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   One thing that still bothers me - it is turret. The turretless missiles-only equipped tanks are still too specialized (can't fill up tanks jobs as well as current cannon-equipped tanks), but in a future, they may have serious advantage in form of using armor from turret to increase hull protection. Object 299-based missile tank/support tank is what i am thinking about - crew capsule, no turret, 30 powerfull missiles with higher range and better accuracy, capabilities to strike at high-speed targets. 

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Object 780:

 

wa3vYB4.jpg

27Jfxqn.jpg

 

Very interesting way to do driver-in-turret.  The trunnions for the gun are moved very far forward, and the breech is short enough that the driver can simply be located in the center of the turret.  This eliminates problems of driver disorientation while the turret rotates and simplifies the driver position.  No counter-rotating mechanism either; the driver just sits on the hull floor!

 

This obviously places some tough restrictions on gun recoil length.

 

I also like how the hull fuel tanks double as protection, and the armored bulkhead behind the fuel tank around the turret basket.

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Looking at Merkava tanks and Soviet MBTs, i start to feel that low-level conflicts create a situation when less weight/volume/armor -efficient designs become preferable.

Does Soviet tank design shines only in "high numbers law"-events, when smaller size and armor layout shows their core ideas if big number of tanks was involved in conflict?

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Merkava's ginormous hull is more a side-effect of the engine choices the Israelis had available when they designed the mk 1.  The air-cooled diesel is huge and requires a huge, tall hull to house.  The Swiss NKPz design was also engine-forward, and it wasn't anywhere near as tall.  If you purpose-design a very flat engine for an engine-forward tank you get object 416, which is a pancake.

 

The Merkava mk IV uses a liquid-cooled engine, but it's probably too late now to re-design the entire damn tank to make it squatter.  Instead they just cleaned up the glacis design a little.

 

Merkava has a reputation today as a premier asymmetric/low-level conflict design, but remember that the mk 1, where most of the weird design decisions were made, wasn't designed to fight Hamas and Hezbollah.  It was designed to fight Syria and Egypt.  To my eye the merkava mk 1 looks like the ideal tank for re-fighting the 1973 Golan Heights campaign.  It has an extremely small turret silhouette from the front, and the exposed portions of the turret have lots of well-sloped and spaced armor.  The rear door allows for easy re-supply of ammo in combat (which was a problem in 1973), and it's the only Western tank that does not use Diehl tracks because the Israelis are worried about the end connectors getting bashed off by all the rocks in the Golan.

 

None of the compromises made in the bigger MBTs seem that helpful in urban combat to me.  The turrets are taller to allow better gun depression.  WTF use is gun depression in a city?

 

T-72s haven't done that well in Syria, it's true, but these have been older T-72s until quite recently, without the latest armor and thermal optics.  Also, the ammunition storage isn't the safest.

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Merkava's ginormous hull is more a side-effect of the engine choices the Israelis had available when they designed the mk 1.  The air-cooled diesel is huge and requires a huge, tall hull to house.  The Swiss NKPz design was also engine-forward, and it wasn't anywhere near as tall.  If you purpose-design a very flat engine for an engine-forward tank you get object 416, which is a pancake.

 

The Merkava mk IV uses a liquid-cooled engine, but it's probably too late now to re-design the entire damn tank to make it squatter.  Instead they just cleaned up the glacis design a little.

 

Merkava has a reputation today as a premier asymmetric/low-level conflict design, but remember that the mk 1, where most of the weird design decisions were made, wasn't designed to fight Hamas and Hezbollah.  It was designed to fight Syria and Egypt.  To my eye the merkava mk 1 looks like the ideal tank for re-fighting the 1973 Golan Heights campaign.  It has an extremely small turret silhouette from the front, and the exposed portions of the turret have lots of well-sloped and spaced armor.  The rear door allows for easy re-supply of ammo in combat (which was a problem in 1973), and it's the only Western tank that does not use Diehl tracks because the Israelis are worried about the end connectors getting bashed off by all the rocks in the Golan.

 

None of the compromises made in the bigger MBTs seem that helpful in urban combat to me.  The turrets are taller to allow better gun depression.  WTF use is gun depression in a city?

 

T-72s haven't done that well in Syria, it's true, but these have been older T-72s until quite recently, without the latest armor and thermal optics.  Also, the ammunition storage isn't the safest.

 

I remember a while back I was arguing with some scrub over at the WoT forum who kept insisting that the Merkava was designed for MOUT while the Abrams was not.  I kept trying to explain to him that both the Merkava and the Abrams were initially designed for fighting off hordes of Soviet designed tanks, albeit in different circumstances and environments.  Both vehicles have evolved over time to be useful for MOUT, but neither of them were designed with that as the central consideration.

 

In regards to engines, yes, US aircooled diesels are a bit large.  However, the bigger issue is that they are of fixed dimensions.  When dealing with an AVDS-1790, its a single unit, you can't adjust it's size, you have to design the vehicle around the engine to a certain extent.  With modern watercooled units like the MT-883, you can rearrange the cooling components to better fit your requirements.  For example, the powerplant of the Merkava 4 features an MT-883 mounted lengthwise so as to leave enough room on the side for the driver and the cooling units are arraigned so it can fit under sloping front armor.

 

engines2.jpg GD883_proE.gif

 

Now look at the powerpack for the Turkish Altay.  It's also an MT-883 but the engine is mounted transversely to take up less length (no need to leave space for the driver like in the front engine mounted Merkava) and the cooling components can be arraigned to take up more vertical space since it's in the back of the vehicle.

 

altay-tank-engine-assembly.jpg

 

So yes, the smaller MT-883 has an advantage it that it can be configured to meet different space requirements.  

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So there has been a lot of talking about engine placement and such, and a bit too about unmanned turrets. 

 

So my question is, what is do you guys think is the best autoloader design for a low profile unmanned turret?

 

For me it seems to be the T-64 style carousel autoloader, it design can support the 120x560mm NATO ammunition as possible even the 140mm shells too. But I really dislike one thing about it. It makes the hull tall, very tall, the internal space needs to be a little under 1000mm high, which makes the the vehicle much taller. And it makes it impossible to add longer one-piece ammunition later. Of course, by reducing the roof and floor thickness and angling the rounds you can save a few millimeters, but they both come with draw backs. 

 

One the other side of the spectrum you have a bustle autoloader.  In this design, the hull can be as low as the engine or crew compartment allows. But catch is that the ammunition has to be stored in the bustle. Since we can't have a 3m long bustle we have to make wider turret, and possibly taller.  This makes the turret heavy, maybe not as heavy as a manned one, but not really too much lighter.

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Why focus on one piece ammunition? If you have vertically stored two piece ammunition in a carousel, your hull can still be very low. 

Wouldn't this hurt the performance of APFSDS? Since the arrow can't be longer than the shell.

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You get more performance from long rod penetrators by making them longer than you do by burning more propellant.

 

Also, by surrounding the penetrator with propellant, you're just bringing the space efficiency of the round up to NATO standards, since 120mm rounds have the penetrator encased in propellant to begin with:

 

s8TfKOS.jpg

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Apart from ammunition volume. Does anyone have the measurements of a average man? (1,80m, 80kg, average soldier) preferably reclined. 

 

Look for "SAE ergonomic standard", and you may come close.

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Earlier, you guys spoke about engine placement and such. And one design is the sponsons mounted engine. Is it more worth it than a power pack? A smaller tank for a longer locomotive system switch.

 

What do you guys think?

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Sponson mounted engines seem like a good idea for IFVs and APCs.  I'm not so sure that an engine powerful enough to fit into a reasonably-sized sponson would be powerful enough to move an MBT.  If you put turbines in each sponson then maybe, but you might have to forego recuperators for the turbines because of the space constraints, and as the T-80 shows, turbines without recuperators use a lot of fuel.

 

It would probably also have to use an electrical or hydraulic transmission, and these have historically been less efficient than mechanical transmissions.

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I have been reading a bit about fully electric propulsion systems, as well as breaking systems, suspension and such. 

 

And two things made me wonder.....

 

First, could anyone help explain the pros and cons of live and dead track?

article-1354096-0D0EB1A9000005DC-436_634sisis6.jpg?quality=65&strip=all&w=780&h=3

 

As far as I know, dead track tends to be cheaper and simpler, but throws tracks easier. While live is the opposite, harder to throw track, but more expensive and complex.

 

But then we have tanks like the Strv 103:

STRV103-5.JPG

 

Which was known to be almost impossible to throw a track with.

 

 

Second, ​we electromagnetic suspension:

electromagnetic-suspension-system-20-638

To summarize, it appears the be similar to hydropuematic suspension, but is claimed to use one fourth of the power (take with a grain of salt). It is also said to have a longer lifespan than the average suspension.

In the case of power shortage or loss of power, the suspension acts as a normal suspension, although probably very poorly.

 

It can be used as a active suspension, and does not appear to take away internal volume. So does this mean that it is directly better than hydropuematic suspension? And as a last note, it can generate electricity through vibration and movement in the suspension. 

 

I like innovating new ideas but, there has the be a mayor drawback with this system.

 

 

Mvh

Xoon.

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I have been reading a bit about fully electric propulsion systems, as well as breaking systems, suspension and such. 

 

And two things made me wonder.....

 

First, could anyone help explain the pros and cons of live and dead track?

article-1354096-0D0EB1A9000005DC-436_634sisis6.jpg?quality=65&strip=all&w=780&h=3

 

 

 

"Live" track has rubber bushings between each link that cause a slight curl if you lay the stuff out flat on pavement.  "Dead" track does not have this.  You can't really tell if track is live or dead when it's mounted on a tank.  Whether or not track sags when it's mounted on a tank is a function of how much tension is applied to it (usually by adjusting the length or angle of the arm that the idler wheel rides on).  Some tanks have gone from using dead track to live track; IIRC, early T-64s had dead track and later ones had live track, but you couldn't really tell just by looking at them.

 

The main purpose of the rubber bushings, as far as I can tell from technical treatises on the matter, is to reduce the wear on the connections between the tracks.

 

 

But then we have tanks like the Strv 103:

STRV103-5.JPG

 

Which was known to be almost impossible to throw a track with.

 

 

 

I'm dubious that live track would be any harder to throw.  Is the slight inward curvature supposed to make it hug the running gear better?  If it does help, the effect would be relatively small.

 

I suspect that the confusion comes from people who think that dead track lies slack on the return rollers or road wheels, while live track is tight.  This isn't necessarily the case though:

 

Chieftain-100-Tank11.jpg

 

Chieftains have dry, single pin track with no rubber bushings around the track pins, just like a T-55.  But the track tension specification is much tighter, as you can see.  There's almost no slack there.

 

Why is there so much slack in the T-55's tracks?  I suspect it's a leftover of the Christie track design.  Yes, the T-55 does not use Christie suspension, the road wheels are sprung by torsion bars.  However, the running gear design is still descended from the Christie designs.  BT-7 basically was a dieselized Christie tank, T-34 was a Christie tank, but with more armor, no ability to run off its tracks and a +4 bonus against fascists, T-44 was a T-34 with the engine mounted sideways and torsion bars instead of the hull interior coil springs and bell cranks, and it was only with later T-54 models that they finally ditched the track horn drive tooth system and put a toothed drive sprocket on.  So the Soviets kept the low track tension of the original Christie suspension design all the way through the T-62.  Christie tanks have low track tension because track tension causes friction, and friction slows the tank down.  J Walter Christie believed that tanks should be so fast that they create sonic booms that disorient and confuse the enemy.

 

The main reason the S-tank is almost impossible to de-track, even if it's pulling insane handbrake turns is that the ratio of the contact length of the tracks to distance between track centers is extremely small:

 

 

The longer you make tank tracks the more sideways force there is on the foremost and rearmost sections of the track.

 

Jrw63tP.gif

 

If you make the tracks short like they are in the S-tank, you make it harder to throw the track.  But you sacrifice ditch-crossing ability, and you make the ground pressure higher because there's less ground contact.

 

 

Second, ​we electromagnetic suspension:

electromagnetic-suspension-system-20-638

To summarize, it appears the be similar to hydropuematic suspension, but is claimed to use one fourth of the power (take with a grain of salt).

 

I'm pretty skeptical already because hydropneumatic suspension does not require energy input from the tank.  If it did tanks with hydropneumatic suspension would sink to the ground when the engines were turned off, which clearly does not happen.

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"Live" track has rubber bushings between each link that cause a slight curl if you lay the stuff out flat on pavement.  "Dead" track does not have this.  You can't really tell if track is live or dead when it's mounted on a tank.  Whether or not track sags when it's mounted on a tank is a function of how much tension is applied to it (usually by adjusting the length or angle of the arm that the idler wheel rides on).  Some tanks have gone from using dead track to live track; IIRC, early T-64s had dead track and later ones had live track, but you couldn't really tell just by looking at them.

 

The main purpose of the rubber bushings, as far as I can tell from technical treatises on the matter, is to reduce the wear on the connections between the tracks.

 

 

 

I'm dubious that live track would be any harder to throw.  Is the slight inward curvature supposed to make it hug the running gear better?  If it does help, the effect would be relatively small.

 

I suspect that the confusion comes from people who think that dead track lies slack on the return rollers or road wheels, while live track is tight.  This isn't necessarily the case though:

 

Chieftain-100-Tank11.jpg

 

Chieftains have dry, single pin track with no rubber bushings around the track pins, just like a T-55.  But the track tension specification is much tighter, as you can see.  There's almost no slack there.

 

Why is there so much slack in the T-55's tracks?  I suspect it's a leftover of the Christie track design.  Yes, the T-55 does not use Christie suspension, the road wheels are sprung by torsion bars.  However, the running gear design is still descended from the Christie designs.  BT-7 basically was a dieselized Christie tank, T-34 was a Christie tank, but with more armor, no ability to run off its tracks and a +4 bonus against fascists, T-44 was a T-34 with the engine mounted sideways and torsion bars instead of the hull interior coil springs and bell cranks, and it was only with later T-54 models that they finally ditched the track horn drive tooth system and put a toothed drive sprocket on.  So the Soviets kept the low track tension of the original Christie suspension design all the way through the T-62.  Christie tanks have low track tension because track tension causes friction, and friction slows the tank down.  J Walter Christie believed that tanks should be so fast that they create sonic booms that disorient and confuse the enemy.

 

The main reason the S-tank is almost impossible to de-track, even if it's pulling insane handbrake turns is that the ratio of the contact length of the tracks to distance between track centers is extremely small:

 

 

The longer you make tank tracks the more sideways force there is on the foremost and rearmost sections of the track.

 

Jrw63tP.gif

 

If you make the tracks short like they are in the S-tank, you make it harder to throw the track.  But you sacrifice ditch-crossing ability, and you make the ground pressure higher because there's less ground contact.

 

 

I'm pretty skeptical already because hydropneumatic suspension does not require energy input from the tank.  If it did tanks with hydropneumatic suspension would sink to the ground when the engines were turned off, which clearly does not happen.

So, what is the point of a return roller?

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So, what is the point of a return roller?

 

They aren't needed if the road wheels are big enough; plenty of T-55s, M109s and M113s out there.  Per Ogorkiewicz the full diameter road wheel with no return roller configuration has the lowest rolling resistance.

 

But for best suspension performance on rough terrain the suspension needs a lot of travel distance.  Road wheels that are big enough to not need return rollers are already rather tall, and giving them adequate space to travel up and down enough to damp out the bumps from high-speed off-road travel will make the hull taller.

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They aren't needed if the road wheels are big enough; plenty of T-55s, M109s and M113s out there.

 

But for best suspension performance on rough terrain you need lots of suspension travel.  If you have road wheels that are big enough to act as return rollers, it's harder to give them enough space to travel up and down without making the hull unacceptably tall.

Ah, I see, thanks for all the info Col!

 

Mvh

Xoon.

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The number of road wheels and return rollers and how they contact the track probably has some influence on how well the track stays on, but what I've heard from people who drive AFVs is that the track usually slips off over either the drive sprocket or the idler wheel.  This would explain the little accessory idler wheels right next to the drive sprocket on the M46 and panther; gotta keep the track tight near the drive sprocket so it can't walk off.

 

I wonder if vehicles with driven road wheels and no idlers or return rollers, like the tetrarch were any better at keeping track on.  Sadly, the Soviets never actually made the MT-25.

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      Non-structural passive materials:

                                                                  iii.     HHA

      Steel, approximately 500 BHN through-hardened. Approximately twice as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 25mm.
      Density- 7.8g/cm^3.

                                                                  iv.     Glass textolite

      Mass efficiency vs RHA of 2.2 vs CE, 1.64 vs KE.

      Thickness efficiency vs RHA of 0.52 vs CE, 0.39 vs KE.
      Density- 1.85 g/cm^3 (approximately ¼ of steel).
      Non-structural.

                                                                   v.     Fused silica

      Mass efficiency vs RHA of 3.5 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 1 vs CE, 0.28 vs KE.
      Density-2.2g/cm^3 (approximately 1/3.5 of steel).
      Non-structural, requires confinement (being in a metal box) to work.

                                                                  vi.     Fuel

      Mass efficiency vs RHA of 1.3 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 0.14 vs CE, 0.1 vs KE.

      Density-0.82g/cm^3.

                                                                vii.     Assorted stowage/systems

      Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE.

                                                               viii.     Spaced armor

      Requires a face of at least 25mm LOS vs CE, and at least 50mm LOS vs KE.

      Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 10 cm air gap.
      Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette.

      Reactive armor materials:

                                                                  ix.     ERA-light

      A sandwich of 3mm/3mm/3mm steel-explodium-steel.
      Requires mounting brackets of approximately 10-30% cassette weight.

      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                   x.     ERA-heavy

      A sandwich of 15mm steel/3mm explodium/9mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                  xi.     NERA-light

      A sandwich of 6mm steel/6mm rubber/ 6mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

                                                                 xii.     NERA-heavy

      A sandwich of 30mm steel/6m rubber/18mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

      The details of how to calculate armor effectiveness will be detailed in Appendix 1.

      b.      Firepower

                                                                    i.     2A46 equivalent tech- pressure limits, semi-combustible cases, recoil mechanisms and so on are at an equivalent level to that of the USSR in the year 1960.

                                                                   ii.     Limited APFSDS (L:D 15:1)- Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS.

                                                                  iii.     Limited tungsten (no more than 100g per shot)

                                                                  iv.     Californian shaped charge technology- 5 CD penetration for high-pressure resistant HEAT, 6 CD for low pressure/ precision formed HEAT.

                                                                   v.     The general issue GPMG for the People’s Auditory Forces is the PKM. The standard HMG is the DShK.

      c.       Mobility

                                                                    i.     Engines tech level:

      1.      MB 838 (830 HP)

      2.      AVDS-1790-5A (908 HP)

      3.      Kharkov 5TD (600 HP)

                                                                   ii.     Power density should be based on the above engines. Dimensions are available online, pay attention to cooling of 1 and 3 (water cooled).

                                                                  iii.     Power output broadly scales with volume, as does weight. Trying to extract more power from the same size may come at the cost of reliability (and in the case of the 5TD, it isn’t all that reliable in the first place).

                                                                  iv.     There is nothing inherently wrong with opposed piston or 2-stroke engines if done right.

      d.      Electronics

                                                                    i.     LRFs- unavailable

                                                                   ii.     Thermals-unavailable

                                                                  iii.     I^2- limited

      3.      Operational Requirements.

      The requirements are detailed in the appended spreadsheet.

      4.      Submission protocols.

      Submission protocols and methods will be established in a follow-on post, nearer to the relevant time.
       
      Appendix 1- armor calculation
      Appendix 2- operational requirements
       
      Good luck, and may Hubbard guide your way to enlightenment!
    • By Collimatrix
      Shortly after Jeeps_Guns_Tanks started his substantial foray into documenting the development and variants of the M4, I joked on teamspeak with Wargaming's The_Warhawk that the next thing he ought to do was a similar post on the T-72.
       
      Haha.  I joke.  I am funny man.
       
      The production history of the T-72 is enormously complicated.  Tens of thousands were produced; it is probably the fourth most produced tank ever after the T-54/55, T-34 and M4 sherman.
       
      For being such an ubiquitous vehicle, it's frustrating to find information in English-language sources on the T-72.  Part of this is residual bad information from the Cold War era when all NATO had to go on were blurry photos from May Day parades:
       

       
      As with Soviet aircraft, NATO could only assign designations to obviously externally different versions of the vehicle.  However, they were not necessarily aware of internal changes, nor were they aware which changes were post-production modifications and which ones were new factory variants of the vehicle.  The NATO designations do not, therefore, necessarily line up with the Soviet designations.  Between different models of T-72 there are large differences in armor protection and fire control systems.  This is why anyone arguing T-72 vs. X has completely missed the point; you need to specify which variant of T-72.  There are large differences between them!
       
      Another issue, and one which remains contentious to this day, is the relation between the T-64, T-72 and T-80 in the Soviet Army lineup.  This article helps explain the political wrangling which led to the logistically bizarre situation of three very similar tanks being in frontline service simultaneously, but the article is extremely biased as it comes from a high-ranking member of the Ural plant that designed and built the T-72.  Soviet tank experts still disagree on this; read this if you have some popcorn handy.  Talking points from the Kharkov side seem to be that T-64 was a more refined, advanced design and that T-72 was cheap filler, while Ural fans tend to hold that T-64 was an unreliable mechanical prima donna and T-72 a mechanically sound, mass-producible design.
       
      So, if anyone would like to help make sense of this vehicle, feel free to post away.  I am particularly interested in:
       
      -What armor arrays the different T-72 variants use.  Diagrams, dates of introduction, and whether the array is factory-produced or a field upgrade of existing armor are pertinent questions.
       
      -Details of the fire control system.  One of the Kharkov talking points is that for most of the time in service, T-64 had a more advanced fire control system than contemporary T-72 variants.  Is this true?  What were the various fire control systems in the T-64 and T-72, and what were there dates of introduction?  I am particularly curious when Soviet tanks got gun-follows-sight FCS.
       
      -Export variants and variants produced outside the Soviet Union.  How do they stack up?  Exactly what variant(s) of T-72 were the Iraqis using in 1991?

      -WTF is up with the T-72's transmission?  How does it steer and why is its reverse speed so pathetically low?
       
       
    • By Sturgeon
      This is the place for flame wars about rifle-caliber MGs versus autocannons for tank coaxial weaponry. First, we have Ensign's blog post about tank machine guns:
       

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