[WAD] 1271.1 Modern AAM Burn Time Far Too Short.

[bsq]

Boost Coast AAM's seem worse in 1271.1 than ever before. That said this might have happpened during earlier tweaks such as 1267/8/70, just I hadnt noticed.

At 38nm down range my 120D is subsonic and is catching nothing. Thats not even half RMax. At 41nm it stalls!
The burn was around 5 to 10 seconds. The speed bleed off remains dramatic.

The save shows the 2nd volley, plus the 3rd missile about to launch so you can see the speed bleed off.

The database entry for 120D say 105 seconds of fuel. Seems to burn from what I can see around less than 10% of that value.

Something is still not right. There is no way it has the RMax quoted in the database, which I presume is from best info available to devs.

Similar seen for 260. It was done inside 50nm once the head on shot reverted to tail chase (btw it was less than 5nm from the target when it ran out of energy, so it had actually run around 50nm). Here is the 120D save

[bsq]

I ran it on for 15 seconds after 120 # 3 starts to slow. It loses around 260 m/s in velocity in that time. That equates to a 2G deceleration for a missile that should be diving on to its target.
That doesn't feel right for a weapon designed to take out agile aircraft themselves capable of 9G turns and straightline acceleration thats in excess of that deceleration shown by the missile (and I'll leave that out there)

[Dimitris]

The "2G deceleration" thing is addressed here: https://www.matrixgames.com/forums/view ... 4#p5029584

On the matter of missile fuel burn times, the stock DB values are no longer used in the new boost-coast model; they are instead dynamically calculated on-the-fly based on the nominal range values. We should probably tweak the DB viewer to display the dynamic values instead of the stock-DB ones to avoids this confusion.

[bsq]

The "2G deceleration" thing is addressed here: https://www.matrixgames.com/forums/view ... 4#p5029584

On the matter of missile fuel burn times, the stock DB values are no longer used in the new boost-coast model; they are instead dynamically calculated on-the-fly based on the nominal range values. We should probably tweak the DB viewer to display the dynamic values instead of the stock-DB ones to avoids this confusion.

So 41nm, non manoeuvering missile range (so RMax) is WAD for AIM-120D, rather than the 86 NM quoted elsewhere?

BTW when the other post talks about Meteor (exotic propulsion), fuel was done inside 15nm, with an observed RMax (stall) at around 50nm.

[thewood1]

I still am not sure on the 41nm limit on a non-maneuvering target for the 120D. Here's a scenario of a single F-22 with radar on head on to an Su-35. I think the F-22 is around 18000m and the Su-35 is at around 11000m. The F-22 fires at about 80nm. The 120D lofts and is at about 1400 knots when within visual detection of the Su-35. The 35 turns, but is easily caught by the 120D. At max range, the likelihood of a hit is about 50% on a maneuvering target, from what I see. I tried it with a Tu-95 and it was no contest. The 120D intercepts almost every time.

So it seems to me that in a perfect setting where the target has no awareness of the incoming missile until visual, the 120D has plenty of energy for end game. And has been pointed out, if the target does heavy maneuvering, the 120D loses energy very fast. I think the key is when the target detects the 120D and how quickly it starts its turns and maneuvers.

When you open the scenario, switch to the US side and turn on God's Eye to see what happens.

[Dimitris]

I tested the provided save in B1271.1.

I changed the AIM-120D's WRA firing range to "Max". I instructed the Su-35 to head towards the F-22 and set its "Automatic Evasion" setting to NO. The Su-35 is at its present height and at Military thrust (520 knots), the F-22 is heading north, climbing and at Military.

Initial launch of 2-missile salvo at ~88 nm: https://i.imgur.com/jB9Yp0l.png

Impact of first missile, at 48.9nm from the F-22 (NOT from the launch point!): https://i.imgur.com/QuuyFG7.png

Same moment in time, second missile is at 1406 knots so it still has some energy (and thus flying range) left in it: https://i.imgur.com/Vxv39sv.png

[Dimitris]

Second test, same tweaks except this time I respect the "60nm" firing range that you specified for the AIM-120D.

Firing at 58.2nm: https://i.imgur.com/ALCmhtF.png

This time the Su-35 is close enough to launch missiles on its own, and it is cranking. This complicates the engagement geometry: https://i.imgur.com/ZDozabv.png

Nevertheless, the first AIM-120D impacts on it, at 31.nm from the F-22's current position (again, NOT from the launch point): https://i.imgur.com/jC73E7D.png
At that point in time the second missile has a 1210 knots speed.

So far, not seeing anything unexpected.

[Dimitris]

Some general observations:

* The nominal missile ranges in the DB refer to _launch_ range, not _travel_ range. This is part of why the practical launch range can differ wildly according to the engagement geometry.

* Also, in the case of lofting missiles (like the AIM-120) the launch range and the estimated distance-to-intercept will also dictate the lofting profile; for example if the range is significantly shorter-than-max the weapon navigator/autopilot will deliberately reduce its lofting arc, or even go completely straight-in, to reduce the risk of the target "sneaking under" the loft trajectory. This, in turn, because of the difference in altitude and thus drag, can change the velocities at different points in time.

* The nominal weapon ranges, and the boost burn times auto-calculated from them, assume certain "standard" conditions: The launch aircraft is at M1.5 and 36000K ft, and the target is head-on incoming at M1.0 and also 36000K ft. Any change in the actual conditions will change (often drastically) the actual launch range.

[thewood1]

Using my baseline as a baseline.

Test setup - F-22 vs various Russian targets at different ranges head on with the target at 11km and the F-22 6km above that. The F-22 opportunity fire enabled and the target is no automatic evasion enabled.

Su-35 as target

100 nm apart - F-22 fires as soon as the Su-35 crosses 85nm. Result is a lot of misses and a few hits, but the 120D maintains high energy (1400 knots) at end game.
60nm apart - F-22 fires immediately and kills the Su-35 almost every time.
20nm apart - Same as 60nm

Tu-16 - Killed almost every time out to 85nm 120D launching distance.

AS-4 - A few misses at 60-80km, but everything killed closer.

I'll run a few tests with auto evasion off.

With auto evasion off, the results are only different in the number of hits. The missile energy levels seem to be good and not much different than the previous test, as you would expect.

[Tcao]

I tested the provided save in B1271.1.

I changed the AIM-120D's WRA firing range to "Max". I instructed the Su-35 to head towards the F-22 and set its "Automatic Evasion" setting to NO. The Su-35 is at its present height and at Military thrust (520 knots), the F-22 is heading north, climbing and at Military.

Initial launch of 2-missile salvo at ~88 nm: https://i.imgur.com/jB9Yp0l.png

Impact of first missile, at 48.9nm from the F-22 (NOT from the launch point!): https://i.imgur.com/QuuyFG7.png

Same moment in time, second missile is at 1406 knots so it still has some energy (and thus flying range) left in it: https://i.imgur.com/Vxv39sv.png

No matter it is a WAD or a bug, the chasing part create some frustration. In a pure chasing scenario, 120D will run out of energy at 23nm

chasing.jpg (599.46 KiB) Viewed 845 times

[Tcao]

file attached

120D released by a 1000kts F-22 at 11nm, the target is a 920kts Su-27.
Missile out of energy at 23nm distance, 75 seconds flight time. But the 120D's speed has already fall below 920kt at 35 seconds.

I also recorded the aim-120d's speed and Altitude at every 5 seconds (excel file has been attached)

record.jpg (80.9 KiB) Viewed 844 times

[LetMePickThat]

file attached

120D released by a 1000kts F-22 at 11nm, the target is a 920kts Su-27.
Missile out of energy at 23nm distance, 75 seconds flight time. But the 120D's speed has already fall below 920kt at 35 seconds.

I also recorded the aim-120d's speed and Altitude at every 5 seconds (excel file has been attached)


record.jpg

I'll take a look at your excel file, but a 23nm/75s flight time for an AAM in a tail chase scenario is pretty darn impressive.
The energy bleed rate could be adjusted, just like the engine burn rate on most dual-pulse missiles, but apart from that I don't see a fundamental issue here.

[Dimitris]

Indeed that sounds legit and perhaps a tad optimistic.

Physics are a real b*tch in tail-chase engagements, and the faster the target the slimmer the margins. In fact if you had the chance to ask the Su-57 design team why they almost didn't bother at all with rear-quarter RCS and IR signature suppression, this would likely be one of their main arguments.

(This is also why the R-27ET / AA-10D missile, a seemingly paradox combination of large kinematic range and a short-range LOBL-only IR seeker, exists.)

[Tcao]

Hi, thank you both for the explaination

With a dozen posts complaint about missiles are out of speed fast , I guess folks here are not ready for new AAM mechanism.

Does the Dev team have any plan to start a topic, either in genearl discussion or war room sub forum, talking about tactics, setting on the WRA, etc? Some kind of communication should help people to understand the new changes?

[thewood1]

Hi, thank you both for the explaination

With a dozen posts complaint about missiles are out of speed fast , I guess folks here are not ready for new AAM mechanism.

Does the Dev team have any plan to start a topic, either in genearl discussion or war room sub forum, talking about tactics, setting on the WRA, etc? Some kind of communication should help people to understand the new changes?

Isn't that what the War Room is for? Can't you just put it there. Its not very active so its not like the conversation is lost in the crowd.

[DmitriyBlade]

Does NEZ in WRA consider
-Bandit goes hot or cold
-Bandit speed 480knots or 920knots ?

[Dimitris]

Does NEZ in WRA consider
-Bandit goes hot or cold
-Bandit speed 480knots or 920knots ?

NEZ assumes that the bandit, immediately upon weapon launch, turns tail and runs away from the incoming weapon at the same speed that it currently has. (This means that a low-speed bandit can potentially outrun the NEZ shot if it significantly accelerates away)

[DmitriyBlade]

(This means that a low-speed bandit can potentially outrun the NEZ shot if it significantly accelerates away)

Could it be possibly to implement ?
BVR engagement logic: "if Bandit cold - Follow missile straight-in,Hot - crank and drag"

if bandit cold you want push it, so WRA
BVR engagement "Follow missile straight-in"
if bandit hot you want "Crank and drag"

[Dimitris]

(This means that a low-speed bandit can potentially outrun the NEZ shot if it significantly accelerates away)

Could it be possibly to implement ?
BVR engagement logic: "if Bandit cold - Follow missile straight-in,Hot - crank and drag"

if bandit cold you want push it, so WRA
BVR engagement "Follow missile straight-in"
if bandit hot you want "Crank and drag"

Please do not pile feature requests on tech support threads.

Please read this, and internalize it: https://www.matrixgames.com/forums/view ... 0&t=255656

4. Always create a new thread for your issue. Don't add your report to an existing thread even if the OP there looks 100% identical to your own. If you wish to report multiple potential issues then please create one thread for each issue, even if these were observed on the same game session.
Piling multiple issues on a single thread makes it much more difficult for the devs to keep track of what is resolved and what is still pending. This means less time & energy for the devs to resolve your issue.