The AIM-54 Phoenix missile - Technology, History and Performance

[MythicPi]

I think i may have explained myself poorly.

The loft code has not changed in form or function with the new fox 3’s, the values just make more sense, so the missiles actually loft. As can be seen above, all that was changed to gain that performance improvement was 3 values out of 4 that define the loft profile of a missile in WT. The exact code used for the modified loft profile was literally provided. This isnt groundbreaking stuff…

AIM-120A vs AIM-54C guidanceAutopilot code:

There is no difference in the loft code besides the values used, and the timetogain code is already on MANY missiles in-game, its just oddly not on any of the AIM-54’s, and I’m trying to figure out what the justification for that is.

As I’ve explained previously, the loft code in WT is OLD, and many ground attack weapons also have loft code, the timetogain code is also old, with it being implemented with the AIM-7F, which pre-dates the AIM-54A/C in-game. The AIM-54’s just “happen” to have some of the worst values set for its loft profile, which makes it barely loft, and the energy management code is entirely missing…

Not exactly “new and in testing” when all the code im asking about is almost 3 years old and seen on dozens of weapons already in-game…

It seems questionable at best that the missile which would be able to best take advantage of lofting, and whose primary role is long range interception has the worst loft code and literally no energy management code.

[MiG_23M]

Testing by others doesn’t show such a large improvement in performance with slightly higher loft angles.

Peak velocity went up by 0.1 mach, impact speed went up by 0.05 mach… The conditions are given and that is comparing the current loft angle to 35°…

@Gunjob I think Mythic is exaggerating or overstating issues again. If he wanted to make a report I’m sure he could, but idk if it is worth the effort to keep pinging Stepanovich and tech mods all the time for these same non-issues.

Oh, and it doesn’t matter at all if target is a much lower alt.
https://media.discordapp.net/attachments/955829235493273680/1222206986343415818/image-73.png?ex=66155ff5&is=6602eaf5&hm=5629699e3e81a3d971458e01c58efcc6136a1ae3e575da8643b5fcb704e01de0&

[MrKrabsPattys]

F16AJ never existed

[MythicPi]

And shouldnt have been added, whats your point? Also, the AJ is more of a real plane than the F-15N

[tripod2008]

@MiG_23M

Peak velocity went up by 0.1 mach, impact speed went up by 0.05 mach… The conditions are given and that is comparing the current loft angle to 35°…

There are differences with the data that Mythic was basing things off and either of the table(s) you have supplied, so is it at all surprising that they have somewhat different results?

They have different ranges(75 vs 80km), launch speeds(Vc of 2.4M vs 2.1) and Altitudes between ((9km vs 6km Co-altitude, & LD) every set.

And as such they will be impacted by their Autopilot coefficients and drag constants differently , let alone if they were adjusted or not.

@MiG_23M

Oh, and it doesn’t matter at all if target is a much lower alt.

I don’t know, does a TTK delta of; 0.3 vs 2 seconds not make a massive difference? Let alone the TTK being reduced by more than 10 seconds? as per your table(s)?

[MrKrabsPattys]

Do you want another strike aircraft as an event reward?

[MythicPi]

Not like strike aircrafts are the only thing there are prototypes of, its just because gaijins lazy and likes reusing models for “event rewards”. They could add the F-111B and it would be a cool event vehicle if they fixed the AIM-54’s a bit more.

Also, the F-15N and strike aircraft rewards are pretty off topic for an AIM-54 thread

[MiG_23M]

@tripod2008

I don’t know, does a TTK delta of; 0.3 vs 2 seconds not make a massive difference? Let alone the TTK being reduced by more than 10 seconds? as per your table(s)?

The time to kill difference was only so large when comparing to the 0° loft edit, the normal ~17° loft exhibits very similar performance to the 35° loft.

Please read the charts properly and don’t reply for Mythic. He can just stop pretending he’s blocked me and participate directly.

Of course the testing done has different results - it isn’t aimed towards making the AIM-54 look as though it is underperforming. He’s clawing for things that he thinks will make a difference and they won’t. It’s actively stirring up drama without good reason.

I don’t think 2s and 0.05 mach higher speed at the end of the engagement is going to be noticeable, since 80km is already a stretch for the use-case of the missile. You’d want it much closer to peak speed to maintain maneuverability… Which is at 30s or so (right at end of burn).

[tripod2008]

@MiG_23M

The time to kill difference was only so large when comparing to the 0° loft edit, the normal ~17° loft exhibits very similar performance to the 35° loft.

It was the 9km table vs results from;

The AIM-54 Phoenix missile - Technology, History and Performance

some aim54c loft test all M1.2 9000m 75km launch vs M1.2 9000m 1.in game, 17.5° loft [54 17.5] [image] 2.old game (from 2.17) , 7.5° loft [54 7.5] [image] 3.tested 35° loft [image] 4.derby loft the missile dive too late, and miss target due to strange LOFT code [image] [54derby1] [54derby2]

The AIM-54 Phoenix missile - Technology, History and Performance

Realistically speaking, for WT, I dont think testing above 10km alt or above M1.5 is particularly useful unless there’s a known test to try to compare it to, or if you’re trying to find the in-game limits of a missile. Maps are simply too small and the F-14 simply doesn’t have the grunt in the engines to get above M1.5 in a reasonable amount of time. I know I personally tested and mentioned in an earlier comment ( https://forum.warthunder.com/t/the-aim-54-phoenix-missile-technology-history-and…

which Mythic had requested that they be expanded on, and so likely what the subsequent position(s) were based off.

@MiG_23M

Please read the charts properly

I have? The fact that various properties are not similar limit the potential to draw conclusions based on both of the charts that were presented.

@MiG_23M

it isn’t aimed towards making the AIM-54 look as though it is underperforming.

It’s not that it’s underperforming, but non-optimal and thus SSPk / terminal performance could be potentially improved by adjusting the numbers especially considering we lack detail for the actual lofting schedule / shaped trajectory methods that the AIM-54 specifically employs.

Though if it was anything like the Maverick, pulling 3~4G vertically until 20 / 16 degrees of vertical seeker angle was achieved and held until impact would be interesting to see if it could be made work.

@MiG_23M

already a stretch for the use-case of the missile.

Considering that maximum ranges for the AIM-54 are listed as 52 / 63 nmi [96, 115km], 80 km is somewhat close to the listed maximum range or a multiple release, its not completely without merit.

As any missile with a complex autopilot implementation nailing down the root cause of issues is difficult at best, as the potential to isolate issues and work backwards to suggest improvements can have knock-on impacts elsewhere, which would need to be considered.

@MiG_23M

Which is at 30s or so (right at end of burn).

Depends how aggressive the loft angle and the details of any potential trajectory shaping constraints are, since with any induced super-elevation effective Net thrust is reduced, due to gravity, and assuming a TWR <1 there will be some profiles where the peak speed is not at end of burn, let alone the impact of non-constant propellant burn.

I’m sure that the details of said impact on optimal terminal performance (range) vs loft angle could be compiled for various launch conditions, but it would be significant work to map all conditions even if interpolation was used to find the relevant points of inflection.

The place to start would be to figure out under what conditions the missile’s G-limit is reached.

[MiG_23M]

@tripod2008

Depends how aggressive the loft angle and the details of any potential trajectory shaping constraints are, since with any induced super-elevation effective Net thrust is reduced, due to gravity, and assuming a TWR <1 there will be some profiles where the peak speed is not at end of burn, let alone the impact of non-constant propellant burn

This wouldn’t be a useful situation for comparison to the game. They want enhanced loft, increasing loft angle won’t do that as shown.

[MythicPi]

I take it from the fact you’re arguing with someone I have blocked that MiG_23M is disagreeing with the tests done by @dark_claw and hasnt even bothered to properly replicate the test, and possibly not even the changes to the loft profiles code provided by Dark_Claw?

Pretty typical of him to perform improper tests then draw conclusions to match his beliefs. Its because of that type of intellectual dishonesty and general attitude I dont interact with the guy anymore.

[MiG_23M]

You can just reply, they can see that you’ve read my posts.

9km co-alt with high launch speeds yielded a 2s sooner time to target and 0.5 mach higher end-game velocity.

In the much more realistic scenarios I provided, there was no significant improvement… 0.05 higher mach when hitting target…And it gets worse as you make the scenario more realistic for an air RB match. If you launch at a low alt target from high alt and reasonable speed line 1-1.2 mach, missile doesn’t gain any advantage with the higher loft angle.

You’re still exaggerating issues but you’re unwilling to run your own tests or make a report… I think we are all tired of it.

[_ShadowFang]

Frankly, I find myself agreeing to MiG_23M’s observations based on bug reports he does. I disagree with his opinion somewhat when it comes to lofting and higher alt TTK, but the referenced test was also done at impractical ranges (80km) so I can see why he says that’s ultimately pointless. He has also constantly advocated for fixes that improve the missile such as reducing the drag where practical, so from my point of view I find the lack of your interaction of him quite odd.

[Macron-Spokesman]

@_ShadowFang

but the referenced test was also done at impractical ranges (80km) so I can see why he says that’s ultimately pointless.

80km range and 9,000 meters in altitude which is unrealistic in-game yeah. Any changes to loft in the Phoenix won’t yield game impact differences unless much bigger maps is advocated for that would allow the F-14 to stretch its legs which I maintain is the biggest hindrance to the Phoenix outside of its drag.

[_ShadowFang]

The lack of big enough maps is an issue, yeah. As of current the practical range is 30-35km for a target at low alt, which is already quite close when you have to support them. I still don’t like shooting at higher alt opponents since it loses lock quite easily, otherwise I would use it more against high fliers.

[Macron-Spokesman]

@tripod2008

Considering that maximum ranges for the AIM-54 are listed as 52 / 63 nmi [96, 115km]

Maybe I’m missing the context since I don’t read this thread often, I thought the actual maximum ranges are 200km irl?

[MythicPi]

75km range for a 9km alt launch at Mach 1.2 isnt exactly unrealistic. Those are launch conditions that could easily be acheived in-game, particularly on the EC sized maps, though you would likely launch from closer in to maximize pK.

The fact the impact point chosen by the tester was 75km doesnt change the fact that modifying 3 values in the loft code (loftElevation 17.5 → 35, loftTargetElevation -7.75 → -15, loftTargetOmegaMax 0.25 → 1.0) increased impact velocity by 36.1% out at 75km.

Its entirely possible that similar gains in impact velocity can be gained at “more realistic” ranges typically seen in WT as well. As I’ve previously pointed out, the modified loft code used in Dark_Claws test had a higher impact velocity from a 75km shot than a test I’d done previously with almost the exact same launch conditions, but against a 46km target: The AIM-54 Phoenix missile - Technology, History and Performance - #1279 by MythicPi

This would indicate that by simply modifying 3 values in the loft code, the AIM-54 can gain something in the ballpark of ~63% effective range when compared to a “typical” WT AIM-54 shot, which is a MASSIVE increase. Obviously theres variance in how much the loft will help depending on target range and the likes, but we’ve already got a few datapoints compairing current loft code AIM-54C’s to improved loft code AIM-54C’s and the performance differences are pretty obvious.

I’d personally test it at varied ranges and with more varied changes to the loft code, particularly since Dark_Claw had the decency to actually explain what all of the 4 loft variable actually do (functionally atleast), but I dont actually know how to make custom missiles, so I have to depend on the occaisional forum-goer that does know how and ia generous enough to test.

[Macron-Spokesman]

@MythicPi

This would indicate that by simply modifying 3 values in the loft code, the AIM-54 can gain something in the ballpark of ~63% effective range when compared to a “typical” WT AIM-54 shot, which is a MASSIVE increase. Obviously theres variance in how much the loft will help depending on target range and the likes, but we’ve already got a few datapoints compairing current loft code AIM-54C’s to improved loft code AIM-54C’s and the performance differences are pretty obvious.

My problem with this theory is that it’s based upon the assumption that the AIM-54 should obtain the best lofting profile possible with no possibility that the IRL counterpart may have had inefficient lofting profiles.

Some of the documents for later AIM-120s such as AIM-120C and AIM-120Ds indicate that some range increase is attributed to better guidance. This would lead me to believe that earlier missiles including the AIM-54 had some inefficiencies in its guidance mechanisms.

Otherwise optimum lofting codes + energy management applied to all ARHs would leave Gaijin little to no space for improvement in guidance for later missiles.

You would essentially see the best optimum guidance mechanisms that should be reserved for AIM-120D and R-77-1 placed on the R-77, AIM-120A, MICA, AIM-54

[tripod2008]

@DirectSupport

Maybe I’m missing the context since I don’t read this thread often, I thought the actual maximum ranges are 200km irl?

The AWG-9 is not the AIM-54.

The AWG-9 was rated at 115 Nmi(~212km) for nominal detection (not tracking) of a 5m^2 target, thus likely where the 200km stat comes from, though the actual useful Tracking range is far lower at 90 Nmi (~166km) for PD track(s) & RWS / TWS, and ~50 Nmi (92km) for Pulse mode(s) or worse but does not reflect the missile’s capability only that of the radar.

The ALR-23 IRSTS was rated for a 102 to 179 Nmi (188 to 331km) detection range against a Supersonic aircraft at high altitude depending on Aspect angle, though the Antenna Slaved (to the Auxiliary sensor) modes only list a range of 90 Nmi.

@DirectSupport

Otherwise optimum lofting codes + energy management applied to all ARHs would leave Gaijin little to no space for improvement in guidance for later missiles.

They already optimize, simplify and abstract a lot of things about missiles, and I doubt that Gaijin are going to move away from their current use of a Universal PID schema for more advanced missiles, even though they likely use more complete Guidance laws IRL; which is where the improvements come from is that that they can adjust dynamically to target maneuvers post launch to optimize terminal energy and maneuvers

[MiG_23M]

@tripod2008

they can adjust dynamically to target maneuvers post launch to optimize terminal energy and maneuvers

No, the enhanced lofting extended maximum launch range … Not maximum effective. AIM-120C-7+ enhance maximum launch range by reducing weight slightly and using improved trajectory shaping.