[WAD] AIM-120C (and other AA missiles) Speed falloff

[thewood1]

I'd really like to see a save of the aircraft outrunning a 120 with a 15nm launch. I can't reproduce that. So can you layout the exact parameters for the engagement? Even at a 50% WRA, I rarely see even a fighter outrun a 120.

[Tcao]

Here is the test I did yesterday. The original test's target is to look for the best WRA range in fighter vs fighter scenario. Then I noticed that AIM-120-C-7's speed fall off much faster than R-77.
AIM-120-C-7 petered out at 25nm, while R-77 petered out at 40nm (go to the last save file "ARH 25nm aim-120 vs r-77 124018 r77 petered out", switch to side "godview", I have put reference point for where the missile been released and where the missile disappeared.

I have a similar observation with Gainful. AIM-120-C-7's boost depleted after 10s. R-77's rocket fuel lasted 30s.

The duel happens at 25k ft, 25nm. I will do some more test, change the altitude to 36kft later today and report the finding tomorrow

[Gainful]

Here is the test I did yesterday. The original test's target is to look for the best WRA range in fighter vs fighter scenario. Then I noticed that AIM-120-C-7's speed fall off much faster than R-77.
AIM-120-C-7 petered out at 25nm, while R-77 petered out at 40nm (go to the last save file "ARH 25nm aim-120 vs r-77 124018 r77 petered out", switch to side "godview", I have put reference point for where the missile been released and where the missile disappeared.

I have a similar observation with Gainful. AIM-120-C-7's boost depleted after 10s. R-77's rocket fuel lasted 30s.

The duel happens at 25k ft, 25nm. I will do some more test, change the altitude to 36kft later today and report the finding tomorrow

The tests I did were at 36k ft with 60nm seperation. Its not just the aim-120-c, there are other missiles that have similar issues, and I haven't even tested them all. Who knows how many more are like this.

I'd really like to see a save of the aircraft outrunning a 120 with a 15nm launch. I can't reproduce that. So can you layout the exact parameters for the engagement? Even at a 50% WRA, I rarely see even a fighter outrun a 120.

It first happened to me in this scenario. Its a large scenario but ignore everything else and focus on the "Black Sea CAP E" and "Black Sea CAP W" missions. F-35s and F-22s armed with aim-120-c are assigned to them and will engage fighters over the Black Sea. They've been set to fire missiles at 15nm. Play out the scenario and watch the engagements. The results are a bit random so you might not see it first time around, so just reload and try again.

[thewood1]

Ran two versions of the test. Ran it 8 times. In one test, the I focused my view on the Black Sea CAP E F-35s that went after the SU-35 in the lower southwest. I did monitor the F-35s that went after the Su-35 gaggle in the north of the prosecution zone as well. I saw no issues with any of those intercepts, but the number of close proximity aircraft made it hard to isolate and see exactly who hit what.

But the intercept in the southwest did what I think it should have done. There was a some randomness in the facing of the SU-35. One of the eight times the SU-35 happened to be facing more to the southwest when the missile fired and immediately burned away and outran the 120. But every other intercept in the other seven playthroughs did approximately what is show below. See below that the SU-35 had no time to turn and was killed by the first 120 at about 14 nm.

Screenshot 2022-06-27 152849.jpg (126.89 KiB) Viewed 660 times

Interestingly, this was with Crimea River using db941. I Rebuilt it with 494 and the 120s seemed to have a slightly longer powered envelope. Even in 491, it appears to my eyes that there is a very large dependency on altitude of the enemy unit. The early 120s get a lot of their late run energy from lofting. I don't think the 120s at 15nm have the time to loft very high. Playing around with the 120s beyond this test, I found that the earlier 120s do better between 50 and 75% launch range. They seem to have more time to loft and bring energy to the late flight.

[thewood1]

Interesing discussion from almost 10 years ago.

https://www.key.aero/forum/modern-milit ... -questions

And an assessment of the 120C-5. The rocket motor is about the same as the C-7. Note the references to mmotor burnout between 7-8 seconds. And also note the requirement to loft.

http://www.zaretto.com/sites/zaretto.co ... t-rev2.pdf

[Tcao]

I could be wrong but I guess we have at least two different issues here

First one is AA-12's outstanding performance compared to other missiles, shoot at 36k ft AA-12a will be out of energy at 56nm away, that is more than 10nm compare to 45nm range in the DB description. And R-77 is taking a norm flight profile while other missiles lofting

Second, looks like in current beta version, missile lofting has some issue.

6.28.jpg (442.13 KiB) Viewed 617 times

The AIM-120C-5 on the left side takes a loft flight out of energy at 30nm, the right AIM-120C-5 takes a norm flight out of energy at 48nm (AIM-120 will be lofted by default. To make it takes a norm flight, the trick is to delete the targeted A/C as soon as the AIM120 released, after the aim120 lost the target, it will keep at 36k ft)

[Gainful]

Ran two versions of the test. Ran it 8 times. In one test, the I focused my view on the Black Sea CAP E F-35s that went after the SU-35 in the lower southwest. I did monitor the F-35s that went after the Su-35 gaggle in the north of the prosecution zone as well. I saw no issues with any of those intercepts, but the number of close proximity aircraft made it hard to isolate and see exactly who hit what.

But the intercept in the southwest did what I think it should have done. There was a some randomness in the facing of the SU-35. One of the eight times the SU-35 happened to be facing more to the southwest when the missile fired and immediately burned away and outran the 120. But every other intercept in the other seven playthroughs did approximately what is show below. See below that the SU-35 had no time to turn and was killed by the first 120 at about 14 nm.

Screenshot 2022-06-27 152849.jpg

Interestingly, this was with Crimea River using db941. I Rebuilt it with 494 and the 120s seemed to have a slightly longer powered envelope. Even in 491, it appears to my eyes that there is a very large dependency on altitude of the enemy unit. The early 120s get a lot of their late run energy from lofting. I don't think the 120s at 15nm have the time to loft very high. Playing around with the 120s beyond this test, I found that the earlier 120s do better between 50 and 75% launch range. They seem to have more time to loft and bring energy to the late flight.

So its a database issue? That would explain a few things. I was wondering why in the controlled tests I did, the aim-120-c was performing a bit better but in the scenario they're absolutely atrocious.

I could be wrong but I guess we have at least two different issues here

First one is AA-12's outstanding performance compared to other missiles, shoot at 36k ft AA-12a will be out of energy at 56nm away, that is more than 10nm compare to 45nm range in the DB description. And R-77 is taking a norm flight profile while other missiles lofting

Second, looks like in current beta version, missile lofting has some issue.
6.28.jpg
The AIM-120C-5 on the left side takes a loft flight out of energy at 30nm, the right AIM-120C-5 takes a norm flight out of energy at 48nm (AIM-120 will be lofted by default. To make it takes a norm flight, the trick is to delete the targeted A/C as soon as the AIM120 released, after the aim120 lost the target, it will keep at 36k ft)

Hmm, I didn't notice this, but I'll take a closer look at it. However I did see that missiles tend to linger a lot longer than their max range. Moreso with short range IR missiles. I remember having this engagement where I fired this aa-11 missile that missed its target. It has a max range of 10nm, but it lingered on for something like 20nm at slow speed. My entire flight was shot down because the AI does not fire another missile until the first one is deleted from the game, leaving them completely vulnerable to counterattack. I think the game should automatically delete missiles that cross their max range or fall below a certain speed where they have no hope of catching a fighter.

[Tcao]

I remember having this engagement where I fired this aa-11 missile that missed its target. It has a max range of 10nm, but it lingered on for something like 20nm at slow speed. My entire flight was shot down because the AI does not fire another missile until the first one is deleted from the game, leaving them completely vulnerable to counterattack. I think the game should automatically delete missiles that cross their max range or fall below a certain speed where they have no hope of catching a fighter.

lol, I can feel your frustration because I had the same experience before. First I want to say, the new Beta version is awesome! It makes the CMO feel like a totally new game. Unfortunately, a new feature usually means new bug, with the latest beta implemented tons of new feature we should have no surprise there are some bugs lurking around. A lot of details need our attention, hopefully with our help the Dev team can make CMO better.
I agree with you on this , if the IR missile's speed is lower than 400kt it should be automatically delete or drop the target so the A/C controlled by AI can fire another IR missile

[Tcao]

Sorry, I should post my testing scenario earlier. But last night just right after my post , I realized something I did could mess up the test/conclusions.

Before I issue the manually fire, the target's speed (J-11A / Su-27sk) was set at 480kt
As soon as the AIM-120 missile left F-15, I changed the target's speed to 920kt. That would mess up the AIM-120's aimpoint.

I made several other scenarios, now the target has different speed setting (right after missile fired), 350kt/480kt/520kt/920kt
I haven't got a chance to fully test these scenarios. But with target at 480kt, it looks like the lofting AIM120's energy status is just slightly better than the norm flight. People may argue it should have more speed when it takes a dive.

anyway, here is the testing scenarios

[Tcao]

Here is another one
testing all the ARH missiles max range (when take norm flights)

[thewood1]

I'm not sure on the db thing. All I know is 7 of the 8 I tried at WRA of 15nm hit the SU-35 in db491. In 494, it was 3 of 3. Its not the motor burn, as you pointed to. All the documentation on the pre-C8 120 says between 7-9 seconds. I measured 8 in my CMO tests. Maybe its drag, lofting profile, etc. But its not booster time. One thing to point out is that the R-77's entire claim to fame is its maneuverability and range and all sources state that as soon as the 120 has to do any maneuvering at all, it loses a lot of energy and range. While the theoretical energy of R-77 handles maneuvering targets much better and maintains maneuvering energy much better post-booster than the 120...in theory. There's a reason the 120C-8 (D) went to a completely different motor. Experience in the Balkans and Gulf War 2 showed that the 120C was not perfect at getting to maneuvering fighter aircraft. I think almost all the kills were around 20 miles (not nm).

The real question on the R-77 is did it ever work as advertised. There are sources that state less than 200 for the Russian Air Force were ever procured and are husbanded very carefully by Russian units. The rest of 4000 unit production went with SU-XXs sold export. But both the 120c-5/7/D and R-77 seem to work as theory advertises. The question is paper vs real-world.

What I'm really surprised at is no one has brought any evidence of real-world performance. I spent 30 minutes yesterday and came back with multiple sources on the 120C, 120D, and even some on the R-77 and its theory and issues. Instead of everyone complaining about what they "think" should happen, grab a source that backs up your argument or do the math.

Sources:
Russia's Air-Launched Weapons - Piotr Butowski
Modern Air-Launched Weapons - Martin J. Dougherty
Postwar Air-Launched Weapons, 1945-Present - Thomas Newdick

Online sources:
https://www.afhra.af.mil/Portals/16/doc ... 131404-383
https://theaviationgeekclub.com/f-15-vs ... ied-force/

One thing to note in the sources I found is that all US aircraft accelerated to Mach flight before launching to give more energy to the 120.