AIM-54 Changes / new API fixes are live in today's patch

[GGTharos]

 

Theoreticall yes. This would make it active off the rail but still receive mid-course corrections as long as a lock is held.

 

Theoretically no. There's no evidence that you can do anything like this at all, and there are hints that the missile ignores DL once active - it's been a long while since I've read that manual though.

[Noctrach]

Considering the age of the missile and the size considerations of batteries... Would launching it active not just cause the the battery running dry mid-way through the shot?

Active scanning costs a whole lot more juice than homing SARH or flying on DL.

 

As such I highly doubt that was a possibility.

[r4y30n]

Well if it's active off the rail it's also not lofting so there's no sense in trying to go for a long shot that way. I think it was Okie who said it was pretty badass around 10 nm in ACM mode.

[*Aquila*]

Considering the age of the missile and the size considerations of batteries... Would launching it active not just cause the the battery running dry mid-way through the shot?

Active scanning costs a whole lot more juice than homing SARH or flying on DL.

 

As such I highly doubt that was a possibility.

 

Depends on how long it flies. Not sure the active from the rail feature is intended for BVR purposes (euphemism intended).

[Noctrach]

Ya but in that case you can just fire it in any of the PLM/PAL modes, which will give it an azimuth and altitude and tells it to go play fetch.

[Eagle7907]

My observations include engaging 2 Foxhounds. With jammer on (yes it keeps them from firing at great distance), I launch at them, one a piece, then crank to 45 angle because they shortly firing later, then go complete 90 because defensive, missiles lose track and miss. I’m very confident it was before the 15 second timer.

 

Rinse and repeat, and I die.

 

RIP

 

 

Sent from my iPhone using Tapatalk Pro

[sLYFa]

Are you sure the changes made it in this patch? I see zero difference at all. TTIs are still insanely off, sometimes showing 30s when the missile is on target. Phoenixes also go active without a blinking indicator when close to the target (15nm IIRC) but TTI well above 16 as evidenced by an insane pull down (which also bleeds a ton of energy as before) . You are also stuck in TWS auto until your missile either hits the target or the ground, with the radar steering onto ghost tracks that are way off the actual target. Re-engaging a target after it was lost and reappered as a new track will not give a TTI at all, although the missile will track and eventually hit. The TWS steering priority in this scenario remains with the ghost though, sometime steering the radar away from the actual track.

There's also no apparent change in guidance logic. The high G pulldown is still there. PH will also still go crazy for chaff and veer around agressively eventually either running out of energy or loosing the target.

If thats the way these missiles worked IRL I would suggest the USN sues Hughes/Raytheon...

[QuiGon]

Are you sure the changes made it in this patch?

 

Keyword is "might":

 

Now Eagle Dynamics helped fix some of the remaining issues on their side, which means that the new API might be working as of today's patch, but it is not well tested yet. Equally it is not in the patch notes, as we did not commit anything really, however the changelog entry is planned for Nov 18th.

 

;)

[Eagle7907]

Are you sure the changes made it in this patch? I see zero difference at all. TTIs are still insanely off, sometimes showing 30s when the missile is on target. Phoenixes also go active without a blinking indicator when close to the target (15nm IIRC) but TTI well above 16 as evidenced by an insane pull down (which also bleeds a ton of energy as before) . You are also stuck in TWS auto until your missile either hits the target or the ground, with the radar steering onto ghost tracks that are way off the actual target. Re-engaging a target after it was lost and reappered as a new track will not give a TTI at all, although the missile will track and eventually hit. The TWS steering priority in this scenario remains with the ghost though, sometime steering the radar away from the actual track.

There's also no apparent change in guidance logic. The high G pulldown is still there. PH will also still go crazy for chaff and veer around agressively eventually either running out of energy or loosing the target.

If thats the way these missiles worked IRL I would suggest the USN sues Hughes/Raytheon...

 

Forgive me, but you're mentioning lots about the TTI and indications on the radar display. I think IronMike is talking about just the missile behaviors and that it tracks/doesn't track when it's supposed to. From what I understand, the TTI is still being refined and yet to be completed. Someone correct me if I'm wrong here.

[sLYFa]

I may have misunderstood but my understanding was that with the new API, TTIs would become more precise as it is a crucial parameter for the missile to go active. Right now, I don't see any of that, with missiles going active regardless of TTI (TTI either being above 16 or no TTI indication at all as mentioned earlier). I understand that a WCS computed TTI will never be exact, but indicating 140s on a 70nm head on shot with 1700kts closing velocity doesn't seem right.

[Eagle7907]

I may have misunderstood but my understanding was that with the new API, TTIs would become more precise as it is a crucial parameter for the missile to go active. Right now, I don't see any of that, with missiles going active regardless of TTI (TTI either being above 16 or no TTI indication at all as mentioned earlier). I understand that a WCS computed TTI will never be exact, but indicating 140s on a 70nm head on shot with 1700kts closing velocity doesn't seem right.

 

Oh I agree with you. It's not right either and I get the same indication. I thought there was a bug post about this, but its being difficult for me since many use "TTI" for "Through the Inferno". LOL However, my understanding is this relates purely to missile behavior/tracking. The only way to really find out if its working correctly is by tacview and a stop watch.

[sLYFa]

 

However, my understanding is this relates purely to missile behavior/tracking

 

But thats exaclty the point. If there are still 30s on the clock when the missile is practicaly on target (which is what I see especially for long range/high altitude engagements), the missile will never go active and I don't think TWS command steering will be enough to actually hit the target.

[GGTharos]

Please note: the 16 seconds TTI will not always be exact, as DCS doesn't have a simulated missile flyout, etc!

 

Hi IM, long time! I don't know how you guys compute TTI, but right it's not merely 'not exact', it is 'wildly off'.

 

So what I would suggest is this:

 

Generate a TOF table/graph vs. an non-maneuvering target.

 

Here's how you do this:

 

Compute TOF vs a 0 speed target (ie. you're computing missile flight time without the influence of target speed)

 

You do this for the following table:

 

Range (nm) Vl (M/TAS) El(Feet)

10 300 1000

20 300 1000

10 600 1000

20 600 1000

 

... You get the idea. It's a lot of work and it will have to be repeated for any FM adjustments, but you can reduce the work if you interpolate between points. Once you have this table, you need to account for target speed difference and altitude difference which can be done with a bit of logic for figuring out the altitude interpolation and a bit of math.

 

The point here is this: This gives you the absolute fastest time to target for the initial launch. Any maneuver will result in a TTI that is longer than the predicted TTI in all cases but one (the target accelerates), thus the active command will always be given before the missile reaches its target.

 

To account changes in target acceleration, you can update the TTI by using the current closure to modify the TTI with a bit of math. This doesn't take altitude changes into account yet, but altitude change should almost universally result in a longer TTI.

 

If you want to make the TTI even more accurate, you compute more pieces to that table, beginning by adding aspect at the time of launch. TOF is an important and non-trivial calculation and to make things work right, you'll need it.

[Eagle7907]

 

But thats exaclty the point. If there are still 30s on the clock when the missile is practicaly on target (which is what I see especially for long range/high altitude engagements), the missile will never go active and I don't think TWS command steering will be enough to actually hit the target.

 

Right, but what clock are you going by? The TTI clock or something else? Because if the TTI counter isn't right at launch, it won't be correct for pitbull or impact. That's why I'm saying to truly test if the missile does go pitbull 15 seconds before impact, then the only way to test is by using a stopwatch and viewing a replay on tacview. Is the jet coded to where the radar tells the missile to go pitbull, or is it just coded around the radar computation completely? IDK, maybe IronMike can answer that? From the looks of things it seems to be coded around it. How? Because the TTI calculation and -54 pitbull behavior are not in sync. Hence what you are getting at in your post above. I swear, I thought someone posted a bug report about this in the past. Anyways, we both agree on one thing, the AWG-9 indications are not correct. There is clearly an error in the TTI calculation, and therefore it doesn't give the player an accurate representation of when your missile does indeed turn pitbull. It seems closer to accurate when launched close, but the further away, the more inaccurate the timer gets, exponentially. However, my point is it doesn't necessarily mean the missile logic/behavior is 100% wrong. If it gets commanded to go pitbull roughly ~16 seconds before impact, and the missile reacts in such ways, then its correct, regardless of what TTI says. He's only asking about -54 behavior, not what the jet is showing you.

 

Edit: I take back my statement, IronMike does mention specifically the 16s of TTI on the TID. If that's the case then yeah, there's still major problems with the radar computing TTI and commanding the missile to pitbull. Hmm, hopefully it will get sorted out soon.

Edited November 4, 2020 by Eagle7907
I'm a dumb-dumb.

[IronMike]

Sadly this looks like the changes are not working at all. Hence how the TTI behaves has little bearing atm. Please keep testing though, the more feedback we can get, the better. We need to check if this particular change maybe did not make it from the trunk version into the release version, too.

 

Thank you for all your feedback thus far.

[*Aquila*]

My observations include engaging 2 Foxhounds. With jammer on (yes it keeps them from firing at great distance), I launch at them, one a piece, then crank to 45 angle because they shortly firing later, then go complete 90 because defensive, missiles lose track and miss. I’m very confident it was before the 15 second timer.

 

Rinse and repeat, and I die.

 

RIP

 

 

Sent from my iPhone using Tapatalk Pro

I engaged 2 Foxhounds that way with AIM-54A Mk60s and had no problem: first one killed in TWS, break when TTI = 16 sec; Second one killed in BRSIT. Tacview file joined.

Tacview-20201104-225823-DCS-Caucasus-AA-BVR.zip.zip

[Harlikwin]

Well someone posted this Aim54X behavior... Missile does a full 180 to engage.

 

I can't upload the mp4 here but this is the link.

 

 

https://images-ext-1.discordapp.net/...65ac0bf504.mp4

[dundun92]

Not only that, TWS AIM-54s arent giving pitbull warnings of any kind.

[foxwxl]

Hello HB mate, nice job for the implmention of the new missile API.

 

I've 2 simple question for the new API AIM-54 if your could please clarify (by your design when the missile is working properly):

 

1. Will the TWS SARH mid-course guidance trigger STT or MSL launch warning on target's RWR(since it is SARH guidance) or simply behave same as the normal TWS + MSL DL with only SCAN warning?

 

2. With PH ACT and launched in TWS, if the AIM54 seeker can not find any target, will the SARH DL still be available for the missile to locate the target?

 

Thx. Many people are interesting for these answers.

[captain_dalan]

Sadly this looks like the changes are not working at all. Hence how the TTI behaves has little bearing atm. Please keep testing though, the more feedback we can get, the better. We need to check if this particular change maybe did not make it from the trunk version into the release version, too.

 

Thank you for all your feedback thus far.

 

 

Only had time for 5 hops (4 are in this short vid), and only in SP. The only thing that seams different to me right now, is that the missile can actually reacquire the bandit even after going for the chaff IF the bandit exits the notch. I don't recall seeing this behavior before. I could be wrong though and it might just be a case of ME not noticing it. The TTI seams to have no bearing of any kind on missile behavior, or at least not one i could find. TV records show missiles changing trajectory and-or going active at proper ranges, but this was largely the case even before the change. Sorry i could not help more tonight. DCS gave me issues while updating and i could only finish the process after 3 failed attempts.

 

Will the experiment work with the AI shooting at me?

[Harlikwin]

Not only that, TWS AIM-54s arent giving pitbull warnings of any kind.

 

Yup can confirm that. Missile goes Pitbull, no RWR signature.

 

Any chance you guys can hotfix this? Seems like the 120X is a thing too, though those do show up on the RWR.

[Karon]

I did just a couple of tests yesterday. 20nm, 0TA, 20000ft. TTI still at 6" at the moment of impact.

Test two, switch to RWS right after launch, the missile was still supported until impact. As before, no TTI blinking.

[QuiGon]

Hello HB mate, nice job for the implmention of the new missile API.

 

I've 2 simple question for the new API AIM-54 if your could please clarify (by your design when the missile is working properly):

 

1. Will the TWS SARH mid-course guidance trigger STT or MSL launch warning on target's RWR(since it is SARH guidance) or simply behave same as the normal TWS + MSL DL with only SCAN warning?

 

2. With PH ACT and launched in TWS, if the AIM54 seeker can not find any target, will the SARH DL still be available for the missile to locate the target?

 

Thx. Many people are interesting for these answers.

 

Very great questions! I'm wondering about these exact things too!

 

 

Will the experiment work with the AI shooting at me?

 

No, AI behaves differently.

[IronMike]

Dear all, ED is watching this thread as well, however what we'd need would be short tracks of the several issues. If anyone of you could post short tracks (as short as possible), it would help a lot! Thank you!

 

A new confirmed bug now seems to be no RWR warning for aim-54s, too.

 

To answer above questions: 1. TWS mid course guidance will not trigger a launch warning, when it goes active it will trigger a MSL launch warning. 2. PH ACT launches the missile active off the rail, I am not sure whether it gets DL updates from the AWG-9 at this point anymore, I need to ask Naquaii or Gyro for that. My guess would be no.

 

EDIT: Naquaii got back to me: So IRL it would always fall back on SARH when it does not find a target on its own and to check it has the correct target. So even with ph act, in PDSTT and TWS it would indeed also use SARH/DL. However: this is not possible to recreate in DCS, as a missile that goes active pitbull in DCS cannot take commands anymore. Thus any ph act launched missile in DCS, will behave like an active pitbull missile and not receive SARH/DL guidance anymore. For any other mode than PDSTT or TWS this of course is also the case irl (and in game).

 

Thank you all for your kind and great input thus far. Obviously us and ED hoped it would work better than the results we are getting, but we're marching in the right direction. Thank you.

Edited November 5, 2020 by IronMike

[QuiGon]

Dear all, ED is watching this thread as well, however what we'd need would be short tracks of the several issues. If anyone of you could post short tracks (as short as possible), it would help a lot! Thank you!

 

I will be able to run a private test session on the weekend with a few buddies. I hope it's not an issue for testing, if one of the participants (probably the RIO of the launching Tomcat) is also the server host?

 

 

To answer above questions: 1. TWS mid course guidance will not trigger a launch warning, when it goes active it will trigger a MSL launch warning. 2. PH ACT launches the missile active off the rail, I am not sure whether it gets DL updates from the AWG-9 at this point anymore, I need to ask Naquaii or Gyro for that. My guess would be no.

 

Good to know, thanks!