Vikhr missiles stop working after a while and nose dive

[fargo007]

I'm seeing some strange behavior occurring randomly.

 

After engaging a few targets, the Vikhrs will no longer track to the target.

 

The Shkval continues to work and lock the target correctly, but when fired, the missile dumps into the ground about 1000M off the nose.

 

Launch criteria observed: 75M AGL, Hover, zero airspeed.

 

This is without touching a single thing after a successful lock/launch/impact.

 

Resetting the laser doesn't fix it.

 

Re-caging and uncaging the Shkval doesn't fix it.

 

Nor does attempting to lock a different target, switching weapons, or anything else.

 

The cannon does still work normally.

 

Once it hits this point, the only solution is to return to the airfield and take a different helicopter. Nothing observed in the DCS.log.

 

I'm pretty sure I'm not missing anything here, but I am not above mistakes. Looking to see if anyone else has observed this.

[lemoen]

You've burnt out your laser. Switch it off between shots. It doesn't have an infinite lifespan.

[Frederf]

Laser can do three activities:

range find

designate laser-seeking weapon

guide Vikhr

 

First two activities require a lot of energy because laser has to go to target and bounce back. They make a lot of heat. Vikhr guidance uses small energy (low heat) so it is not a problem.

 

Range finding happens automatically every time you command Shkval to track "TA" for a few seconds. If you command track very often this can make a lot of heat. To save laser it is best to have laser arm switch close at hand to turn off when moving optical track a lot. Then just before firing arm laser, track again for good range, and then fire.

[fargo007]

ETA - I was able to verify that it is in fact burning out the laser.

 

I reproduced this by firing a boatload of vikhr's and locking the targets over and over again.

 

After the missiles started dumping, I went back and repaired, then they operated normally again.

 

Thanks guys, rep points inbound.

 

/Fargo

Edited March 5, 2018 by fargo007
reproducing

[flanker0ne]

We (as a virtual group) experience this behaviour.

The fancy thing is that at the same time all Ka-50s lost the ability to guide the Vikhr.

 

Is known that the damage system is not very multiplayer friendly

[PeaceSells]

Laser can do three activities:

range find

designate laser-seeking weapon

guide Vikhr

 

First two activities require a lot of energy because laser has to go to target and bounce back. They make a lot of heat. Vikhr guidance uses small energy (low heat) so it is not a problem.

 

Range finding happens automatically every time you command Shkval to track "TA" for a few seconds. If you command track very often this can make a lot of heat. To save laser it is best to have laser arm switch close at hand to turn off when moving optical track a lot. Then just before firing arm laser, track again for good range, and then fire.

 

Thanks for that info!!

[fargo007]

We (as a virtual group) experience this behaviour.

The fancy thing is that at the same time all Ka-50s lost the ability to guide the Vikhr.

 

Is known that the damage system is not very multiplayer friendly

The odds of the same thing occurring to multiple clients at a time obligates me re-question the issue.

I did burn the laser out on reproduction, but the behavior returned, and while unable to guide missiles, the laser did work for the cannon just fine.

[Dr_Arrow]

The odds of the same thing occurring to multiple clients at a time obligates me re-question the issue.

I did burn the laser out on reproduction, but the behavior returned, and while unable to guide missiles, the laser did work for the cannon just fine.

 

AFAIK, cannon does not need laser for guidance, to fire the cannon you need slant range measurement (with laser)/estimation (without laser). Estimation can be done with damaged laser, the system will calculate range of the target using other parameters, but it is a lot less precise than laser ranging. So you can hit targets with cannon without working laser, but range will be only estimated, so less precise.

[Looney]

If it happens again, try returning to the airport, request repairs and when repairs complete, take-off again and try to shoot Vihkrs. If this works, the laser was burned out, if it doesn't work, there is a bug with laser guidance of Vihkrs.

[fargo007]

Good advice Looney.

 

I was just able to get this to happen:

 

1 - Vikhrs start nosediving.

 

2 - The shkval still locks a target and shows range at various distances.

 

3 - The cannon was able to accurately engage targets from 1.5-3K. By accurately I mean no discernible difference from when this issue didn't manifest.

 

4 - Vikhr's still would not guide.

 

5 - RTB, Repair, Vikhr's work again.

 

So apparently the laser is in fact arriving at a condition where it can perform some operations, but not others.

[Rogue Trooper]

Generally after a full load of Vikhrs are fired a good 30 minute cool down is required.

When I did this, the most I have been able to get was two full Vikhrs sorties before failure occurred almost immediately on the third sortie.

 

 

I used the laser very sparingly and waited long time (seconds?) between vikhr launches.

 

 

The Russian 1980s laser is a hunk a junk.... for me this is fine.

[Frederf]

Vikhr laser sensors are in the butt of the missile and follow a dynamic (shrinking over time as missile recedes) railroad of light in the sky. It's very possible for Vikhrs "fall off the railroad" especially immediately after launch. It might be that guidance pattern is there but missile is outside it.

[Reaper6]

You only get 300 seconds of active lasing time. These "seconds" are displayed anytime your laser is initiated, in the bottom left of your HUD. I believe it is 3 seconds everytime you lase a target for range or to lock on a target. The timer for the laser when a Vikhr is fired is dependant on the range of the target(Esteimated time it would take to reach the range+3 seconds). Unless... You have Your laser switch in the "Standby"(Designator) position. Usually used for the Kh-25ml, in which case it will fire for a full 20 seconds--Once you lock the target, NOT when the trigger is pulled like with the Vikhr.

 

 

Things I do to reduce laser use time. Have a switch on your HOTAS or something like that, that way once your Vikhr hits immediatley turn the laser off. Your Shkval does pretty well updating the range using different components of the Ka50. You don't really need to continuously lase the same target over and over(unless it's aircraft). But generally I use Vikhrs first, then go to guns and Rockets. Your laser still has enough energy/cool down to function for a few seconds, after it's "burnt out".

 

 

Usually the 300 seconds is plenty of time for the engagements of all 12 Vikhrs fired seperatley. It's always a good idea just to repair after each sortie anyway, just in case.

 

 

Reaper6

[BaD CrC]

What is strange is that the laser was famously known for not being repairable. Did something changed? Also, Fargo, it is strange that you were able to fire with a burnt laser. I believe you would not be able to get a range and as such, the system would have prevented you from firing.

[Reaper6]

Yeah, you use to have to break something, I always just landed really hard on the front wheel and it would break off. Then they would repair/reset the laser.

 

 

I would dare to guess that the 300 seconds is only for the laser tracking "channel" for Vikhr control. Which I assume produces a lot of heat, so for this instance it would be smart to implement a fail safe into the Ka50. Preventing the laser from being damaged or over heating and only the ground crew would be able to cool it down enough or to reset the time limit.

 

 

The second "channel" of the laser would be strictly for range finding, which produces little to no heat. So it can be used indefinitely.

 

 

Reaper6

[Frederf]

If the laser was dual energy, Vikhr guidance would be low-energy and rangefinding high-energy. But I added temperature to HUD and found that temperature rise per second is equal (close? exact?) for both operation. Vikhr guidance has a higher total thermal energy simply because it is the same rate for longer.

 

Laser temp start 293K rises to 297K during 3s range find decreasing rapidly (-2K/sec?) to ambient. Same with guidance but for the longer times so higher temps, similar recovery. Designator heats very fast, initial time was 44s but seemed to cut out early (6s to go) at 500K.

 

I also lost Vikhr guidance on another run after 24 but before 32 missiles fired. Temperatures never got that high so the stress must not just be exceeding temperature.

 

One thing I did find is that guidance lase time is dependent on estimated target distance which if it's shorter than real distance the laser will simply turn off thinking its job is done when the missile is only half way.

[lobo]

I'm wondering if this "Vikhr gone stupid" problem is related to the new trees? Or is it just is a simulated random failure of the missile?

[PeaceSells]

I'm wondering if this "Vikhr gone stupid" problem is related to the new trees? Or is it just is a simulated random failure of the missile?

 

No, it happens in 1.5 too. And it's not random, it only occurs after long combat and is persistent.

[lobo]

But why then would my very next Vikhr shot guide properly?

[Reaper6]

But why then would my very next Vikhr shot guide properly?

 

You can now hit trees, power lines, and light poles. Which is rather frustrating at first...

 

 

Reaper6

[Frederf]

But why then would my very next Vikhr shot guide properly?

Does that happen? You fire X Vikhrs, X+1 fails, X+2 succeeds?

[fargo007]

The laser is definitely repairable now. I have verified that a few times at this point, so that's a step forward.

 

e.g.

 

1 - Fire a bunch of vikhrs

2 - Laser stops working, vikhrs nosedive.

3 - Repair

4 - vikhrs work again.

 

 

It's also not related to the new trees, because this can be induced repeatably for me in NTTR, specifically around Creech where there are almost no trees at all, no less the new ones.

 

I hear ya on the dual mode laser Frederf, but it is operating the other way around. It ranges 100% fine in this condition (for cannon use, or rangng unguided munitions for example), but won't guide the vikhrs.

[Nooch]

I've already experiencied this 4 years ago in the DCS 1.2 days with the Su-25T. It's definitely not a new thing. What the cause of it exactly is, I'm still unsure... Is it really the laser burning out or something else? Ideally, I'd like to have a few words from the devs themselves otherwise it's just guessing.

Edited March 9, 2018 by Nooch

[Reaper6]

https://en.wikipedia.org/wiki/9K121_Vikhr

 

 

The missile is designed to engage vital ground targets, including armoured targets fitted out with built-in and add-on explosive reactive armor, at a range of up to 8 km when fired from a helicopter and 10 km when fired from a fixed-wing aircraft in daytime and up to 5 km at night, as well as air targets in conditions of air defense assets activity.

 

 

The Vikhr-1 missile is part of the Vikhr-M system, which also includes an automatic sight and a depressible launcher. Adopted in 1990.[8][9]

 

 

The automatic sight is provided with TV and IR channels for target sighting, a laser beam channel for missile control, a laser rangefinder, an automatic target tracking unit, a digital computer and a system for stabilization and aiming the sighting and beam channels. The automatic sight provides for target detection and identification both by day and night, automatic target tracking and missile guidance, and generates exact information for gun and rocket firing. The guided missile consists of a HEAT fragmentation warhead fitted with a contact and a proximity fuze, an air-dynamic control actuator, control electronics, a motor and laser detector. It is kept in a sealed launching transporting container.

 

 

The multi-purpose warhead (two-stage HEAT and an additional fragmentation sleeve) allows the missile to be used against armoured, airborne and area targets alike. This is an advantage compared to the three different missiles required in the 9M120 Ataka-V complex. The use of the proximity fuze allows a near miss of up to 5 m and makes it possible to engage an air target at speeds of 500 m/s.

 

 

The Vikhr missile laser beam control system provides for its precise guidance owing to data transmission to the missile in the course of its launch, which is excluded in homing systems. The Vikhr missile control system has high jamming immunity because its receiver faces the carrier, thereby protecting it from jamming signals.

 

 

The high pinpoint target hit probability (reported 0.95 against stationary targets) is provided by the automatic target tracking system and highly accurate missile control system that makes allowance for changes in the parameters of the carrier and the target in the course of firing.

 

 

The missiles can be fired singly or in pairs (at the same target to increase lethality). The high flight speed allows it to engage targets rapidly. The system is capable of launching Vikhr missiles against two to four targets during a 30-second period and starting at a range of 10 km, which increases its lethality to three to four times that of earlier systems.

 

 

 

From the Manual-Pg 8-8

9. ИУ Beam-riding laser channel is active

10. ПАУЗА ‘PAUSE’ cue - cooling cycle of the laser range-finder in the Target Marker (“ПМ”) targeting mode

12. ТА-ИД Auto-Tracking engaged and the laser range-finder is active

13. ТА-ИУ Auto-Tracking engaged and the beam-riding laser channel is active

 

From the Manual-Pg 13-4

Service limitations of I-251V Shkval

 

Laser rangefinder operation mode for one flight, series: Each series consists of 16 cycles of 10 seconds with 5 sec interval between the cycles.

 

Interval between the series, min: 30

 

Reaper6

Edited March 9, 2018 by Reaper6

[Fri13]

Range finding happens automatically every time you command Shkval to track "TA" for a few seconds. If you command track very often this can make a lot of heat. To save laser it is best to have laser arm switch close at hand to turn off when moving optical track a lot. Then just before firing arm laser, track again for good range, and then fire.

 

That is the way to do it if you are going to operate long times doing recon as you need to measure distances and map the terrain and threats location and types.

But even in the field operations your laser tube would be swapped between firing the 12 Vikhr in few sorties (12*x).

 

There was the mod for the laser temperature in HUD, said to be realistic but not implemented by ED, so the mod just "opened it". And it was fairly nice to check out the ranger.

 

But this error that OP has, has nothing to do with the laser burning out. As I have had that to happen many times constantly at 1.5.x series straight after starting in air or soon after that. Sometimes it fix right away after a restart, sometimes it took couple restarts the mission to get it working.

 

And it was just odd as the missile just did fly 1km and then dropped.