Is this right? F-15C always explodes, Su33 almost never explodes.

[GGTharos]

You're missing the point - off-bore weapons capability gives you the ability to quickly attack ... off bore targets. It isn't a magical thing, and the seeker is still very vulnerable tot he same things. It will -not- be able to keep up with a close-in merge for example, because the seeker slew is too fast - it's doesn't MATTER that you can 'turn your body' ... it's about how fast you can turn your eyes ... lock is lost more often nowadays not from gimballing out, but due to high LOS rate. It really doesn't matter if it can vector thrust and how wide the gimbals are, if the seeker simply can't slew fast enought o track the target - you have TO TRACK THE TARGET FIRST to order the VC to do its thing.

 

The R-73 is just as vulnerable to this as the 9. I'll stress again, save for the gimbal difference, those seekers can be considered to be the 'same thing' ;)

 

The 9's performance isn't much different than the 73's - what makes up the difference is the vectored thrust and wider gimbals give you the ability to attack off-bore targets at short ranges ;) That's the difference.

 

 

Right now, only modern missiles like the Python 5 and AIM-9X are advertized as capable of whacking a target in the merge - the 73 -cannot- do that, even if you launch within the 45deg gimbal limit. Newer versions of the 73 do better.

 

It's a very good weapon, and it outperforms the sidewinder in many ways, but it isn't magical; it's an expanded kill envelope that it offers, not death ray capability. A maneuvering target can still outmaneuver it about the same as it would with a sidewinder due to a huge, huge number of issues associated with guidance at the very least.

 

Again, to make my point clear: It's a superior weapon, not a magical one. it allows for much greater freedom of engagement, but it doesn't increase overall Pk, just the envelope of high Pk.

 

As for how many G's it can pull ... that's rather superfluous, and not necessary to know - what you want to know is, how many G's can the TARGET be pulling so you can still hit it? That's the important part, and it isn't the same as how many G's the missile can pull.

[Weta43]

I never thought it was magical - just better than an AIM-9. In fact I must have missed the post where someone said it was magical, not just better because of its ability to engage high G manouvering & off bore targets.

 

I have agreed (again - I never actually disagreed) with you that these missiles were are as succeptable to countermeasures as their Western contemporaries. I disagree with your statement that being able to turn quickly is not relevant to the rate at which a target moves across a seekers field of view. See my analogy above - turning quickly reduces LOS rate. Once launched, if the missile turns fast enough, the target won't move across the seeker at all, it will stay in front of the missile nose - if you can point out the error in my reasoning feel free... and as one of the limiting factors for a seeker is the angular rate across the seekers FOV (60 degrees / sec for R-73) anything that reduces that angular rate (like turning to track the target & keep it in front of the missile's nose) increases the chances of maintaining a lock. At the same time it increases the chances of a hit.

 

 

How many G's the missile can turn are directly relevant to the missiles ability to hit the target - the prototype R-73 with no control surfaces could still turn to face the target & keep the target of its nose (thereby reducing the LOS rate & allowing it to maintain lock, but not physically manouver and change its course to intercept. (target G limit for R-73 12G)

 

I don't understand where you're going with this statement though:

 

"it allows for much greater freedom of engagement, but it doesn't increase overall Pk, just the envelope of high Pk."

 

Ignoring the fact that the greater range acually increases the whole engagement envelope, not just the envelope of higher PK, if it increases the size of the envelope of high PK, & allows for greater freedom of engagement, then more of what were marginal shots with the AIM-9 will be kills & a whole lot of shots you could never have contemplated with the AIM-9 can be taken - though only some of them will hit. So in the first case (where an AIM-9 launch is possible) you get more kills per launch - a higher PK, and in the second you get perhaps the same % PK per launch as with the AIM-9, but in situations where the AIM-9 can't launch. Now these may bring your PK per launch back down to that of the AIM-9, but that is "lies, damn lies and statistics", cause the end result is more planes destroyed.

 

;-)

[GGTharos]

I disagree with your statement that being able to turn quickly is not relevant to the rate at which a target moves across a seekers field of view. See my analogy above - turning quickly reduces LOS rate. Once launched, if the missile turns fast enough, the target won't move across the seeker at all, it will stay in front of the missile nose - if you can point out the error in my reasoning feel free...

 

Well, just go through the exercise of your analogy ... you have two problems. First, if the aircraft is exceeding LOS limitations to begin with, you might get a lock indication but it won't work (but we'll leave that one alone, no idea how probably it is) ... second, when you have an aircraft aproaching quickly and increase its LOS rate, you might launch it before the LOS rate become too great, but it becomes too great shortly after launch, and the missile loses lock - turning just doesn't matter.

 

Furthermore, vectored thrust turns are quite rapid - you'll be slewing quickly wether it's forwards or backwards, with the aim of establishing collision course ... another thing to consider: The seeker is 'fixed' in the target, and the body pivots about the seeker's gimbal ... I think you'll find that even with TV you'll out-rate quite quickly right in the middle of the turn, given the right circumstances. There are some shots you just shouldn't take - not with the -old- missiles ... newer missiles(eg. AIM-9X) have a pretty incredible slew-rate. Note I'm not even getting into CM's right now, other than LOS rate.

 

and as one of the limiting factors for a seeker is the angular rate across the seekers FOV (60 degrees / sec for R-73) anything that reduces that angular rate (like turning to track the target & keep it in front of the missile's nose) increases the chances of maintaining a lock. At the same time it increases the chances of a hit.

 

But you're not reducing -anything-. You -might- reduce it, but the TV is designed to point the missile on the right path ASAP, not to preserve your lock. The turn alone may out-rate the seeker if the distance is short enough. This isn't an issue of the missile attacking a target within its envelope - we already agreed that a TV/wide gimbal missile has an expanded engagement zone. Point is, it has its limitation and there's nothing you can do about it - the sidewinder could track a similar target too, but without TV it can't turn to it fast enough. However this is NOT a close merging target. It's a moderate LOS-rate target; only new missiles claim any capability against very high LOS rate targets. That's really all there is to that.

 

How many G's the missile can turn are directly relevant to the missiles ability to hit the target - the prototype R-73 with no control surfaces could still turn to face the target & keep the target of its nose (thereby reducing the LOS rate & allowing it to maintain lock, but not physically manouver and change its course to intercept. (target G limit for R-73 12G)

 

No, that's not correct - how many g's it can turn depends on the max speed. That's why this figure is misleading. You can pull 32 g's at mach 3, or 24g's at mach 2, but you'll actually have the same angular displacement.

 

I don't understand where you're going with this statement though:

 

"it allows for much greater freedom of engagement, but it doesn't increase overall Pk, just the envelope of high Pk."

 

Ignoring the fact that the greater range acually increases the whole engagement envelope, not just the envelope of higher PK, if it increases the size of the envelope of high PK, & allows for greater freedom of engagement, then more of what were marginal shots with the AIM-9 will be kills & a whole lot of shots you could never have contemplated with the AIM-9 can be taken - though only some of them will hit. So in the first case (where an AIM-9 launch is possible) you get more kills per launch - a higher PK, and in the second you get perhaps the same % PK per launch as with the AIM-9, but in situations where the AIM-9 can't launch. Now these may bring your PK per launch back down to that of the AIM-9, but that is "lies, damn lies and statistics", cause the end result is more planes destroyed.

 

;-)

 

No, actually, that reasoning is incorrect. You'll have about the same Pk in the high-Pk zones of both missiles. You won't see more R-73's hitting than AIM-9's in the 9's high-Pk zone ;)

What you will see is 73's hitting well outside the 9's Pk zone. The 73's OB Pk WILL be lower than the 'mainzone' Pk because the conditions of the shot are more extreme. However in the high Pk Zone of the 9 there's effectively no difference between the two missiles, because their guidance unit is effectively quite similar. You can probably work that one out on paper ;)

 

As for statistics, I've heard of a whole lot more AIM-9 kills than R-73 kills, and specifically, the AIM-9M so far has had significantly higher Pk than the R-73. Now that may be due to maintenance, training, etcetc, but you just don't know ;)

 

Frankly, if you launch a 73 at a crossing target, you should get the exact same behavior you get out of a sidewinder: Lost lock. And it's all due to causality (Seeker must track target FIRST, etcetc)

[Force_Feedback]

As for statistics, I've heard of a whole lot more AIM-9 kills than R-73 kills, and specifically, the AIM-9M so far has had significantly higher Pk than the R-73. Now that may be due to maintenance, training, etcetc, but you just don't know ;)

 

Well, how long does the AIM-9 exist? And the R-73?

 

Frankly, if you launch a 73 at a crossing target, you should get the exact same behavior you get out of a sidewinder: Lost lock. And it's all due to causality (Seeker must track target FIRST, etcetc)

 

But you can't launch an R-73 without a "lock", at least, not outside the seekers FOV. The angles of a lock are 60* for the RDM-2 mod (what's now in service in the RuAF and CIS AF-ces), but the angular offset of the seeker itself is 75*, so if a target is 75 degrees off bore, you can't lock it with your plane's sytems, as they won't track it beyond 60*, but the missile's seeker can "see" up to 75*, so if you're lucky enough, and the target is within the seeker's FOV you might get your kill. But, in a "normal" situation (where the pilot doesn't fire free missiles, and there isn't a chance you might end up in a burning heap of aliminium and titanium) the missile can be fired at or less than 60*, but the seeker headcan go all the way to 75* when it's tracking the target (while its flying on its own).

 

 

 

BTW, just read that China will buy 1500 RVV-AEs for their su-30s and Vympel started working on a 5th gen close range missile (not an update of the r-73 design, something new), and they will be updating the RVV-AE, R-37 and R-73/74 inventory. Meanwhile Ukraine designed an active seeker head for the R-27 (lol, now lets hope they will call it the R-27AE :P), which is logical considering they have lots of those missiles in storage. They're also made laser guided S-8 missiles, that are carried in almost the same rack as their unguided counterparts, made for Singapore.

[Vati]

GGTharos, you really are a cherry. Arguing for nothing just to have the last word on the topic :)

Thanks for enlighting us that if target goes out of parameters the missile will miss. We never thought about that. ;)

[GGTharos]

GGTharos, you really are a cherry. Arguing for nothing just to have the last word on the topic :)

Thanks for enlighting us that if target goes out of parameters the missile will miss. We never thought about that. ;)

 

 

SHHHHHHH! ;)

[Shotsx74]

Well some ppl forget that missiles cant go forever and they wont always have the fuel to get there either... so i think he was right in say that

[Shotsx74]

But on topic, i have alwasy been able to eject, i think maybe 4-5 times i havent been able to and thats geting gunned becuase my brain splatters agsint the panel of my cock pit so...

[Weta43]

Fun as it's been - my last post on the matter & pictures paint a thousand words. So regarding turn in rate (G’s in turn) & seekers losing lock because the target is moving too quickly across the seeker’s field of view:

 

 

Two missiles starting from the same position relative to their targets & already locked. Both have reached the same constant speed and maintain that speed throughout.

· The black line and triangles show the path and position of the target after each time interval, as do the successive missiles and their attached arrows.

· The grey “V” in the box above the missile in each drawing indicates the maximum change in direction each missile is allowed to make per unit of time. The grey “V”s are copied & aligned with the front of the missile at the start of each time period to show that the limits are not exceeded. (Because they both have the same velocity but the red missile can change direction more quickly the radius of the circle on the left is smaller, and because a = v^2 / r, the missile on the left has a higher acceleration towards the centre of its circular path than the missile on the right – it’s pulling more “G”s. (which is why it can turn faster :-))

· The light purple lines joining the front of the missile to it’s target represent the angle the seeker would have to be pointed at to track the target at each point in time.

 

Things to note:

 

1. The red missile hits its target; the blue one misses its target. This is because it is capable of a higher “G” turns - the radius of the turn is smaller, while the speeds are the same (a = v^2 / r), and because:

2. After the red missile leaves the green circle, it keeps the target directly in front of it’s nose, meaning that is not moving across the seekers field of vision at all. The only time the target is moving across the red missile’s seeker’s field of view is while it is in the green circle & during this time it is moving into the field of view.

3. The blue missile never gets the target in front of its nose & not only does the target move across and eventually out of the seeker’s field of view, the RATE at which the target moves increases with each passing time interval till somewhere in the red oval the rate of movement across the field of view would exceed the seeker’s angular change limits and the lock would be lost.

 

 

In what seems to me to be a classic case of trying to have your cake & eat it too, you say that turning does not affect the rate of movement across the seeker’s field of view, but also suggest “But you're not reducing -anything-. You -might- reduce it, but the TV is designed to point the missile on the right path ASAP, not to preserve your lock. The turn alone may out-rate the seeker if the distance is short enough” i.e. that the affect of a very rapid turn might be to lose track because of excessive movement of the target towards the centre of the seeker’s FOV.

If the designers of the guidance system (which controls the TV system) didn’t think of this, then yes that may be a problem, but would be a relatively simple thing to counteract by limiting the rate at which the guidance system tries to centre the target.

 

You also wrote: “You'll have about the same Pk in the high-Pk zones of both missiles. You won't see more R-73's hitting than AIM-9's in the 9's high-Pk zone

What you will see is 73's hitting well outside the 9's Pk zone. The 73's OB Pk WILL be lower than the 'mainzone' Pk because the conditions of the shot are more extreme. However in the high Pk Zone of the 9 there's effectively no difference between the two missiles, because their guidance unit is effectively quite similar. You can probably work that one out on paper “

 

I think its fair to paraphrase your firs sentence as “ the % of kills in the zone where the AIM-9 has a 85% chance of hitting it’s target will be the same as the % of kills for the R-73 where it has a 85% chance of hitting its target”

Which is true.

What you’re glossing over is “What you will see is 73's hitting well outside the 9's Pk zone.”

 

The AIM-9 will get LA in (for example - the exact numbers are beside the point) 50% of encounters in a given set of circumstances. With a PK of 85%, ~ 43 of those will be hits.

 

The R-73, because of its larger engagement envelope will launch at 70% of targets given the same set of encounters. With a PK of 85% that means 60 hits.

 

Same PK, same number of encounters, more launches & more hits.

[peterj]

I did some tests to see the difference between the missiles in LockOn. Target is passing at 700 km/h, both missiles where fired when the target reached the center of the HUD (time ~3.8s)

 

Screenshots taken at the same time 5.080/1

 

 

 

The R-73 accelerates faster and turns faster, in this track the R-73 reaches a maximum of 9.8G, aim-9 max 4.3G.

test_fire_aim9_r73.zip

[GGTharos]

Very nice in-game example! :)

 

BTW, Xiathorn, it seems that some in the Russian language forum have decided to make fun of your question - which is amusing, actually.

 

No one considered that the 40kg warhead may be required because of a higher miss distance (which isn't really modelled in the game AFAIK) ... where the 120's warhead keeps shrinking, potentially indicating a shrinking miss distance plus the adaptive warhead ...

[ФрогФут]

peterj

That's because R-73 has VTC(or how is that in English?) engine, like Aim-9X has.

[GGTharos]

Yes, vectored thrust.

 

I believe that when WAFM comes out, R-73 will actually pull -less- G's to accomplish this turn, because of TVC, where the AIM-9M, forced to use aerodynamic turning, will pull more G's.

[D-Scythe]

Fun as it's been - my last post on the matter & pictures paint a thousand words. So regarding turn in rate (G’s in turn) & seekers losing lock because the target is moving too quickly across the seeker’s field of view:

 

http://i16.photobucket.com/albums/b49/weta43/MissileGandLOS.jpg

 

Two missiles starting from the same position relative to their targets & already locked. Both have reached the same constant speed and maintain that speed throughout...

 

...I think its fair to paraphrase your firs sentence as “ the % of kills in the zone where the AIM-9 has a 85% chance of hitting it’s target will be the same as the % of kills for the R-73 where it has a 85% chance of hitting its target”

Which is true.

What you’re glossing over is “What you will see is 73's hitting well outside the 9's Pk zone.”

 

The AIM-9 will get LA in (for example - the exact numbers are beside the point) 50% of encounters in a given set of circumstances. With a PK of 85%, ~ 43 of those will be hits.

 

The R-73, because of its larger engagement envelope will launch at 70% of targets given the same set of encounters. With a PK of 85% that means 60 hits.

 

Same PK, same number of encounters, more launches & more hits.

 

One thing to note about your "greater agility = less strain on seeker" theory. The R-73's greater agility is only really a factor (to the seeker) only in the initial phases of the missile's fly out, because after a few seconds the missile will lose it's TVC after its rocket motor burns out. I don't remember how long the rocket motor burns for the R-73 in LOMAC, but depending on target aspect chances are that TVC would not be available to the R-73 in the terminal phase of its intercept for a large portion of its employment envelope.

[peterj]

I did some more tests, the AIM-120 performs the worst in the above test followed by the R-27ER, R-77 performs similar to the R-73.

 

On the orignal topic, the R-77 comes with the bigest bang, it makes schrapnel out of a Su-27. Could kinetic energy come into play, it arrives at mach 3.

 

Slow down the simulation and watch the G load in missile view.

Anyway WAFM will be interresting.

test_fire_RG.zip

[GGTharos]

The R-77's fins allow it incredible control at high AoA, so it could probably pull of maneuvers resembling those of a vectored thrust missile, just ... not quite!

 

The AIM-120 should ABSOLUTELY be outperforming R-27 in EVERYTHING but range ... thanks for bringing this up.

[Kula66]

The R-77's fins allow it incredible control at high AoA, so it could probably pull of maneuvers resembling those of a vectored thrust missile, just ... not quite!

.

 

But at what cost ... remember by the end game the thing is a glider!!! If it pulls high AOA and it will fall from the sky!

[Kula66]

AFAIK AIM-9 is not really meant to "vaporize" bigger jet planes, rather damage them beyond recovery. SU33 is one big bird, so you would need a sparrow or amraam to really destroy it.

 

Lots of recorded incidents of older Sidewinders breaking smaller planes (Mig-21 class) into pieces when it explodes ... So how much tougher is a 33? Also how much better are the warheads in more modern versions of 'winder?

[S77th-konkussion]

I would suspect it's a helluva lot tougher -simply by virtue of it's carrier capable airframe. It's also a LOT bigger than a Mig 21, yeah?

 

Damn I can't look it up.. at work... bye..

[GGTharos]

But at what cost ... remember by the end game the thing is a glider!!! If it pulls high AOA and it will fall from the sky!

 

But this is only for terminal maneuvering, and close-ranged shots. So the benefit at short ranges should be pretty good in terms of maneuvering to target. It isn't panacea though - it'll work nicely while the motor's burning or the speed is high, but after that ...