Vikhr M rippling

I seem to remember back in the old days of LOMAC the SU25 could fire multiple vikhrs and you could slew the laser between impacts to hit multiple targets.

It would make sense.

I seem to remember back in the old days of LOMAC the SU25 could fire multiple vikhrs and you could slew the laser between impacts to hit multiple targets.

 

It would make sense.

That is how it used to work in LOMAC/FC1.x. You could ripple fire and move the target box from target to target. Worked great on convoys because, in those days, they kept driving in a straight line after the first hit rather than scattering as they do now.

Rich

I seem to remember back in the old days of LOMAC the SU25 could fire multiple vikhrs and you could slew the laser between impacts to hit multiple targets.

 

It would make sense.

True, but given the fact that the vikhr is a laser BEAM RIDING missile it is (was) highly unrealistic. And thus things changed for the better.

As for getting off multiple vikhrs in a single pass two options

Salvo mode, for when your intention is to hit the same target whit two vikhrs.

Fire, wait for hit, lock new target, rins and repeat till you've shot 2 or 3 vikrs.

Or up to 6 when using salvo mode.

(should be no closer then 3km after doing this if targets are close enough to each other)

The vikhr has its laser sensors in the back of the missile were normally the missiles exhaust is. They have made it this way to make it more resistant to counter measures.

The exhaust of the rocket motor is now trough two holse in the side of the missile.

As can be seen here;

Further, the vikhr has only a single fin at the back of the missile which is moved by an actuator to guide it to the target.

This is the reason of the spiraling flight path when it gets guided to the target.

True, but given the fact that the vikhr is a laser BEAM RIDING missile it is (was) highly unrealistic. And thus things changed for the better.

One step forward, two steps back.

Because by restarting the laser I can double up my Vikhrs just like old time, and there is zero reason for a cooldown between launches when the system is clearly capable of near-simultaneous ripples.

It seems like a glitch and not the intended behaviour to me.

Having only 1 Vikhr in the air at the time is realistic, it's a beam riding missile - one beam, one missile, because the missile blocks the beam it's riding.

Other laser guided weapons (25, 29, S-25L... etc.) are aimed at the laser dot projected onto the target, therefore you can have many weapons in the air at the same time.

Having only 1 Vikhr in the air at the time is realistic, it's a beam riding missile - one beam, one missile, because the missile blocks the beam it's riding.

Not quite, as you can still fire 2 vikhrs in 1 go

maturin,

I completely understand where you're coming from because this phenomenon annoys the hell out of me as well.

The following is a description of the issue. (To avoid confusion, please be aware that I am not talking about ripple firing multiple Vikhrs — I am describing a situation in which I engage two separate targets one after the other, firing one Vikhr at each.)

1. Turn on Shkval and lock target with tracking gate.

2. Select Vikhr and fly aircraft into launch authorised ("LA") parameters.

3. Turn on laser and launch Vikhr (or use auto-laser, whichever).

4. Vikhr rides laser beam and destroys target.

So far so good!

5. Slew Shkval to second target and lock tracking gates. IMPORTANT: Note that the laser is still firing from the previous Vikhr engagement, as indicated by "LR" on HUD.

6. Hold trigger to launch second Vikhr, but nothing happens. This is because there is no LA cue, despite the fact that the laser is firing continuously, the aircraft attitude is nominal, and the Vikhr dynamic launch zone (DLZ) conditions are satisfied.

7. After approximately 8 seconds of holding the trigger, the LA cue mysteriously reappears and the second Vikhr is launched.

Obviously this is not ideal behaviour if you quickly want to prosecute a second target.

However, we can address this issue by altering step 6. If I were first to manually turn the laser off and then on again, the LA cue reappears and I can immediately launch a second Vikhr without waiting for the ~8 second period.

---

So, my question is this: why does this LA cue delay exist? All the necessary conditions are 100% satisfied (attitude, laser, DLZ), so why isn't a launch authorised?

Naturally the Vikhr is a weapon system that typically employs one missile at a time and tracks one target at a time, so I suppose it's plausible that the weapon designers decided that a second launch should not be immediately authorised. However, why is there such a long delay while holding the trigger before the LA cue appears? This delay is a prohibitively long time to wait in order to launch a second Vikhr, especially as the SU-25T will be rapidly gaining speed and will be at risk of overflying the target. In my opinion it is not plausible that this delay corresponds to the predicated time to impact (TTI) of the first Vikhr, because by the time the LA delay has elapsed, the first target has been destroyed for well over 8 seconds.

Furthermore, and most importantly, LA cue delay is simply bad design from the pilot's perspective. If the aircraft and weapon systems are in nominal parameters, a Vikhr launch should be authorised. Period. After all, the pilot is the one who is aware of the tactical situation, and he is more than capable of making intelligent launch decisions. No intelligent pilot is going to spam all of his Vikhrs just because the LA cue tells him he has permission, but he sure as hell may want to quickly engage a second target if it's appropriate for the tactical situation, so the aircraft should let him. That's the pilot's prerogative.

Finally, I don't accept that this is a laser overheating issue. If the laser overheats after firing one Vikhr, the laser symbol in the HUD should flash and tell the pilot such. But it doesn't flash, or make any other indication, so as far as the pilot is concerned he should be able to launch another Vikhr at will. After all, the laser is firing (presumably) and the aircraft is within parameters, so why shouldn't he be able to?

The last nail in the coffin is that the pilot can just turn the laser off and on again to effect an immediate launch. This falsifies the idea that the laser may be an overheating (simply turning the laser on and off will not immediately cool it), and is frankly a poor 'workaround' that needlessly adds switch-flipping complexity, at a critical time when the pilot should be solely focussed on flying the aircraft, launching the Vikhr, and responding to threats.

To sum up:

1. An LA cue delay of this length (or possibly any length) makes no sense. Let pilots make intelligent decisions - the smart ones know damn well when to fire additional Vikhrs and don't appreciate being told otherwise by uppity avionics.

2. If the laser is overheating or has some other 'cooldown' effect (to borrow an MMO term), the pilot should be clearly notified. The LA cue should not simply disappear for no apparent reason without informing the pilot.

3. The 'workaround' of quickly turning the laser off and on again makes no sense if the issue is overheating and cooldown, and additionally adds another unneeded and unwanted step to perform in the heat of combat.

4. If this phenomenon is reflective of the real SU-25T Vikhr/Shkval weapon system, then the designers should be fired.

This definitely seems like a bug to me.

Not quite, as you can still fire 2 vikhrs in 1 go

You can fire them, but you shouldn't be able to guide them both at the same time. The first one would loose guidance as soon as the beam was turned off. However, if the target is static, the missile might hit it even if the beam was off for the last part of its flight.

Not quite, as you can still fire 2 vikhrs in 1 go

See Ka-50 for example.

You can fire them, but you shouldn't be able to guide them both at the same time. The first one would loose guidance as soon as the beam was turned off. However, if the target is static, the missile might hit it even if the beam was off for the last part of its flight.

No, you can fire 2 vikhrs at once, I don't mean by double pressing the trigger, I mean pressing and holding the trigger once using toggle Pairs/Single Salvo Mode.

....but you shouldn't be able to guide them both at the same time....

You are not guiding them - they are guiding themselves. As Kuky said, can fire two on one target.

No, you can fire 2 vikhrs at once, I don't mean by double pressing the trigger, I mean pressing and holding the trigger once using toggle Pairs/Single Salvo Mode.

Haven't tried that - but how do they guide then?

No, you can fire 2 vikhrs at once, I don't mean by double pressing the trigger, I mean pressing and holding the trigger once using toggle Pairs/Single Salvo Mode.

I didn't think salvo size applied to non-free-fall weapons on the Su-25T???

Salvo mode applies to all missiles, bombs and even A2A weapons. The inner pylons on Su-25T are normally rippled single (other outer pylons are always in pairs unless you have asimetrical loadout). If you use Pairs Salvo mode on A2A missiles you if you hold the trigger it will fire 2 missiles.

And how they guide... well the beam is not exactly hair thin, also as the missile is released its off the beam already and with some distance from aircraft it picks the beam up and manouvers to adjust (which is why it doesn't fly fully straight untill it settles)

You also have Ripple Quantaty and INterval, which is usefull if you have loadout of same bombs, and you can sellect if you want to drop pair, 4 or all wepaons of all pylons. Same for when you carry gun pods, you can sellect 2 (which will fire gun pods only) or all (which will fire gund pods and internal gun, but in this case the gun pods don't elevate ad are fixed as interal gun is fixed)

It doesn't seem to work with rockets though.

I didn't think salvo size applied to non-free-fall weapons on the Su-25T???

Check the HUD - a rectangular box surrounding both weapons-stations indicate that the Vihkrs will launch in pairs.

Haven't tried that - but how do they guide then?

The Vikhr rides to the ground enclosed in a laser 'cube' or grid. It manoeuvres to stay within the cube, hence the spiral pattern. If one Vikhr can ride all the way down in the cube, the other can/does too. As I said, you are not guiding them - they are guiding themselves by keeping themselves within the laser grid/cube, utilizing a motor in their tail.

It doesn't seem to work with rockets though.

It works wil rockets also, sellect all pylons (it should show square around all available pylons for that weapon) and when you press trigger it will fire weapons/rockets from all pylons.

Let me be more pecise:

For Vikhrs use Pairs/Single Salvo mode so you can fire 1 or 2 Vikhrs in one trigger press (like in Ka-50)

For bombs use Ripple Quanity and Ripple Interval so you can chose frm how many pylons to drop bombs in one trigger press (and hold)

for rockets you can use Pairs/Single Salvo Mode again so you have option to fire ALL pods or only from 2 (from oposite pylons)

maturin,

 

I completely understand where you're coming from because this phenomenon annoys the hell out of me as well.

 

The following is a description of the issue. (To avoid confusion, please be aware that I am not talking about ripple firing multiple Vikhrs — I am describing a situation in which I engage two separate targets one after the other, firing one Vikhr at each.)

 

1. Turn on Shkval and lock target with tracking gate.

2. Select Vikhr and fly aircraft into launch authorised ("LA") parameters.

3. Turn on laser and launch Vikhr (or use auto-laser, whichever).

4. Vikhr rides laser beam and destroys target.

 

So far so good!

 

5. Slew Shkval to second target and lock tracking gates. IMPORTANT: Note that the laser is still firing from the previous Vikhr engagement, as indicated by "LR" on HUD.

6. Hold trigger to launch second Vikhr, but nothing happens. This is because there is no LA cue, despite the fact that the laser is firing continuously, the aircraft attitude is nominal, and the Vikhr dynamic launch zone (DLZ) conditions are satisfied.

7. After approximately 8 seconds of holding the trigger, the LA cue mysteriously reappears and the second Vikhr is launched.

 

Obviously this is not ideal behaviour if you quickly want to prosecute a second target.

 

However, we can address this issue by altering step 6. If I were first to manually turn the laser off and then on again, the LA cue reappears and I can immediately launch a second Vikhr without waiting for the ~8 second period.

 

---

 

So, my question is this: why does this LA cue delay exist? All the necessary conditions are 100% satisfied (attitude, laser, DLZ), so why isn't a launch authorised?

 

Naturally the Vikhr is a weapon system that typically employs one missile at a time and tracks one target at a time, so I suppose it's plausible that the weapon designers decided that a second launch should not be immediately authorised. However, why is there such a long delay while holding the trigger before the LA cue appears? This delay is a prohibitively long time to wait in order to launch a second Vikhr, especially as the SU-25T will be rapidly gaining speed and will be at risk of overflying the target. In my opinion it is not plausible that this delay corresponds to the predicated time to impact (TTI) of the first Vikhr, because by the time the LA delay has elapsed, the first target has been destroyed for well over 8 seconds.

 

Furthermore, and most importantly, LA cue delay is simply bad design from the pilot's perspective. If the aircraft and weapon systems are in nominal parameters, a Vikhr launch should be authorised. Period. After all, the pilot is the one who is aware of the tactical situation, and he is more than capable of making intelligent launch decisions. No intelligent pilot is going to spam all of his Vikhrs just because the LA cue tells him he has permission, but he sure as hell may want to quickly engage a second target if it's appropriate for the tactical situation, so the aircraft should let him. That's the pilot's prerogative.

 

Finally, I don't accept that this is a laser overheating issue. If the laser overheats after firing one Vikhr, the laser symbol in the HUD should flash and tell the pilot such. But it doesn't flash, or make any other indication, so as far as the pilot is concerned he should be able to launch another Vikhr at will. After all, the laser is firing (presumably) and the aircraft is within parameters, so why shouldn't he be able to?

 

The last nail in the coffin is that the pilot can just turn the laser off and on again to effect an immediate launch. This falsifies the idea that the laser may be an overheating (simply turning the laser on and off will not immediately cool it), and is frankly a poor 'workaround' that needlessly adds switch-flipping complexity, at a critical time when the pilot should be solely focussed on flying the aircraft, launching the Vikhr, and responding to threats.

 

To sum up:

 

1. An LA cue delay of this length (or possibly any length) makes no sense. Let pilots make intelligent decisions - the smart ones know damn well when to fire additional Vikhrs and don't appreciate being told otherwise by uppity avionics.

2. If the laser is overheating or has some other 'cooldown' effect (to borrow an MMO term), the pilot should be clearly notified. The LA cue should not simply disappear for no apparent reason without informing the pilot.

3. The 'workaround' of quickly turning the laser off and on again makes no sense if the issue is overheating and cooldown, and additionally adds another unneeded and unwanted step to perform in the heat of combat.

4. If this phenomenon is reflective of the real SU-25T Vikhr/Shkval weapon system, then the designers should be fired.

 

 

This definitely seems like a bug to me.

Will someone address this rather excellent post?

Why do we have to restart the laser?

Because;

Vikhr rides a beam to the target.

This beam is a grid of a certain size that the vikhr tries to stay within.

Upon launch, the grid is pretty big so the vikhr's sensors will pick it up sooner and start guiding.

Upon closing to the target the beam gets smaller to ensure its accurate enough.

You can't fire another vikhr cause as the targeting system is concerned there is still one in flight, and thus its firing a narrow beam.

Firing a vikhr at this point anyway would likely cause it not to track cause there's a pretty big change it will miss the laser beams grid.

Turning laser off resets the firing sequence for the laser, so that when a vikhr is fired again it starts of whit a big grid again to ensure the missile fly's into it.

Hence its not a bug, its a feature

(this was explained here on the forums a long time ago ill see if i can find it)

Because;

 

You can't fire another vikhr cause as the targeting system is concerned there is still one in flight, and thus its firing a narrow beam.

But there ISN'T one in flight. Is the FCS not capable of realizing when it no longer has laser contact to a missile? If the Shkval can track a helicopter, why can't it track its own Vikhr?

Is the FCS not capable of realizing when it no longer has laser contact to a missile?

No, how would it? There is no contact to begin with.

If the Shkval can track a helicopter, why can't it track its own Vikhr?

You do not understand how the Vikhr operates. There is firstly a distinction between the laser rangefinder and the laser grid the Vikhr utilizes to guide: Two separate and distinct lasers, which, apart from range, probably has nothing to do with Shkval tracking in any event - definitely so in the case of the laser grid the Shkval projects for the Vikhr.

The Vikhr is autonomous - is not being guided. It manoeuvres so as to keep itself flying within the laser 'cocoon' until impact - nothing more.

It works wil rockets also, sellect all pylons (it should show square around all available pylons for that weapon) and when you press trigger it will fire weapons/rockets from all pylons.

 

Let me be more pecise:

 

For Vikhrs use Pairs/Single Salvo mode so you can fire 1 or 2 Vikhrs in one trigger press (like in Ka-50)

For bombs use Ripple Quanity and Ripple Interval so you can chose frm how many pylons to drop bombs in one trigger press (and hold)

for rockets you can use Pairs/Single Salvo Mode again so you have option to fire ALL pods or only from 2 (from oposite pylons)

Ah, cheers. I don't think I've ever carried more than 2 pods, so I probably wouldn't have noticed.

No, why would it? It doesn't know anything about the missile other than the fact that you launched one.

But there ISN'T one in flight. Is the FCS not capable of realizing when it no longer has laser contact to a missile?

Because it's tracking your target (among other reasons).

If the Shkval can track a helicopter, why can't it track its own Vikhr?

Because;

Vikhr rides a beam to the target.

This beam is a grid of a certain size that the vikhr tries to stay within.

Upon launch, the grid is pretty big so the vikhr's sensors will pick it up sooner and start guiding.

Upon closing to the target the beam gets smaller to ensure its accurate enough.

You can't fire another vikhr cause as the targeting system is concerned there is still one in flight, and thus its firing a narrow beam.

Firing a vikhr at this point anyway would likely cause it not to track cause there's a pretty big change it will miss the laser beams grid.

 

Turning laser off resets the firing sequence for the laser, so that when a vikhr is fired again it starts of whit a big grid again to ensure the missile fly's into it.

 

Hence its not a bug, its a feature

 

(this was explained here on the forums a long time ago ill see if i can find it)

OK, I didn't know about the enlarged laser "grid" at launch that facilitates the 'capture' of the Vikhr (so to speak), and I didn't know that the grid transitions to a finer beam when impact is near. From a practical real-world perspective it totally makes sense. Thanks for the explanation.

However, I still think that the laser resetting system is poorly designed. Taking your explanation into consideration, I don't understand why the LA cue needs to be delayed for such a long time. To explain, surely the fire control computer must have a rough idea of a Vikhr's time to impact from the moment of its launch, otherwise how else would the FCC calculate a DLZ? Moreover, how would it know when to focus the laser beam? I suppose it could just be a matter of focussing the laser at some arbitrary point after 'capturing' the Vikhr, but that still doesn't address how the DLZ could be used to obtain a reasonably accurate TTI.

At present, the LA cue delay for a second Vikhr is pretty darn long, in the order of ~12 seconds after the impact of the first Vikhr. As I now understand, this delay is caused by the system waiting for the laser grid 'cycle' to finish guiding the first Vikhr, but once again, I find it hard to believe that the FCC can't compute a TTI to speed this process up. Even with a buffer in place, a TTI should allow the FCC to reset the laser much sooner than 12 seconds and authorise a speedier second launch. I mean come on you stupid laser, 12 seconds is the time it takes one Vikhr to impact when fired at max range! (Note: I am aware that the DLZ can be overidden to launch Vikhrs at longer ranges. I'm not considering that scenario. If a launch override occurs, the best way to address the laser issue would be to have it fire continuously until the pilot manually resets it.)

I don't pretend to understand the complexities of all the variables that would make up a TTI calculation, but they are all bound by physics and thus are amenable to calculation. The aircraft's speed, it's altitude, slant range to target, the burn time of the rocket motor and the missile's aerodynamics, I would have thought these are all things that can be approximated and used to produce something with an error bar of less than 12 seconds. As I mentioned in a previous paragraph, if this can't be done, how else is the DLZ calculated? Is the DLZ's accuracy that coarse?