AIM-120 Help
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is it possible to count both range values ( radar activation) for both settings ?- typical and small
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is it possible to count both range values ( radar activation) for both settings ?- typical and small
I don’t know.
Could you make a TE and just fly at a ‘drone’ while you have a live AIM-120 and see what the range is when you get ‘pit bull’ cueing? Then change the RCS selection and try it again?
There might be something in the DB values, but I have no idea where to look or what to look for.
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I found that the AIM-120B and C tends to go active at approximately 7 to 16nm when shot at by AI. You can do similar tests as Agave_Blue mentioned. I would roll the plane as a cue for when the seeker went active to check the distance on the ACMI tapes.
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wait, so the pitbull cue means the seeker went active? i always thought that it meant that i missed the intended target.
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wait, so the pitbull cue means the seeker went active? i always thought that it meant that i missed the intended target.
PITBULL : The Active radar Missile is at MPRF active.
In doubt, there is a reference doc in your install folder, “Joint brevity word publication (APP-07E).pdf”
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facepalm
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I like to turn off the pilot voice in setup so that I can determine when I can snip the missile myself. I found myself waiting for the computer to say pitbull as a crutch. The manual explains the letters so that it is hard to know what to look for on the Hud. I simplified it in my head to M=Husky and T=Pitbull to make it easy to know when I can snip the missile and not have to wait for the computer to say pitbull.
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I dunno, the letters make sense. A - time until active, M - time until MPRF switch, T - time until terminal.
I think associating T and pitbull would confuse me, being on a countdown timer I just automatically think “time until”.
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Set the RCS selection on the MFD (?SMS) from UNK (typical) to Small?
As I understand it, Large will turn on sooner (requires less support as the seeker can find the large RCS contact easier), so Small should require longer support until pitbull.
Agave,
negative on this one. With this selection, you can only influence how your FCR calculates the theor. value for H/MPRF. Since there is no backlink from the missile (not in this version) there is no way the F16 can know that the Slammer went active. It does calculate this point based on a formula and its current reads on the radar and the (known) flightpath of the missile.
This mean, with a larger RCS it is INDICATED that the slammer woke up earlier, and vice versa -> you cannot influence that time point same as you cannot influence anything on a slammer once it is off the rail.
stingray
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…. It does calculate this point based on a formula and its current reads on the radar and the (known) flightpath of the missile.
This mean, with a larger RCS it is INDICATED that the slammer woke up earlier, and vice versa -> you cannot influence that time point same as you cannot influence anything on a slammer once it is off the rail.
stingray
I guess my question would be: Is what you can see in the FCR/HUD symbology calculated differently if the radar RCS value is changed on the SMS page? IOW, are the FCR/HUD predicted/indicated values for MPRF/HPRF changed if you change the RCS selection?
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Agave,
negative on this one. With this selection, you can only influence how your FCR calculates the theor. value for H/MPRF. Since there is no backlink from the missile (not in this version) there is no way the F16 can know that the Slammer went active. It does calculate this point based on a formula and its current reads on the radar and the (known) flightpath of the missile.
This mean, with a larger RCS it is INDICATED that the slammer woke up earlier, and vice versa -> you cannot influence that time point same as you cannot influence anything on a slammer once it is off the rail.
stingray
Thanks for comment. This is interresting.
But I thaught Aim-120D does have the datalink.Ok, we have C version in BMS. Does it mean, it is impossible to change seeker activation range in RL? I know, there is no D-link in C version, but I mean preprogramming on the pylon.
If it is not adjustable…it means from F22 fired C Amraam would always warn bandit at 15km distance. -
Agave,
negative on this one. With this selection, you can only influence how your FCR calculates the theor. value for H/MPRF. Since there is no backlink from the missile (not in this version) there is no way the F16 can know that the Slammer went active. It does calculate this point based on a formula and its current reads on the radar and the (known) flightpath of the missile.
This mean, with a larger RCS it is INDICATED that the slammer woke up earlier, and vice versa -> you cannot influence that time point same as you cannot influence anything on a slammer once it is off the rail.
stingray
Without a datalink, your comment doesnt make much sense.
You are saying that a large RCS target will influence when the slammer turns its radar on, and that this is independent of the setting on the FCR, and dependent only on the RCS of the target.
The slammer doesnt know the RCS of the target. It doesnt know until it turns its radar on, at which point its at HPRF range. Therefore, the actual RCS of the target cannot influence the wake time of the missile unless it knows the RCS when it leaves the rail, or unless it is sent to the missile by a datalink after launch - which you reckon doesnt happen, otherwise the FCR would know that the slammer went active.
Agave_Blue’s understanding of the functionality of the target size selection is consistent with what Ive read somewhere. Problem is, I cant recall where… and if he (and by extension myself also) is wrong, Id be rather interested to know that.
1.7.3.6.2.24 Target size for the AIM-120A is controlled via OSB 17 on the AIM-120 weapon page (Figure 1-71). Depressing the OSB will rotary through the four selections (SMALL, MEDIUM, LARGE, and UNKN). Target size is the only geometry parameter an AIM-120A can accept, assuming that target decoupled physical size and radar cross section are always correlated. UNKN is selected if power is cycled on the ground. Physical target size and radar cross section for the AIM-120B/C missile are controlled via OSB 18 and 8 respectively on the AIM-120B/C weapon page. The AIM-120B/C missiles can accept both physical size and radar cross section information. The missile receives fuzing information based on the options selected. These options will remain through power cycles in the air. UNKN is selected if power is cycled on the ground.
EDIT: Well that was amusing, the information I was looking for was in the BMS manual. Kinda funny after the recent complaints about it not being comprehensive enough…!
@BMS:
The radar model for AMRAAMs now includes HPRF (Husky) mode for favorable target geometries. The missile will activate the seeker well before the normal MPRF (Pitbull) range and attempt to track. HPRF is better at tracking high aspect targets with high closing range rate. Datalink guidance will continue up to MPRF unless the pilot commands a snip (drops the radar track) before that time. During HPRF with host DL guidance, the missile will use the best tracking solution available (either seeker or host DL guidance). HPRF and MPRF activation are now entirely based on range to target (used to be time-to-run based). Ranges coded are rough guesses for the AIM-120B. Other (active radar) missiles will need specific dat file edits (the AA-12 has been done already). The variables are:
AspectSelectorSize – HPRF requires target aspect to be within this many degrees of 180.
HuskyMinClosure – HPRF will not activate unless range rate is higher than this threshold
HighAspectBomberHusky – Select LARGE target (AIM120 SMS page) to use this as HPRF range gate
HighAspectFighterHusky – Select MED or UNKN target (AIM120 SMS page) to use this as HPRF range gate
BomberPitbull – Select LARGE target (AIM120 SMS page) to use this as MPRF range gate
FighterPitbull – Select MED or UNKN target (AIM120 SMS page) to use this as MPRF range gateNote: you can select SMALL in the SMS page. Doing so doesn’t make a lot of sense in Falcon4 since this is apparently intended for targeting small RCS targets although it might be useful against helicopters. If you do choose small, MPRF ranges are reduced by around a third compared to MED.
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Without a datalink, your comment doesnt make much sense.
You are saying that a large RCS target will influence when the slammer turns its radar on, and that this is independent of the setting on the FCR, and dependent only on the RCS of the target.
The slammer doesnt know the RCS of the target. It doesnt know until it turns its radar on, at which point its at HPRF range. Therefore, the actual RCS of the target cannot influence the wake time of the missile unless it knows the RCS when it leaves the rail, or unless it is sent to the missile by a datalink after launch - which you reckon doesnt happen, otherwise the FCR would know that the slammer went active.
Agave_Blue’s understanding of the functionality of the target size selection is consistent with what Ive read somewhere. Problem is, I cant recall where… and if he (and by extension myself also) is wrong, Id be rather interested to know that.
EDIT: Well that was amusing, the information I was looking for was in the BMS manual. Kinda funny after the recent complaints about it not being comprehensive enough…!
I looked in the documentation and didn’t see these 4 variables. Do:
- HighAspectBomberHusky
- HighAspectFighterHusky
- BomberPitbull
- FighterPitbull
not exist anymore in the .dat files?
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Well, the documentation has been replaced now that 4.33 is out. I had thought that in 4.32, the variables for the AIM-120 were hardcoded, and that other missiles needed specific lines added to the .dat files.