[RESOLVED] S400 40N6 Powered All the Way

[thewood1]

And the 9M82M on the late S-300 is also full power all the way. I am pretty sure there are others. So what exactly did you test to come to the conclusion that only the 40N6 was the only one showing this characteristic?

[Mickeys91]

How about the SA-5 it seems to also have unlimited fuel? is this WAD for a strategic AAW meant to shoot down AWACS/ELINT aicraft or is it missing the boost to coast model? from my understanding the rockets had 4 solid-fueled strap boosters able to hold up to 150 seconds but in the test I had I had one go for almost twice that distance (close to 4 minutes) with the entire time the missile was gaining speed to its near max range attempting to hit a B-52

[Gizzmoe]

So what exactly did you test to come to the conclusion that only the 40N6 was the only one showing this characteristic?

That wasn't my conclusion.

[thewood1]

"PAC-1/2/3 and S-300 for example use the new boost-coast model, the 40N6 and others don't."

What others?

[Gizzmoe]

"PAC-1/2/3 and S-300 for example use the new boost-coast model, the 40N6 and others don't."

What others?

Going by the infos it's SM-3, 9M82, PAC-2 GEM+, 40N6, and Mickeys91 mentioned the SA-5. There's probably more I guess.

[thewood1]

Can you post the scenarios where you tested those? I ran through a bunch but didn't some of those.

[Gizzmoe]

Can you post the scenarios where you tested those? I ran through a bunch but didn't some of those.

In case you haven't tested the S400 already, here's a scen:
https://www.matrixgames.com/forums/view ... 0&t=386768

I don't have the save of the PAC-2 test anymore. I haven't tested the SM-3 and 9M82, Dimitris mentioned that they don't use the boost-coast model.

Not all AAW missiles use the new boost-coast model; some missiles which are considered ABM-optimized deliberately retain the "powered all the way" assumption. This assumption is generally true for such missiles (other examples: SM-3, 9M82), as they tend to be highly overmuscled for their ABM priority.

[thewood1]

OK

[Gizzmoe]

Can you post the scenarios where you tested those? I ran through a bunch but didn't some of those.

Here is a test with the SA-5c.

[thewood1]

I ran some tests with the SA-5c and I'm not convinced there is an issue, or at least not the same issue. In real life, the missile itself is a very complex engine model and its basic controls (advanced for the mid-60s) only allow a couple different profiles to be used. Close range is a straight shot at the guide points. Long range was a more shallow lift and then keel over near target altitude. And it looks to me like its powered all the way with about 4 minutes of liquid fuel flight, on top of the solid fuel lift motors that run for about 8 sec.

[Gizzmoe]

And it looks to me like its powered all the way with about 4 minutes of liquid fuel flight, on top of the solid fuel lift motors that run for about 8 sec.

Do you know if that is close to how it would perform irl? It seems overpowered to me, but maybe I am totally wrong.

[thewood1]

I don't know from experience. But looking at the engineering specs and the control tech available in the late 50s to mid-60s it aligns with performance in the game. Taking into account that CMO doesn't simulate full PID or GRR control loops, its plausible. And frankly, plausible is mostly what you should expect with any PC game like this.

btw, I don't think its overpowered at all, regardless of motor characteristics. Its barely 50% against a non-maneuvering B-52 at 10km height. Against a maneuvering target, it would suck. The only overpowered aspect is that the complexity of the entire closed loop search, acquisition, and fire control system should be a big factor.

[Gizzmoe]

btw, I don't think its overpowered at all, regardless of motor characteristics. Its barely 50% against a non-maneuvering B-52 at 10km height. Against a maneuvering target, it would suck.

Yes, good point. I just checked the base PoH, it's 55%...

[thewood1]

This video does a great job of explaining the P method in PID thats used to control the missile tracking. At 7:00, the description of the trajectory aligns very well with CMO's modeling of the SA-5 and proportional control. It would explain why the missile is powered all the way. It will not overshoot the target except due to inertia. No lofting.

https://www.youtube.com/watch?v=aZn9qg0XbSg

It also explains why the SA-5 can't hit modern maneuvering targets that know its coming.

edit...noted the the missile is programed to fly higher than the planned interception point and dive down. But the thrust is constantly adjusted to limit G-loads for some basic maneuvering.

[Gizzmoe]

Thanks for the link, that was an interesting video. It was interesting to see that the boast-coast model wouldn't make much sense there. It has a long burn-time and could surely coast quite a distance without propulsion, but the SA-5 has a max flight-time of 250 seconds, then the battery runs out (mentioned at 10:35 in the video), so...

edit...noted the the missile is programed to fly higher than the planned interception point and dive down.

Yes, and as you said, CMO doesn't model that for the SA-5 it seems. That seems to have no negative impact though in-game, the SA-5 looks like it is a plausible approximation of how it would behave irl after watching the video.

[bsq]

I ran some tests with the SA-5c and I'm not convinced there is an issue, or at least not the same issue. In real life, the missile itself is a very complex engine model and its basic controls (advanced for the mid-60s) only allow a couple different profiles to be used. Close range is a straight shot at the guide points. Long range was a more shallow lift and then keel over near target altitude. And it looks to me like its powered all the way with about 4 minutes of liquid fuel flight, on top of the solid fuel lift motors that run for about 8 sec.

Its close, some of the numbers in various sources are not quite right. As for engine, its very old in theory, using the same fuel/oxidiser mix as the German V-2. (Tonka with RFNA). Indeed in the video you can see a puff of rust coloured smoke in the trail, indicative of the RFNA flow starting immediately prior to the sustainer firing up. The mode of flight has to be set before launch , it must lock before launch and, if it loses lock, after several seconds it will self destruct. 250 seconds TOF is about right, the final act of the onboard electrical system as it is about to lose power is to tell the missile to go 'bang', rogue telegraph poles are the last thing you want.

So this is not powered all the way unless it is on a short range profile.

[Gizzmoe]

As for engine, its very old in theory, using the same fuel/oxidiser mix as the German V-2. (Tonka with RFNA). Indeed in the video you can see a puff of rust coloured smoke in the trail, indicative of the RFNA flow starting immediately prior to the sustainer firing up.

Hehe, thanks, I was actually wondering what that brown puff was

[thewood1]

Actually it might be powered all the way, just not full power all the way. The docs state that there is actually a throttle-like control on the oxidizing mixer that operates depending on profile and target control feedback loop. So it might be powered all the way, but with a throttle for lower power at long range. That would make engineering sense at least. Its one of the advantages of the liquid system.

[Mickeys91]

In the end I do hope the devs keep improving on rocket/missile physics as I its a very interesting part of warfare. The boost to coast update was a huge game changer so devs are going in right direction.

[LetMePickThat]

The only place you'll find 40N6 in this case is in the C ring or St Petersburg. where ABMs should reside. The rest will just be 21's with 48N6 (all flavours) and 9M96 all flavours.

Not really, the 40N6 is primarily intended as a HVT buster, meant to go after tankers, AWACS, JSTARS and other assets that:
1 - cannot outrun it,
2 - can have a significant impact on the battlefield even from far away and need to be kept at bay.

There's no point in having a BMD-optimized missile with a 400+km range if you can't handle a BM engagement that far away, and the S-400's radars (96L6/E, 91N6/E, 92N6E) are woefully inadequate for that. Look for instance at the S-300VM/V4: both the 9S19ME/M2 and the 9S32M/ME have much higher power outputs than their S-400 counterparts. ABM on the 400 is done at shorter range, primarily with the 48N6E2/DM (E3) and the 9M96E/E2. This is also visible in the typical S-400 battery composition, where usually only a single TEL is equipped with 40N6s whereas BMD usually requires a significant volume of fire.

As for the subject of BMD not using the burn-coast model, I think that it is a reasonable assumption for short range and exoatmospheric systems, because those will either intercept very shortly after ECO (53T6) or fly for a significant portion of their flight outside of meaningful atmosphere. For dual-use rounds (e.g PAC-2, 48N6, Aster 30, David's Sling...), the boost-coast would IMHO provide better results. The 40N6 should definitely use the boost-coast model as well, since it isn't meant primarily for BMD. I also doubt that the solid fuel budget on the missile would allow for continuous thrust all the way to max range.

Then, there's also the question of multi-stage systems and how those could fit in either the continous-power or the boost-coast model...