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

[sudo_su1]

@MiG_23M

They’d remove it if it was classified - as the weight of the AMRAAM is STILL classified. Yet it wasn’t redacted because the actual weight isn’t listed.

https://www.navair.navy.mil/foia/sites/g/files/jejdrs566/files/document/[filename]/FINAL%20VERSION%20Thesis_An%20Outisider's%20View%20of%20the%20Phoenix%202021-010204_0.pdf

AR 380-5 Appendix G Security Classification Guide Preparation:

AR 380-5 Section 3-Performance and Capabilities

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                                      Classification Declassification or review 
Remarks
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31. Missile

    a. Altitude

     (1) Maximum                      C              DECL 10 Jun 92

     (2) Minimum                      U

    b. Range

     (1) Maximum                      S              OADR                       
""In excess of
                                                                                
10 km'' is
                                                                                
UNCLASSIFIED.

     (2) Minimum                      U

    c. Velocity                       C              OADR                       
See Note 9.

    d. Acceleration                   C              OADR                       
See Note 9.
    e. Maneuverability                S              DECL 10 Jun 92             
Downgrade to
                                                                                
CONFIDENTIAL
                                                                                
upon IOC.
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AR 380-5 Section 4-Specifications


(As  suggested in  DOD 5200.1-H,  this section  should address  the
characteristics  of  the   system  and  how  it  operates-not   its
capabilities or  level of performance, which  should be covered  in
Section 3.  For example,  for our imaginary  XXXXX Missile  System,
ranges, velocities,  and acceleration are  discussed in Section  3.
Details of rocket  motor functioning, though, are included in  this
section.)

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                                      Classification Declassification or review 
Remarks
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40. Rocket motor

    a. Size, weight, details of       U
    construction

    b. Fuel

     (1) Components of  Mixture       U

     (2) Proportion of  Components    C              DECL 3 May 93
    in Mixture

    c. Burn rate                      C              DECL 3 May 93

    d. Thrust Achieved                C              DECL 3 May 93              
Thrust, stated
                                                                                
alone, is UN-
                                                                                
CLASSIFIED un-
                                                                                
less it is the
                                                                                
maximum achieved
                                                                                
in flight.
                                                                                
Thrust in terms
                                                                                
of time from ig-
                                                                                
nition or launch
                                                                                
is CONFIDENTIAL.

    e. Fuel capacity, fuel load       U
    weight, and volume


(Physical  characteristics  such as  size,  weight,  power  output,
transportability, etc., should also be discussed here.)

[sudo_su1]

@MiG_23M

You still never answered;
Where does the additional weight come from?

@sudo_su1

@MiG_23M

It is important to understand where the additional mass is coming from.

LOL
It comes from the seeker and guidance section …

The missile was never 327 lb to begin with … That was just Hughes fantastical initial development estimate to get the contract …

They also said it will reach IOC by 1986 …
When in reality they had to redesign the seeker and guidance section because the electronic technology just wasn’t there to realize their fantastical claims …
And the IOC was pushed back to 1991 …

Spoiler

…

[Catnip007]

The extra weight wont change anything as the drag and thrust variables would be changed to continue matching the known engagement distances and time to targets.

[sudo_su1]

I never said there will be a drastic change.
But it will change the missile’s “behavior” … This could even be a buff …

[MiG_23M]

You still didn’t explain anything and used an old version of outsider’s view that is still highly redacted. Speak plainly. What are you trying to say?

All you did was repost a bunch of stuff that is irrelevant to the question.

[MiG_23M]

You don’t know what it would affect?

[sudo_su1]

Missile weights are usually not classified

Because you have to let a lot of people throughout your logistics chain and ground crew know about it anyways … Also not very useful information for the enemy without knowing the motor thrust.

[MiG_23M]

@sudo_su1

Missile weights are usually not classified

They were in the case of the AIM-54, and it is one of the parameters specified in the Outsider’s view document. That still does not answer any of my questions whatsoever or justify your absurd claims.

The ground crews generally carry a secret clearance, I do not see why the weight would need to be declassified for that. Even people loading and unloading cargo aircraft generally carry a secret clearance or are required to follow military law in regards to operational security measures and cannot release or discuss classified information.

[sudo_su1]

@MiG_23M

They were in the case of the AIM-54

Again, you fail to read:

“Weight information is unclassified” (And not even “declassified”, but “unclassified”)

[MiG_23M]

@sudo_su1

Again, you fail to read:

“Weight information is unclassified” (And not even “declassified”, but “unclassified”)

You failed to read, I stated “were”. Please don’t get sassy if it’s just going to result in further irony.
That is the point of the article. Such things were wishy washy and they needed to standardize methods of containing that information properly. Did you read the entire document?

[sudo_su1]

What matters is that the missile weights are usually unclassified.

So your theory that all the DoD official documents and studies that state the missile’s weight are “PSYOP” is wrong (if not laughable).

[MiG_23M]

@sudo_su1

What matters is that the missile weights are usually unclassified.

That isn’t the case.

@sudo_su1

So your theory that all the DoD official documents and studies that state the missile’s weight are “PSYOP” is wrong (if not laughable).

You continue to push that I said all the studies are psyop, I only stated that certain F-18 manuals were intentionally released with false information as a psyop.

[Gunjob]

Here is another spanner to be thrown in, AMRAAM is tuned to British data provided by the US and Hughes from the same documents that give the 327lb figure. So unless you’ve got more LSZ charts it’s not changing. As it’s tuned to that specific ~1992 version. Otherwise we’d be mixing different build standards with the wrong charts.

[sudo_su1]

@Gunjob

Here is another spanner to be thrown in, AMRAAM is tuned to British data provided by the US and Hughes from the same documents that give the 327lb figure. So unless you’ve got more LSZ charts it’s not changing. As it’s tuned to that specific ~1992 version. Otherwise we’d be mixing different build standards with the wrong charts

There are a few possibilities:

Spoiler

1- The charts are also calculated based on the initial development estimate and are unrealistic.

2- The charts are calculated based on updated information, but only that particular page with the weight which is mostly talking about AMRAAM project requirements and also says “327 lbs (designed)” is using information from another older document based on the initial development estimate.

3- The British AIM-120Bs are just built differently (see below).

@MiG_23M Seems like there was more (recent) changes than just seeker and guidance system.

In AMRAAM program’s SAR FY 1987 the “current estimate” was 335 lb with no “demonstrated performance”:

Spoiler

AMRAAM SAR FY 1988 was the first report to specify a “demonstrated performance” weight.
In AMRAAM SAR FY 1988 and SAR FY 1989 the “current estimate” was 335 lb with a “demonstrated performance” of 342 lb:

Spoiler

However, there was another change in current weight estimate in AMRAAM SAR FY 1990.
The whole “Performance Characteristics” section was redacted in SAR FY 1990 so we can’t see the weight estimates, but the reason for the change of weight estimates is not redacted, stating: “Missile weight increased due to a change in materials”:

Spoiler

Note that it’s erroneously included in the “Previous change explanations” section, even though the change was first made in AMRAAM SAR FY 1990 (this explanation nor any weight changes were present in the SAR FY 1989), so it should’ve been in the “Current Change Explanations” section.

The next year, in AMRAAM SAR FY 1991, the government employee doesn’t go overboard and doesn’t classify the whole “Performance Characteristics” section and leaves out the weight estimates. Here, compared to SAR FY 1988 & 1989, the “current estimate” for weight has changed from 335 to 345 lb, and the “demonstrated performance” has changed from 342 to 344 lb:

Spoiler

In AMRAAM SAR FY 1992 & 1993, again the nice lady working in the DoD redacts the whole “Performance Characteristics” section, so we can’t see the weight estimates (but we know there is no weight reduction, as the explanation for weight increase due to change in materials is still there, and there is no other weight change explanations to suggest a reduction):

Spoiler

But F-16 SAR FY 1993, which is also the first F-16 SAR to list a demonstrated performance for F-16C AMRAAM weight, lists “demonstrated performance” at 345 lb:

Spoiler

This would explain why the British manuals list AIM-120B at a lower weight compared to the weight listed for AIM-120A/B in the US aircraft manuals.

I.e. difference in the materials used, most likely to save cost. (US needed a lot more missiles than the British, and the program already had massive cost overruns)

This also explains the weight difference between the weight of AIM-120B in the F-16C manuals for the Hellenic Air Force (341 lb) and USN manuals (348 lb). Different materials.

[MiG_23M]

I don’t think “different materials” explains anything, only complicates the matter and the weight is still too much. More than 330 pounds is not realistic for AIM-120A.

[sudo_su1]

@Gunjob

Here is another spanner to be thrown in, AMRAAM is tuned to British data provided by the US and Hughes from the same documents that give the 327lb figure. So unless you’ve got more LSZ charts it’s not changing. As it’s tuned to that specific ~1992 version. Otherwise we’d be mixing different build standards with the wrong charts

I updated the report to reflect the new findings:

https://community.gaijin.net/issues/p/warthunder/i/8neWOIwbKGAr

Also solved the envelope issue:

9- I had previously made this report, but Gunjob had closed it citing a 1992 document from the UK which stated “Weight: 327 lbs (Designed)” for the AMRAAM:

https://community.gaijin.net/p/warthunder/i/c3Zavuod4L8o?comment=d8eGzGRgwYbuwZDta3qAk0Wg
https://imgur.com/a/pVWYf1M

Gunjob’s document does not apply to AIM-120A, because:
It’s from 1992. And it’s regarding AIM-120B as ordered by the UK military and produced to its requirements, which entered production in 1994.
This does not reflect AIM-120A as ordered by the US military and produced to its requirements.

However, since this UK document is used for adjustment of AMRAAM’s performance envelope in the game, the devs could keep the AIM-120B as is, and copy-paste all of its parameters for the modeling of AIM-120A, but only change the weight to 345 lb.
This would reflect the AIM-120A much better and reflect US military’s decision to produce a heavier less performant but cheaper AMRAAM (as compared to UK’s AIM-120B) for itself.

[sudo_su1]

Well, it was quite complicated in real life too.

I added some other interesting stuff to the report too:

[sudo_su1]

@Flame2512

Sea Harrier FA.2 manual lists AIM-120B as 331.9 lb / 150.5 kg. Just to add to the confusion.

Mystery solved?

[EL337GH0ST]

The US still used both AIM-120A and B and according to you one should be heavier and one lighter, at this point you’re just trying to intentionally nerf the US if you want the AIM-120A to be heavier while not having the B variant…but this is expected while looking at your other reports

[sudo_su1]

According to USN flight manuals both AIM-120A and AIM-120B weigh 348 lb.
So the US also used heavier materials for its AIM-120B …
Didn’t want to make it even more complicated.

@EL337GH0ST

at this point you’re just trying to intentionally nerf the US

LOL

I make reports to make things more accurate (also enjoy investigation).
Sometimes it’s a buff sometimes it’s a nerf.

Plus, I think making AIM-120A more accurate is actually good for the game right now, considering it outperforms all other missiles.

UK can get a pass since seems like they used the luxury material IRL and also their platforms are not as good so …