Question about the Vikhr missile...

[Jason76]

Does anybody know why the missile begins that crazy looping movement after launch? Was it purposely designed to function as thus, and wouldn't a straighter flight path to the target be more energy efficient? I don't know a whole lot about physics, but it seems that a straight line to the target is the best one. Anyways, I'm just curious about it - the missile is quite effective at what it does regardless.

[Cobra360]

IIRC it's to do with the missile only having one turning actuator because of the missile's small size. It can only turn in the same direction to correct it's flight path andd thus needs to be constantly corrected and ends up in a spiral.

[Force_Feedback]

Does anybody know why the missile begins that crazy looping movement after launch? Was it purposely designed to function as thus, and wouldn't a straighter flight path to the target be more energy efficient? I don't know a whole lot about physics, but it seems that a straight line to the target is the best one. Anyways, I'm just curious about it - the missile is quite effective at what it does regardless.

 

The missile only has one controllable axis (only one set of moving vanes), in order to fly up-down/left-right the thing needs to do some revoloutions. I do agree that the loops in the beginning are overexaggerated, as other antitank missiles don't appear to have such wide loops in the boost stage. The real vikhr isn't that smokey either, as are its loops smaller than those in lomac. As seen the in ka-50 video, and the ka-50 is 4x slower than the su-25t, so the loops on the 25t should be even smaller in diameter, as the missile already got a beginning speed. But missiles lack AFM for now.

[D-Scythe]

As seen the in ka-50 video, and the ka-50 is 4x slower than the su-25t, so the loops on the 25t should be even smaller in diameter, as the missile already got a beginning speed. But missiles lack AFM for now.

 

Actually, the loops should be the same diameter, it's just that the forward "length" of each revolution is so much greater (since the -25T is already at speed) that it gives the impression of having a smaller diameter.

[Hawg11]

Hmm. I guess I just assumed that the Vikhir had a spiral flight path for the same reason that early Aim-9 versions would fishtail. The Aim-9 was originally called a sidewinder because the gimbal limit of the seeker head prevented it from looking dead ahead, thus the squirrely flight path. This, of course, was corrected in later versions.

[GGTharos]

Not a gimbal limit issue ... it's the way the seeker is built, the receiver is placed in front of the mirror which is looking at the target, which eclipses the center.

 

The same problem newtonian telescopes suffer is you attempt to look at something really close. ;)

[Hawg11]

Not a gimbal limit issue ... it's the way the seeker is built, the receiver is placed in front of the mirror which is looking at the target, which eclipses the center.

 

The same problem newtonian telescopes suffer is you attempt to look at something really close. ;)

 

Hi GGTharos, to which missile are you referring to?

[GGTharos]

The Sidewinder. I have a document somewhere on my HD describing certain simulation methods or -something- concerning this type of seeker if you want it, but it's pretty dry. And ... well, I -hope- I have it still anyway.

[Hawg11]

Yes please. :)

 

At least according to this, it seems we were both a bit off.

http://www.geocities.com/CapeCanaveral/Hangar/6846/aim-9.html

"The Sidewinder got its name from the fact that in early tests, the IR seeker was in a fixed mounting slightly off the missile's centerline, so when the missile spun in flight the target appeared to move, from the missile's point of view, causing it to constantly issue course "corrections" to keep the target centered. This probelem was later solved in later models."

 

Of course, other websites say that the sidewinder got its name because it seeks out the heat of its prey, like the sidewinder snake. I had a video that explained the reason for the erratic behavior of early sidewinders being due to the gimbal restriction. But, who knows where the heck I put that?

http://64.233.179.104/search?q=cache:RvMG4NOwpb0J:www.fas.org/man/dod-101/sys/missile/aim-9.htm+infrared+seeker+gimbal&hl=en&gl=us&ct=clnk&cd=2

[GGTharos]

From your own source:

 

The Sidewinder improved on this in a number of ways. The first was to replace the "steering" mirror with a system using a mirror that was rotating around a shaft pointed out the front of the missile, with the detector mounted in a fixed location in front of it (not to the mirror)

 

IIRC this is called a 'nutating seeker' ... still lookin' for my file, cross your fingers. I'm starting to wonder if I didn't throw it out when I was done reading it. :(

[Hawg11]

I'm definitely starting to think the limits of the seeker head of the Vikhr are locked in a fixed position. Judging by this picture, I'd say the seeker cannot look dead-ahead. It appears the seeker can only view about 45 degrees off the centerline of the missile. I doubt the seeker for this missile has any gimbals at all; after all, the less moving parts, the cheaper it is to make.

 

 

Top 2 Vikhr's point 45 deg. up, bottom 4 point 45 deg. down.

 

http://www.lockon.ru/img/products/large/204.jpg

 

Of course, that may only be a protective covering that I'm seeing...anyone got any screenies/pictures of the Vikhr in the air?

[GGTharos]

Those are seals. The missile itself has a pointy nose, and no seeker in it. If actually hss a pair of laser receivers in the tail, which see the laser beam emitted from the launching aircraft. It attempts to stay centered in the beam this way - ie. it is a beam-rider.

[Hawg11]

Those are seals. The missile itself has a pointy nose, and no seeker in it. If actualyl ahs a pair of laser receivers in the tail, which see the laser beam emitted from the launching aircraft. It attempts to stay centered in the beam this way - ie. it is a beam-rider.

 

hehe rgr, was just typing that it may only be a cover, when I saw that u posted that :)

[GGTharos]

No problem. Sorry for the typos :)

 

PS: I searched and searched for that paper, but... :(

 

I remembered that I had printed a hard-copy though, so I'll see if I can find that.

[Jason76]

Interesting comments guys...

 

Thanks for the info; there is still tons for me to learn about modern weaponry.

[Force_Feedback]

The Vikhr was designed as a cheap and versataile weapon, hence the one control axis, which is more common in "portable" ATGMs. Also the beam-riding concept ensures maximum jamming resistance and does not trigger laser warning receivers on targeted tanks and aircraft.

The Vikhr also has a proximity fuse, which is switched on when engaging aircraft, don't think that's moddled in lomac now.

[nscode]

Think there's a sepperate version for airborn targets..

[Force_Feedback]

Think there's a sepperate version for airborn targets..

 

Nyet. Same thing is used against high flyers

[nscode]

Here's where i've read it:

 

The Ataka-V family includes several versions, the basic one being the 9M120 with a shaped-charge warhead against armored targets and its improved version being the 9M220. Addition of a second warhead, a demolition warhead, has created the Fugasnaya [High-Explosive] 9M120F. Another version used against airborne targets is the 9A2200 with a rod warhead.

[Force_Feedback]

Here's where i've read it:

 

THe russian book I have says that it had a tandem warhead and a proximity fuse, which detonates the missile if it comes within 5m of the target, although this book refers to the 9A4172 missile. It further states that the missile had a main cumulative fragmentation charge weighing 8kg, to ensure effectiveness against armor and flying objects.

[GGTharos]

... and does not trigger laser warning receivers on targeted tanks and aircraft.

 

THat's incorrect. You're beaming a laser beam at the target ... it takes nothing more than that to make the laser warning receiver to scream at you.

 

The Vikhr also has a proximity fuse, which is switched on when engaging aircraft, don't think that's moddled in lomac now.

 

Not in 1.1 anyway, though the missile does have a fuze, fuzes has ve some limitations that make it look like it doesn't.

[Force_Feedback]

THat's incorrect. You're beaming a laser beam at the target ... it takes nothing more than that to make the laser warning receiver to scream at you.

 

Not in 1.1 anyway, though the missile does have a fuze, fuzes has ve some limitations that make it look like it doesn't.

 

It is said that it doesn't exceed the trigger threshold of western laser receivers.

[GGTharos]

Heh. Said by whom? ;) You got a laser sitting on you for over 2 sec, I'd call that 'exceeding the trigger threshold' ... the illumination doesn't need to be all that powerful.

[D-Scythe]

It is said that it doesn't exceed the trigger threshold of western laser receivers.

 

...and? Don't leave us hanging ;) Tell us how you know it doesn't exceed the threshold of western laser recievers.

[Force_Feedback]

...and? Don't leave us hanging ;) Tell us how you know it doesn't exceed the threshold of western laser recievers.

 

The book "Illustrated guide of Homeland antitankcomplexes" ISBN: 5-17-011744-2 On page 175 it states: "Besides, the power level of the laser beam was determined to be beneath the operation treshold of foreign laser warning systems." That statement in the book has a [2] at the end of the sentence, the [2] refers to: an article from the "Nevskii Bastion" no.1, 1996 "Guided weapon complex <Cobra>" , by A.V. Karpenko.