w.i.p. Many missiles in the game still have the max speed bug (same as Patriot before the fix)

[Skuva]

Earlier this year a problem with the Patriot missile max speed was reported, acknowledged and fixed.

But even though other missiles got reported in that thread they got overlooked and haven't received a fix to this date.

 

I perceived this problem initially with the S-25L missile, that behaves way too different from it's dumb cousins S-25O/OFM.

 

After some more investigation I found out this speed cap is plaguing many missiles in the game, most of them SAM's. From what I managed to test, the ones with problems are HAWK, SA-2, SA-3, SA-6, SA-8, SA-11, SA-15, HQ-7.

To be more specific, the bug refers to the missile hitting a max speed wall during flight that makes no sense with how solid motor work, physics work, or with real life data. It is clearly noticeable with the S-25L as you can fire it in a dive and after hitting the "wall" the missile begins to decelerates as it descents even if it is still burning, because the "wall" seems to be a function of altitude. Also clear by how the Hawk's fire control completely overestimates its range and fail to hit a target moving straight.

The SA-10 and Patriot are currently working as expected. I don't know of other problematic SAM or A/G missiles apart from these, but there could be more, if anoyone else could help testing.

SA11_speed_bug.trk Hawk_speed_bug.trk S-25_speed_bug.trk SA2_speed_bug.trk SA3_speed_bug.trk SA6_speed_bug.trk

SA8_speed_bug.trk SA15_speed_bug.trk HQ7_speed_bug.trk

Edited October 21, 2023 by Skuva
More missiles tested

[Default774]

Some more details on the hawk in its own dedicated post here.

SM-2 is also affected as is shown in the patriot post you linked.

I imagine this is mostly an issue with the legacy SAM scheme that will get fixed over time as the SAMs get redone.

Edited October 21, 2023 by Default774

[DSplayer]

Looking at this again, like what Default said, all these missiles use an extremely old version of the missile API without any model data for drag and other important bits standard to missiles in DCS. The way that was seemingly fixed for the Patriot was the addition of a ModelData section back in May. 

Really hoping they actual add them

[Flappie]

On 10/20/2023 at 5:46 PM, Skuva said:

To be more specific, the bug refers to the missile hitting a max speed wall during flight that makes no sense with how solid motor work, physics work, or with real life data. It is clearly noticeable with the S-25L as you can fire it in a dive and after hitting the "wall" the missile begins to decelerates as it descents even if it is still burning, because the "wall" seems to be a function of altitude. Also clear by how the Hawk's fire control completely overestimates its range and fail to hit a target moving straight.

I've just checked your S-25L track and I don't see the missile decelerate before the rocket motor stops. Have things improved or am I missing the wall?

Edited December 18, 2023 by Flappie

[Skuva]

15 hours ago, Flappie said:

I've just checked your S-25L track and I don't see the missile decelerate before the rocket motor stops. Have things improved or am I missing the wall?

 

The problem persists. Here is a track that should make it more obvious. Look how when it reaches 1664kmh, it just stops accelerating still burning for a good 3 seconds.

S-25L_speed_bug2.trk

Edited December 19, 2023 by Skuva

[Hobel]

vor 2 Stunden schrieb Skuva:

The problem persists. Here is a track that should make it more obvious. Look how when it reaches 1664kmh, it just stops accelerating still burning for a good 3 seconds.

S-25L_speed_bug2.trk 37.86 kB · 1 Download

 

Interesting, have you already tested this with the aim120 and similar missles ?

[Skuva]

20 hours ago, Hobel said:

Interesting, have you already tested this with the aim120 and similar missles ?

I tested many of the more common a2a missiles (including aim-120B/C), they behave normal in this regard.

I got some more testing comparing the S-25L and S-25OFM, being fired at the same target in quick succession. And this time used tacview data to ilustrate the flight profile. Data captured from this track

S-25L_O_OFM_test.trk

Although it may look like the L is smoothly transitioning into that constant speed regime, it's a tacview's quirk thing. When looking in-game and into raw data, we see it is a very sudden change from accelerating, and then imediately a flat line. As I mentioned in that S-25 post, I managed to find no clue that these rockets use different burners, they both weight approx the same, and everywhere I managed to find specs values points the L variant should reach close to mach 2.

 

All the SAM missiles I pointed in this Thread presents the same behaviour as the Blue line. The Patriot used to show the same, but after ED fixing it, it started to look like the Green line.

 

EDIT: Throwing the kh-25 into the mix shows even more the problem. It is a different missile, but has very similar T/W to the S-25L. From this we can see this speed limit could not be caused by simply drag or a slower burner.

Edited December 20, 2023 by Skuva

[BOBBER_REBBOB]

Any updates? Is this being worked on or should we provide more data?

[Skuva]

On 4/23/2024 at 8:53 AM, BOBBER_REBBOB said:

Any updates? Is this being worked on or should we provide more data?

They fixed the HQ-7 tracking but not the burn, it can at least hit targets sometimes I guess. Due to the update the track got broken, here is a new one.

EDIT: Not sure if the HQ-7 tracking should behave like this, the missile just go most of the flight zig zagging towards the target.

HQ7_speed_bug.trk

Edited April 24, 2024 by Skuva

[Exorcet]

I believe the XMIM-115 of the Roland also suffers from this issue.

[BOBBER_REBBOB]

I have conducted some tests with SA-2, SA-3, SA-6 and SA-11. All of their missiles hit an artificial speed cap. Hope this gets looked at.

TestSA-3.trk TestSA-2.trk SA-6.acmi SA-3.acmi TestSA-6.trk TestSA-11.trk SA-2.acmi SA-11.acmi

[paco2002]

On 4/25/2024 at 7:29 PM, BOBBER_REBBOB said:

I have conducted some tests with SA-2, SA-3, SA-6 and SA-11. All of their missiles hit an artificial speed cap. Hope this gets looked at.

TestSA-3.trk 85.13 kB · 1 download TestSA-2.trk 134.83 kB · 1 download SA-6.acmi 18.71 kB · 0 downloads SA-3.acmi 17.13 kB · 0 downloads TestSA-6.trk 77.13 kB · 0 downloads TestSA-11.trk 102.86 kB · 2 downloads SA-2.acmi 17.11 kB · 1 download SA-11.acmi 25.9 kB · 0 downloads

Can confirm, this is still in the game, and it's quite annoying, it reduces a lot the range of the missiles

 

[BOBBER_REBBOB]

Months have passed, patches have been released, we still don't know if this is being worked on or even has been aknowledged by the team

[Flappie]

On 12/19/2023 at 4:03 PM, Skuva said:

The problem persists. Here is a track that should make it more obvious. Look how when it reaches 1664kmh, it just stops accelerating still burning for a good 3 seconds.

S-25L_speed_bug2.trk 37.86 kB · 11 downloads

The S-25L appears to have been fixed.

[Flappie]

On 4/25/2024 at 1:02 AM, Skuva said:

They fixed the HQ-7 tracking but not the burn, it can at least hit targets sometimes I guess. Due to the update the track got broken, here is a new one.

HQ-7 missile issue is not fixed. It clearly hits a wall at ~2330 km/h, it slows down a bit, then accelerates again but very slightly (2337 km/h when the engine shuts off).

Issue reported.

[Flappie]

SA-3 missile hits a speed wall as soon as the booster separates.

Issue reported.

[Flappie]

Exact same issue for SA-2 reported.

SA-6 and SA-11 reported as well.

Thank you both, @Skuva and @BOBBER_REBBOB.

Edited June 2, 2024 by Flappie

[Skuva]

2 hours ago, Flappie said:

Exact same issue for SA-2 reported.

SA-6 and SA-11 reported as well.

Thank you both, @Skuva and @BOBBER_REBBOB.

 

Don't forget the SA-8, SA-15 and of course the Hawk (its the most affected one). My original tracks in the first post are still working and showing the problem.

The S-25L indeed look very much fixed

now there is a reason to bring it insted of the Kh-25, as it now have shorter time to target on ranges below 5km.

EDIT: It seems now the S-25L is capable of hiting targets faster than the Kh-25 at ranges greater than 13km (due to lower drag). Even weirder, while the Kh-25's seeker only starts tracking at 8km, the S-25L seems to be able to track from unlimited distances, I tested up to 50km and it still turned towards the target even though this is well beyond self-destruct distance. It might be lacking the seeker rework the other missiles went through recently. Here is a track showing a S-25L clearly starting its turn right a launch and hiting a target 20km away.

S-25L_20km.trk

Edited June 2, 2024 by Skuva

[Flappie]

SA-8, SA-15 and Hawk reported, sir.

[Flappie]

Devs answered: the problem exists because all these weapons have not received the new missile dynamics yet. Its implementation will be made progressively (we can see it was applied recently to the S-25L, for instance).

[Skuva]

Wonderful to know it is already being worked on.

For the sake of science I'll leave some of my measurements here to compare in the future as these missiles get updated.

Edited June 3, 2024 by Skuva

[Hobel]

Am 3.6.2024 um 15:07 schrieb Skuva:

Wonderful to know it is already being worked on.

For the sake of science I'll leave some of my measurements here to compare in the future as these missiles get updated.

 

Wow, 10-30s burn time that is not used effectively, I'm really curious how the performance will turn out when this is fixed

[Skuva]

52 minutes ago, Hobel said:

Wow, 10-30s burn time that is not used effectively, I'm really curious how the performance will turn out when this is fixed

I can see the Hawk getting way way better, as currently its top speed is so much lower than real life specs that even the AI fails to properly lead the thing into the target.

Now other systems like the Sa-15 might see a slight reduction in effectiviness, as its max speed is already near the real thing, but properly modeling the booster and sustained phases could prolong the speed ramp up, taking it a few extra seconds to hit the maximum speed. Something like this green line

Edited June 4, 2024 by Skuva

[Default774]

1 hour ago, Skuva said:

I can see the Hawk getting way way better, as currently its top speed is so much lower than real life specs that even the AI fails to properly lead the thing into the target.

 

I put something together for the hawk specifically a year ago. HAWK should benefit a lot from a proper missile flight model.

Hope this gets addressed sooner rather than later, but what can you do I guess.