AIM-7 Performance

[mytai01]

Don't your targets have ECM and Chaff? Don't they maneuver to beam the missile?

[j-tk]

I had a sparrow pull up beside the F5, knock on the window, ask directions, and kept on going without detonating. Target refused to show back up on radar after that so had to go to afterburner and close and use sidewinders.

[shagrat]

Try the Aim7m on the F15C. You will see similar results.

Maybe. I rarely flew the F-15C, but then this is the F/A-18C section. Better post a bug report for the F-15C.

 

As the F/A-18C A/A capabilities are pretty much WIP during the early access phase, this isn't exactly what the final performance will be... ED has subject matter experts at hand, and I suspect, they will point out what is or is not wrong with radar and missile performance, before the release.

[shagrat]

I had a sparrow pull up beside the F5, knock on the window, ask directions, and kept on going without detonating. Target refused to show back up on radar after that so had to go to afterburner and close and use sidewinders.

Yep, the radar is heavily work in progress. This is to be expected.

[Jack McCoy]

Maybe. I rarely flew the F-15C, but then this is the F/A-18C section. Better post a bug report for the F-15C.

I'm reading this thread because I'm observing the same disappointing performance with the AIM-7 Sparrow. BUT, I didn't find a AIM-7 Sparrow sub-forum.

 

"This is the F/A-18C section"... Are you suggesting the post is in the wrong place? The comparison with the F-15C is very pertinent here as it might indicate the issue having nothing to do with EA/WIP AA radar of the Hornet, which seems to be the excuse...

[shagrat]

I'm reading this thread because I'm observing the same disappointing performance with the AIM-7 Sparrow. BUT, I didn't find a AIM-7 Sparrow sub-forum.

 

"This is the F/A-18C section"... Are you suggesting the post is in the wrong place? The comparison with the F-15C is very pertinent here as it might indicate the issue having nothing to do with EA/WIP AA radar of the Hornet, which seems to be the excuse...

The missile performance is likely tweaked when the radar is getting the full modes and features.

Think about it. They implemented the AIM-7 Sparrow into the Early Access, not because it was fully functional and integrated into the radar, but everybody wanted ANY long range missile.

My wild guess, they just took the AIM-7 from FC3 and that is it, until the more detailed simulation of A/A radar is ready and into early access.

So of course the missile does not perform realistic. And of course it won't see any improvements until they are going to finalise the radar and AIM-7 interaction.

 

If the performance on the F-15C is "so bad" I wonder why it has never been updated?

Anyway, to say the performance of the AIM-7 is not realistic as it is like in the F-15C, and lots of people didn't like the performance in the F-15 either, won't do much.

 

Beside that I think the "real" performance may be very different from any books, videos, hearsay or even personal observation, unless the person observed a lot of shots with different parameters or has access to Raytheon's internal performance charts (which are likely classified?).

I found a nice overview of the different AIM-7 variants, that was lead by a very honest commentary, I'll cite: (...)"Data given by several sources show slight variations. Figures given below may therefore be inaccurate! The AIM-7's range depends heavily on firing parameters and aircraft radar, and the numbers given below are only rough estimates for maximum effective range in head-on engagements."(...)

Source: http://www.designation-systems.net/dusrm/m-7.html

 

Simply by looking at the "range-performance" of the AIM-7M vs. RIM-7M (same missile launched from Ship-to-air) it shows how relative a suspected "realistic range" may be.

 

Another interesting comment about the hit rate of the AIM-7M noted 37%(!), that is with a fully functional radar, trained operators/pilots...

 

So from my point of view the current "performance issues" are to be expected and we need to wait until ED updates the radar (what is announced as a priority for the F/A-18C) until we should guesstimate about realistic or unrealistic performance of a missile/radar combination that is heavily WIP and likely nobody can show more than some marketing papers and internet links about "real performance" unless he has a very good lawyer or a country that grants him asylum if need be. ;)

 

I don't mean the performance is perfect at the moment, I would expect a better range and more constant and reliable lock, as well. But I am sure this is exactly what ED is working on currently.

Edited June 21, 2018 by shagrat

[gavagai]

I don't mean the performance is perfect at the moment, I would expect a better range and more constant and reliable lock, as well. But I am sure this is exactly what ED is working on currently.

 

Heh, fly the Mirage lately? It's better than the F-18+Aim-7, but if your target notches below the horizon you will lose lock, every time.

 

The days of boy-scout radar in DCS are coming to an end. I can't wait for the FC3 planes not to lock me up while I'm on the taxiway.

[shagrat]

Heh, fly the Mirage lately? It's better than the F-18+Aim-7, but if your target notches below the horizon you will lose lock, every time.

 

The days of boy-scout radar in DCS are coming to an end. I can't wait for the FC3 planes not to lock me up while I'm on the taxiway.

I think nobody has a problem if he loses lock because the target maneuvers defensive effectively. What is a problem currently, is that you lose lock while simply flying a crank or bank a bit to hard and often can't reacquire a none moving target... But as said this is more related to WIP, so we shall see how good or bad the radar turns out, after finalization and input from the pros.

[tflash]

I think it's part of the fun to loose lock, and the Sparrow is quite good at relatively close ranges I feel! Anyway I'm havi ng a blast dogfighting in the Hornet (& Mirage) !

[GGTharos]

Heh, fly the Mirage lately? It's better than the F-18+Aim-7, but if your target notches below the horizon you will lose lock, every time.

 

... which is a feature of every doppler radar modeled in game, FC or otherwise.

 

The days of boy-scout radar in DCS are coming to an end. I can't wait for the FC3 planes not to lock me up while I'm on the taxiway.

 

What a statement :) Try turning your jammer off. Or taxi slower :D The notch gate on some of these radars can be as low as 48kts in some cases. And FYI, I had no trouble locking onto non-moving aircraft with the F-18's A2A radar either.

[blkspade]

Yep, I've totally been locked up on the ground by a hornet.

[IASGATG]

The missile performance is likely tweaked when the radar is getting the full modes and features.

Think about it. They implemented the AIM-7 Sparrow into the Early Access, not because it was fully functional and integrated into the radar, but everybody wanted ANY long range missile.

 

Sure, they could have put 2 place holder AIM-7 variants to accompany the 7M, with all three missiles having identical code until they decide which direction they want to take things. However your quote of "any long range missile" then doesn't make sense, since they already have the 7M in the game.

 

My wild guess, they just took the AIM-7 from FC3 and that is it, until the more detailed simulation of A/A radar is ready and into early access.

What does the radar have to do with anything? As established there are two problems with the missile. Firstly it's Cd curve is wrong, and secondly the guidance logic overall for all missiles is simple. ED has confirmed they are fixing at least the second at some point (Wags in August 2015). Neither of these things require the F-18 module to fix, so I'm not sure why you mention this.

 

So of course the missile does not perform realistic. And of course it won't see any improvements until they are going to finalise the radar and AIM-7 interaction.

 

See above, although I'm not sure if it's been confirmed whether ED agree that the missile isn't flying fast enough. In all previous posts I have seen, ED is happy with the flight model of the missile, just not how it guides.

 

Beside that I think the "real" performance may be very different from any books, videos, hearsay or even personal observation, unless the person observed a lot of shots with different parameters or has access to Raytheon's internal performance charts (which are likely classified?).

 

We don't need books, videos or hearsay, as we have access to publicly available information on the level flight performance of the 7F. Since the F, M and P all have the same shape and motor, they will all have identical level flight performance. The missiles in game do not match up with these charts.

 

I found a nice overview of the different AIM-7 variants, that was lead by a very honest commentary, I'll cite: (...)"Data given by several sources show slight variations. Figures given below may therefore be inaccurate! The AIM-7's range depends heavily on firing parameters and aircraft radar, and the numbers given below are only rough estimates for maximum effective range in head-on engagements."(...)

Source: http://www.designation-systems.net/dusrm/m-7.html

 

This is literally saying "There is a LARs construct for missiles", which everyone knows. I don't see how this relates. Due to the nature of the website, I would guess it's trying to give the general public a rough explanation of "Hey, the max range is listed at 40nmi, however obviously this can't be done at sea level, or with an old radar."

 

Simply by looking at the "range-performance" of the AIM-7M vs. RIM-7M (same missile launched from Ship-to-air) it shows how relative a suspected "realistic range" may be.

 

Sure, comparing a sea level shot at M0.9 vs a sea level shot at M0 will yield different ranges. However the AIM-7M in game doesn't reach either of them.

 

Another interesting comment about the hit rate of the AIM-7M noted 37%(!), that is with a fully functional radar, trained operators/pilots...

 

Always gets brought up and is never relevant. :(

 

So from my point of view the current "performance issues" are to be expected and we need to wait until ED updates the radar (what is announced as a priority for the F/A-18C) until we should guesstimate about realistic or unrealistic performance of a missile/radar combination that is heavily WIP and likely nobody can show more than some marketing papers and internet links about "real performance" unless he has a very good lawyer or a country that grants him asylum if need be. ;)

 

I don't mean the performance is perfect at the moment, I would expect a better range and more constant and reliable lock, as well. But I am sure this is exactly what ED is working on currently.

 

I agree that ED has said it's WIP and stuff will change, and I really do think they ED just wants what's best. At the end of the day the people who benefit most from a happy community is them.

 

As for information on realistic performance, I'll post what I can share here in one place for reference.

 

 

 

 

 

I have a bunch from the F-4 Tacman manual on the AIM-7E2 which I'll have to dig out as well if interested.

[TAW_Blaze]

Currently you have 1 PRF mode (not MED..) and the radar will lose lock every other second if either your target or you're maneuvering. Not a shocker it'll go ballistic all the time.

[Chizh]

What launch speed for this Aerodynamic Range?

Is it Max Velocity from row above?

[shagrat]

(...)"We don't need books, videos or hearsay, as we have access to publicly available information on the level flight performance of the 7F. Since the F, M and P all have the same shape and motor, they will all have identical level flight performance. The missiles in game do not match up with these charts."(...)

Though the mismatch is right, there are important differences between guidance systems from F to M model, that will impact the effective range.

 

If we get a plain level shot that reaches the public available charts it will be a good starting point to tweak from.

 

I am pretty sure loft options with the AIM-7M model, altitude and aspects, etc. impacts the textbook performance heavily.

 

Always gets brought up and is never relevant. :(

Well, reading a lot of complaints about the AIM-7 missile's hit ratio, it is relevant to put expectancy into perspective, I guess.

 

If we expect a 80% hit rate, while real life performance is more below 40% we may need to except that half our missiles will likely not score a hit... Of course parameters and situation has a large impact, as well.

But like some people do, expecting max range shots against maneuvering targets to score a hit seems a bit overly optimistic.

[backspace340]

What launch speed for this Aerodynamic Range?

Is it Max Velocity from row above?

 

That's from this document: https://drive.google.com/file/d/17jFGpfatEjUbFChZEER_hMshjjuIgq1K/view

 

I can't see the answer to your question, but there are charts on page 5 of that which do state the launch speed and range for a number of different scenarios that might be useful.

[backspace340]

Well, reading a lot of complaints about the AIM-7 missile's hit ratio, it is relevant to put expectancy into perspective, I guess.

 

If we expect a 80% hit rate, while real life performance is more below 40% we may need to except that half our missiles will likely not score a hit... Of course parameters and situation has a large impact, as well.

But like some people do, expecting max range shots against maneuvering targets to score a hit seems a bit overly optimistic.

 

It's tricky though - if you look at missiles fired on PVP servers today you'll probably find a similar hit percentage. People don't always fire missiles to kill - they can be warning shots, shots to send people defensive and shots to see if a cold target will panic and turn around.

 

However, if I fire a missile within kill parameters and it runs out of puff even though the target didn't defend, then that's something different entirely.

[gavagai]

Agree shagrat. Right now the F-18 loses lock with even small control inputs. It will have to improve in that respect so that cranking is possible.

 

It seems like a happy accident that the F-18 cannot equip the Aim-120 for a few weeks (months?). Otherwise the Aim-7 would never have received so much attention.

 

:)

[TAW_Blaze]

Pretty much, not many people used the 7 in the Eagle and now they are all suddenly forced to use it with a disfunctional radar which makes the already not so stellar performance exponentially worse.

 

Whether the kinematic / guidance performance of the missile itself is accurate or not is a different debate.

[IASGATG]

What launch speed for this Aerodynamic Range?

Is it Max Velocity from row above?

 

Hey Chizh buddy. I've been given permission to show this which should clear everything up.

 

 

What's interesting is that the vanilla 7M actually outperforms in the 50kft shot slightly. It arrives at M2.2 I believe? Instead of M2.0 (For the 38nm shot). It's the low altitude shots that the missile falls very short in. Basically the transonic drag is too high and the M4 drag is too low. Ive done my best to bend the curve to fit these variables and after about 55 iterations I got pretty close, still slightly too fast at 50kft. Probably because the drag reduction for the motor being lit isn't represented so I have to make the missile too slippery.

Edited June 22, 2018 by IASGATG

[shagrat]

Sure, they could have put 2 place holder AIM-7 variants to accompany the 7M, with all three missiles having identical code until they decide which direction they want to take things. However your quote of "any long range missile" then doesn't make sense, since they already have the 7M in the game.

I was referring to the fact that ED put the existing "FC3" AIM-7 into the F/A-18C early access release, while not perfectly integrated with the radar, opposed to only have the AIM-9 available on launch.

 

What does the radar have to do with anything? As established there are two problems with the missile. Firstly it's Cd curve is wrong, and secondly the guidance logic overall for all missiles is simple. ED has confirmed they are fixing at least the second at some point (Wags in August 2015). Neither of these things require the F-18 module to fix, so I'm not sure why you mention this.

The complaints about the "Shoot" cue coming far too late and lock being so bad are directly related to the current WIP radar, not the missile itself.

 

As you have mentioned there are two different issues that need to be addressed.

1) flight model and performance of the missile(s). As far as I am aware already on EDs list, I have read about lookin into better guidance and loft modes, etc.

 

2) integration and optimization of the new realistic radar simulation opposed to the more "simplified" FC3 radar.

This should be part of the F/A-18C development and ED said as much.

 

From that results I hope all missiles and radars will get an overhaul and we hopefully get better performance between platforms, especially FC3 titles versus DCS level sim.

Time will tell, I am sure this isn't done in a few weeks...

[shagrat]

It's tricky though - if you look at missiles fired on PVP servers today you'll probably find a similar hit percentage. People don't always fire missiles to kill - they can be warning shots, shots to send people defensive and shots to see if a cold target will panic and turn around.

 

However, if I fire a missile within kill parameters and it runs out of puff even though the target didn't defend, then that's something different entirely.

Yep.

[Krippz]

Hey Chizh buddy. I've been given permission to show this which should clear everything up.

 

 

What's interesting is that the vanilla 7M actually outperforms in the 50kft shot slightly. It arrives at M2.2 I believe? Instead of M2.0 (For the 38nm shot). It's the low altitude shots that the missile falls very short in. Basically the transonic drag is too high and the M4 drag is too low. Ive done my best to bend the curve to fit these variables and after about 55 iterations I got pretty close, still slightly too fast at 50kft. Probably because the drag reduction for the motor being lit isn't represented so I have to make the missile too slippery.

 

This should clear everything up.

[OnlyforDCS]

Time will tell, I am sure this isn't done in a few weeks...

 

Of course not. However for those of us who have been following it closely, the issue with missiles in DCS has been an ongoing one for several years now.

 

It has definitely been longer than a "few weeks".

 

The Hornet's radar issue is completely separate from the problems that the AIM7 in particular, and all missiles in general share in DCS. Im sure that ED will quickly implement and solve the Hornet's radar problems, however that is a discussion which belongs in another thread anyway.

[blkspade]

I was pretty sure the original document posted called for an aerodynamic range of 53nm from 40kFT M2.0. If you fired at 53nm against a head on non-maneuvering target the missile wouldn't even have traveled as far in the first place by the time it reaches the target. Max relative range suggests that's how far it would actually have traveled to intercept in that scenario, meaning there should be energy to spare at that point. However I'd imagine the firing platform would likely need to have closed the gap to be hitting the target with enough energy to effect the sensor range, but the document is rather specific to the F4 in that regard.

Edited June 22, 2018 by blkspade