Confussion with the R-73 missile family

[ResonantCard1]

Hello, I've been looking for information about the R-73 missile. I found Yefim Gordon's "Russian Aircraft Weapons Since WW2" book, where he talks about the R-73 missile. He specifies an OBS (off-boresight) angle of 60º for the baseline R-73 and an R-73E variant, with more range. I kept digging and ended in the russian wikipedia, which noted 2 different variants of the R-73, RMD-1 and RMD-2. Thing is, Yefim never even mentioned these, and the RMD-1 version appears to have way less OBS angle, 45º. These numbers are corroborated by this page, but I don't know how good is it as a source. The OBS angle of 60º, coupled with the weight and range of the variant, fit the R-73E version mentioned on Yefim's book, while the baseline R-73 version fits the weight and range data on the page but not the OBS angle (45º in the page, 60º according to Yefim). In both the book and the wiki page, the R-73M appears to have the same OBS angle of 90º.

 

There seems to be some confussion about the variants here, and while it appears that we have the R-73 RMD-2 variant (according to the OBS angle) it'd be nice to know the exact variant modelled, and how do these variants work. If the RMD-1 was an interim/development version, etc.

 

 

Also, now that we are at it, according to the Su-27SK manual, you can use the missile's seeker to lock a target, independently from the IRST. Would this mean an Su-27 equipped with R-73M missiles would be able to lock targets up to 90º OBS, even if the IRST is limited to 60º?

[Seaeagle]

AFAIK there is only one version of the R-73 in service with the Russian airforce and it has seeker off-boresight(gimbal limits) of +/- 45 degrees.

 

The R-73E is just the export version. Recently this has been advertised in two versions - one with radio fuse and another with laser fuse(R-73EL), but otherwise they have identical characteristics.

 

http://eng.ktrv.ru/production/military_production/air-to-air_missiles/raketa_r-73e.html

 

In addition to those, there is a new upgraded version called RVV-MD(which basically stands for "short range air-to-air missile") that also comes in a version with radio fuze and another with laser fuze - it has a little better range and a new improved seeker with +/- 60 degrees gimbal limits. However, AFAIK this version is not yet operational.

 

http://eng.ktrv.ru/production/military_production/air-to-air_missiles/rvv-md.html

 

Anyway, as with most Russian missiles, erroneous designations(such as "R-73M", "R-74" etc) for all sorts of would-be variants are flying around on the internet, but most are bogus.

 

Also, now that we are at it, according to the Su-27SK manual, you can use the missile's seeker to lock a target, independently from the IRST. Would this mean an Su-27 equipped with R-73M missiles would be able to lock targets up to 90º OBS, even if the IRST is limited to 60º?

 

No the R-73 has no INS and must lock on to target with its own seeker prior to launch. The seeker can be pointed to direction of a target via different means - radar, EOS or helmet sight, but the target must be within the gimbal limits of the seeker in order for it to be able to lock on to it.

Edited May 30, 2020 by Seaeagle

[ResonantCard1]

AFAIK there is only one version of the R-73 in service with the Russian airforce and it has seeker off-boresight(gimbal limits) of +/- 45 degrees.

 

The R-73E is just the export version. Recently this has been advertised in two versions - one with radio fuse and another with laser fuse(R-73EL), but otherwise they have identical characteristics.

 

http://eng.ktrv.ru/production/military_production/air-to-air_missiles/raketa_r-73e.html

 

In addition to those, there is a new upgraded version called RVV-MD(which basically stands for "short range air-to-air missile") that also comes in a version with radio fuze and another with laser fuze - it has a little better range and a new improved seeker with +/- 60 degrees gimbal limits. However, AFAIK this version is not yet operational.

 

http://eng.ktrv.ru/production/military_production/air-to-air_missiles/rvv-md.html

 

Anyway, as with most Russian missiles, erroneous designations(such as "R-73M", "R-74" etc) for all sorts of would-be variants are flying around on the internet, but most are bogus.

 

 

 

No the R-73 has no INS and must lock on to target with its own seeker prior to launch. The seeker can be pointed to direction of a target via different means - radar, EOS or helmet sight, but the target must be within the gimbal limits of the seeker in order for it to be able to lock on to it.

 

So according to you, the R-73 we have in-game is actually the RVV-MD? However, the R-73 we have in game fits the description of the R-73E provided by Yefim (mass and seeker limits, haven't actually checked its range) and the RMD-2 description provided by the aforementioned site. Plus, if the RVV-MD was showcased in 2009, how can we have it in-game?

[Seaeagle]

So according to you, the R-73 we have in-game is actually the RVV-MD?

 

I seriously doubt that - what makes you think that it is?

[ResonantCard1]

I seriously doubt that - what makes you think that it is?

 

The fact that our R-73 has 60º OBS

[TaxDollarsAtWork]

In game the R-73 is a little odd,

The gimbals on the rail are 45 degrees but in flight that becomes 75

You can see this in the files as the Fi_Start and Fi_Escort numbers which are in radians as .79 and 1.31 respectively

 

Though, you can launch over ride and shoot as far up 60 degrees off the nose and the missile will have no problem making the turn or tracking which mimics the RMD-2

[Fri13]

Also, now that we are at it, according to the Su-27SK manual, you can use the missile's seeker to lock a target, independently from the IRST. Would this mean an Su-27 equipped with R-73M missiles would be able to lock targets up to 90º OBS, even if the IRST is limited to 60º?

 

IRST system is just a another system next to radar that you can use to find targets, calculate range (laser in this case) or use as source for weapons to get them look at that direction.

 

So nothing denies you to use just the missile own IR seeker to find an target and then uncage its seeker to stay on target while IRST doesn't even work. But the IRST is far better to find targets and look around than missile seeker when it comes upward positions, while missile seeker can find from under the nose.

[Airhunter]

That's how it should be. The first variant 73's were 45° lock and 75° track after launch. From the early 2000's the RuAf has received an upgraded variant capable of 60° off bore and 75° tracking after launch. There is no different designation officially, it is still being referred to as the R-73 by both the aircraft avionics and personel. We have the first (early) variant in DCS.

 

A 90° variant is still in early prototype/R&D stages and is not fielded operationally as of today in any airforce.

[Seaeagle]

In game the R-73 is a little odd,

The gimbals on the rail are 45 degrees but in flight that becomes 75

You can see this in the files as the Fi_Start and Fi_Escort numbers which are in radians as .79 and 1.31 respectively

 

Well I believe that it is +/- 45 degrees lock limit(when the missile is sitting on its rail) and +/- 60 in flight, so I guess me calling it "gimbal limit" was a little off. Anyway, I suppose the lock limit is imposed to ensure that the missile actually has time to re-orient itself with the target after launch - i.e. you can imagine that if you lock the target at the seekers absolute gimbal limit, it may very easily "gimbal out" and loose the target.

 

Though, you can launch over ride and shoot as far up 60 degrees off the nose and the missile will have no problem making the turn or tracking which mimics the RMD-2

 

I doubt such a feature exists in RL.

[Seaeagle]

...From the early 2000's the RuAf has received an upgraded variant capable of 60° off bore and 75° tracking after launch. There is no different designation officially, it is still being referred to as the R-73 by both the aircraft avionics and personel.

 

Well I would have to reserve the right to be sceptical about that :) - where did you find evidence of this?.

 

A 90° variant is still in early prototype/R&D stages and is not fielded operationally as of today in any airforce.

 

As far as I can tell, that pretty much sums up the situation concerning the 60/60 variant(RVV-MD).

[TaxDollarsAtWork]

Well I believe that it is +/- 45 degrees lock limit(when the missile is sitting on its rail) and +/- 60 in flight, so I guess me calling it "gimbal limit" was a little off. Anyway, I suppose the lock limit is imposed to ensure that the missile actually has time to re-orient itself with the target after launch - i.e. you can imagine that if you lock the target at the seekers absolute gimbal limit, it may very easily "gimbal out" and loose the target.

 

 

 

I doubt such a feature exists in RL.

 

Yes if its going to depict a RMD-1 it should be 45/60 not 45/75

I know such a feature isn't real, its a game bug

[Airhunter]

Well I would have to reserve the right to be sceptical about that :) - where did you find evidence of this?.

 

Know some dudes. Also, search around on the web I'm sure that alignes with what I said.