Vympel R-13M - The Initial Step Forward

[S3b5]

Would you like to see this in-game?

• Yes
• No

More Polls Below

This is a suggestion about the R-13M. While technically in the game, the R-13M has been added and removed several times, and so is somewhat unknown to those who did not play during the times when it was around. As of the time of writing, the R-13M is currently not useable. This suggestion hopes to make a case for it’s permanent addition to the game.

R-13M
NATO: AA-2D Atoll
The first improved version of the R-3S

R-13M on display, note front fins

Background
Following the introduction of the R-3S in 1962, it was realized that the weapon system had some shortcomings. While a very good, and practically identical, analogue to the AIM-9B it was based on, the weapon needed some improvements as technology advanced. Even before the R-3S had been introduced, the USN had realized the same thing, and developed and deployed the AIM-9D.
Unlike the AIM-9B, and the R-3S based on it, the AIM-9D used a nitrogen-cooled seeker coupled with a higher frequency optical system, improvements to the maneuverability through more powerful actuators, and a better motor. This led to a moderately more advanced missile than the AIM-9B, and it was introduced in the late 50s.
Luckily for the USSR, while their designers were puzzling over how to improve the R-3S, they would get an unexpected boon from the West, just as had happened previously with the AIM-9B. Between 1965 and 1967, a number of Sidewinders were recovered from crashed US aircraft in Vietnam and shipped to the USSR, particularly the AIM-9D. Of note to the USSR was the new nitrogen-cooled seeker, along with the more transparent seekerhead, which gave the AIM-9D longer range over its predecessor. Official development on an improved version of the K-13A (R-3S), designated K-13M, began in November, 1967, and was entrusted to Vympel (OKB-134), with the stated goal of matching or exceeding the performance of the AIM-9D.
Despite development having just commenced, some K-13M models were ready for wind tunnel testing by the end of the year. However, work was suspended in 1968 due to the unavailability of the nitrogen-cooled seeker that was to be implemented. Development resumed in 1969, and following a few ground-launch tests, a new indigenous seeker, the INEY-68, was fitted. At the same time, other development missiles were fitted with the improved INEY-70 seeker. Both the INEY-68 and INEY-70 were nitrogen-cooled, PbS seekers, and 21 test missiles would be launched during the first phase of testing, which completed in 1971. These tests resulted in the INEY-70 being chosen for the missile. Compared to the R-3S’s TGS-13K seeker, the INEY-70 featured a smaller seeking FoV (2.4°), and retained the post-launch FoV (28°). The second phase of testing saw another 36 test launches, and ended in 1973.

The K-13M would be introduced to VVS service in early 1974, under the designation R-13M. Following introduction, it was immediately retrofitted to existing aircraft, using the APU-13MT launch rails to provide the necessary nitrogen cooling.
The R-13M would be produced from 1971-1988, and saw extensive use as the main export missile until the introduction of the R-60/R-60M for export in 1981. It was supplemented in VVS service by the R-13M1, but remained in service with many other nations.

Depiction of K-13 variants. Note the AIM-9D-style fins on the R-13M compared to the AIM-9J-style fins on the R-13M1.

Specifications

	R-13M	-	R-13M1
-		-	As Comparison
Starting Mass	87.7kg	-	90.6kg
Length	2.875m (113.18in)	-	2.876m (113.3in)
Wingspan	0.528m (22in)	-	0.528m (22in)
Diameter	127mm (5in)	-	127mm (5in)
Guidance	Passive IR	-	Passive IR
Seeker	INEY-70	-	INEY-1M
Tracking Rate	14°/s	-	18°/s
FoV (Lock)	2.4°	-	4°
FoV (Launch)	28°	-	40°	Gimbal Limit(?)
Off-Boresight	No(?)	-	Yes	Conflicting information on if R-13M was caged
Aspect	Rear	-	Rear
Lock Range (Rear-Asp)	5.5km	-	6km	Based on game stats
Lock Range (Front-Asp)	<1km(?)	-	<1km	Tested in head-on against afterburning F-4EJ (game)
Fuse	Contact and 5m Proximity	-	Contact and 5m Proximity
Launch G Limit	3.7G	-	4G
Target G Limit	7G	-	8G
G Limit	15G	-	20G	Based on game stats
Warhead	11.3kg TNT Fragmenting	-	11.3kg TNT Fragmenting
Motor	DWP-240 single stage (6,000kgf)	-	DWP-240 single stage (6,000kgf)
Burn Time	3.3s(?)	-	3.3s(?)
Speed	1,980kph (M 1.6)	-	1,980kph (M 1.6)
Range	0.9-15km	-	0.3-15km
Battery Time	54s	-	60s

R-13M vs R-13M1, and Implementation
As is present in the specifications, the R-13M and R-13M1 are extremely similar. This is mostly the reason for the R-13M’s (current) absence from the game. However, they have some differences, of note are the tracking rate, post-launch gimbal limit, and G limit. Also of note is the fact that, supposedly, the R-13M is caged. In this sense it should behave more like an AIM-9D than an AIM-9G, as the launch platform has to point at the target for acquisition.
Currently, the R-13M is modeled as uncaged, just like the R-13M1, but cannot radar slave. It is possible that there were two “versions” of the R-13M that were made due to the long production run, one caged and one uncaged, but I have found no proof of such versions, only conflicting information that admittedly may be mistranslations.
That being said, should the R-13M be (re)-implemented, I suggest it be modeled as caged. That way, the missile will actually feel like a step down from the R-13M1 and the player would notice more of a difference between the two. In that way the R-13M would feel like a proper downgrade instead of just merely a sidegrade.

Should the R-13M be caged?

• Yes
• No
• Maybe

Concerning implementation, again the reason the R-13M is absent from the game is due to its similarity to the R-13M1. The R-13M1 overshadows the R-13M just enough that it wasn’t worth it to keep the R-13M in the game, and so implementation would be tricky. I propose that, on applicable aircraft, the R-13M be in the same modification as the R-60. Furthermore, this would extend to the R-13M1 and R-60M being in the same modification as well, so that there is space for both. This would not increase the number of modifications while providing more variety to the player for what type of missile they want to use.

Using the MiG-23M/MF as an example, and omitting the R-23, it could look something like this:
Stock - R-3S (all pylons)
Rank 1 - R-13M/R-60
Rank 3 or 4 - R-13M1/R-60M(K)

The reason for this is so that when unlocking the new missile, a player can choose between a dogfight missile (R-60) or a longer ranged missile (R-13M), and again repeated with the R-60M(K) and R-13M1.
Additionally, this change should come with the caveat that the R-13M1 not be removed from aircraft that currently use it. The R-13M1 is a good all-rounder missile and is broadly comparable to the similar AIM-9G or AIM-9J, which many aircraft would otherwise lack an analogue to.

On more advanced aircraft such as the MiG-23MLA/MLD, the R-13M and R-60 should be stock on two pylons each, fully unlockable as an R-13M/R-60 mod in Rank 1, and the R-13M1/R-60M(K) in Rank 2 or 3.

Would this modification layout, or something similar, on applicable aircraft be acceptable?

• Yes
• No
• Yes, but in some other way

Conclusion
In summary, the R-13M is a (potentially) caged R-13M1 with less maneuverability and a slightly worse seeker. It’s permanent implementation would allow an intermediate level missile for some planes, and it could be used to great effect as a stock missile for others. It would serve as a great equal to the AIM-9E or AIM-9D, allowing certain planes to get a capability they may have otherwise lacked, and be a stepping stone to the improved R-13M1 and R-60M.

Sources

Wikipedia - K-13 (missile)
Hyperscale - R-13M
Ruslet.Webnode - R-13M
Ruslet.Webnode - R-13M1
Ruslet.Webnode - R-3S
Valka - K-13
Valka - R-13M
MilitaryRussia - K-13
Polot - R-13M
DCS Forum - R-13M Track Angles (Manual Page)
SecretProjects - K-13
SecretProjects - R-13M1
SecretProjects - R-60
AviaMuseum - K-13M
AviaMuseum - K-13M1
Namu - K-13
AusAirPower - Sidewinder
War Thunder Wiki - R-13M
War Thunder Wiki - R-13M1

[R_nminbiY_n]

I’m waiting for this to get added again, then removed the update later again

[WalletWorrier]

Already in the game, then removed, then readded, the removed, then readded, then removed.
All R-3S carriers except the MiG-17AS and MiG-21F-13 should receive R-13Ms, as well as the J-35XS.
The MiG-21S would need moved to 10.0 or better yet replaced with the SM at 10.3 (MF without flares) so we can get a TT 10.0 21S with R-11FS-200.
The PFM should receive APU-13-2 and go to 9.7 if not 10.0.
MiG-19PT would go to 9.7.
R-13M1 was never exported so potentially could be removed from non-soviet aircraft, or kept for balancing.
11.3+ aircraft should have 13Ms stock.

In short a decent mid-range missile for many aircraft, a better stock missile for others, and the top missile for a missing generation of aircraft (Su-20, MiG-21M, MiG-21S, etc)

[S3b5]

The circle must continue

[S3b5]

Personally I think that if the MiG-21F-13 isn’t getting it the MiG-19P/PT shouldn’t either.
As well as that, the PT was created to test the K-13, by the time the R-13M came around it would be the MiG-19P.
PFM yeah
As for the exported R-13M1 I think that it should stay on the aircraft that have it, due to the similarity in performance of that and the AIM-9J. It would also be a “progression” on those aircraft, like going from AIM-9E → AIM-9J, so I think it should stay.

[meki98]

so its an universal missile?
it feels like in Russia each plane has its own missile until the modern age
the us only has aim54 and aim9c that are specialized i think
for Russia there are r24 k8 r4 r40 r33
k5 and R-37 are a maybe they do have a number of planes that can use them but most require dedicated versions

[S3b5]

Yes, but only for the MiG-19(?), MiG-21, MiG-23, and Su-17/20/22

[WalletWorrier]

It’s a modernized R-3S and compatible on the same APU-13 series launchers as the R-3S. The R-13M was the primary IR AAM for Warsaw Pact nations from the early 70s until the mid 80s when it was gradually replaced by the R-60/M.
While many Soviet interceptors had unique missiles and radar missiles were not particularly standardized until the R-27, the USSR had pretty standardized short-range IR missiles with dam near every fighter using R-3S, then R-13M, then R-60, R-60M, and finally the R-73 and derivatives.

[F-16D_Barak_II]

R-13M should simply be introduced on lower tier aircraft that could use it that don’t currently have it like the Mig-21s, no reason for it to be on the Mig-23s since they are at too high of a BR

[S3b5]

Some of them get stock R-3S so this could replace that lol

[WalletWorrier]

I mean the 23M and MFs still have R-3S

[F-16D_Barak_II]

I mean gaijin could just outright remove the R3S but its gaijin, gotta grind for longer

[meki98]

such a terrible missile only fun thing about it is thinking about how you can mix components with the aim9b and both will still work

[WalletWorrier]

Side note: what do you mean by uncaged? Aren’t all missiles with a seeker gimbal modelled as uncaged? The R-13M pretty definitively has a 28 degree gimbal.
Or did you mean radar-slavable? In that case, no, there doesn’t seem to be evidence of this function.

[S3b5]

It may be the wrong way of looking at it (and if it is I apologize)

but I was thinking of it as the difference between AIM-9D (caged?)

and AIM-9G (uncaged)

I’m not sure if caged is the “right” word, I just didn’t know how else to describe it

[GothFemboyHooter]

mig 23s get r3rs stock… damn, who know i could feel bad for russia.

[WalletWorrier]

Yes ok that makes sense. The R-13M is said to have a 28deg tracking FoV which to me sounds like it’s uncaged. Someone would have to look into the files but I don’t think caged missiles like the 9B or D can move their seeker at all.
The description of “having to face the entire aircraft towards the target” to me just sounds like it’s not radar slavable so you do need to aim the plane directly for lock, though then you can move the nose away, pulling your 3.7g turn, to lead before firing.
So in terms of seeker type:
9D- unslaved, caged
9E- unslaved, uncaged
9J- slaved, uncaged
I think the 13M is probably like the 9E. But I don’t have any more information than you do lol

[S3b5]

I actually decided to test this.
Basically, what I was thinking was that missiles have a higher FoV post-launch. The way I tested it was by going into a custom match and trying to fire right at the edge of the seeker FoV (before it loses lock) in such a way that by the time the missile “activates” ~1.5 seconds later (starts turning) the aircraft launched at is outside of the “lock” FoV.

It seems like they do have a higher post-launch FoV; however this might be due to how they model “tracking,” which is (I think) by checking what is in front of the missile and assigning a “tracked” or “not tracked” value to it. But it depends on the game update speed, I think, which leads to some things like this:

Very obviously, the AIM-9B should not be able to track at this angle, but that’s besides the point.

I did this in the space of one custom match so it may not be the best method of testing, and I would rather someone go through the code, however I myself don’t know how to do that.
I also tried to take a few pictures from inside the missiles, facing towards the front, so that you can visualize the seeker FoV as displayed on the HUD when you are locking the missile.

Test: AIM-9B (3 Launches)

Launch 1
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Launch 2

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Launch 3

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Test: AIM-9D (4 Launches)

Launch 1

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Launch 2

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Launch 3
The only one that hit

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Launch 4

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Like I said before, it does seem like they have an “expanded” post-lock FoV. Whether that is due to game code or a real property of the missiles, I don’t know, but it exists. At least for some, notably the AIM-9B, it is very obvious it should not be able to do that as the seeker physically can’t point in those directions. But, for others, like the AIM-9D, it at least seems plausible that it does have an easier time tracking post-launch.

The reason I wanted to note this is that I think that the way the AIM-9D is modeled is the way the R-13M should be modeled. There was the one account of having to “point the aircraft toward the target,” but it made no mention of pulling the nose away and retaining the lock, at least not to my memory. Whereas on the AIM-9G, for example, we know that it was possible due to the addition of Sidewinder Expanded Acquisition Mode (SEAM), which I believe was repeated for the subsequent Sidewinders.
It very well might just be not radar slaveable, unlike the R-13M1 which is, but I don’t really know. Regardless, at least for me, I think the way to model it would be as an analogue to the AIM-9D, where it is a caged seeker but “expands” post-launch; either because it’s supposed to or because of how missiles are coded. That’s the reason why I made mention of keeping the R-13M1, since unlike the R-13M (assuming it’s modeled like this) it would be able to make an “off-nose” solution, far easier than doing the same with the R-13M.

[csla1972]

[S3b5]