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AIM-7 Performance


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Once the AIM-7 is in the air im sure the flight dynamics are the same whether launched from an F-15 or F/A-18, i think the difference is in the guiding radar and how it cues the missile. Obviously big differences in the radar modeling between these two airframes in which ED will have to smooth out somehow.

Edit: and F/A-18 radar is very much WIP so time will tell.

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Once the AIM-7 is in the air im sure the flight dynamics are the same whether launched from an F-15 or F/A-18, i think the difference is in the guiding radar and how it cues the missile. Obviously big differences in the radar modeling between these two airframes in which ED will have to smooth out somehow.

Edit: and F/A-18 radar is very much WIP so time will tell.

Well, I don't think that it works this way. The aircraft radar shouldn't guide the missile, it should just illuminate the target. It's the missile itself that calculate the intercept geometry based on the reflection coming from the target.

 

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Edited by catt42
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Well, I don't think that it works this way. The aircraft radar shouldn't guide the missile, it should just illuminate the target. It's the missile itself that calculate the intercept geometry based on the reflection coming from the target.

 

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Which is how i understand his post.

Bottomline is, that the APG-73 is WIP and more detailed than the radarmodel in FC3.

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I've heard ED is redoing the AIM-120 for the F-18, so it will be more realistic than the current F-15 one. I suppose then that the AIM-7 given now to the F-18 is also a new one and not the same as the one on the F-15.

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I found the bug! Its the engine of the missile.

It never reaches MACH 4 nor does it sustain Power for very long.

The engine performance is more akin that of a SideWinder.

 

Edit: It might be the drag that isnt correct as well, in either case the missiles range is WVR.

 

 

This also happens in the Eagle, see for example this video:

 

 

The Sparrow barely accelerates at all after launch.

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Hey Weta.

 

So the 53nmi range comes from the USAF F-4 weapons manual which states that at 40kft at M2.0 vs 40kft M2.0 the missile will have a maximum aerodynamic range of 53nmi. It defines RAero as "the maximum distance a missile can travel while still able to effectively maneuver against a target." This includes the number of g's necessary to perform strategic maneuvers.

 

This means that at the 53nmi intercept point the AIM-7F should have the energy to perform at least a 4g pull for a second to hit the target. This would require the missile to be approximately Mach 1. I'd like to note as this is the 7F, there is no lofting included in this flight profile.

 

^This. Well the document I have references the F-4 and F-15, from 1977. Its not as if the distance an air-to-air missile would have traveled upon reaching the ground is particularly useful information. I tried doing this against both an AI A-50 (set to its top speed) and a Mig-29 (Mach 2+) while doing Mach 2+ myself at 40K. In both scenarios the missile will fall below mach 1 before covering the distance, which is less than launch range considering the closure. The document also lists a 22nm sensor range on a 2m^2 target, but that detail is little more confusing, since the missile guidance section indicates proportional navigation and semi active guidance on continuous wave or pulse doppler. If its not being terminally guided off the rail at max range, the missile will always be inside that range by the time it is guiding on the beam, unless they are accounting for signal strength and/or range from the launch aircraft. That seems to be closely tied to the F-4s radar capability, and the F-15 has a much better radar. In either case launching at less the 30nm should leave plenty of excess energy for intercept. The 40K co-alt M2.0 charts are clearly limited to the 22nm sensor range, while the sea level chart still expects a 20nm intercept at M0.9.

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Yeah Sparrow with F-15 is deadly. There's something wrong with the Hornet radar, I've tried the instant mission 4 hornets against 4 MiG-29, locked one MiG but it switched to other MiG by itself. Well Its still WIP I guess.

 

I think rather that the A/F-18C Sparrow behaviour is just more realistic. The missile was notoriously unreliable - as are other semi-active radar homing missiles like the Matra 530D. Unless you are shooting at AI targets, you should expect a low percentage hit rate with semi-active radar homing missiles, especially against manoeuvring targets with chaff and radar jammers.

 

There is a good reason that the AIM-7 and other semi-active missiles are being phased out.

 

That being said, I was very surprised to make a head-on kill on the 104th multiplayer server the other night with a Matra 530D versus a human-guided F18C. His AIM-7 shot on me was defeated by my evading and dumping chaff, while he flew straight into my Matra. The thing is, I only fired it to force him to evade. It should have missed him because I broke radar contact when evading and the Matra should have gone stupid. Maybe he just flew into it by accident?


Edited by fencible
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Perhaps re-read the OP.

The OP talks about Max range.

 

Quoted max range figures are for a non-manoeuvring target with high closure speed, at high altitude.

 

That's what I reported back on.

 

It's true that if he'd beamed, the missile might not have hit.

 

That's part of the purpose of beaming* - so that where before beaming you were inside the effective** engagement range of the attacking missile, after beaming you're not.

 

That's why the NEZ is the NEZ, because outside that range, the target might defeat your missile by doing something like beaming.

 

There are definitely issues with the missile guidance, but - without wanting to be rude to the OP - expecting to get a hit with a 38 NM launch against a slow target at sea level doesn't bring the conversation forward in any real way.

 

My experience playing around against AI MiG-21 last night while trying to continue a mental transition from the Su-27 was that a launch at somewhere inside 15NM would probably get you a kill regardless of their manoeuvres / chaff.

 

There were occasions where they beamed & dropped chaff and the radar lost lock & the missile went ballistic, but again, that's the intended effect of notching and chaff (the tracks were pretty good at picking up the lock though).

 

 

*(I'm at work and not going to watch your track. maybe the poor guidance caused excessive speed loss, maybe they notched / decoyed you, maybe they were just too far away for the shot you made to hit them if they manoeuvred.)

 

**(Put whichever type of range from max aerodynamic through to anything outside NEZ you want to talk about here)

 

But the target did not react to the missile threat in any way, shape or form. The missile should have been able to get within attack range according to the HUD readout, and it failed utterly to do that.

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I think rather that the A/F-18C Sparrow behaviour is just more realistic. The missile was notoriously unreliable - as are other semi-active radar homing missiles like the Matra 530D. Unless you are shooting at AI targets, you should expect a low percentage hit rate with semi-active radar homing missiles, especially against manoeuvring targets with chaff and radar jammers.

 

There is a good reason that the AIM-7 and other semi-active missiles are being phased out.

 

That being said, I was very surprised to make a head-on kill on the 104th multiplayer server the other night with a Matra 530D versus a human-guided F18C. His AIM-7 shot on me was defeated by my evading and dumping chaff, while he flew straight into my Matra. The thing is, I only fired it to force him to evade. It should have missed him because I broke radar contact when evading and the Matra should have gone stupid. Maybe he just flew into by accident.

 

NO.

 

Matra Super 530D isn’t unreliable, neither is AIM-7M.

 

But some people are still confused by Matra R530 (Mirage III missile) and AIM-7E from Vietnam era.

 

AIM-7M shot during Desert Storm had a pretty good PK. And if the missile is shot at long range and miss it isn’t a reliability problem...

 

If Fox 1 are being phased out it’s for tactical consideration, Fox 3 missiles can be fire & forget and gives the shooter the opportunity to turn back before missile impact and still hit the target.


Edited by jojo

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More importantly 68% PK in real combat is waaaaaay more than what we get right now against cooperative targets, even at low ranges of about 8 to 10nm. The 7M fired by the F-15C or the Super 530 fired by the M2K are doing great, while the 7M fired by the new hornet is absolute garbage. Now this is early access and it will be adressed at some point in the future - but please don't say the current behaviour is normal or realistic.

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More importantly 68% PK in real combat is waaaaaay more than what we get right now against cooperative targets, even at low ranges of about 8 to 10nm. The 7M fired by the F-15C or the Super 530 fired by the M2K are doing great, while the 7M fired by the new hornet is absolute garbage. Now this is early access and it will be adressed at some point in the future - but please don't say the current behaviour is normal or realistic.
I agree.

@fencible : I wasnt talking about real life but how it performed in dcs. The Hornet radar as a guidance is still WIP. Just try instant mission 4 hornets vs 4 MiGs and lock one of MiG that flies in close formation from 20 miles. The radar would switch to other target by itself.


Edited by Oceandar

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More importantly 68% PK in real combat is waaaaaay more than what we get right now against cooperative targets, even at low ranges of about 8 to 10nm. The 7M fired by the F-15C or the Super 530 fired by the M2K are doing great, while the 7M fired by the new hornet is absolute garbage. Now this is early access and it will be adressed at some point in the future - but please don't say the current behaviour is normal or realistic.

 

I don't think we should use the DCS F-15C performance as a bench-mark. I think that the FC3 planes - their radars and missiles - probably over-perform.

 

The Super 530D - well I've only read that it did not perform well - I may be misinformed. As I said, I got a head-on kill with it the other night on 104th server - even though I had turned away from the target and was not painting it anymore. I thought maybe it had an infra-red seeker built in as well as the semi-active guidance, but that is not true, so I don't know what happened. Seemed strange to me, though.

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Based on what I have read in this thread I would say the AIM-7 on the Hornet has a ways to go in the development stage on either the missile, the Hornet's radar, or both. I will launch an AIM-7 at a target only 4 nm away with a fast closure rate and the missile still turns left, right, above or below the target. The only time I break away from my target is if they fire a missile at me. Just have to wait while ED continues to tweak and build things on the Hornet.

 

But since the F-15C has been brought up quite a bit in this thread I have a question. Why in both 2.5 stable version and 2.5 open beta does it show on the main welcome screen at the bottom of that screen below the F-15's "button" (where you can click and set it as your wallpaper) does it say that it is a Beta version?

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I don't think we should use the DCS F-15C performance as a bench-mark. I think that the FC3 planes - their radars and missiles - probably over-perform.

 

 

LOL... I find this quote to be utterly wrong..

 

 

 

First lets look at the f15... It's radar is missing several features that the real jet has. When comparing it to the fc3 SU27 they are literately identical in detection range which is not the case in real life.

 

 

Second, the missiles are not over-performing in any sense for either the Nato or RUS variants. Truth be told they all are under performing. They have unrealistic drag and absolutely horrible proportional and Terminal guidance.

 

 

proportional guidance is plagued with no lofting, high G loading immediately off the rail, continuous over G during any and every slight maneuver the target makes.

 

 

Terminal Guidance is plagued with over eating CMs, going dumb for no apparent reasons, and due to the PN stage lacking in any KE for maneuvering ability.

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If your desired effect on the target is making the pilot defecate his pants laughing then you can definitely achieve it with a launch like that.
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i missed a huge IL tanker plane within a few miles.

i observed the missile and it changes its direction for no reason, loses energy much and target evades it easily

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https://drive.google.com/file/d/17jFGpfatEjUbFChZEER_hMshjjuIgq1K/view

-A declassified doc concerning engagement ranges of the aim-7f

-Note that that the aim-7f doesn't have lofting logic built into the missile.

 

Also, it's been known for a quite some time that small body objects in-game (aka missiles) experience unrealistically high drag as is quite well discussed by IASTAG and a ~80pg document that was written up (sorry can't find the link :( ) when he made his missile mod.

 

https://forums.eagle.ru/showthread.php?t=131806

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I think the radar is OK, but the missiles are heavily WIP as they are still from FC3 era by accuracy but very limited by drag and lacking good guidance.

 

So expect to see longer ranges, but less accuracy and more limited launch parameters.

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I went to test the f18 in multiplayer with the aim-7m missiles, I fired 3 missies on a J-11A at a distance 18 - 13mn none dropped it, result j-11A win X Loss F-18.

I really surprised the performance of 7's and created a simple mission with the full f18 of the 7's and a j-11A, ... after several losses I managed to shoot it at a distance of 5mn ...

Test it too.

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Edit: Regarding more 'normal' M1.2 co-alt/speed launches at 30000' or above, the relative range is close to 25nm. The Raero is close to 30nm.

 

Which is about what it is in game.

 

As mentioned earlier, launching from 12000m at a target 25NM away at 15000m (to get a slight loft), then removing the target with a trigger so the missile goes ballistic, the missile travelled 39 NM before returning to 12000 m, at which point it was travelling at 1100 km/h

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