The missile hit mach 4.44 at motor burnout.
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So from this test, it went 73.6 Nm and around 100k ft by estimation. This pretty much matches this scenario. With thrust being correct, it looks like we’re back at looking at drag it appears since it’s not reaching its stated speed. Otherwise it’s quite impressive it’s meeting those other parameters. Thanks for your test!
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Yeah it looks to be performing exactly as on the document. There was a patch where they had changed its loft guidance, battery time, and significantly reduced its drag and I suspected it was to fit this scenario.
Allegedly the AIM-54 is supposed to hit a higher top speed at burnout, but all that would lead to is higher thrust amount but also higher drag so that it would still fit these parameters, but thats all too much work for two missile to just get the same end results. Higher acceleration and higher drag would mean that the missile would lose more speed against manuevering targets due to the higher drag.
To devs, as long as the burntime is correct, the loft altitude is correct, and the distance traveled is correct, then the missile is good enough and performing as it should be.
@MythicPi looks like you might have been bothering stepanovich this whole time while he knew in the back of his mind that the missile was performing correctly, hence the ignoring.
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AIM-54A
It is permitted to use custom models for bugreporting purposes, as well as custom radars, so long as you test the correct data points and you tested the correct unedited missile, and that’s pretty much all that matters.
I’ll assume that if the missile had been able to get mid-course guidance updates throughout, the travel path may have been good enough to make a connection instead of exploding at 0.7km away.
So what is left? With all else being correct, the only other items I can remember being discussed is G pull and reduced smoke but that’s about it.
G pull and reduced smoke is reported to my knowledge from statements of Mig23M and DavidBowie.
What’s not reported is the supposed directional warhead for AIM-54C.
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Directional warheads are not implemented for any missile. It is something that needs looked at soon because quite a lot of the new fox-3s use these including AMRAAM.
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But what missiles has been reported so far? I know of only one. The others including AIM-120s have yet to be reported and to my knowledge, I thought only the AIM-120C and not AIM-120A received it according to your sources but I’ll have to double check them.
At any rate, a source was recently passed showing that missiles older than 2012 are able to focus 70% of the explosive mass in the desired direction, newer missiles are able to focus up to 85% so Gaijin should have the information needed to model directional warheads.
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I would like to point out the shape of trajcetory is very important.
In my rough drawing (not for scale), all 5 trajectories reaches roughly the same altitude in the loft, which by your definition, all 5 trajectories are “good enough and performing as it should be” for Phoenix.
Yet, obviously, Blue trajectory is the most efficient trajectory and spend most time in higher altitude, thus enjoying lower drag; while constantly trading gravitational potential energy for kinetic energy.
The red trajectory is the one you mentioned when fired sufficiently far away and doesn’t cause Phoenix nose dive too early.
The green trajectory is close to the one we had in game when firing around 40km, where it almost always starts nose down towards target around 10 seconds after launch, even if target is still 30km away.
Furthermore, there are infinite number of possible trajectories that phoenix “should be”, just draw a random line, as long as it moves from left to right and reaches certain altitude at some point in time and never exceeds it, then it satiesfies your definition.
This is why papers on missile kinematics almost always use the word “trajectory shaping”, because lofting alone doesn’t bring any benefit if the shape of trajectory is wrong: see black trajectory as an example, clearly it performs lofting and can reach correct altitude in certain condition, thus it satisfies your definition of “good enough and performing as it should be”, but it will perform even worse than current implementation since it will fly level even when fired in lower altitude thus experience much greater drag, and players will almost never see it loft in action.
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This is not what is being stated as being, “good enough”. Obviously @legocubed can give you the better details by explaining how it lofted, but the graph you made is inaccurate. In the graph, you say
while showing that it is not reaching the correct altitude compared to other lofting profiles. The test Lego did proved that it reached the altitude from the picture Mythic provided, indicating the lofting profile is most likely correct. If the target is 30km away, the Pheonix should almost certainly burn straight towards it after a slight loft.
If AIM-54 was to be changed to a better or more efficient loft mechanism such as the ones on MRAAMs, then it would be overperforming, and they’d have to nerf the missile by increasing its drag to make sure it doesn’t travel more than 72.5nm in the 110nm shot. So the end result would still end up being the same.
It doesn’t stall at 75nm, it runs out of battery power
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On top of that, improved trajectory shaping improves its performance at lower altitude significantly, and we also know from historical footage that Aim-54 climbs at an angle much greater than 15 degrees. Thus even if the number matches, the shape of trajectory is still incorrect: Aim-54 should start with much more aggressive climb and still reaches same max altitude.
This means Aim-54 should reach the max altitude much sooner than Lego had shown.
If you read my post carefully, the green line is what we have when firing at targets around 30-40km in game.
Of course green line is not reaching desired altitude, that is exactly what green line meant to show: it is depicting 30-40km shots that is most common in game, which the missile doesn’t really loft much and doesn’t try to maintain altitude.
Reasonable question, why should it in this case? In most scenarios that this is done, the motor burns out and then reaches the target in about 10 seconds or less. And most of the time that I observe this, it is still burning as it went active. I would imagine that shots within 40km will not reasonably benefit from any lofting due to the motor still burning.
Edit to add: excessive lofting, in this case. It still lofts slightly.
That’s the problem I’m trying to bring up. Why the slower and higher drag Aim-54 must point its nose at target while being 30km away, it still takes about half minute to reach target, if 30 seconds is not enough time for loft, then why faster and lower drag Aim-120 or other newer ARH that can reach target in much less time gets much more aggressive trajectory shaping than Phoenix? If one wants to cite insufficient avionics, but we have historical footage that shows Aim-54 climbed very aggressively immediately after clearing the launch aircraft. The angle of climb is wrong, thus the shape of trajectory is wrong.
I think you misunderstood me. It doesn’t stall or run out of battery power when you properly test it. It just simply strikes the target at 72.5nm.
If a more optimized loft was to occur, it would strike the AI target at beyond 72.5nm since it would be faster, which is not realistic.
It benefits significantly from drag reduction and storing energy in gravitational potential energy even if motor is still burning.
The drag difference between 5000m (density 0.73) and 10,000m (0.41) is ~44%.
Even if it only spends 10 seconds at around 10,000m, it gets almost twice amount of kinetic energy from rocket motor during that time period, which means ~sqrt(2.0)=41% increase in dV gained over that 10 seconds compared to flying at 5,000m without lofting.
Then during dive, it enjoys the triple benefits of: gravitational potential energy converted to kinetic energy, higher speed to begin the dive with, and rocket motor propeling the missile downards combined with gravity pulling it down.
Thus significantly increasing its impact speed, hence more energy to maneuver with.
Historical footage and illustrations indicates Aim-54 does perform in this way.
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Yes, if it flies faster in that test, then it needs more drag, but the need of doing this that doesn’t change the fact that the loft angle is wrong. The historical footage already shown the climb angle is wrong and it is much more aggresive.
I also need to add, from the past proof of Aim-54 fired against drone at 18km range, the image depicted Aim-54 lofted as well, unless the depiction is incorrectly illustrated, it means Aim-54 is programmed to perform trajectory shaping even if it is launched against an 18km target. (The lock range against small target is 9km, IIRC)
Update: I found this one on the internet, not sure if this is the one posted in the past.
This claim is wrong, I found this footage, the flight time of missile is around 15-20 seconds, it covered around 10km by the time it hit, the missile didn’t loft when too close.
