Aim120 can be trashed with a barrel roll and chaff headon

[Hobel]

vor 21 Stunden schrieb Red_Camarada:

from all tracks posted here and replayed the only one that resulted in a survivable barrel roll is this one. seems better than before.

AOA_Roll.trk 417.12 kB · 7 Downloads

yep but the window is much smaller, as I said.

i took control and just changed the timing a bit, and the missile then hits the fast-rolling target.
before the 15m update, the missile almost always flew past.
i think that the exploit has been reduced a lot, so that it is no longer a problem.

and also thanks to @Chizh for looking in and listening to our arguments.

 

 

Tacview-20250121-184501-DCS.txt.acmi

[Zergburger]

On 1/14/2025 at 12:17 PM, Chizh said:

Why would we do something that is not in a real missile?

Where did the information about Doppler come from?

Doppler? theres no doppler involved here, its just an IC measuring rate of change of the values coming in on the proximity fuze?

If you got doppler ideas from @NytHawk, he was referring to the navy's VT fuze which used doppler for a few select reasons:

1. It was like 2 vacuum tubes and a coathanger antenna, about as simple as a radar could possibly get. It was easier to measure frequency changes.

2. It made sure the fuze would work (read: not detonate on a false target) when shot at low angles against planes coming in for torpedo drops or ramming attacks.

We have integrated circuits and all kinds of fantastical gadgets now, so we can make a TDD to do whatever we want.

Edited January 23 by Zergburger

[Chizh]

39 минут назад, Zergburger сказал:

Doppler? theres no doppler involved here, its just an IC measuring rate of change of the values coming in on the proximity fuze?

What should be the fuse algorithm in this case?

 

[Coxy_99]

4 hours ago, Chizh said:

What should be the fuse algorithm in this case?

 

He does not know

[Zergburger]

9 hours ago, Chizh said:

What should be the fuse algorithm in this case?

 

let BOOM = dist <= min || (d(dist)/d(t) <= 0 && dist <= max)

When missile range to target reduces beneath the stated initial proximity fuse range [MAX] (50m for this example). The fuse then begins to take measurements of range over time for comparison, creating a rate. When the range rate is found to decrease under zero then trigger the fuse.

This can make use of Kalman filtering to throw out any garbage positional updates that would prematurely indicate a negative closure.

Once the missile either stops closing (decreases below zero or an other minimum closure threshold) towards the target, or the missile hits a set minimum range (for example, the previous 9m) it will detonate. This will mean that if a missile for example gets within the initial 50m range to the target, and makes it as close as for example 20m, it will detonate as soon as it stops closing with the target. The missile will now detonate, causing less significant damage instead of flying past harmlessly. This means realistic missile avoidance maneuvers that increase the missiles miss distance will be effective, possibly making a missile hit non-fatal. This allows for missiles that are near-misses to then become at least partially viable instead of a trashed shot.
 

So here we have a system where missile avoidance maneuvers are still viable in reducing the lethality of incoming shots, but also a system where missiles that would have been worthless now still pose some sort of risk for the aircraft.

I have included some documents on the history of proximity fuses [1] and an explanation of modern use FFTs for ranging of proximity fuses [2]

 

1. https://www.ijert.org/research/recent-advancements-in-proximity-fuzes-technology-IJERTV4IS041400.pdf

2. https://ieeexplore.ieee.org/document/10418854

 

Also, Thank you Coxy for your extremely valuable contribution to this discussion

Edited January 23 by Zergburger

[Zergburger]

@Chizh
Any thoughts or updates on this concept?

[nighteyes2017]

From what i have seen the last five missions i have flown, this is still an issue. The ai is able to dodge aim120's by barrel rolling. The acmi's from those missions clearly shows multiple ai thrashing multiple missiles by rolling. Is this still on ED's radar?

 

[Hobel]

vor 1 Stunde schrieb nighteyes2017:

From what i have seen the last five missions i have flown, this is still an issue. The ai is able to dodge aim120's by barrel rolling. The acmi's from those missions clearly shows multiple ai thrashing multiple missiles by rolling. Is this still on ED's radar?

 

As always, a track or tacview would be helpful.  

 

[nighteyes2017]

yeah, i'll try to make an extraction from different situations on the acmis, and pile them together.

 

[Muchocracker]

You're gonna have to be more specific than "it's still an issue". It's been pretty well established now in this thread that the ability to defeat the amraam with loaded barrel rolling is not suppose to go away entirely. Just be more difficult to get away with. Is it missing outside of the proximity fuse distance (that was changed to 15 meters), or is it missing within the PF distance? The latter is likely gonna be an issue with the new warhead frag pattern. 

[artao]

Perhaps this should be in a new topic, but it sure seems related. Not me, a video that YouTube popped at me. Dude is going against a swarm of SAMs no problem. Ridiculous.
I commonly see people defeating missiles way too easily in DCS.

Roll Defeating SAM Swarm

[NytHawk]

1 hour ago, artao said:

Perhaps this should be in a new topic, but it sure seems related. Not me, a video that YouTube popped at me. Dude is going against a swarm of SAMs no problem. Ridiculous.
I commonly see people defeating missiles way too easily in DCS.

Roll Defeating SAM Swarm

He's just over-Ging these missiles. Realistic behaviour.

Edited May 31 by NytHawk

[Hobel]

vor 15 Stunden schrieb artao:

Perhaps this should be in a new topic, but it sure seems related. Not me, a video that YouTube popped at me. Dude is going against a swarm of SAMs no problem. Ridiculous.
I commonly see people defeating missiles way too easily in DCS.

Roll Defeating SAM Swarm

This is still an old video and the proxy fuze of this missile seems much too small, in the last few months there have been some fixes where some missiles have gotten significantly more PF range and something like in the video is no longer possible.

[Dragon1-1]

15 hours ago, artao said:

I commonly see people defeating missiles way too easily in DCS.

Do note that in DCS, we're able to practice fighting "real" missiles in ways that would, IRL, be considered too risky to ever try to use. Physics say that this should work, but if you tried that IRL, you'd be called a madman. If you get it wrong, you get a SAM right to the face. Generally, you defend against a SAM launch by turning cold and getting out of its WEZ.

That said, Stroke 3 famously dodged a whole swarm of SA-3s by maneuvering alone, during the Package Q strike. Of course, Stroke 1 and 2 weren't so lucky.

[Pavlin_33]

On 6/1/2025 at 2:08 AM, Dragon1-1 said:

Do note that in DCS, we're able to practice fighting "real" missiles in ways that would, IRL, be considered too risky to ever try to use. Physics say that this should work, but if you tried that IRL, you'd be called a madman. If you get it wrong, you get a SAM right to the face. Generally, you defend against a SAM launch by turning cold and getting out of its WEZ.

That said, Stroke 3 famously dodged a whole swarm of SA-3s by maneuvering alone, during the Package Q strike. Of course, Stroke 1 and 2 weren't so lucky.

There is a reason why SAM missiles are like flag poles. How big is their blast radius in DCS?

[Hobel]

vor 3 Minuten schrieb Pavlin_33:

There is a reason why SAM missiles are like flag poles. How big is their blast radius in DCS?

this is also discussed here with interesting irl pictures.

as already mentioned, the video shown is very old and many missiles in DCS have received a drastic increase in proximity fuze
range in the last few months.

I no longer know the exact number, but it should be ~75m now

 

[Dragon1-1]

43 minutes ago, Pavlin_33 said:

There is a reason why SAM missiles are like flag poles.

That reason is actually that getting the missile going from zero to speeds needed to intercept a high speed aircraft takes a pretty big rocket, especially if said aircraft is also flying high. Early SAMs did have rather large warheads, but that's more because they were expected to be used against large, nuke-armed bombers, where merely damaging the aircraft wouldn't be enough, you wanted it to disintegrate. The modern trend is to reduce the warhead size and expand maximum range and altitude, as well as maneuverability.

In DCS, the blast radius should be pretty accurate. An important matter is also that fragmentation, even without an expanding rod warhead, retains the missile's velocity, and thus is more of a cone pointed ahead of the missile. If the missiles can't point its nose in front of the target aircraft (it's basically like trying to shoot it with a shotgun), then the fragments will miss. 

[Pavlin_33]

18 hours ago, Dragon1-1 said:

That reason is actually that getting the missile going from zero to speeds needed to intercept a high speed aircraft takes a pretty big rocket, especially if said aircraft is also flying high. Early SAMs did have rather large warheads, but that's more because they were expected to be used against large, nuke-armed bombers, where merely damaging the aircraft wouldn't be enough, you wanted it to disintegrate. The modern trend is to reduce the warhead size and expand maximum range and altitude, as well as maneuverability.

In DCS, the blast radius should be pretty accurate. An important matter is also that fragmentation, even without an expanding rod warhead, retains the missile's velocity, and thus is more of a cone pointed ahead of the missile. If the missiles can't point its nose in front of the target aircraft (it's basically like trying to shoot it with a shotgun), then the fragments will miss. 

There is no kinematic miss in a no-escape zone of a missile.

Also there is zero modeling of blast fragments which is a big deal. I don't know of any Soviet SAMs scoring a direct kill, like in DCS. It's always some indirect hit.

[Dragon1-1]

2 hours ago, Pavlin_33 said:

There is no kinematic miss in a no-escape zone of a missile.

Of course there is, NEZ refers to the missile being able to chase down the target if it turns and runs at the moment of launch. That doesn't mean a kinematic defeat is impossible. Even if the missile has enough energy to hit you, it doesn't mean that it has the G to do so.

[Pavlin_33]

6 hours ago, Dragon1-1 said:

Of course there is, NEZ refers to the missile being able to chase down the target if it turns and runs at the moment of launch. That doesn't mean a kinematic defeat is impossible. Even if the missile has enough energy to hit you, it doesn't mean that it has the G to do so.

Are you sure about this?

It is my understanding that within NEZ the missile can be defeated only by breaking some other link in the intercept chain, like tracking for example.

I would assume that missile would out maneuver the target as it can pull some 4-5 times more G.

Maybe SAMs don't have NEZ? Not sure.

---

Just checked out a BUK missile and it looks like it can pull around 20G.

So I guess it would be possible to outmaneuver.

 

Edited June 7 by Pavlin_33

[Dragon1-1]

2 hours ago, Pavlin_33 said:

It is my understanding that within NEZ the missile can be defeated only by breaking some other link in the intercept chain, like tracking for example.

Your understanding is incorrect. NEZ is the no escape zone, not no dodge zone. There's no place in any missile's envelope where it's impossible for it to miss, though tail aspect shots tend to have very high Pk... if you are in range in first place, since range against a receding target is very short compared to range against a closing one. With any other shot, the missile has to fly to a point in front of you in order to hit. At long range and high speed, this point is quite far ahead, so if you crank one way to the antenna gimbal limit, then pull through to the other extreme, you're forcing the missile into a high G turn across the entire angle. Even if it's within the missile's G limit, such turns cost energy (just like they do for you), but the missile can't regain energy (unless it's a fancy, extremely long ranged one like the Meteor). In most scenarios, such turn, if properly timed, will result in the missile bleeding off all of its energy.

As such, what happens inside the NEZ (if you can't avoid going there) is that you switch your defensive strategy from simple turning and running to something like the F-pole maneuver/SAM break (they're both actually the same concept, just applied against AAMs or SAMs), plus expendables. Outside of it, turning cold and plugging in the blower is guaranteed to trash the missile. In fact, there's usually no point in wasting expendables in such case. Inside the NEZ, you have to put actual effort into defeating the launch.

Incidentally, a high G barrel roll would work along the same way as the F-pole maneuver, with an important tactical disadvantage, that you're locked into driving straight towards the missile. The F-pole maneuver allows you to manage your closure with the bandit, by varying the angle of your crank, and also puts you in a position to shoot your own missiles when you're pulling your nose across, which the barrel roll would complicate. Likewise with SAMs, doing that IRL would probably put you within flak envelope. Not saying they'd hit you, either (especially if radar guided, manually aimed ones might get lucky), but at some point you have to stop flying towards the SAM site and do something. 

[Red_Camarada]

11 hours ago, Dragon1-1 said:

Your understanding is incorrect. NEZ is the no escape zone, not no dodge zone. There's no place in any missile's envelope where it's impossible for it to miss, though tail aspect shots tend to have very high Pk... if you are in range in first place, since range against a receding target is very short compared to range against a closing one. With any other shot, the missile has to fly to a point in front of you in order to hit. At long range and high speed, this point is quite far ahead, so if you crank one way to the antenna gimbal limit, then pull through to the other extreme, you're forcing the missile into a high G turn across the entire angle. Even if it's within the missile's G limit, such turns cost energy (just like they do for you), but the missile can't regain energy (unless it's a fancy, extremely long ranged one like the Meteor). In most scenarios, such turn, if properly timed, will result in the missile bleeding off all of its energy.

As such, what happens inside the NEZ (if you can't avoid going there) is that you switch your defensive strategy from simple turning and running to something like the F-pole maneuver/SAM break (they're both actually the same concept, just applied against AAMs or SAMs), plus expendables. Outside of it, turning cold and plugging in the blower is guaranteed to trash the missile. In fact, there's usually no point in wasting expendables in such case. Inside the NEZ, you have to put actual effort into defeating the launch.

Incidentally, a high G barrel roll would work along the same way as the F-pole maneuver, with an important tactical disadvantage, that you're locked into driving straight towards the missile. The F-pole maneuver allows you to manage your closure with the bandit, by varying the angle of your crank, and also puts you in a position to shoot your own missiles when you're pulling your nose across, which the barrel roll would complicate. Likewise with SAMs, doing that IRL would probably put you within flak envelope. Not saying they'd hit you, either (especially if radar guided, manually aimed ones might get lucky), but at some point you have to stop flying towards the SAM site and do something. 

The thing that you are describing is an energy defense manuveur right? You are making the missile spend its energy into Gs, but this is not possible inside NEZ because the missile has plenty of energy to intercept you. It only works when there is no sufficient atmosfere to change missile direction based on its velocity, in this case despite energy state there is no air enough to change missile direction to the intercept vetor.

[Ironhand]

21 hours ago, Dragon1-1 said:

…Even if the missile has enough energy to hit you, it doesn't mean that it has the G to do so…

This seems like an very odd statement to me. If it has the energy to hit you, then it can produce the Gs to hit you. It’s converting the energy into Gs. If it can’t produce the Gs, it didn’t have the energy it needs to hit you.

[Muchocracker]

Yes it's a little bit of a contradictory statement. The range that the missile can chase down a cold target is the minimum abort, not the no escape. 

The no escape zone is really where the missile has enough airspeed (and lift to create the required G) to match most or all evasion maneuvers except for going fully cold and accelerating in the opposite direction. But where that line is isnt always the same. By using the crank and F-Pole you can shrink that NEZ because it's forcing the missile to do drag inducing mid G turns to match them. This doesn't actually defeat the missile at all and isnt suppose to in an A2A context, but what it does is buy yourself time to close the distance and make *your* own missiles deadlier. While reducing the amount of time you have to stay cold to fully trash that missile. 

[Dragon1-1]

8 hours ago, Ironhand said:

This seems like an very odd statement to me. If it has the energy to hit you, then it can produce the Gs to hit you. 

Only if its airframe is made out of vibranium. Missiles have structural G limits, those tend to be large compared to fighters, but during an F-pole maneuver for instance, the fighter is very much capable of forcing the missile to make a 20G+ turn. Missiles are typically very fast when fired directly at the target, and that means even a gentle maneuver will generate a lot of Gs. Of course, missiles that loft are less vulnerable to this, but the longer the range, the more lead the missile must pull.

7 hours ago, Muchocracker said:

This doesn't actually defeat the missile at all and isnt suppose to in an A2A context, 

Sweeping your nose across from one gimbal to the other very much does defeat the missile. If it can't follow your turn due to hitting the G limiter, it'll pass behind you. Same if you get the missile to bleed off all its energy trying to make the turn. The nice thing is, unless the missile is lofting, it'll be either fast enough to have G issues, or slow enough that the maneuver will bog it down. In fact, that's exactly how they dodged SA-2s in Vietnam. It helped that the version of SA-2 they faced didn't have a particularly high G limit.

7 hours ago, Muchocracker said:

The range that the missile can chase down a cold target is the minimum abort, not the no escape. 

The way I've seen it explained was that NEZ was defined as the minimum range where the missile can chase down the target if the target turns cold and maintains its current speed. The MAR is a related concept in BVR timelines, and might actually be slightly shorter than the NEZ defined that way, since the defending fighter might unload to accelerate.