Help on Double beaming a missile

[EtherealN]

ACMI: Air Combat Maneuvering Information

 

http://lomac.strasoftware.com/tacview-en.php

 

That tool is absolutely invaluable for analysing your training session.

Basically, download, install, follow the instructions on activating it, then fly a mission and it'll automatically create an ACMI.

[nomdeplume]

I think in this context ACMI == Tacview files - http://lomac.strasoftware.com/tacview-fc-en.php

 

Once set up you can use Tacview to do post-flight analysis of your performance. Very highly recommended by all the serious simmers.

[shackman]

I think in this context ACMI == Tacview files - http://lomac.strasoftware.com/tacview-fc-en.php

 

Once set up you can use Tacview to do post-flight analysis of your performance. Very highly recommended by all the serious simmers.

Yeah I have that installed but haven't used it yet, but will when I get FC 2

[EtherealN]

Why not use it with FC1? Since most people have transitioned to FC2 that'll be much easier than giving people tracks they can't watch. ;)

 

Besides, it's better than tracks at pretty much everything except eyecandy. :P

[shackman]

Why not use it with FC1? Since most people have transitioned to FC2 that'll be much easier than giving people tracks they can't watch. ;)

Because my copy of FC 1 hasn't worked like forever. Sorry:(

 

But I have never used Tacview, is there any chance you could send me a file that would run just so I can see how it works?

Edited July 2, 2010 by shackman

[EtherealN]

If no-one does so before I get home tonight (I'm out enjoying the summer) I'll see about running a flight with some missile action that your tacview should be able to play. Do verify that you have the latest version, though. 0.95 is the latest, I think.

[Nate--IRL--]

Attached is a zip with a few ACMI files.

 

Nate

Tacview-20100603-154207.txt.zip

[asparagin]

Here's also one from me.

Tacview-20100629-220433.txt.rar

[shackman]

Thanks for the files, and i'm up to date with everything except not having Flaming Cliffs 2. I'll get on my birthday of early July.

[thaFunkster]

The defensive split-S is nice and all, but I only really use it when I want to disengage since it basically takes me completely out of the fight. In a multi-ship fight it is basically a big "[expletive]-you" to a wingman or wing lead, since the enemy is now able to completely discount me: I have become irrelevant as a threat and they can gang up on my mate(s). Not a very nice thing to do.

 

I much prefer to notch and then return to the offensive. Even if I don't get an actual shot opportunity again I am at least keeping the enemy on their toes and ensure that I will have an easier time to offer support to a wingman/winglead if they should need it.

 

Shackman, you are on the (roughly) right path. You just need more flight time to get experience with various scenarios to learn to read the situation and make a good call on which defensive method is the most appropriate.

 

Can you explain a little more about the 'notch', I am not familiar with exactly what you mean.

 

Personally, I use the split s whenver I get fired at from near max range, I just keep going in the opposite direction until the missile in no longer tracking me, leave the burners on to put a few extra miles between us then turn back around and get straight back into the fight.

 

Usually the moment I turn back around another missile warning goes off instantly, but then I just do the same thing and the enemy slowly deplets their missiles. Unfotunately, they tend to get closer and closer too, and more than once I have had heaters launched on me after doing this tactic two or three times. But it often works.

[EtherealN]

This is the "look-down clutter notch".

 

Basically: the radar is looking down on you - for example you are at angels 10, enemy emitter (whether active missile or aircraft radar) is at angels 20. Obviously, emitter is higher. So basically place a hand at 10 centimeters above your desk, and then your eyes at 20 centimeters. What do you see behind your hand? Well, the desk. That's the ground.

 

Now place your hand at 20cm, and your eyes and 20cm, and what you see behind will be your wall - that is, sky.

 

So when you are looking down, how do you figure out what is your hand and what is your desk? You recognize features of them - you know what they look like and your eyes receive the photons, and your brain figures it out.

 

Now, for a radar, there is one very big difference between the two scenarios: when "looking down" there's a lot of stuff there that makes the radar waves bounce (called "planet earth" :D ). When level or in "lookup" there is... well... the Andromeda galaxy will give a radar return in about 2 million years, so no worries. ;)

 

So then, no problem in level and look-up.

 

But how do we make our radar figure out what's what in "look-down"? Well, we run some computation on the ground returns to filter them out, largely through doppler return analysis. In practice, this means that an aircraft that has a speed relative to the emitter - and that's important - that is within the filter setting becomes identified as terrain, and therefore the radar ignores it.

 

The specific tolerance that a specific radar uses for this filtering is the "notch gate".

 

Through maneuvering your aircraft such that the hostile emitter is in look-down on you, and then placing your closing speed within the "notch gate", you will disappear. You are now terrain, the radar will lose track, it will not display you as a target, and the missile won't have the faintest about where it's supposed to go.

 

You then turn back towards the guy who launched you and launch on him - but since you were defensive and low you have a "look-up" shot and he cannot hide like that.

 

Your "split-S" tactic basically means one thing: all I have to do to put you out of the fight is launch on you. Sure, I might not get a kill on YOU, but what about your wingman who is left there while you are pointing the other way, completely incapable of supporting him?

 

You left him to die. ;)

[shackman]

What would roughly be the speed for an F-15 or Mig 29 to enter the notch gate?

[Nate--IRL--]

What would roughly be the speed for an F-15 or Mig 29 to enter the notch gate?

 

At a guess +-50km/hr relative to the terrain, but I'm not sure how it's modelled in Lock On

 

Nate

[GGTharos]

+/- 144kph closure relative to ground with the attacker (ie the COMPONENT of the velosity vector TOWARDS the attacking radar) or +/-72kph within 10km.

 

In other words, you want to hit 90 deg (= 0 closure relative to ground, i.e. your closure is equal to ground closure, ie. your doppler shift is equal to ground doppler shift, ie. you have just become part of the ground clutter and have been filtered out as such) perpendicular to the attacker as precisely as possible to notch him. You could slow down, but speed is life and if your opponent has half a brain, you've just killed yourself because you threw away any energy you have had that could be used to kinematically evade missiles in a last ditch defense.

 

What would roughly be the speed for an F-15 or Mig 29 to enter the notch gate?

[thaFunkster]

Thanks for the explanation all.

 

Fortunately, I already understand the concept of doppler radar, so I totally get how this works.

 

The thing is, for this notch tactic to work, you basically have to put yourself at 90degrees or very very close to 90 degrees away from the nose of your launcher.

 

Presumably, the launcher is guiding the missile with its radar, but then what if the missile is not on the line between you and the launch aircraft? Is the missile is Semi Active or Active, it may still be able to pick you out from the ground clutter as it is at a different angle to the hostile aircraft's radar.

 

Sounds like a good tactic to master no doubt, I will start trying to use it, but it seems as though there is a lot of skill needed in order to get it right.

[shackman]

But how exactly can you tell the closure speed of the ground to know what airspeed range to stay at?

[thaFunkster]

Ha! Exactly what I thought - those explanations above will confuse the newcommer more than enlighten him.

 

Allow me to have a try:

 

The enemy's radar looks at one 'radar picture' to the next and compares how much things have moved in that x number of miliseconds. Most of the stuff (if the radar is looking down) will all have moved the same amount and thus the software is programmed to label everything moving at that speed, relative the aircraft, as ground. This all gets filtered out.

 

Now things that are not moving at the same speed as the ground, ie your aircraft all get labelled as contacts, provided they are of a certain size etc.

 

Now if you change you heading so that you are no longer moving away or towards the enemy's front, relative to the ground, then you will effectively only "move" on his radar the same distance as the ground each snapshot that the radar makes. Thus it will reject you as ground and filter you out.

 

So effectively, what they are saying is move perpendicular to the enemy and below him, you want to be moving towards him or away from him at the minimum possible speed. Moving across the front of him left to right, or right to left is ok, but you do not want to be facing towards him or away from him. This will make you look like a peice of ground on the radar.

 

I hope I have succeeded in making some sense.

Edited July 3, 2010 by thaFunkster

[shackman]

Ha! Exactly what I thought - those explanations above will confuse the newcommer more than enlighten him.

Thanks Funkster, I understand how to move so that your speed matches the grounds speed, so you both become 1 in a radar picture.

 

But is there a way to tell how fast or slow to go?

[winz]

Just to be picky :P

The enemy's radar looks at one 'radar picture' to the next and compares how much things have moved in that x number of miliseconds.

It doesn't compare two pictures, it uses dopler effect on radar waves.

 

But is there a way to tell how fast or slow to go?

as GGTharos stated +/- 144kph closure relative to ground with the attacker. How fast you can go is dependand on the angle between you and the attacker

[thaFunkster]

Ok, say you have a gird, X and Y. Enemy aircraft is at the bottom looking up at you, so closure towards him would be on the Y axis.

 

Now if you are going across infront of him, maybe not perfectly at 90 degrees, then you will still have a small Y component to your speed, it wont all be along the X axis.

 

Say, maybe 1/7 of your speed is on the Y axis.

 

The slower you go overall, the slower your Y component will be, thus the more chance you have of fitting in the 'notch window' or whatever it was called above. 144km/h if I remember correctly.

 

So the slower you go, the more chance you have of a notch, but as mentioned above, you dont want to slow down, cause you may need that airspeed to make a last ditch maneavre if the missile re-aquires you, or you will need that airspeed in order to turn and re-engage.

 

So if your going really fast, maybe slow down a bit, but dont overdo it.

 

---

 

EDIT: winz - I know it doesnt use pictures, but it is a very helpful analogy for how a radar operates if I am not mistaken.

[104th_Crunch]

Thanks Funkster, I understand how to move so that your speed matches the grounds speed, so you both become 1 in a radar picture.

 

But is there a way to tell how fast or slow to go?

 

Don't worry about your speed. You will notch the enemy radar if you are fast or slow. Worry about staying 90 degrees to the radar. Even less than 90 degrees at further distances will make the enemy break lock. Watch your RWR for the spike and put it on you 3 or 9 o'clock.

 

Saying that about speed, fly at just over corner speed when your in hot territory. (~350 knots for F-15) when you can. Too fast and you'll turn to wide, too slow and you'll lose energy too fast.

[shackman]

Ok, say you have a gird, X and Y. Enemy aircraft is at the bottom looking up at you, so closure towards him would be on the Y axis.

 

Now if you are going across infront of him, maybe not perfectly at 90 degrees, then you will still have a small Y component to your speed, it wont all be along the X axis.

 

Say, maybe 1/7 of your speed is on the Y axis.

 

The slower you go overall, the slower your Y component will be, thus the more chance you have of fitting in the 'notch window' or whatever it was called above. 144km/h if I remember correctly.

 

So the slower you go, the more chance you have of a notch, but as mentioned above, you dont want to slow down, cause you may need that airspeed to make a last ditch maneavre if the missile re-aquires you, or you will need that airspeed in order to turn and re-engage.

 

So if your going really fast, maybe slow down a bit, but dont overdo it.

 

---

 

EDIT: winz - I know it doesnt use pictures, but it is a very helpful analogy for how a radar operates if I am not mistaken.

 

Oh I misunderstood GGTharos there, you mean don't add 144km/h to your airspeed but that is your airspeed. Oh ok sorry.:doh: I just tried going 144km/h, but crashed. What would that airspeed be in imperial units, or is that imperial?

 

But as GGTharos said at that speed you will have hardly any energy to pull a turn to start the engagement.

Is this mainly a defensive maneuver since you aren't attacking him, or when should you stop and turn back into him so that you can lock him up and attack?

Edited July 3, 2010 by shackman

[winz]

No, 144km/h is diffrence between your closure speed and the enemy airspeed => How fast are you closing to the enemy - his airspeed. (because you want close to him as fast, as the ground, not faster, not slower)

If you have the enemy on 3 o 9'clock position, then this speed is close to 0, even if you are flying mach 2.

[shackman]

No, 144km/h is diffrence between your closure speed and the enemy airspeed => How fast are you closing to the enemy - his airspeed. (because you want close to him as fast, as the ground, not faster, not slower)

If you have the enemy on 3 o 9'clock position, then this speed is close to 0, even if you are flying mach 2.

Ok I didn't hear it was the difference sorry 'bout that.:doh:

 

When you say when you have him on a 3 or 9 position and the speed is 0, thats because you are going your airspeed and subtracting his and keeping the closure around 144km/h.

 

Is there an indicator of the closure speed in the cockpit:huh:

[asparagin]

Is there an indicator of the closure speed in the cockpit:huh:

 

Yes but only if you have radar lock. Check radar display. (depends on each aircraft where it's shown. look in the manual)