Alternative History Armoured Fighting Vehicles Part 3

[Bougnas]

After yet another study of the timeline of tank engines, I think there was some potential with the Meteor:

- Development could start in 1939 or early 1940 rather than late 40/early 41 using rejected parts and the few crashes there were until this point, to get a few extra months of advance.
- the bigger one IMO is getting the Americans to produce Meteor as soon as possible and in as many companies as possible much like the Packard Merlin, rather than the other way around where the US tried to produce Ford V8s for the UK. The Meteor, especially with the above POD, was available earlier than the GAA and can mature earlier (1941, 42 at the latest) while the GAA didn't enter production until mid-43 in one factory and wasn't fixed until 1944.
The Meteor is less efficient than the Ford engine (heavier, less power-dense, uses more steel parts so a bit less efficient for cooling), but it still compares favourably with the other engines (lighter and less complex than the diesel and Multibank, more powerful, uses less oil and fuel than the radial and is more reliable than it, more compact than all of them) which is a big plus considering it can be available sooner than the best engine and can actually meet US requirements for standardizing on a single engine (family). It provides a synergy between British and American R&D and production efforts.

The US can also potentially produce enough Meteors to supply the British with those, which helps a lot as Britain couldn't really produce both tanks and engines in reasonnable numbers, not until 1944 at least. The combination of the two PODs also opens the possibility of avoiding Cavalier and Centaur if the Meteor is proven early enough, so British production through 42-43 is more efficient. It might even be possible to exploit Meteor for late Crusader production.

On the American side, the extra power and torque of the Meteor over even the GAA makes heavier tanks a bit more practical (Jumbo, T2X series). It starts at 550bhp and can actually be improved over time, especially with US engineering help and 80 octane fuel (while the British used lower octane petrol). 650 bhp was obtained OTL postwar with a higher compression ratio, but with better fuel and earlier work 600-700 bhp might be feasible late in the war, which makes this engine even more viable for a Pershing. Yet, it is also within the capability of US Torqmatic and Sherman transmissions unlike some of the higher power US engines which were too powerful to be used during the war.

The Meteorite, of course, is also a reasonnable option for lighter US vehicles. I think it did compare favourably with the Cadillac powerplant in the M5 Stuart/M24 Chaffee, being more powerful for similar dimensions and weight.

In hindsight, the desire of some American manufacturers to push for their own engines (Chrysler with the A65, Ford with their GAA/GAC instead of building Merlins and Meteors early on) was probably detrimental to the war effort since their designs appeared late (sometimes too late to be even used). What mattered for the Wallies was ramping up early rather than late.

 

[marathag]

After yet another study of the timeline of tank engines, I think there was some potential with the Meteor:

- Development could start in 1939 or early 1940 rather than late 40/early 41 using rejected parts and the few crashes there were until this point, to get a few extra months of advance.
- the bigger one IMO is getting the Americans to produce Meteor as soon as possible and in as many companies as possible much like the Packard Merlin

On to Packard, an even faster way is to look at their InterWar 1A-2500 or to Kermath and their V-12 DOHC Sea Raider, that was 1558 cubic inches for 550hp.
It could run on 72 Octane.
Before the War, Packard was really trying hard to get the Navy to use their new Marine version of that 1A-2500 aircraft engine in the form of the supercharged 1200HP 3M-2500, but these needed higher octane AvGas, and by Wars end, needed 115/135 for 1800HP, along with an intercooler

So a fast way to get a 600HP Tank engine, is to use half the V-12, to a 1245 cubic inch Slant Six. leave out the supercharger, you get 450-500

A bit long, but no worse than the Soviet V2 diesel, Would fit in the M4A4 length hull

 

[Bougnas]

On to Packard, an even faster way is to look at their InterWar 1A-2500 or to Kermath and their V-12 DOHC Sea Raider, that was 1558 cubic inches for 550hp.
It could run on 72 Octane.
Before the War, Packard was really trying hard to get the Navy to use their new Marine version of that 1A-2500 aircraft engine in the form of the supercharged 1200HP 3M-2500, but these needed higher octane AvGas, and by Wars end, needed 115/135 for 1800HP, along with an intercooler

So a fast way to get a 600HP Tank engine, is to use half the V-12, to a 1245 cubic inch Slant Six. leave out the supercharger, you get 450-500

A bit long, but no worse than the Soviet V2 diesel, Would fit in the M4A4 length hull

I was thinking about prewar Vees too, sadly the US Ordnance wasn't very interested in alternative engines before 1940. I'm still surprised that only Ford bothered to offer a Vee for tanks when so many options existed. Granted many of them were Hyper Engines so a bit too advanced.

I kinda wish the Curtiss 1800 cu aircraft engine tested in 1934-35 was used instead of the Wright R975 just for the memes, it's hilariously narrow.

 

[Not James Stockdale]

This is my basic conception of main battle tank generations. My general thinking is that, if a given tank is a main battle tank, the tank it replaced was probably also a main battle tank. This means that I will be going all the way back to WWII-era medium tanks. However, to ultimately identify a split between interwar light and medium tanks and what I consider to be main battle tanks, I have to establish some concrete definitions based primarily on the Iron Triangle.

First, main battle tanks have mobility above and beyond that of foot-mobile infantry and horse cavalry units, in terms of both tactical and operational speed. Slow infantry or heavy tanks designed to support infantry are thus excluded. Second, main battle tanks have shell-proof armor and are thus protected against contact-fused high-explosive shells fired by 3-inch field guns. Light tanks with armor capable of standing up only to small-caliber rifle or machine gun fire are thus excluded. This, main battle tanks are equipped with guns selected, at least in part, for their anti-tank capabilities. Support and escort tanks equipped with low-velocity howitzers are thus excluded. Additionally, main battle tanks should be the most common tank in large mechanized formations.

The first generation of tanks fitting this definition originated in the late pre-war period. These are tanks like the M4 Sherman, Panzer III, Cromwell, and T-34. Most use either a 2-inch class anti-tank gun (5 cm KwK 38 or OQF 6-pdr) or 3-inch class field guns with AP ammunition (76 mm F-34 or 75 mm Gun M3). Engine power ranges from 300 to 500 hp and weight from 20 to 30 tons. Manticore's tank in this period is the Medium 25-ton, with an 8V-71 diesel providing 325 hp, a 3-inch field gun, and roughly 2 inches of frontal armor. Generation 1.5 tanks are equipped with higher-velocity 3-inch class anti-tank guns, such as the M4 (76) Sherman with the 76 mm Gun M1, the T-34(85) with the 85 mm D-5T, the Comet with the 77 mm HV gun, or the Panzer IV F-2 with the 7.5 cm KwK 40. The comparable Manticoran tank is the Medium 30-ton, with a 12V-71 diesel providing 450 hp, a 76 mm Gun M1, and roughly 2.5 inches of frontal armor.

The second generation of main battle tanks are larger tanks designed in light of experience gained early in the war. These tanks began to enter service between 1943 and 1945. Examples of this generation include the Panther, the M26 Pershing, the Centurion, and the T-44. These tanks were generally equipped with very heavy 3-inch to 3.5-inch anti-tank guns. Generally speaking, the QF 17-pdr, the 7.5 cm KwK 42, and the 90 mm Gun M3 are all very close in size and muzzle energy. Manticore's second generation tank is the Medium 40-ton, with a 16V-71 diesel providing 600 hp, a 90 mm Gun M3, and roughly 3 inches of frontal armor.

The third generation of main battle tanks are those designed in the immediate post-war era to reflect advances in manufacturing technology beyond what was accomplished during the war. Tanks like the M47 and M48 Patton and T-54 and T-55 family were introduced in the late 1940s and formed the main strength of their nations' tank fleets during the 1950s. The Manticoran example is the Medium 50-ton, with a 16V-71T providing 750 to 800 hp, a long 90 mm gun with increased chamber pressure and/or volume over the 90 mm Gun M3, and roughly 4 inches of frontal armor.

The fourth generation of main battle tanks represented the final and most advanced development of WWII era tank designs. These tanks were introduced in the 1960s and were front-line tanks primarily through the 1960s and 1970s. Examples of the generation include the M60 Patton, the T-62, the Chieftain, and the Leopard 1. Based on the simultaneous proliferation first of HEAT munitions and infantry anti-tank missiles, design choices diverged significantly between light and fast tanks like the AMX-30 and Leopard 1 and very heavy defensively oriented tanks like the Chieftain. Manticore's tank is the MBT-60, a 50-ton tank that continues with the basic architecture of the Medium 50-ton. The engine will be an AVDS-1790 providing roughly 800 hp and the gun will be a 105 mm smoothbore. Armor is still an open question, but the only realistic way to match the weight-efficient cast armor of the M47 and M48 without resorting to huge castings is with spaced armor and NERA-like gapfiller.

The fifth generation of main battle tanks are the first to all but completely break with the design heritage of WWII-era tanks. The most prominent examples are the American/German MBT-70, the German Leopard 2K, and the Soviet T-64 and T-72, employing more advanced fire control systems, digitally controlled diesel engines, and smoothbore guns. These tanks originated in the late 1960s and early 1970s and were designed before the introduction of large composite armor arrays. Manticore's tank will be designated the MBT-70, powered by a 1,500 hp turbodiesel, armed with a 120 mm Delta gun, and protected by spaced and composite (non-ceramic) armor. Weight will probably be limited to 60 tons, although setting a goal of roughly 50 tons would be likely. At the lighter weight, armor protection would be fairly minimal. Introduction into service planned for no later than 1974.

The sixth generation of main battle tanks are designed fully around the more advanced composite armor arrays developed in the 1970s, including heavy metals and ceramic components to enhance protection against both kinetic and chemical energy threats. Examples of these tanks introduced in the early 1980s include the Leopard 2, M1 Abrams, and Challenger 1, while a number of additional vehicles such as the Leclerc, Ariete, and Challenger 2 were introduced in the 1990s. With the fall of the Soviet Union and the effective cessation of Russian tank development for more than a decade, almost all new tank models introduced since 1980 have been modernized sixth generation MBTs. Manticore's MBT-80 will share a very similar hull to the MBT-70, but will use a new turret with large composite armor arrays. The front nose of the hull will also have to be modified to fit the required armor arrays. Design weight will be limited to 65 tons, in line with the Leopard 2 and earlier variants of the M1 Abrams.

The question of what constitutes the next generation of main battle tank is now relevant. Japan and South Korea have both introduced replacements (Type 10 and K2) for their previous tanks (Type 90 and K1), but it is not clear if these new tanks actually represent a new generation of main battle tanks based on advances in technology and capability.

 

[GrahamB]

After yet another study of the timeline of tank engines

I feel somewhat shameful that I had to reread that sentence because my brain defaulted to steam locomotives.

 

[cortz#9]

This is my basic conception of main battle tank generations. My general thinking is that, if a given tank is a main battle tank, the tank it replaced was probably also a main battle tank. This means that I will be going all the way back to WWII-era medium tanks. However, to ultimately identify a split between interwar light and medium tanks and what I consider to be main battle tanks, I have to establish some concrete definitions based primarily on the Iron Triangle.

First, main battle tanks have mobility above and beyond that of foot-mobile infantry and horse cavalry units, in terms of both tactical and operational speed. Slow infantry or heavy tanks designed to support infantry are thus excluded. Second, main battle tanks have shell-proof armor and are thus protected against contact-fused high-explosive shells fired by 3-inch field guns. Light tanks with armor capable of standing up only to small-caliber rifle or machine gun fire are thus excluded. This, main battle tanks are equipped with guns selected, at least in part, for their anti-tank capabilities. Support and escort tanks equipped with low-velocity howitzers are thus excluded. Additionally, main battle tanks should be the most common tank in large mechanized formations.

The first generation of tanks fitting this definition originated in the late pre-war period. These are tanks like the M4 Sherman, Panzer III, Cromwell, and T-34. Most use either a 2-inch class anti-tank gun (5 cm KwK 38 or OQF 6-pdr) or 3-inch class field guns with AP ammunition (76 mm F-34 or 75 mm Gun M3). Engine power ranges from 300 to 500 hp and weight from 20 to 30 tons. Manticore's tank in this period is the Medium 25-ton, with an 8V-71 diesel providing 325 hp, a 3-inch field gun, and roughly 2 inches of frontal armor. Generation 1.5 tanks are equipped with higher-velocity 3-inch class anti-tank guns, such as the M4 (76) Sherman with the 76 mm Gun M1, the T-34(85) with the 85 mm D-5T, the Comet with the 77 mm HV gun, or the Panzer IV F-2 with the 7.5 cm KwK 40. The comparable Manticoran tank is the Medium 30-ton, with a 12V-71 diesel providing 450 hp, a 76 mm Gun M1, and roughly 2.5 inches of frontal armor.

The second generation of main battle tanks are larger tanks designed in light of experience gained early in the war. These tanks began to enter service between 1943 and 1945. Examples of this generation include the Panther, the M26 Pershing, the Centurion, and the T-44. These tanks were generally equipped with very heavy 3-inch to 3.5-inch anti-tank guns. Generally speaking, the QF 17-pdr, the 7.5 cm KwK 42, and the 90 mm Gun M3 are all very close in size and muzzle energy. Manticore's second generation tank is the Medium 40-ton, with a 16V-71 diesel providing 600 hp, a 90 mm Gun M3, and roughly 3 inches of frontal armor.

The third generation of main battle tanks are those designed in the immediate post-war era to reflect advances in manufacturing technology beyond what was accomplished during the war. Tanks like the M47 and M48 Patton and T-54 and T-55 family were introduced in the late 1940s and formed the main strength of their nations' tank fleets during the 1950s. The Manticoran example is the Medium 50-ton, with a 16V-71T providing 750 to 800 hp, a long 90 mm gun with increased chamber pressure and/or volume over the 90 mm Gun M3, and roughly 4 inches of frontal armor.

The fourth generation of main battle tanks represented the final and most advanced development of WWII era tank designs. These tanks were introduced in the 1960s and were front-line tanks primarily through the 1960s and 1970s. Examples of the generation include the M60 Patton, the T-62, the Chieftain, and the Leopard 1. Based on the simultaneous proliferation first of HEAT munitions and infantry anti-tank missiles, design choices diverged significantly between light and fast tanks like the AMX-30 and Leopard 1 and very heavy defensively oriented tanks like the Chieftain. Manticore's tank is the MBT-60, a 50-ton tank that continues with the basic architecture of the Medium 50-ton. The engine will be an AVDS-1790 providing roughly 800 hp and the gun will be a 105 mm smoothbore. Armor is still an open question, but the only realistic way to match the weight-efficient cast armor of the M47 and M48 without resorting to huge castings is with spaced armor and NERA-like gapfiller.

The fifth generation of main battle tanks are the first to all but completely break with the design heritage of WWII-era tanks. The most prominent examples are the American/German MBT-70, the German Leopard 2K, and the Soviet T-64 and T-72, employing more advanced fire control systems, digitally controlled diesel engines, and smoothbore guns. These tanks originated in the late 1960s and early 1970s and were designed before the introduction of large composite armor arrays. Manticore's tank will be designated the MBT-70, powered by a 1,500 hp turbodiesel, armed with a 120 mm Delta gun, and protected by spaced and composite (non-ceramic) armor. Weight will probably be limited to 60 tons, although setting a goal of roughly 50 tons would be likely. At the lighter weight, armor protection would be fairly minimal. Introduction into service planned for no later than 1974.

The sixth generation of main battle tanks are designed fully around the more advanced composite armor arrays developed in the 1970s, including heavy metals and ceramic components to enhance protection against both kinetic and chemical energy threats. Examples of these tanks introduced in the early 1980s include the Leopard 2, M1 Abrams, and Challenger 1, while a number of additional vehicles such as the Leclerc, Ariete, and Challenger 2 were introduced in the 1990s. With the fall of the Soviet Union and the effective cessation of Russian tank development for more than a decade, almost all new tank models introduced since 1980 have been modernized sixth generation MBTs. Manticore's MBT-80 will share a very similar hull to the MBT-70, but will use a new turret with large composite armor arrays. The front nose of the hull will also have to be modified to fit the required armor arrays. Design weight will be limited to 65 tons, in line with the Leopard 2 and earlier variants of the M1 Abrams.

The question of what constitutes the next generation of main battle tank is now relevant. Japan and South Korea have both introduced replacements (Type 10 and K2) for their previous tanks (Type 90 and K1), but it is not clear if these new tanks actually represent a new generation of main battle tanks based on advances in technology and capability.

So the first MBT was the Pz.III ausf. J?

 

[historyfool]

I´d argue that an important feature of the MBT is the ability to flexibly fight both armour and soft targets , thus a real dual purpose gun is necessary. So I´d start with the Panzer IV F2 the T-34 Model 41 and the M4 Sherman as proto-MBTs. Earlier Pz. IVs (with the right ammo) and T-34s could to some degree fill both roles, but both had guns a bit short for real tank on tank warfare and were not yet used as general purpose tanks. That started to develop only with these models of 41/42.

 

[cortz#9]

I would say the Panther was the first MBT.

 

[Leander]

I would say the Panther was the first MBT.

I would tend to agree with you based on gut feeling, but I cant realy come up with a good justification. @historyfool s definition of the "do everything" tank is pretty compelling.

 

[Lord Wyclif]

The original Royal Marines Armoured Support Group was formed during the Second World War. The Group consisted of two Armoured Support Regiments, each of two Armoured Support Batteries, plus an independent Armoured Support Battery. Each Battery consisted of four troops, with each troop equipped with four Centaur IV and one Sherman tank, giving a total of 80 Centaur and 20 Sherman tanks in the group,

Following their experiences in the Sarawak and Aden one of the regiments were reformed. Each troop consisted of four FV437 Pathfinder amphibious vehicles, one FV444 Scarab AVR(T). Support battery consisted of three FV431 self propelled anti tank gun and two FV442 mortar carriers. Pathfinders were armed with a single L20A1 machine gun and two L4 machine guns. The F444 Scarab mounted the turret of a Saladin armoured car. The 81mm mortar and the wombat anti-tank gun equipped the support batteries vehicles.

The regiment saw action during the Dhofar Rebellion, participating as part of the peacekeeping operations in Lebanon, Cyprus and Bosnia. All vehicles were upgraded in the 1990’s.

Along with the Australian conversions during the Vietnam War, Vickers developed the Cerberus. Basically the vehicle was an inexpensive tank with an Abbott’s hull with an improved engine, upgraded armour and a tank turret with the infamous L7 tank gun.

Export customers were Chile (70), Bahrain (12), Botswana (15), Burundi (44), Côte d'Ivoire (54), Cameroon, (54), Ecuador (15), Gambia (12), Kenya (78), Kuwait (15), Liberia (24), Oman (15), Nepal (64), Paraguay (15), Republic of Ireland (24), Sierra Leone (24) and Sri Lanka (78).

 

[historyfool]

I would tend to agree with you based on gut feeling, but I cant realy come up with a good justification. @historyfool s definition of the "do everything" tank is pretty compelling.

The Panther improved on some of the features (e.g, mobility) and added the ability to compete directly with dedicated heavy tanks, so it is a step towards further general purpose capablities. Overall I find it incredibly hard to draw a hard line, saying this is still a medium tank, this is an MBT: The IV was not designed as universal tank, but developed into one, the T-34 was designed with the idea of at least a universal medium tank, but wasn´t really one at first. But by 42 both started to fill that role. Does that mean the IV isn´t an MBT, but the T-34 is? Or is the Panther the first to reach that stage, as it is capable of fighting heavies? Or does the continued development of heavies in the 50s mean that the first post-war tanks are still medium tanks in concept, not actually main battle tanks? One can argue for each of these points. I tend to go for earlier rather than later, but IMO it is an evolutionary development, not a sudden step.

 

[longtimelurker]

The Panther improved on some of the features (e.g, mobility) and added the ability to compete directly with dedicated heavy tanks, so it is a step towards further general purpose capablities. Overall I find it incredibly hard to draw a hard line, saying this is still a medium tank, this is an MBT: The IV was not designed as universal tank, but developed into one, the T-34 was designed with the idea of at least a universal medium tank, but wasn´t really one at first. But by 42 both started to fill that role. Does that mean the IV isn´t an MBT, but the T-34 is? Or is the Panther the first to reach that stage, as it is capable of fighting heavies? Or does the continued development of heavies in the 50s mean that the first post-war tanks are still medium tanks in concept, not actually main battle tanks? One can argue for each of these points. I tend to go for earlier rather than later, but IMO it is an evolutionary development, not a sudden step.

I was always told that the first "true" MBT was the Centurion

 

[Not James Stockdale]

So the first MBT was the Pz.III ausf. J?

I would probably suggest the Pz III F with the 5 cm gun based on my definitions. Whether the gun is appropriate for an MBT is debatable, but I made my decision based on the role of the Pz III in the Panzer divisions.

I was always told that the first "true" MBT was the Centurion

The early Centurion and Panther are almost identical in terms of gun and armor. Both the Germans and the British still had heavy tanks, so that isn't anything particularly different.

The Panther improved on some of the features (e.g, mobility) and added the ability to compete directly with dedicated heavy tanks, so it is a step towards further general purpose capablities. Overall I find it incredibly hard to draw a hard line, saying this is still a medium tank, this is an MBT: The IV was not designed as universal tank, but developed into one, the T-34 was designed with the idea of at least a universal medium tank, but wasn´t really one at first. But by 42 both started to fill that role. Does that mean the IV isn´t an MBT, but the T-34 is? Or is the Panther the first to reach that stage, as it is capable of fighting heavies? Or does the continued development of heavies in the 50s mean that the first post-war tanks are still medium tanks in concept, not actually main battle tanks? One can argue for each of these points. I tend to go for earlier rather than later, but IMO it is an evolutionary development, not a sudden step.

What I looked at was the combination of the assault and exploitation roles into one vehicle. In the interwar Soviet tank forces, there were T-26 infantry tanks and BT fast tanks, and the A-20 and ultimately T-34 were designed to replace both of those tanks. The British continued to use infantry tanks through WWII, unlike everybody else, so maybe the Cromwell and Comet are not actually MBTs even if they could have been used in the role based on their tactical-technical characteristics.

 

[SealTheRealDeal]

The original Royal Marines Armoured Support Group was formed during the Second World War. The Group consisted of two Armoured Support Regiments, each of two Armoured Support Batteries, plus an independent Armoured Support Battery. Each Battery consisted of four troops, with each troop equipped with four Centaur IV and one Sherman tank, giving a total of 80 Centaur and 20 Sherman tanks in the group,

Following their experiences in the Sarawak and Aden one of the regiments were reformed. Each troop consisted of four FV437 Pathfinder amphibious vehicles, one FV444 Scarab AVR(T). Support battery consisted of three FV431 self propelled anti tank gun and two FV442 mortar carriers. Pathfinders were armed with a single L20A1 machine gun and two L4 machine guns. The F444 Scarab mounted the turret of a Saladin armoured car. The 81mm mortar and the wombat anti-tank gun equipped the support batteries vehicles.

The regiment saw action during the Dhofar Rebellion, participating as part of the peacekeeping operations in Lebanon, Cyprus and Bosnia. All vehicles were upgraded in the 1990’s.

Along with the Australian conversions during the Vietnam War, Vickers developed the Cerberus. Basically the vehicle was an inexpensive tank with an Abbott’s hull with an improved engine, upgraded armour and a tank turret with the infamous L7 tank gun.
View attachment 732782
Export customers were Chile (70), Bahrain (12), Botswana (15), Burundi (44), Côte d'Ivoire (54), Cameroon, (54), Ecuador (15), Gambia (12), Kenya (78), Kuwait (15), Liberia (24), Oman (15), Nepal (64), Paraguay (15), Republic of Ireland (24), Sierra Leone (24) and Sri Lanka (78).

Sounds (functionally) like the VFM 5 came a decade early.

 

[CaptainCalvert]

Somua S35 had decent AT and HE capability, good armour and mobility and must be a strong contender for an early MBT. Give it a 2 man turret and a decent radio and it would have been a great tank. Even as it was, the German army used it in Barbarossa because despite the limitations the 47mm gun and armour were good for the time.
The Vickers 6E copies like T26 (which had decent 45mm AP and HE) almost qualify as pioneers because they weren't specialised in role though the armour wasn't good enough to be true MBTs.

 

[Not James Stockdale]

Somua S35 had decent AT and HE capability, good armour and mobility and must be a strong contender for an early MBT. Give it a 2 man turret and a decent radio and it would have been a great tank. Even as it was, the German army used it in Barbarossa because despite the limitations the 47mm gun and armour were good for the time.

Technically speaking, I would agree, but the French, like the British and Soviets, had a strong split between their infantry and cavalry tanks. Therefore, under French doctrine, it did not combine the assault and exploitation roles. That being said, the existence of the Tiger, Churchill, and KV heavy tanks might indicate that the Panzer III, Panzer IV, Cromwell, Comet, and T-34 were not main battle tanks. Only the M4 Sherman would be an MBT, and only because the US failed to introduce an actual heavy tank. That being said, only the French had different kinds of mechanized or mobile divisions (DLCs, DLMs, and DCRs) equipped with different kinds of tanks.

 

[CaptainCalvert]

I think it's reasonable to have MBTs and also to have specialised breakthrough and lighter tanks for scouting and screening, provided the MBT still does pretty much every other role.
It's interesting to look at organisation as an indicator of whether an MBT would have been useful in that army. Most of the French formations would have worked well with something like the planned Somua S40 as the sole or main tank, plus a few breakthrough tank units. I'd expect the main differences would then be proportion of supporting arms in the different types of unit.
However, a standard all round tank might have led to a more standardised unit structure that could do most jobs well, backed by a few specialist units optimised for breakthrough and light roles.

 

[Not James Stockdale]

I think it's reasonable to have MBTs and also to have specialised breakthrough and lighter tanks for scouting and screening, provided the MBT still does pretty much every other role.
It's interesting to look at organisation as an indicator of whether an MBT would have been useful in that army. Most of the French formations would have worked well with something like the planned Somua S40 as the sole or main tank, plus a few breakthrough tank units. I'd expect the main differences would then be proportion of supporting arms in the different types of unit.
However, a standard all round tank might have led to a more standardised unit structure that could do most jobs well, backed by a few specialist units optimised for breakthrough and light roles.

One of my main goals in this exercise was to redefine the main battle tank in terms of being the predominant rather than universal tank. Even today, there are still reasons to employ tanks other than MBTs, and light tanks never really went away despite the improved mobility of the medium and heavy tanks. The use of specialized breakthrough tanks was readily apparent in the German and Soviet armies, and I have no problem calling the Pz IV and T-34 main battle tanks. The British had a much higher ratio of heavy tanks (Churchills) to medium tanks (Cromwells and Shermans) and also had a tendency to use their medium tanks in different roles in the armored division, so it is more difficult to call the Cromwell a main battle tank. The French used a wide array of tanks of varying sizes in a number of highly specific roles, which makes it even more difficult to identify a primary battle tank in their divisions. As a result, I would say that the S 35 was not a main battle tank.

This does bring up the issue of the early German Panzer Divisions, where Pz IIIs and Pz IVs were mixed with a definite division of labor. In this view, the Germans did not have a main battle tank until the Panzerabteilungen dissolved their escort companies of howitzer-armed Pz IVs and settled on a single combat tank across the Panzer Regiment. That being said, the Panther certainly fits my definition of a main battle tank, and the tanks it directly replaced within the Panzer Divisions, the Pz IV G and before that the Pz III, both meet the technical standards I established.

 

[AJE]

This is my basic conception of main battle tank generations. My general thinking is that, if a given tank is a main battle tank, the tank it replaced was probably also a main battle tank. This means that I will be going all the way back to WWII-era medium tanks. However, to ultimately identify a split between interwar light and medium tanks and what I consider to be main battle tanks, I have to establish some concrete definitions based primarily on the Iron Triangle.

Some of those tanks are similar to the previous generations' heavy tanks (i.e. the M26 is similar to a Tiger 1, a later Centurion is similar to a Tiger II, an IS-3 is similar to a Chieftain- and the Chieftain is similar to a heavy tank in many ways).

Overall I find it incredibly hard to draw a hard line, saying this is still a medium tank, this is an MBT: The IV was not designed as universal tank, but developed into one, the T-34 was designed with the idea of at least a universal medium tank, but wasn´t really one at first. But by 42 both started to fill that role. Does that mean the IV isn´t an MBT, but the T-34 is? Or is the Panther the first to reach that stage, as it is capable of fighting heavies? Or does the continued development of heavies in the 50s mean that the first post-war tanks are still medium tanks in concept, not actually main battle tanks? One can argue for each of these points. I tend to go for earlier rather than later, but IMO it is an evolutionary development, not a sudden step.

The Soviets didn't designate any of their tanks officially as main battle tanks until the T-64, which is when they shut down their heavy tank production.

 

[CaptainCalvert]

Picking a clear candidate and working back to see where you start wondering can be a good approach.
As proposed, the Panther would be a good starting point for defining an MBT. As mentioned the IV G (and probably 76mm Shermans) would be just close enough to count. The 75mm Shermans were used in an MBT-like way but might just fall short. So we have a good candidate, a few marginal ones and a few that don't quite make it. Works for me.