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.
This is leaving out the time that it takes for the missile to climb to these altitudes, if we consider its acceleration, which means the missile will have to take more time, climb more aggressively, and use more propellant just to reach that, then have to aggressively pitch down again to reach that target. I see that as a significant waste of energy considering the metrics of this missile.
The missile lofts at closer ranges as well, as I had witnessed this doing so during the missile test flight (climbs above before burning straight towards the target). I do not think lofting is the issue the Pheonix has, and comparing it to lighter missiles with less propellant isn’t a good way to judge if it’s lofting correctly or not. Which from what I could see, the lofting of the ARH in testing was WIP, not entirely representative of what they do.
I will take time to look at what my missiles do and fire them further, but unless a higher g load is given to the Pheonix, more aggressive lofting would almost certainly be useless in the scenarios we use them in.
The cause of “waste of energy” is due to drag, slower speed = less drag. Higher altitude = more potential energy, thus less energy to lose to drag when pitch down aggressively.
When pitching down aggressively, the shape of missile becomes more of a cyclinder flying sideway into airstream: drag coefficient increases. Surface area increases as well.
However, the drag it losses is not ecessive due to reduced air density.
If missile’s speed is 30% higher compared to not lofting, since drag has squared relationship to speed, so drag should increase by around 1.3x1.3=1.69=69%, then it is multiplied by ~0.6 (due to 40% reduction in air density), which gets you 1.69*0.6 = 1.01
The number says the reduction in air density cancels out the energy loss due to aggressive pitch down. It loses roughly the same amount of energy as if the missile performs the same maneuver at base speed (that was used to multiply 1.3 with) when flying at 5,000m.
Sorry I can’t perform this since myself since I haven’t figured out how to use CDK.
If possible, please perform this test with Aim-120’s loft code on Aim-54 against a target 30km away.
My hypothesis is, based on my previous calculations, the Aim-54 should have significantly increased impact velocity when Aim-120’s loft code is applied. Or 35 degrees aggressive lofting is applied (with loftTargetElevation adjusted properly to avoid it enters the dive too soon due to reachi, say -12.5).
Lego can test that, I do not have it downloaded. I was going to use it in the live server as I can find varied targets to test.
Something I can absolutely say is that video shows the missiles turning extremely aggressively especially the split second before impact. Certainly supports having the G load reevaluated.
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The tests I posted screenshots of was done with the modified radar to provide mid-course guidance. Without mid-course guidance the missile drifted too far to lock the target on its own.
I have tried this before (albeit at 80km distance with a large altitude advantage), and the AIM-120 loft code resulted in significantly more speed on impact as well as a noticeably shorter time to impact.
Tomorrow I can re-test with a co-altitude launch at closer range though, and record the exact results.
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Please and thank you very much.