Aim120 hud circle question

[Viciam1]

Hi guys,

If there is a bandit in front of me and I just put him in the big aim120 circle thats on my hud and fire...will my missile go get him? 

Thank you

[razo+r]

Not necessarily. It depends on many factors and some settings.

[Viciam1]

Well such as what

[razo+r]

Range, G load, aspect angle, missile "mode" (Maddog, whatever you call that or setting that is) to name a few

[skywalker22]

Aim-120C is a Fox3 type of missile (fire & forget), which means it's has it own built-in radar, which is only activating at cca 5-8nm away from the target, depends of the RCS, speed and altitude; we say it goes Pitbull (MPRF or Medium Pulse Repetition Frequency Active). Aim-120 in real life has some other stage called HPRP (High Pulse Repetition Frequency), which is as I believe, still not modeled in DCS. It helps guiding missile on its own even sooner then with MPRF.

Before those 2 stages, it works similar to Fox1, which means it is guided by the radar from the aircraft is has been shot. But it can also fly on its own, in case if you turn cold (away from the target). When MPFR goes active, and if the radar on missile at that moment can find the target, it will try to follow it to the point of impact.

But there are some things that can disturb the missile`s guidance to the point of impact, and so it can miss it. These are the countermeasures (mechanical: chaffs, electrical: ecm jammer). Missile can also be notched, this means the target aircraft flies at constant 90 degree angle compared to the currently active radar. In the so called notch, the active radar "cannot" see the target (or hardly, which can cause some issues to it to recognize it as a valid target). But remember: it it very hard to notch Aim-120C5 (for example, which is not true for AIM-54 missile). So best no try to notch it, but do other precautious to evade it, like holding the MAR (minimum abort range at all times if possible). 

This is a short and rough explanation, surely there are some other factors when and if hprf/mprf will ever go active, but ok, no need to go into details here.

And to answer on your question, the answer is maybe. As you can see from my post there are many factors which influence if missile will hit the target or not. Also depends from which altitude and speed the missile was fired at, angle, aspect - for you and the target aircraft.

About that circle on HUD (ASEC - Allowable Steering Error Circle), the bigger the circle, the better chances you have to hit the target aircraft. And also closely look at DLZ (Dynamic Launch Zone scale) on HUD, which tells you many important things, like no-escape zone (RTR), which means target can only prevent to be hit by your AMRAAM with evasive maneuvers or countermeasures (or hiding behind some hills or something).

Edited August 2, 2022 by skywalker22

[Laurreth]

The ASE circle before you have a lock is a visual indication that you have an AIM-120 selected and does not indicate anything about a fired missile hitting anything useful (it will not). Once you have a lock, it's getting smaller and you need to put the little steering dot within it.

The symbology with the big circle on the HUD may be a holdover from the AIM-7 that had a "FLOOD" mode where the plane's radar would continuously radiate out in a small cone straight ahead and you'd fire the missile in the hope of it tracking anything useful that might reflect the emitted energy.

Edited August 2, 2022 by Laurreth

[Sacarino111]

HI.

My answer is yes, but the hit depends on many factors. If the bandit is in visual range, the missil will most probably guide into it, if you keep it in the circle and it doesn't not do hard and effective evasive manouvers. Don't know if it is ralistic or not but the easiest thing is to make a simple mission with an F16 (player guided) and some bandits in front, select the AIM120, wait for a visual distance and fire. Keep it in the circle and you will get an impact most of the times.

Again, if there is another plane in the circle you my find it guides to the non desired one, of course.

Saludos.

Saca111

[Frederf]

ASC inside ASEC with ASC not X'd shows valid launch but target may maneuver to defeat the shot pretty much at any time. Even at maximum ASEC size it's still assuming no target maneuver before end game (but good end game criteria). Only with flashing ASEC will have good probability against an immediate post-launch maneuvering target. Of course the maneuver is assumed. If the target jumps to light speed then the assumption is wrong and missile may miss.

[Aquorys]

19 hours ago, Viciam1 said:

If there is a bandit in front of me and I just put him in the big aim120 circle thats on my hud and fire...will my missile go get him? 

If the bandit is bugged on your fire control radar, the missile should "go get him", and the bandit does not need to be within the circle (the ASE circle) for that.

If nothing is bugged on your fire control radar (the radar could even be turned off), you can still fire, and the missile should still "go get him", as long as that bandit is inside the missile's radar cone when the missile gets close enough for the bandit to be within the range of the missile's onboard radar. The bandit still does not need to be within the ASE circle for that, but it is sort of obvious that the bandit would have to be roughly in front of you for the missile to find him. If you'd do that, you'd call out "maddog" on the radio to let your allies know that you have an AT/LOAL mode missile in the air and they had better get out of the way.

[Viciam1]

13 hours ago, Aquorys said:

If the bandit is bugged on your fire control radar, the missile should "go get him", and the bandit does not need to be within the circle (the ASE circle) for that.

If nothing is bugged on your fire control radar (the radar could even be turned off), you can still fire, and the missile should still "go get him", as long as that bandit is inside the missile's radar cone when the missile gets close enough for the bandit to be within the range of the missile's onboard radar. The bandit still does not need to be within the ASE circle for that, but it is sort of obvious that the bandit would have to be roughly in front of you for the missile to find him. If you'd do that, you'd call out "maddog" on the radio to let your allies know that you have an AT/LOAL mode missile in the air and they had better get out of the way.

Cheers 

[skywalker22]

Anyone knows, what's the 1amraam's onboard radar azimuth angle? And if the angle the same all around (in azimuth and "atlitide")?Anyone knows, what's the 1amraam's onboard radar azimuth angle? And if the angle the same all around (in azimuth and "atlitide")?