GGTharos Posted November 6, 2005 Posted November 6, 2005 I think there are multiple reasons for the 120's higher Pk. One of them is probably timing of the missile going active - I think, from what I've read, it doesn't go active in the ideal cases until it's but some 13-15 sec away from intercept, in which case reaction time is quite minimal - possibly not even enough to actually accomplish a beam. The LOMAC 120 behaves quite differently, which can result in a 20 second warning time from when it goes active. Those few seconds are extremely significant. Additional contributors may easily be what we discussed, and who-knows-what-else. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
Prophet_169th Posted November 6, 2005 Posted November 6, 2005 I was just talking about this on our TS server the other night. Even when pressing a bandit, and keeping lock, the 120 seemed to have poor Pk. I hadnt even read this thread. But I dont mind so much, it gives the SU27/33 a bit less of a disadvantage against the 120 spammin F15 =).
D-Scythe Posted November 6, 2005 Author Posted November 6, 2005 I was just talking about this on our TS server the other night. Even when pressing a bandit, and keeping lock, the 120 seemed to have poor Pk. I hadnt even read this thread. But I dont mind so much, it gives the SU27/33 a bit less of a disadvantage against the 120 spammin F15 =). An F-15 wouldn't have to spam if the AIM-120 was modelled properly ;)
Alfa Posted November 7, 2005 Posted November 7, 2005 Just remembered.... I wrote, ...So all I can do is really to suggest Lock-on servers to adopt a mod to correct this issue - perhaps integrated into Shepski´s realistic payload mod. I just remembered that the 6x R-77 modification for the MiG-29S is already integrated into Shepski´s V1.1 realistic payload mod. When I wrote his custom A-10 payloads into the meinit, I also made the following changes to the MiG-29S entry: - made all 6 pylons compatible with the R-77 - changed stock payload containing 6x R-60M to instead contain 6x R-77 One of these days I may have to let Shepski in on this too.....LOL. I cannot believe I forgot all about it - must be getting senile. So any lock-on server that contemplates introducing 6x R-77 capability for the MiG-29S can simply adopt Shepski´s realistic payload mod for the purpose - and get a whole lot of extra payloads for other aircraft in the bargain :) Just a suggestion :) Cheers, - JJ. JJ
SwingKid Posted November 7, 2005 Posted November 7, 2005 One more thing SK. By your logic, there shouldn't be much of a difference between the AIM-7F and the AIM-7M...but there is, and it's huge. Whoa, missed this comment. Why by my logic? AIM-7M uses a monopulse seeker, AIM-7F conical scan. I would would say that IS huge. It also has command inertial, boost-sustain motor and other improvements that have little to do with processor speed. Take all those away, but let it keep the computer, and IMHO you have little difference from AIM-7F at all. -SK
Pilotasso Posted November 7, 2005 Posted November 7, 2005 Whoa, missed this comment. Why by my logic? AIM-7M uses a monopulse seeker, AIM-7F conical scan. I would would say that IS huge. It also has command inertial, boost-sustain motor and other improvements that have little to do with processor speed. Take all those away, but let it keep the computer, and IMHO you have little difference from AIM-7F at all. -SK Of course it is, poke an eye out, and you have a lot less to feed the brain... We should be carefull in generalizing. .
Pilotasso Posted November 7, 2005 Posted November 7, 2005 I think there are multiple reasons for the 120's higher Pk. Another thing to take in account is that In LOMAC we fly shorter missions and use afterburn and demand high G's more often than real aircraft in combat. Naturaly if your missile is well represented the PK will be somewhat lower. .
D-Scythe Posted November 7, 2005 Author Posted November 7, 2005 Whoa, missed this comment. Why by my logic? AIM-7M uses a monopulse seeker, AIM-7F conical scan. I would would say that IS huge. Sorry, lol, I didn't mean it the way it sounded. We were discussing missile guidance computers/avionics, and I meant that basically the AIM-7M was able to use a monopulse seeker because guidance technology/software allowed it to, not the other way around. It also has command inertial, boost-sustain motor and other improvements that have little to do with processor speed. Take all those away, but let it keep the computer, and IMHO you have little difference from AIM-7F at all. -SK The seeker and the guidance section are linked in this way, so you can't "split" them apart. Even if you can argue that by taking everything away from the AIM-7M except the computers/software basically gives you an AIM-7F, how do you explain the transition from the AIM-120A to the AIM-120B/C (C is just a B with clipped wings)? The only difference between the A and the B/C is *just* the computers. Nothing else.
D-Scythe Posted November 7, 2005 Author Posted November 7, 2005 Another thing to take in account is that In LOMAC we fly shorter missions and use afterburn and demand high G's more often than real aircraft in combat. Naturaly if your missile is well represented the PK will be somewhat lower. What if the Pk is *over*represented (i.e. AIM-7 and R-27)? Not by a little either....by some 200%.
Pilotasso Posted November 7, 2005 Posted November 7, 2005 What if the Pk is *over*represented (i.e. AIM-7 and R-27)? Not by a little either....by some 200%. Well 200% is a litle over the top , since I doubt we demand twice as much from the fighters as real pilots do. IF we ever got the R-27 to correct statistical PK we would have alot of players dropping from the russian birds. We would be forced to hope for a sim with the most advanced Mig/Su variants. .
SwingKid Posted November 7, 2005 Posted November 7, 2005 Even if you can argue that by taking everything away from the AIM-7M except the computers/software basically gives you an AIM-7F, how do you explain the transition from the AIM-120A to the AIM-120B/C (C is just a B with clipped wings)? The only difference between the A and the B/C is *just* the computers. This is entering the realm of things I'm probably not supposed to know about, but basically, "AFAIK" - the "loft" mode was basically not working on the early AIM-120A, making it almost a dud missile as a result, with a reduced range compared to AIM-7M. They tried to add a loft flight profile but it kept undershooting its targets. The trouble is that the AIM-120 is a dynamically unstable missile, allowing it to have lighter weight, smaller control surfaces, smaller power requirements and thus contain more fuel etc. instead of batteries and control surface actuators, but a dynamically unstable airframe requires a flight computer and advanced software to fly. The AIM-120B didn't introduce a new computer so much as it introduced re-programmability. The predicted, simulated flight trajectories were simply not matching what was happening in the tests, so the flight trajectory had to be constantly re-programmed and tailored bit-by-bit as a result of experimentation. The R-77, also a dynamically unstable missile, also required a reprogrammable computer. The new computer of the AIM-120B finally allowed the loft flight profile to be ironed out, and it started appearing in AMRAAM manuals somewhere in the late 90s. This finally gave the AMRAAM range performance that could compete, and even beat, the AIM-7M. The Lock On AIM-120 (and the Jane's F/A-18 AIM-120) was initially designed based on unclassified data from the earlier, loftless AIM-120A, and for this reason it had initially a shorter range than AIM-7 in these sims. So maybe this is splitting hairs, but I think all the new hardware and software has only just managed to let the AIM-120 "catch up" to (and ok, now finally surpass) the much better-matured technology that was already available in AIM-7M, that was able to optimize its own flight profile without such advanced equipment, simply by virtue of being dynamically stable. So, "yes and no" - those advanced computers and software make the AIM-120 a better missile, but they alone wouldn't help the AIM-7M at all. The main motivation for those advances was to compensate AIM-120-specific deficiencies, rather than to further advance a superior design. End "speculation." ;) -SK
britgliderpilot Posted November 7, 2005 Posted November 7, 2005 Well 200% is a litle over the top , since I doubt we demand twice as much from the fighters as real pilots do. IF we ever got the R-27 to correct statistical PK we would have alot of players dropping from the russian birds. We would be forced to hope for a sim with the most advanced Mig/Su variants. IIRC, the "correct statistical" warshot PK for the R27 . . . . . is 0% ;) I haven't seen any other representative data . . . . anyone? http://img.photobucket.com/albums/v121/britgliderpilot/BS2Britgliderpilot-1.jpg
Gazehound Posted November 7, 2005 Posted November 7, 2005 IIRC, the "correct statistical" warshot PK for the R27 . . . . . is 0% ;) I haven't seen any other representative data . . . . anyone? As far as representative data goes.. there are none for any missile outside its classified testing data, thankfully there havent been enough missiles fired in history for even the most giddy statistician to calculate a sensible ratio. VVS504 Red Hammers
SwingKid Posted November 7, 2005 Posted November 7, 2005 As far as representative data goes.. there are none for any missile outside its classified testing data, thankfully there havent been enough missiles fired in history for even the most giddy statistician to calculate a sensible ratio. Have you read "Clashes"? -SK
D-Scythe Posted November 7, 2005 Author Posted November 7, 2005 This is entering the realm of things I'm probably not supposed to know about, but basically, "AFAIK" - the "loft" mode was basically not working on the early AIM-120A, making it almost a dud missile as a result, with a reduced range compared to AIM-7M. They tried to add a loft flight profile but it kept undershooting its targets. A dud missile? AFAIK, the AIM-120A worked fine without loft. It debuted in combat by going 3 for 3 over Iraq and Bosnia...a PK of 100%. The AIM-7M debuted in DS with a PK of 35% or so. The trouble is that the AIM-120 is a dynamically unstable missile, allowing it to have lighter weight, smaller control surfaces, smaller power requirements and thus contain more fuel etc. instead of batteries and control surface actuators, but a dynamically unstable airframe requires a flight computer and advanced software to fly. The AIM-120B didn't introduce a new computer so much as it introduced re-programmability. The predicted, simulated flight trajectories were simply not matching what was happening in the tests, so the flight trajectory had to be constantly re-programmed and tailored bit-by-bit as a result of experimentation. The R-77, also a dynamically unstable missile, also required a reprogrammable computer. What about the AIM-120C1/2/3/4/5/6 upgrades, which were mostly to the missiles' guidance software? The new computer of the AIM-120B finally allowed the loft flight profile to be ironed out, and it started appearing in AMRAAM manuals somewhere in the late 90s. This finally gave the AMRAAM range performance that could compete, and even beat, the AIM-7M. The question was never whether the AIM-120 can match the AIM-7M in range, it's why doesn't the AIM-120 have a better pK like its supposed to. Sure, the Sparrow might be superior kinematically to initial versions of the AMRAAM, but you can defeat a missile without kinematics through chaff and ECM. The Lock On AIM-120 (and the Jane's F/A-18 AIM-120) was initially designed based on unclassified data from the earlier, loftless AIM-120A, and for this reason it had initially a shorter range than AIM-7 in these sims. Jane's F/A-18's AIM-120 had a MUCH greater range than the AIM-7M/H. So maybe this is splitting hairs, but I think all the new hardware and software has only just managed to let the AIM-120 "catch up" to (and ok, now finally surpass) the much better-matured technology that was already available in AIM-7M, that was able to optimize its own flight profile without such advanced equipment, simply by virtue of being dynamically stable. Again, that would simply be the autopilot controlling the missile (responsible for lofting and such). Much of the AIM-120C's software development was focussed on *guidance,* not autopilot. If for some reason the US decided to replace the AIM-7's guidance section with the AIM-120C's, I wouldn't doubt the AIM-7 would be just as lethal as well. IMO, they haven't done so because it's a matter of cost, not a question of design. They *can* do it, but why have 2 active radar missiles? So, "yes and no" - those advanced computers and software make the AIM-120 a better missile, but they alone wouldn't help the AIM-7M at all. The main motivation for those advances was to compensate AIM-120-specific deficiencies, rather than to further advance a superior design. End "speculation." ;) Heh, speculation :) -SK
Gazehound Posted November 7, 2005 Posted November 7, 2005 Have you read "Clashes"? -SK No, I just googled it - I take it it contradicts me though :D VVS504 Red Hammers
SwingKid Posted November 7, 2005 Posted November 7, 2005 A dud missile? AFAIK, the AIM-120A worked fine without loft. It debuted in combat by going 3 for 3 over Iraq and Bosnia...a PK of 100%. This was not what was paid for. To qualify as a success, it needed to out-range R-27ER. What about the AIM-120C1/2/3/4/5/6 upgrades, which were mostly to the missiles' guidance software? They were? What was deficient in AIM-120C-5 software, and why is AIM-120B still being used then under the same name? I thought these changes were mostly to the fuze and rocket motor fire safety, allowing its safer storage aboard aircraft carriers. The whole "B->C" nomenclature change was over fin dimensions. The question was never whether the AIM-120 can match the AIM-7M in range, it's why doesn't the AIM-120 have a better pK like its supposed to. It appears to be because in these tests, the AIM-120s are having targets illuminated look-down, while the AIM-7M targets are being illuminated look-up. Give the AIM-7M the same ground clutter problem, or shoot at higher-altitude targets with the AIM-120, and the AIM-120 should beat the AIM-7. Jane's F/A-18's AIM-120 had a MUCH greater range than the AIM-7M/H. With AIM-7 using loft, and AIM-120 not using loft? Odd, but ok, I didn't realize that. Again, that would simply be the autopilot controlling the missile (responsible for lofting and such). Much of the AIM-120C's software development was focussed on *guidance,* not autopilot. The loft trajectory is extremely dependent on knowing target range. The air up there is so thin the missile is flying ballistically and is unable to maneuver or generate lift until it descends back down to thicker air, by which time it already needs to be pointing at the target. So, I don't think we should separate the two. If "guidance" only means "terminal PN homing trajectory" - well that part was already working many decades ago. What does it do, pull lead better? If for some reason the US decided to replace the AIM-7's guidance section with the AIM-120C's, I wouldn't doubt the AIM-7 would be just as lethal as well. How does it resolve a look-down target against the background of the earth, if not by pulse-Doppler that requires a Doppler shift? I don't think guidance computers are yet so advanced that they can change the laws of physics to own advantage. -SK
tflash Posted November 7, 2005 Posted November 7, 2005 Very interesting info, Swingkid. I am a little surprised though with the range comparison between AIM-7M and AIM-120. I always thought AIM-120 was meant really to be a *medium* range missile, optimized to be deployable in a larger *usefull* range span then the AIM-7M. I thought that one of its advantages is that is works fine from relatively short ranger to the higher end of medium range, whereas a AIM-7M was optimized as a true interceptor missile, optimized for a real "longbow" loft shot in BVR at relatively unmanoevrable soviet bombers. In this sense it was a weapon of choice for Tomcat and Tornado F-3 (Skyflash). In my opinion the AIM-120 was supposed to return to the AIM-7E-2 dogfight Sparrow philosophy, being more manoevrable in a wider envelope. I would compare AIM-120 to missiles like MICA, that you can use from short range to medium range. This would also explain why often an all-amraam load is carried by vipers and eagles, since the amraam also covers a lot of the short range? This would certainly not be possible with AIM-7M. I precisely like the AIM-7M for its strong, straight, lofted, high-energy long range shot. Ideal to shoot an incoming bomber in the face. [sIGPIC][/sIGPIC]
GGTharos Posted November 7, 2005 Posted November 7, 2005 The AIM-7 actually received 'dogfighting' upgrades at some point or another, so it's certainly useful (and has been used) against fighters, but it has a longer 'min range' than the AMRAAM most likely. However my understanding is that the AIM-120 also has a significant (longer than the AIM-9's) minimum range. And, SK, I think there are enough research papers on PN and guidance to show that guidance can always be upgraded in one way or another ;) [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
SwingKid Posted November 7, 2005 Posted November 7, 2005 And, SK, I think there are enough research papers on PN and guidance to show that guidance can always be upgraded in one way or another I recently had a research paper accepted. Today I found a mistake in it. ;) -SK
D-Scythe Posted November 7, 2005 Author Posted November 7, 2005 They were? What was deficient in AIM-120C-5 software, and why is AIM-120B still being used then under the same name? I thought these changes were mostly to the fuze and rocket motor fire safety, allowing its safer storage aboard aircraft carriers. The whole "B->C" nomenclature change was over fin dimensions. I don't think it was a matter of deficiency, but they probably tweaked a few things here or there, added a few more lines of code, to improve end-game performance. In any case, if there were deficiencies, and I knew of them, I certainly wouldn't be able to tell anyone about it ;) About the AIM-120B and C thing, my understanding is that the B is only mostly used by mostly U.S. Allies now. Although I'm sure the -120B is still used by the United States, virtually all the development, research and update work is done on the -120C now. I assume that similar updates were also programmed into the -120Bs in Europe through an equivalent OFP update program like in the U.S., but I'm pretty sure the -120B and the 120C use different software - the 120C has an updated guidance section (i.e. hardware), afterall. It appears to be because in these tests, the AIM-120s are having targets illuminated look-down, while the AIM-7M targets are being illuminated look-up. Give the AIM-7M the same ground clutter problem, or shoot at higher-altitude targets with the AIM-120, and the AIM-120 should beat the AIM-7. The way I see it, the AIM-7M, for whatever reason, is tremendously more resistent to chaff. Sure, the AIM-120C may be in a look down situation, but the angle of descent relative to the horizon would produce some pretty long slant ranges to the ground (and back up). On a 5-7 nm ranged radar, ground clutter shouldn't factor in that much at 5000m, certainly not enough to cause a such a huge difference in Pk between the two missiles. With AIM-7 using loft, and AIM-120 not using loft? Odd, but ok, I didn't realize that. In Jane's F/A-18, or F-15, the AIM-7M did not use loft. I don't even think it used PN. The loft trajectory is extremely dependent on knowing target range. The air up there is so thin the missile is flying ballistically and is unable to maneuver or generate lift until it descends back down to thicker air, by which time it already needs to be pointing at the target. So, I don't think we should separate the two. If "guidance" only means "terminal PN homing trajectory" - well that part was already working many decades ago. What does it do, pull lead better? Maybe this is what we're disagreeing on. I'm seeing guidance as resistance to chaff and ECM - thus, it's not a question about trajectory, at all. I usually refer to those functions (pulling lead, PN, loft, etc.) to the missile's autopilot, which would be linked to the guidance unit so that the two works in concert to fly the missile to the target. How does it resolve a look-down target against the background of the earth, if not by pulse-Doppler that requires a Doppler shift? I don't think guidance computers are yet so advanced that they can change the laws of physics to own advantage. Sorry, I don't understand this question. Don't look-down targets actually have to be relatively close to the ground in order to blend into its clutter? Provided that the target is not "beaming" the radar (from above, in this case), most radars shouldn't have a problem picking up a target at 5000 m, even though they are "looking down"? Slant range to the ground would become a factor here, no? An AIM-120's radar doesn't have that much range in the first place.
Sinner6 Posted November 8, 2005 Posted November 8, 2005 In Jane's F/A-18, or F-15, the AIM-7M did not use loft. I don't even think it used PN. Most of this conversation is out of my depth, but I can be sure of one thing. The AIM-7m in Janes f18 DOES have a loft trajectory available, and this DOES give it a slight range advantage over the AIM-120c in that sim. You can access this mode by pressing the "uncage" button after a target is bugged or locked. Pressing uncage prior to lock puts you in "flood" mode, and pressing it while a jamming target is bugged will put you in HOJ mode. For sure.
D-Scythe Posted November 8, 2005 Author Posted November 8, 2005 Most of this conversation is out of my depth, but I can be sure of one thing. The AIM-7m in Janes f18 DOES have a loft trajectory available, and this DOES give it a slight range advantage over the AIM-120c in that sim. You can access this mode by pressing the "uncage" button after a target is bugged or locked. Pressing uncage prior to lock puts you in "flood" mode, and pressing it while a jamming target is bugged will put you in HOJ mode. For sure. So wait...there IS a loft mode available to the AIM-7, but you have to be in FLOOD mode to do it? Hmm, never knew that. I always fired the AIM-7 as I would an AIM-120C, with an STT lock.
GGTharos Posted November 8, 2005 Posted November 8, 2005 No, you don't have to be in flood. You misunderstood what he wrote. But, I'll make it simpler: When selecting an AIM-7, look at the SMS page. There is a LOFT option enabled for one of the PB's. Use it ;) [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
D-Scythe Posted November 8, 2005 Author Posted November 8, 2005 No, you don't have to be in flood. You misunderstood what he wrote. But, I'll make it simpler: When selecting an AIM-7, look at the SMS page. There is a LOFT option enabled for one of the PB's. Use it ;) Ah, okay. But does the AIM-7M/H fly through PN then? I remember in the Jane's sims the only missile that PN'd was the AIM-120. In Jane's F-15 at least (and I'm pretty sure in JF/A-18 too), SARH missiles and heaters both followed a pure pursuit intercept geometry to their targets. IIRC, you can get Slammer kills approaching 50 nm if you fly fast and high enough in the Jane's sims. It was somewhat overmodelled ;)
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