The AIM-7 Sparrow Missile - Information & Discussion topic

[Flame2512 3,386]

k_stepanovich I just want to say thank you. It's really nice having clear communication directly from a developer.

[David Bowie 1,554]

22 hours ago, k_stepanovich said:

No pulse-doppler radars are available in the game now.

F-4M FGR.2 and T-2 have pulse radars without LD/SD capability instead of their native radar (part of their AN/AWG-10 weapon control system).

It prevents these aircraft from becoming imbalanced espescially after SARH missiles introduction.

Mitsubishi T-2 is not equipped with AIM-7 and latest AIM-9

 

Mitsubishi T-2 need a good radars, Because there is no advantage in the 1.101.0.44  

so I think one of the better missiles and radars is necessary.

[Fireraid233 4,275]

1 hour ago, _David_Bowie_ said:

Mitsubishi T-2 is not equipped with AIM-7 and latest AIM-9

 

Mitsubishi T-2 need a good radars, Because there is no advantage in the 1.101.0.44  

so I think one of the better missiles and radars is necessary.

T-2 never used AIM-7s iirc. But it could make do with a less wonky radar and a missile upgrade.

[Bydaniel857 321]

can anybody explain me this? im very confused if they work correct or not, i was locking a target 20km away and i waited untill he was at arround 7km because if i shot when he was that far away the missile doesnt track and explodes, im a bit confused on how this new missiles work, whats the best range? or altitude for a succesful launch? or what conditions should i found to use them? thanks

[Nicolaser 2,024]

10 hours ago, k_stepanovich said:

 

10 hours ago, k_stepanovich said:

It starts searching its target 2 seconds after the launch.

 

Is that related to the fact that aim 7 are more "dropped" than "fired" ?

[The_Monolith 860]

10 hours ago, k_stepanovich said:

AIM-7 missiles are not a "click to kill" weapon. They have a lot of limitations and require skills.

 

1. AIM-7 doesn't lock on the target before launch. It starts searching its target 2 seconds after the launch. Even if the target was in the search cone of the missile seeker before the launch it may appear outside 2 seconds after the launch. It means that in the same conditions AIM-7 has much greater minimal distance than IR-missiles.

Large minimal launch distance and limited G-capability (due the missile autopilot) mean that AIM-7D/E are not dogfight missiles.

 

2. AIM-7 seeker suffers from ground clutter. Below I used very good source provided by Iron_physik about the AIM-7E/E-2 missiles to illustrate this effect.

 

 

So, in my case even under optimal conditions (maintain lock, high altitude, medium range, target at or above my alt) that have been recommended the missile fails to track and times out after 5 seconds. I fire the missile directly at or a little bit ahead of the target in attempt for it to acquire the lock. Is there another parameter I should be aware of? (Most likely a post launch mechanic?)

 

The random track failures are seemingly *random* and I can't identify a pattern or error that changes whether the missile picks up on the illuminated target.

 

Also thanks for all the explanations. The detail to which the missiles are modeled is surprising accurate and very interesting and undoubtedly more accurate than most other games.

[David Bowie 1,554]

8 hours ago, Fireraid233 said:

T-2 never used AIM-7s iirc. But it could make do with a less wonky radar and a missile upgrade.

Yes i know, I trying to say T-2 need a new AIM-9 or New radar

[The_Monolith 860]

4 minutes ago, Nicolaser said:

Is that related to the fact that aim 7 are more "dropped" than "fired" ?

I would suppose that it drops so it can clear the Phantom's nacelles. I have seen videos of F/A-18 sparrow lanches and they don't drop. Earlier models may have another reason for it though.

[SleeplessGlownes 19]

2 hours ago, Bydaniel857 said:

can anybody explain me this? im very confused if they work correct or not, i was locking a target 20km away and i waited untill he was at arround 7km because if i shot when he was that far away the missile doesnt track and explodes, im a bit confused on how this new missiles work, whats the best range? or altitude for a succesful launch? or what conditions should i found to use them? thanks

I personally fire the Aim-7E at a range of 12km at 5km high (Still testing the range of it under combat conditiion). Aim the aircraft toward enemy/lock and fire the missile, still 50% chance that the missile might not track and explode. of course you can fire at an enemy tail if he is within 4km (got Phantom GR2 at that range) with sparrow.

[Zetaris 267]

From firing them in test flight and from looking at the game files, it seems the AIM-7D/E radar receiver antenna has a 20° field of view:

 

Spoiler

        "receiver": {
          "rcs": 2.0,
          "range": 25000.0,
          "rangeMax": 30000.0,
          "antenna": {
            "angleHalfSens": 10.0,
            "sideLobesSensitivity": -16.0
          }

 

Not sure if it's just me, but using AIM-7s and radar in test flight yields much more consistent results. If one of the AI MiG-15s is flying perpendicular to the missile, it won't track. But, if the MiG if flying away or towards me (even if it's below me at 500m), the missile will work fine.

 

As other people have already said, sometimes AIM-7Es won't track even under supposedly 'optimal conditions'. Anecdotally, I've had a few instances where I fire the AIM-7E at a target that is above me, at high altitude and long range (>7km), and approaching at high speed, but the missile won't track. Also there were one or two times where I climbed vertically (>70° degree climb) against a target at high altitude -- again, AIM-7E wouldn't track. These problems don't seem to occur in test flight.

[Bydaniel857 321]

14 minutes ago, Zetaris said:

These problems don't seem to occur in test flight.

yeah, its a bit weird

[Flame2512 3,386]

8 hours ago, Zetaris said:

From firing them in test flight and from looking at the game files, it seems the AIM-7D/E radar receiver antenna has a 20° field of view:

 

 

I would guess (not had time to test) that like on IR missiles angleMax is the maximum tracking angle. From the testing I've done angleHalfSens does seem to impact the performance of the seeker at tracking targets off the the side, but it is not a hard limit on the angle to target.

 

In this video the target is flying due north (0 degrees) and I fire the missile at a heading of 25 degrees; so at the point the missile acquires a lock, 1.8 seconds later, the angle between the missile's boresight and the target will be >25 degrees.

 

https://i.imgur.com/8lpduEO.mp4

Edited September 4, 2020 by Flame2512

[shanrocks1 383]

I really have problems with the aim-7 where out of my four missiles, only 2 manage to track even when I fire directly at the target, may it be head on or flying away. Not sure if there is Rng involved with the tracking but it seems like it.

[k_stepanovich 326]

 

12 hours ago, Zetaris said:

 

As other people have already said, sometimes AIM-7Es won't track even under supposedly 'optimal conditions'. Anecdotally, I've had a few instances where I fire the AIM-7E at a target that is above me, at high altitude and long range (>7km), and approaching at high speed, but the missile won't track. Also there were one or two times where I climbed vertically (>70° degree climb) against a target at high altitude -- again, AIM-7E wouldn't track. These problems don't seem to occur in test flight.

 

Target may turn after the missile launch and conditions may become non-optimal.

The missile seeker may not find its target because of quick acceleration-deceleration of the target and/or the fighter after the launch. AI-airplanes in Test Flight and in Custom Battles usually maneuver not so agressive and don't fly fast, so it works against them better. We will make wider search range for the target radial speed.

 

4 hours ago, Flame2512 said:

 

I would guess (not had time to test) that like on IR missiles angleMax is the maximum tracking angle. From the testing I've done angleHalfSens does seem to impact the performance of the seeker at tracking targets off the the side, but it is not a hard limit on the angle to target.

 

In this video the target is flying due north (0 degrees) and I fire the missile at a heading of 25 degrees; so at the point the missile acquires a lock, 1.8 seconds later, the angle between the missile's boresight and the target will be >25 degrees.

 

https://i.imgur.com/8lpduEO.mp4

Seeker antenna is mounted on the gimbal. The gimbal is oriented on the target before the launch and remains oriented on this direction (no on the target) before target search start and lock on.

The main beam of the antenna is relatively wide ~10 degrees and the antenna still sensitive outside of these 10 degrees.

[EpicBlitzkrieg87 8,350]

@k_stepanovich are the developers aware that the British Phantoms should have the AIM-7E-2 instead? 

[Bydaniel857 321]

54 minutes ago, EpicBlitzkrieg87 said:

@k_stepanovich are the developers aware that the British Phantoms should have the AIM-7E-2 instead? 

and the F4E/C

[Bydaniel857 321]

4 hours ago, k_stepanovich said:

Seeker antenna is mounted on the gimbal. The gimbal is oriented on the target before the launch and remains oriented on this direction (no on the target) before target search start and lock on.

this means that the seeker always follows the antenna that illuminates the target?

[Flame2512 3,386]

1 hour ago, Bydaniel857 said:

this means that the seeker always follows the antenna that illuminates the target?

Say your radar target is the same altitude as you and 20 degrees to your left. The missile seeker (with a 10 degree FoV) will point itself in the direction of the target (in this example 20 degrees to the left) before launch. After launch the missile will fly in a straight line for 2 seconds and the seeker will continue pointing 20 degrees to the left. After those 2 seconds if the missile can see your radar target within it's 10 degree FoV (the centre of which points 20 degrees to the left of the missile centre line), it will lock onto the target. If it can't see the target then the missile will not obtain a lock and will explode shortly afterwards.

[Bydaniel857 321]

17 minutes ago, Flame2512 said:

Say your radar target is the same altitude as you and 20 degrees to your left. The missile seeker (with a 10 degree FoV) will point itself in the direction of the target (in this example 20 degrees to the left) before launch. After launch the missile will fly in a straight line for 2 seconds and the seeker will continue pointing 20 degrees to the left. After those 2 seconds if the missile can see your radar target within it's 10 degree FoV (the centre of which points 20 degrees to the left of the missile centre line), it will lock onto the target. If it can't see the target then the missile will not obtain a lock and will explode shortly afterwards.

wow, this is very complicated to make it work going to need to practise more

[SirScorpion 1,091]

6 hours ago, k_stepanovich said:

 

Target may turn after the missile launch and conditions may become non-optimal.

The missile seeker may not find its target because of quick acceleration-deceleration of the target and/or the fighter after the launch. AI-airplanes in Test Flight and in Custom Battles usually maneuver not so agressive and don't fly fast, so it works against them better. We will make wider search range for the target radial speed.

 

Seeker antenna is mounted on the gimbal. The gimbal is oriented on the target before the launch and remains oriented on this direction (no on the target) before target search start and lock on.

The main beam of the antenna is relatively wide ~10 degrees and the antenna still sensitive outside of these 10 degrees.

 

 

Please consider ping when coding the missile, lots of missiles suffer, a 100 to 200ms ping should be standard deviation for fuse and missile gates. thank you

[Aerobane 4,140]

I just had something quite interesting happen right now and I wonder if its realistic. I'm in the F104S on Preparation for Landing on Hokkaido, 4xAim9B + 2xAim7E. I kill a phantom early with my first sparrow and manage to escape by outrunning everyone and their missiles on the deck. I turn around and start heading back towards the remaining furball although my team is already pretty much gone. As I'm coming in and still about 12km out one of their mig 21s goes vertical and loops over, becoming a good sparrow target. I lock him up and fire at about 9km:

Note the Jaguar slightly to the right and well below the Mig-21, player "Baile_De_Favela."

 

The missile tracks well and continues to do so until I can no longer see it. The Mig dives down and I am able to maintain lock consistently the whole time. Just as I'm expecting the missile to be hitting, I get a team kill on the friendly jaguar. This screenshot was taken from the moment of impact:

Looking back through the replay, I see that the mig passed in near and slightly in front of the jaguar when the missile was 4km away from them. At that time the sparrow was tracking the mig perfectly, although if he continued his dive a big longer and it hadn't switched targets I think it may have just lawndarted trying to intercept his current path at a point under the ground:

About a second after the two merge and while they are heading in opposite directions, the sparrow abruptly switches target turning to the right and up to intercept the jaguar, despite radar lock on the Mig:

Note the missile in the bottom center and its smoke trail. The Mig-21 was heading in the exact opposite direction of this new course so you can see exactly when it switched targets from the sudden turn.

 

I was totally surprised when this happened because neither the missile nor its smoke trail were still rendering for me and I was looking at the Mig. Even though I wasn't zoomed in, the Jaguar was only barely visible at the top right of my screen. I had no idea where it was when I hit him until I checked the replay. Here is my player's view at the moment of impact:

 

Obviously what I assume happened is that even though the radar was still locked on the Mig-21, it was also illuminating the Jag as well and as they passed near each other the sparrow picked up returns coming from the Jaguar and went after it instead. So my question to the experts, does this make sense? I think it depends how the target illuminating works and how narrow the sector it illuminates is. I can understand it switching targets easily but continuing to track the Jag while the radar was illuminating the mig a solid 10-20 degrees or so off to the left and below is noteworthy. I've never seen this type of behavior in any of my other F-104S games (which is quite a few, I've been having a lot of fun with it.)

 

Anyone had a similar experience? Were there cases of this happening historically? Also, RIP 15k SL.

[TeaParty4622 301]

9 hours ago, Bydaniel857 said:

10 hours ago, EpicBlitzkrieg87 said:

@k_stepanovich are the developers aware that the British Phantoms should have the AIM-7E-2 instead? 

and the F4E/C

British phantoms had internal 7E-2 dogfight mode activation switch.

RAF FG mk.1

And RN FG mk.1

I think FGR.2 had same controls for 7E-2's dogfight mode.

CHECO report says AIM-7E-2 without dogfight mode activated had identical performances of AIM-7E. 

 

So i don't think 7E on current brit phantoms are wrong. And understandable as part of balancing.(Like F-4C having AIM-7D? but F-4C's case is not understandable.)

 

For the game's part, if 7E-2 be introduced to the game, it'll be locked on to dogfight mode configuration performance. 

 

+the ones didn't had that sparrow control switch with their cockpit had to choose and modify which mode of 7E-2 they want to carry on the ground, before the mounting. 

[Aerobane 4,140]

I've just realized what happened to me makes no sense at all. If the radar can effectively illuminate the Mig and the Jaguar at such a wide angle simultaneously, why require radar lock to launch? Shouldn't we be able to just turn on the illuminator, light up everything in front of us, and start spamming sparrows at multiple enemies simultaneously? Because if the radar can illuminate multiple targets simultaneously and illuminate targets that are not locked or close to the target being locked, then it should be able to guide sparrows to multiple enemies at once. I doubt that is the case though, so clearly something is weird with the way they work.

[Nicolaser 2,024]

6 hours ago, Aerobane said:

I just had something quite interesting happen right now and I wonder if its realistic. I'm in the F104S on Preparation for Landing on Hokkaido, 4xAim9B + 2xAim7E. I kill a phantom early with my first sparrow and manage to escape by outrunning everyone and their missiles on the deck. I turn around and start heading back towards the remaining furball although my team is already pretty much gone. As I'm coming in and still about 12km out one of their mig 21s goes vertical and loops over, becoming a good sparrow target. I lock him up and fire at about 9km:

 

Hide contents

 

 

 

 

 

Note the Jaguar slightly to the right and well below the Mig-21, player "Baile_De_Favela."

 

The missile tracks well and continues to do so until I can no longer see it. The Mig dives down and I am able to maintain lock consistently the whole time. Just as I'm expecting the missile to be hitting, I get a team kill on the friendly jaguar. This screenshot was taken from the moment of impact:

 

Hide contents

 

 

 

 

 

Looking back through the replay, I see that the mig passed in near and slightly in front of the jaguar when the missile was 4km away from them. At that time the sparrow was tracking the mig perfectly, although if he continued his dive a big longer and it hadn't switched targets I think it may have just lawndarted trying to intercept his current path at a point under the ground:

 

Hide contents

 

 

 

 

 

About a second after the two merge and while they are heading in opposite directions, the sparrow abruptly switches target turning to the right and up to intercept the jaguar, despite radar lock on the Mig:

 

Hide contents

 

 

 

 

 

Note the missile in the bottom center and its smoke trail. The Mig-21 was heading in the exact opposite direction of this new course so you can see exactly when it switched targets from the sudden turn.

 

I was totally surprised when this happened because neither the missile nor its smoke trail were still rendering for me and I was looking at the Mig. Even though I wasn't zoomed in, the Jaguar was only barely visible at the top right of my screen. I had no idea where it was when I hit him until I checked the replay. Here is my player's view at the moment of impact:

 

Hide contents

 

 

 

 

 

 

Obviously what I assume happened is that even though the radar was still locked on the Mig-21, it was also illuminating the Jag as well and as they passed near each other the sparrow picked up returns coming from the Jaguar and went after it instead. So my question to the experts, does this make sense? I think it depends how the target illuminating works and how narrow the sector it illuminates is. I can understand it switching targets easily but continuing to track the Jag while the radar was illuminating the mig a solid 10-20 degrees or so off to the left and below is noteworthy. I've never seen this type of behavior in any of my other F-104S games (which is quite a few, I've been having a lot of fun with it.)

 

Anyone had a similar experience? Were there cases of this happening historically? Also, RIP 15k SL.

I don't know if that will help but maybe it's related

 

sometimes when I'm behind a phantom and the phantom lock an enemy plane in front of us my rwr from my jaguar A is ringing like if the phantom was locking me

[Zetaris 267]

 

4 hours ago, Aerobane said:

I've just realized what happened to me makes no sense at all. If the radar can effectively illuminate the Mig and the Jaguar at such a wide angle simultaneously, why require radar lock to launch? Shouldn't we be able to just turn on the illuminator, light up everything in front of us, and start spamming sparrows at multiple enemies simultaneously? Because if the radar can illuminate multiple targets simultaneously and illuminate targets that are not locked or close to the target being locked, then it should be able to guide sparrows to multiple enemies at once. I doubt that is the case though, so clearly something is weird with the way they work.

 

2 minutes ago, Nicolaser said:

I don't know if that will help but maybe it's related

 

sometimes when I'm behind a phantom and the phantom lock an enemy plane in front of us my rwr from my jaguar A is ringing like if the phantom was locking me

 

It might be the effect sidelobes:

 

 

Perhaps the side lobes of the CW illuminator were also illuminating the friendly Jaguar.

 

As for why we can't just turn on the illuminator, well, there's a "Flood Mode" feature on F-15 and F/A-18 radars in DCS. I don't recall that being a feature on the F-4E's radar, though.