Questions about real Vikhr missile guidance

[mandoble 1]

This one is laser guided in AA mode too, right? So flares would not have any effect of them, but the pilot should keep the lock on the target until miss or impact, correct?

Also, its flight patter is always direct aproach to target, right? Or does it use different flight patterns depending on target type (air or ground)?

[whisper 0]

Vikhr is laser guided, but it's a beam riding missile with a single govern (eng word?)

ie : the pilot locks on target, so that a laser beam goes from plane to target.

The missile is launched. The laser detector is on the back of the missile, and the missile flight logic tries to keep its detector inside the beam.

Using this technique, the missile "rides the beam", right into the target.

where things get complicated : the missile has only 1 ... I don't know how to say in english... well, the Vikhr can't be maneuvered in every direction, only one. Let's say, it can only turn "right" (or clockwise, seen from behind). So if the missile quits the beam from the right side and needs to turn left to go back in the beam, it will need to make a whole 180° right "turn" (a spiral).

this results in a typical spiral flight pattern for the missile around the laser beam

The ground/air target switch doesn't govern the flight pattern per se, AFAIK. It does 2 things :

- in ground mode, the fuze is impact, in air mode, the fuze is proximity (ie the missile will explode without needing to hit).

- (not sure about this at all) in ground mode, the laser goes right on target. In air mode, the laser leads the target (targets in front of the actual target to predict its movement)

Edited August 18, 2009 by whisper

[cjsoques 0]

Vikhr is laser guided, but it's a beam riding missile with a single govern (eng word?)

ie : the pilot locks on target, so that a laser beam goes from plane to target.

The missile is launched. The laser detector is on the back of the missile, and the missile flight logic tries to keep its detector inside the beam.

Using this technique, the missile "rides the beam", right into the target.

where things get complicated : the missile has only 1 ... I don't know how to say in english... well, the Vikhr can't be maneuvered in every direction, only one. Let's say, it can only turn "right" (or clockwise, seen from behind). So if the missile quits the beam from the right side and needs to turn left to go back in the beam, it will need to make a whole 180° right "turn" (a spiral).

this results in a typical spiral flight pattern for the missile around the laser beam

I've always wondered why the Vikhr did that in DCS Black Shark thanks, I guess they did to simplify and reduce moving parts on the missile or for easier guidance making it cheaper. Does it behave this way at all in ARMA2, I'd be shocked because that is a detail you'd only notice in something as hi-fidelity as DCS.

I guess what you are trying to say, is that is has only one guidance control axis of correction? The missile seems to have the fins angled to have a set rotational speed for directional stability but also when it hits a certain rotation angle there is only one fin movement direction to correct the path to the beam? If that makes any sense :)

Anywho, yeah the Vikhr does not have an IR sensor so flares are useless, however I recall it being very cheap and not very maneuverable and not ideal for fast moving targets at all.

[Hunin 0]

Correct.

The Vikhr is a laser beamrider with a consequently low tolerance zone for stearing it in flight.

No LOAL, no LOBL.

Only direct sightline and constant beam with all it's implications ( no heavy weather, not much room for f'ups at standoff range etc. ).

Since it is very fast and programmable to detonate in proximity it's chances to hit a relativly stationary air target ( unaware utility helicopters f.e. ) are not totaly crap.

edit

Yes cjsoques, the idea was to keep the cost down.

The missile itself has only one movable fin to adjust course inflight, "deflecting" the rotation to a direction and dampening it again once solidly on the beam again.

Edited August 18, 2009 by Hunin

[whisper 0]

Since it is very fast and programmable to detonate in proximity it's chances to hit a relativly stationary air target ( unaware utility helicopters f.e. ) are not totaly crap.

:D:D Best way to describe it I've read so far :)

[spooky lynx 73]

In anti-aircraft "mode" Vikhr can be fitted with HE-Frag warhead and proximity fuse. Its speed is about 610 m/s, so even with laser-guide system missile hits the target in some seconds.

[cjsoques 0]

Correct.

The Vikhr is a laser beamrider with a consequently low tolerance zone for stearing it in flight.

No LOAL, no LOBL.

Only direct sightline and constant beam with all it's implications ( no heavy weather, not much room for f'ups at standoff range etc. ).

Since it is very fast and programmable to detonate in proximity it's chances to hit a relativly stationary air target ( unaware utility helicopters f.e. ) are not totaly crap.

edit

Yes cjsoques, the idea was to keep the cost down.

The missile itself has only one movable fin to adjust course inflight, "deflecting" the rotation to a direction and dampening it again once solidly on the beam again.

Sweet, yeah in DCS (sorry to get off of ARMA2) I've taken out air targets that are either flying away or flying towards me but not if perpendicular to my flight path, the missile never seems to be able to course correct well enough, even fast moving ground targets at close range is iffy if they are moving perpendicular to my flight path.

Thanks for the summary, and does anyone know if this behavior is modeled in any way in ARMA2..usually fly western air vehicles and haven't done much with the eastern ones except in DCS.

[frederf 0]

The Vikhr's companion laser guidance asset on the launching platform actually projects a laser grid pattern for guidance. The missile can see where it is on the grid and steers accordingly.

It only has one maneuver axis (fin set on the back) so it can only fly up/down when vertical or left/right when horizontal. The aerodynamics of the missile are such that it rotates slowly in flight and corrections left/right/up/down are made by the single axis. The result is the classic spiral flight path which does limit it's use a very slight angles.

In real life it's pretty much like a TOW missile in operation. Redirecting the missile is only really possible maybe 30 degrees overall and it's pretty easy to fall off the beam, especially during the time between launch and beam acquire so you have to fly pretty straight and gentle while firing. There are detonation sensor settings for ground (impact), aircraft (proximity), and aircraft coming head-on (proximity detonates sooner).

[mandoble 1]

Thanks guys, I think I have all these features mostly implemented in Mando Missile (except the spiraling path) now I'll try to configure a realistic one for A2.

[frederf 0]

Do you know how much we love you Mandoble?

[Binkowski 26]

Do you know how much we love you Mandoble?

Lots.

[Sleek78 0]

i was hoping that the AT-pods and Vikhr missiles have spiral flight behavior in Arma2 ..too bad they dont !

[mandoble 1]

Another question, any idea about maximum deviation degrees between lased target and missile launcher heading for the missile to be able to get into the bean?

[frederf 0]

It's not super big a window. The launching platform's FCS won't allow a shot unless the target is within some rather narrow launch constraints however. If you're flying directly toward or away from the target it's pretty much impossible to have the missile not "catch" on the grid.

The biggest contributors to the missile not catching on the grid is a large lateral component of movement and/or pretty extreme yaw rates. Conservatively speaking I'd say +/- 10° cone laterally and no limit vertically (as the Vikhr launcher usually pivots on the hardpoint).

[mandoble 1]

Thanks Frederf, dindt know the Vikhr launcher was able to pivot.