Su25T - Vihkr accuracy

[Razi]

There is one particular mission in the Su-25T campaign that I have trouble with the accuracy of Vihkrs. In this particular mission, my Vihkrs hit at about a 50% success rate. Whereas in all other missions I've ever played it is almost 100% accurate.

 

The way the campaign works is that there are multiple missions for the same stage of the campaign and you never know which one your going to get. If I happen to land this particular one, I always know because my Vihkrs are inaccurate. Whereas if I get any of the others for the same stage, they are accurate as usual.

 

Any ideas? I thought that perhaps wind is an issue, so in the mission I've approached from different directions, but with the same inaccurate result.

 

 

I have a trk that is big and is giving me troubles uploading (due to missing security token??), so I've embedded a sample Youtube clip of the mission here:

 

[MadDog-IC]

There is one particular mission in the Su-25T campaign that I have trouble with the accuracy of Vihkrs. In this particular mission, my Vihkrs hit at about a 50% success rate. Whereas in all other missions I've ever played it is almost 100% accurate.

 

The way the campaign works is that there are multiple missions for the same stage of the campaign and you never know which one your going to get. If I happen to land this particular one, I always know because my Vihkrs are inaccurate. Whereas if I get any of the others for the same stage, they are accurate as usual.

 

Any ideas? I thought that perhaps wind is an issue, so in the mission I've approached from different directions, but with the same inaccurate result.

 

 

 

Bit hard to help if you don't mention the specific mission name or number (should show up in briefing), knowing this would allow me to investigate or fly the mission to see if I have the same issue.

 

I have had this issue before myself, I don't think it is a wind problem in the video because:

 

• The vikhers is flying dead straight, not following the laser in a corkscrew pattern, if it was wind it would still follow the laser for a certain time until it was blown further away from the laser beam so that it could not track it anymore and missile would just go rogue.
  
• The issue is more likely due to low light conditions and atmosphere or laser failure, as the vihkers isn't capable of seeing the laser, because the beam isn't being projected onto the target or that the vihkers seeker isn't capable of seeing the reflected beam due to poor contrast due to too low a light or refraction of the laser beam through fog, haze, rain, etc and simply can't see or follow the laser beam to target.
  

Regards, Ian.

[Razi]

Oh I did forget the mission details, my bad.

 

It is the first mission of the Georgian Oil War campaign titled ATO A.03.4.

 

Weather factors might make sense, though the overcast weather looks the same to me in all the variants of the first mission that I've flown. I do notice a large amount of side slip in the problem mission. The odd thing is that the aircraft slips in the same direction no matter what direction I'm flying. That is perhaps completely unrelated though.

[MadDog-IC]

Oh I did forget the mission details, my bad.

 

It is the first mission of the Georgian Oil War campaign titled ATO A.03.4.

 

Weather factors might make sense, though the overcast weather looks the same to me in all the variants of the first mission that I've flown. I do notice a large amount of side slip in the problem mission. The odd thing is that the aircraft slips in the same direction no matter what direction I'm flying. That is perhaps completely unrelated though.

 

Looked in the mission editor, and weather effects are quite similiar to the other 3 alternate missions in that stage, the only thing reasonably different between the 4 missions are:

 

• Season is mainly Fall but can be Spring
  
• Cloud thickness and density - Very overcast
  
• Wind directions and strength, but there are very high winds of 8 - 15ms.
  

So I would conclude that it is both a colmination of poor light and high winds causing the issue, as some of the KA-50 missions I have been fixing have the same issue with very similar conditions in the missions.

 

Cheers Ian.

[Stuge]

Vikhr seems to not track. I usually aim so that I put the target in the bottom edge of the aiming circle, this way the missile doesn't have to pull up at all after launch so it's more reliable, I think the aim circle is not aligned perfectly. When fired from closer than max range (like in the video also) any misalignment can lead to missile to oscillating and missing or even losing track completely like in this case... or it may be another reason I don't know about :)

[Razi]

I think the aim circle is not aligned perfectly.

 

Could be, however I've never noticed a sensitivity to the alignment of the pipper before or range. I just flew a multiple Vihkr pass and it seems very forgiving. I'm very curious about the weathers affect on the laser, because as you noted the Vihkr doesn't seem to track at all, from the moment it is fired. So like MadDog says, it does not appear to be a wind issue, but perhaps a lighting/overcast conflict.

 

I flew the same campaign mission again and, though I missed a fair bit, I did find I could increase the accuracy a bit by firing at a closer range. This became problematic however... In the end I found that I had to be prepared to fire two Vihkrs each run as I had no idea if the first was going to hit, but the second Vihkr did hit every time.

 

This run is more typical of the accuracy and forgiveness, at any range, of Vihkrs in my experience:

 

Edited April 24, 2016 by Razi

[BinaryMan]

What you are experiencing is a failure for the vihkrs to successfully find and maintain the laser your aircraft emits. Currently in 1.5.3.52478 the release reticle for the vihkrs performs poorly in cross winds. Additionally, even in the no wind condition vihkrs mainly enter the bottom portion of the laser beam. I have created a youtube playlist with the vihkrs in 3 wind conditions. no wind, 4 m/s left crosswind, 8 m/s left crosswind.

 

 

My advice is as follows. Avoid crosswinds when using vihkrs if possible. In cross winds greater than 4m/s always launch high and upwind as necessary.

I should also note, that sometimes you might find the the release queue for the launcher that is down wind will work while the upwind vihkr launcher doesn't.

 

I'm unsure if this is a bug with the su25t or not. Wouldn't be surprised either way.

Edited April 24, 2016 by BinaryMan

[xaoslaad]

Bit hard to help if you don't mention the specific mission name or number (should show up in briefing), knowing this would allow me to investigate or fly the mission to see if I have the same issue.

 

I have had this issue before myself, I don't think it is a wind problem in the video because:

 

• The vikhers is flying dead straight, not following the laser in a corkscrew pattern, if it was wind it would still follow the laser for a certain time until it was blown further away from the laser beam so that it could not track it anymore and missile would just go rogue.
  
• The issue is more likely due to low light conditions and atmosphere or laser failure, as the vihkers isn't capable of seeing the laser, because the beam isn't being projected onto the target or that the vihkers seeker isn't capable of seeing the reflected beam due to poor contrast due to too low a light or refraction of the laser beam through fog, haze, rain, etc and simply can't see or follow the laser beam to target.
  

Regards, Ian.

Vihkr's have their sensor in the back of the missile. They're beam riding and look back at the chopper/plane instead of forward at a reflection on the target. They're virtually impurvious to jamming for this reason. Lasers also don't have a problem operating at night. Other sensors like the Shkval may not be able to lock, but if you can make out the target and steady the laser on the target or use the LLTV they're fine. Besides which, I sincerely doubt any form of refraction is modeled in the game.

 

Sent from my SAMSUNG-SM-G870A using Tapatalk

Edited April 25, 2016 by xaoslaad

[Kamov Akula]

Also having problems Su25T Vikhrs'

 

I just found this recent thread as I came here frustrated by the vikhrs. I just had a run where out of 6 shots 6 missed, usually dropping way short.

 

The mission where it most often happens is the first one in the Georgian Oil War campaign. The OP's sample youtube video I think shows that exact mission.

 

This happens often, most prominently in the first mission of said campaign. It just happened so consistently just now that it motivated me enough to come to the forums about it for the first time (or, I may have posted about it once before). Usually there will be 1, 2, or 3 consecutive misses for one hit in that particular situation. 6 consecutive misses really got me flipping tables.

 

I have no idea why this is happening, but it really affects my game. At first I thought it may be low light, because it usually happens when the virtual environment is cloudy or getting dark, but laser guided weapons should work even in the dark, like xaoslaad said, is that correct? Certainly the other laser guided weapons like the 29L, 25L, or 25mu works just fine even when I'm having problems with the Vikhr.

 

It's gotten to the point where I often replace Vikhr's with a pair of 25L's or 25mu's since at least they hit.

 

Edit:I read the post about the crosswind. Having doubts if that's actually what's happening, but will explore. If so, my next query is whether it's a bug or that's how vikhr's are in real life. Having doubts about it being that finicky IRL, it was Russia's premier AT weapon for a long time and if it failed to hit 50% or more because of a little crosswind I'm sure it would have been soon fixed or replaced....

Edited May 30, 2016 by Kamov Akula

[ShuRugal]

Edit:I read the post about the crosswind. Having doubts if that's actually what's happening, but will explore. If so, my next query is whether it's a bug or that's how vikhr's are in real life. Having doubts about it being that finicky IRL, it was Russia's premier AT weapon for a long time and if it failed to hit 50% or more because of a little crosswind I'm sure it would have been soon fixed or replaced....

 

I don't fly the Frog much, but I've over 1k hours with the KA-50, and I can confirm that any strong crosswind will make the launch reticule very inaccurate. If there is a strong crosswind, I try to line up my attack either in-towards or away from the wind. If i cannot do this, I have to add enough translating component to my motion that i am not sideslipping aerodynamically, even though this may have me going 50 kph sideways over the ground.

 

The problem is caused by the vikr guidance cone being very narrow. In high crosswind, it does not take much sideslip to throw you off; the missile is much lighter than your aircraft and is very responsive to the wind. the OP's video is a textbook case of "missile missed guidance cone".

[Kamov Akula]

Ok. I fly the ka50 mostly too, but with that the crosswinds start affecting the aircraft before I can even start shooting the vikhrs, so that may be why i didn't notice it much flying that. If that's how they are supposed to be then I can at least stop being frustrated and start thinking about other solutions. That is one thing about simulations, the more accurate they are its hard to tell sometimes if it's a flaw in the design of the game or a flaw (or limitation) in the design of the simulated object irl....

 

thanks for input

[Razi]

The latest DCS update changelog (DCS 1.5.4.54855) has this little nugget:

 

ATGM Vikhr will not be drop out of guidance channel with sidewind

 

I'll try to do some testing to see if this changes anything.