[WAD+TWEAK] S400 cant hit evading targets.. (post patch)

[SchDerGrosse]

Soo I was editing WRA templates for a scenario as per thewood1 suggested and got to to the growler missile.

After reviewing its statistics in the DBA I immediately knew that it will have problems as it has only 26 seconds of fuel.

Did a quick test and I was right.

The S400 battery is practically useless now and can only hit evading fighter jets from point blank.

Go and take a look for yourself. (just hit the play button and let the scenario play out).

Either I am screwing something up in which case I apologize, if not then jesus h christ i am so pissed by the new missile mechanics and the fact that it seems that noone cared to test them.

[blu3s]

If you have data to support another number please open a ticket on the database github.

For another post to complain about how missiles work in reality there are already a few threads open.It is becoming quite annoying

[SchDerGrosse]

For another post to complain about how missiles work in reality there are already a few threads open.It is becoming quite annoying

Just as annoying that I cannot play the game properly for which I have paid EUR 200+ for.

[thewood1]

There is something weird happening with SAMs in particular. I had noticed a couple updates ago and have only spent the time today to see if I could document it. It seems that as the target gets closer, the SAMs intercept energy gets lower and lower until the target is close enough to have almost a direct shot. In the example posted in this thread. It takes over 20 missiles at 75% firing range. I have no idea what cause this or how it should work IRL. Maybe someone can explain it.

First set of shots and the SAM is at 750 knots and 137 nm from launch.

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The next series of shots are the follow on from misses. Note that the SAM is between 700-800 nm every time it starts the tail chase as the travel distance for the SAM shrinks continuously. My common sense way of looking at this is that as you get closer to the launching point, the missile should have a little more energy each time. I think this might only happening non-direct/boost coast shots. Just start the OP's scenario and explain to me how an S-400 can fire almost 40 missiles before it kills the target at 30 nm.

[blu3s]

Thanks thewood for the clarification it seems an issue with the missile in particular. It will be investigated.

[thewood1]

I suspect something is going on with all boost coast missiles. I see similar, but harder to capture issues with other missiles that climb and dive.

[Edmon]

Either I am screwing something up in which case I apologize, if not then jesus h christ i am so pissed by the new missile mechanics and the fact that it seems that noone cared to test them.

Hey there,

I can assure you that all updates are very thoroughly tested, so we'd perfer it if you didn't imply that we don't care, because we very genuinely do and we wouldn't be here in the forums looking at this kind of feedback if we didn't.

This issue has been added to our tracker, we'll update everyone on this in due course.

Thanks,
Edmon

[Dimitris]

Finally had a chance to take a look at this.

[Dimitris]

First, a number of trajectory graphs by blu3s specifically for the 40N6 (warning, large graphic):



I had them checked out by someone who works on SAMs for a living, and he didn't find anything grossly/obviously wrong in the trajectory logics.

[thewood1]

Not withstanding your graphs...

So if the three/four main variables are range, altitude, speed, and maybe energy, at least two should vary in different interception scenarios. What I showed in-game is the following:

• Speed at intercept is almost the same (between 700-800 knots)

• Altitude at intercept is almost the same (between 40k ft and 42k ft)

• Range at intercept is the big variable (137, 127, 97, 87 nm)

• Energy left in the missile is basically the same at intercept point because they all exhaust rocket fuel early and about the same time, along with similar altitude.

So that means three key parameters are basically the same and only range is different. I only have captured range not time. I have to assume I am missing a key variable at the intercept point.

edit...to be more blunt

My supposition/worry is that no matter the range, the SAM's endpoint speed is pre-determined and other parameters are adjusted to match that. It is a wild-ass guess with out much data, minimal scientific foundation, but with a little observational experience.

[Dimitris]

I was actually discussing this earlier today with blu3s.

The key thing to remember is that: "getting close to the target" = "finally coming down to the target's altitude, where drag without thrust is a bitch".

Lofting missiles do indeed accelerate a lot after their loft "hump", thanks to gravity, but as they dive towards the lower atmosphere they are effectively "aerobraking" themselves (same reason that RVs of ballistic missiles sharply decelerate as they come down to their targets) and they reach their terminal velocity (ie. drag matches weight force), which gets progressively lower as their current altitude is reduced.

Because of the loft trajectory, this sharp braking happens mostly regardless of horizontal distance: In shorter-range shots there is certainly more residual energy at the beginning of the dive, but by the time the missile reaches down to the target the drag-braking has become the dominant force.

There is a significant point of variance at this point: Whether the target is oncoming or receding. In the latter case, the missile is forced at a run-down chase (or drag race, if you will) at roughly the same altitude as the target, which flatly wrecks its last energy reserves (look at the graphs above and note how the missile speed just craters as it bottoms-out to chase the target). If OTOH it's a head-on engagement the energy state is better.

This BTW is why aircraft tend to include a dive in their kinematic evasion routine (together with the axiom of "put the threat in your 6 and RUN LIKE HELL"), and why the split-S is a classic evasion tactic: Weight aside, an aircraft has built-in thrust with which to partially reclaim the energy lost due to the increased drag; the incoming missile only has the drag affecting it.

There are two other important factors to consider here: WRA firing range and the target aircraft's acceleration. I'll get into those in more detail tomorrow.

[thewood1]

I'll have to take your word for it until I can wrap my head around it.

[Dimitris]

I'll have to take your word for it until I can wrap my head around it.

I do realize parts of this can be counter-intuitive, because they collide with our intrinsic understanding of energy retention and speed-vs-altitude. Here's something that will hopefully make it clearer:



This is the published engagement zone for the 5V55R missile, the OG weapon of the S-300PT/PS (SA-10A/B). This missile is of course much less performant than 48N6xxx and 40N6, but their design fundamentals are identical (single-stage short-burn boost-sustain rocket, with lofted trajectory).

The first thing to note is that the envelope does not follow the classic "bubble" coverage at all; it is actually "inverted": The higher the target altitude, the longer the engagement range. Compare the range against a target at 10km height vs a target at 20km.

Initially this doesn't seem to make sense - after all, to get to higher altitude we sacrifice energy which would otherwise be spent on extra range, right? This would be true if we are shooting on a planet with negligible atmosphere (e.g. the moon). But on Earth, atmosphere gets a very heavy vote, and the more time the missile spends in its lower strata the worse its performance gets.

This, for example, is why the "maximum range" elevation angle for a gun shot is not the theoretical 45 degrees but a slightly lower 42-43. It is also part of why railguns can deliver shots at disproportionally longer ranges than conventional guns; the higher muzzle velocity not only generates a longer parabolic trajectory, but most importantly raises the projectile much higher above the thick atmosphere, offering it a low-drag flight - just like in the high-altitude target trajectory in the 5V55R graph above.

Hopefully I'll be able to elaborate on the other factors later today.

[thewood1]

Part of the problem for me is that in fluid and aerodynamic courses in engineering school, all calculations were done assuming no fluid friction or drag to make the energy calculations easier to complete within the framework of the course. Drag and friction were considerations were for more advanced courses.

[Dimitris]

Next element: WRA firing range.

In this predicament I think a 75% value is a bit forgiving toward the target, a high-performance fighter. As a (very crude) point of reference, I distinctly remember in Falcon 4 the SA-5C would fire against F-16s at around 43nm (against a nominal max range of ~160nm, so approximately 25% in WRA-range terms).

Testing with a 50% figure usually results in more reliable impacts.

There is an argument to be made that WRA-range figures should be tailored to the known target type (e.g. greater percentage against ISR or tankers), but this doesn't cater to cases where the target has not been type-classified. In any case this harkens back to numerous previous discussions on this forum on the matter of WRA-range values.

========================
Sidebar: Strictly speaking, LR-SAMs don't need a high PH in order to do their job as part of an integrated AD network

Surprised? Read Stuart Slade's (RIP) excellent article on NavWeaps on how traditional (hierarchical) IADSs are structured: http://www.navweaps.com/index_tech/tech-032.php
Choice quote:

So now we come to weapons (note, right at the end of a prolonged system). Some will be batteries of very long range missiles. these strike at high-altitude targets, those just entering the defended zone, those coming in along unanticipated routes or just launched to shake up the attackers. They have a lot of roles other than shooting down aircraft; they break up carefully calculated formations, force the attackers to burn fuel with evasive maneuvers, add to the general air of gloom and despondency. Its quite possible that inexperienced pilots under this type of attack will fly into the ground trying to evade missiles that are actually of little threat to them. The long-range missiles will have big warheads that can damage aircraft even if it doesn't kill them. These big missiles can be equated to barrage fire from artillery: the kill rate isn't high but that's not the point (although against an unsophisticated or careless enemy these long-range missiles can be devastating).

This vewpoint is reinforced by historical experience and especially the Vietnam and Yom Kippur wars, where SA-2 & SA-6 missiles often had mediocre individual PHs but were very effective at driving their targets towards other gun/missile systems that actually decimated them. See this (unusually "operational") article by Carlo Kopp as an example reference: https://www.ausairpower.net/APA-SAM-Effectiveness.html
End of Sidebar
=========================

As part of the next update release (accompanying the Desert Falcon DLC), Brandon has set the default WRA-range figure on all official scenarios to 50%, so cases like this should be reasonably covered.

I will next discuss aircraft acceleration, which (spoiler) looks to me as the biggest culprit in this case.

[Quark73]

That may a point, we often do not give enough attention to the mission kill aspect. Often it is enough to prevent the opponent from carrying out his mission.
In addition, through C:MO we can learn how another Russian Wunderwaffe is disenchanted by the simple (or complex) laws of physics. Thanks for that educational part of C:MO.

[thewood1]

If you go back and look at the WRA discussions. It was specifically called out that trying to set WRAs based on type of aircraft is a forlorn hope. I postulated that is was more important to know missions. If you're goal is attrit, NEZ. If your goal is to force defensive, max. Some people only think in terms of a very narrow one-on-one approach to AAM and SAM engagements. Thats why I have kept on asking for a full scenario run through with the impact of changes.

[Horchata]

Can someone explain the tl;dr of all the charts and graphs above? is the new behavior actually realistic? I am in any case confused how secretive systems like the 40N6 are modeled or what its actual intended use case is for.

That may a point, we often do not give enough attention to the mission kill aspect. Often it is enough to prevent the opponent from carrying out his mission.

Unfortunately it is very hard to add this to a scenario, even an average skill human SAM crew is *always* going to be better than the terrible ones in DCS or the non existent AI in CMO because they can do more than fire missile at X range. Same as a human pilot could consider the missile was bullshit and press on anyway.

In addition, through C:MO we can learn how another Russian Wunderwaffe is disenchanted by the simple (or complex) laws of physics. Thanks for that educational part of C:MO.

It was the usual poorly informed journalists that don't things like understand radar horizon who came up with the stupid A2AD/400km circle of death idea not the actual manufacturer.

I believe the 400km figure is more for larger bomber/missile carrier sized aircraft that can't maneuver much and I believe the 40N6 at least the export version was originally marketed as an AWACS killer
Notwithstanding that the S400 has made some very impressive shots, like when it hit a low altitude MiG-29UB in Kiev all the way from Belarus with some sort of low altitude assist system (rumored A-50U CEC?). Everything that day was working perfectly including the IFF/NCTR so they also didn't accidentally target the helicopters the MiG-29 was only seconds from destroying. If they were using an active seeker missile it wouldn't have much time to maneuver.

[Dimitris]

the non existent AI in CMO

I would appreciate avoiding generalizations like that. As I recently wrote on a Steam thread:

Perhaps we should make a special "no AI" build of Command, with absolutely all AI-driven decisions disabled, so that you can indeed experience what a Command-like game with truly no AI would play like.

It wouldn't be fun, but it would hopefully be illuminating.

Thank you for your understanding.

[Dimitris]

It was the usual poorly informed journalists that don't things like understand radar horizon who came up with the stupid A2AD/400km circle of death idea not the actual manufacturer.

I believe the 400km figure is more for larger bomber/missile carrier sized aircraft that can't maneuver much and I believe the 40N6 at least the export version was originally marketed as an AWACS killer.

That is broadly correct. One of the main tasks of LR-SAMs has historically been to keep "key enablers" such as ISTAR, tanker, EW and C2 aircraft as far back from the front line as possible. Shots against such targets are feasible with a fair chance of success even at close-to-maximum range. High-performance aircraft are a significantly harder target and are best engaged at significantly shorter ranges or ideally handed off to other systems (ground or airborne).