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Lock-On-Jam with S-75...how does it work?

Posted By: Redcoalition

Lock-On-Jam with S-75...how does it work? - 02/24/11 10:00 PM

I have a question, it's stupid, but still... I need to know the answer.
If i lock a jamming target with the S-75 using the T/T normal guidance mode, the missile will follow the target's elevation and heading?! Assuming that the answer is yes, then why, when I do this, the missile follows the angle of the target and its heading, however, loses signal and fails to explode, even though I'm sure that the target is within range?
I think i still didn't undertood the theoretical concept of the "anti-JAM" guidance. Sry if this question is too dumb frown
PS:. I think i undertood, but still need confirmation. The missile doesn't explode by himself, he needs the command for exploding or desactivating from the battery, is it right?
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/24/11 11:42 PM

I have a question, it's stupid, but still... I need to know the answer.

Its not stupid, we are getting to the advanced stuff again.
smile

If i lock a jamming target with the S-75 using the T/T normal guidance mode, the missile will follow the target's elevation and heading?!

Correct.

Assuming that the answer is yes, then why, when I do this, the missile follows the angle of the target and its heading, however, loses signal and fails to explode, even though I'm sure that the target is within range?

Missile should know when to arm its radio proximity fuse.
This is the crucial point. If it is not armed, than it will fly beside the target, and will not explode.

There is two method in this case.
One is the I87V, when you guess the target range, and the missile will be armed few km before the range bore sight.

The other advanced method is the RAB.OT.VM, where you arm it right after launch.
The catch is that if the enemy is jamming the radio proximity fuse frequency, then they can pop it up well before the target.

This is why on normal method, the radio proximity fuse is armed just 300m before the target.

RAB.OT.VM switch is marked here...
... if you flip it up, missiles will be armed right after launch.


Posted By: Redcoalition

Re: Lock-On-Jam with S-75...how does it work? - 02/24/11 11:57 PM

Thank you, thank you!
Helped alot.
Posted By: vintorez

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 10:41 AM

"Assuming that the answer is yes, then why, when I do this, the missile follows the angle of the target and its heading, however, loses signal and fails to explode, even though I'm sure that the target is within range?"

I think it would by more appropriate to say "the missile does everything it can to follow the angle and heading of the target". That's why evasive maneuvers of the target are another reason. If angle and elevation values change too fast, the T/T method requires missile to make turns beyond its agility level (note that sometimes missile's path with T/T differs the most from the boresight lines when it closes to the predicted by us, clever FCOs, range of the target). That's why T/T is not recommended against fast moving targets.

"The catch is that if the enemy is jamming the radio proximity fuse frequency, then they can pop it up well before the target."

...or give you a more nasty surprise, popping up just after leaving launcher (kill radius 300 m or so? skullhead)
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 11:30 AM

"The catch is that if the enemy is jamming the radio proximity fuse frequency, then they can pop it up well before the target."
...or give you a more nasty surprise, popping up just after leaving launcher (kill radius 300 m or so? skullhead)


No. The RAB.ot.VM means work from clock/time.
After the launch, a clock is started in the missile, and at approx 7km from the launcher, it arms the radio proximity fuse.
Posted By: vintorez

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 11:54 AM

Yeah, it's prudent (sigh of relief) smile
Posted By: Redcoalition

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 02:25 PM

Originally Posted By: vintorez

I think it would by more appropriate to say "the missile does everything it can to follow the angle and heading of the target". That's why evasive maneuvers of the target are another reason. If angle and elevation values change too fast, the T/T method requires missile to make turns beyond its agility level (note that sometimes missile's path with T/T differs the most from the boresight lines when it closes to the predicted by us, clever FCOs, range of the target). That's why T/T is not recommended against fast moving targets.

Thanks, I had understood this fact when the PLCC and Hpasp were discussing about the Over G capability of the mentioned missiles and its consequence in the engagement process. I had found someone to translate the graphics, now it became a good source of research, thank you.

PS:. The nuclear warheaded missiles of S-75M3 were tested on live practice? If yes, they did it on Ashuluk? biggrin
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 04:48 PM

They did it south of the Asuluk firing range.

RA-6 "special" warhead in its transport vehicle.


RA-6 warhead mating with the V-760 missile.


Just press "PUSK" and take cover...
screwy
Posted By: Redcoalition

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 05:13 PM

Thank you very much once again.
Hpasp, is there any pictures or video records of the launch or the explosion in this test?!
Second question about same warhead: The RA-6 was fielded on specific S-75 batteries during normal readiness or they intended to deliver it only in certain situations to specific batteries (eg: During the soviet equivalent of Defcon1 these RA-6 would be delivered to Moscow district sites)? I'm curious about the earlier anti-nuclear soviet defence plans.
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 05:38 PM

The RA-6 was fielded on specific S-75 batteries during normal readiness or they intended to deliver it only in certain situations to specific batteries (eg: During the soviet equivalent of Defcon1 these RA-6 would be delivered to Moscow district sites)?

They were fielded only in the Soviet Union.
There were 3 RA-6 warhead allocated per batteries (against incoming B52 formations) at the No.7A air-conditioned storage building.

I and fellow exFCO's are doubt if the RSNA would survive a 15kt nuclear blast at ~40km.
screwy

I looked for it but didn't find any lamps indicating which emission mode (FKM or MHI) i'm emitting. Is there any or i need to memorize which button i had pressed?!
grunt

Posted By: StartbahnWest

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 06:46 PM

Originally Posted By: Hpasp
The RA-6 was fielded on specific S-75 batteries during normal readiness or they intended to deliver it only in certain situations to specific batteries (eg: During the soviet equivalent of Defcon1 these RA-6 would be delivered to Moscow district sites)?

They were fielded only in the Soviet Union.
There were 3 RA-6 warhead allocated per batteries (against incoming B52 formations) at the No.7A air-conditioned storage building.

I and fellow exFCO's are doubt if the RSNA would survive a 15kt nuclear blast at ~40km.
screwy

I have a nice book "Waffen Enzyklopädie" (the english version has the title "Weapons - An international encyklopedia 5000 B. C. to 2000 A. D."), and it has a nice chapter about the effects of a nuclear detonation. Following effects are important in the first seconds of a detonation: air pressure and his effect on the buildings and the heat wave.
For the heat wave there are 7 categorys:
A - metal evaporates, B - metal melts, C - rubber is melting, D - wood is burning, E - burn of the skin, 3d degree, F - burn of the skin, 2nd degree and G - burn of the skin, first degree.
Effect of the air pressure on the buildings:
0-1 -> total destruction, 1-2 -> massive buildings are destroyed, 2-3 -> smaller objects are destroyed, 3-4 -> high buildings are damaged, 4-5 -> fabrics are destroyed, 5-6 -> dwellings are destroyed, 6-7 -> vehicles fallen, 7-8 brick houses are damaged, 8-9 wooden houses are damaged.
So now the interesting part the radius of each zone depending on how strong the warhead is:
200 kt:
A -> 0 - 1,7 km; B -> 1,4 - 2,5 km; C -> 2,4 - 5 km; D -> 3,7 - 5,8 km; E -> 5,3 - 7,6 km; F -> 6,7 - 10,5 km; G -> 9 - 15,3 km

1 -> <1,3 km; 2 -> <1,6 km; 3 -> <1,7 km; 4 -> <2,2 km; 5 -> <2,8 km; 6 -> <3,5 km; 7 -> <4,5 km; 8 -> <5,4 km 9 -> <9,4 km

There are also radii for a 1 Mt and even a 10 Mt warhead but i think its enough to answer the question could the battery survive an explosion of a small (compared to the mentioned above 200 kt warhead) 15 kt warhead at 40 km distance...
Edit: The overpressure in kPa left and the speed of the air in km/h right:
1: 21000 - 1078; 2: 14000 - 766; 3: 10500 - 611; 4: 7000 - 466; 5: 4900 - 362; 6: 3500 - 257; 7: 2100 - 186; 8: 1400 - 112; 9: 700 - 77
Posted By: Lieste

Re: Lock-On-Jam with S-75...how does it work? - 02/25/11 10:15 PM

Don't forget that one of the effects of a nuclear blast is a pulse of electromagnetic radiation, and the SAM site has several sensitive receivers/amplifiers as part of it's radar equipment.

Almost no risk of blast damage, but without your sensors/illuminators/electronics, that is almost irrelevant?
Posted By: PLCC

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 01:41 AM

I doubt that there would be any damage at all. For a small 15 kt detonation at an altitude of merely 15 km, there would most probably not be a dangerous pulse. The "sensitive" electronics are all vacuum tube based, and thus highly resistant to such effects.

Additionally, the Soviets obviously would not have fielded the warhead if the expense of taking out just one B-52 formation would subsequently eliminate SAM operation in large sectors of the defended territory.


Originally Posted By: Hpasp
I will need to rewrite the missile dynamics...
biggrin


I have read the report. The graph in question refers to the V-601PK variant, which had a reduced booster propellant load in order to decrease the minimum engagement range. As a consequence of the lower initial velocity of the second stage, the range is reduced. According to the report, the maximum acceleration of the baseline V-601P is somewhat greater, at 14 G; those contours do not apply because the V-601P's velocity is significantly larger across the flight envelope. In my opinion, the more interesting data from that report relates to the control system: the amplitude and phase plots of the opened autopilot control loop.

The applicability of the 14 G figure itself to newer models is in doubt. The V-601P/5V27 was introduced in 1964, and modernizations have followed. There is only scattered data on what is likely the original 5V27 among those documents. While the provided technical description books cover do the newer 5V27U, they feature no concrete information. As far as I know, the newest model produced by the Soviet Union was the 5V27D, for which I have found no significant data. There appears to have been a single technical description book posted on a file hosting site, but it is no longer accessible.


I finally analyzed the the graph previously posted of a known 5V27D flight. The result is consistent with the flight time graph, figure 26 (p. 151) of the explanatory note to the rules of firing of the S-125M, but smaller by about 2 seconds. After the switch to composite propellant in the 5V27 from the nitrocellulose/nitroglycerin used in the 5V24 for the sustainer motor, it is doubtful that there remained much additional margin for an upgrade to the energetics. Therefore, the difference is likely the result of reduced trajectory fluctuations of the KDU method, along with error caused by my rough integration.

The point is, while the motor may not have been further upgraded, other components of the 5V27U, 5V27D, etc clearly were. Combined with the suspicion that substantially more than 14 Gs is required to successfully destroy a maneuvering tactical aircraft (as mentioned earlier, the advantage of the missile over the target should be at least a factor of three for a reasonable probability of kill), I conclude that the lateral acceleration capability of these later models was much more than a mere 14 G. The 18 G figure quoted earlier sounds far more reasonable.
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 09:10 AM

Thanks for the translation.
I will not touch the Neva, but I will completely rewrite the Volhov with the data found on page 5, 6, 32
http://narod.ru/disk/21799992000/%D0%BE%...0%203.djvu.html

and page 103
http://narod.ru/disk/2690488001/%D1%81%D...%9C3..djvu.html
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 09:16 AM

Speed characteristics of the V-601P missile against elevation can be found on page 36
(for V-600P on page 39)
http://narod.ru/disk/22604071000/%D0%BE%...D0%9D.djvu.html
Posted By: PLCC

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 09:20 AM

Here is what I was referring to for the S-125:

Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 09:40 AM

Ok, but it is time against range and altitude, Im looking for overload against range and altitude.
Posted By: Redcoalition

Re: Lock-On-Jam with S-75...how does it work? - 02/26/11 03:30 PM

Originally Posted By: Hpasp
grunt


Found it earlier, that's why i edited the question! smile
Anyway, many thanks for the answers about RA-6 warhead!
Posted By: Wolfhound

Re: Lock-On-Jam with S-75...how does it work? - 03/02/11 01:23 PM

Originally Posted By: PLCC
The point is, while the motor may not have been further upgraded, other components of the 5V27U, 5V27D, etc clearly were. Combined with the suspicion that substantially more than 14 Gs is required to successfully destroy a maneuvering tactical aircraft (as mentioned earlier, the advantage of the missile over the target should be at least a factor of three for a reasonable probability of kill), I conclude that the lateral acceleration capability of these later models was much more than a mere 14 G. The 18 G figure quoted earlier sounds far more reasonable.

The AIM-9B was designed to be used against tactical aircraft, yet had a maximum lateral single plane acceleration of 11G.
Posted By: PLCC

Re: Lock-On-Jam with S-75...how does it work? - 03/03/11 02:55 AM

The AIM-9B was designed to be used against non-maneuvering bombers.
Posted By: Wolfhound

Re: Lock-On-Jam with S-75...how does it work? - 03/03/11 04:41 AM

Originally Posted By: PLCC
The AIM-9B was designed to be used against non-maneuvering bombers.

I stand corrected PLCC smile In comparison do you know what sort of target the SA-3 was primarily designed to defeat?
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 03/04/11 10:42 AM

The SA-3B S-125M Neva standard missile (V-601P) has overload capability of 14~2g.
Posted By: Wolfhound

Re: Lock-On-Jam with S-75...how does it work? - 03/05/11 02:03 AM

Originally Posted By: Hpasp
The SA-3B S-125M Neva standard missile (V-601P) has overload capability of 14~2g.

Do you mean an overload capability of 14g to 2g (low speed high alt) or 14.2g?
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 03/05/11 08:26 AM

I mean an overload capability of 14g to 2g depending on several factors.
- missile weight/distance from launcher
- missile speed
- missile altitude
- second stage active/passive state

like this...


14g is at around 7-12km distance, 0-3km altitude
Green line is where the second stage burns out (21.2s), from there the missile decelerates.

Missile speed is depending on flight time, and flight elevation.



This is what the next release of sim will contain thumbsup
Posted By: PLCC

Re: Lock-On-Jam with S-75...how does it work? - 03/05/11 09:13 PM

Are you sure you wish to use data from old, slow missiles?

5V27D, 50 degree elevation:

Posted By: Wolfhound

Re: Lock-On-Jam with S-75...how does it work? - 03/06/11 02:07 AM

Originally Posted By: Hpasp
I mean an overload capability of 14g to 2g depending on several factors.
- missile weight/distance from launcher
- missile speed
- missile altitude
- second stage active/passive state

like this...


14g is at around 7-12km distance, 0-3km altitude
Green line is where the second stage burns out (21.2s), from there the missile decelerates.

Missile speed is depending on flight time, and flight elevation.



This is what the next release of sim will contain thumbsup

Thanks Hpasp, that's great news smile
I really need to learn Russian.
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 03/06/11 03:02 PM

Are you sure you wish to use data from old, slow missiles?
5V27D, 50 degree elevation:


Yes. yep

5V27D (V-601D) become available only after the Cold War.
Before '99, everybody used the V-601P, (-PU, -PD, ...).

I heard rumors, that the 5P73 could handle only 3pcs of V-601D, as those weight is higher.
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 03/07/11 06:47 AM

Guidance method KDU is used in your graph.
Also it can be seen, that the first stage accelerated the missile to lower speed (500m/s compared to 600m/s) due to the heavier second stage, that achieved higher top speed. (1000m/s compared to 900m/s)
wave
Posted By: Hpasp

Re: Lock-On-Jam with S-75...how does it work? - 03/08/11 01:05 PM

I can confirm, that following your proposals, the next version will contain the possibility to select between the following missile types...

- V-755 20DSU or V-759 5Ya23 for the Volhov system.
- V-601P 5V27U or V-601PD 5V27D for the Neva system.

These missiles should perform within 1% of the original firing range data...
thumbsup


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