9K121 Vikhr launch, is this realisticaly simulated?

I've thought about this on an off for several years.

I've been a keen user of the Ka-50 even before DCS world.

Something that has always struck me as strange is the need to turn the helo a little during Vikhr launch.

On the surface it seems reasonable as it's a beam riding missile.

But dig a little deeper and there are 2 significant issues.

First is that turning the nose left to line up a launch tube on the right outer has the seemingly adverse effect of the source of the laser moving to the left, and increasing the angle between the laser and missile.

It would just about seem more intuitive if the tube were angled inward slightly toward the nose and the helo turn the launching tube away from the target slightly so as the missile can acquire and ride the beam with less incidence.

However going further is the fact the Shark can launch a missile from each side in salvo mode and both have no issue capturing and riding the beam.

It begs the question, what source is the information with regards to this?

Do DCS have an accurate, un classified source or is it one of those things implemented as a best guess (which is totally fine by the way, sometimes it has to be)?

In case the above is unclear I've had a doodle in paint, sorry, I'm no artist.:doh:

Afaik you have to turn left for the right tube so you increase the angle between the missile flight path and the beam. Pointing the missile tube more towards the helo would increase imho the risk of damage to the helo.

About the information that ED used: I remember reading something about interviews with Kamov engineers and test pilots the devs had and even visiting the plant where the Ka-50s were build. Can't find the post quickly unfortunately :/

About the salvo questions I would also be very interested in how this works.

The Vikhr has a spiral flight path and it doesn't like making turns.

If you aim right with the right launcher active, the missile would attempt to make a very sharp left turn immediately, which it can't really do. It will go into a (wide) spiral and bleed off a lot of energy while trying to catch the beam.

Near maximum range this could cause your missile to fall short or miss. Too far off target and the missile might just loose the laser completely and impact randomly, causing collateral damage.

As I see it the launch cue ensures the missile has the best flight path possible and the laser offset is less of a concern.

The Vikhr has a spiral flight path and it doesn't like making turns.

 

If you aim right with the right launcher active, the missile would attempt to make a very sharp left turn immediately, which it can't really do. It will go into a (wide) spiral and bleed off a lot of energy while trying to catch the beam.

Near maximum range this could cause your missile to fall short or miss. Too far off target and the missile might just loose the laser completely and impact randomly, causing collateral damage.

 

As I see it the launch cue ensures the missile has the best flight path possible and the laser offset is less of a concern.

But what about salvo launch then? :huh:

The launch tubes are parallel to the center line of the helo.

Say you're pointing straight at your target, and you launch your missile, it will make an "S-curve" to capture the laser, losing some of it's energy. This is the case in a salvo launch. The maximum range will be slightly less than a single Vikhr launch.

In a single Vikhr launch, you slightly tilt your "launch platform" to make it intercept the laser beam, by nature of throwing the missile into the intercept path, thus making the launch slightly (for lack of a better worde) "better". You lose a little less energy in capturing the beam. This only really becomes relevant/important at the maximum range.

I should also point out that the range you use Vikhr's is usually 4-9km. A tiny bit of offset during initial launch is not going to make a great difference. You can even loft the Vikhr's in manual firing mode and they'll gain a bit of extra range while picking up the laser just fine.

I should also point out that the range you use Vikhr's is usually 4-9km. A tiny bit of offset during initial launch is not going to make a great difference. You can even loft the Vikhr's in manual firing mode and they'll gain a bit of extra range while picking up the laser just fine.

9km?! Since some update I wasn't able to get it beyond 8.4km in an appropriate altitude. From which altitude do you fire for 9km?

I just tested it and you're right. At sea level hovering at 12m shooting at a target also at sea level, I can only get 8.0-8.1km before the Vikhr hits the ground.

What I "try" to do, terrain permitting... is set up my attack from a hill-top about 8-10KM from the target site. with enough elevation you can kill targets out to about 10KM.

But what about salvo launch then? :huh:

What about it? You point your nose at the target, both launchers will be (mostly) aligned and you shoot. The Vikhr can handle the few degrees.

The original post talks about putting the Shkval and launcher in one line, which would require significant turning of the helicopter. A Vikhr fired at such angles might still work but it's gonna waste a lot of energy flying a large spiral after launch.

There's actually a few really good posts on this on the Russian forums.

If the launchers were canted in just half a degree or something it sounds like it would solve all problems.

I'm sure ED do the best they can, but some things will not be accurate due to lack of information or due to mistakes.

I suspect that in the real life scheme of things the turning one way or another makes no measurable difference.

But here is the most important point.

The manual says this turn is needed to help the missile acquire the beam between its rear sensors.

The turn suggested in DCS would seem to be an inefficient way of achieving this if the missile makes an S turn at launch regardless.

Additionally you'd be shooting the missile across the beam more so than nearing parallel to the beam.

So by the book it doesn't stack up.

Regarding info in the Russian forum, any links would be appreciated just to get started, I'll use a translator from there.

It's a pity auto turn to target doesn't account for this. Unless you set manual firing mode, you constantly have to kick the rudder to line up the shot.

The beam is shaped when guiding.

The missile distance from the helicopter is calculated by time, based to missile speed.

In a such way that the laser beam is 7 meters diameter at the missile position, and the strength of laser is as well adjusted so it will get stronger further time goes.

When launching the salvo, the laser guidance is started only when the second missile launches, so the first one is flying moment without seeing laser beam. If you release launch trigger so you don't launch second missile, laser guidance is never started.

This laser beam shaping and strength adjustment helps for few things.

1) Target can't detect the laser energy focusing at it with laser warning systems because the energy is low powered and very widely shaped. So just couple seconds before impact there is change that LWS could alarm the vehicle crew from laser emission, before missile impacts.

2) the thermal generation stays in control, as shorter timed beaming is less heating, as well lower power at early stage as well keeps heat generation better under control.

Now, the old KA-50 (Black Shark 1) had the shkval targeting ring as big, that didn't require so much aiming aside, more about straight ahead. But they changed it to very narrow one.

again wonder that why it was made so big in first place?

@Fri... what?… Where did you get that from?

Iam just asking because of what i know some things agree with what you have written .. an a few not.

The beam shaping thing is common with other beamriding missiles.

@Fri... what?… Where did you get that from?

 

Iam just asking because of what i know some things agree with what you have written .. an a few not.

That is explained IIRC in the KA-50 manual. Or then it was some KA-50 documentary videos or so.

@Fri... what?… Where did you get that from?

 

Iam just asking because of what i know some things agree with what you have written .. an a few not.

If you look on the Russian forums, you'll find some in-depth discussions and quotes from Russian books on it. Much more detailed than the debates here.

There's a thread or two that I started there as well, looking for more information on this. Got some good answers.

Iam just wondering about the salvo modes first missile not being guided when there is no follow up missile?

Is this only the case in Automatic mode?

Because in Manual mode i can fire Vikhr missiles with an time gap of up to 5 seconds?!? And thats possible since 2008.

:dunno:

I think there was some discussion of this in the Russian forum. I can't remember. I guess the computer can adjust the laser cone in certain ways to adjust for multiple missiles in it, at once. In auto, it's one missile right after the other, so no problem. With big spaces between them, that's going to be a lot more complicated for the fire control computer to deal with. I'm sure there is a limit eventually, as the cone has to expand once again every time another missile is fired, in order to catch it in the cone.