[WAD] 1271.1-Amraam NEZ shots are occuring around 12nm

[BDukes]

Using NEZ Amraam D and C7 shots are occuring around 12-13nm. Not sure if that is correct.

Scenarios attached.

[KilianJay]

There seems to be a bug where at least all AAM and SAM I tested use up their fuel almost instantly since the last beta.
I think your problem is caused by the same issue.

[Dimitris]

There seems to be a bug where at least all AAM and SAM I tested use up their fuel almost instantly since the last beta.
I think your problem is caused by the same issue.

As we explained on the release notes for the "Tiny" public beta:

On missiles that use this model, the "fuel bar" indicator now represents only the remaining boost-sustain fuel, NOT to the total remaining energy. After burnout, the fuel bar is removed and the weapon will coast until it reaches its stall speed.

The fact that the burn duration on most tactical boost-coast weapons is only a few seconds is WAD.

[boogabooga]

Please see this post
https://www.matrixgames.com/forums/view ... 1#p5017141

The 12-13nm NEZ actually makes sense and is consistent with flight sims.

[bsq]

There seems to be a bug where at least all AAM and SAM I tested use up their fuel almost instantly since the last beta.
I think your problem is caused by the same issue.

As we explained on the release notes for the "Tiny" public beta:

On missiles that use this model, the "fuel bar" indicator now represents only the remaining boost-sustain fuel, NOT to the total remaining energy. After burnout, the fuel bar is removed and the weapon will coast until it reaches its stall speed.

The fact that the burn duration on most tactical boost-coast weapons is only a few seconds is WAD.

41nm to stall an AIM-120D with a database range of 86nm, less than half RMax.

Conceding that the motor burn is correct, thats how solid fuel works, then something else is not if RMax cannot be acheived on a straight line run. I calculated the deceleration and it was in the order of 2G, which given the missile was diving at the time seems odd. The missile in question was lofted to around 48kft, and was in a shallow dive to a target at 36kft (co-altitude with the firing platform). The missile 'fell out of the sky' at 41nm. The deceleration noted was calculated during a straightline portion of the run in, no manouevring, still a head on shot (the target had not, at that point, detected the shot).

[LetMePickThat]

41nm to stall an AIM-120D with a database range of 86nm, less than half RMax.

Conceding that the motor burn is correct, thats how solid fuel works, then something else is not if RMax cannot be acheived on a straight line run. I calculated the deceleration and it was in the order of 2G, which given the missile was diving at the time seems odd. The missile in question was lofted to around 48kft, and was in a shallow dive to a target at 36kft (co-altitude with the firing platform). The missile 'fell out of the sky' at 41nm. The deceleration noted was calculated during a straightline portion of the run in, no manouevring, still a head on shot (the target had not, at that point, detected the shot).

What was the separation speed ?

2G is actually quite close to what I would expect for a fast-burner AAM. See for instance this chart for the 530D model I worked on for another sim. This is a similar shot to yours, with a launch from FL400, loft to FL500 then dive to target. The cutoff speed was Mach 4.52, and that the impact speed was Mach 2.65 (give or take), which gives us a delta of approximately 555m/s (assuming an average speed of sound of 295m/s, which is reasonable between FL400 and FL500). The cutoff occurred at T+11, and impact at T-45. The average decceleration was thus 16.3m/s, or 1.7G. Keeping in mind that the 530D was specifically optimized for low drag at high altitude, at the expense of maneuverability, I'd say that a 2G deceleration for an AMRAAM with midbody, all moving (i.e drag-generating) control surfaces is in the right ballpark.



Similarly, here is the chart for the R-27ER missile, which shows a decceleration of around 2.24G when fired from an altitude of 15 000m (1100 m/s to 700 m/s in 50s, i.e approx. 22m/s^2). The higher decceleration is caused by the lack of loft on the R-27ER.



Consider the fact that for the 530D, the best my model could achieve using credible, non-perfect engagement conditions was 17 nm (31 km), versus an advertised max range of "more than 25nm". Since we don't know how the Rmax on the 120D was calculated, it's hard to make a conclusion as whether your 41nm is correct or not without extensive testing. What's the theoretical range when fired from an F-22 doing Mach 2.2 at FL650 for instance ? I personally find it dubious in the first place that the 120D could reach such an Rmax using a regular dual-pulse solid fuel engine, when other missiles need to either use exotic propulsion systems (Meteor) or be considerably heavier (R-33, AIM-54) to achieve similar ranges, but that's just me.

[thewood1]

Were you one of the contributors to that paper for DCS on AAM performance?

[LetMePickThat]

Were you one of the contributors to that paper for DCS on AAM performance?

If you're referring to the very good paper on the AIM-120C5, no. I did however write a paper on the 530D for Razbam, though some parts could not be made public because the M2000 is pretty much still in development.

[BDukes]

Please see this post
https://www.matrixgames.com/forums/view ... 1#p5017141

The 12-13nm NEZ actually makes sense and is consistent with flight sims.

Perfect. I wasn't understanding what NEZ really was and not sure where somebody would use this in the game.

What I'm looking for is a shot that won't get turned and burned each time. That occurs with the default WRA for most aircraft weapons.

Mike

[LetMePickThat]

Please see this post
https://www.matrixgames.com/forums/view ... 1#p5017141

The 12-13nm NEZ actually makes sense and is consistent with flight sims.

Perfect. I wasn't understanding what NEZ really was and not sure where somebody would use this in the game.

What I'm looking for is a shot that won't get turned and burned each time. That occurs with the default WRA for most aircraft weapons.

Mike

WRAs are optimistic by default. Tailoring them to specific missions is one of the most demading task in CMO, imho, and one of the critical step towards success. Maybe mission type specific rules could be used (i.e WRA optimistic for CAP/air interdiction missions to maintain separation, while other mission types could afford to wait more before launching?).

[Dimitris]

The AIM-120C-5 paper referenced: http://www.zaretto.com/sites/zaretto.co ... t-rev2.pdf

[BDukes]

Please see this post
https://www.matrixgames.com/forums/view ... 1#p5017141

The 12-13nm NEZ actually makes sense and is consistent with flight sims.

Perfect. I wasn't understanding what NEZ really was and not sure where somebody would use this in the game.

What I'm looking for is a shot that won't get turned and burned each time. That occurs with the default WRA for most aircraft weapons.

Mike

WRAs are optimistic by default. Tailoring them to specific missions is one of the most demading task in CMO, imho, and one of the critical step towards success. Maybe mission type specific rules could be used (i.e WRA optimistic for CAP/air interdiction missions to maintain separation, while other mission types could afford to wait more before launching?).

Yeah I'm looking for a more successful choice than the default which is to fail. Even if you're on the side of this default configuration the AI's WRA will need to be adjusted or it'll be a crummy opponent.

I assume pilots and militaries have best practices as to when they shoot that is based on math and experience. Maybe this should be the default setting's goal?

Mike

[LetMePickThat]

Yeah I'm looking for a more successful choice than the default which is to fail. Even if you're on the side of this default configuration the AI's WRA will need to be adjusted or it'll be a crummy opponent.

To me, setting up good WRAs is your job as a commander. It should also be the mission designer's job to do the same for the opponent.

I assume pilots and militaries have best practices as to when they shoot that is based on math and experience. Maybe this should be the default setting's goal?

The problem with that is that IRL, this dynamically changes based on the TACSI. For instance, two F-16C facing two J-10C might have a very conservative approach to weapon employment, and wait as late as possible to maximise Pk because they only have 4 MRM (assuming two bags, two 120C/D and two 9X). Now, the TACSI changes because an F-22 or another F-16 flight is close by. The pilots might reevaluate their tactic and go for the very long range, low-Pk shots to provide an opening for the buddies to engage at NEZ range, while the bandits can't replicate because they went defensive to avoid the first salvo. That's very hard to model because dynamically changing the behaviour of a rule-base AI based on variables such as distance-to-nearest friend is complex. Not to mention that the WR distance is also be dictated by other factors, such as the presence of an allied AWACS (or ground troops, or a ship) that needs to be defended (you'd go for longer ranged shots to keep the ennemy at bay, no need to risk them firing at the AWACS by waiting until NEZ is obtained).

[AceOfSpadeszzzzzz]

So IMO I think the motor burn time is actually WAD, the question is are we generating the correct loft plan for the missile - if you try to fire a missile at a target that's far away and is flying away from you the missile actually gets higher terminal speed when approaching the target, because the missile goes higher and stays at high altitude for a longer time. I think missiles in CMO descend toward the target earlier than that in those combat sims. Also seems that the missile is pulling too hard when the target is doing the maneuvers. Another thing is that the planes in CMO don't lose speed when making a hard turn and accelerate much faster than that in those flight sims like DCS or BMS. That's why you don't have those 20 25ish miles of NEZ in DCS or BMS.

[thewood1]

There are ways to change WRA dynamically with ROE/WRA templates and with lua. I have played with them in the recent past. Not sure its worth the effort players just jonesing to see their favorite side/unit go all hero. But for more flexibility as a scenario designer, its a great tool.

[thewood1]

"20 25ish miles of NEZ in DCS or BMS"

Does DCS have the 120D?

[thewood1]

Also, if you read up on some of the limited engagements in the Balkans police action/conflict, there were shoot downs, but a lot of misses against small maneuvering targets also.

[BDukes]

Yeah I'm looking for a more successful choice than the default which is to fail. Even if you're on the side of this default configuration the AI's WRA will need to be adjusted or it'll be a crummy opponent.

To me, setting up good WRAs is your job as a commander. It should also be the mission designer's job to do the same for the opponent.

Yeppers.

I assume pilots and militaries have best practices as to when they shoot that is based on math and experience. Maybe this should be the default setting's goal?

The problem with that is that IRL, this dynamically changes based on the TACSI. For instance, two F-16C facing two J-10C might have a very conservative approach to weapon employment, and wait as late as possible to maximise Pk because they only have 4 MRM (assuming two bags, two 120C/D and two 9X). Now, the TACSI changes because an F-22 or another F-16 flight is close by. The pilots might reevaluate their tactic and go for the very long range, low-Pk shots to provide an opening for the buddies to engage at NEZ range, while the bandits can't replicate because they went defensive to avoid the first salvo. That's very hard to model because dynamically changing the behaviour of a rule-base AI based on variables such as distance-to-nearest friend is complex. Not to mention that the WR distance is also be dictated by other factors, such as the presence of an allied AWACS (or ground troops, or a ship) that needs to be defended (you'd go for longer ranged shots to keep the ennemy at bay, no need to risk them firing at the AWACS by waiting until NEZ is obtained).

I'm one of CMANOs founding four and have published and sold lots of scenarios, a battleset and one game. I worked for AGSI and the Harpoons in the past as well. I definitely understand the complexity of the issue, but playability is important too. I think the whole rationale for WRAs on day one is so players who don't get the detail-level stuff can make reasonable choices.

Anyways just asking. I'm not heavily invested in this as I can just fix myself.

Mike

[AceOfSpadeszzzzzz]

"20 25ish miles of NEZ in DCS or BMS"

Does DCS have the 120D?

Sorry I mean C 5

[AceOfSpadeszzzzzz]

Also, if you read up on some of the limited engagements in the Balkans police action/conflict, there were shoot downs, but a lot of misses against small maneuvering targets also.

I don't think that's very related to the NEZ. If you take a look at the hit probability calculation in game, you will see that even inside the NEZ against non-maneuvering targets, the chance to hit is still not 100%, this scenario is already modeled in game IMO. Also the missile could be malfunctioning.