RIM-116A (RAM) almost never hits

[GumidekCZ]

We know that in DCS same as RL, the RIM-116A had dual guidance, -1st phase RF guidance on antiship missile radar, -2nd phase in certain distance before impact, missile switched guidance to IR seeker from Stinger missile.

Quote

Guidance Passive IR (infrared) radiation provides Zour RAM required accuracy and autonomy, but has limited range, especially when intercepting low-flying targets on a collision course. Furthermore, the IR seeker has a narrow field of view. To compensate for this lack of guidance Zour in the initial section is provided by a passive radar seeker. This is due to the fact that the terminal phase of attack surface ship most anti-ship missiles (ASM) work onboard altimeter active or active homing, and missiles are radio-emitting target.

Guidance using radar channel is carried according to the radio interferometer, two forward-looking antennas which are located in the nose of the rocket. These antennas receive signals from attacking RCC. In the rear are Zour rearview antenna for communication with the ship's radar detection and initial transmission of target data. Undermining fragmentation warhead provide optical proximity fuze.

Источник: http://tonnel-ufo.ru/eanglish/weapon...m-rim-116a.php

 

I watched many ACMI files when US ship used this defence against many antiship missiles, but they never hit something.

Possible reasons:

1) May be because off IR seeker have to big FOV and in will switch from original target to other missile fired from ship showing to RIM-116 seeker its hot tail.

I suspect, that in RL, designers were aware of this problem... and I assume, that they made(keep) seeker FOV narrow or with inverted logic...to not guide on very hot spot but one with much less IR signature (incoming missile).

 

2) Homing on enemy antiship missile radioaltimeter or missile radar not working in DCS really...why? dont know....

 

Found Lua script file for RIM-116A: SA_missiles.lua but didnt found any wrong thing other than:

KillDistance=5 -should be per AIM9L warhead =7,

Sigma = 10,10,10 should be per Stinger seeker =3,3,3

aim_sigma = 20 is very suspicious

(DCS World OpenBeta\CoreMods\tech\TechWeaponPack\Database)

 

Extract attached ZIP for ACMI inside:

Tacview-20201126-221908-DCS-Harpon_test.zip.zip

Tacview-20201126-221908-DCS-Harpon_test.zip.zip

Edited September 30, 2021 by GumidekCZ

[Flappie]

I agree: something is wrong with the RIM-116 missile. Its hit rate is way lower than the AIM-7's, which is 16 years older.

 

RIM-116.trk

[BIGNEWY]

Hi, the team have found an issue and have reported it to the dev team

 

thanks

[Flappie]

Thank you. :thumbup:

[GumidekCZ]

Flappie, I did Re-Run of your test mission, with only single RIM-116 missile hits taget. RIM-116 really need some love and boost, otherwise its just piece of crap launched with some smoke.    RIM-116_Pk_LOW.trk

Also, RIM-116 have less smoke than in game, as you can see in vid. In DCS it has solid rocket motor - full smoke, no transparency. Something like     exhaust = { 0.7, 0.7, 0.7, 0.5 }, (half transparent)

 

Edited June 6, 2021 by GumidekCZ

[Flappie]

I've just replayed my old track and nothng has changed, indeed. I'll ask ED crew about this.

[GumidekCZ]

RIM-116 RAM missile BUG with to high Sigma value still present in OB version.

Fuze setting with distance of KillDistance = 5,

No wonder that missile do nothing. Simga vaule have very big problems when it comes with frontal intercept - which the RIM is trying to do against antiship missiles.

Now: sigma = { 10, 10, 10 },

Should be per Stinger FIM-92 seeker, which the RIM-116 missile have mounted before update it has sigma = { 3, 3, 3 }, now in script abs_err_val = 4, (same as Igla)

Than the chances would be much better.

And again: aim_sigma = 20,  - that is bad, really bad.

I compared Lua file, and found that NOTHING was changed since reported.

RIM-116_HIGH_SIGMA_VALUE_BUG.trk

PLS @Flappie or @BIGNEWY, can you do something about that? Thanks very much in advance.

[GumidekCZ]

Hmmm, today I tried to edit the script to see, if the sigma is the source of the problem.

What I have found is that there is another wrong thing hidden somewhere id DCS that makes the RIM-116 to miss almost all the time, when it try to intercept antiship missile at level or only shallow climb. In steeper climb, the missile have almost 100% accuracy as can bee seen from this track. I have put Tu-22 in longer distance, so antiship missiles not fly low near the sea surface. And it works.

RIM-116_Good.trk

 

Another problem of this missile in DCS is the speed:     The max speed noted in DCS and from many sources elsewhere is M2.5 .... but from track ... you can see that only M2.25 is achieved.

Missile is around only M1.0 at half of its max range of 10km, because of this: cx_coeff    = {1,2.7,0.8,1.36,1.75},   

--this is what can be found on simillar type of well scripted DCS missile:         cx_coeff    = {1,1.5,0.68,0.7,1.75}

--also v_mid needs to be increased from 350 to v_mid = 370.0,

After engine burnout, the missile now slow down almost with same deceleration as was accelerating.

Also I want to add here that if the missile have max range of 10km, than the missile can be launched when antiship missile is not just exact 10km away, but even before it crosses this line.

Now in DCS (to much drag):   My result with suggested vaules:

Edited March 14, 2023 by GumidekCZ