About EOS and r27 missile in Su27S and Mig29S

[VAOZoky]

Su-27S uses OLS27 and in its search mode limits are +-60 horizontal and -+37 vertical in wide mode and +-10 hor +-2.5 ver in narrow mode with angular accuracy of 0.08deg and max tracking of 25deg/sec. Speed of wide mode is 17 scans/sec and 30scans/sec in narrow mode. It has laser rangefinder effective up to 10km. It provides data for Slem mode +-60hor +60-14ver and in dogfights it is used for gun locks because its more accurate then radar. Its max lock range is ~30km depending on target aspect.

 

MiG29S uses KOLS and in wide search mode limits are +-30 hor +-15 ver and in narrow +-15 hor and +-15ver. Search speed is same as OLS27 as is laser rangefinder and slem mode. Max lock range is ~20km. Accuracy is 0.15deg with max tracking of 35deg/sec. It's smaller and its weight is half of OLS27. It's optimized for dogfights.

 

About r27 missile, its seeker is turned on only after its been guided via datalink and near the target. So if the target is tracked with EOS pilot can fire r27r/er and turn radar on when missile has reach terminal faze of flight.

In radar TWS mode pilot can track 10 targets but engage only one in Su27S (two targets in MiG29S) with the same principle. Both Su27S and MiG29S have TTI timers.

[falcon_120]

I don't think the r27 r/er can be launched witha EOS lock, as it requires MCU via datalink.

This can only be accomplished with a radar lock.And as far as I know the alamo is a semiactive

missile so it doesn't activate his seeker like a amraam or r77 does, his seeker is rather a passive one that receive the radar energy reflected by the target being painted by the launcher's radar.

[VAOZoky]

I never said that r27 is active. It needs the target being painted by the launcher's radar in terminal faze only! Until then its guided via datalink. That's why EOS or TWS tracking can be used to provide target info via datalink to r27r/er in mid-course. After that radar goes in SST lock mode and missile is guided accurately to target. And most importantly target will get no missile warning until SST lock is acquired which occurs in terminal faze only.

Edited November 15, 2012 by VAO*Zoky

[Kuky]

I've been wondering about wether R-27R/ER guidance in sim was off for ages, because I keep reading on few places on the net (which could be wrong anyway) that R-27R/ER have 2 stages of guidance, first the inertial guidance where missile will not be homing onto launching aircraft's radar signal and reflection of the locked target, and only in terminal phase homing guidance is turned on for better accuracy.

 

If there is guaranteed evidence that R-27R is indeed using inertial guidance at first stage of flight (just to get near the target) then it makes absolute sense that this missile will also use loft trajectory and should not be giving out missile launching warning to the targeted aircraft as during the inertial guidance stage the missile is NOT being homed/guided by the radar.

[Dudikoff]

If there is guaranteed evidence that R-27R is indeed using inertial guidance at first stage of flight (just to get near the target) then it makes absolute sense that this missile will also use loft trajectory and should not be giving out missile launching warning to the targeted aircraft as during the inertial guidance stage the missile is NOT being homed/guided by the radar.

 

AFAIK, the missile receives updates from the launching aircraft's radar during the initial phase and for that you need a radar lock.

[Kuky]

AFAIK, the missile receives updates from the launching aircraft's radar during the initial phase and for that you need a radar lock.

 

Yes, radar lock needs to be there, the targeted aircraft should be getting lock warning, then the missile is launched but there should be no launch warning as missile would not be in homing guidance at this point but inertial guidance.

[159th_Viper]

Yes, radar lock needs to be there, the targeted aircraft should be getting lock warning, then the missile is launched but there should be no launch warning as missile would not be in homing guidance at this point but inertial guidance.

 

Surely there is no difference between STT lock radar signal and post-missile launch radar signal, yes? IRL, that is, not in-SIM.

Edited November 15, 2012 by 159th_Viper

[Dudikoff]

I never said that r27 is active. It needs the target being painted by the launcher's radar in terminal faze only! Until then its guided via datalink. That's why EOS or TWS tracking can be used to provide target info via datalink to r27r/er in mid-course.

 

And how do you think this datalink works? The radar system sends the updates to the missile and needs a lock on to get the target data (I guess it is not advanced enough to provide such information from the limited TWS mode). EOS is not integrated with the radar system and it can't provide any range information so it's really useless in this regard.

[Kuky]

There should be a difference, in inertial guidance missile is not guided by the radar so radar should not be transmitting signal to guide it and targeted aircraft rwr should not be able to tell the difference... Only when missile goes into terminal stage missile starts homing onto radar signal for more accuracy and that should then give different radar signal to target aircraft rwr... The theory of it at least to me makes sense. This inertial guidance is used for cruise and ballistic missiles also but since they don't need high accuracy to hit the target... So missile in this stage does not receive any signal from anywhere. If this is the case with SARH R-27 then it should follow same principle. But then again I don't have reliable source that R-27 uses inertial guidance at first stage of flight... Or likely if target is already close then it would make sense to go homing strait away, same as actives go actives straight away if already close.

[Dudikoff]

Yes, radar lock needs to be there, the targeted aircraft should be getting lock warning, then the missile is launched but there should be no launch warning as missile would not be in homing guidance at this point but inertial guidance.

 

I don't think the radar signals change (as this is monopulse guidance so there's no CW mode like in e.g. earlier Sparrow models) - the target is locked and tracked, the missile gets its updates and the radar emits the same signals throughout the engagement - when the missile gets close enough so that its seeker starts receiving the radar echoes from the target, it starts guiding autonomously.

 

Now, this is all IMHO and I'm no expert so I'll be glad if somebody steps in and writes it in detail how it *ACTUALLY* works.

Edited November 15, 2012 by Dudikoff

[VAOZoky]

AFAIK, the missile receives updates from the launching aircraft's radar during the initial phase and for that you need a radar lock.

 

Like i said in first post IRL pilot can acquire target with EOS and lunch SARH missile. EOS will provide initial target info and after that missile enters INS guidance. When missile comes near the target radar on launcher's plane is switched on and goes into STT mode so that missile can be guided accurately to target. Missile can receive datalink update mid-course but datalink refresh speed is ~60s

[Dudikoff]

There should be a difference, in inertial guidance missile is not guided by the radar so radar should not be transmitting signal to guide it and targeted aircraft rwr should not be able to tell the difference...

 

Pure inertial guidance would be useless if the target changes course as it would put the target out of the missile's passive seeker's cone, so the missile gets continuing mid course updates and for those you need a constant lock.

[159th_Viper]

Like i said in first post IRL pilot can acquire target with EOS and lunch SARH missile. EOS will provide initial target info and after that missile enters INS guidance. When missile comes near the target radar on launcher's plane is switched on and goes into STT mode so that missile can be guided accurately to target. Missile can receive datalink update mid-course but datalink refresh speed is ~60s

 

I am assuming that your allegation is therefore that this is not happening in-SIM and is a bug?

 

Do you have any proof so I can enter a bug report?

[Dudikoff]

Like i said in first post IRL pilot can acquire target with EOS and lunch SARH missile. EOS will provide initial target info and after that missile enters INS guidance. When missile comes near the target radar on launcher's plane is switched on and goes into STT mode so that missile can be guided accurately to target. Missile can receive datalink update mid-course but datalink refresh speed is ~60s

 

You won't happen to have any evidence to support such claims (other than some hear-say story from some pilot)?

 

As that old EOS can't provide any range information and is not very precise, I really doubt that they would integrate it with a LOAL missile.

Edited November 15, 2012 by Dudikoff

[VAOZoky]

I am assuming that your allegation is therefore that this is not happening in-SIM and is a bug?

 

Do you have any proof so I can enter a bug report?

 

I'm not accusing anyone and I didn't open this topic for bug report. I just have read something and wanted to share with fellow simers :)

[VAOZoky]

You won't happen to have any evidence to support this (other than hear-say from some pilot)?

 

I don't know any Su-27 or MiG-29 pilot. I have found all this here

 

http://books.google.rs/books?id=l-DzknmTgDUC&pg=PA169&lpg=PA169&dq=OLS-27+irst&source=bl&ots=2sfLJXnaKh&sig=9xkSE4ZCtbYyJujNccqHC7fki5U&hl=en&sa=X&ei=uBukUNjKMoaTswaZw4C4DQ&ved=0CFQQ6AEwCg#v=onepage&q=OLS-27%20irst&f=false

 

This book is in line with every other piece of info that i found on internet. If you do have some other source of info please post it. I'm hungry for knowledge :smartass:

[Dudikoff]

I don't know any Su-27 or MiG-29 pilot. I have found all this here

 

Hmm, I guess that's a book written by an analyst in the 80s and then updated from time to time so it's very possible that there's a lot of stuff from the 80s remaining as this story sounds exactly like some analyst speculation - it might make logical sense that such a thing is possible to be done, but realistically it's not a viable thing to develop due to the limited range of the EOS system, the lack of integration with the radar system and the limited capabilities of the radar system.

[VAOZoky]

If you have anything better please post

[159th_Viper]

I'm not accusing anyone......

 

Yeah I know :)

 

It's just important that if there is something amiss and we have documentation to substantiate, that we attend to it so that all is well in our SIM world.

[Sov13t]

It is absolutely not possible to launch an R/ER with OLS as primary channel.

 

In order for the R/ER report launch authorized the missile has to synchronize with the onboard radar the following information: radar's missile guidance frequency (litera), target parameters especially closure rate which requires accurate speed which in turn is processed through the onboard radar's doppler calculations. These parameters are vital for proper INS computations prior to launch. Only once all of this has been processed and synchronized with the missile does the missile report readiness to the weapons computer and the green light goes on for launch. This process takes ~2 seconds.

 

As already mentioned the OLS lacks accuracy outside of about 10-15km (which by this range the R/ER will require radar on anyways for active seeking), is weather sensitive and will not be able to provide radar frequencies/corrections post launch - all resulting in poor to no chance for the missile.

 

In terms of navigation the R-27R(ER) missiles utilize two stage guidance. First stage is inertial guidance with possibility of radio corrections (what we have in FC2/3) [this is not a must, as the missile already has a "point" out there in the sky to which it will fly before activating seeker] but having radio correction improves accuracy and allows to negate effects of the targets maneuvering outside of the seekers gimbals by the time the missile reaches the precomputed point. Second stage is proportional-guidance (not sure how well this is realized in FC2/3 - but looks pretty damn close).

[Ironhand]

If you have anything better please post

Well...here would be another "source" supporting your source: R-27 (AA-10) Medium-Range Air-to-Air Missile (2nd paragraph under DESIGN). The problem with the internet, however, is that when data is scarce, often the same source can be used multiple times without a reference so that it seems that multiple sources agree, when it's really the same source being used multiple times. SO, if that one source is wrong...

 

OTOH, the R-27ET in an older version of the sim could be launched at long ranges because it was assumed to have inertial guidance. Further research on the devs part, suggested that this was not true and, so, the version of the R-27ET we have in the sim today has been kneecapped and limited to when it's IR seeker can "lock".

 

 

Rich

Edited November 15, 2012 by Ironhand

[Kuky]

http://warfare.ru/db/linkid/1655/catid/242/

 

In 1973, the front-line MiG-23s were equipped with two versions of an R-23 medium-range missile: the R-23R with a semiactive RHH and the R-23T using a passive IRHH. The missile could engage the most diverse targets, including fighters, bombers, cruise missiles, and those maneuvering with up to 5 g on pursuit and collision courses. The missile could engage flying targets at altitudes ranging from 0.04 to 25 km. Until then no radar-guided missile could ever defeat low flying targets against the earth background and no IR-guided missile could do the same on a collision course. The maximum launching range of the missiles was 27 km for head-on and 15 km for tail-on attack of targets. The target kill probability with a single missile was 0.7.

 

 

 

 

R-73 missile

 

 

In 1981, a modernized version of this missile, the R-24, entered service. It was also produced in two advanced versions. Improvements included the ability to attack targets moving with maximum accelerations of up to 8 g, and maximum head-on and tail-on attack ranges reaching 50 and 20 km, respectively.

 

In 1970, the DB began designing the first air combat missile. Designated R-60, the missile was intended to destroy enemy aircraft possessing high-maneuver capability. The missile was adopted for service in 1973.

 

In 1978, it was modernized (R-60M). The modernized version, fitted with a passive IRHH, is capable of intercepting targets maneuvering with accelerations of 8 g. It permits all-aspect tail-on attacks on targets. Its minimum launching range is 200 m and the maximum one, 7.2 km. Combat employment altitudes range from 0.03 to 20 km. The R-60M can be fired from a maneuvering carrier with no effect on the aircraft agility. The probability of killing a maneuvering target with two missiles is 0.7. The availability of a special-purpose rail-type launcher allows the R-60M to be fired from virtually all domestic aircraft, combat helicopters being no exception.

 

The R-40 missiles fitted with a semiactive RHH and passive IRHH were developed in 1972 for use with the MiG-25P fighter-interceptor and intended to engage high-altitude fast-moving and low-flying targets, such as aircraft and cruise missiles, over a wide range of combat employment conditions, in enemy fire and jamming environment.

 

With its high thrust-to-weight ratio and good ballistics, the R-40 missile attains speeds in excess of Mach 5, which required the need to use, for the first time, titanium as a building material for the missile airframe and solve a number of other technical problems relating to accessory cooling and creation of a fairing that could resist the kinetic heating. For the first time, glass ceramic was used as material for building RHH fairings.

 

The maximum altitude of combat employment of the missile against high-speed air targets is 30 km for tail-on and 27 km for head-on attack of the target. The maximum target search range is 35 km. The maximum acceleration of targets to be attacked with the missiles is 2.5 g.

 

The year 1980 witnessed the completion and adoption for use by the air defense MiG-25PD fighter of a modernized version of the R-40 missile, the R-40D, also available in two versions. Each boasted improved performance characteristics, including a maximum launching range of 60 km with in-flight RHH lockon, interception of targets performing maneuvers of up to 4 g and low-flying targets against the earth background, and enhanced noise immunity.

 

In 1985, an R-40D1 missile became operational. The missile had more advanced control and armament systems. The IR guided versions of the missile (R-40TD and R-40TD1) form part of the armament of the MiG-31 interceptor.

 

In 1980, the MiG-31 fighter-interceptor was armed with an R-33 long-range missile fitted with a semiactive RHH. The specific feature of the missile was its slender wings and control surfaces that could be folded to allow the missile to half-sink into the recesses provided in the aircraft belly. As in the case of the R-24R, the homing head of the R-33 locks onto the target after launch. The length of the flight leg preceding the missile entry into the self-guidance phase (the inertial guidance leg) may reach 10 to 20 percent of the total flight path. The missile structure extensively uses titanium alloys. The missile can intercept targets flying at altitudes of up to 28 km and engage those performing maneuvers of up to 4 g with a kill probability of 0.6 to 0.8. The maximum launching range of the missile is 120 km.

 

In the mid-1970s, the DB team turned their attention to development of the third generation missiles, the R-27 and R-73. These missiles were developed as part of a program to create a unified armament system for the MiG-29s, Su-27s and their modified versions.

 

The R-27 and R-27E missile systems are largely unified, differing in the types of powerplant modules. Both missile modifications are fitted with replaceable homing head modules: semiactive RHH and passive IRHH. The modular design of the missiles made it possible to develop systems boasting quite unique characteristics, unparalleled in foreign practice. The R-27 system can engage assigned targets in any weather using all directions for head-on or tail-on attacks on highly maneuverable air targets against the background of land and sea, in a fire and jamming environment, thereby preempting enemy carrier aircraft.

 

 

 

 

RW-AE missiles

 

 

The agility, that makes up for all its effectiveness, allows the R-27R missile to surpass its foreign counterparts, while the R-27RE outperforms and outmaneuvers them at least 1.5 times. The R-27 (R-27E) missile can intercept targets at altitudes of 0.02 to 25 (27) km. The radar guided version, whose inertially corrected control leg accounts for 50 to 60 percent of the entire flight path, can be launched in the forward hemisphere to a range of 80 (130) km. The missile can engage various types of air targets, including fighters, bombers, helicopters, cruise missiles including those capable of maneuvering with an acceleration of 8 g. The single-shot target kill probability is 0.6 to 0.8.

 

The developers of the R-73 missile sought to create a weapon allowing the carrier aircraft to achieve superiority over enemy fighters in a dog fight, i. e., the weapon allowing the pilot to realize the "fire and forget" principle without affecting the maneuverability of his air-craft. This goal has been achieved by creating a unique missile boasting a combined gas-dynamic control, which, in addition to the traditional aerodynamic controls at the motor nozzle portion, has a gasdynamic control unit producing a lateral force resulting from gas jet deflection. The missile offers the best compromise on short-range and close air combat weapons. In terms of performance it largely surpasses the existing missiles of similar types, including all versions of the Sidewinder.

 

The R-73 has a highly sensitive passive IRHH capable of locking onto the target, while attached to its hardpoint under the carrier. Apart from fighters, the missile can be used with other types of aircraft (strike planes, helicopters) that need light weapons and, most important ly, do not have sophisticated sighting systems on board.

 

The R-73 is capable of engaging any air targets flying at altitudes ranging from 0.02 to 20 km, by attacking them from astern or ahead. The maximum launching range of the missile is 30 km; the minimum one, 300 m. The maximum acceleration of the targets that can be engaged by the missile is 12 g.

 

 

 

 

R-73, RW-AE missiles

 

The advent of the missile with a gas-dynamic control allowed the designers to come over to the development of a special-purpose missile intended to defend the parent air-craft's rear hemisphere and launched in the rearward direction (the retrofired missile). The construction of such a missile required the designers to solve a host of absolutely novel technical problems, including those involved in the flight of a missile launched with its stern forward, the stability and controllability of the missile at this leg of the flight and when its speed crosses the zero point, the effect of the aircraft engine gas jet upon the missile and homing head, etc. A considerable amount of research and experimental work allowed the DB to build and test fire a retrolaunched missile developed from the basic R-73.

 

In 1984, the tactical aviation and air defense aircraft received a fourth generation medium-range missile designated RVV-AE. The advent of this missile is a milestone in the evolution of Russia's missile building industry.

 

The missile uses an active RHH. After locking on the target, it can do without target illumination by the carrier-borne radar thereby allowing the carrier to break away. The missile-home equipment includes miniaturized computers using latest target data processing techniques providing for in-flight readjustment of the guidance system parameters and better adaptation to the fluid combat situation and effects of natural and man-made interferences. Therefore the new generation missiles are usually called "intellectual" weapons.

 

Another distinctive feature of the missile is its small lateral dimensions due to slender wings and folding gridwork control surfaces, which permits the attachment of a greater number of external stores and location of the missiles inside the aircraft. The use of the gridwork control surfaces, unprecedented in world practice, made it possible to employ an electric control actuator.

 

The missile has a combined guidance system. At the initial leg, which accounts for up to 80 percent of the flight path, the missile is inertially guided. Once the target is locked on by the homing head, the missile enters the self-homing phase.

 

The use of a compact missile motor with a high power-to-weight ratio assures a maximum launching range of 100 km. The missile can kill targets maneuvering with accelerations of up to 12 g at altitudes of 0.02 to 30 km.

[Sov13t]

Su-27S uses OLS27 and in its search mode limits are +-60 horizontal and -+37 vertical in wide mode and +-10 hor +-2.5 ver in narrow mode with angular accuracy of 0.08deg and max tracking of 25deg/sec. Speed of wide mode is 17 scans/sec and 30scans/sec in narrow mode. It has laser rangefinder effective up to 10km. It provides data for Slem mode +-60hor +60-14ver and in dogfights it is used for gun locks because its more accurate then radar. Its max lock range is ~30km depending on target aspect.

 

Yes, the 27 has two modes Wide and Narrow. Wide mode provides a scan zone of 60˚x10˚ and can be slewed ±30˚ in azimuth and from -10˚ to 55˚ in vertical. Narrow mode provides a scan zone of 20˚x5˚ and can be slewed ±50˚ in azimuth and from -12.5˚ to +57.5˚ in vertical plane.

[Dudikoff]

In terms of navigation the R-27R(ER) missiles utilize two stage guidance. First stage is inertial guidance with possibility of radio corrections (what we have in FC2/3) [this is not a must, as the missile already has a "point" out there in the sky to which it will fly before activating seeker] but having radio correction improves accuracy and allows to negate effects of the targets maneuvering outside of the seekers gimbals by the time the missile reaches the precomputed point. Second stage is proportional-guidance (not sure how well this is realized in FC2/3 - but looks pretty damn close).

 

Do you have any info on what happens when the radar lock is lost and then regained? Would the launching airplane's radar system still be able to provide mid course updates or the contact with the missiles would be lost and only the last (or original) navigation point would be followed until the missile receives the target echoes or self destructs.

 

Also, is the missile's passive seeker active immediately or there is some fixed timeout till activation or there is some calculated timeout? I mean, is there like a predetermined switch between the two guidance methods or the system does it automatically when the seeker starts receiving radar echoes?

[GGTharos]

That is incorrect. You must launch the missile in STT or the radar will not generate the MCU. If you attempt to launch in EOS the launch is inhibited, and if you override it, switching back to radar will not generate MCU's because you did not send the launch signal to the radar.

 

I never said that r27 is active. It needs the target being painted by the launcher's radar in terminal faze only! Until then its guided via datalink. That's why EOS or TWS tracking can be used to provide target info via datalink to r27r/er in mid-course. After that radar goes in SST lock mode and missile is guided accurately to target. And most importantly target will get no missile warning until SST lock is acquired which occurs in terminal faze only.