A couple quesitons regarding missiles...

[Palamedes]

I am creating some static SAM systems.

Right now I have the MIM-23 HAWK for the west and the SA-3 Goa for the east in the works.

I have the hawk model'ed and working just about how I want it to with regards to the missile, but I'm running into an issue.

I am trying to come up with the correct values for the following parameters;
thrust
thrustTime
maxspeed
maneuvrability

The Hawk is a super sonic missile for example.  It travels at roughly 2.4mach and is pretty maneuvrable all things considered.. but for whatever reason, I can't get the darn thing to hit the SU-25 I have flying back and forth over my launcher.

It seems when the SU-25 is flying away from the missile system, the missile cant catch it!!

I have upped the missile speed to like 5000 just to be silly to see if it can.. and it can't.. (or maybe its passing it.. dunno..)

What should these numbers look like roughly?  

Also, I have tried ever maneuvrability setting from 1 to 200 and it seems like about 120 is right.. But after a while it stops tracking the target.. What causes that?  

How is thrustTime calculated?  if there is no more thrust does the missile stop tracking its target?

Finally, is there a way to do proximity fuses?  Most SAM style missiles of a proximity fuse that will blow the missile when its close instead of relying on an impact..  

So, in short;

thrustTime: is this in miliseconds or what?
thrust/maxspeed: what is a reasonable number here considering the missile is supersonic.. I dont want to screw up game play though.
maneuvrability: what exactly does this number mean?  And is 120 a good amount? too much/too little?
indirectHitRange: can this be used to determine proximity fuse?


Thanks gang.. I look forward to suggestions here.

[Palamedes]

Are my questions too difficult to answer?

[Rubble_Maker]

Hi

here's some example settings you could try. Maneuverability=200 is insane, if you ask me! Try something in the range of 20 to 50, but not more. It might be that the missile goes totally crazy otherwise. Also your prob could have to do with "maxControlRange". If you derive from the standard OFP missile class, you might have a very small control range.

---

minRange=300;minRangeProbab=1;
midRange=1000;midRangeProbab=1;
maxRange=5000;maxRangeProbab=0.9999;

maxSpeed=700
irLock=true;
laserLock=true;
manualControl=false;
maxControlRange=100000;
maneuvrability=12.4;
initTime=0.16;   
thrustTime=8.0;
thrust=1350.0;
airLock=true;

[Rubble_Maker]

btw I can't wait for the SA-3

[Palamedes]

I used quite a few of your settings.. but still some tweeking is needed.

For whatever reason, my missiles still can't catch a SU-25 that are flying directly away from the launcher... It's odd..  But I think I am a lot closer..

[Hudson]

It sounds to me like you made the p3d models for the missiles and forgot to set mass to them. Is this a possibility?

[Palamedes]

I set their mass correctly according to the missiles actual spec's..  *shrug*

I'm getting closer.. the missile is much better now and can take out most fast moving air vehicles coming towards it.. If they are moving parallel (across) infront of it, the missile will usually miss.. (makes sense)..  

but still having a hard time hitting a plane that is moving away at high speed...


Still I'm not unhappy with the results..

[Palamedes]

Okay I have another questions..

Given that the missile object is called "HawkMissile"

and the following is done upon the missile being fired (along with a bunch of other stuff)

_hawk = _this select 0
_missile = nearestObject [_hawk, "HawkMissile"]

How do I get the target of _missile ?

The missile is (typically) locked when fired, so I assume there must be some way to pull up that information.

My goal here is to get an idea of how far the missile has to go to target and make a proximity fuse.  

I know how to detonate the missile, but just not how to get the target information..

Thoughts?

[bigcheese]

if you really want to get the best static missile's defence you need to put a heat-seeking or proxcimity device on it
you also need to have a jamming device on them to really get up their noses!
wether you want to think about this or not i do know what i'm talking about
i'm from the R.A.F 5th spec. wing i fly a fa\18c,
i'm a liuetentant and a specialist in avonics and weapons.
so reply if you ever want any ideas or specifcations i also
have a history with hand-weapons.
 

[Palamedes]

The MIM-23 Hawk does not have heat-seeking or radar jamming capability.  I am attempting to accurately recreate the various missile systems.

To be honest, I'm not sure if the hawk has a proximity fuse either.. but as it is anti-aircraft.. it should.  I could be wrong on that point.  

Both systems require a radar system to be up and running before they become functional.  I will add that as I figure it out.  I'm not sure how to make one unit require another yet.  This is my first addon so I am still unsure how to do some things.  Right now, the Hawk launcher is stand alone.

As will the SA-3 as soon as I finish it.

Can anyone answer my question from above?  Thanks.

[BUNTRO]

there is a script out there by SEFE that makes a nice seeker warhead....i'll attach it if I can...check it out and let me know, for I may have plans with this.  Also, Pal, let me know if you'd be interested in working on some projects together.  I can show you some of my work later.

BUNTRO  :beat:

[Palamedes]

I know we are talking via YIM but I thought I would answer here too to keep others posted..

The script you provided is very interesting.. and good.. And it does give me some ideas.. but it still doesn't answer the one key important thing... How do I get the locked target?

In the script/mission you provided, it's all done in the mission file.. There are only 3 possible targets and they are all assigned IDs in the mission file.

I am hoping to make this happen so that the addon can be dropped into ANY game with out having to do some special mission editing..

[WhisperOFP]

Hi,
I'm also currently coding a SAM system, with great difficulties too.
High speed missiles have hard time hitting targets, unless you give them even higher speed so that they can point at target, shoot and be directly on target, in which case they have a chance to hit.
In the range you are talking about (Mach 2-3), missiles misse very often.
At lower speed, everything is fine, provided you give them correct parameters :

AFAIK, maxSpeed has no effect on the missile behaviour, it is just a reminder in the config.cpp.
Flight profile will be determined by :
thrust
thrustTime
initSpeed (I'm having issues with initSpeed on missiles)
sideAirFriction

The BIS commented config give a formula to calculate the correct thrust value when you know the maxSpeed and thrustTime :
thrust=maxSpeed*0.7*thrustTime
I couldn't get any correct result with this formula, which seems very strange to me, bc thrust is proportionnal to thrustTime, the more time, the more thrust you give, the more the missile accelerate, and result are wrong.
I got better results with this formula :
thrust=maxSpeed*1.125/thrustTime
You'll have to take initSpeed in consideration for a correct use, which would theorically give :
thrust=(maxSpeed - initSpeed)*1.125/thrustTime
I couldn't have initSpeed set correctly for missiles, so I could not confirm that.

With that, the missile accelerate up to maxSpeed, then engine stop, and it decelerate at a rate depending on sideAirFriction (sideAirFriction of around 0.01 seems correct for me).

The second issue is the flight path calculation, which makes the missile miss often.
The 2 parameters I found had big impact on it are
maneuvrability
simulationStep
Missiles at around Mach 1/Mach 2 require maneuvrability to be raised up to 30-50, so that they can turn sharply enough to catch the target in case the target changes its trajectory at the end of the missile flight path. But, from what I've understood, simulationStep describe the time between 2 path calculation by the game, so if you give the missile big maneuvrability while keeping normal simulationStep, there is not enough calculation, and it "overcalculate" lead angle. The missile then makes big turn (a bit like "turn left!"..."oops, too much left, turn right!"..."oops, too much right, turn left!") and completely miss the target. So you need to lower simulationStep so that calculation are made often enough. For a maneuvrability of 25, I found a simulationStep of 0.001 to be correct, the missile will begin with big turns, but then will go straight at target. This creates a minimal range, at which you can't hit target anymore. Real missiles have minimal range of engagement too, so that's not a big deal.

But, and you have encountered the problem, when raising the speed, raising maneuvrability and lowering simulationStep doesn't work anymore, if you raise maneuvrability enough for the missile to catch target, the missile goes completely wrong when fired.
So you need to keep maneuvrability to around 40, and the missile will always near miss.
So you need some proximity fuze.
AFAIK, there is no way of retrieving the target of a locked ammunition. I tried to use "nearestObject" all along the missile flight path to catch air units along the trajectory, but "nearestObject" requires exact class name, no meta-class (like "Air" or "Helicopter") works. Perhaps the class "All" works.
I don't see any correct way to do it IN AN ADDON. It is very feasible in a mission, but addons has no knowing of installed units in missions.
Perhaps the missile has a "knowsAbout" list (that would be weird :wow: ), or... well, I don't know.
DKM team is currently working on a proximity fuze to update their 2S6, and I bet they have found the solution

BTW, how do you detonate a flying missile?

Whis'

[Josef]

I have a solllution, a simple one...

I am not sure if it works...

Give the missile a huge "shield" LOD, a big round plate at the front, not textured or anything...

That way if it has a 10 M Radius plate, it will detonate when the 20M Diameter plate hits anything...Also, place the plate 10 M in front of the missile, so it wont be spawned hitting the ground...This way, when the missile is 10 behind, and nearly hits the target it will burst, gove it 15 Indirectdammage range to kill the plane...

Oh, and It will be a "HIT", im not sure it makes any difference, but It will count as a hit anyway...

[Rockape]

if you really want to get the best static missile's defence you need to put a heat-seeking or proxcimity device on it
you also need to have a jamming device on them to really get up their noses!
wether you want to think about this or not i do know what i'm talking about
i'm from the R.A.F 5th spec. wing i fly a fa\18c,
i'm a liuetentant and a specialist in avonics and weapons.
so reply if you ever want any ideas or specifcations i also
have a history with hand-weapons.
 

*Cough*  After doing 9 years with the RAF Regiment and having been deployed around the world in various roles, I've never seen an F/A-18C in RAF colours.  I'm also curious what the "5th Spec Wing" is?   ;D

@Palamedes

The Hawk SAM is IR (Infra Red), IFF (Identify Friend or Foe) or Impact fused.

The Iranians still use the stock missile guidance as far as I know.  I cant remeber reading anythign to say they were mod'ed. But I may be wrong.

The Israelis upgraded thier stocks in the late 80's and added Proximaty fusing on a small number and  then later looked into I-IR (Imaging Infra Red) Seekers before discontinuing the project in favour of the Patriot System.  Which in hindsight I suspect they sorely regret.  ;D