What AIM-120C do we have?

[Northstar98]

I'm not sure exactly when it changed, but I noticed that the AIM-120C no longer is listed as "AIM-120C-5" (which it definitely once was - see this screenshot, taken from this post from September 2022) but just "AIM-120C".

So, a couple of questions:

1. What AIM-120C variant do we actually have in DCS? Or at least, what is it supposed to be? AIM-120C-5 is from the early-ish 2000s and so is appropriate for the F-15C, F-15E, F-16CM and F/A-18C. Was the C-5 designation a mistake and that we actually had the base AIM-120C variant from the mid 1990s?
2. If it is still supposed to be an AIM-120C-5, why the name change?

[ACS_Dev]

On 5/16/2024 at 4:34 PM, Northstar98 said:

I'm not sure exactly when it changed, but I noticed that the AIM-120C no longer is listed as "AIM-120C-5" (which it definitely once was - see this screenshot , taken from this post from September 2022) but just "AIM-120C".

So, a couple of questions:

1. What AIM-120C variant do we actually have in DCS? Or at least, what is it supposed to be? AIM-120C-5 is from the early-ish 2000s and so is appropriate for the F-15C, F-15E, F-16CM and F/A-18C. Was the C-5 designation a mistake and that we actually had the base AIM-120C variant from the mid 1990s?
2. If it is still supposed to be an AIM-120C-5, why the name change?

Hi NorthStar,

I recently posted a lengthy thread on AIM-120C sub-variants that ED is now investigating. I'd say it's worth the read if you want to know the differences between the variants and their acquisition history within our module's timeframes.

Assuming ED is modeling their AMRAAMS accurately:
-We must have the AIM-120C-3 or better because the wings are clipped
-We must have the AIM-120C-5 or better because of the lengthened rocket motor.

A look at the modelviewer and the two missiles suggests that ED chose to model an AIM-120C-3 or AIM-120C-4, not the C-5 (Either that or the AIM-120B is incorrectly modeled), However the guidance section on the AIM-120C is marked as being a WGU-41 of the AIM-120B family. Until today I assumed that the lengthened rocket motor was present; a comparison of the AIM-120B and C rocket motor modules in-game revealed their length to be the same. Also I believe you on the C being named the C-5, however a review of my datamines as far back as last June showed it as just the C. Further, the modelviewer shows the missile model not being updated since I installed it in late December of last year.

Historically ED has done things like rename L16 in the F-16's DED to TNDL in order to skirt copyright or something similar, this might be the case but I kind of doubt it.

As I claim in the linked thread, certain modules, in particular the Viper, should have the AIM-120C-6 at the very minimum, likely also the AIM-120C-7. I proved in the linked thread that the USAF had taken delivery of hundreds of both missiles by 2007. I also argued that our viper would carry them into battle given the missile's test history and overlap with the OFP upgrade program as well as this particular viper variant being instrumental in SEAD operations. The question of the F-15 and F-18 is more complicated, again I'd encourage you to refer to my post.

So in conclusion, I came here to tell you that ED modeled the C-5 and the model reflects it but now I am quite confused myself.

Edited July 21, 2024 by ACS_Dev
Incorrect assumption of overall C-5 missile length change

[Northstar98]

Okay, this is all quite confusing.

2 hours ago, ACS_Dev said:

I recently posted a lengthy thread on AIM-120C sub-variants that ED is now investigating. I'd say it's worth the read if you want to know the differences between the variants and their acquisition history within our module's timeframes.

I did read your post, I really appreciate it when users do deep dives on topics such as this, so thank you very much!

2 hours ago, ACS_Dev said:

A look at the modelviewer and the two missiles suggests that ED chose to model an AIM-120C-3 or AIM-120C-4, not the C-5 (Either that or the AIM-120B is incorrectly modeled), However the guidance section on the AIM-120C is marked as being a WGU-41 of the AIM-120B family. Until today I assumed that the lengthened rocket motor was present; a comparison of the AIM-120B and C models in-game revealed their length to be the same.

The only thing I'd watch out for here is that ED have historically called something one thing, but the model/textures depict something else. That's not to say any of your conclusions and reasoning are wrong of course, but it might be something to consider.

Just to name some examples:

Spoiler

• AN/MPQ-46 HPIR from I-HAWK PIP Phase I actually has the model of a HEOS-equipped AN/MPQ-57 HPIR from a German I-HAWK PIP Phase II (HEOS however isn't actually modelled as a sensor in DCS).
• V-755 (20D) missile from our S-75V/M Volkhov has 11DU (i.e. V-750VM) written on the side of it. Its model and textures are also incorrect for a V-755/20D series missile.
• Every truck with Ural-375 in its name has the model of a Ural-4320.
• The Chieftain Mk 3 has the model of a tank that isn't a Mk 3 (considering it appears to have Totem Pole and Dark Morn/Sundance upgrades. If it's supposed to be based on a Mk 3, that makes it a Mk 7/L at least).
• The Type VIIC U-Boat U-flak has the model of a 1944/45 Type VIIC or Type VIIC/41, not a U-Flak.
• 9M39 is mistakenly called Igla-S.
• The SS-N-2 Silkworm is actually an HY-2 (CSSC-3 Seersucker) and has HY-2 written on the side of it. In this case it's particularly messy because not only is the NATO designation and reporting name inaccurate to what's depicted, they also don't even match each other (SS-N-2 is for the ship-fired P-15 missile and Silkworm is for the HY-1 missile).

This also isn't counting that the new naming scheme (which IIRC was introduced in 2.7, though it might have been later) in made some other names more ambiguous, despite a significant increase in length (Kh-22N had the N dropped, the 9K37M1 Buk-M1 has had the -M1 dropped).

I took a look at the AIM-120B model and its guidance section is marked WGU-16/B, which according to the same source you linked, belongs to the AIM-120A (and the WGU-16/B marking is present on the guidance section of the AIM-120A model).

2 hours ago, ACS_Dev said:

Also I believe you on the C being named the C-5, however a review of my datamines as far back as last June showed it as just the C. Further, the modelviewer shows the missile model not being updated since I installed it in late December of last year.

It was at least named C-5 a year and a half ago or so - the linked screenshot and the linked post proves that. I'm not sure which update changed it to just C.

2 hours ago, ACS_Dev said:

Historically ED has done things like rename L16 in the F-16's DED to TNDL in order to skirt copyright or something similar, this might be the case but I kind of doubt it.

I don't think this is the case. The missile is still referred to as AIM-120 and AMRAAM, it would strike me as very odd if its was the variant name alone that was problematic. The Sidewinders are manufactured by Raytheon (same manufacturer as the AIM-120) and at least the P series have their variant names (P, P-3, P-5).

Edited May 17, 2024 by Northstar98
Added comments on AIM-120A and AIM-120B models

[ACS_Dev]

9 hours ago, Northstar98 said:

It was at least named C-5 a year and a half ago or so - the linked screenshot and the linked post proves that. I'm not sure which update changed it to just C.

Apologies, I worded that poorly. It is clear that it used to be called the C-5, I wasn't trying to claim otherwise. The 'however' was because I thought it might originally have been done quite recently, instead I looked back into the datamines and realized it was actually a pretty old change.

9 hours ago, Northstar98 said:

I don't think this is the case. The missile is still referred to as AIM-120 and AMRAAM, it would strike me as very odd if its was the variant name alone that was problematic. The Sidewinders are manufactured by Raytheon (same manufacturer as the AIM-120) and at least the P series have their variant names (P, P-3, P-5).

Yeah I don't think so either. It was one of few possible explanations for the change. To be frank, I typed this up last night after having recently posted the thread and in my tired state I contemplated the idea that ED intentionally made the naming more ambiguous because they didn't want to get into modeling sub-variants. However, after looking back I realized this was not related to my post because it was more than a year older. Maybe they don't but it wasn't a recent development and certainly wasn't because of anything I wrote.

The missile length thing is probably worthy of a bug report, I will submit one at some point when I figure out whether it's the AIM-120B being too long or the AIM-120C-ish one being too short or neither (which would be even weirder)

[Northstar98]

22 minutes ago, ACS_Dev said:

Apologies, I worded that poorly. It is clear that it used to be called the C-5, I wasn't trying to claim otherwise.

All good, no problem

22 minutes ago, ACS_Dev said:

The 'however' was because I thought it might originally have been done quite recently, instead I looked back into the datamines and realized it was actually a pretty old change.

Ah, I see.

Shame on me I guess for noticing it so late  I only noticed probably a few weeks ago at most and promptly forgot all about it.

22 minutes ago, ACS_Dev said:

It was one of few possible explanations for the change.

I mean, I'm stumped for a reason.

There's certainly names that are longer, in some cases a lot longer so it wasn't done to make the naming scheme more concise. Mind you, the new naming scheme (well I say new, it's several years old at this point) did the exact opposite, instead making names longer while making them more ambiguous.

It would be nice to get an official answer though to clear this up.

22 minutes ago, ACS_Dev said:

The missile length thing is probably worthy of a bug report, I will submit one at some point when I figure out whether it's the AIM-120B being too long or the AIM-120C-ish one being too short or neither (which would be even weirder)

Yeah, I can agree with that. lf you do it might be worth mentioning the incorrect markings on the guidance section (applies to both AIM-120B and AIM-120C) too.

Edited May 17, 2024 by Northstar98

[DCS FIGHTER PILOT]

On 5/17/2024 at 12:57 PM, ACS_Dev said:

The missile length thing is probably worthy of a bug report, I will submit one at some point when I figure out whether it's the AIM-120B being too long or the AIM-120C-ish one being too short or neither (which would be even weirder)

Let me throw in another (possible) monkey wrench. After many tests, I have concluded that the AIM-120B's rocket motor burns longer than the AIM-120C's as of the Open Beta Update on 7/11/2024. It looks like the B's rocket motor uses boost and sustain whiles the C's uses boost only. Perhaps this was already known and is correct. 

Edited July 12, 2024 by DCS FIGHTER PILOT

[ACS_Dev]

11 minutes ago, DCS FIGHTER PILOT said:

Let me throw in another (possible) monkey wrench. After many tests, I have concluded that the AIM-120B's rocket motor burns longer than the AIM-120C's as of the Open Beta Update on 7/11/2024. It looks like the B's rocket motor uses boost and sustain whiles the C's uses boost only. Does this even make sense? 

 

 

The C, when launched by an AI, had a total motor burn time of about 6.5 seconds, seemingly starting the moment it left the rail.

The B also burned right off the rail with a total motor burn time of around 7.09 seconds.

I watched using the FPS menu for time logging and 1/8 speed for precision.

Looks like you are correct.

I don't understand how this is possible.

[DCS FIGHTER PILOT]

1 hour ago, ACS_Dev said:

 

The C, when launched by an AI, had a total motor burn time of about 6.5 seconds, seemingly starting the moment it left the rail.

The B also burned right off the rail with a total motor burn time of around 7.09 seconds.

I watched using the FPS menu for time logging and 1/8 speed for precision.

Looks like you are correct.

I don't understand how this is possible.

I think I MIGHT understand what is going on. As I mentioned, the AIM-120B is using a boost and sustain motor. Due to this, it burns a bit longer than the C but is not as fast. The C on the other hand uses a boost only motor which causes the motor to burn out sooner but gives it a higher top speed. If I am not mistaken (and correct me if I am wrong), it was not until the C5 iteration where the rocket motor was lengthened. If this is the case, then we indeed DO NOT have a C5 but one of the older variants. If ED does truly model the C5, it should be a bit faster than both due to the larger motor. 

Edited July 12, 2024 by DCS FIGHTER PILOT

[ACS_Dev]

10 hours ago, DCS FIGHTER PILOT said:

I think I MIGHT understand what is going on. As I mentioned, the AIM-120B is using a boost and sustain motor. Due to this, it burns a bit longer than the C but is not as fast. The C on the other hand uses a boost only motor which causes the motor to burn out sooner but gives it a higher top speed. If I am not mistaken (and correct me if I am wrong), it was not until the C5 iteration where the rocket motor was lengthened. If this is the case, then we indeed DO NOT have a C5 but one of the older variants. If ED does truly model the C5, it should be a bit faster than both due to the larger motor. 

 

You are correct, the C-5 lengthened the motor. It would be a travesty if we didn't have the C-5. I have already proven that we should have access to the C-6 at the very least, almost certainly the C-7 as well. According to the budgeting documents (I have probably read them more times than most of the people they were meant for at this point), the C-5 was supposed to start deliveries in FY00. So the F-16's AMRAAM would be the better part of a decade old. The C-4 was introduced in FY99...

They did tag my thread as 'investigating' a week ago, so there is that.

[ACS_Dev]

Ok I made a mistake in my research by assuming that the AIM-120C-5 lengthened the overall missile. I realized this today while reviewing the 2004 USAF Weapons File.

"Rocket motor PN G672798-1 is an enhanced verision (sic) with additional 5 inches of propellant. It is commonly referred to as the +5 rocket motor. The control section consists of control electronics, actuator batteries, and four independently controlled servoactuators. Control section PN G725818 is a shortened (by 5 inches) version to be used with the +5 rocket motor." USAF Weapons File (Distribution A) 2003 P.16

So they lengthened the rocket motor but they likewise shortened the control section. The missile thus stays the same length. The control section is the rearmost module and houses the rotating fins. The 3D model's control section module is not visibly shortened. My point stands, just not as I originally thought.

It is worth noting that the same weapons file also states that the C-4 received an upgraded warhead. The AIM-120B and C in DCS have identical warheads in-game.

The files from the latest patch are included below.

AIM_120.lua
AIM_120C.lua

Edited July 18, 2024 by ACS_Dev