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AIM-54 Hotfix PSA and Feedback Thread - Guided Discussion


IronMike

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Alrighty, so today, I decided to do some testing with the Phoenix, but not what everyone else is testing.

I noticed a long time ago that it seemed like the Phoenix TWS Trajectory doesn't make a lot of sense to me.  What I noticed is it would launch and go into a pure pursuit in TWS.  This, isn't a real big issue, except that it isn't actually calculating the pursuit angle correctly and actually makes an arc to the target rather than flying to the computed impact point.  This was contributing to the "self notching" behavior of the missile.  So here is my test parameters:

Map: Mariana's over the ocean pointing towards nothing but ocean

Launch Aircraft:
F-14B, ~33k Feet, Mach 1.21 AIM-54C, Course: Due North

Target Aircraft:
Su-33, ~36k feet, Mach 0.75, Course: ~210 degrees, Set to Not react (so no maneuvering, changing speeds, etc)

Distance at launch was 67.1nmi with the above parameters.

Here is a picture of the course the AIM-54 took  to guide in on the Su-33:

Test1.PNG

See the left hand arc in the trajectory?  Seems counter intuitive.  The Su-33 is not changing speed, not changing heading, nor changing altitude.  It's constant.  To me, the arc does not make logical sense.  Why would this missile not leave the aircraft and turn to the "perfect" intercept angle to impact the target without making any other turns.  Again, the target is not maneuvering (no altitude or heading changes) or changing speed.  The impact point should be fixed in space such that the missile goes active without maneuvering laterally beyond the initial turn to the intercept point.  I should point out this problem ALSO exists in PD-STT at these same ranges.  I'd also point out, that the computed impact point, FOR THIS SCENARIO, should not change at all from the initial one because the aircraft is not maneuvering or changing speed.  With that in mind, I don't think the TWS track refresh rate matters for this particular case.

Because I'm slightly crazy, I repeated this test with the AIM-120C and the F-15. The AIM-120C's lead angle on a ~45nmi shot is far closer to a straight line, but it still makes the turn.  
test2.PNG

I also performed these tests with the F-16C (33k feet, Mach 1.56) with both the AIM-120B and the AIM-120C but the shorter launch ranges (~20nmi) showed a nearly straight line to impact, which makes sense given the time of flight of the missile.

I fully realize there is a "balance" between the missile making its initial turn and energy, but this seems like that computed impact point is very wrong for the AIM54 and it is computing an impact point which is closer to the target than it should be.  The end result is a missile which is easier to notch (because it's "behind" the pursuit curve). 

Hopefully Heatblur or ED can shed some light on the guidance issues seen here!

F-14AIM54Test1.acmi F-15AIM120CTest1.acmi MissileGuidanceTest2.trk MissileGuidanceTestF14AIM54C.trk MissileGuidanceTestF15TWS120C.trk MissileGuidanceTestF15TWS120C2.trk


Edited by Whiskey11
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30 minutes ago, Whiskey11 said:

Alrighty, so today, I decided to do some testing with the Phoenix, but not what everyone else is testing.

I noticed a long time ago that it seemed like the Phoenix TWS Trajectory doesn't make a lot of sense to me.  What I noticed is it would launch and go into a pure pursuit in TWS.  This, isn't a real big issue, except that it isn't actually calculating the pursuit angle correctly and actually makes an arc to the target rather than flying to the computed impact point.  This was contributing to the "self notching" behavior of the missile.  So here is my test parameters:

Map: Mariana's over the ocean pointing towards nothing but ocean

Launch Aircraft:
F-14B, ~33k Feet, Mach 1.21 AIM-54C, Course: Due North

Target Aircraft:
Su-33, ~36k feet, Mach 0.75, Course: ~210 degrees, Set to Not react (so no maneuvering, changing speeds, etc)

Distance at launch was 67.1nmi with the above parameters.

Here is a picture of the course the AIM-54 took  to guide in on the Su-33:

Test1.PNG

See the left hand arc in the trajectory?  Seems counter intuitive.  The Su-33 is not changing speed, not changing heading, nor changing altitude.  It's constant.  To me, the arc does not make logical sense.  Why would this missile not leave the aircraft and turn to the "perfect" intercept angle to impact the target without making any other turns.  Again, the target is not maneuvering (no altitude or heading changes) or changing speed.  The impact point should be fixed in space such that the missile goes active without maneuvering laterally beyond the initial turn to the intercept point.  I should point out this problem ALSO exists in PD-STT at these same ranges.  I'd also point out, that the computed impact point, FOR THIS SCENARIO, should not change at all from the initial one because the aircraft is not maneuvering or changing speed.  With that in mind, I don't think the TWS track refresh rate matters for this particular case.

Because I'm slightly crazy, I repeated this test with the AIM-120C and the F-15. The AIM-120C's lead angle on a ~45nmi shot is far closer to a straight line, but it still makes the turn.  
test2.PNG

I also performed these tests with the F-16C (33k feet, Mach 1.56) with both the AIM-120B and the AIM-120C but the shorter launch ranges (~20nmi) showed a nearly straight line to impact, which makes sense given the time of flight of the missile.

I fully realize there is a "balance" between the missile making its initial turn and energy, but this seems like that computed impact point is very wrong for the AIM54 and it is computing an impact point which is closer to the target than it should be.  The end result is a missile which is easier to notch (because it's "behind" the pursuit curve). 

Hopefully Heatblur or ED can shed some light on the guidance issues seen here!

F-14AIM54Test1.acmi 117.08 kB · 0 downloads F-15AIM120CTest1.acmi 136.88 kB · 0 downloads MissileGuidanceTest2.trk 1.21 MB · 0 downloads MissileGuidanceTestF14AIM54C.trk 678.31 kB · 0 downloads MissileGuidanceTestF15TWS120C.trk 880.74 kB · 0 downloads MissileGuidanceTestF15TWS120C2.trk 555.22 kB · 0 downloads

 

I posted about the Phoenix falling into a almost a lagging pursuit as well. Not an energy optimising arc compared to the AMRAAM. 

In addition, you should check out the vertical trajectory for long range shots. For many sub-40 mile shots (Angels 30), the trajectory remains a little too flat. So it looks to me the missile burns fuel but doesn't get to maximise it's altitude. 

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On a slight tangent, ED-developed modules (Hornet, Viper, Warthog and probably others) are still getting active-off-the-rail RWR warnings for 54s fired in TWS, at least from AI.  I haven't been able to test with player piloted Tomcats yet.  I'd be genuinely surprised if it wasn't true for players and probably explains a bit of the mixed results that people seem to be having in PvP.  I've reported it and it's being investigated, but worth being aware of in the meantime.

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@Whiskey11

 

This seems really weird, saw similar behaviour on the Discord, post by @Noctrach about the random 90 degree ice-cream turn.

 

Looking closely the 54 does a similar thing there, instead of a clean intercept it looks like a detour / longer pursuit for some reason. Leading to excessive energy bleed since it needs to compensate for the less than optimal route to target. 


Edited by Comstedt86
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2 hours ago, Comstedt86 said:


@Whiskey11

 

This seems really weird, saw similar behaviour on the Discord, post by @Noctrach about the random 90 degree ice-cream turn.

 

Looking closely the 54 does a similar thing there, instead of a clean intercept it looks like a detour / longer pursuit for some reason. Leading to excessive energy bleed since it needs to compensate for the less than optimal route to target. 

 

This is different tbh. The issue Whiskey11 describes is that the Phoenix goes pure-ish pursuit off the rail rather than flying an intercept curve.

The effect of this is that it will waste a lot of energy constantly correcting for changing target aspect. It also means centering the T on a cranking target is pointless, because the missile will steer to turn towards the target rather than flying straight to predicted intercept point. So a shot with a properly centered T will have less energy due to having the missile correct heading during the initial launch phase. You're essentially shooting off boresight...

What you saw on my images is just ED's fucked up interpretation of how a last second notch affects guidance. Possibly even a chaff interaction where it tries to do a 180 to get chaff that was released behind the missile when it no longer has the energy to do so. Not a Heatblur problem.


Edited by Noctrach
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8 hours ago, Whiskey11 said:

Alrighty, so today, I decided to do some testing with the Phoenix, but not what everyone else is testing.

I noticed a long time ago that it seemed like the Phoenix TWS Trajectory doesn't make a lot of sense to me.  What I noticed is it would launch and go into a pure pursuit in TWS.  This, isn't a real big issue, except that it isn't actually calculating the pursuit angle correctly and actually makes an arc to the target rather than flying to the computed impact point.  This was contributing to the "self notching" behavior of the missile.  So here is my test parameters:

Map: Mariana's over the ocean pointing towards nothing but ocean

Launch Aircraft:
F-14B, ~33k Feet, Mach 1.21 AIM-54C, Course: Due North

Target Aircraft:
Su-33, ~36k feet, Mach 0.75, Course: ~210 degrees, Set to Not react (so no maneuvering, changing speeds, etc)

Distance at launch was 67.1nmi with the above parameters.

Here is a picture of the course the AIM-54 took  to guide in on the Su-33:

Test1.PNG

See the left hand arc in the trajectory?  Seems counter intuitive.  The Su-33 is not changing speed, not changing heading, nor changing altitude.  It's constant.  To me, the arc does not make logical sense.  Why would this missile not leave the aircraft and turn to the "perfect" intercept angle to impact the target without making any other turns.  Again, the target is not maneuvering (no altitude or heading changes) or changing speed.  The impact point should be fixed in space such that the missile goes active without maneuvering laterally beyond the initial turn to the intercept point.  I should point out this problem ALSO exists in PD-STT at these same ranges.  I'd also point out, that the computed impact point, FOR THIS SCENARIO, should not change at all from the initial one because the aircraft is not maneuvering or changing speed.  With that in mind, I don't think the TWS track refresh rate matters for this particular case.

Because I'm slightly crazy, I repeated this test with the AIM-120C and the F-15. The AIM-120C's lead angle on a ~45nmi shot is far closer to a straight line, but it still makes the turn.  
test2.PNG

I also performed these tests with the F-16C (33k feet, Mach 1.56) with both the AIM-120B and the AIM-120C but the shorter launch ranges (~20nmi) showed a nearly straight line to impact, which makes sense given the time of flight of the missile.

I fully realize there is a "balance" between the missile making its initial turn and energy, but this seems like that computed impact point is very wrong for the AIM54 and it is computing an impact point which is closer to the target than it should be.  The end result is a missile which is easier to notch (because it's "behind" the pursuit curve). 

Hopefully Heatblur or ED can shed some light on the guidance issues seen here!

F-14AIM54Test1.acmi 117.08 kB · 1 download F-15AIM120CTest1.acmi 136.88 kB · 1 download MissileGuidanceTest2.trk 1.21 MB · 1 download MissileGuidanceTestF14AIM54C.trk 678.31 kB · 1 download MissileGuidanceTestF15TWS120C.trk 880.74 kB · 1 download MissileGuidanceTestF15TWS120C2.trk 555.22 kB · 1 download

 

This problem is especially noticeable against high speed targets that are almost beaming at longer ranges. That will cause the AIM-54 to just lag behind and the target doesn't even have to put that much effort in defending the missile.

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8 hours ago, nighthawk2174 said:

@IronMikeIs the missile fully on the new ED FM?  Also are motor on drag reductions a thing?

No, it is still on the old missile FM. If by the second you mean plume effects, then no. From my understanding, and that is limited, they are quite complicated to do and we might look into them at a later point.

As for the other questions asked: induced drag is a consequence of lift and created by airfoils passing through the air, for example wings, to put it very simple, which was set too high. This does not affect the straightline performance, the CFD still matches, but harder turns for example will make it lose slightly less energy. The difference is not very big, but it helps a bit with guidance corrections, etc.

The TWS AIM54 giving RWR warnings on launch is an AI issue and if I remember correctly isolated to FC3 modules.

As for pure vs lead - I need to ask if related, however in the old API the missile cannot guide towards a point in space, and needs an object to guide on. This poses an issue with for example guiding on extrapolated tracks. However I am not quite sure if it is the reason for not leading a target.

I, too, noticed the reported hard pulls within terminal guidance, however these seem to be a combination of a) chaff/notch and b) low energy state of the missile. Unfortunately this is likely not something we can influence from our side, although the change introduced by ED should help with that, and generally with guidance corrections. It looks more like a weird overreaction to chaff and notching to me currently, which, in most of the situations where I encountered it, without the overreaction would still likely lead to a missile missing its target.


Overall the guidance should be more stable now and the self-defeating attitude of cutting into its own energy, by large, pre-mature overcorrections should be less now. While also maintaining slightly more energy through needed corrections.

I need to look into the extrapolated track issue, during testing this seemed fine.


 

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I will add that the predicted impact point cannot be constant because the kinematics of the missile are always changing.  As the speed of the missile changes it changes the calculation.  I don't know if an older missile like the Phoenix can compensate for that to minimize the drift, but at terminal when it is often slowing way down there is nothing to be done.  

 

This is something I have experienced with on my home-made missile performance simulator.


Edited by Spurts
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3 hours ago, Noctrach said:

This is different tbh. The issue Whiskey11 describes is that the Phoenix goes pure-ish pursuit off the rail rather than flying an intercept curve.

The effect of this is that it will waste a lot of energy constantly correcting for changing target aspect. It also means centering the T on a cranking target is pointless, because the missile will steer to turn towards the target rather than flying straight to predicted intercept point. So a shot with a properly centered T will have less energy due to having the missile correct heading during the initial launch phase. You're essentially shooting off boresight...

What you saw on my images is just ED's fucked up interpretation of how a last second notch affects guidance. Possibly even a chaff interaction where it tries to do a 180 to get chaff that was released behind the missile when it no longer has the energy to do so. Not a Heatblur problem.

 

I mean up until the 90 degree turn the intercept looks weird as well. 

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The AIM-54A-60 is a beast again. At 40k you can bag ace level AI F-16Cs from 70 nm without even assisting the loft, missiles impacting at ~Mach 2. The new AI has actually made the them worse in some ways. Since they no longer start evading until the pitbull warning, it's too late for them. The same shot was only available at about 50 nm in the previous patch in my testing. Whatever induced drag changes were made has made a large difference IMO, not a subtle one.

I'm also seeing some weird behavior VS F-16s though. Especially with close range active off the rail shots. The AI can break the lock with a simple aileron roll. I think as soon as they are inverted the lock is broken. Virtually no aspect change needed. More testing needed.

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40 minutes ago, Callsign JoNay said:

The AIM-54A-60 is a beast again. At 40k you can bag ace level AI F-16Cs from 70 nm without even assisting the loft, missiles impacting at ~Mach 2. The new AI has actually made the them worse in some ways. Since they no longer start evading until the pitbull warning, it's too late for them. The same shot was only available at about 50 nm in the previous patch in my testing. Whatever induced drag changes were made has made a large difference IMO, not a subtle one.

I'm also seeing some weird behavior VS F-16s though. Especially with close range active off the rail shots. The AI can break the lock with a simple aileron roll. I think as soon as they are inverted the lock is broken. Virtually no aspect change needed. More testing needed.

Well I hope the PvP community will realise that they cannot afford to fly a straight line intercept against a Tomcat and expect to walk away from it. Its not the missiles being Op. Even at the get go.

Likewise, never fly a straight line intercept against an adversary with forward quarter long-medium range missiles.

 

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2 hours ago, IronMike said:



As for pure vs lead - I need to ask if related, however in the old API the missile cannot guide towards a point in space, and needs an object to guide on. This poses an issue with for example guiding on extrapolated tracks. However I am not quite sure if it is the reason for not leading a target.


 

How does the new API work then? Does it create an object for the missile to guide on?

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6 hours ago, IronMike said:

As for pure vs lead - I need to ask if related, however in the old API the missile cannot guide towards a point in space, and needs an object to guide on. This poses an issue with for example guiding on extrapolated tracks. However I am not quite sure if it is the reason for not leading a target.

I, too, noticed the reported hard pulls within terminal guidance, however these seem to be a combination of a) chaff/notch and b) low energy state of the missile. Unfortunately this is likely not something we can influence from our side, although the change introduced by ED should help with that, and generally with guidance corrections. It looks more like a weird overreaction to chaff and notching to me currently, which, in most of the situations where I encountered it, without the overreaction would still likely lead to a missile missing its target.


Overall the guidance should be more stable now and the self-defeating attitude of cutting into its own energy, by large, pre-mature overcorrections should be less now. While also maintaining slightly more energy through needed corrections.

I need to look into the extrapolated track issue, during testing this seemed fine.

I wouldn't think it would necessarily need to guide towards a point in space (although I imagine that is how the missile does it IRL, with the AWG-9 updating that point in space) vs constantly guiding on the target.  I posted the extreme case above (with tracks and Tacview files) where the target is not chaffing, flaring, maneuvering or changing speed.  The impact point, even if guiding on the target, should never change, and thus the missile itself, should not be maneuvering, let alone the gentle arc it takes after launch.  The target launched on in my test was not an extrapolated track either.  Constant TWS track from before launch to launch.  

When I tested it in PD-STT, the behavior was the same.  The ONE change between the two was the difference in the steering T... on the TWS shot, the steering T was to the right of my flight path.  In PD-STT it was nearly centered.  This did NOT change the missile's behavior much... Actually, in PD-STT it had a more aggressive arc to the target than the TWS shot.

Because I knew the AIM-54 is in the weird hybrid zone between Old and New API's, I wanted to test the AIM-120C in the same scenario.  The results were better, but the range was less (~45-55nmi shots).  It still had a gentle arc on a non chaffing/flaring, maneuvering or changing speed target.  That at least suggests the guidance issue is present in the AIM-120C.  I'm NOT sure if this is an issue with how the game handles missiles or not.  What I mean is, I don't know if guidance is being done by the aircraft and the missile is commanded to move (as it would be IRL) or if it is doing these guidance things on their own (the missile knows where it is).  If it's the former, than the issue is in the F-14.  If it's the latter, it's ED, since they have control of the missiles in game.

Quote

I will add that the predicted impact point cannot be constant because the kinematics of the missile are always changing.  As the speed of the missile changes it changes the calculation.  I don't know if an older missile like the Phoenix can compensate for that to minimize the drift, but at terminal when it is often slowing way down there is nothing to be done.  

 

This is something I have experienced with on my home-made missile performance simulator.

I'm pretty confident, the ballistic path of these missiles was well studied and accounted for.... and even if it was the case it wasn't, the arc would be the OPPOSITE of what we see right now.  Specifically, it would be overshooting the impact point (assuming less losses than reality) and curving towards a more straight impact vs now where it is UNDERSHOOTING the target and having to play catch up, effectively self notching.

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6 hours ago, IronMike said:

No, it is still on the old missile FM. If by the second you mean plume effects, then no. From my understanding, and that is limited, they are quite complicated to do and we might look into them at a later point.

As for the other questions asked: induced drag is a consequence of lift and created by airfoils passing through the air, for example wings, to put it very simple, which was set too high. This does not affect the straightline performance, the CFD still matches, but harder turns for example will make it lose slightly less energy. The difference is not very big, but it helps a bit with guidance corrections, etc.

The TWS AIM54 giving RWR warnings on launch is an AI issue and if I remember correctly isolated to FC3 modules.

As for pure vs lead - I need to ask if related, however in the old API the missile cannot guide towards a point in space, and needs an object to guide on. This poses an issue with for example guiding on extrapolated tracks. However I am not quite sure if it is the reason for not leading a target.

I, too, noticed the reported hard pulls within terminal guidance, however these seem to be a combination of a) chaff/notch and b) low energy state of the missile. Unfortunately this is likely not something we can influence from our side, although the change introduced by ED should help with that, and generally with guidance corrections. It looks more like a weird overreaction to chaff and notching to me currently, which, in most of the situations where I encountered it, without the overreaction would still likely lead to a missile missing its target.


Overall the guidance should be more stable now and the self-defeating attitude of cutting into its own energy, by large, pre-mature overcorrections should be less now. While also maintaining slightly more energy through needed corrections.

I need to look into the extrapolated track issue, during testing this seemed fine.


 

I think that implementing them will be important.  From aim-7 data it can be as much as 15+% reduction in drag.  I really hope you guys do add these effects.  For the aim-54 this would be super important due to the low thrust but high burn time.

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1 hour ago, Whiskey11 said:

I'm pretty confident, the ballistic path of these missiles was well studied and accounted for.... and even if it was the case it wasn't, the arc would be the OPPOSITE of what we see right now.  Specifically, it would be overshooting the impact point (assuming less losses than reality) and curving towards a more straight impact vs now where it is UNDERSHOOTING the target and having to play catch up, effectively self notching.

It's not the ballistics, it's the lateral.  As the missile slows down it will take more time to reach the target point, which means the target will move farther down it's flight path before interception, this makes a new impact point, which makes the missile aim left at the new impact point, which slows it down more, etc etc etc.  Look back at the speed of the missile at the various points of it's curvature.  Does it turn harder and harder as it slows more and more?

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12 minutes ago, Spurts said:

It's not the ballistics, it's the lateral.  As the missile slows down it will take more time to reach the target point, which means the target will move farther down it's flight path before interception, this makes a new impact point, which makes the missile aim left at the new impact point, which slows it down more, etc etc etc.  Look back at the speed of the missile at the various points of it's curvature.  Does it turn harder and harder as it slows more and more?

This doesn't make a lot of intuitive sense to me because the mid-course guidance is given by the AWG-9 which bases it on a precalculated time to impact, not on missile's real speed. That's not to say that DCS doesn't use missile speed. Who knows...

The other thing is that this would not lead to the missile doing a turn-to-target as its first action after coming off the rails. I totally expect some curvature like this to happen as the missile goes into active guidance, since it is trying to find an optimum between intercept and energy conversation. But if the target doesn't change aspect, the missile trajectory should be pretty much straight since it hasn't to deviate at all from the predicted parameters.

Current guidance has the missile spoil its own collision intercept trajectory by turning nose-on after launch and then compensating all the way to impact.

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5 hours ago, Spurts said:

It's not the ballistics, it's the lateral.  As the missile slows down it will take more time to reach the target point, which means the target will move farther down it's flight path before interception, this makes a new impact point, which makes the missile aim left at the new impact point, which slows it down more, etc etc etc.  Look back at the speed of the missile at the various points of it's curvature.  Does it turn harder and harder as it slows more and more?

Ballistics includes lateral changes as well as vertical and longitudinal changes... it's the study of the motion of projectiles in flight.  

Nitpicking aside, I'm pretty sure this was fairly well studied, and I'd be shocked if the AWG-9 couldn't perform at least rudimentary calculations for this in near real time given how much a small error like that would make a difference at the massive ranges of the AIM-54's expected flight profiles.  Again, the whole premise is for the AWG-9 to put the missile in a place where when it goes active, the seeker is pointed more or less at the target.  Ignoring the effects of drag in this equation would be a huge mistake and it'd never hit the intended target.

  

4 hours ago, AH_Solid_Snake said:

Theres also the simple fact that the only input we’ve had on this topic from Victory205 was “center the T, precisely”

If the missile immediately makes a hard turn away from the steering cue then either the symbology or missile is doing something wrong.


There is that too... if you download the tacview, the impact point for this shot puts the Su-33 basically dead ahead of the F-14... if the computed impact point at launch was correct, the Missile would have came off effectively dead ahead, but it didn't, it came off and went right.  I posted in my response to IronMike that in TWS the steering T was pointed to the right, but was dead center in PD-STT.  The missile behavior was essentially the same (see the track files).  So if centering the T was the issue, I'd expect the PD-STT shot to have been a straighter path... and it actually wasn't any straighter (arguably the impact angle was worse), hence my post about the guidance issues! 😉


Edited by Whiskey11
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I'm going to dump my graphs here:

With my extensive testing, I've come to the conclusion that I already knew: the AIM-54s are faster this patch. 

Test parameters: Launched at Mach 1.0 at 40000 ft (active pause on) at an ace AI target flying Mach 0.85 at 30000 ft hot aspect in TWS with target size at small. All utilizing track files (when comparing the new and old at the same distance) for the most accuracy in terms of distance fired and what the AI does to defend. I used the OB 2.7.15.25026 as the version I conducted my testing it, I only reverted the Weapons.lua file to the older OB 2.7.14.24228 patch in order to test for the old drag numbers. This does mean that the improvement to the AIM-54 guidance effects the values I have here. A discrepancy I had noticed is that the AI will defend the missile at 10nms even though its supposed to go active at around 6nms when using Target Size Small.

 

Actual Conclusion: AIM-54s overall go faster and because of that speed, they loft to a lower altitude while also maintaining a higher speed at those lower altitudes. The speed increase is most effective at long range shots as the lofting flight profile has the most induced drag and as you get closer, the loft gets less and less dramatic which results in less effects from the new reduced induced drag. It is important to note that the Mk47 motor variants have rather poor performance against maneuvering targets. 

 

Graphs:

AIM-54A-Mk60

Spoiler

AIM-54A-Mk60_30nms_Same_Track_Launched_a

 

AIM-54A-Mk60_50nms_Same_Track_Launched_a

 

AIM-54A-Mk60_70nms_Same_Track_Launched_a

 

AIM-54A-Mk60_90nms_Same_Track_Launched_a

 

AIM-54A-Mk47

Spoiler

 

AIM-54A-Mk47_30nms_Same_Track_Launched_a

 

AIM-54A-Mk47_50nms_Same_Track_Launched_a

 

AIM-54A-Mk47_70nms_Same_Track_Launched_a

 

AIM-54A-Mk47_90nms_Same_Track_Launched_a

 

AIM-54C-Mk47

Spoiler

 

AIM-54C-Mk47_30nms_Same_Track_Launched_a

 

AIM-54C-Mk47_50nms_Same_Track_Launched_a

 

AIM-54C-Mk47_70nms_Same_Track_Launched_a

 

AIM-54C-Mk47_90nms_Same_Track_Launched_a

 

Bonus AIM-54A-Mk60 Graph. This includes the Weapons.lua file from OB 2.7.3.8494 this means its before the drag values were modified to match the CFD values found in the whitepaper. It's also very easy to notice the time of the flight where the missile had took a hard turn (4.9Gs max) in order to align itself before going active.

Spoiler

AIM-54A-Mk60_90nms_Same_Track_Launched_a

 


Edited by DSplayer
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-Tinkerer, Certified F-14 and AIM-54 Nut | Discord: @dsplayer

Setup: i7-8700k, GTX 1080 Ti, 32GB 3066Mhz, Lots of Storage, Saitek/Logitech X56 HOTAS, TrackIR + TrackClipPro
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Mods I've Made: F-14 Factory Clean Cockpit Mod | Modern F-14 Weapons Mod | Iranian F-14 Weapons Pack | F-14B Nozzle Percentage Mod + Label Fix | AIM-23 Hawk Mod for F-14 

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Just wanted to share this pretty crazy clip we saw this weekend on our wing's Saturday night main event. An F-14A was able to kill a cold aspect F-16C from 45nm. The F-16 was doing 0.9 Mach at 40k at the time of the missile launch, but continued to accelerate all the way up to Mach 1.4, and still got nailed. I'm sure the F-16 could've defeated the missile if he dove to a lower altitude, but he assumed he was more than safe from that range and speed. I estimate the missile probably travelled about 70 miles and was still doing Mach 2 at impact. AIM-54A-60.

Edit/Add: I forgot to mention the missile got up to Mach 5.6 btw.

Kill VS a Cold Aspect F-16 40 nm.txt.acmi


Edited by Callsign JoNay
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One thing I would like to mention for future guidance reference is that currently look-down shots just have the phoenix doing a straight beeline to the target.

There's some pros and cons to this... slightly faster flight path, slightly shallower angle (bit less notch-sensitive), but it also has to do a lot of energy-intensive correcting in the thick air. I'm not sure which is the favourable geometry tbh.

Two shots with the same geometry (28k -> 1k mach 0.9, 20 miles)

AIM-54C

https://cdn.discordapp.com/attachments/608271675493974026/986371073689911356/unknown.png

 

AIM-120C

https://cdn.discordapp.com/attachments/608271675493974026/986371262131601428/unknown.png

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  • 2 weeks later...

Hello, it's me again with more Missile Guidance Quirky Fun!!!!!!  On today's episode, attempting to get an AIM-54 variant into space!  Also, maybe an exaggerated case study on the lateral guidance issue I brought up earlier.  And finally, we look at the AIM-54C putting on it's best glider impression!  You are probably wondering how I got here, so 

Test Setup:
F-14:  33k feet, Mach 1.8(ish), travelling due north
Su-33: 36k feet, Mach 0.75, travelling HDG 210º - Set to Not React

The first set of shots I performed were using the AIM-54C and AIM-54A Mk60 at ~70nmi.  Lateral guidance is improved compared to the previous tests, but the problem persists in both cases.  I stepped this out to 85nmi to exaggerate the arc, and it got worse.  This got me thinking about the lateral guidance issue some more... a huge chunk of what I'm guessing is missing from the "equation" here is air resistance.  At shorter ranges, it largely doesn't matter, but at the longer ranges, the difference here is quite large.  See the picture below:
woah4.PNG
The above picture is a shot taken at 115nmi in STT against a Mach .65 Tu-95 at 36k feet.  The Missile is an AIM-54C.  It hit a peek altitude of 150,020 feet!!!!  As it was coming down in the loft profile it started pulling massive lead to try and catch up to the Tu-95 it was now trailing behind (showing the incorrect computed impact point).  As it got lower in altitude, it pulled less lead because the air resistance was actually providing the desired corrections as the fins started to work correctly.  

Thing is, this missile MISSES the target, but not because of any lateral issue.  It ran out of battery.  We'll talk about that here in a second though.

Because I was using the AIM-54C, which is slower, I decided to switch to the AIM-54A Mk60.  The results were frightening...  In terms of lateral guidance, the AIM-54A Mk60 has the same issue at these ranges.  The difference is the AIM-54A Mk60 is moving fast enough that the computed lead angle is "more" correct, so while there are still large corrections in the lateral guidance as it comes down from the bozosphere is "more" correct.  Also, speaking of bozosphere trajectories... the AIM-54A Mk60 hit a PEEK ALTITUDE of 171540 feet.  For perspective, I'm at 33k feet, and space starts around 328k feet... so half way to space! 😄  The AIM-54A Mk60's faster speed, and higher peek altitude actually gets it to the target with time to spare on the 240 second battery life.  Impact speed, just over Mach 3.0!!!!!!!!!!!!!!  The impact angle is also B-E-A-UTIFUL!

itallianhands.PNG

🤌Money!!!!

 

Lateral Guidance Lesson Learned?
nullClearly the issue here is a combination of air resistance (actually, lack thereof in the mid course), and the initial launch angle being incorrect.  The two, together, cause for some interesting energy bleed at long ranges and the "arc" in the lateral guidance... Because I'm not 100% familiar with who handles this in DCS, I'm not sure if this is a Heatblur thing or a ED thing?  I'm guessing it's an ED thing after launch, but before and at launch is Heatblur? Maybe @IronMike can share some insight?

 

To SPACE!!!!!
Well we didn't quite get there... in fact subsequent attempts to shoot at things at excessive ranges resulted in some uhhh... interesting behavior.... but not exactly space.  The only thing really interesting to report is the ability to smack Tu-95's and Tu-22's at 160-165nmi ranges with the AIM-54A Mk60.  I was able to hit my Tu-95, from 45k, at Mach ~1.75 at ~161nmi in PDSTT... @777coletrain was able to smack his Tu-22 at 165nmi IN TWS only going Mach 1.2 at 42k.  Yeah, that's pretty epic!

Loft Profiles and AIM-54C Glider Competition
Where things get interesting is the loft... maybe not the actual lofting maneuver, that looks pretty good, but the glide down from max altitude... in shots above about 80nmi, the AIM-54C starts the descent to the target earlier than the AIM-54A and then does a linear (vertically) intercept.  The AIM-54A Mk60 comes down in a nearly perfect ballistic arc like we'd expect.  Not sure what is going on with that vertical guidance, but this is what it looks like:
woah3.PNG

The AIM-54A Mk60 at slightly longer range in comparison:woah2.PNG

I believe this has already been brought up to Heatblur/ED before, so I'm not going to keep posting about those tests.

Conclusion
I believe the lateral missile guidance issue is related to a combination of incorrect original lead angle, and lack of air resistance calculations being factored in or some combo of both.  The vertical guidance issue is at least known, so I'm not going to beat that drum any more than I have.  I'll post track files in a follow on post.

 

F1454AMk60Test1.acmi F-1454CTest1.acmi F-1454CTest2.acmi WhatistheAIM54Adoing.acmi WhatistheAIM54doing.acmi


Edited by Whiskey11
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