That seems awfully low? The SLM is more than 60 kg heavier than the standard IRIS-T (155 kg vs 88 kg) so it having only 25 kg more fuel is kinda… strange? Especially as the rocket motor is the only thing that is bigger (longer, larger diameter) for the SLM while everything else (guidance, warhead) has the same size as the standard IRIS-T.
same for me, i just wanted to see if it is a stratistical outlier
but it is weird that the IRIS-T SLS and SLM have a different impulse per kg of propelant, because they propabaly use the same propelant
it seems like you might have a wrong weight for the IRIS-T SLM, i found 110kg as an weight, gotta check the sources real quick tho
Strange. Guessing from the size (two third with much larger diameter and therefore volume and half a meter more length) it should weight much more than only 22 kg more than the standard IRIS-T. Even if the propellant would be exceptionally light with 2-3 g/cm³.
Actually, now that I look at it, I think it’s just Isp what I am noting down. Just without dividing by the gravitational acceleration (say roughly 10), not completely sure if I can just take just the fuel and not the total engine weight though.
I know at least that an Isp of 150-250 is fairly realistic, 400 would be really high on the other hand, if it does use solid fuel.
The best source we have for weight does state weight between 140-150kg, and that source is a polish defense book that featured some production details, the first SLM missiles were only 152mm so those might have weighed 110kg but the ones currently in production and we have in WT are 180mm so heavier as well.
Jecka is currently ordering that book, i hope gaijin will consider it even if it’s a polish source.
And it has Mach 3 speed as well, but again we’ll have to see if it’s a good enough source for gaijin.
Edit: the website where he found it and the books mentioned in the sources
Could be because of the different burn profiles. Different mixtures of propellant in each stage (four for the standard IRIS-T, two for the SLM), different grain geometry and so on.
but that much of a difference seems weird
1744Ns/kg for the SLS vs 2350Ns/kg for the SLM
Not really as the IRIS-Ts four stage burn profile is fairly complex with a focus on maneuverability (especially at the moment of launch) to hit targets maneuvering targets in a 360° sphere nearby while the SLM seems to be optimized for extremly strong boost from the start and high speed sustain to hit targets way further out and only in a 180° half-sphere, so only 90° course corrections in a fairly big radius are needed. One being air- and the other ground-launched is also a factor.
Many such cases of Gaijin moving the line for Russian vehicles and armaments while saying ‘We believe this is wrong’ or ‘We believe this is a clear marketing lie’
Ukrainian press releases have made some public statements about the IRIS-T SLM speeds, and those were rejected for not being reliable, yes, the country that’s operating IRIS-T right now is not a reliable source lmao.
It’s not some occult knowledge that it can achieve Mach 3, it’s probably going to be shut down under the same pretext or that “it does not come from the country of origin” which was the last excuse they used when we tried foreign sources (an excuse the devs have never used before).
It seems that devs are under some strict rules for rejecting any source that isn’t from Diehl themselves, so that buffs cannot be applied, I’m not very hopeful, but we have yet to see.
This is actually a REALLY interesting theory, cuz it would actually explain quite a bit.
According to this paper from 2018, composite rocket fuel with an AL-Li additive exhibit increased performance and, interestingly, significantly reduced HCl production:
The increased performance of the motor is also supported by this study from 2023, along with it stating that Al-Li additives also reduce the size of the condensed combustion product(the metal particles in the exhaust)(CCP), which may also effect how visible the smoke trail is:
Spoiler
Which takes us to this ol’ piece of info regarding missile smoke trails:
Spoiler
Propellants with an Al-Li additive would be characterized as “metal fuel”, which would suggest it to still have a smoke trail due to the metal particles in the exhaust gases, this is why smokeless propellants eliminated the metal portion of the propellant despite the reduction in thrust, but in the case of an Al-Li propellant, it seems they chose to reduce both the HCl portion along with the CCP size of the contrail, which would explain why the IRIS-T seems to have more smoke than something like the AIM-9X, which appears to have gone all in on the “no smoke” idea, but less smoke than something like a Pantsir missile:
Picked these pics cuz they were all (except 1 of the 9X ones) in similar environments (deserts), which is important to match since temperature and humidity play a role in formation of smoke/contrail:
9X:

IRIS-T SLM:
Pantsir:
So an AL-Li composite propellant might actually explain 3 things; the high range, the reduced smoke, and the flames colour.
All that being said though, Id have to see proof that the rocket motor is in fact using a propellant with lithium inside. They definitely do exist commercially, such as ALITEC produced by the US company “Anduril”, claiming a 40% improvement in range:
But afaik, NAMMO Raufoss doesn’t openly state they have any lithium propellants, so at the end of the day, we’re speculating.
Lithium is also very light, 0.534g/cm^2, which could explain the marginal increase in weight despite the substantial increase in size over the baseline IRIS-T.
Fun little bit of coincidence; if you multiply the 148050Ns of impulse by the 40% improved range claimed by Anduril for ALITEC, you end up with 207270Ns of impulse and 3290N*s/kg, which clears the “200kN+” statement, granted I know range isnt 1:1 proportional to thrust though. I just think its an interesting coincidence👀
Of note, the Ukrainians are not only “a country” operating the IRIS-T SLM, they are by far the country operating the most IRIS-T SLM’s, along with being the country with the most combat experience with the IRIS-T SLM…
They rejected sources from Diehl themselves as well, so I wouldnt put any faith in them accepting any source that would buff the missile in any way.
They’re clearly on strict rules to refuse any and all possible buffs to the IRIS-T missile family in general…😐
it feels like what ever we do they wont change it.
It might be time for another [REDACTED]
Okay this is just false, The Effective range of the Pantsir is like 12 to 13km at most in game. Anyone hit at 18km is a cooperative target (ergo flying straight)
At 12.5km, the 95Ya6 is still going faster that the top speed of all other missiles in this sheet.
At 15km, its still going faster than all the other missiles on the sheet are going at 7.5km (barring the SLM with its slow ramp up in speed).
If the Pantsir’s effective range is only “12-13km”, all the new SAM systems are dead in the water.
Ergo a straight line, it bleeds a lot of speed in any kind of maneuver (as is the case of any missile).
The thing about the pantsir, although not modeled in game (3d wise anyways) is that the booster section get separated (afaik) after it uses up the 2.5s burn time and it essentially becomes a proxy dart for most of its flight
What are your sources that state that capability?
Russian mains always argue that the Pantsir is in-effective past 12km and it is just not true. I have flown extensively against the Pantsir and other top tier spaa systems and while the Pantsir may not have the same maneuverability throughout it’s entire flight, it is still easily very much a threat to wayyyyy further than 12 km.
From the situation of the test suit, yes, all newly added top-level air defense units cannot achieve or exceed the performance of the Panstir, which means that the next version of the top-level land warfare still belongs to the KH38MT. Furthermore, if these air defense systems only have usable performance at close range, can it be considered that the introduction of these air defense systems is aimed at weakening the Eurofighter, rather than the Su-30 or Su-34. I have to start doubting whether the imbalance of air ground confrontation in the next version will further intensify