Heavy Metal – The evolution of the US MBT

Today Lee looks at the evolution of the US MBT from immediately post WWII to the IPM1 in Stripes

Introduction

Stripes continues a trend present in Leopards and Volksarmee by offering both a 2nd (M60 Pattton) and a 3rd generation tank (M1 Abrams) for players to use, providing a glimpse at the pace of development from the late 50’s (M60) to the mid 80’s (IPM1).

US tanks design, had a somewhat rocky path post WWII, being caught up in institutional dithering on the worth of the tank, changing military situations and the constant failure of combined NATO projects such as the MBT-70.  This article takes a look at where (very) late war Flames of War left off, through to where Stripes concludes.

Pershings

The US ended WWII with two medium tanks forming the majority of its inventory; the M4 Sherman and the M26 Pershing, initially classed as a ‘Heavy’ tank.  The M4 Sherman had been the workhorse of the US Army and, despite many myths to the contrary, had acquitted its self well on the major battlefields of WWII.  But, despite uparmouring and up-gunning to form such variants as the Firefly or M4A3E8, the Sherman struggled to take on Panthers and Tiger IIs in one on one battle.

All of this would have been well enough if humanity had decided that WWII was definitely the war to end all wars, but the carving up of Europe at Yalta led to the US and its allies staring down a Soviet sphere that was keen to make sure its IS-3 task were visible at the victory parades.  The M4 had clearly reached its limits (Israel would disagree and continue to extract more firepower out of the M4 chassis in the form of its various upgunned variants in the Six Day War) and so the US turned to the late-comer, the M26.

Compared to its stablemate, the M26 was a low-slung, well armoured and well-armoured power house.  Sporting a 90mm main gun that could rival the long 75mm of the Panther, the M26 was initially labelled a heavy tank but eventually designated a “medium” tank.  Interestingly, neither stabilisers or ammo protection appeared as features in the Pershing despite being standard in the Sherman by this point in the war for late pattern models.  These features would not make a re-appearance in an American tank for quite some time!

Having bloodied itself in the dying months of the war in Europe and the Pacific, it would see action again in South Korea.  Three whole M26 tanks (!) were sent from Tokyo to support the troops in field (up to then only supported by Chaffee – against T-34/85 that worked about as well as one could expect…) but suffered from poor mechanical reliability due to basically being reconstituted depot units.  More would be sent (backed up by M4A3E8 due to insufficient numbers) and would quickly prove their worth; being able to easily penetrate clean through the T-34/85 with HVAP ammo whilst being near invulnerable in return.  Its greatest issue was the terrain; the Ford V8 inherited from the M4A3 being overworked in the heavy weight M26.  Still, the M26 made a considerable impact and showed the worth of the basic design.

Battlefront example M26

 

 

The M26 has so far only appeared in the WWII game, boasting “standard tank” mobility, a Front Armour of 10, a side armour of 6 and an AT14 main gun, but no stabiliser or protected ammo!

Pattons

M46 – The first Patton

The M26’s mobility and reliability shortfalls were to be corrected in an upgrade M26E2 version but the number of changes became great enough that it was re-designated as a new tank; the M46 Patton.  Its doubtful anyone at the time appreciated how long the Patton line would stretch from these humble beginnings!  The M46 took the M26 hull and gave it a new V12 engine, new transmission and a new 90mm gun.  Over 800 M26 were upgrade to the M46 standard, a further 400 would be upgraded to a slightly improved M46A1 standard, and these would serve in the Korean war from mid 1950 onwards.  Ultimately, the M46 had a short life, serving as an interim model to tide the US and allied forces over until a new model arrived.

When your nigh-invulnerable, its hard not to get a little cocky

M47 – Pattons. Pattons everwhere!

The original intention had been to replace the M46 with an entirely new tank, completely divorced from the M26 lineage.  This new tank, then a prototype designated the T42, was encountering a number of issues and the decision was taken, in light of lessons from the Korean War, to take its turret and marry it to the M46 hull, forming the M47 Patton tank.  The “needle-nosed” turret greatly improved the ballistic protection of the turret and incorporated a stereoscopic range finder to improve first hit probability with the 90mm main gun.

Over 8000 M47 would be produced from 1951-53, serving with over twenty countries and fighting in such wars as the Indo-Pakistani, Iran-Iraq and Croatian Independence wars.  Despite this combat history, the M47 has yet to appear in any Battlefront game!

M48 – Patton vs Charlie

Having now had two “interim” models, the US Army sought a long term “standardised model” to serve as its Main Battle Tank, kicking off in 1951.  The new tank would improve the hull protection shaping by deleting the (largely useless) assistant driver MG position, introduce a new hemispherical turret for better ballistic protection and a new 90mm gun, the M41 – with a distintive T shaped muzzle break.  The type had a number of variants.  The first, the A1, introduced a new cupola that placed the commander’s .50 under cover.  This came at a cost as it increased the overall height of the tank (shades of the M3 Lee) as well as making for a cramped fighting space.  The A1 was quickly followed by the A2 which improved the range finder, engine cooling and suspension but did little to fix issues with the gasoline powerplant’s range and reliability.  It would be the M48A1 and A2 that saw service in the Six Days War with both the Israeli and Jordanian forces.  The Israelis’ in particular noted the gasoline’s powerplant susceptibility to catching fire on being hit.

Jersey’s Jordanian M48 

The M48 went Diesel with the M48A3, introducing a twin turbo Diesel engine and a new transmission.  The driver gained an IR sight and the commander gained improved all round visibility by raising the cupola and adding extra vision blocks.  A night fighting capability was provided in the form of distinctive over barrel white light and infra red searchlights.
The M48A3 was sent to fight in Vietnam and proved a useful capability in that war, being relatively proof against the enemies booby traps and mines, and providing valuable for support to troops under fire.  More than one fire base was saved by the timely arrival of a platoon of M48 and they even managed a few tank on tank battles, albeit against light PT-76 scout tanks.  After the US pulled out, the South Vietnamese would replace some of their M41 Bulldog with M48 and they would see use versus NVA T-54/55, slowing the adavnce but quickly suffering from a lack of spares and supplies.  One tank also became the first to be killed by the “Sagger” ATGW.  It would not be the last M48 in the world to suffer that fate.

The M48 (along with the M47) would also see action in the Indian Pakistan wars, being roughly on-par with the Centurions tanks operated by the Indians but generally suffering against Indian AT weapons.

Battlefront example M48A3

The M48 in Tour of Duty and Fate of a Nations boasts “standard tank” mobility, a Front armour of 12, side armour 8 and an AT16 main gun.  It has IR options but still no niceties like protected ammo or stabilisers!  The Magach 3 introduces the L7 105mm gun, boosting AT to 18!

The final version of note was the M48A5.  This was a mid-seventies upgrade to bring the M48 to M60 standards and reflected some practices introduced by the Israelis pre and post Six Days War, namely a reduced height cupola that deleted the internal machine gun and a variant of the British L7 105mm tank gun to increase lethality.  The powerplant and FCS also borrowed heavily from that present in the M60A1.  The A5 type was used by the US, plus export users such as Greece (Turkish M48A1 were upgraded to a standard similar to the M60A3), Spain, Portugal and Norway.  If Team Yankee expands to either the Northern or Southern theatres then we could possibly expect to see the type in Team Yankee.

Over 12,000 M48 would be built, equipping various existing and new Patton users worldwide.

 

M60 – The Next Generation

The 1956 Hungarian Revolution was a failure for the Hungarian people but an intelligence coup for the West as, allegedly, a T-54 was parked on the lawn of the British Embassy.  Whilst the Foreign Office no doubt wrote a stern letter about “keep off the grass” signs, the T-54 was whisked off (stories always gloss over that bit – surely that must have been an interesting tale!) and analysed.  The initial analysis was sobering, the T-54 would withstand all but the most optimum hits from a British 20pdr or US 90mm and its own 100mm would make short work of the Centurion and M48 in return.

These revelations kicked off the “2nd generation” of tank design.  The British would create the L7 105mm that would go on to equip most 2nd generation NATO tanks, but would itself look beyond that to a new 2-part 120mm rifled gun in a low slung, well armoured chassis to form the Chieftain (first prototypes arriving for troop trails in 1959).  The Soviets, not ones to rest on their laurels, would round out the 1st generation with the T-62 and its deadly, if cumbersome, high velocity 115mm gun, before proceeding to the T-64.  The T-64 combined new armour with a compact hull and an auto-loading 125mm gun – easily matching if not surpassing the Chieftain.  An early 115mm armed variant arrived in 1964.

Whilst all this was going the US did some revolutionary!

Well, no, it didn’t.  Once again a high-tech T series tank – the T95 – failed to deliver so the Patton chassis came to the rescue. It was eventually agreed, after testing every possible entirely US solution, that the British 105mm was quite good and slapped it on an improved M48 chassis.  As with the 105mm armed Centurion and the 115mm T-62, the US realised that the need for Heavy Tanks was over and embraced the “Main Battle Tank” concept.

The M60 hull was superficially similar to the M48 but made the switch to a more efficient Diesel powerplant.  The turret looked superficially similar to the M48 but incorporated the M68 105mm main gun (combining a British barrel and ammo with a US breech design).  The stereoscopic range finder of the M48 was further improved and worked well with the longed-legged M68 to improve first round hit probability.  Whilst not as revolutionary as the Chieftain or T-64, it beat its peers to service and its simple design proved a boon compared to the novel but troubled power-plants adopted by the other two.

The M48-esque turret was quickly replaced by one adopted from the abandoned T95 (the US sure do like re-using T series turrets!  Continuing a tradition started with the 76mm Sherman); a new needlepoint turret that deceased the frontal cross section whilst increasing armour protection.  This became the M60A1 and was intended to serve until a new high-tech replacement came along in the form of the Germano-US MBT-70.

The M60A1 has a front armour of 15 and a side armour of 8.  The stabilised main gun has a ROF2, moving or halted, but lacks a laser range finder.  The stereoscopic range finder grants it “accurate” though (ignore range penalty when halted).

When this didn’t occur (again), the M60 benefited from the technology that was already developed.  The improved Shillelagh missile/gun system was mounted into a somewhat futuristic turret to form the M60A2 version of the tank.  Sadly the Shillelagh was no better in the M60 than it was in the Sheridan or MBT-70 so the tanks had a short life before being upgraded into more useful variants.  However, some of the technologies developed would go on to greater things…

The M60A2 is taller than the Chieftain, in part due to its cupola but also the taller hull.  But the narrow turret of the M60A2 can be appreciated here.

In the meantime, with a new tank on the horizon in the form of the XM-1, the M60A3 was created to incorporate a whole slew of new technologies into the existing M60A1.  The main output of this was an improved stabiliser, smoke dischargers (surprisingly) and a laser range finder.  The M60A3 also received a thermal sight which, by dint of being developed later, was actually better than the one in the XM-1.

The M60A3 still has a front armour of 15 and a side armour of 8.  But the gun now has a laser range finder and a thermal sensor.

The tank was an export success, seeing action in the IDF in Yon Kippur and with the Iranians in the Iran-Iraq war.  With the US, only the M60A1 saw combat, serving the USMC in the Gulf War, albeit equipped with Explosive Reactive Armour.  The M60A3 left US Army service (in a training role) in 2005, having been replaced by the eventual output of the XM-1 competition.

Talking of the XM-1…

M-1 Abrams (thank god it finally has a name that isn’t bloody Patton)

If the MBT-70 was a failure, it at least gave the German and US design teams some useful ideas of what a third generation tank should have.  The Germans would eventually come up with the Leopard 2, whilst the US would create the XM-1 competition.  This pitted General Motors versus Chrysler (plus an “austere” version of the Leopard 2) in a “drive-off”.  The specification ditched expensive and unreliable gun missiles in favour of the tried and trusted M68.  Both teams had to re-design their submissions to incorporate the ground breaking, and highly secret, Chobham armor from the UK.

Eventually, Chrysler was declared the winner on the basis of superior performance.  The winning design incorporated a gas turbine powerplant in place of the normal piston based internal combustion engines, providing a huge amount of horsepower at the cost of fuel expenditure and lingering concerns of the ability of the engine to operate in dirty field conditions (although gas turbines have a lot less moving parts so reliability is usually pretty good).  The power could be put to good use as the gun was married with an advanced multi-axis stabiliser and computerised fire control system with muzzle reference system and cross wind sensors to ensure a first hit potential even whilst moving at speed.
The design also incorporated a thermal sight for the gunner and separated ammo storage from the crew compartment via an armoured door and a compartment that would direct any cook-off of the ammo via a pair of blow-off panels on the roof.

The M1 features a front armour of 18 and a side armour of 8 (16 versus HEAT thanks to the “Chobham” rule).  The 105mm gun has an Anti-Tank of 20 (the long rod DU round improving this over the AT19 of the Leopard 1 example).  Its real differentiator is mobility – it can shoot twice whilst moving a massive 14″ and can dash up to 28″ over cross-country.  

Winner Dave’s  M1 Abrams platoon

The design appeared in the field as the M1 in 1980, quickly appearing in the European theatre.  Service use noted that the tank suffered from a lack of stowage and issues with access on the tracks.  The US had also settled on its next tank gun, the Rhinemetal 120mm smoothbore as used on the Leopard 2 (so, British armour, German gun, Belgian co-ax and AA MG…).  A new turret was required to house the larger gun and its larger ammo, also increasing the armour protection.

Rather than wait for the 120mm gun, an interim model was created that used the larger turret and various powerplant and electronics tweaks proposed for the M1A1 with the 105mm gun.  This was dubbed the Interim-Production M1, or IPM1 for short, and examples started appearing in 1984.  Being an interim model ‘only’ 894  would be produced(!).  Major visual differences to the M1 include:

  • Longer turret (overhanging the forward hull more though it can be difficult to spot)
  • Rear turret bustle rack (although some original M1 had improvised rear racks added)
  • Deletion of the drive sprocket retainer ring
  • New cut back bazooka plate to improve access to the sprocket

The IPM1 grants the M1 stats above a healthy Front Armour 19 and Side Armour 10, making it near unkillable versus the BMP-2.  Not bad for a 1pt upgrade!

The IPM1 would be sent to Saudi Arabia in the build up to the Gulf war but was replaced by the M1A1 before Desert Shield switched to Desert Storm.  The M1A1 would then go onto carve a name for itself against the variety of Iraqi armour arrayed against it.  The M1A1 was eventually uparmoured with additional depleted uranium armour (its fine…) and was eventually partly-replaced by the M1A2 which standardised the additional armour and added such electronic goodies as 2nd gen FLIR and an independent FLIR for the tank commander.  But all of that is outside of the scope of the Team Yankee game.

(Although the inclusion of an M1A1 CITV cover plate and 120mm gun barrel suggests that a “for now” should be added…)

Coming to a table top near you? Near-future Team Yankee anyone?  A plastic T14 Amarta would look pretty sweet too…

 

Category: 'NAMArab-Israeli WarFlames of WarRamblingStripesTeam YankeeUSA

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2 comments

  1. Please note, the Abrams’ “sophisticated fire control system” wasn’t that sophisticated. The M68 gun was (is) only stabilized in elevation, as it was slaved to the gunner’s sight head mirror, which was the only stabilized component and serviced the optical and thermal sights. The traverse rate of the turret allowed easy tracking in azimuth and no stabilization was required. The ballistic computer and associated sensors did all the work. Lase on the target and the reticle moves to the correct position. Re-lay the reticle on the target and fire. That simple. Just “Lase and Blaze”. First round hit probability was (is) over 90% at normal combat ranges for the average gunner. I was involved in the testing of the M1s at Lima during the initial production and coordinated fire control testing/performance. The M60A3 had a similar fire control system and had similar first round hit probabilities. There are those who say that the M60A3 had a better fire control system than the Abrams, but they were comparable in their lethality. Technically they should be treated the same in the rules.

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Article by: Lee

Wargaming since Rogue Trader in 1990; I made the move to Flames in 2006 and have been with it ever since! I play at the Brighton Warlords most weeks.