The AIM-120 'AMRAAM' - History, Design, Performance & Discussion

One step I did miss from the sequence.

Accelerate.

Along with the missile lofting itself, it also uses a lot of energy getting up to and past Mach 1.

Lock
Accelerate past M1.0
Wait for Launch cue
Pitch up
Launch
Manoeuvre to maximum radar gimbal and maintain lock until Pitbull.

Accelerating is not as important as climbing. You could launch from mach 1.2 on the deck (which takes time to accelerate), or begin climbing to a higher altitude and then launching from 0.9 mach. The launch from 0.9 mach at a higher altitude will almost always hit the target first.

Another example, you have two fighters at 0.9 mach (they accelerated to this speed from the runway, so are at sea level). Both decide to climb to 10km. One launches the missile sooner from 0.9 mach. The other takes the additional 30 to 60s accelerating before launching at ~1.5 mach.

The one who accelerated is now closer to the target, his missile reaches the target later, and he has to defend against an enemy missile that he is now potentially within the minimum abort range for.

Anyhow, climbing is more important than accelerating unless there is time to accelerate before coming within the minimum abort range of the enemy ordnance.

Looks like the AMRAAM is still smoky in the trailer:

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Only the ground launches video is relevant

AMRAAM is low smoke

How they do smokeless in game isn’t accurate to real life

I’ve already explained this a million times for pro-russians players that pull out youtube videos of NATO missile launches to “prove” they arent low smoke/smokeless.

AMBIANT TEMPERATURE AND HUMIDITY IMPACTS SMOKE PRODUCTION FROM MISSILES IRL

What you’re seeing in your videos is water vapour formation from the exhaust, NOT smoke as typically seen from less advanced propellants like those used by older missiles, or russian ones.

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Well, it affects ALL MISSILE, not just for NATO. And if you already turn off the smokiness, then EVERYONE. 1.5 the conditions under which a NATO missile does not smoke is not a reason to make them smokeless

It should be if it can be expected to launch under said conditions, theoretically it wouldn’t be impossible to actually model how this changes since the chemistry is pretty well understood and Ambient air pressure and temperature is already modeled, the only thing missing for an accurate model is modeling humidity and the dew point of ambient air, which for simplification purposes could be generated from the existing temperature and pressure models.

You do understand that they probably use different propellants right? Do we even know if Russians use HTPB in place of CTPB or other solid fuels for their relevant missiles? Pretty sure its well understood that the relevant low smoke US motors all use HTPB based compositions.

The low aluminum (smoke) compositions ( historically they tended to be HTPB based) give up some portion of their performance (more modern compositions can recover some of the lost performance) in exchange adjusting the conditions under which the equilibrium reverses and so trends into preferring to produce 2Al3O (Aluminum (III) Oxide; a fine white powder) as a byproduct instead of Al2O (Aluminum (I) Oxide; a colorless gas), the problem was the the Carbon in CTPB compositions based fuels works as a catalyst that promotes the production of Al3O2.

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The old video is most likely the first version of AMRAAM that smoked.What kind of fuel composition in Russian rockets should be studied patents may have something written there

Its probably just a bad day where the the ambient temperature and absolute humidity at the point of motor firing are sufficient to noticeably influence the equilibrium of the reaction(s) taking place.

The AMRAAM has two motors the The “High Performance Rocket Motor
which uses a single, reduced-smoke HTPB propellant in a boost-sustain configuration.

and the “+5 Motor” Rocket motor which is an enhanced version with an additional 5 inches of propellant.
(It doesn’t specifically list a change in propellant composition) Though it requires the use of the Shortened Guidance section to maintain overall length of the missile, this came into effect with the introduction of the AIM-120C-5. The lengthened motor can be a useful distinguishing feature, for deducing if the missile is an Early -C or Late C/D variant.

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Is there a discernable difference between the 120A and 120B? I remember there being a range difference, but it might’ve been something I made up in my own head, since if the 120B had a better seeker (and so can detect targets at further ranges), it would be able to be deadly at further ranges than the 120A.

120B is easier to make ( should be cheaper in repair cost)

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This BBCRF guy loves to complain about anything Nato. Its kinda annoying

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That signs of Russian main alright

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The propellant composition of the AMRAAM is already well known because orbital ATK has made such info public. It’s how DCS got such accurate motor and thrust data for the AIM-120C-5. The study for the AIM-120A performance has estimates that were too high and had wrong data for booster.

We now also have good data for the AIM-120A/B thanks to the Korean study in my OP, which is what is used for in-game.

Also, all the nonsense off topic stuff about ‘russian mains’ can stop. BBCRF doesn’t even have top tier Russia air rn afaik. Y’all can DM about that stuff or I’ll need to get staff involved.

How is this off topic? Y’all crazy

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Question about the aim120 What happens if it loses the target in the notch at say 7nm?

Does the missle search the potential flight path to the intercept point or does the seeker cone immediately jump to the intercept point?

I would presume it scans and tries different methods of acquiring the target