Does POS-RUK mode for HARMs work well on BMS?
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@Akbar:
Also spotted in that website that the seeker can work C to J bands. That being true, it would confirm that it cannot track VHF search radars, as people (especially monly ;)) have discussed discussed in other topics
Correct. And will be taken in acount in furute version.
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I can track VHF.
Don’t they make mach+2 rabbit ears?
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just finnished reading “Viper Pilot” by Dan Hampton. i found this thread by trying to verify things i read in the book. there is most definitely a “self-defense” mode for HARM employment in the F-16. however, after reading this thread, i am left with more questions.
i am led to believe RUK submode is what is being used in the book. the pilots would launch a quick -88 in a general direction independent of the current steerpoint. the brevity code is a “SLAPSHOT”. the pilots in the book used this on unknown threats that would randomly pop up throughout the mission. based on what i am reading here, it sounds like the HARM wants to follow the current steerpoint in RUK. that seems counterproductive to the intent of the mode.
am i missing something? is RUK not used for slapshots? is this mode not working in BMS like the r/l jet? whats the story?
its a good book. i think many of you would enjoy it.
excerpt from book:
January 19, 1991. Gulf War (first combat mission of author)Looking south, I could only see one contrail left. My RWR was still cluttered with “3” symbols, and the audio warning was screeching in my helmet. But Orca [F-4G flight lead callsign] pulled straight up in a classic last-ditch maneuver. White vapor trails streamed off his wingtips as we came up through the horizon and pointed at the sun. Almost simultaneously, we both rolled in the direction the missiles had to be coming from. More chaff spit out behind him as we zoomed up and continued to roll until we were upside-down again.
He came through the horizon inverted, then sluggishly leveled off. I found myself between the Phantom and the SAMs, so I instantly barrel-rolled over his tail to about a mile behind him. My face was sweaty and I was breathing hard, but it occurred to me that the maneuvers and chaff had worked. At least three SAMs had been shot at us, and we’d survived. And those were three SAMs that hadn’t been shot at the strikers.
“Two Dogs… Slapshot SA-2 bearing two-zero-five…”
My personal call sign penetrated the noise, confusion, and fog of combat, and that was precisely why we used them. A “Slapshot” was a quick-reaction HARM fired along the given bearing. It was supposed to force the SAM radar off the air or, if he stayed up, it would theoretically go right down its throat.
Almost of their own accord, my hands moved, and I pulled the F-16 to a heading of 205 degrees and stared at the HUD. The big pointing cross symbolizing the HARM’s nose hovered over my heading display. My eyes flickered to the bottom of the HUD and I confirmed, again, that my weapons were armed. Swallowing once, hard, I mashed down on the red pickle button and held it. For a long half-second, nothing happened. But as I looked out at my left wing, the jet shook violently and the HARM snaked off the rail.
“Sonofabitch…” It actually worked.
“TORCH Two, Magnum SA-2!”
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There may be RUK modes other than POS-RUK. Depending on the F-16 model and it’s equipment the options available vary. POS-EOM, POS-PB, and POS-RUK are steerpoint-seekers in BMS and there is documentation to confirm this. I could see the value of a “straight shooter” but I have no documentation that is actionable.
It’s possible that in the above passage the missile was fired in POS-RUK seeking current steerpoint but it was deemed irrelevant since the emitter was active and would abandon any steerpoint-seeking behavior so early in it’s flight. Or it was a different “straight shooter” mode. It’s hard to say. Does the book detail the year, country, model, and equipment for that flight?
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Does the book detail the year, country, model, and equipment for that flight?
i don’t think he mentioned what it was for that particular engagement. however, a great deal of that story is in the 2003 iraq war. he mentioned he flew the F-16CJ block 50 with the 77th FS during that time.
switching gears: can HAS mode be used for slapshots? i must admit i am not that familiar with this mode, i don’t use it that often. i’ve been reading elsewhere that the the HAS mode is similar to the F-18s TOO mode. (which would be what i am looking for) i am very interested in “self-defense” style HARM employment. if i can fire quickly after a missile is in the air my Pk should be relatively high. the problem is i should be yanking and banking, not playing around with menus. any help would be greatly appreciated.
source:
http://www.vectorsite.net/twbomb_09.html“The F-16CJ with HTS has three HARM attack modes. The “Position Known (POS)” mode is similar to the Navy PB mode but allows midcourse missile targeting updates. The “HARM As Sensor (HAS)” mode is similar to the Navy TOO mode, and the “Launch Off RWR (LOR)” mode is similar to the Navy SP mode.”
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source:
http://www.vectorsite.net/twbomb_09.html“The F-16CJ with HTS has three HARM attack modes. The “Position Known (POS)” mode is similar to the Navy PB mode but allows midcourse missile targeting updates. The “HARM As Sensor (HAS)” mode is similar to the Navy TOO mode, and the “Launch Off RWR (LOR)” mode is similar to the Navy SP mode.”
POS-RUK can be use for a LOR shot. Your a/c, not the target, has to be close to the current STPT. (iirc I tested up to 20nm from current STPT) The STPT can be behind you with the target in front of you as long as it is less than 20nm. The >20nm could be greater. I quit test after the devs said atm, they were satisfy with the current model.
So in BMS, if you are heading north and a SA-6 pops up to the east on the RWR and you less than 20nm from current STPT you can fire the HARM and it will make wide radius turn toward the emitter. Or, on a clear day you can turn into the RWR bearing, maybe a little off-bore and wait for a visual launch to fire. I tested with the target in front of the a/c’s 3/9 line.
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can HAS mode be used for slapshots?
In the AIM-120 “maddog” sense? No. HAS is like shooting a Maverick. You see synthetic video of a fixed FOV ahead, you select a target, missile acquires, and only then launch.
As for TOO it seems to be a simple case of calling the same function by a different name.
The Target Of Opportunity (TOO) mode, also termed the HARM as Sensor (HAS) or Direct Attack (DA) mode is a lock-on-before-launch (LOBL) mode in which the missile receiver is used before launch to acquire the target. This mode allows off axis attacks on emitters within the field of view of the seeker. It is typically used as an offensive mode by non-dedicated strike aircraft to suppress emitters.
I would be hesitant to use HAS in self-defense simply because any emitter close enough there wouldn’t be enough time to acquire, lock, and fire and any emitter far enough would represent a very skinny terrain grazing angle for a direct HARM shot. It would be likely to hit trees or a hillside coming in so parallel to the ground.
“Launch Off RWR (LOR)” mode is similar to the Navy SP mode."
This is the self-defense mode you want. I’m not sure but it’s possible this was only available in model C and newer. It has a set emitter priority list and will automatically handoff and prepare to fire when left on. It only requires a launch command from the pilot.
POS-RUK can be use for a LOR shot. Your a/c, not the target, has to be close to the current STPT. (iirc I tested up to 20nm from current STPT) The STPT can be behind you with the target in front of you as long as it is less than 20nm. The >20nm could be greater. I quit test after the devs said atm, they were satisfy with the current model.
So in BMS, if you are heading north and a SA-6 pops up to the east on the RWR and you less than 20nm from current STPT you can fire the HARM and it will make wide radius turn toward the emitter. Or, on a clear day you can turn into the RWR bearing, maybe a little off-bore and wait for a visual launch to fire. I tested with the target in front of the a/c’s 3/9 line.
I believe this is because the HARM loft profile is dependent on range to steerpoint and so close to steer = little loft. Little loft = threat in seeker FOV and acquisition. I was successful in having an acquisition of a treat emitter in RUK with a steerpoint well beyond the target but only because I was at a low altitude and it didn’t loft too far above the close threat. I estimate that because the HARM turns like a pig that you could shoot a RUK with a steerpoint 90deg left/right and it would find an emitter dead ahead before it was able to change azimuth significantly. If the loft could be disabled or countered I bet RUK could be a very workable “HARM maddog” no matter where the steerpoint is located.
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thanks for the info. is it safe to assume there is no self-defense type of mode implemented in BMS?
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I definitely see a point in employing HARMs as self defense weapons, though I have yet to encounter a scenario in which this would be required as I always keep an eye on my HAD screen and don’t provoke SAM sites by flying close unless I’m committed to an attack.
If you want to set up your plane for a really quick response time, I’d say go into A-G mode, use the override function on the FCR to bring it from ground mapping to A-A mode, and bring up your HAD instead of your HSD with HARMs selected. If you see something popping up on your HAD screen that engages you, simply slew the cursor to it, fire and take evasive actions. Shouldn’t take more than a second or two, and I can see how it’d pay off against modern SAM systems, as they’ll either have to refrain from lobbing another SAM at you, or even have their targeting radar turned on or take a HARM down the chimney like it’s Santa Claus.
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I believe this is because the HARM loft profile is dependent on range to steerpoint and so close to steer = little loft. Little loft = threat in seeker FOV and acquisition. I was successful in having an acquisition of a treat emitter in RUK with a steerpoint well beyond the target but only because I was at a low altitude and it didn’t loft too far above the close threat. I estimate that because the HARM turns like a pig that you could shoot a RUK with a steerpoint 90deg left/right and it would find an emitter dead ahead before it was able to change azimuth significantly. If the loft could be disabled or countered I bet RUK could be a very workable “HARM maddog” no matter where the steerpoint is located.
I think it’s only based on STPT range. It’s some where between 30nm and 60nm that decides that the HARM loft to the STPT or goes active.
In r/l LOR I think the RWR hands off a vector (and maybe a target type) to the HARM and set the seeker in RUK mode. Then makes hard turn into the vector. <shrug>We only have bits of info on the subject.
I kind of think that PB, RUK, EOM are missile seeker modes.
POS uses PB, EOM, RUK
HAD uses??? switch to EOM if the seeker drops lock.
LOR uses RUK
HAD uses all, depending on how the target was acquired.thanks for the info. is it safe to assume there is no self-defense type of mode implemented in BMS?
If STPT were place every 30nm RUK could be used as LOR. Just beware of the off-bore shot. The SAM will win the race. Not a great workaround <shrug>However, the SAM are not nasty enough in BMS to need a SP mode. imo</shrug></shrug>