Too high for missile to intercept?

[RedTiger]

I've never seen this specifically talked about, but has anyone noticed that if you fire a missile -- any missile -- from too high an altitude above the bandit, the missile is totally incapable of intercepting it? I've watched this over and over on Tacview. I fire an R-27ER from 25nm at an AI bandit, I'm at 20k he's at angles 10. I'm traveling at Mach 1. The missile will fly lead pursuit a short while after launch, it but can't quite make that sharp turn down in time to catch the bandit. All the bandit has to do is keep flying straight ahead. Sometimes the missile has enough energy to turn back at him and chase him for a few moments, other times it just keeps going and plows into the ground.

 

My point is not to add more complaining about the missiles. I'd like to know if this is realistic or not. At the "top" when the missile turns down to intercept, it should have gravity on its side and be able to turn tighter, right? In LOMAC this turn seems to spend a ton of energy and causes the missile to miss. Is it possible have such an extreme difference in altitude as to adversely effect the trajectory of a missile?

[GGTharos]

You must be firing HoJ. HoJ in LO is modeled as taking pure pursuit, and in this case if the missile isn't going to hit the bandit right in the face, it won't be able to keep up with a turn needed to hit the bandit period.

 

Insofar as energy is concerned - missiles need to deflect their surfaces a lot when turning, especially at higher altitudes, higher g, or both - and that creates tremendous drag.

 

To answer your question - this isn't quite realistic. A missile tracking in HoJ should be using un-augmented proportional navigation, if it can in fact detect that it is being jammed.

[S77th-GOYA]

Insofar as energy is concerned - missiles need to deflect their surfaces a lot when turning, especially at higher altitudes, higher g, or both - and that creates tremendous drag.

 

This would seem to make sense for a very tight turn but not a more gentle tracking turn. Granted, not all of the drag force is applied to the missile in the direction of the desired turn but it seems that at the speeds that missiles generally travel, a small deflection would create a strong pivot force.

 

To the OP, LO's missiles need a lot of work. Many of us are frustrated by the types of things that you describe. An advantage in altitude of 10k feet should actually be an advantage.

[GGTharos]

At high altitude you get less g for the same amount of deflection. I don't think that's modeled either though, so you get a double-whammie for low-flying missiles in LO.

 

This would seem to make sense for a very tight turn but not a more gentle tracking turn. Granted, not all of the drag force is applied to the missile in the direction of the desired turn but it seems that at the speeds that missiles generally travel, a small deflection would create a strong pivot force.

[104th_Crunch]

I fire an R-27ER from 25nm at an AI bandit, I'm at 20k he's at angles 10. I'm traveling at Mach 1.

 

Isn't that a very far distance to expect a hit in HOJ? 25nm + your altitude seperation (slant range). Don't ask me exactly the distance, I suck at Trig!

[S77th-GOYA]

At high altitude you get less g for the same amount of deflection. I don't think that's modeled either though, so you get a double-whammie for low-flying missiles in LO.

 

And correspondingly, less drag.

[Pilotasso]

I dont think this is what RT is saying. Neither is he. If your above the bandit very high it is very likely that the missile will be looking down at a very steep angle. When that hapens it just looses track of the target. Either a notch like thing or the angle VS the ground, or both things will cause the missile to go ballistic.

[RedTiger]

First off, I'll have to pay more attention to HOJ. I know for a fact some of what I'm seeing is against a jamming target, but I could swear that in other cases it isn't.

 

As for notching or clutter, I don't think this is the case. The missile doesn't always go ballistic. In many cases, especially with REs, they have enough smash to flip around and actually chase the bandit for a while. So they are definately still tracking!

 

I'm thinking it has something to do with altitude because I just don't see this sort of thing when the altitude difference isn't as great, like maybe only 4000 feet. Conversely, with extreme differences, like 30k vs. 2000 feet, the missile doesn't even get a chance to hit. By the time it turns and is pointing down, the bandit is long gone. I've also noticed that missiles don't make any exteme and immediate dive downwards to targets below them, they seem to have a fairly high trajectory for most of their flight and gently make there way downwards.

[GGTharos]

This really sounds like HOJ shots. Try using it against a non-jamming target, you'll see the missile will dive to an intercept point.

[Pilotasso]

If the missile is facing down a target close to 70-90 degrees, specialy one that is chaffing it will go blind, it doesnt matter the G loading. I have noticed this hundreds of times.

[RedTiger]

This really sounds like HOJ shots. Try using it against a non-jamming target, you'll see the missile will dive to an intercept point.

 

Ok, I'll try that and see what happens.

 

If the missile is facing down a target close to 70-90 degrees, specialy one that is chaffing it will go blind, it doesnt matter the G loading. I have noticed this hundreds of times.

 

The missile will go blind, the plane providing the guidance via radar, or all of the above? :) AMRAAMS will often just drop to the ground because they're slow anyway, but the ERs are still tracking. I certainly haven't gone blind because I still have them locked in a look-up; I have flown below them after firing the missile.

[Pilotasso]

Even if you manage to maintain radar lock the missile will view the grownd through a number of different angles during the trajectory and at one point it will go blind.

 

this is specialy tru if the target is going to pass under you and the missile leads the trajectory.

[S77th-GOYA]

The missile will fly lead pursuit a short while after launch, it but can't quite make that sharp turn down in time to catch the bandit. All the bandit has to do is keep flying straight ahead.

 

Something occurred to me. This doesn't sound like HOJ pure pursuit at all. In pure pursuit, there would be no sharp turn at all.

[GGTharos]

It would be going jammer on after being launched on though.

[S77th-GOYA]

That would have a fairly sharp break upward going from lead to pure but if it stayed pure after that, the pivot downward should be gradual.

 

It would make more sense to think of the opposite happening: The bandit turned ECM off and pusuit went from pure to lead. That would create a sharp down turn.

[RedTiger]

Well, take the term "sharp" with a grain of salt. It may not be as sharp as your thinking. The missile is heading downwards towards the bandit. At one point it has to turn and point almost directly down to have any chance of hitting. It is fairly sharp, like going from 120 degrees to 170 on a compass. At this same moment, the bandit flys right past it. The missile either plows into the ground or turns back at it, say to 270 degrees to chase it for a few moments.

[Rhino4]

Okay...erm...

 

Question: You originally wrote "25nm". Since you are shooting from a russian jet, did you mean 25k? Or were you viewing through tacview when you got this distance measurment?

 

Because if 25k is the correct distance then all this speculation about HOJ is moot because of burn-through at that range.

 

Also:

 

Pilotasso says -

"Even if you manage to maintain radar lock the missile will view the grownd through a number of different angles during the trajectory and at one point it will go blind.

this is specialy tru if the target is going to pass under you and the missile leads the trajectory."

 

I might be wrong, but since we're talking about ER's here... I would assume that the missile doesn't "view" anything at all as it has no radar and is only able to guide through data sent to it from the attacking jet... And anyways, he says the missile doesn't lose track as it turns around and chases the bandit for a while. Yes/No?

 

My opinion is that since the altitude difference is so huge, by the time the missile gets there the bandit would have the missile at his high 3/9 (directly above) and the missile would not have enough energy to maintain lead pursuit... Thinking about it, I realize that you must have gotten your distance measurment from tacview instead of ingame and the shot was taken in HOJ from 25nm. However, (and I haven't tested this so who knows) having started out in HOJ at 25nm I doubt it would end in HOJ as the bandit closes. This accounts for redtiger's "sharp turn" (burn through) near the end of the missile's flight. From the HOJ trajectory, constantly readjusting the flight profile, combined with the "sharp" turn down at burn through, the missile just didn't have the energy anymore. I can imagine that it would turn and follow the bandit for a while (depending on how close the missile is during burn through), but if I am right I would guess that the missile does so from below the bandit's own altitude, and that by this time you are within 20km of the bandit?

 

"Warning: Newbie knowledge at work!"

[cool_t]

What you should try is draging your bandit to your "LOFT" missile.

 

When your at high ALT remember how much "Stored" energy you have at your disposal, not to mention the "Stored" energy in your missile.

 

Hight altitude intercepts are very complex but yet the most elementry engagements known.

 

At the onset of your intercept make sure that you have a "Clear" egress flight path with all of the nessesary "escape" elements in your "forsight" or "Plan" to come out alive.

 

There are 2 different types of engagements.

 

1. Ninja attack: your bandit or bandits can not find you.

 

2. Hellow im here: you make sure that your banddit or bandits see your radar emissions or your jet on there radar buy using ECM or just flying in the bandits radar cone.

 

There are many alternatives and or variations which you can apply your "stored" energy in this type of engagement.

 

Points 2 remember.

 

1. Who are you fighting.

 

2. What are you fighting.

 

3. Where are you during the intercept.

 

4. Why are you taking on this bandit.

 

5. How do you kill him with out being killed.

 

Fill in the gaps and ride the edge, see what works and what gets you killed. Then when it counts, pull out the moves that make people surprised or dead.

 

:thumbup:

[RedTiger]

@Rhino4

 

Yes, the 25nm range is accurate, and its a combo of Tacview and estimation by knowing what the bandit is vs. the strength is on the SPO. I haven't had a chance to re-evaluate any of this, so AFAIK, some of these shots are against jamming bandits. Many times, however, "burn through" occurs during the missile's flight. Does this burn through cancel HOJ for a SARH missiles when they are in-flight??

 

Even though I haven't evaluated it further, GG's responses really make me think this is due to HOJ. The problem is that the missile isn't intercepting the target. It keeps going straight out and only dives at the bandit at the end, rather than diving immediately and going for the intercept. If I get a chance, I'm going to experiment some more tomorrow.

 

@cool_t

 

I didn't really mean this to be a request for assistance on tactics. All I'm interested in is the missile behavior. These scenarios I'm describing are not missions and they are not realistic, its a 1v1 Su-27 vs. excellent AI F-15. I need to try a MiG-29, F-16 or some other plane that I can deny jamming capability in the mission editor.

[GGTharos]

Yes, the HOJ is cancelled for the missiles in-flight when you buirn through. It's interesting when the badit gets the launch warning and you timed it sweetly so the missile's maybe 3-4km away from him by now...

[Rhino4]

What you should try is draging your bandit to your "LOFT" missile.....

Someone didn't read...:music_whistling:

[Dunkan Aidaho]

Yes, the HOJ is cancelled for the missiles in-flight when you buirn through. It's interesting when the badit gets the launch warning and you timed it sweetly so the missile's maybe 3-4km away from him by now...

It's not interesting, it is undermodelling. There is no difference for bandit RWR between HOJ and STT radar modes when the SARH missile is launched, so he should get missile warning right after launch.

[GGTharos]

Actually, he shouldn't get a launch warning in either case.

[Dunkan Aidaho]

Actually, he shouldn't get a launch warning in either case.

Actually he should:) The only difference between launch from STT and HOJ is that in second case carrier don't know distance to the target, but anyway radar is tracking target like in other cases. Missile would not hit without radar track. If radar will be turned off - you will loose your missile.

 

Do not make mistake - SARH missile can not lock jammer source by itself, carrier only guide it towards the jammer source in hope that seeker will lock spotlighted target from distance where datalink is no longer available or sooner. If this does not happened, missile has no chances to hit.

 

Sorry for such explanation - I don't know english equivalents of some specific terms.

[GGTharos]

Yes, he should get a lock tone. He shouldn't get a *launch* tone, unless lock=launch. ;)

 

There's not change in radar waveform for most modern radars to differenciate lock/track from launch. This is the only part of your explanation that I view differently from you.