That_Baka

It is time to explain The Aglockalypse.
 


This is the handgun that killed handgun design in the West.  Nobody has had any new ideas worth mentioning on the mechanical design of service handguns since this design came out.  Almost every major arms manufacturer in the West makes what is materially a Glock clone; albeit with a few small embellishments and their own logo stamped on the side.
 
What Makes a Glock a Glock?
 
Almost every mechanical contrivance in small arms design was invented about one hundred years ago by some Austro-Hungarian noble you've never heard of or by John Moses Browning.  It's about 50/50.  Most of small arms design these days consists of applying new materials and manufacturing techniques to old ideas (which may have been unworkable at the time), or by taking a lot of old ideas from different sources and mixing them together in some way that's complimentary.  The Glock pistol design is no exception; the ideas were not novel, but putting them all together proved an absolutely world-beating combination.
 
1)  Polymer Frame
 

An H&K VP-70, the first production polymer-framed pistol.
 
Polymer-framed pistols were not an original idea, but at the debut of the Glock 17 they were still a fairly new idea.  Glock proved the concept to be mature, and it provided the Glock with a huge advantage over the competition.

Traditional metal-framed pistols are made by taking a hunk of metal, either a casting, billet or forging, and cutting away everything that isn't pistol-shaped:


 
This translates to a lot of machine time and a lot of expensive alloys that end up as shavings on the floor.  The frame of the Glock was much faster and cheaper to make.  Some metal inserts were put into an injection mold (which admittedly is an expensive device, but you pay for it once), and then hot, liquid plastic was squirted into this cavity to form the frame.  The entire process takes less than a minute.  Cost-wise there is no way for a metal-framed pistol to compete with a polymer-framed one, apples to apples.  For very large contracts the math tilts even further in favor of injection molding, since one-time capital costs are a large percentage of injection molding costs while ongoing costs are smaller, while ongoing costs for machining stay largely the same.  Gaston Glock was very aggressive about pursuing large contracts (notably the NYPD, which was an early coup), which helped him best use this advantage.
 
2)  The Glock locking system
 

 
Glocks use a linkless Browning tilting-barrel short recoil system and lock the slide to the barrel via a large rectangular lug machined into the barrel that fits into the ejection port.  Glocks were the second major pistol design to combine these two concepts, the first being the SiG P220 series.
Ejection port of a Webley automatic pistol, showing the square breech section of the barrel locked to the slide via the ejection port.  The barrel translates diagonally.
 

Cross section of a Browning hi-power.  This was the first mass-produced pistol to use the linkless short recoil system.  The barrel locks to the slide via a series of rings in the barrel that tilt into corresponding grooves in the slide.
 

SiG P220

This operating system is robust and reliable, and fairly easy to manufacture.  It has a few theoretical flaws, such as the barrel being slightly off-angle during the extraction of the spent case, the pivot sitting below the barrel and thereby raising the bore axis, and the necessary clearances for the movement of the barrel degrading accuracy.  In practice these objections are immaterial.  Glocks are absurdly reliable, have a low enough bore axis and only a unusually skilled shooters would notice the mechanical contributions of the precision of the pistol over their own wobbling aim.
 
3)  The Glock Fire Control System
 

 
The Glock fire control group is an elegant combination of several ideas.  Again, most of the ideas in the Glock fire control group had antecedents, but their combination and execution in the Glock was very clever.  The trigger transfer bar is a complex shape, but it is stamped from sheet metal and so quite cheap to produce.  It also combines several functions into a single piece, including enough safeties that Glocks are reasonably safe to carry even though they lack an external safety.
 
The complete lack of a machined metal hammer, and the clever trigger dingus-lever were also cost savings over traditional pistol design.
 
There are several other incidental design features of the Glock pistol, but these three are in my opinion the ones that allowed it to gobble up market share because they economized manufacture.  They are also the three features that the overwhelming majority of Western pistols designed since the Early '80s copy unashamedly.
 
Victims of the Aglockalypse
 
When Gaston Glock first entered his creation in the Austrian Army pistol competition, nobody in arms design had heard of the guy.  Longstanding Austrian arms company Steyr was quite confident that their own GB pistol would win the competition.
 

This is basically the pistol equivalent of the couple making out in the back of a convertible at night in a horror movie.  It is remembered only as the first in a long list of casualties.
 
Instead, not only was the Steyr GB to lose the competition, but it would fade from the marketplace without making much of an impression anywhere.  This is a shame, in my opinion, because the Steyr GB has a few good ideas that deserve a second look, such as the two-position-feed magazines (seen otherwise only in rifles, SMGs and Russian pistol designs), and the truckbed-liner crinkle finish.  The design also has some good features for economy of production and excellent mechanical precision, but really, on the whole, it's completely inferior to the Glock.  These pistols have a really poor reputation for being unreliable and wearing out quickly, and while Steyr fans will claim this is in large part due to inferior license-produced versions from the United States, nobody argues that even the Steyr-made GBs have anything on the nearly bomb-proof Glock.  Also, they're enormous.
 
As far as the Glock was concerned, the Steyr GB was just the first blood.  It wasn't enough to best a local competitor; the Glock would obsolete an entire generation of automatic pistol designs.
 
In neighboring Germany, Heckler and Koch's flagship pistol offering was the P7.  The P7 has many admirable features.  Like the Steyr GB it has a fixed barrel and excellent mechanical precision.  It is also very slim and has an extremely low bore axis.  It also has the most hideously complicated fire control system ever seen in a pistol that isn't a revolver:
 

 
A pistol like the P7 could simply never be made cost-competitive with the Glock, much less by a company like HK which usually errs on the side of high performance rather than low cost.
 
Walther, the other big German small arms manufacturer, was busy making the P5:
 

 
No, the picture isn't reversed.  The ejection port is indeed on the left side of the P5, which is because the P5 is nothing more than a slightly re-worked P38 of World War Two vintage.  The frame is aluminum, the barrel is shorter and the fire control group has some detail improvements, but it's otherwise the same, right down to the dubious rotating-block locking system.  It didn't even have a double-column magazine.  Just another outdated design for the Glock to drop-kick into the dustbin of history.
 
Longtime Belgian designer FNH was pushing the Browning BDA, a pistol so boring that I can barely write about it while remaining awake.
 

 
This is basically a Browning hi-power with a double action trigger somehow shoehorned in.  Given how the Browning hi-power trigger works, this is not exactly a straightforward conversion, and this would invite curiousity were it not for the fact that this pistol carries with it a highly stiffling aura of impenetrable boringness.  I seriously cannot bring myself to care.
 
Across the Atlantic, in gun-happy America the Glock would face stiff competition from hardened, skillful American firms that had more to offer than face-lifted wartime designs and botique gas-delayed guns.  The rugged American outlook on law enforcement provided a stiffly competitive market for quality peace officers' weapons.  
 
Haha, I kid.  They were just as complacent and mediocre as everyone else.
 

 
Sturm Ruger Co, one of only two publicly traded firearms manufacturers in the US, released their P-series of pistols in the mid eighties.  It seems a little uncharitable to list these chunky pistols as victims of Glock superiority, since they sold in decent numbers and aren't terrible.  But victims they were; the design was simply outdated.

The strangest feature of the P-series pistols is that the older designs in the family use a swinging link to cam the barrel in and out of engagement with the slide.  While the swinging cam arrangement works well enough, and several fine weapons use it (e.g. 1911, Tokarev), with modern materials and manufacturing tolerances the linkless system is simply better because it doesn't produce the grinding movement caused by the short radius of the link swinging radius, and because it has fewer parts.
 
The P series was also reasonably cost-competitive because most of the parts are cast before machining to final dimensions.  Sturm Ruger has exceptional expertise in firearms castings, which has long given them the edge in pricing.  Castings can be made very closely to the final shapes required, which saves a lot of machining time.  However, this gives many of their designs a bloated, water-retaining look.
 

 
The other publicly traded firm, Smith and Wesson, was doing reasonably well with a whole family of automatic pistols that I absolutely do not care about.  They have names that end in "9", have generally Browning-ish insides, and the single stacks look pretty and elegant.  There are also some double stack variants, and some are in stainless.  Something something unbuttoned pastel shirts, designer Italian pants and cocaine.  Oh look, there goes my mind, wandering again because these pistols are BORING, MEDIOCRE AND I HAVE MORE IMPORTANT THINGS TO CARE ABOUT.
 

 
OH LOOK IT'S ANOTHER PRE-GLOCK SINGLE STACK METAL FRAMED PISTOL.  This time it's from Colt.  It is a well-documented fact that Colt's senior management spent the entire 1980's doing nothing but licking their own genitals like cats.  I don't even know what this pistol is called.  Do you know what it's called?  Do you care?  Do you think Colt's management cared?  Of course not.  So let's make up a name.  We'll call it... the Colt Elantra.
 

 
This Colt pistol is more interesting, and has an operatic history.  Unfortunately, that opera is Wagner's Ring Cycle.  Nobody did anything that made sense, and by the end there was a fat lady singing and then everything burned to the ground.
 
The pistol was originally designed by Reed Knight and Eugene Stoner, who were by that time already living legends for designing the combat robots that crushed the communist menace decisively at the Battle of Arrakis.  The design was mechanically fascinating, featuring an unusual rotating barrel, roller-bearing supported striker fire control group, polymer frame with screw-on grips, and an unusual, but very appealing slide stop design.
 
Alas, Colt completely screwed up the design by making it too big, making the trigger pull too long and too heavy, and by making it not work.  Even without the stiff competition from Glock, the design would have been an ignominious failure.
 
All of the above designs, though in some cases initially successful, would face dwindling market share against the cheaper-to produce Glocks.  Their respective firms sat down and quickly came to the conclusion that they were not as clever as Gaston Glock, but that was OK since he had done the clever for them.
 
Saint Gaston Converts the Industry to Glocktholicism
 

 
The first of the Glock clones to hit the market, the S&W Sigma is so similar to the Glock that some of the parts will interchange:


 
This resulted in some drama, hasty design changes and a settlement payment for an undisclosed amount.
 
Next came the Walther P99:
 

 
This pistol introduced the interchangeable backstrap, which was generally considered a good idea.  It also introduced several option trigger modules, including a DA/SA version with a decocker button on top of the slide.  This is bid'ah, and heresy against the Glockspel.  The great genius of the Glock is that it's simpler and cheaper to produce than competing designs.  One cannot successfully outcompete the Glock by taking a Glock and adding a bunch of extra shit to it.  Then you just have a more expensive Glock, which, ipso facto, will not outcompete an Orthodox Glock.
 

 
HK was, until recently, one of the last holdouts of Albigensianism hammer-fired handguns, being unable for some time to bring themselves to make an unabashed Glock clone.  However, their USP series is, compared to their previous offerings, quite Glocky.  They have switched to the Browning short-recoil, linkless tilting barrel design with a barrel that locks to the slide through the ejection port.
 
By 2014, however, HK had entered into full Glockmmunion, and introduced the VP9; a striker-fired, polymer framed pistol:
 

 
FNH of Belgium initially responded with the FN Forty-Nine, which is like a Glock but with a DAO trigger:
 

 
However, they swiftly recanted of their error and introduced the FNP, FNX and finally the FNS, an all-but-Orthodox Glock clone:
 

 
Steyr introduced the M9 series of pistols, which were actually designed by a former Glock employee!  These are basically Glocks, but slanted, with weird sights and that say "Steyr" on the side instead of "Glock."


 
 
In 2007, Ruger was converted and introduced the SR-9:


 
In 2005, S&W made a slightly more refined clone called the M&P:


 
There are several versions now, including some for blasphemers that have external safeties.
 
Colt has yet to introduce a Glock clone; their strategy regarding this portion of the handgun market remains enigmatic.
 

 
 
Survivors
 
For various reasons, a few metal-framed designs have survived and remain commercially competitive.  But there is reason to think that their days are numbered.
 

 
The Beretta M92 series is mechanically rather similar to the Walther P-39, except it has a double stack magazine.  The widespread adoption of this essentially sound, but uninspired design, by many militaries not the least of which is the US Army, has bought the design staying power.  However, the recent announcement that Beretta, too, has discovered how to stencil their own name on to the side of a Glock shows that they haven't come up with anything better either.
 

 
The CZ-75 design continues on as well, in no small part because producing a CZ-75 clone is a right of passage in Turkey that all adolescents must pass in order to be recognized as men.
 

 
Turkish CZ-75 clones are so common at firearms trade shows that they are often used for paperweights and juggling.  When there is heavy snow it is common to keep a bucket of Turkish CZ-75 clones handy to pour onto icy patches to get better traction for a stuck vehicle.
 
But the latest offering from CZ proper, the CZ P-09 is beginning to look a lot like Glock-mas:


 
Polymer frame, barrel that locks into the ejection port...  It keeps the distinctive CZ-75 slide-inside-frame and fire control group, but it's more like a Glock than a CZ-75 is.  The trendline is unmistakable.
 
There are a few other hold-outs, but by and large the firearms industry has found Glock's recipe to be compelling.  To be cost-competitive, new designs copy these innovations to a greater, rather than a lesser degree.  This has meant a stultifying lack of creativity amongst pistol manufacturers, as more and more of them decide that their best bet is to copy a thirty five year old design.

https://m.weibo.cn/status/4314232545708008 some new pics on NGCV OMFV's MET-D, for example:



and also and another render of GCV:

this picture comes to mind:

 
 
 
 
...
Comparing that Bradley drawing with one of the original Bradley from All Vollunteer 1980-07 https://i.imgur.com/WykRCXe.jpg  (most detailed picture of soldiers in Bradley i've got so far)

Those 6 dismounts got some very generous 202-203 cm of space - that is 67,5 cm (26,5 inches) per person, for sholder or forearm-forearm breadth, which is obviously increases a lot (compared to person in summer clothes or nude) when person is carrying a lot of gear of wearing winter clothes
(which no one seems to be bothered about in 1960s or even early 1980s, so IIRC Bradley was designed with something like 56 cm/22 inches in mind - and when in 1984 they measured 95th percentile soldier in uniform for extreme cold weather ("Anthropometry of the Clothed US Army Ground Troop and Combat Vehicle Crewmen"), in turned out that he needs 62 cm/24.5 inches)

 

Great Kharkovite godlike tanks

Spike LR is much better. Fire & observe mode makes all the difference. Basically when firing Javelin you have to see the target to lock on(that also endangers operator of enemy fire, where in case of Spike you can hide safely behind a hill and engage targets BLoS)  which limits the effective range to about 800-1500m(typical LoS in eastern Europe) and after you fire you can't deliberately miss the target so there is a high chance of destroying own vehicles. Can you tell a difference between T-72B3 and PT-91 at a distance of 1-1.5km? Include bad weather conditions which would radically decrease visibility. On the other hand you can fire Spike manually and make sure you will hit enemy vehicle, not yours or redirect missile into more important target you have just detected. You don't have to see the target before you fire and you can make use of the full range of Spike. That's my short take on this. I'm sure that @Militarysta can elaborate more on this.

That's fine.
 
I mean, I am curious but this is a public forum and you may have NDAs etc to think about in addition to not wanting to talk about your former employer.

Did you know that not only was the AK copied from the Stg, but the Mosin is actually just a Mauser?

The identification system of people reading the blog Maxim Rudolfovich  Popenker.

T-80 - The Best tank ever made by USSR.
NOT BY YOU, Kharkovites!
 

 
    After everybody understood that Kharkovites can't build a tank that work well enough for the Last War of the Humanity, the Leningrad designers started to work on their view of a battle tank that can actually fight and win. They saw a main problem with T-64 - it was slow, too slow to do the job. What job you may ask? To disperse capitalism particles in the air, of course!
 
   According to scientific work of the professor Ivan Rasputin Drinkovodkavich the air of the capitalist countries were full of capitalism particles, which would resist incursion of the socialists tanks by creating a strong resistance force and they will block any attempts to build communism in this area, as people will breathe this capitalism-soaked air and this would infect their minds by ideas of free markets and useless things that they usually sell. In order to combat this, a fast-moving tank was needed, that could displace air so fast, that particles of capitalism would be ejected from it and a path for cammunism particles would be open.
 
   LKZ engineers understood that, and were working hard to build such vehicle, that could destroy westerners mercenary armies, blow away capitalism-infected air and fill it with Particles of Communism. Kirov factory workers also understood that the only way to finally kill Kharkovite abomination was to sabotage it by creating their new tank from the T-64 tractor. And the work began, until in 1976 their first itteration of their new Best tank was adopted by Soviet army!
 
 
T-80 (Object 219) - the saboteur, destroyer of the T-64
 

 
 
 
 
 
 
The T-80B (Object 219R) - toppling the T-64 Czar!
(yes, straight to the T-80B, without making T-80A, remember that, Kharkovites)
 
   It is a time to hit Kharkovites right in their fat belly! Their patrons did not noticed how Leningrad managed to grow a new tank just under their noses! Only Kirov factory knows how to make Best tanks, and not those Kharkovites, who want to sell Socialist achievments of USSR to those soulless Westerners. Leningrad will support the Fatherland with their tanks, superior to those untrustworthy Kharkovites crude creations! And who the hell put 40 tons tank on such puny rollers anyway?!
 


    
 
 
 
 
The T-80BV (Object 219RV) - if you kick it, it explode you!
A Hedgehog with explosive needles, try that Reagan!
 

 
   Kirov factory knows how to defeat enemy anti-tank weapons that try to explode Socialism-spreading machines of Brezhnev - explode them before they can explode you! Strap Kontakt-1 ERA everywhere and laugh at those puny westerners, freaked out by a tank that kick their shells back at them!
        The T-80U (Object 219AS) - Ultimate Soviet Guards Battle Tank to deliver free healthcare to your country!        T-80U. It is easy to spot and hard to confuse with anything Kharkovites made, before they created their Kharkovite-80UD, an attempt to undermine BEST SOVIET TANK. YOU KHARKOVITES HAVE NOTHING SACRED!  
    The T-80UK (Object 630A) - a battle tank to be driven by Stalin. Personally. Or other Great Leader of Communism.      The T-80U was so good that Kirov factory received a special order to build a commander version of T-80U to be driven by Great Leaders of Communism personally! This is why T-80UK was created - made out of pure hatred to discont shops and unending stream of wordspuke out of capitalist oppressors heads about how workers are free in their system of exploiting human weaknesses!             The Kharkovite-80UD (Object - we will steal country money just to put our crazy diesel engine into T-80U to ruin it - 478B), a terrible abomination and violation of spirit of true Workers and Peasants ideals by untrustworthy Kharkovites to undermine T-80U achivements, but by this they admit that their T-64 tractor was inferior to Glorious Kirov factory creation, showing how much superior was a concept behind T-80, a true way of creating tanks that Kharkovites would never understand and because they don't understand it they just copied the Great tank of Soviet Guards Armies. Kharkovites can't understand a concept of creating a tank which have everything behind and in it calculated to achive superior perfomance on battlefield against hordes of NATO invaders and not just to wave a pamflets with many paragraphs describing their unique inventions that they added to the tank without thinking about actual perfomances because Kharkovite is trying to sell his tank for personal profit, like decadent westerner, while only Kirov factory think about winning the war with imperialists.   Kharkovite-80UD      

On November 27, 1984, the MBT T-80U tank was officially accepted for service in Soviet army by order № 1184-301 of Central committee of Communist party of USSR and council of ministers.

http://btvt.info/1inservice/t-80u.htm
 
Also this day by the order № №П83-300сс of Central committee of Communist party of USSR and council of ministers T-72B was officially accepted for service in Soviet army.

http://btvt.info/1inservice/t-72B.htm

I was talking about Object 640/Black Eagle turret. It does have a big turret bustle.

Object 490 had turret bustle mounted autoloader, with additional rounds mounted between engine and crew compartment. Both ammoracks were protected/separated from the crew and had blow out panels. Object 640 is not a new designs, it is just attempt to mix T-80 with some of ideas that were used on Object 490.
 

 
   This layout have problems. Having big ass turret bustle is not going to increase overall survivability of tank under fire. It increases side projection and frontal projection in 60 degr arc of a tank in worst place - area higher above the ground, where statistically more hits are happening. Placing ammo in the hull is preferable. 
   Also increasig size of turret isn't good idea for vehicles fighting in urban conditions. They already have long gun barrels to worry about, but gunner can at least see what is happening near muzzle end of guns (usually), unlike turret bustle. 

I finally got around to doing a review of the Acquisition Chapter. Apologies to @N-L-M for the delay, and apologies in advance for the length.
 
This topic comes at perhaps an opportune time given a previous conversation with @Sturgeon regarding the Survivability/Lethality Onion.
 
In this model of lethality, a target must be
First, Seen
Once Seen, Acquired
Once Acquired, Hit
Once Hit, Penetrated
Once Penetrated, Destroyed
 
With survivability obviously working in reverse. This model has proven quite robust and is extremely popular amongst those studying weapon systems and their survivability. Its terms are generally self explanatory, though it's worth clarifying the first two. Seeing refers to the perception of any given object via some form of sensor. Acquisition, then, refers to processing the perceived object *as a target*, by some form of identification or feature recognition.
 
That pretentiousness aside, Driels in this chapter will address both topics; the US Joint Munitions Effectiveness Manual (JMEM) considers them in three parts: Target Detection, Target Recognition, and Target Identification under the titular Target Acquisition model. Detection under JMEM’s model correlates most closely with “See” under the Onion, with the remaining two falling under Acquiring the target.
 
Driels begins by outlining several historical physiological and psychological models for Target Detection, before describing the work by Johnson which is at the core of the US Army’s Acquire model. Terrain, run-in effects, and conversion of range to probability of launch are accounted for, and the factors are combined with the Acquire model to describe the JMEM’s Target Acquisition model.
 
Unlike the prior chapter, this chapter is much more explicitly focused on Air-to-Surface weaponeering. While the physiological and sensor models will obviously hold true for a variety of detectors, they are used here exclusively to create a model for the range and probability at which an aircraft will detect some ground target. Terrain masking is equally applicable to cases beyond that of Air-to-Surface, but such things as run-in effects and the minimum time taken to bring an aircraft to a required heading are limited in their application.
 
Published in 1970, the JMEM Air-to-Surface Target Acquisition Manual divides the acquisition process into the aforementioned three steps of detection, recognition, and identification. Their exact definitions have been included here to preserve the granularity.
 
Blackwell’s research during WW2 began with experiments into the contrast values required to just discriminate circles projected on a screen. Importantly, target size in Blackwell's model is angular in a fashion evident to anyone familiar with MOA.  Beginning with a definition of contrast as
 
C = abs val of (Luminance of Stimulus - Luminance of Background)/(Luminance of Background)
 
And of relative contrast as

Cr = actual target contrast / threshold contrast

This definition becomes clear when one examines the situation where Cr = 1, wherein threshold conditions apply and detection probability is 50%. A table of threshold contrast values has been included here, followed by detection probability as a function of the relative contrast.

Practically speaking, to predict detection with this model would require calculating the angular size of the target, then calculating the actual contrast of the target, looking up the threshold contrast, calculating the relative value, and finally determining the probability of detection with the graph. Evidently a complex and lengthy process, these limitations motivated the creation of further detection models.

Overington’s model seeks to correlate the target size and target contrast to the point at which the target is just detectable. This begins with the assumption that the target generates a stimulus between two adjacent retinal receptors between which the boundary of the target and background is located, the magnitude of which will obviously depend on the  magnitude of the contrast. Through a complex series of equations that do not bear reiterating, a relationship is drawn between

.163 * Contrast = K1 * nReceptors + δ

Where K1 is some constant and δ is the minimum stimulus the brain can detect. From this equation, a threshold contrast value can later be obtained. A great deal of care is paid to the amount of receptors which will be stimulated - the minimum even when seeing very small objects (eg stars) is cited as nine.To account for this, a value of

nReceptors = 9.9[(height + width)^2 + .83]^.5 is derived, where height and width of the object are in mrads.
 
Overington then solves K1 and δ experimentally; they depend on the retinal luminance, which is itself dependent on the scene luminance and the pupil diameter. These equations are not directly solved, and the reader will have to content themselves with the relation of

K1 = 15.4 Retinal Luminance-.5 + .48
And
δ = .00125 Retinal Luminance -.5 + .0004

With Retinal Luminance equal to pi*pupil diameter squared * scene luminance * 1/4

We can obviously now simplify our earlier equation into

Contrast Threshold = (K1 * nReceptors + δ)/.163

Which is in good agreement with the Blackwell model from earlier. It would later be discovered, however, that these models under-predicted the threshold contrast luminescence. Testing conducted by Johnson in the 1950s wherein observers viewed the side of an M48 (a tank not know for it’s small size, as N-L-M will doubtless attest) showed that the threshold value was higher by around a factor of three compared to the Blackwell and Overington models.
 
My only brief complaint with this section is that it would benefit from a lengthier comparison between the predicted values and the empirical values for threshold contrast. The history and physiology is interesting, of course, if somewhat dry if all we are given is a simple “it does not work by this factor”.
 
Johnson’s Frequency-Domain Experiments grew out of these simple “detection” tests, beginning with the fact that mere detection is not sufficient for many military tasks, and that neither a threshold data nor model existed for the tasks of recognition or identification. Initial experiments showed that a nonlinear scaling existed of contrast required with range, which led Johnson to model targets in a frequency rather than spatial domain, best explained visually here.

Each pair of black and white (practically, gray and dark gray) lines is a cycle, and the cycles per milliradian is the cycle frequency. The equivalence between a cycle frequency and a target is constructed as follows.

1. A small image of a military target is projected onto a black screen.
2. An observer is rolled into a position where he can just detect that there is an object on the screen.
3. The image is replaced with a rectangle made of very high cycle frequency bars. The frequency is reduced until the observer can just determine the number of bars.
4. The rectangle is replaced by the image, and the observer is wheeled forward until he just recognizes it. Step 3 is repeated.
5. Step 4 then 3 are repeated with the observer having to identify the target.
 
The procedure's results have been included here.
 
This is a strikingly robust and useful model, and has proven sound even when applied to a number of passive sensors such as FLIRs, TVs, and image intensifiers. With it, we can predict acquisition ability of a sensor by measuring its ability to resolve contrast modulated bar patterns. In this passage, Driels discusses an extremely fascinating way of looking at sensors, in a method that’s surprisingly easy to follow given his early work in the chapter. The model seems so simple and robust that one questions why the earlier models are even included, as the Acquire Model to soon be discussed uses Johnson’s work rather than the earlier physiological models.

The US Army’s Acquire Model makes use of Johnson’s Frequency-Domain work, while accounting for significantly more factors. The model begins by calculating the critical dimension (sqrt of the presented area) in mrads, and then selecting an intrinsic contrast value based on the illumination, background, detector, and filters. The attenuation due to atmospheric factors is also taken into account, though the JMEM model only accounts of distance and meteorological factors. Using these factors, the apparent contrast at the sensor is calculated, with

Apparent Contrast = Intrinsic Contrast * Sky to Ground Luminance * e(-3.91 * Range Kilometers / VIS)

VIS represents the atmospheric visibility, and is defined as the range at which contrast is diminished to 2% of Intrinsic Contrast.

The sensor in question is then analyzed using Johnson’s method described earlier. A common measurement standard is a four-bar pattern which can be of varying frequency - ie, the bars can be very few or very many milliradians wide. For a given frequency, the illumination through the sensor is increased from zero until the bars are just able to be distinguished, and this value of contrast is paired with the frequency to construct a Minimum Resolvable Contrast curve. A particular value of frequency for a given apparent contrast on this curve is a Spatial Frequency, yielding

N cycles resolved = SF * critical dimension / Range

Acquire then features a probability for some task (either Detection, Recognition, or Identification) as a function of the ratio between the number of cycles resolved and the number required for a 50% chance of that task being accomplished, included here.
 
This is a very powerful result, and is again presented quite cleanly and clearly. I appreciate these two passages a great deal more than the earlier parts, especially since they seem most easily applicable to things outside the A2S realm.
 
Flight profile accounts for the fact that an aircraft does not always approach the target directly down the line of sight, and that several actions must occur for a successful attack even after the target is detected. The aircraft must decide to attack, must roll into and then execute a turn before exiting the turn and operating the weapon system - respectively XD, XRI, XRO, XOP, and RMIN in the diagram here. These will combine with the beginning kinematics and geometry - the turn radius of the aircraft r and nose angle ⍺ - to produce the following RRQ equation.

RRQ = (A cos ⍺ + r sin ⍺) +- Sqrt[ (A cos ⍺ + r sin ⍺ )^2 - (A^2 - B^2)]
 
This minimum range to maneuver and launch will be included further along in the model in addition to the maximum range for detection. An omission which may be deliberate is the possibility to reverse engineer a target approach to maximize the possibility of detecting the target in time to launch a weapon. 
 
Searching refers to the process of moving the sensor’s field of view, the solid angle which it can actually “see”, over the entirety of the solid angle the sensor is capable of moving, referred to as the field of regard. Driels places this towards the end of the chapter, but it appears best suited to address earlier. The US Army’s Acquire model expresses the probability of detection as
P = P1 x P2, where P1 is some time-independent probability of detecting the target, and P2 the conditional probability for some amount of time, best explained below.
 
Terrain has the effect of blocking almost all sensors used by aircraft, with the particular quandary that terrain can vary quite rapidly and unpredictably. (Something anyone attempting to learn land navigation can attest to.) Driels constructs a workable model for the angle at which an aircraft’s sensors are unmasked as follows - for a given “type” of terrain, place an observer at some random point. The observer measures the angle to the highest terrain feature along a given bearing, which is the unmask angle. This repeats this for the entire circle, producing a cumulative probability distribution of the unmask angles, and the process may be repeated for a variety of terrain types to any desired level of granularity.

The JMEM target acquisition model covers flat farmland, smooth desert, rolling farmland w/ close forests, rolling desert, flat farmland with close forests, gently rolling hills, rough desert, and sharply rolling hills with trees, though it should be evident that any particular terrain type could be easily calculated. The omission of any form of urban terrain is puzzling, however, and the question of which existing terrain to model it with is thought provoking. Perhaps sharply rolling hills with trees? That this 2004 book does not cover the acquisition of targets in urban terrain is no great discredit, as it has likely been accounted for in more recent versions of the JMEM acquisition model, but it certainly merits further discussion moving forward to a doubtless more urbanized battlefield.
 
There are now models in hand for the two major limits on range of detection, terrain and visibility, and from this Driels proceeds to construct a conversion between range and the probability of detection and launch.
 
This equation, and the cumulative probability that one can derive from it, accounts for not only the distance the aircraft must close to before detecting the target, but also the time taken to search the volume available to the sensor suite and the minimum time/distance required to maneuver the aircraft to launch position. The constant K accounts for the skill level of the pilot, Pmax is assumed to be 1, R is the smaller of the unmask range or the visibility detection range established earlier, RRQ is the minimum range to maneuver and drop. A series of calculations have been performed in the chart here - these seem to be far lower than occurs in reality, potentially due to the choice in parameters.  
 
Driels then details the usage of the JMEM Target Acquisition Model, a screen of which is included here. (Note that PL is significantly higher than his table earlier.) Inputs to the model can be taken from the Joint Air-to-Surface Weaponeering System (JAWS), as well as additional information regarding the target, vision conditions, weapon trajectory, and launcher kinematics - the latter two obviously determining RRQ.
 
In Summary, the chapter examines physiological models of detection by Blackwell and Johnson, addresses their implementation in the US Army’s Acquire model, and then details the Joint Munitions Effectiveness Manual’s use of Acquire and the additional information its model includes. This chapter is interesting and offers a great deal of unexploited potential - the models are all extremely fascinating, and I can easily imagine their direct applicability towards S2S or passive A2A detection. Crucially, however, the acquisition models all appear to completely negate *active* sensors, possibly for reasons of confidentiality. Still, the fundamentals behind the two-way radar equation aren’t that complex, and could easily be slotted into the existing maximum range of visibility parameter. Beyond that, it is an interesting chapter, and one of the most insightful in the book.

I think I'm done with the book for now. I may do some simulation of infantry fires by plagiarizing Driels' direct fire chapter, but that is a tale for another day.

Kedr after some crafty hands work

 

According to different German authors (Rolf Hilmes, W. Spielberger, Frank Lobitz) the base armor used on the last batches of the Leopard 2A4 and on the Leopard 2A5 is based on "D" technology. The original armor package for the Leopard 2 (in "B" technology) remained in production until the 96th vehicle of the sixth production batch; starting with the 97th vehicle of the sixth batch, the new armor kit in "C" technology was used. The original Leopard 2A5 prototype (the KVT) was based on a hull made in 1987 as part of the fifth production batch, hence it was  made with the original base armor package, only the add-on parts made use of newer technology.

 
Beginning in January 1991, the tanks of the eight production batch with new armor in "D" technology were manufactured. These tanks were manufactured at the after the late Leopard 2A5 prototypes (TVM 1&2 Max., IVT) were manufactured, for which the new generation of armor has been developed ("D" technology), hence they used this type of base armor. The Leopard 2A5 KVT was send to Sweden, because the newer Leopard 2A5 prototypes were still being tested in Germany, this is the reason for the "German model" using inferior armor compared to the configuration ordered by Sweden (which apparently used "D" technology base armor + add-on parts). The Leopard 2A4 tanks with "D" technology can be identified by the side skirts - they are identical to the ones used on the later versions including the Leopard 2A5, 2A6 and 2A7.
 

(Leopard 2A4 with "D" type armor)
 
The production model of the Leopard 2A5 tanks for the German army was created by mating Leopard 2A4 hulls from the last production batches (with armor in "C" or "D" technology) with turrets from the earliest production batches. The old turrets are used, because they require extensive rework during which the base armor is replaced with new modules in "D" technology. This actually means that some Leopard 2A5 hulls might be better protected than other. There are no add-on armor modules on the German Leopard 2A5 hulls, because it was scheduled for adoption at a later time, it would have been added simultaneously with a new turret with the 140 mm L/48 NPzK smoothbore gun, as this would already require a more extensive rework of the hull (for example modifying the ammo racks to be suitable for 140 mm two-piece ammunition). The Leopard 2A7V will be the first German version too feature hull add-on armor modules, although this might be "E" or "F" type armor.
 
 
I haven't seen any texts, but a set of photographs of an armor array being tested. It consists of a thick steel plate, a large box labeled "Sonderpanzerung" (special armor), two further thick steel plates followed by a number of several other plates, some of which appear to be non-metallic. I was told that the thick steel plates have a relatively low hardness, but are used to simulate thinner plates of very high-quality (and very expensive) ballistic steel. There is no external armor module.
In front of the armor array is a sign from the German WTD saying that this array is being tested against the LKE1 APFSDS at a range of 2,000 meters.
 
The other photos show the three thick steel plates after the armor array was hit: one shows the exterior of all three plates, each showing the marks of the APFSDS penetrator. Another photograph shows the inner side of the three thick steel plates: two of them have been completely penetrated, while the other one has only a dent of the APFSDS penetrator. There is also a ruler/measurement rod, which suggest that the "Sonderpanzerung" is about 500 mm thick only. The steel plates are about 100 mm thick, but supposedly they are made of mild steel; the actual ballistic steel would be some fancy type of high hardness/triple hardness steel providing a much higher level of protection per weigth and thickness.
 
I actually haven't seen any proof that this armor belongs to the late Leopard 2A4 tank, but I consider the source very trustworthy. This armor was supposedly offered during the early 1990s as a cheap upgrade option to several Leopard 2 users, who didn't want to pay for the more expensive Leopard 2A5 upgrade, which is why I believe this is the "D" technology armor. According to different authors, there are (unconfirmed) rumors about the late Leopard 2A4 armor featuring titanium and tungsten, which might be broadly similar in to the DU armor of the M1A1 HA (at least the M1A2 SEP uses titanium to allow improving the armor protection without increasing the mass of the armor considerably). It is worth noting that AFAIK only the Leopard 2A4 with "D" technology is actually heavier than the Leopard 2A4 with "B" technology, apparently by 1.45 tonnes (at least the weight 56.6 tonnes has been quoted for the late Leopard 2A4). The M1A1 HA upgrade is heavier, but might cover more surface area and might have initially lacked the titanium weight saving measure.
 
I know that the "I have access to secret sources" argument is very weak, but the details about this armor come from a source that is located in one of the countries to which the Leopard 2A4 armor upgrade was offered during the 1990s. As it was never purchased by this country, the documents have only a low level of classification (IIRC every tank commander can access them).
 
 
As far as I know it should be hollow, at least for the early version of the Leopard 2.

I hate to barge into someone else's arguments, but several (almost all of his last post really) of DarkLabor's points don't really make sense.
 
 
British representatives still made exorbitant claims about Challenger after it's production run was effectively over despite the fact that we now know from leaked British documents their claims were bunk. People still believe what they want even after a project is over. And GIAT keeping FCS and Armor data "THE MOST protected data" is not unique to them either.
 
 
"Weak points" are not the same weaknesses between tanks. Even assuming that hit was through a weakpoint, it doesn't say much for the LeClerc's design that it managed to get hit in one. The Abrams has a comparatively fragile hatch, and yet in all the times they got hit in the mideast, I do not recall a hit managing to be landed clean on that hatch. No Chally 2 was knocked out to a hit to the drivers' optics despite the enormous chasm that was cut in the glacis armor for it. This suggests that the weakpoint on LeClerc is relatively large.
 
 
The best proof for the accuracy of the Swedish armor CAD models is the fact that neither the Germans or US (who also keep their exact data secret) complained about inaccuracies in modeling. There's also the fact that not a single outside test of LeClerc ever, has praised its armor in relation to late model Abrams or Leo 2s.
 
 
As to Greek trials - SH never claimed that the Radios were a crucial thing or a corner stone - just said they interfered. That they used the heavier tropical model does not stop them from reducing the weight of that relative to a normal tropical, which is what I am sure SH meant.
 
 
I already touched on this - KMW and GDLS do not openly discuss Abrams or Leopard 2 protection either. Literally nobody does, and SH is well aware of this. And yes, you have to get permission from the relevant export control authorities to get data on those vehicles as well. So the Swedes could jump through all the hoops with GLDS and KMW, but magically not with GIAT?
 
 
SH_MM is far from a "random retard", which is why I wrote this post. If your contacts are in the French army, of course they are going to say the LeClerc is the best. Everyone in the British army continued to say Challenger (both times!) was the best even after embarrassing performances that saw them lose time and again in trials. It is not in the interest of the French army to say their tank isn't the best, and it's also in their interest to tell everyone joining the armored force in France that their tank is the best. Troops in M1A1s in the late 80s were told that the vehicle could deal with every latest and greatest Soviet battlewagon without issue, and that they had armor capable of resisting whatever the Soviets could throw at them. We now know both of these to be categorically false, and that analysts at the time were aware of it in secret.
 
 
You just contradicted yourself. You said "it is the same as the other [...]" and that these drawings came from GIAT while the other is somehow "just a some stuff put together by the FMV". Which is it? Are the turret designs different, or was the FMV model correct?
 
 
That original statement you made was in fact very silly: "The engineers were not taking into account the other western MBTs when designing the Leclerc. They comply with the established specifications that took into account the latest warnings in the WarPact threats." When designing the Abrams, design specs were entirely based on hypothetical Soviet threats. Same with Leopard 2, same with Challenger. There was never a spec in Challenger that said: "we should make sure the armor is similar to Leopard 2, or better than Abrams".
 

don't know where you get 455HB for serial postwar casted soviet turret, but T-62, T-72 and T-64 uses SBL-2 steel which has hardness up to 277HB(Impression Diameter - 3,65mm) and tensile strength up to 882MPa 

40 & 30rnd experimental 5,45x39. OTs-12 "Tiss" / OTs-14 "Groza" 9x39. Experimental SVK / SVK-S 6x49.

You are a communist, Ivan! Communist looks into the sight - sees the enemy

I still remember what one ex-Soviet tank company commander told me after he went to Israel and served on Merkavas - "Agava sights are such type of sights where when you look in it, you are not sure if it is broken or should work like this"

I updated the model to resemble the mock-up

I made a model of the T-34M:



Astute viewers will notice that the commander's cupola is wrong - it's supposed to be a T-50 cupola rather than the T-34/85 model I stuck on.
 
Rivet counters will notice that the exhausts don't have the crazy bolt arrangement they should have (and are kind of the wrong shape), the front hooks are missing, the radio antenna is missing, the hull periscopes are missing, and that the turret periscopes are of the wrong type.

This case would have been very funny if it wasn't so stupid and broke a human life.

Also few rare photo from Directorate A facility (i guess).

 
Some of them translated:
 
Also, MP-5s if i see it right.