Home Forums Modern Russian tank shooting, 1992

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  • #159002
    Avatar photoJohn D Salt
    Participant

    In my relentless pursuit of armour penetration information that isn’t pretty much drivel, I have been trying to estimate the velocity decay curves of WW2 Russian guns by working backwards from a very official-looking penetration table and, really, only discovering that drivel inhabits official-looking tables, as well as on-line discussion fora.

    I did, however, using my well-known “trip over something interesting while looking for something else” accidental research method, turn up the following piece from 1992 on questions of tank shooting then apparently occupying the Russians. I thought it was interesting enough to translate in full, as it includes some estimates of kill probabilities for Russian tanks facing M1A1 and M1A2 Abrams, and reflects some of the problems the Russians would have had facing tanks that were clearly rather better than their own. I have fiddled with the format of the tables to make them (I think) more readable. I don’t think it’s worth including translator’s notes, but I could have wished that Sokolov explained more of the assumptions behind the probability-of-winning-a-duel measure. I’m tempted to assume that rate of fire was not properly modelled, as I reckon M1s would almost always fire first and faster when facing Russian tanks. I also reckon the P(hit) assumed for Russian gunnery is wildly over-optimistic; working backwards from the numbers given for P(kill if it) and SSKP, the P(hit) values must be something like:

    1 km    1.5km   2km
    97%	88%	68%
    

    …and on the move, as well. So these numbers are quite possibly drivel, too; but an indication of the way people were thinking at the time.

    All the best,

    John.

    – – – – – – – – – cut here – – – – – – – –

    Approaches to improving the armament of production tanks
    V Ya Sokolov
    Transport Engineering Bulletin No. 2. 1992

    http://btvt.info/5library/vbtt_1992_02_apfsds.htm

    Approaches to ensuring the firepower effectiveness of production tanks by increasing the armour-piercing power of sub-calibre projectiles are considered, and the need is confirmed to improve the fire control system to fire projectiles with characteristics other than those originally specified in the system. It is demonstrated that, in order to improve the capability of the tank, it is necessary to improve its protection as well as its armament system.

    In the context of limiting the number of tanks in accordance with the Treaty on Conventional Forces in Europe, it is important to ensure the required level of the main combat capabilities of the tank: firepower, survivability and mobility, which determine the aggregate potential of combat units. In this connection, attention must be paid to the effectiveness of work carried out in the United States to increase the power of armour-piercing subcalibre projectiles (APFSDS) for the 120-mm smoothbore gun and the levels of protection of the M-1A1, IPM-1A1 and M-1A2 tanks. The penetrating power of the M829A1 APFSDS, adopted for serial production in 1989, is 360mm at an angle of 60° from normal at 3000m, and the improved APFSDS type ХМ829Е2 is 370mm under the same conditions. The level of protection of tanks is characterized by the equivalent resistance of armor, which for the M-1A1 is 500 mm from the M829A1 ammunition, for the M-1A2 – 700 mm from the XM829E2.

    The slowdown in the development of new technical solutions to improve ammunition and protection characteristics, as well as extended periods taken to introduce thermal imaging sighting systems, have led to a lag in technical capability growth for Russian production tanks to the technical level of the M-1A1 tank. To eliminate this lag, it is necessary to speed up the corresponding work, and in conditions of limited resources, it is advisable to establish the sequence of their implementation, depending on the time needed and technological maturity levels.

    From the current position, two areas of such work are possible – modernization of existing models of tanks during their serial production, and the development of a new model. Let’s dwell in more detail on the possibility of implementing the first approach, first by increasing the power of its APFSDS. For this, as you know, it is necessary to increase the relative length of the projectile by reducing the diameter of the core (needing an L/d ratio of ≥25…30, where L is the length of the projectile, and d is the diameter of the core). In addition, it is necessary to improve the aerodynamics (to minimize the loss of speed along the trajectory) and to increase the manufacturability of the projectile design.

    When assessing the power of projectiles (table), the following measures of firepower were used: Pk(h) – conditional probability of destroying a target when hit; SSKP is the total probability of hitting the target, taking into account shooting accuracy; RN is the average (expectation) of the number of rounds needed to destroy one target. The calculations were performed for conditions of firing on the move using the type 1A45 fire control system; ballistic dispersion of projectiles, expressed by the expected angular deviation from the target in the vertical (DV) and in the lateral direction (DL), are equal to DV = DL = 0.20 mrad.

    Armour penetration 	М1А1 tank at (km)	М1А2 tank at (km)	
    at 60° at 2000m (mm)	1	1.5	2	1	1.5	2
    Probability of kill if hit						
    	300		50%	42%	36%	22%	21%	20%
    	330		58%	56%	63%	26%	25%	24%
    	370		60%	60%	59%	54%	49%	42%
    Single shot kill probability						
    	300		49%	37%	25%	21%	18%	14%
    	330		57%	51%	39%	25%	21%	17%
    	370		58%	53%	41%	53%	44%	29%
    Expected rounds per kill						
    	300		2	2.7	4	4.8	5.6	7.2
    	330		1.8	2	2.9	4	4.6	5.9
    	370		1.7	1.9	2.4	1.9	2.3	3.4
    

    It follows from the table that to destroy M-1A1 and M-1A2 tanks at a distance of 1.5-2.0 km at a target-servicing rate of three rounds per target, armour penetration must be at least 370 mm. Such armour penetration can be achieved by increasing the length of the projectile body, which will require laborious and expensive modifications to the autoloader mechanism.

    To improve the effectiveness of firing new ammunition, it is also necessary to refine the fire control system (FCS) of tanks, which will make it possible to take into account the ballistic dependencies of the angle of sight and flight time during firing, and also to enter the vertical and horizontal departure angles for a wide range of ammunition, including APFSDS.

    The solutions adopted in modern FCS using correction inputs do not fully meet the accuracy and operational requirements for the system for the following reasons:

    Large systemic errors when entering corrections for the aiming angle in the form of a constant correction for range (FCS 1A40) or for elevation (FCS 1A33);

    Failure to take into account changes in ballistic characteristics in flight time (1A40, 1A33); newly introduced ammunition is assumed to have the same flight time as the standard ammunition;

    Failure to take into account (due to the absence of an input facility) the departure angle in the horizontal plane (1A40, 1A33);

    Low efficiency of input of information about vertical and horizontal departure angles in FCS 1A40 and 1A33, due to the need to install a collimator, connect a range input device, etc.;

    Insufficient generality of projectile types, aggravated by the fact that the introduction of new types of ammunition requires a radical improvement in methods of accountng for the dependences of aiming angle and flight time on the distance of the lead point, for projectile initial velocity and ballistic coefficient.

    The need to improve the FCS is demonstrated by the fact that insufficient consideration of ballistic characteristics when firing from the halt at a fixed target No. 12 KS-84 with FCS type 1A45 leads to a decrease in the actual firing range: at 1km by 400, at 2km by 1200 m (excluding changes in corrections for deviations from normal firing conditions).

    When defining a set of measures to improve the technical level of a tank and carry out work to improve its basic qualities in the course of mass production, along with increasing firepower, an important role is played by strengthening the tank’s protection. In this regard, it is interesting to compare the possible directions of the development of the main combat capabilities of the tank according to the criterion of the probability of victory in a duel, PV, when Russian tanks equipped with a type 1A45 FCS are shooting against M-1A1 and M-1A2 tanks.

    The values ​​of this criterion are, for different levels of protection of a Russian tank when shooting at 2 km with APFSDS with armour penetration of 300/370 mm at an angle of 60°:

                                        Penetration at 60° vs target
    Protection level 	300mm vs   	370mm vs   	300mm vs   	370mm vs 
    against APFSDS:		М-1А1		М-1А1		М-1А2		М-1А2
    Current Russian 	
    production tank		38%		44%		33%		40%
    М-1А2			44%		52%		35%		48%
    

    Analysis of these data shows: when firing at the M-1A1 tank, the PV indicator increases 1.16 times due to the increase in the power of the ammunition. If, along with firepower, the level of protection of the tank increases, it increases by 1.36 times. When firing at the M-1A2 tank, which has an increased level of protection compared to the M-1A1 tank, the increase in firepower due to the power of the ammunition action is higher (1.21 instead of 1.16 due to the increased level of protection), protection gives an increase of 1.38 times, and the combination of these properties leads to an increase in PV by 1.45 times.

    Taking into account the averaging for both types of tanks in relation to their expected relative quantitative composition (0.78 – M1A1 tanks, 0.22 – M-1A2 tanks) by 1996, the generalized value of PV will be 0.51.

    Conclusions:

    1. To ensure destruction of tanks such as M-1A1, M-1A2 with an average of less than three rounds at a distance of up to 2 km when firing on the move, it is necessary to increase armour penetration of the projectile to 370 mm at 60°, for which the autoloader must be modified so that the upper part of the ammunition with a lengthened APFSDS shot can be placed in it.

    2. To ensure that expected ammunition consumption does not exceed three shots, keeping ballistic dispersion DV = DL ≤ 0.20 mrad, the fire control system should be improved so that it allows effective firing of ammunition with different ballistic characteristics and takes into account type-specific angles of projectile departure.

    3. Along with measures to increase firepower, to increase the tank’s capability it is necessary to increase its protection against a striking projectile, which will allow, when the level of protection corresponding to the M-1A2 tank is reached, an increase in the probability of victory in a duel by an average of 1.38 times.

    #159014
    Avatar photoWhirlwind
    Participant

    Those assumed hit probabilities do pop out a bit!

    One question, is there a typo in the line in the second table: M1A1 at 2km against the kill probability in the 330 line?  I can’t think why it would go up to 63%?

    #159016
    Avatar photoJohn D Salt
    Participant

    One question, is there a typo in the line in the second table: M1A1 at 2km against the kill probability in the 330 line? I can’t think why it would go up to 63%?

    Well spotted. The 63% figure is given in the original. For the sake of guessing the most explicable miskeying I would guess that 53% was more likely.

    There are only two reasons I can think of for p(kill) to increase at longer range, shatter gap and plunging fire, and neither seem likely to apply here.

    Another reminder that drivel inhabits official-looking tables.

    All the best,

    John.

    #159064
    Avatar photoMartinR
    Participant

    Another fascinating piece. Even if the absolute values are rather optimistic, I guess the relative values are roughly OK. The author mainly seems interested in making his point about developing more powerful APFSDS ammo.

     

    "Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

    #159097
    Avatar photoJohn D Salt
    Participant

    Even if the absolute values are rather optimistic, I guess the relative values are roughly OK.

    Yup — a classic analysts’ excuse for offering estimates they know to be wildly optimistic!

    Optimism in p(hit), for both sides, also seems evident in the following 1980 estimates of SSKPs from a 1980 DOAE report (DEFE 48/1076, “Cost-Effectiveness of Chieftain, Challenger and MBT-80”):

    Range (m)	         500	1000	1500	2000	2500	3000	3500
    MBT-80 Mk 2 on T-72	 93%	 89%	 83%	 72%	 58%	 46%	 36%
    125mm on Chieftain	 97%	 92%	 80%	 64%	 51%	 40%	 31%
    

    As a nod in the direction of operational friction, the paper report mentions that 28% of rounds are assumed to be fired against dead targets, based on the recent experience of Exercise “Chinese Eye”.

    All the best,

    John.

    #159109
    Avatar photoMartinR
    Participant

    LOL. Off the top of my head I can’t recall the combat degradation factor for AFV crews from ‘The Stress of Battle’, but shouldn’t all these numbers be divided by at least seven to get the actual p(hit) in combat conditions?

    "Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

    #159450
    Avatar photoNick Riggs
    Participant

    Rowland and Speight (2007) Surveying the Spectrum of Human Behaviour in Front Line, Military Operations Research, V12 N4 2007, in Table 1 on p. 48 shows a degradation factor of 1/6 for main battle tanks (as per MGs). I couldn’t see this figure in The Stress of Battle though.

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