To quote Gerry Gallop, a topgun instructor who flew Su-27;

Slowing the Flanker down after almost 25 minutes of supersonic flight also showed interesting results. “I take it out of burner and I’m just at mil power and the speed dropped down to–I was still supersonic,” he says. “By the time we got done, 25 minutes supersonic, I looked at the gas and go ‘you know I could turn around fly back the way I came supersonic and still have a normal amount of gas left to land’,” Gallop says. “I had more fuel when I was done that profile than a single centerline Hornet had on the ramp.”

The Flanker holds 9,400Kg (20,700lbs) of fuel, which is similar to an F-14 with two external tanks, Gallop says. “I’m up there clipping off 13 nautical miles a minute and I’m burning 110kg per minute,” he continues. “I took off with 9,400 and I’m burning 110kg per minute at Mach 1.3, so you look at that and go ‘I can be supersonic a long time and you look at how many miles you can fly at that speed.'”

According to this, Su-27 can maintain supersonic flight for 50+ minutes at M1.3, makes 1300 km. For how long a Typhoon can supercruise with full internal fuel?

Indeed the initial tests from firings of the R 40 by the MiG 25 were highly cumbersome, and demanded the development of the specific operational mode, since at high Mach speed should be necessary to launch two R 40 missiles simultaneously from MiG 25 , and each of those missiles would be launched from each wing, in order to avoid the loss of the aerodynamic stability due to asymmetry caused by launching from a single missile of sole wing.

IIRC the problems encountered with MiG-25 was not when firing a single R-40 missile, but firing two in quick succession destabilized aircraft too much that ailerons couldn’t counter the alternating rolling motions. That was solved during test flights when MiG-25 prototypes were modified so that elevators also acted as ailereons during missile launches (elevons). After that there was a hyrdrolic pressure issue where elevons wasn’t moving fast enough to stabilize the aircraft at certain speeds, so the actuators were repositioned to enable MiG-25 firing its missiles safely at all speeds. In any case, such issues were already solved when MiG-25 introduced, it shouldn’t be a problem with MiG-31.

I thought the Su -27SM gained weight as it was certified for heavier ordinace(at senter hardpoint)?
Also it include the AL-31FM1 with more thrust, and re-enforced MLG for increased MTOW. IMO, the whole airframe is strenght is increased.

I don’t think the digital instrumentations and newer subsystems makes the total weight any less.

Even the earlier prototypes of T-10S took of with 32xFAB-250s and a pair of R-73s. On different loadouts Su-27S can carry 5 or 6xFAB-250s on each of stations 1,2,9,10,3,4. That is (including the MER itself) more than 1500kg for each pylon. There is simply no need for strengthening airframe for the rated ordnance of SM. For a cost-effective upgrade I don’t think they would modify the airframe.

With appropirate bus and wheels, Su-27S can reach 33 tons MTOW without any airframe modifications. Othervise it is 28 tons. What is the MTOW of Su-27SM?? Perhaps instead of airframe modifications some additional wheel sets introduced?

I agree newer subsystems wouldn’t decrease weight much, but it wouldn’t increase it either. In any case, not enough to say Su-27SM should weigh noticably more.

F-15C PW-100 engined are 12700 kg, PW-220 engined are 13380 kg IIRC. JSR is the only guy in this world to claim Su-27 has best, T/W, because in no comparison it is the best.

4th gen, 50% fuel;

F-16>MiG-29>F-15>Su-27>M2k

Fuelled for 1000 km range;

F-15>Su-27>MiG-29>F-16>M2k

Fuelled for pure 10 min AB time (airshow);

F-15>Su-27>F-16>MiG-29>M2k

MTOW;

MiG-29>Su-27>Rafele>F-15C>F-16>M2k>Tornado

^ These data are taken from flight manuals with simplest calculations; Some rough estimates (by range and full AB fuel consumption data) done by me;

Ground alert interceptor (100 km flight + 3 minute combat);

F-15>Su-27>MiG-29>F-16

Combat Air Patrol (500 km flight + 3 minute combat)

F-15>Su-27>F-16>MiG-29

Fighter Sweep (1500 km flight + 3 minute combat)

F-15>Su-27>F-16>MiG-29

In equivalent missions, F-15 had always the best T/W of 4th gen fighters. (F-15 = F-15C PW-220, Su-27 = Su-27SK, MiG-29 = MiG-29A 9.12, F-16 = F-16 blk30 GE-129.)

The most interesting about its issue were that MiG 25P had been used Smerch A radar, as well as the MiG- 25PD were modernized with Sapfir 25 radar . However both radars Smerch A and Sapfir 25 were using in I / J radar band, while the Zaslon N007 radar from MiG 31B/BS has been using the X band radar frequencies.

What has been making even more ‘tricky’ understand this option about to use the R 40TD, since that MiG 31B/BS should replace one R 33 from max load of four R 33 by an external pod APP 46TD with function to provide command link to R 40TD, once the radar Zaslon N007 did not operate with the frequencies of the command link from R 40TD .

I think there is an error regarding to “standards” about radar sets. An I-J band radar operates at same frequency as an X band radar.

X-Band is a IEEE defitinion, that includes frequencies from 8 to 12 GHz. I-Band is a NATO defition that includes frequencies from 8 to 10 GHz. There is no hardware constraint that prevents Zaslon from operating R-40.

IDK about APP-64TD pod, but its likely an early implementation, with additional software modifications, Zalson got the ability to guide R-40RD/TD missiles without it. Like you said there are billion pictures MiG-31 carrying R-40, most are without the pod you mentioned.

And there is no lack of options to replace the R 40 in the MiG 31 during the 80’s, once the Soviet Union had put in mass production the Alamo AA 10 C / D versions with extended range , in both versions with SARH and IR seekers, besides the anti radiation air -air missile R 27P.

So the main fact that the Soviet Union had equipped its most advanced and expensive interceptor as MiG 31B/BS with AA 6 Acrid( R 40) from originally MiG 25P, rather than opt for a version of the R 27, this could show that R 40 were considered effective and probably with more range that any version of the AA 10C/D Alamo.

Again, this has to do with the MiG-25/31s operating environment, which routinely go above 65k feet. I don’t think anyone understands the importance of this;
Air density is
1,225 kg/m3 at sea level.
0,414 kg/m3 at 10000 meters (32808 feet)
0,088 kg/m3 at 20000 meters (65616 feet)

Air density is directly proportional to lift, and therefore G and turn rate of any flying object. (missile or aircraft) What this means:

Firstly; A missile like capable of pulling admirable 60Gs at sea level will be pulling only 4,3Gs at the same airpeed at 65k feet due to thin air. Launched at ~M2.5, such missile will stall the second it clears the rail, instead of making simplest turns in order to head towards its target, it will fall like a brick until it gains some airspeed.

Secondly; A R-27 or AIM-120 like missiles are relatively short burn, as slow speed at terminal approach is not necessarily a bad thing at low altitude; it would reduce turn radius, increase turn rates at same Gs etc etc. But higher the altitude is, thinner the air is. And as a result, slowing down gets problematic, because fins now work at their stall limits while maneuvering towards its target. R-40 and R-33 missiles are long burn, so they can preserve their higher speed at longer ranges, adding to their maneuverability.

To simplify; Compared to R-27 a missile like R-40 with roughly 6 times wing area, and twice weight, can *mathematically* pull 3 times more Gs at any given speed, can be launched at thinner air, and maintain its maneuverability to 1,73 (3^0,5) times slower speeds (delayed stall), at the cost of being roughly 6 times draggy. So while R-27 could reach longer ranges, R-40 can actually maneuver and kill something at long distance and high altitude.

Plus, having twice warhead weight would help too, as any attempt at 30+k feet will be near miss by any missile.

Take the Su-27, for instance. It’s normal loaded weight is at roughly 56% fuel. I suppose this makes sense since the Su-27 was allegedly designed to have massive internal fuel capacity for both range (Russia is large) and to get rid of the need for external fuel tanks. The Flanker is apparently a poor dogfighter at higher fuel loads, and I’ve heard that certain fuel tanks aren’t rated at 9 g. Only when those tanks are empty and fuel loads are at 50% or lower does it become quite an animal. Again, makes sense since the Su-27 can act as a long range fighter interceptor and by the time it arrived at combat it would’ve burned enough fuel to be at its cited normal loaded weight. I’m wondering if the T-50 has the same philosophy in its design, and if so, certainly structures and fuel tanks don’t have to be designed for 9 g, which can save some weight in structure.

Non-OWS equivalent G limit of Su-27 is calculated as such: 171000 kg is the structral limit. Not only the fuel tanks, but entire structure of aircraft is designed as such. If you want to pull 9Gs your weight will be 171000/9 = 19000 kg. At NTOW of 21400 kg, Su-27 can pull 171000/21400 = 8Gs. At 30500kgs, Su-27 can pull 5,6Gs etc etc.

Still, I wouln’t call it “poor” in terms of dogfighting, (as to reach same range virtually any other fighter would need external fuel tanks, which would degrade maneuverability much more) but your assesment is true. However every fighter is designed like this; Even F-4E or F-15 will not be pulling their maximal Gs with their full internal fuel load.

Out of curiosity, I’m wondering how fast the T-50 will be at sea level. Panavia Tornado and F-111 were quite the aircraft at low altitude, and the F-22 is apparently quite a speedster and can do Mach 1.4 on the deck.

Comparing F-15C PW-220 with F-22. Going from M1.2 to M1.4 alone results in 36% increased drag. Add to that, F-22 is certainly more draggy, has greater wing area to contriubute to drag, has fixed inlets and less T/W. Plus, it has delicate RAM which would have problems at high pressure/temperature. Somehow I don’t believe F-22 can do much better (if any) than F-15 at the deck. Likewise, I would say same for T-50 vs Su-27 too.

Well within? It’s barely within and that’s without taking into consideration the seeker’s scan speed and that the assumed 15 km IR sensor range is way too optimistic as its range depends on atmospheric conditions AND the target aspect..

Well within. R-27ET uses the MK-80 seeker same as original R-73 meaning it has same 45 degree off boresight capability. 15 degree is what is recommended in the manual for confident capture of IR seeker.

Since the missile in this case is approaching from target’s frontal hemisphere, the target’s engines are not visible and thus no way that old sensor can lock at that range (in good atmospheric conditions, a rear hemisphere shot and target using afterburners, then it might be viable).

Old sensor of R-27ET you are referring to is MK-80. R-73 missile has some 40 km rated range, I believe 15 km lock from front is pretty reasonable. If you are referring to R-40TD, its reasonable to assume it does have some frontal hemisphere coverage. However purpose of launching two missiles at once is if target makes a quick turn and breaks the radar lock (disabling the R-40R but also silencing the RWR) it will be presenting its afterburners to the R-40TD.

And this is even before considering that this assumes that the target after being locked on (the context is a Western fighter, so in the 80s it should have an RWR which can classify the MiG-25’s radar) continues flying straight on its initial course and speed (a drone basically rather than a trained fighter pilot). Granted, the missile would be launched from shorter range (as the 60 km is the claimed ideal maximum launch range for the radar variant for a head-on approaching target; the IR variant has more drag and thus somewhat shorter range), but the seeker’s head-on lock range limitation and target not being a drone arguments would still be valid.

The problem is; when both sides using 70’s radars and 70s SARH missiles, both aircraft will achieve target lock long before missile launch. Pilot has same warning from the RWR from 70-80km away until missile hits. So pilot clearly wont start his evasive maneuvers the second his RWR beeps, as he would be losing his target lock an SA; he has to see the missile first. And by the time pilot actually sees the missile R-40TD would have acquired its target.

By the way 60 km BVR range is pretty long range even by todays standards. R-27ET is not more draggy; it has lesser 52,5 max effective range (compared to ER’s 65,5), because it lacks command guidance, and cannot follow a ballistic path to its target.

If these old missiles were such an effective weapon in the described use case, one wonders why nobody in the West copied such a design after Belenko’s defection in 1976 (MICA-IR appeared only in 1998)..

Utterly idiot way of thinking. So if west doesn’t use it, then it must be useless. Why its not the opposite? That if Russians use it, it has to be useful?? West didn’t copied High off-boresight missiles, helmet mounted sights, IRST, ESA Radars, GCI/interfighter datalinks from the Russians for at least 10 to 20 years. Do none of these features make any difference too?

Regarding the other points, your manual quotes state nothing to back your scandalous claims that other MiG-31s can take over other 31s missiles’ guidance or (even worse) that the Su-27s can do it.

My quotes show Su-27 can share target tracking information with other Su-27 and merge it with their own data on sofware basis and integrated to RLPK. What you people don’t get is, taking over a SARH missile guidance is not an additional feature to add-on. On a group operation basis; if aircraft#1 locks and tracks target#1, it has to transmit its signal specifics through datalink. This is a necessity, because if aircraft#2 tracks target#2 at the same time, both aircraft must not disrupt their signals (ie, radar returns from target#2 must not interact with the tracking (or missile guidance) of aircraft#1). However, if aircraft#2 also locks on to target#1, it will also be on the same tracking specifics as aircraft#1. A missile handover is just that aircraft#1 cuts its radar lock to target#1 but aircraft#2 maintains. Missile will not even notice the difference, it will continue following to the radar returns its assigned.

Unlike ActionJackson dreams, such controllability with two-way encrypted datalinks that support both intraflight and ground based radars were not present in ANY western aircraft until the introduction of Link-16 in late 90’s. (F-14’s Link-4C could be used intra-flight, but not at the same time with Link-4A).

What made the MiG-31’s IFDL different from that of the Su-27S/P is that it allows full a/c control over the “slaves”, this means, that the commander of the group could make control directives (just like the Vozdukh-1/Lurch series of C2BM sets) and direct their aircraft towards targets and so. This is not allowable in the TKS-2-27.

Nice and informative comment, but I believe you are wrong about this one; from flight manual.

On the aircraft, which accepted target designations from another aircraft, senior on the rank, is formed the mode BN ([BP]) according to the information about the target, which entered from the transmitting aircraft.
Control of aircraft in the stage of guidance to the target according to target designation from the transmitting aircraft can be executed in the automatic or director mode.
For the transition into the director mode of induction to set the switch [NAVED] MANUAL -[AVt] on the control panel [SUV] to the position [AVT] and on the panel SAU to press button [NAVED]. Control of aircraft to accomplish by hand according to the deviation of director label (large ring) on ILS.
For the transition into the automatic control mode of aircraft to additionally press button [AVT] on the panel SAU.
The entry into the zone of the [razreshjonnykh] launches of rockets on the transmitted target is possible and with the manual steering of aircraft (without the use SAU), in this case to pilot it is necessary by the corrective turns of aircraft to hold the label of target on [IPV] on the vertical axis of symmetry [IPV].

Ok, with the R-27T/ET you can override the launch authorization and launch it hoping that the target doesn’t change course and let’s say the R-40TD supports this too, then how will it acquire a distant maneuvering aircraft? If the target is maneuvering, it will change course and get out of the missile’s limited IR seeker cone. As the missile is flying straight and not to a calculated target intercept point, it is only useful in straight head on shots, but given the IR seeker limited range and cone, it’s still generally a rather low probability shot and I’d wager to say that this makes it practically useless.

15 degree seeker cone and ~15 km detection range gives an area 7,76 km in diameter at maximum range. Let’s do some math; Assuming 2000 km/h average missile speed and 800 km/h target speed, and target puts a 30 degree closure angle. Missile launch from 60 km.
Time required for 45 km flight (so that seeker gets in range) 45km/(2000km/h+800km/h*cos30)=0,016h
horizontal deviation during elapsed time= 800 km/h *sin30*0,016h = 6,68 km; well within the seeker capabilities. At 15 km, a target without MAWS wont see the missile and start maneuvering anyway.

No, it is nonsense. And saying that Su-27 can do it too indicates that you’re making all this up (where could you find this misinformation?).

Su-27 flight manual, section 5 combat employment. To be more specific; mentioned in Subsection “5.1.2 Radar aiming complex RLPK”, specifically states a) ability to form output information to accomplish group activites b) ability to share transmision commands and control signals through “СОК-Б”, And under subsection 5.6 Attack of aerial targets in ДРБ states a missile launched with RGS but without control channel can be assigned when previously launched missile reaches its target and frees up the illumination radar.

If the target lock is broken during mid-course radio-command guidance phase, the R-27R/ER missile is lost as this radio-command link cannot be re-established. If the target lock is broken during the terminal SARH guidance phase, the missile might reacquire if the target is locked again quickly enough to still be within the missile’s SARH seeker’s view (as the missile has a monopulse seeker, not a CW one).

Breaking a target lock is different from target re-assignement. According to same manual, R-27R/ER missile apperantly shuts off if target lock is broken. (even if РГС regained, ДНП mode will not renew, it says) Possible working principle is that RLPK signals missile via mid course update, so it does not shut off and simply starts gimbaling its seeker. Missile flies unguided for a few seconds, but still active. RLPK then steers its illumination to another target, or provides control channel info to another Su-27, so it takes over.

What I am trying to say is Su-27’s radar is much more simple and primitive compared to MiG-31. MiG-31 is also much more BVR oriented than Su-27. IMHO its nothing but logical to assume MiG-31 has this kind of features too.