Vympel R-27 'ALAMO' - History, Design, Performance & Discussion

Drag coefficient is not unilateral to all missiles. It’s heavily influenced by caliber and other values.

The ER/ET are larger in caliber than the R/T and thus have a lower CxK value in return… they’re also longer missiles which helps to reduce drag as well.


do you have a source for R-27 being 25g’s?

The last time I showed that the Super 530D had high drag, they reduced the drag coef of both 530D and R-27ER simultaneously since both are the same caliber size. The thrust on 530D is correct. The new drag coeff on R-27ER made it line up with the performance chart.

I put in a new report that the 530D was high on drag and fuel mass is incorrect, which likely means the same is occuring for missiles of the same caliber. They also reduced the thrust on the R-27ER and reduced burntime to make sure it fits the same profile as before, while reducing fuel mass.

What matters is if the new drag coeff is in line with missiles of higher and lower caliber, and the answer is yes.

According to more authoritative sources it is 35g.


Yeah, I think this could be a mistake, that source says 35G’s maximum overload, this might be the dual plane value, with a 25G single plane value also commonly quoted.

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Missile is skid-to-turn only, maneuvering only on one axis at a time and due to limited differential deflection will have the same maneuverability in single or combined plane. The Moscow aviation institute indicates R-27R/ER is capable of 35G overloads to target and mentions nothing less.

The only sources that state an overload of less are those such as Janes from the 90s…
And mostly stems from the maximum target overload to intercept being approximately 8G’s (rule of 3x overload to intercept = 24G)… in reality this is maximum target overload for R-27R (not ER), and at longer ranges. The maximum maneuvering potential for the missile is not at maximum range, and this is reflected as it burns through energy in-game too. The R-27R at >50% of it’s maximum range launch at 5km will hardly be able to hit a target maneuvering at 7 or 8G.

The maximum overload of the missile and target is skewed further by an inaccurate or unreliable proximity fuse, something shared with earlier SARH based missiles and something the Russians have overcome on their R-77 and newer missiles.

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why would skid to turn prevent dual plane?

The missile is not capable of dual plane in the sense that the control surfaces cannot be deflected in such a way iirc. There is limited differential deflection capacity.

What would be the logical benefit of the new fin designs over the R-24s?

The new fin designs induce much more drag, and the idea that the Russians did so without any clear benefit doesn’t make any logical sense unless the R-24s aren’t actually 24G missiles.

Either R-27s are 25G and R-24s are much less than 24 (alternative theory), or the R-27s are 35G and R-24s are 24G (current situation).

Whatever the explanation is, it has to account for R-24s.

The R-24/R-27 have no roll control in combined plane, and in the event of control reversal due to fin AoA they need to have roll control. As such, it is roll stabilized and HAS to use two rudders for maneuvering, two for roll control with limited differential deflection angles. The missile has to maneuver in single plane.

American and Russian sources refer to the missiles maneuverability as single-plane rather than dual-plane.

European sources often refer to the missiles maneuverability as dual-plane.

Previously used source mentioned that the missiles maneuverability is 30g in a single plane.

35g mentioned in the new source is not dual plane maneuverability.


Then how come American sources stating the AIM-54 pulls 25G’s gets dismissed as “they’re stating dual plane” and the AIM-54 is instead gets a paltry 18G’s? Seems like a bit of a double standard.

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The AIM-54 may actually be 25G in single plane, or maneuvers constantly in combined plane. There is no primary source that states which… which is why it is currently limited in the game.

This is because the AIM-54 uses Bank-To-Turn (BTT), allowing it to utilize dual-plane maneuverability.


Riiiight, so, pardon my remark here, but its an intentional modelling decision thats advantageous for the R-27’s and disadvantageous for other missiles.

Thats super cool


I think he’s hinting at improvements to come SoonTM

It is incorrect to say that using only a single plane for the missile’s maneuverability is an advantageous for the R-27. This is because most missiles can only use a single plane.

AIM-9 uses rollerons, so it can’t roll, which means it can only use a single plane.

For the AIM-7, the roll channel commands it to prevent rolling. so same as above.

For the R.550, the rear tailplane will rotate for stabilization, but the forward canard for control will not. Since the forward canard will not rotate, dual plane cannot be used.

As with the examples above, the number of missiles that can actually use dual-plane maneuverability is fairly limited.

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Do we have a list of what ones can?

Its not wrong to say its advantageous to the R-27 though xD

Certain missiles are inherently having their maneuverability limited while others are not for no actual reason from the sounds of it. The R-27 is a missile that gains from this modelling decision as are some other missiles.

By definition, this modelling decision to only go to single plane limits of missiles is inherently advantageous to single plane only missiles by way of being disadvantageous to dual plane missiles. Theres no actual valid gameplay reason why dual plane missiles cant have their dual plane maneuvrability modelled in-game, it is SOLELY a design decision, just like the design decision of missile diamonds existing when missile motor burns, even on smokeless motors, is advantageous to low burn time motors despite things like massive base drag increases experienced by missiles when their motor burns out irl NOT being modelled in-game.

Regardless of how you choose to cut it, if a gameplay decision has inequitable results on missile/vehicle performance, there will inherently be certain weapons/vehicles ingame that win, and other that lose from that.

Pretending its not advantageous to the R-27ER (which has massive single plane maneuverability but doesn’t use dual plane) or other single plane only missiles, for things like AIM-54 to be modelled single plane only, with a MASSIVE 8G cut to its maneuverability (32% lower than it should be) is disingenuous.

There’s tons of these examples in WT, both throughout its history and even now. Things like late WW2 German tanks which had negative modifiers on their steel to “imitate poor steel quality”, Russian tank shells having higher chance to set things on fire/detonate fuel/ammo long ago, current spalling mechanics favoring Russian tanks, garbage NATO composite modelling, spotting mechanics, 2 seater jet mechanics, exhaust heat modelling, etc… All are inequitable modelling decisions which disproportionately favor one nation above the rest and are really becoming a sore point for players who play other nations in-game.

Its irrelevant how many vehicles/weapons are DIRECTLY affected by these modelling decisions negatively impacting them, as all adversary vehicles/weapons are POSITIVELY impacted by said decisions, and pretending that isn’t so is just outright lying.

These modelling decisions are also why I am EXTREMELY worried about the implementation of the R-77 in WT, as it is likely a rather poor missile in the specific circumstances of WT air combat (low altitude transonic or even subsonic launches, and only holds advantages at high supersonic launches over contemporary missiles, but with the current simplistic drag model being used, and more specifically gaijins track record, there is no reason for anyone to believe they would actually model this disadvantge.

It’s not, missiles that are limited to single plane maneuverability are done so because they can’t utilize combined plane outside of very specific moments wherein target is 45 degrees from control planes.

The missiles that use combined plane maneuverability all the time will do so in-game. There just isn’t enough evidence for AIM-54 yet.