TWS extra

[colubridae]

I set up a test with four inbound IL-76s.

 

TWS designated them all.

 

fired 4 aim-120 in v rapid succession.

 

about half way through their flight I switched off my radar.

 

v interesting to see where they went.

 

have a try...

 

col

[S77th-GOYA]

At what range did you fire?

[colubridae]

they were inbound and I fired from abiut 14nm.

 

leaving the radar on, all four missiles hit thier intended target.

but switiching the radar off, shows that the modelling is doing what it is supposed to be doing. i.e. some of the missiles continued and hit, some lost lock and re-locked on another target some lost lock and missed

[Pilotasso]

Thats supposed to hapen but IMHO they still reaquire too easely. You can efectively STILL maddog missiles from 20 miles away. I see people who are mostly dependent from that tactic.

[S77th-GOYA]

the modelling is doing what it is supposed to be doing.

 

 

When should AMRAAMs go active and no longer need guidance from the launching aircraft?

[Guard]

When should AMRAAMs go active and no longer need guidance from the launching aircraft?

 

Guidance from the launching aircraft after the launch is not indispensable, since the aircraft passes data to the missile just before launch, giving it information about the location of the target aircraft from the launch point and its direction and speed. The missile uses this information to fly on an interception course to the target using its built in inertial navigation system.

 

So if the target aircraft doesnt change its direction and speed, there will be no difference for the aim-120 whether u keep tracking the target until "pitbull" or just unlocking after the launch.

 

Keep tracking the target and giving the missile periodic updates about target's information is only necessary when the target changes its direction or speed.

[Pilotasso]

well you cant count on the target to always fly straight. 99% of the cases it will fly off the parameters on the AMRAAM if you only give it initial lauch parameters.

[S77th-GOYA]

Guidance from the launching aircraft after the launch is not indispensable...

 

After the Slammer goes active it is autonomous. Meaning it recieves no mid-course updates via datalink. The range at which this happens was the question. I have heard that if fired within WVR, it is truely fire-and-forget. I have also heard BVR described as 20nm or greater. Although one could piece that info together and say that the 120 goes pitbull at 20nm, I prefer to refrain from such leaps in logic.

 

One thing I do feel is certain. 4 AMRAAMS fired at 4 targets in relatively close formation would most likely not end up with 4 splashes. Once they go active, they would likely all lock the same radar return. But then again, they could be "smarter" than I think they are.

[FVMAD]

The range at which this happens was the question.

 

At 10nm from missile to target AIM-120 goes active and autonomous.

[S77th-GOYA]

Real or LOMAC?

[GGTharos]

The real missile's Active range is dependent on fuze setting/target size.

 

I think I'm repeating myself here huh? In any case, on the 'medium' setting typically used for fighters the 'active range' is 13nm/25km. This, IIRC, is HPRF range and is a 'cheapshot' if you break lock there - don't quote me on that though.

 

In LO, the missile will go active if:

While you are guiding it, it comes within 15km of the target.

You lose lock, in which case detectiona nd lock capability for the missile is again 15km. The same applies to R-77.

 

SARH seekers also activate at 15km, at which point they supposedly ignore MCUs.

[Frostie]

Isn't there a countdown on the HUD? IIRC it is featured in LOMAC or am mixing it with F4?

 

GG could you explain MCU's statement regarding SARH pls.

[GGTharos]

Once a SARH missile's seeker activates, it takes over guidance, and overrides Mid-Course Updates completely in most real weapons. This function is present to some degree in LO as well.

 

And yes there is a count down on the F-15.

[S77th-GOYA]

13nm/25km. This, IIRC, is HPRF range and is a 'cheapshot' if you break lock there - don't quote me on that though.

 

Sorry, I quoted you on that. :harhar:

 

You mean, by HPRF range, that that is a blind range? Also, if the 120 is active, why hold the lock? It's autonomous, no?

[GGTharos]

Well, HPRF is good at detecting head-on targets, MPRF is good for just about any aspect, but pulse power is lower, so range is lower.

The AMRAAM will go active at HPRF range, then switch to MPRF as it closes in or when it achieves detection (or whatever parameters it must meet)

 

The reason that HRPF would be a 'cheap shot' is that if the closure is relatively low (ie. aspect problem) then HPRF might not pick up the target and subsequently the 120 might miss.

 

MPRF range would be 'Pitbull'.

 

If the 120 goes active, it is possible that datalink data is still somehow blended with guidance singals (Which is typically not done on older missiles if we assume that the R-27 represents such a typical weapon), permitting better penetration of ECM and whatnot. But I'm just guessing ... the AIM-120D has a 2-way datalink, so the FCS will know what the missile is up to, and as such it can 'help' the missile.

 

In any case, if you have a missile coming your way, you pretty much have no reason to hold the lock once your missile goes active - you have the advantage here against a SARH at the least, and you don't really want to tango with an ARH so breaking away is probably the right thing to do.

[golfsierra2]

When should AMRAAMs go active and no longer need guidance from the launching aircraft?

 

IMHO it depends on the aspect, the target cross section and the missile energy potential ...

 

In FC, I think below 15 km there is no chance to evade it any longer.