Air to Air Missile Flight Physics and Logics, Take two!

[GGTharos]

Spawned from the Ka-50 thread, a discussion on missile physics and logics.

 

First, I'd liek to know ... SK, does minizap model drag properly? I get the same range for high to high shots and high to low shots ... well, approximately the same, anyway.

 

Secodly, Rmax for a missile fired from about 2000 meters to 13000 is about 8nm (16km or so) ... rmax for a missile fired from 13000 to 2000 is about 40nm (for an amraam that is). This doesn't seem to be reflected in LOMAC, but I could be wrong - it seems that it is more advantageous to take low to high shots than the other way around.

 

Lofting is now implemented in 1.1, but it loosk liek the trajectory is not the most optimal ... I thinkt he missile should stil actually loft when fired high to low. Right now, the missile won't exactly 'loft' ... it will jsut not dive as hard against a long range low-flying target. It is my opinion that it should loft and dive to intercept the 'intercept point' at a 30 to 45 deg angle, to maximize its velocity.

 

I also think that active missiles, when supported, should go active at about 10 to 13 sec before impact, and not before ...

[Dark_Sceptre]

I also think that active missiles, when supported, should go active at about 10 to 13 sec before impact, and not before ...

 

I guess the timing of when the missile goes active is a direct function of distance, ie at what point the onboard radar is within range of the target. I would not know this for a fact, but my guess would be that the Time to Active depends not only on the range when firing but also the relative velocity of the target - nose hot will close to active range faster than nose cold. And time after aftive will also be shorter in a headon shot than a tail chase.

 

The only comparison I have at hand, F4, has the missiles going active at around 13s before projected impact in a nose-on shot so I agree that 10-13s sounds plausible

[GGTharos]

It's not 'range based' but rather time based, since range changes with closure :)

 

You're essentially saying the same thing though :)

 

The idea is to give the enemy the minimum time possible for evasion - this should work ebtweenfor F-15 with TWS, but will also work well for MiG-29 with an STT lock.

[SwingKid]

Re: Air to Air Missile Flight Physics and Logics, Take two!

 

First, I'd liek to know ... SK, does minizap model drag properly? I get the same range for high to high shots and high to low shots ... well, approximately the same, anyway.

 

The drag is modelled about as accurately as I can presently imagine making it (i.e. "probably roughly approximately" properly), and to attain this level required modelling four or five different kinds of drag fairly separately. Even a professional simulator can't do it perfectly.

 

Going from high to low, a lofted missile using the glide logic will "pull out" of its dive into horizontal flight at a lower altitude and in denser air. So there is a trade-off between the energy gained by reducing altitude, and the energy lost to friction. Note that the slant range is also longer for such shots than is indicated by the computed Rmax, which only measures horizontal range.

 

Secodly, Rmax for a missile fired from about 2000 meters to 13000 is about 8nm (16km or so) ... rmax for a missile fired from 13000 to 2000 is about 40nm (for an amraam that is). This doesn't seem to be reflected in LOMAC, but I could be wrong - it seems that it is more advantageous to take low to high shots than the other way around.

 

Well, as you and I both know, the missile physics in Lock On is fairly scripted and does not use a sophisticated force-based model. If it was up to me, I would change it, but... :wink:

 

Lofting is now implemented in 1.1, but it loosk liek the trajectory is not the most optimal ... I thinkt he missile should stil actually loft when fired high to low. Right now, the missile won't exactly 'loft' ... it will jsut not dive as hard against a long range low-flying target.

 

As above. Scripted, but perhaps better than no loft at all...

 

It is my opinion that it should loft and dive to intercept the 'intercept point' at a 30 to 45 deg angle, to maximize its velocity.

 

Not sure about this... attacking in a dive presents several design challenges due to look-down, shortened range and other issues. I've never actually seen or read an official source about a missile working this way, it might coast out of the loft into horizontal flight first, like the Nike Hercules.

 

-SK

[GGTharos]

Yeah, the problem with the Nike Hercules example si that it's against a high altitude high speed target :/.

 

It'd be nice to find exmaples or some sort of high to low segment.

 

I don'tt hink look-down in a very big issue, depending on the actual taret altitude. Eg. a target at 10000 feet or so, you probably won't get huge intercerence from looking down given that the ARH seeker isn't all the powerful ... SARH is probably not much different since the illumination doesn't come from straight up, but you'd need a shallower angle. IMHO.

[Sharpshooter]

Here is my take on Lock On missile logic:

 

The Datalink should be also removed from the R-24T. My sources indicate that the only IR missile with Datalink is the R-40T Acrid carried on the Mig-25 and Mig-31.

 

Also I`ve noticed that the R-33E performance is very bad, it hardly hits a fighter plane, even if it is in level flight, the only thing the fighter pilot has to do is dispense some chaff and the missile will be decoyed. So much for the powerful radar of the Mig-31 and it´s predilected weapon. But I´m saying this with no source backup.

 

I´ve noticed that ARH missiles trigger RWR alarms on both NATO(R-77) and Russian Aircraft(AIM-120C). According to my sources and Falcon 4 ARH missiles guide on Datalink until they go Active and then they can be detected by the RWR. Still the question is if the RWR on Russian Aircraft will be triggered because the RWR(SPO) will detect an airborne radar and not a typical signal fighter radars send to targets for guiding SARH missiles. On the other hand F-15C RWRs will detect an active missile radar an will crearly display it on the RWR (I think the F-15Cs RWR is advanced enough to do that, F-16s RWRs can).

 

Moreover if the R-27R and R-27RE have Datalink, wouldn´t they guide on Datalink, and then when the missile is close enough the Fighter Radar will send a signal, so the SARH missile could guide directly to the target ? This will trigger the enemy`s RWR only when fully necessary(ie the missile needs more constant updates so that it can hit the target accurately) and will give him very short notice and thus possibility to evade the missile.

 

Also I would like to know your opinion of implementing on older version of the AIM-120:

 

I feel that AIM-120 early versions should be considered. According to this source: http://www.designation-systems.net/dusrm/m-120.html AIM-120A was the one deployed in 1991 in small quantities and was not fired during the War. It was not until late 1994 that AIM-120B was deployed and AIM-120C earlier version where first deployed in 1996. Futhermore AIM-120C has about 7 subversions, and the earliest should be considered the ones modeled in LOMAC. Since from version to version the AIM-120 has been considerably improved, several versions should be modeled in LOMAC especially for earlier conflicts against missiles such as R-27R and R-27T. Otherwise Su-27 and MIG-29A are in big disadvantage against AIM-120C fitted F-15Cs. At least I reccomend modelling AIM-120 A, B and an early C version, considering that the C version is way better than the B and A versions according to my source.

[SwingKid]

Otherwise Su-27 and MIG-29A are in big disadvantage against AIM-120C fitted F-15Cs.

 

I think the disadvantage only exists insofar as the "advanced capabilities" of the later versions are actually modelled.

 

-SK

[Sharpshooter]

Otherwise Su-27 and MIG-29A are in big disadvantage against AIM-120C fitted F-15Cs.

 

I think the disadvantage only exists insofar as the "advanced capabilities" of the later versions are actually modelled.

 

-SK

 

I particulary consider the AIM-120C as an Advanced version. Even if it is the AIM-120C-1. The R-27RE entered service according to the 1.1 Manual in 1985, and the AIM-120C-1 entered service in late 1996 according to the link I posted. I think that if ED labeled it AIM-120C it is because they modeled it at least to the earliest AIM-120C that entered service. The AIM-120C has numerous advantages compared to the AIM-120B and A, including better countermeasure resistance, and in Lock On it is practically inmune to it. But, still there is confusion. The AIM-120 in Lock On is labelled AIM-120C but the model is an AIM-120A or B. You see the AIM-120C has clipped, ie shortened, wings and fins as seen in this photograph: http://www.designation-systems.net/dusrm/aim-120c.jpg This allows the missile to be fitted in the internal bays of the Raptor.

 

I think I exaggerated a bit with it being a big disadvantage because the Russian Fighters still have range advantage, but I still think that it leaves them in inequality.

[GGTharos]

Have you been playing this game? ... The AMRAAM ain't all its cracked up to be in this game ;)

[D-Scythe]

and in Lock On it is practically inmune to it

 

Don't know what game you've been playing, but in Lock On, the AIM-120 is far more susceptible to decoys than it should be. SARH missiles are virtually immune to chaff in Lock On - provided that you can keep your radar locked up, that is ;)

[Sharpshooter]

I do not know what do you do, but I have far more success beaming, outmaneuvering or outrunning the AMRAAM than decoying it with chaff. If anything the AMRAAM tracks, that is what it is best at, I have never seen the AMRAAM drop a target, only running short or failing to detonate near the target. But being decoyed by chaff, never, and I have tried.

[D-Scythe]

Boot up the FBP, set range to medium, set an AI F-15C vs. an AI Su-27, and watch the two duke it out. I guarantee that the AIM-120 would be decoyed at least once while tracking the Su-27, but chances are that the missile will re-acquire soon enough to kill it. Against human pilots, there would almost be no chance of reacquisition by the AMRAAM, as by then smart guys know how to extend far enough away from the missile to render it useless.

 

If you don't fly the F-15, don't say that the AIM-120 is some uber missile. It isn't (although it should be very close IRL, like the R-77), and this is coming from a guy that has fired just as many R-77s as AIM-120s ;)

[Guest ruggbutt]

I have a client that is an instructor for F-16's. We've spent hours talking about a/c and I've asked him questions regarding the 120 and the sim. He can't divulge classified info, but he has stated that in most of our discussions of the 120 w/in the sim, that the 120 is undermodeled. He smiled at me once and said "you'd be surprised at the real world performance, it's a killer". He also asked if we had any other radar modes besides RWS, STT and TWS. He said there's an intermediate mode that is like STT but updates other targets, IIRC he called it SAM or SAW.

 

I really don't know where I'm going w/this, as the "real" 120 info is classified. I guess I wanted to make the point that according to a pilot who has fired 120's, they're undermodeled in this sim.

[D-Scythe]

SAM - Situational Awareness mode or something. Falcon 4 had it.

[Sharpshooter]

I did what you said, if the AMRAAM is decoyed by any chaff it is unnoticeable it instantly reacquires. In that setup the F-15C always wins, at least the 5 times I tried it did.

 

I know how to fly every plane in LO:MAC and though I may not be as skilled as a dedicated pilot I know well the ups and downs of almost every aircraft. I have flown the F-15C and I have always beat the Flanker, the AI just does not have any good tactics against it and chaff seems to do nothing for them as they do nothing for me. I have not dogfighted against a human player nor did an F-pole Fight ini the F-15C. This is coming from someone how fires AIM-120s and from one that is constantly trying to dodge them, though I still deploy chaffs. The AMRAAMs that I can dodge, are launched outside the "no escape" zone. The ones launched in the no escape zone require better tactics and there is a slim chance that you will dodge them. Perhaps you could hint me on how to evade an AMRAAM with chaff, maybe I will learn something new.

 

I can understand how the SARH missiles are not decoyed easily by chaff, because the seeker is searching for an especific signal and it will not be mislead easily by huge RCS. ARH in contrast are searching for an specific target in an area, with maybe an specific RCS passed on by the launching platfofrm. I can understand how that missile could be decoyed by a huge RCS. But I am just firing blind on this one.

[GGTharos]

rugg, /all/ missiles in this game suffer from the same problem ... poor missile ballistics modelling. I convincned myself of that a little while ago, and SK seems to agree. ;)

 

I think once those are properly modelled you will indeed find the AIM-120 to be quite the 'killer' ... the R-77 matches it, but just barely, and that's only balistically - electronics are another thing altogether.

 

In addition the missile guidance logics are pretty simplified ...

 

Anyway, ED is looking at addressing all this which is a good thing. Hopefully we can get an upgraded if not overhauled missile physics model, and some good guidance logic as well.

[Sharpshooter]

I have a client that is an instructor for F-16's. We've spent hours talking about a/c and I've asked him questions regarding the 120 and the sim. He can't divulge classified info, but he has stated that in most of our discussions of the 120 w/in the sim, that the 120 is undermodeled. He smiled at me once and said "you'd be surprised at the real world performance, it's a killer". He also asked if we had any other radar modes besides RWS, STT and TWS. He said there's an intermediate mode that is like STT but updates other targets, IIRC he called it SAM or SAW.

 

I really don't know where I'm going w/this, as the "real" 120 info is classified. I guess I wanted to make the point that according to a pilot who has fired 120's, they're undermodeled in this sim.

 

Could you tell us when he started flying the F-16, what version of the F-16 or what type of AMRAAM he talks about ? I´m not argueing that the AIM-120C is not a killer, I´m saying that the AIM-120A version should be modeled. With all the updates the AIM-120 got I have no doubt it´s a hell of a missile, but maybe it is a hell of a missile -now- or five years ago, but how about 15 years ago ?

[GGTharos]

It was a hell of a missile before it went to production. It's first test almost had it fail, next test they had fixed all the problems and saw an F-15 destroy 4 targets simulltaneously at various altitudes, maneuvering, non maneuvering and jamming.

 

So the 120C would be a virtual death ray ;)

(And every time I say that, I get laughed at by thte real pilots, but its ok ;) )

[D-Scythe]

I can understand how the SARH missiles are not decoyed easily by chaff, because the seeker is searching for an especific signal and it will not be mislead easily by huge RCS. ARH in contrast are searching for an specific target in an area, with maybe an specific RCS passed on by the launching platfofrm. I can understand how that missile could be decoyed by a huge RCS. But I am just firing blind on this one.

 

No. The interaction between an active radar missile like the R-77 or AIM-120 and the launching platform is a lot more complicated and precise than that, especially if the jet guides the missile all the way to the point it goes active. If lock is lost, then yeah, that might be an issue, BUT considering that with an SARH missile which will go ballistic without a lock, a fail to see how an SARH missile can in any way out-perform an AMRAAM or R-77 by as much as they are doing now in Lock On.

 

GG, I wished I shared your enthusiasm, but I don't. Missile ballistics might be modelled more accurately after V1.1, but I don't think the AIM-120 will ever be at a level it should be. There was already an outcry that they turned the AIM-120 into a deathray right after the 1.02 patch (of which it definitely was not) from the MiG and Flanker drivers.

[Sharpshooter]

SAM - Situational Awareness mode or something. Falcon 4 had it.

 

It is a submode of RWS, it works like this: You scan on RWS see a target designate it and you will get the targets vector, and launch information, while the radar keeps scanning for targets in RWS. Designate it again and you enter STT.

[GGTharos]

I can understand how the SARH missiles are not decoyed easily by chaff, because the seeker is searching for an especific signal and it will not be mislead easily by huge RCS. ARH in contrast are searching for an specific target in an area, with maybe an specific RCS passed on by the launching platfofrm. I can understand how that missile could be decoyed by a huge RCS. But I am just firing blind on this one.

 

No. The interaction between an active radar missile like the R-77 or AIM-120 and the launching platform is a lot more complicated and precise than that, especially if the jet guides the missile all the way to the point it goes active. If lock is lost, then yeah, that might be an issue, BUT considering that with an SARH missile which will go ballistic without a lock, a fail to see how an SARH missile can in any way out-perform an AMRAAM or R-77 by as much as they are doing now in Lock On.

 

GG, I wished I shared your enthusiasm, but I don't. Missile ballistics might be modelled more accurately after V1.1, but I don't think the AIM-120 will ever be at a level it should be. There was already an outcry that they turned the AIM-120 into a deathray right after the 1.02 patch (of which it definitely was not) from the MiG and Flanker drivers.

 

Yeah, a whole bunch of the MiG and Flanker drivers also think that the F-15's specs were taken solely form advertizing material, whihch is why it 'performas so well', so, pardon me for being harsh but, I don't think much of their ... uh, thinking.

 

Now that they've learned to beat the 120, they started whining about the fact that ECM works against them now. I know, we won't get -everything- for the AMRAAM, but improved missiles ballistic -alone- would be a great change in the game that would require more proper fighter tactics to be used, regardless of seeker performance etc.

Chizh mentioend that they are looking into seeker performance ... modelling changes for SARH and ARH in 1.2, so hopefully the ballistics will also be addressed to some degree.

[Guest ruggbutt]

Could you tell us when he started flying the F-16, what version of the F-16 or what type of AMRAAM he talks about ?

 

We talked about all the versions. He stated that the A model has a couple of "idiosyncracies" concerning what had to be done to launch one, but he refused to go into detail, as there are still A models in the inventory. He stated that the old models were fantastic, just had the "idiosyncracies" that he wouldn't extrapolate on. He said the newest versions were out performing the old ones by quite a margin, but that the modeling we have didn't seem to be representative of the first "A" model. He flew F4's before he flew F16's, so I don't know how long he's been flying, and he was in the first Gulf War. Seems he's more important to the brass training new pilots now.

 

I spoke to him at length about the community here. He was impressed that we all know about notching, beaming, WEZ, PK, etc. He said he'd love to get me and a couple of guys up in a '16 and he thought that we'd do very well. He said his students have a hell of time w/instruments and simulators. I told him the story about how I finally figured out how to calculate the heading needed to properly beam an opponent. I explained that I used to do the addition or subtraction before I realized the HSI was there to "do the math" for me. He laughed at length and stated that a couple of weeks ago he had explain to his students the exact same process. He also said that he'd probably suck bad if he tried to fly any of the sims on the computer as they have no tactile input. He said he can feel what the airframe is doing, and what he can do just by the G's on his body. I'm thankful that this guy is a fantastic human being and that when he has time that he'll chat w/me. I thank him often for that and for his service.

 

I'm going to put a bunch of LOMAC vids on a DVD for him so he can see what "fun" we have. He was also impressed w/the TrackIR technology. He had no idea that was available.

[Sharpshooter]

No. The interaction between an active radar missile like the R-77 or AIM-120 and the launching platform is a lot more complicated and precise than that, especially if the jet guides the missile all the way to the point it goes active. If lock is lost, then yeah, that might be an issue, BUT considering that with an SARH missile which will go ballistic without a lock, a fail to see how an SARH missile can in any way out-perform an AMRAAM or R-77 by as much as they are doing now in Lock On.

 

GG, I wished I shared your enthusiasm, but I don't. Missile ballistics might be modelled more accurately after V1.1, but I don't think the AIM-120 will ever be at a level it should be. There was already an outcry that they turned the AIM-120 into a deathray right after the 1.02 patch (of which it definitely was not) from the MiG and Flanker drivers.

 

Of course the interaction is more complicated, but as it is more complicated is more classified that info so we are speaking in general terms. I don´t know about SARH missiles outperforming ARH missiles but I know that due to the method employed to guide the missile to the target they should have more natural resistance than ARH to chaff. The AMRAAM had to be updated against contermeasures like a thousand times, so it could not have been a killer missile all the way, it went through a process that took it there. You are not born invincible but made. The test could have gone perfectly, but the real world and the real targets are not the same as drones, if they were you´ll still have the AIM-120A in production.

 

 

Yeah, a whole bunch of the MiG and Flanker drivers also think that the F-15's specs were taken solely form advertizing material, whihch is why it 'performas so well', so, pardon me for being harsh but, I don't think much of their ... uh, thinking.

 

Now that they've learned to beat the 120, they started whining about the fact that ECM works against them now. I know, we won't get -everything- for the AMRAAM, but improved missiles ballistic -alone- would be a great change in the game that would require more proper fighter tactics to be used, regardless of seeker performance etc.

Chizh mentioend that they are looking into seeker performance ... modelling changes for SARH and ARH in 1.2, so hopefully the ballistics will also be addressed to some degree.

 

I´d really like missile ballistics implemented as well as the AFM, and I want it even more than modelling AFM on all flyables. But the best would be if they can model the seekers in a less scripted way.

 

I´m against ED getting the 120C better it´s already killer, I get only but kills in no escape zone. I personally think they should model AIM-120A, it´s the best way to balance Flanker, and MIGs against the F-15C. The 120C would be used against MiG-29S fighters. Otherwise the mission maker has no choice but the 120C and the older fighters with older missiles are somewhat behind the mighty 120C.

 

I think F-15Cs FM is fine, I really don´t know nothing about that subject realistically, but at least it is not overwhelming nor behind the Russian Fighters.

[GGTharos]

No, the seekrs /all/ have their problems ... but the ballistics ar e/more/ important right now ebcause the way they are modelled at this moment do -not- at all force you to use realistic tactics, -period- , and the seekrs have zippo to do with it. I'm -very- serious about this and I can easily back up this statement. And I'll tell you right now I can beat the 120 as easily as any other missile in the game.

[Sharpshooter]

No, the seekrs /all/ have their problems ... but the ballistics ar e/more/ important right now ebcause the way they are modelled at this moment do -not- at all force you to use realistic tactics, -period- , and the seekrs have zippo to do with it. I'm -very- serious about this and I can easily back up this statement. And I'll tell you right now I can beat the 120 as easily as any other missile in the game.

 

Of course all the seekers have their problemas SARH and ARH, otherwise why would there be upgraded seekers ?

 

Even if seekers don´t have to do anything with that, I would like to see a more natural effect on missile logic, not just, you know, scripting 5% chance that the missile will eat some chaff. Also I would like radar locks lost to chaff, I`ve been told that this happens.

 

If you can back up your statement, what are you waiting for ! You know I will ask you everytime, if I talk I specify my sources (except if common knowledge) otherwise I specify that I don´t.