Cadillac Gage Stingray

     Notes: The Stingray is a relatively light tank originally developed as a private venture by Cadillac Gage.  Cadillac Gage was primarily hoping for sales to countries who either didn’t have the funds or the need for a large, powerful main battle tank. They also had an outside hope that the US Army would also be interested, as in 1988 when the Stingray was put on the market, the US Army was looking for a replacement for the M551 Sheridan light tank in the 82^nd Airborne Division and possibly other light units.  To this date, only the Thai Army operates the Stingray, but several countries have expressed some interest, including Taiwan, South Korea, Pakistan, and some African nations.

     The layout of the Stingray is essentially conventional, with a driver in the center hull front, and three crewmen in the turret in the usual places.  Standard armor protection is nothing to write home about, but a combination of clever sloping and high-strength steel gives the Stingray more protection than one might think given the Stingray’s light weight.  The Stingray can be equipped with lugs for ERA on the glacis, hull sides, and the turret sides, and several types of appliqué armor (more on that later).

The Stingray

     Sometimes called the Stingray I, this is the original version of the Stingray, first introduced in 1988.  This is the version that the Thai Army uses; they bought a total of 108.  As said above, the layout is conventional; the driver is at the hull center front behind the glacis.  The driver’s hatch can be locked partially open to give the driver better vision and some extra ventilation, or fully open for entry and exit.  The driver normally enters and exits his station through the turret, but if the main gun is traversed away from his hatch, he can easily enter and exit through his own hatch.  The driver has three large vision blocks, giving him a 120-degree field of view to the front and partially to the sides.  The center vision block can be removed and replaced with one that incorporates a night vision periscope.  The driver’s seat is adjustable and is said to be more comfortable than the average tank driver’s seat, reducing fatigue.  The driver has an oval steering wheel rather than a yoke or laterals, and a conventional brake and accelerator. On either side of his seat are racks for 14 rounds of main gun ammunition; these can be covered by Kevlar blankets acting as a spall liner, with a third blanket separating the driver from the turret.  Though not accessible from inside the vehicle, there are storage compartments for equipment and crew gear on either side of the glacis, above the tracks.

     Turret crew positioning is conventional, with the commander on the right with a hatch in the roof, the loader’s hatch on the left, and the gunner below and to the front of the commander.  The commander has a day/night sight and can tap into the gunner’s sights; he also has an override for the main gun.  He does not have a cupola, but has a pintle mount to the right front of his hatch that can mount an M2HB, M240 machinegun, or other compatible weapons.  The gunner has a roof-mounted M36E1 sight that is normally a day/night sight with magnification and a ballistic computer, but an enhanced version of the same system (the M36E1 SIRE system) that incorporates a thermal imager and a laser rangefinder can be installed instead.  The loader has a single wide vision block in front of his hatch.  Note that I have referred to the Stingray with improved sights and lighter tracks as the “Enhanced” model below; this is not actually any sort of official designation by Cadillac Gage.

     The primary armament of the Stingray is a Royal Ordnance 105mm LRF (Low Recoil Forces) rifled gun; this is a modified version of the L-7A3 with substantial recoil buffering and a large muzzle brake.  The coaxial armament is an M240C machinegun, though this can be replaced with many other 7.62mm NATO-firing machineguns upon request.  On either side of the turret are mounted a quartet of smoke grenade launchers, and eight more smoke grenades are carried inside the vehicle as reloads.  Gun stabilization is excellent, as it is a modified form of the stabilization system found on the M1 Abrams.  The gun controls and the ballistic computer are modified versions of those found on the M60A3.

     The Stingray’s suspension is based on that of the M109 self-propelled howitzer, with roadwheels of the same type as those on the M41 light tank.  Initial production Stingrays used conventional-type tracks 38 centimeters wide, but a new type has been devised that are both stronger and much lighter, making the Stingray a ton lighter.  The engine is a Detroit Diesel 8V-92TA turbocharged diesel developing 535 horsepower, and the transmission is automatic and the same as used in the M109 SP howitzer.  Access to the power pack is designed to simplify maintenance and if necessary, replacement as one unit.

The Stingray II

     The Stingray II was introduced in 1996 as an evolutionary update to the Stingray.  It was developed for the export market, but has seen no takers as of yet.  Like the Stingray, it uses many systems from other successful vehicles to save time and costs, and is a surprisingly effective light tank design.

     The layout of the Stingray II is basically identical to the Stingray, with the crewmembers in the same place as in the Stingray.  The gunner, however, is equipped with the same fire control system as on the M1A1 Abrams.  The gunner gets information automatically from a ballistic computer and a laser rangefinder, and the sights include an image intensifier and a thermal imager, with a 6.2x telescopic gunsight as a backup.  Gun stabilization is electro-hydraulic as standard, but can be upgraded to an all-electric stabilization according to buyer requirements.  The meteorological sensor is mounted on mast approximately 60 centimeters tall at the rear of the turret; this provides very accurate information about wind, temperature, and other weather conditions that would affect a shot, but may be a bit vulnerable in combat.

     The commander’s position is almost the same as on the Stingray, but the commander has a 6.2x periscope along with an image intensifier.  The commander also has a small monitor linked to the gunner’s thermal imager, and auxiliary controls for the main gun and coaxial machinegun.  The driver’s position is essentially identical to the Stingray.

     The suspension of the Stingray II is beefed up to handle the increased weight.  The engine is an uprated version of the Stingray’s engine, developing 550 horsepower, and matched with a modified form of the Stingray’s transmission.  Appliqué armor may also be fitted to the Stingray II, in the same manner as the Stingray.  The Stingray’s armor is made from higher-strength steel, called 2001 steel by Cadillac Gage.

Stingray Appliqué Armor

     Several add-on armor packages are available for the Stingray.  ERA has already been mentioned, but passive add-on armor also exists, ranging from simple bolt-on plates to ceramic/metal sandwich armor and varying levels of protection similar in concept to that of the M8 Buford AGS.

     Bolt-on appliqué consists of added steel on different faces.  This is a generalization, but such kits add armor panels to the glacis, turret front, turret sides, and hull sides, and do increase weight.  Spaced armor plates also exist; they add points to the same faces.  Ceramic sandwich appliqué armor also adds to the same faces, but is the equivalent of composite armor or spaced armor, depending upon the armor face.  The graduated M8 AGS-type add-on armor packages are referred to below in the same way as the M8 entry: Level 1, Level 2, and Level 3.  Level 1 is the base Stingray; Level 2 is basically bolt-on armor panels with some armor spacing, and Level 3 builds on level 2.

     Twilight 2000 Notes: In 1997 in the Twilight 2000 timeline, as Cadillac Gage’s production facilities escaped destruction in the November Nuclear Strikes, the US Army and Marines requested that the remaining Stingray production be directed to the US military, and production of these vehicles continued for several years, with the Stingray being type-standardized as M9 light tank (or M9E1 for the enhanced version).  Before that, several countries bought the Stingray, including Thailand, Taiwan, and a number of countries in Africa and Central and South America. 

     The composite appliqué armor was quite rare on US Stingrays, and nonexistent on other countries’ Stingrays; the same goes for the M8 AGS-type graduated armor packages, though it was a bit more common than composite appliqué on US Stingrays.  Bolt-on appliqué was very common on all countries’ Stingrays.

     Stingray II production began earlier in the Twilight 2000 timeline; the first production models rolled out in 1994.  Taiwan immediately bought 100, and they were also bought by Thailand, South Korea, and Turkey, as being given to China in a sort of Lend-Lease program.  Most of these were base Stingray IIs, though some were equipped with simple appliqué armor.  Again, Cadillac Gage was hoping for domestic sales, and their chance came when the United States went to war.  Due to the critical need for the M1 Abrams series, some newly formed units were facing lengthy periods before their units could be equipped.  Several newly formed armored units adopted the Stingray II (and the Stingray), though few Stingray IIs were shipped out before the November nuclear strikes.  Those vehicles that shipped were equipped with ERA to increase their survivability; most also had simple appliqué armor panels, with perhaps 25% having AGS-type appliqué and about 10% having composite appliqué.  It appears, however, that most Stingray IIs ended up in units in the Texas National Guard’s 49^th AD and other places in the Southwest, as they were rushed to the US-Mexican border when war broke out between the two countries.

Chrysler M47 Patton

     Notes:  In many ways an improved version of the M46, the M47 was an experimental tank (called the T-42) at the beginning of the Korean War.  However, despite the fact that the T-42 had not completed trials and many generals felt it was underpowered, it was immediately allotted the designation “M47” and ordered into low-rate initial production; the generals also felt that the M46 was already obsolete.  Production began in mid-1951 at the Detroit Arsenal, with Chrysler taking over the facility in mid-1952.  Production for US forces continued only until November 1953; at that point, efforts were shifted to the T-48 prototypes, which eventually became the M48 Patton tank.  Small quantities of the M47 are used by Greece, Italy, Pakistan, Somalia, South Korea, Turkey, and the former Yugoslavia, but only Spain and Iran still use the M47 in any large numbers (as a tank; large numbers have been converted to ARVs). 

     The M47 used a modified version of the M46’s hull. (The original design called for a new hull as well, but the expedient of using a modified M46 hull was done to hurry the M47 into production.)  The slope of the glacis was increased to 60 degrees, though the thickness of the armor remained the same.  The ventilation blower in the front hull was removed to improve the armor silhouette, and replaced with one in the turret bustle.  The turret ring was enlarged to fit the T-42’s larger turret.  The bow machinegunner/radio operator’s position was retained.  The M46 had infrared headlights, for use with the then-new night vision equipment available for tanks.

     The turret of the M47 was a new design; it was a cast circular turret has a distinctive rear bustle extending from the rear of the turret.  The turret had a low commander’s cupola with a ring of vision blocks, and next to it was an M2HB mounted on a pedestal mount.  The commander also had a periscope for vision while buttoned up or longer-range vision.  Primary armament was an M36 90mm gun, with an M1919A4E1 as a coaxial machinegun.  A further M1919A4E1 was used at the bow machinegunner’s position.  The gunner was equipped with a coincidence rangefinder for aiming. After testing, the speed of turret traverse was increased and gun stabilization improved to minimize gun bouncing when the turret was traversed; however, the main gun was never fully stabilized as the electric stabilization never got perfected due to the war emergency.  Above the main gun, a large searchlight was mounted.

     The suspension was, like the rest of the hull, a modified form of the M46’s suspension.  The second and fourth return rollers were eliminated from the design after testing at Aberdeen Proving Ground, and the engine was changed to a 704 hp AV-1790-5B gasoline engine (with an emergency horsepower rating of 810 hp).  The driver’s position was slightly better ergonomically than the M46A1, but the bow machinegunner had no auxiliary controls.

     Though the US military was no longer using the M47 by 1969, BMY came out with an upgrade kit for the M47 for allies still using the M47; this was called the M47M.  The modifications used as many components of the M60A1 in order to reduce (real-world) costs.  The primary upgrade was the replacement of the power pack with one based on the AVDS-1790-2A 750 hp diesel engine and an appropriate transmission, with the whole being integrated for easier servicing.  The rear of the hull deck and the grill doors were identical to those of the M60A1, and the last pair of roadwheels were moved back about 8 cm to properly seat the engine.  The M47’s shock absorbers were replaced with those of the original M60, and the track tension idlers were removed.  Interior rearrangement as well as the smaller engine size allowed for a phenomenal increase in fuel tankage, and along with the greater fuel economy, caused the range of the M47M to rise dramatically.  The bow machinegunner’s position was removed, the port plated over, and the space used for ammunition storage.  Further rearrangement allowed quicker access to the main gun rounds and the carriage of more modern rounds.  The main gun stabilization system was a modified form of that used on the M60A1.  The coaxial machinegun was replaced with an M219 or a MAG.

     Since then, several other countries have developed or fielded other upgraded M47 designs.  Most are no longer in use, but they will be found under the appropriate national listings.

     Twilight 2000 Notes: As the war emergency intensified, many M47’s were fielded in the Twilight 2000 timeline, primarily in the Middle East, but also in Europe to an extent.  Most of these were upgraded M47s such as the M47M, or as found under national listings.

Chrysler M48 Patton

     Notes: The predecessor of the M48, the M47, was always considered to be a stopgap, a quick solution to the problem of the T-34 tanks used by the Chinese Army in the Korean War.  Knowing this, the M48 Patton began development almost parallel with the M47.  The M48 was to be a smaller, lighter version of the failed experimental heavy tank, the T-43, a medium tank instead of a heavy tank.  Design work on the M48 began in late 1950.  The M48 was the only version of the M47/M48/M60 series to be officially called the Patton, though the M47 was informally called the Patton as well.

The M48

     The M48 features an elliptical turret with virtually no shot traps and mildly-sloping armor on the front and sides.  The hull was also essentially an elliptical shape, with a heavily-sloped glacis.  As much as possible, the M48 is built with one-piece steel castings, including almost the entire turret and most of the lower hull.  The turret uses a wide turret ring, contributing to the sloping of the turret sides and contributing to the lack of shot traps.  It also allowed for a larger turret; it was projected that the M48 would be given a heavier main gun in the future, and the large turret gave the M48 room for expansion.

     The original M48 began service in mid-1953.  Production had started about eight months earlier.  Early issue was restricted to training issue in the US, as much of the fire-control equipment the Army had required was still under development, and various bugs in the M48 were still being ironed out.  Actual full-service issue did not occur until over a year later.  When finalized, the M48 had what was, for that time, a state-of-the-art fire control system, including night vision, a primitive ballistic computer (with about as much computing power as one could find in a digital watch in a dollar store these days), and a coincidence rangefinder with semiautomatic operation.  The M48 has a ballistic drive for the main gun that could automatically set the proper elevation and lead for the gun, once the range was determined by the commander or gunner and inputted into the ballistic computer.  The ballistic computer essentially tied the entire system together, and the gunner merely had to put the crosshairs on the target.  Indirect fire was also possible with this system.  Gun stabilization was provided by a new electric system designed by IBM.

     The primary armament of the M48 was the 90mm M41, an update of the M47’s 90mm M36 gun.  The M41 was tipped with a cylindrical blast deflector, and featured a quick-change gun tube.  Originally, the M48 was to have an M2HB ranging machinegun to the left of the main gun and an M1919A4 to the right as a coaxial; due to the advanced fire control system, the ranging machinegun was felt to be obsolete and it was deleted from production models. 

     The commander’s cupola used an M2HB that was mounted externally and capable of remote-control operation from inside a buttoned-up cupola; unfortunately, the commander had to come almost completely out of the cupola to reload the M2HB.  The cupola itself was surrounded with vision blocks giving a field of vision to all directions except directly to the rear (where the mount for the M2HB was attached).  The cupola also had periscope and a separate coincidence rangefinder.  The turret had a small bustle rack at the rear, and bars on the sides for the carriage of crew gear and other cargo.  Brackets on each side of the turret towards the rear allowed for the attachment of a pair of spare fuel cans or water cans.

     The original engine was an AV-1790-5B gasoline engine – the same as in the M47.  This was quickly replaced with an improved model, the AV-1790-7, and then the AV-1790-7B; all three engines developed 704 horsepower, but unfortunately meant the M48 had a ravenous appetite for fuel. The suspension was considerably beefed-up over the M47, with a more comfortable ride and improved off-road performance.  The bow machinegunner’s position was eliminated – technology made his primary job, that of radio operator, unnecessary.  The engine deck was designed to partially suppress heat emissions, as battlefield IR viewers were rapidly becoming more prevalent at the time.  The driver’s position was an improved form of the M47’s position, though consistent complaints were heard about the small size of the driver’s hatch.  (It was made small since it was located in the center front of the vehicle, under the main gun.)  The hull floor had two escape hatches, one for the driver, and one for everyone else.  IR headlights were mounted on the glacis.  Two crew heaters – one for the driver’s compartment, and one for the turret – increased crew comfort.

The M48A1

     The M48A1 fixed a number of problems with the M48, but perhaps the primary change was the commander’s cupola.  The commander’s machinegun was moved inside the new M1 cupola, and could therefore be fired and reloaded from under armor.  The commander’s rangefinder was retained and made sort of a coaxial to the commander’s machinegun.  Vision blocks were mounted in a 180-degree arc at the rear of the cupola, a gunsight for the commander’s machinegun at the front, and a periscope atop the cupola to the rear of the machinegun mount.  The problem with the M1 cupola was its cramped confines, giving the commander barely enough room to operate his weapon or use the periscope or rangefinder even with the hatch open.

     Another change was an interim solution for the M48’s ravenous appetite for fuel, and it seems straight out of Soviet doctrine.  The M48A1 could be fitted with an optional mount for four 55-gallon (208-liter) drums of gasoline.  These were standard 55-gallon drums of thin steel – I don’t think I need to tell you about the fire hazard if they get hit by enemy fire, and because of this, the extra fuel drums were not authorized for use in combat.  These drums could be jettisoned as a group from inside the M48A1.  The engine itself was replaced by the AVI-1790-8, a version of the AV-1790 series which had rearranged engine cooling and oil tanks, as well as the addition of a supercharger and metered fuel intake.  This slightly increased fuel efficiency.  A new transmission was also fitted that was more efficient, simpler in design, and less expensive to produce.

     The main gun’s blast deflector was replaced with a T-shaped model, more efficient as a blast deflector and also functioning as a muzzle brake.  The too-small driver’s hatch was enlarged, and the compartment rearranged to somewhat alleviate its cramped confines.  As the M48 was primarily issued to units in the US, the M48A1s were generally the first M48s issued to US units overseas, particularly in Europe.

The M48A2

     Despite the improvements of the M48A1, it was realized almost immediately that more could be done, particularly in the area of operational range.  The change to the AVI-1790-8 engine, which was much smaller than previous engines, along with the more efficient transmission, meant that there was more internal room for fuel tanks, something not exploited on the M48A1.  In addition, the extra room and different form of the engine (along with some new ideas) meant that IR suppression could be further increased.  The air cleaners were also relocated, making them more accessible and easier to maintain.

     The suspension was almost completely changed; the M48 and M48A1 had consistent problems with suspension breakdowns, particularly in the compensating idler spindles.  These were beefed up considerably (and a kit was devised to apply this modification to M48s and M48A1s).  The hull itself was also modified to provide more room for the bearings of the spindles.  The front roadwheels were given double bump springs.  The second and fourth return rollers on each side were deleted.  Friction snubbers replaced the hydraulic shock absorbers on the two front pairs of roadwheels and the rear roadwheels.  While the snubbers had a much longer lifespan, they also gave the M48A2 a rougher ride, and this got worse the faster the M48A2 traveled.

     The driver’s position was further improved.  The steering yoke was replaced with one that was wider, giving the driver a bit more leverage.  The transmission shift controls were removed from the steering yoke and moved to the floor.  The pair of crew heaters were replaced by a single heater, with ducting going to the driver’s compartment.

     Further improvements led to the M48A2C. The turret control system was replaced with a hydraulic system that gave the crew more precise control over rotation speed and degree of turning.  The new hydraulic motor was also smaller, required less maintenance, and generated less heat.  Similar improvements were made to the rotation mechanism of the commander’s cupola.  A stereoscopic rangefinder replaced the coincidence rangefinder (an “improvement” which proved to be quite troublesome as time went by), an improved ballistic drive was also fitted that took into account the temperature outside the tank and its effect on the ballistics of the fired rounds.  The M48A2’s gunnery controls and ballistic computer was switched to the metric system.  The main gun was fitted with a larger-capacity bore evacuator.  The track tension idlers were made unnecessary by track improvements and were removed.  All M48A1s were modified to the M48A2C standard.  The coaxial machinegun was replaced with the M37, a version of the M1919A4 specifically designed to be a coaxial machinegun.  This version had spade grips and could feed from the left or right side of the gun (though not both at once).

     The M48A2 and A2C became the most-produced M48 variant.

The M48A3

     The M48A3 variant was designed in response to intelligence reports about the capabilities of the Soviet T-55 tanks, with their 100mm guns and heavier armor.  The M60 was not going to be produced in large enough number to replace the M48 for a few more years, so the M48A3 was to fill the “tank gap.”  Most M48A3s were upgraded M48A2Cs, M48A2s and M48A1s, but some were new production.

     The changes from the M48A2C almost resulted in a new tank itself.  Many of the improvements were done by using components that were also used on the M60.  The engine was replaced by an AVDS-1790-2 diesel engine along with an appropriate transmission.  The coaxial machinegun was replaced by the M73 machinegun.  The situation with the cramped M1 cupola was partially alleviated by putting the cupola on a riser.  The fuel tankage was further increased, as the new engine was even more compact then the M48A2s engine.  The two return rollers which had been deleted were put back again in response to feedback from tank crews in Vietnam.  The air filter boxes were moved to the rear mudguards.  Other feedback-related improvements included faster-acting brakes, an improved driver control linkage, an inflatable turret ring seal for weatherproofing, and screening for the bustle rack.  Some improvements were carried out to the fire control system, including replacement of the stereoscopic rangefinder, upgrading of the ballistic computer, and some automation of the fire control process.  A large white-light searchlight was mounted above the main gun.

     The M48A3 became the most common variant actually used in combat; it was the primary tank used by the US Army, Marines, and South Vietnamese Army in the Vietnam War, and the Israelis used them extensively in the 1967 war, including some modified types with heavier armament and appliqué armor.  In Vietnam, sometimes an extra light machinegun was mounted atop the commander’s cupola or at the loader’s hatch (or both); sometimes, the commander’s machinegun itself was removed from its mounting and replaced by an M2HB on a pintle mount atop the cupola.  Branch and wire cutting devices would be mounted on the turret.  Extra track sections were often welded to the sides of the turret and the glacis to provide improvised appliqué armor; M48s also often became heavily sandbagged on the turret and hull.

The M48A4

     The M48A4 was a possibly interesting idea that was never actually deployed, but is interesting enough that I couldn’t resist.  When the M60A2 proved to be a failure, many in the Pentagon felt that the M60A2’s firepower package was good enough that it merited further study; if it could be improved, it might still be a viable option as sort of a tank destroyer/fire support vehicle.  To this end, six M60A2 turrets with improved systems were mounted on M48A3 hulls.  Though the combination worked at least as well as the M60A2, and in fact the systems weren’t quite as nightmarish from a maintenance standpoint, the fact remained that the M60A2’s firepower package was simply unnecessary; the M48A3 itself was a better tank than the M48A4, and there were other fire support options in the inventory that made the M48A4 superfluous for that purpose.  After less than a year of testing, the idea was dropped.

The M48A5

     The M48A5 was the final major US upgrade for the M48 series.  The US found themselves in a curious situation in the early 1970s: The M60A2 and MBT-70 have been costly failures, the M60A3 was not yet ready, and hundreds of M60s and M60A1s had been rushed to Israel to replace their tank losses in the 1973 war.  Therefore, the US military found itself short on tanks.  This led to the M48A5, which was essentially an M48 with a lot of the components of the M60A1 and some from the upcoming M60A3.  Though the M48A5 was originally to be an interim design, Chrysler found there was a ready market overseas for the M48A5, and production of upgrade kits and new production M48A5 exceeded expectations. The M48A5 was not ready, however, until 1976; by then, the only US units to receive the M48A5 were National Guard, Reserve, and tank battalions of the 2^nd Infantry Division in Korea.

     The engine of the M48A5 was a variant of the M48A3’s engine, the AVDS-1790-2D, along with an improved transmission.  In addition, the engine compartment was rearranged, as was the rear deck itself.  Using experience from the Israelis, the M48A5 incorporated a new commander’s cupola, called the Urdan cupola (though early-production M48A5s still used the M1 cupola with a riser).  The Urdan cupola was not equipped with a machinegun; instead, M60D machineguns were mounted on pintles in front of the commander’s cupola and the loader’s hatch.  (The commander’s pintle could also accommodate an M2HB, something done by many foreign armies, but not standard in the US military.)  The Urdan cupola had a pop-up hatch that allowed the commander 360-degree vision with little exposure, as well as all-around vision blocks.  The Urdan cupola also had a much lower profile, yet was much less cramped than even the M1 cupola on a riser.

     Perhaps the most dramatic modification to the M48A5, however, was the replacement of the 90mm gun with the M68 105mm rifled gun fitted to the M60 series.  First done on M48A3s, and then done almost en masse by the Israelis on their M48A3s, this proved to be a relatively easy upgrade for the M48A5; the M48A3 was actually designed for the retrofitting of a 105mm gun, and the other primary modifications was replacement and rearrangement of the ammunition racks.

*If the TF or TR of the M48A4’s turret is hit, roll an additional 1D10.  If a 1-3 is rolled, the “hit” is actually a miss.

**The M48A4 cannot move when firing a Shillelagh missile, and must remain stationary until the missile hits (or misses) it’s target.  If the M48A4 is forced to move, the Shillelagh automatically misses.

***Any of the Shillelagh missiles may be replaced with a conventional 152mm round, up to all 12.  They will fit into the same storage racks as the Shillelagh missiles.

Chrysler/GDLS M60

     Notes:  Originally a meant to be a simple improvement of the M48 series (the test vehicles for the M60 were in fact designated the M48A2E1 at first), the M60 grew into a much more complicated and sophisticated tank than its predecessor and took on a life of its own.  Though no longer in active, reserve, or National Guard service as a main battle tank, variants of the M60 continue to serve in the US military, and since they have been widely exported, serve in the armies of at least 20 foreign militaries, with several others having scrapped them or sold them off in favor of newer tanks.  In addition, the M60 is a common testbed for new ideas, and several variants, both domestic and foreign, are still in service or are offered for export sales.  Though sometimes called the “Patton” since its processors used the same name, this is not an official M60 appellation.

The M60

     Development of the M60 began in early 1954.  From the beginning, a diesel engine was decided upon to power the M60, as the M48A2 that the M60 was designed to replace still used a fuel-hungry and fire-prone gasoline engine. Eventually, Chrysler settled upon the Continental AVDS 1790-2 diesel engine.  (Originally, the M60 was to have an APU, but this idea was dropped as unnecessary due to the lower fuel consumption of the diesel engine.) This engine was much smaller than the previous gasoline engines and also retained most of its effectiveness in very cold as well as hot climates.  The main armament chosen was the British L-7 105mm rifled gun; modified for use on American tanks, it was designated the M68 (the M68 has a few less parts and is designed to fit US gun mantlets).  This was after a months-long wrangling session, trying to decide whether to take a chance on British and German 120mm guns in development.  Essentially, the Department of Defense decided they needed a new tank now, not later.  The gun was fitted with something that was a relative rarity at the time, a bore fume evacuator, but the original M60s used the same fire-control suite as the M48A2.

     Originally, the M60 was to have siliceous cored armor on the turret front and glacis.  Siliceous cored armor was essentially a very primitive form of the Chobham that would appear much later.  However, to simplify production and reduce costs, this type of armor was deleted, and all armor on the M60 was RHA instead.  The original turret was essentially identical to that of the M48A2, with some internal differences, allowanced for the larger gun, and an increase in armor protection.  The commander’s station used a new type of cupola, however, somewhat larger than the cupola of the M48A2.  This turret was equipped with the then-new M48 .50-caliber machinegun to same space (original plans were for the use of the M2HB).  The floor of the turret had an armored escape hatch for when the vehicle was on fire and exit through the crew hatches was impossible due to the tactical situation.  The hull used a wedge-shaped nose instead of the elliptical nose of the M48 series, as this would have facilitated the original idea of using siliceous cored armor.  The new hull design also allowed the entire hull to be made from a single casting or by building it from several smaller castings. Suspension was a modified form of that of the M48A2C, but the roadwheels were of aluminum alloy, and the suspension had no hydraulic shock absorbers or friction reduction mechanisms.  The front and rear roadwheels did have bumper springs to limit their travel.  Early tests led to shock absorbers to being retrofitted, as the former stiff suspension led to firing stability problems and rapid crew exhaustion.

     As stated above, the cupola of the M60 was armed with the M85 heavy machinegun, fed by a 180-round ammunition box inside the left rear wall of the cupola, and ejecting spent shells through a chute on the right side of the cupola. (Early M60s were sent from the factory with M2HBs on a pedestal mount atop the cupola, as the M85 was undergoing developmental problems; the M85s were retrofitted a few months later.)  The commander had eight vision blocks in his cupola, one of which could be replaced by a night vision periscope, but the vision blocks gave him only a 180-degree field of vision.  The cupola could be rotated independently of the turret, but rotation of the cupola was by a manual crank. The commander had override controls for the 105mm gun, but aiming was a rough estimate for the commander, as he had nothing more than a crude sight for the main gun.

     The gunner had a simple gunsight, little more than a coincidence rangefinder aided by a primitive computer.  Controls were electric, and the coaxial armament was an M73 electrically-fired 7.62mm machinegun.  Most ammunition was carried in the hull – only six rounds were carried in the turret bustle (increased to eight rounds a few years later when more compact radios were retrofitted).  The loader had a hatch on the turret deck; it moved up and slid out of the way instead of being a normal hatch.  The driver had a hatch on the front deck, but his controls were otherwise basic, with a wheel-type steering yoke.  Vision blocks extended to the front and left side of the hatch.  The crew had a heater; the exhaust pipe tended to get clogged by flying mud during normal operation, so to prevent crew asphyxiation, the driver’s hatch was normally left cracked open slightly when the heater was being used.  Some 2205 “plain vanilla” M60s were built before being replaced in production by the M60A1 in 1962.

The M60A1

     The M60 was a decent tank for the time, but it could have been better.  Development of the M60A1 began in early 1960, when Chrysler tried three new turrets on some of its pilot vehicles.  The turret eventually chosen was an elongated turret based on that of an older tank program, the T-95E7, allowing for a larger turret bustle.  The suspension gained another pair of hydraulic shock absorbers.  The engine was replaced with an upgraded version of the original engine – the AVDS-1790-2A, with a reduced exhaust signature and somewhat reduced fuel consumption.

     The replacement of the original mechanical linkages with hydraulic linkages allowed the substitution of a T-bar-type steering yoke and rearranged accelerator and brake pedals.  This gave the driver’s compartment some much needed room, a bit more power steering, and in general increased the driver’s comfort level.  The seats of the M60, which were bare wire mesh, were replaced with metal and plastic seats with padding, and the driver’s seat was replaced with a contoured bucket seat.  The commander now had a choice to two seats – when riding in the cupola with the hatch open, he used an upper swivel seat on a spindle at the rear of the turret roof.  When buttoned up, the commander shifted to a folding seat that could slide up and down on a post, which allowed him to ride at any height between the turret floor and just high enough to see out of the vision blocks in the cupola and operate the M85 machinegun.  (He could also stand on the seat and use it as a platform when the cupola hatch was open.)  The gunner’s seat had a removable backrest, and the loader’s seat was removable and could be stowed away.  When in use, the loader’s seat could be attached at the left of the gun or higher so that he could sit and see out of his open hatch. Armor protection was increased in most areas, and the sides of the hull of the M60A1 were given a very slight sloping to increase effectiveness of the armor. 

     The ballistic computer was replaced with a more compact model (though today, a pocket calculator could provide the same computing power).  The gunner was given a better coincidence rangefinder with 10x magnification, as well as another periscope for use as a backup sight.  The gunner also had M35 periscope head vision block, which gave him both daylight vision and night vision.  The commander had a similar vision block in his cupola, and a second periscope was a binocular-type periscope.  The coaxial machinegun was replaced with the M219 machinegun, which was unfortunately about as prone to failure as the M73.  Though at first not included, virtually all M60A1’s were later fitted with a huge Xenon white-light searchlight above the main gun mantlet.

     It should be noted that at the time of its adoption, the M60A1 was meant to be only an interim vehicle.  Early design work had already begun on the tank that would become the MBT-70, and ultimately the MBT-70 program went down in flames.  This meant that M60A1 production would continue for over 20 years, with many modifications here and there.  The US Marines were using M60A1s equipped with ERA as late as Desert Storm.

The M60A2

     And now for something completely different…

     The M60A2 was an attempt to dramatically increase the firepower and long-range gunnery of the M60 series.  The genesis of the M60A2 goes back as far as the ARCOVE report of 1958, which had as one of its recommendations the development of a gun/missile launcher for tanks and support vehicles (and eventually gave us the Shillelagh ATGM).  The Shillelagh ATGM and its gun began development first, then a turret for what became the M60A2 and the vehicle that became the M551 Sheridan were developed in tandem.  Turret candidates for the M60A2 were not available until early 1964.  Problems with the new turret, gun, ammunition, fire control, and layout led to almost continual changes in the design, and the first operational test vehicles were not ready until 1968.  The M60A2 did not reach full operational status until 1973, and only 540 were built (mostly modified from M60A1s).

     The resulting M60A2 – well, you can tell that the hull is an M60A1s, but the turret looks like nothing seen on any other tank, ever.  On either side of the turret, there is merely a low-stepped turret ring; in the center, there is a large, blocky middle section containing the gun and the commander’s station behind the gun.  This arrangement reduced the frontal cross-section of the M60A2’s turret as well as decreasing weight.  The loader and gunner had small hatches on either side of the turret, barely above the turret ring.

     The M60A2 was armed with the M162 152mm gun-missile launcher.  As the primary accent of the M60A2 was to fight at long range with the Shillelagh, and a long 152mm gun tube would have been quite heavy, the length of the M60A2’s gun tube was a mere 2.67 meters – only an L/17.52 gun.  The M162 gun was designed to fire only the MGM51C version of the Shillelagh – earlier versions of the missile could not be used.  Conventional rounds were also devised, but early problems with the new combustible case rounds, specifically flash-back upon opening the breech, led the original bore evacuator to be replaced by a closed-breech scavenging system (CBSS) to be devised – the gun tube was literally blown clean by three blasts of compressed air given by a pair of air compressors that led to a pair of compressed air storage bottles, and these gave blasts of 1000 psi compressed air.  If the system worked right, it only slightly slowed the reloading rate, and it was not necessary when using the Shillelagh.

     Initially, one of the biggest deficiencies with the M162 gun-missile launcher was the fire control suite.  Due to the shape of the turret, most US military fire control components and night vision equipment would not fit.  This left a tank with no rangefinder and no night vision equipment for the gunner.  A white-light Xenon searchlight was mounted on the left side of the turret, but long-range shots at night (especially with the Shillelagh) were basically impossible, unless the crew could get their searchlight on the target.  (You don’t want to be the crew of a tank shining a giant searchlight on a battlefield at night!)  Eventually, this problem was solved by a new generation of night vision equipment, a new ballistic computer, and one of the first laser rangefinders employed by the US Army, but for a while, those poor M60A2 tankers had serious problems.

     The commander’s station was atop the turret at the rear.  The commander had 11 vision blocks with overlapping vision arcs giving 270-degree vision (all except to the left), and the top of the cupola had an M51 day/night periscope, with a day magnification of 10x and a night magnification of 8x with IR vision.  The commander also had the ability to take control of main gun and fire when the gun was loaded with conventional rounds, and he could also remotely fire the coaxial machinegun.  The commander’s machinegun was on a semi-external mount (it looks similar to the 20mm autocannon mount on the Marder) to the left of the commander and used an M48 machinegun.  Cupola traverse was electric. 

     The gunner, on the right side of the gun, had at first very little in the way of fire control equipment – little more than an articulated telescope that was meant primarily to track Shillelagh missiles in flight.  Eventually, the gunner got a modified form of the day/night periscope used on the commander’s cupola, and the AN/VVS-1 laser rangefinder that was slaved to a new ballistic computer.  The system was quite accurate – and also very buggy, and crew complaints were common.  The coaxial machinegun was at first the M73, but was soon replaced by the M219. The loader had an M37 periscope in his hatch.  The driver’s position in the M60A2 was essentially the same as in the M60A1.  The turret of the M60A2 also had eight smoke grenade launchers, with the grenades launched electrically from the commander’s cupola.

      The M60A2 ultimately had a very short service life – about five years.  The complex system was nightmarish from a maintenance standpoint, the turret cramped, the CBSS tended not to properly evacuate fumes, and vision for the gunner and loader could be a problem.  The M60A2 got sort of a mocking nickname – the “Starship.” The Shillelagh missile had a long minimum range and a relatively short maximum range, and was found wanting in the accuracy department.  Even given the weight of the M60A2, the recoil of the 152mm gun could still be pretty heavy.  I can still remember, from my first duty station in the Army at Ft. Stewart, hearing some of the older mechanics bitching about servicing the turret, especially the turret ring.  The development of more advanced cannon armament, especially long-range kinetic energy rounds like APFSDS, meant that the gun-missile system wasn’t necessary for long-range shots; therefore, the M60A2 was no longer necessary.  Though a majority of M60A2s were converted back into M60A1s or into M60A3s, some were made-over into AVLBs or mine-roller vehicles. 

The M60A3

     By the late 1960s, there had been many technological and automotive advances in tank design.  The M60A1 was becoming an outdated design compared to the tanks of the US’s NATO allies, particularly the German’s Leopard 1.  The M60A1 was the recipient of several incremental upgrade programs, culminating in the M60A3, which entered service in 1979.  

     One of the first improvements was the commander’s cupola.  The vision blocks were replaced by a ring of 11 larger vision blocks, one of which could be replaced by a day/night periscope.  The new cupola had a better shape from a ballistic standpoint, and also had improved armor protection.  It also included a hydraulic/electrical traverse, eliminating the hand cranking.  The M85 machinegun was slightly offset to the left, making it easier to service the weapon and allowing an increase of ready ammunition from 180 to 270 rounds.

     Automotive improvements included a top-loading air cleaner that reduced the dust and dirt ingestion that was a problem on the M60A1, and made the air cleaner easier to service.  The housing for this air cleaner was later given an armored steel box to protect it. The tracks were replaced by T-142 steel tracks with a new rubber track pad arrangement that had longer life and made replacements of the pads much easier.  These tracks were also somewhat wider, granting an increase in off-road performance.  The component of the M60A1 with the highest rate of failure was the power pack, and several possible replacements were considered, including two with much higher horsepower outputs.  However, due to concerns about fuel consumption, the power pack was replaced with a RISE (Reliability Improved Selected Equipment) version of the M60A1’s engine, the AVDS 1790-2C, which had the same horsepower rating but was more reliable and made better use of the available horsepower.  The electrical system was almost completely replaced with more reliable components that were also simplified and easier to service.  The mobility of the vehicle was further enhanced by replacing the standard torsion bar suspension with a tube-over-bar (TOB) suspension, which essentially increased the up-and-down movement capability of the roadwheels by effectively doubling the length of the torsion bar springs.  The shock absorbers were also replaced by rotary shock absorbers, which improved dissipation of heat that built up in the shock absorbers.  The aluminum alloy roadwheels were replaced with steel roadwheels due to cracking problems.  The M60A3 also had the capacity to lay a smoke screen by injecting diesel fuel into its exhaust.

     Large improvements to the fire control suite and the main gun were made.  The optical rangefinder was removed; in its place was installed the AN/VVG-2 laser rangefinder.  The older ballistic computer was replaced by a more compact and capable M21 ballistic computer.  The commander received a day/night 6x-12x range-finding telescope in his cupola; fire solutions from this rangefinder and the gunner’s laser rangefinder could be integrated by the M21 ballistic computer to provide a more precise fire solution (though the commander’s rangefinder had a minimum range of 200 meters).  The gunner’s image intensifier was replaced with a thermal imager (the TTS, or Tank Thermal Sight) starting three months after first fielding, with the resulting tanks being designated the M60A3(TTS).  The M60A3 had an array of other sensors that allowed the ballistic computer to compensate for drift, crosswinds, target motion, altitude, the wear of the gun tube, cant, sight parallax, recoil, and gun tube droop as the barrel heated up. 

     On each side of the turret, British-designed 6-barrel M239 smoke grenade launchers were mounted.  (The US Marines later replaced these with 8-barrel smoke grenade launchers.)  The coaxial machinegun was replaced with a version of the FN MAG machinegun, the M240C.  This machinegun could be electrically or manually fired, as well as dismounted from the vehicle and put on a tripod by using a spade grip kit or stock kit.  The gun barrel received a thermal sleeve to combat barrel droop as the barrel heated up in sustained fire.  Another addition was a radiac meter for the crew to test the radiation levels outside of the tank.

GDLS M60 Modernization Package

     In the late 1980s, GDLS developed an upgrade package for the M60, both for export and for existing US M60A1 and A3 tanks (at the time, whether or not the Army National Guard and US Marines would receive their M1 Abrams tanks in a timely fashion was in doubt).  This upgrade package included improvements to the armor, power pack, fire control system, and ammunition storage.  Though as of yet this upgrade package has not been picked up by any M60 users (most of which are buying newer-design tanks), GDLS is still offering the upgrade.

     Fire control upgrades include a modified version of the M1 Abrams’ gun stabilization system, ballistic computer upgrades, and upgrades to existing systems controlled by the ballistic computer.  The engine is replaced by one of two versions of the AVDS-1790, developing 908, 1050, or 1200 horsepower; the transmission is also upgraded to match the new engine.  The suspension is also upgraded, giving a smoother ride and better fire-on-the-move.  New tracks are fitted.  Armor protection is greatly improved using appliqué armor, and ERA lugs are standard.  The turret has an enlarged bustle with blow-out panels similar to those on the M1 Abrams, and offering the same protection in the case of a turret ammo explosion.  Improved and rearranged ammunition storage allows for more ammunition to be carried.  The cupola is replaced with a conventional commander’s station, with vision blocks and an M2HB heavy machinegun that can be aimed and fired remotely.

     Israel devised an ERA kit for the M60A3, and this was quickly picked up on for US Marine M60A3s and some US Army M60A3s that were still on active duty (as late as 1989, I still saw some in Korea belonging to 2ID).  Often, these vehicles also have track skirts added.  Many other countries operating the M60A3 and M60A1 also applied ERA to their M60s.  (The M60A3 with ERA is the tank that the US Army Vehicle Guide and American Combat Vehicle Handbook refer to as the “M60A4.”)  The faces covered by a full kit include the HF, HS, TF, TS, and the forward part of the turret deck.  There is a kit to extend the mount for the smoke grenade launchers that may be fitted when the TS ERA is applied.  (In of itself, a full ERA kit for the M60A1 or A3 weighs 450 kg and costs $150,000, plus 500 kg and $4000 for the side skirts.)

M120S

     At first referred to by as the M60-2000, GDLS now refers to this Abrams/M60 hybrid as the M120S, with the “120” referring to the gun caliber and “S” referring to Survivability.  The M120S is an attempt by GDLS to quickly and less expensively produce a dramatic upgrade for the M60 series.  The M120S (an unofficial, company designation), is still being marketed heavily by GDLS, and came within a hair’s-breadth of being adopted by Turkey (already the user of a large fleet of M60A3’s), but as yet no sales have been made. Egypt has also shown some interest in the M120S, as they too have a fleet of former-US M60s.

     Though the M60 chassis is obvious with a close look, the M120S does have a great resemblance to an actual M1A1 Abrams.  The turret is essentially the same as that of the M1A1, but with no DU armor inserts.  The turret is mounted on the M60 chassis with an adapter ring.  As the M1A1 turret is much heavier and extra armor is added to the M120S, the suspension has been beefed up considerably to take the extra weight, and the tracks have been replaced with lighter, yet stronger ones.  The standard torsion bars have been replaced with hydropneunmatic units to smooth the ride, as well as saving space within the hull.  The sponsons have been enlarged to hold batteries and extra fuel.  The powerpack has been replaced with an AVDS-1790-9 1200 hp diesel and a matching automatic transmission.  The M120S uses M1A1-type final drives and M1A1-type driver’s controls.  Armor enhancements include side skirts and Chobham glacis armor, as well as general hull armor augmentation and lugs for ERA on the HS and TS.  The M120S has an external APU similar to that used on some versions of the Abrams, a digital command-and-control computer, thermal vision for the driver, a CITS (Commander’s Independent Thermal Sight), general improvements to the electrical system, and monitors for the vehicle equipment condition.

     A number of odd variants of the M60 were devised, designed, or tested.  Eventually, these will be found in the Best Vehicles That Never Were Section.

     Twilight 2000 Notes: A good number of US tank strength in the Twilight 2000 timeline, especially in US Army reserves and the National Guard, were actually M60A3s; at the beginning of the war, most of them sported ERA.  The US Marines also had a good number of M60A3s and a few M60A1s on hand, also normally equipped with ERA.  In other places in the world, M60A1s and A3s are also quite common.  The GDLS Modernization Package (designated M60A4E1 as used by the National Guard and M60A4E2 as used by the Marines) was used extensively by the Army National Guard and the US Marines; the Army National Guard typically used the 1050 hp engine, while the Marines used the 1200 hp engine.  Several other countries took advantage of the GDLS Modernization Package.  Starting in 1997, some 250 M60s were modified to the M120S standard, and type-standardized as the M60A5; however, they were more commonly known to their crews as the “Abrams Junior.”  Some 75-90 were sent to the European and Middle Eastern Theatres, but most did not make it out of the continental US, and most were sent to Alaska and the Pacific Northwest to fight the Russian invasion, with about 40 sent to the American Southwest.  Most used reactive armor in an attempt to match the superb armor protection of their turrets.

*If the TF or TR of the M60A2’s turret is hit, roll an additional 1D10.  If a 1-3 is rolled, the “hit” is actually a miss.

**The M60A2 cannot move when firing a Shillelagh missile, and must remain stationary until the missile hits (or misses) it’s target.  If the M60A2 is forced to move, the Shillelagh automatically misses.

***Any of the Shillelagh missiles may be replaced with a conventional 152mm round, up to all 13.  They will fit into the same storage racks as the Shillelagh missiles.

****These AV figures are when equipped with ERA.  If the tank is not hit with an HE-type warhead, subtract 80 AV from the TF, TS, HF, and HS (depending upon where the incoming round hit).  When equipped with ERA, the forward half of the turret deck has an AV of 84 when struck by an HE-type round.

*****These AV values are when equipped with ERA.  If the M120S is not hit with an HE-type warhead, subtract 80 AV from the HS or TS (depending upon where the incoming round hit).

GDLS M1 Abrams

     Notes:  Rising from the ashes of the German-US MBT-70 program, the M1 Abrams was designed to cure a major problem in the US arsenal – US (and most NATO) main battle tanks of the 1950s, 1960s, and 1970s were simply not able to match their Soviet counterparts, even with the many faults of Soviet armor at the time.  Israeli experiences in the 1956, 1967, and 1973 wars simply confirmed those conclusions, as the Israelis were using many of the same tanks in those wars which would have to fight in Europe if World War 3 broke out.  There was a growing realization that NATO had been very lucky that the Soviets had been too worried about Mutual Assured Destruction and what the Soviet leaders believed that NATO was capable of to actually start World War 3.

     After the MBT-70 program (and a less-expensive and complicated alternative, the XM803) went down in flames, US designers started from scratch. The Pentagon first appointed a special task force, comprised to a large extent of senior NCOs and officers with primary backgrounds as tankers; this task force, the MBTTF (Main Battle Tank Task Force) began their work in early 1972, and reported directly to General Creighton Abrams (then the Army Chief of Staff; as General Abrams died before the M1 was fielded, it was given the name Abrams in his honor).  It was quickly decided to use the new British armor known as Chobham (actually known by the code designation of “Burlington” in Britain – Chobham is a village near the labs where the armor was developed) for critical areas – but to the dismay of the British designers, the US Army’s Ballistic Research Laboratories actually improved upon Chobham.  (The American version was unofficially called BRL 1, but it and later versions are simply referred to as “special armor” by the US military.)  Several contractors submitted designs for the XM1, but only the designs submitted GM and Chrysler survived to the prototype phase; in the end, Chrysler’s design became the M1 Abrams.  (Due to financial problems, Chrysler sold its Defense Division to General Dynamics in mid-1982; virtually the entire M1 series has actually been built by General Dynamics Land Systems.)  LRIP (Low-Rate Initial Production) began in early 1980, and full production in late 1981.  First issue to Army units began in 1982, with the M1 Abrams I.

     Interesting Note: The first XM1 was rolled-out on 28 Feb 80, with General Abrams’s wife and his 3 sons in attendance.  It was not revealed until this ceremony that the name of the M1 would be the Abrams.  Up until just before the rollout of the XM1, the tank was going to be called the Marshall (after the father of the post-World War 2 reconstruction plan, General George C Marshall). However, it was felt that it was better to name the M1 after Creighton Abrams, an armor hero that had fought since the end of World War 2 for the kind of tank that became the M1, and rode herd over the initial M1 design program; he had died of cancer in 1974, while still on active duty.  When that first XM1 was rolled out, the name Thunderbolt had been stenciled on the turret – this was the nickname Creighton Abrams usually gave to whatever tank had been assigned to him, throughout his career.

The M1 Abrams I

     The M1 Abrams I was the first version of the M1 Abrams series, produced from 1980 to 1985.  The M1 was a quantum leap forward in tank design at the time of its introduction, with a comprehensive fire control suite, gun stabilization mechanism, and night vision devices.  The use of the powerful AGT-1500 gas turbine engine was perhaps the first use of a gas turbine in an armored vehicle in a large scale – the gas turbine, being essentially a type of jet engine, offers incredible power, torque, and acceleration while remaining a relatively small (if fuel-hungry) unit.  The AGT-1500 is also a multi-fuel engine, capable of burning gasoline, diesel, an ethanol/gasoline or diesel mix of up to 20%, JP-4 or JP-8 jet fuel, or kerosene; in extremis, the AGT-1500 can also burn pure ethanol or methanol with some modification.  The M1 also uses a special type of ammunition storage that was also rare up to that point: it incorporates blowout panels that use covers on top of the bustle which offer a “route of least resistance” in the case of an ammunition hit that causes the ammunition to detonate inside the vehicle.  If the main gun ammunition supply in the turret (but not the hull) is detonated by a weapon hit, the M1 is not automatically destroyed.  Instead (in game terms), the main gun ammunition in the turret is destroyed, the armament, sensors, and electronics each take minor damage, and each member of the crew except the driver takes 50 points of concussion damage.  80% of the main gun ammunition carried on board the M1 is carried in the turret.  2,374 M1s were built before production shifted to the IPM1.  Most were later upgraded to the IPM1 standard or to the standard of later models, but some were converted into M104 Wolverine bridgelayers or mine-clearing vehicles.  Those that do remain in service are found only in National Guard and Reserve units, and they are by 2008 found in very small numbers.

     The primary armament of the base M1 series is a modified version of the Royal Ordnance L-7 105mm rifled gun, designated the M68 (the M68 is slightly modified to allow the L-7 to use standard US gun mantlets).  During the design process, the main armament was a bone of contention, primarily between the bean counters that wanted to save money and the military, who knew that the 105mm gun was rapidly becoming less and less capable of handling the newer Soviet tanks being fielded at the time.  A compromise was eventually worked out – the M1 would be armed with the L-7, but the turret was designed to that a variant of the Rheinmetall 120mm gun could be later retrofitted.

     Like many armored vehicles designed to use diesel fuel, the entire M1 series (except for some of the M1A2 SEP tanks) had the ability to quickly lay a thick, oily smoke screen by spraying diesel fuel directly into the tank’s exhaust.  The VEESS (Vehicle Engine Exhaust Smoke System) was no longer usable by the end of the 1990s, when most of the US ground vehicle fleet had been switched over to JP-8 as a motor fuel (it could still be sprayed into the exhaust, but as JP-8 doesn’t generate smoke in that manner, it was pointless).  The VEESS was therefore removed.  The M1 series is also equipped with smoke grenade launchers (also common on modern armored vehicles).  The original launcher was the M250 system, which used twin banks of six smoke grenade launchers on both sides of the turret (using non-explosive 66mm grenades with red phosphorus filler and a launching charge to generate the smoke).  The grenades are fired from inside the turret in groups of three; if necessary, up to the entire complement of 24 grenades can be fired at once. In 2004, replacement of the M250 system by the new M6 system began, though as of the time of this writing (May 08), not all Abrams tanks have had their M250s replaced.  The M6 system is similar in appearance to the M250, but more flexible; it is able to colored smoke, IR-defeating smoke, and flares (normally used to decoy the heat-seeking guidance systems that most fire-and-forget ATGMs use).  (It should be noted that USMC M1A1s use similar smoke grenade launchers [and later decoy/grenade launchers], but their launchers use twin banks of eight launchers on either side of the turret instead of six.) The M1 has full NBC protection, including overpressure.

     Production of the IPM1 (Improved Product M1, though sometimes, incorrectly, called the Improved Protection M1) began in 1984, and by February 1985, it had replaced the base M1 in production. The IPM1 Abrams I’s primary improvement is the addition of a layer of depleted uranium mesh to the frontal arc of the turret and glacis (though initially viewed with suspicion by its crews, the greater protection was very much appreciated by those crews that went to combat with it).  The IPM1 also added a feature that had been requested by M1 crews from the beginning – a bustle rack to carry most of their personal gear; on the M1, the crew has to strap their rucksacks, duffel bags, sleeping bags, water cans, etc., to the outside of the vehicle, or fabricate ad hoc stowage racks of their own – or worse yet, try to put it in the already-cramped interior of the vehicle.  The IPM1 is unfortunately a little heavier, but for the most part performs the same as the M1 above for game purposes.  894 of these vehicles were produced between 1984 and 1986; as with the base M1, most have been upgraded to the standards of later models or converted into other M1-based vehicles.  Those IPM1s that remain are found only in National Guard and Reserve units, in very small numbers.

The M1A1 Abrams II

     In 1985, Abrams production switched to the M1A1 Abrams II.  The M1A1 has further upgraded armor, and the main gun is replaced with an M256 120mm gun; the M256 is based on the German-designed Rheinmetall 120mm gun, but has fewer operating parts.  The simplified gun weighs less than the Rheinmetall design and is less prone to mechanical failure, but has few parts in common with the German-designed gun.  The M1A1 has an integrated NBC overpressure system; in a chemical or radiological environment, the crew is not required to wear protective masks or clothing, as the air is filtered and cleaned before being pumped in from outside.  The M1A1 has air conditioning and heating.  The US Army and Marines, as well as the Egyptian Army (which has production facilities in Egypt) use the M1A1.  In 2007, deliveries of 59 M1A1 tanks began to Australia.  The export versions are detailed below.

     In 1988, M1A1 production was further modified to a standard first called the M1A1E1 during testing, and now referred to as the M1A1HA (Heavy Armor).  The M1A1HA has a layer of depleted uranium mesh incorporated into the frontal armor of the turret.  In 1991, new M1A1s coming off the production line were built to the M1A1HA+ standard, with a layer of depleted uranium mesh added to the glacis as well as the turret front. Most of them were originally deployed to Europe, and due to this, the M1A1HA and HA+ modifications were often referred to as the “European Package.”  In addition, M1A1HA+ tanks were equipped with an improvement to the fire control system.

     In 1990, some 80 design and engineering changes were also added to the M1A1.  Many of these changes consisted of items like modified wiring, improvements for maintenance, and suchlike, but most were originally a result of requests for modifications from the US Marines.  Rather than make a special version of the M1A1 for the US Marines, the Pentagon directed that the modifications be made to all M1A1s in production from that point forward, and the resulting package of modifications are often referred to as the Common Tank Changes, and the resulting tanks are sometimes called M1A1 Common Tanks.  Some more easily-noticed modifications include several more tie-down points, provisions for mounting a Deep-Water Fording Kit, and a mounting point for a position reference system.  Though this modification of the M1A1 still uses a common sight for the commander and gunner, space was made in the turret for possible future mounting of a CITV.  (In 1994 and 1995, 134 additional M1A1s were also transferred in ownership from the Army to the Marines, but it is notable that 84 of these did not have the Common Tank Changes, and as of 2005 still did not have them.  I am unsure of their status today.) 

     After receiving their M1A1s, the Marines further modified them by adding a Driver’s Vision Enhancement (DVE) system.  This replaces the driver’s passive IR night vision system with a thermal imager, and (again, as of 2005), the DVE had still not been added to Army M1A1s.  In 2003, the Marines also began a further upgrade program.  These modifications are primarily concerned with battlefield survivability, adding a newer version of the HA+ armor improvements, exhaust modifications to reduce the tank’s IR signature, and as-yet-undisclosed modifications that reduce the radar signature of the M1A1 a bit.  In addition, the thermal imaging systems for the commander and gunner were upgraded to 2^nd generation standards, improvements to target acquisition systems were made, and an eye-safe laser rangefinder with greater range and precision replaced the older laser rangefinder.

     In 1999, the US Army began another M1A1 upgrade program.  This upgrade never had any official designation, but was unofficially called the M1A1 Digitized, or simply the M1A1(D).  Though the US Army originally wanted this upgrade to be applied to all its M1A1s, (bringing them partially up to M1A2 standards) budget concerns prevented this, and only about 200 of these modifications were carried out (mostly to M1A1HA and M1A1HA+ tanks).  The M1A1(D) upgrade showed almost no external differences, but internally, several important features were added, providing a digital command-and-control system to the commander.  The M1A1(D) was given a compact computer, a keyboard and a small monitor at the commander’s station in the turret, an integral GPS system, radios upgraded to improve digital transmission bandwidth, and a wireless internet system.  The computer’s software ties all these added elements together, and allows an M1A1 with these modifications to communicate with other M1A1s so equipped (or, for that matter, other vehicles or sites so equipped; essentially a pre-Blue Force Tracker BMS).  Continuous battle updates are therefore possible, along with the transmission or receipt of updated tactical plans, maps and map overlays, operations orders, and other vital information.  Though it is unconfirmed, it is rumored that computers in an M1A1(D) and later such computer-equipped Abrams tanks also have USB and Firewire ports as well as slots for flash memory and SD memory cards.

     A note on the mounting of the external machineguns of the M1 and M1A1 series is in order here.  On Abrams tanks, the version of the M2HB used as a commander’s machinegun is technically designated the M48.  There are a few differences in the actual machinegun between the M2HB and the M48; the M48’s charging handle is on the left side of the weapon, and consists of a stirrup-like handle connected by a chain to a rod that looks like a longer version of a standard M2HB charging handle.  Feed is from the right side of the receiver and case/link ejection is to the left; a bag or box can be attached to the left side of the M48 to keep the spent brass and links from rolling and bouncing around on the turret or into the commander’s hatch.  On the M1 and M1A1 series tanks, the commander’s machinegun is mounted on a CWS (Commander’s Weapon Station, or “Chrysler Mount,”), which is a low cupola with power controls for rotating the turret and vision blocks.  The M48 is attached to a mount that allows the machinegun to be trained, aimed, and fired while the commander’s hatch is closed, and includes a 3x periscope to assist in aiming.  The M48 can also be unlocked and used in the same manner as a pintle-mounted machinegun.  (It should be noted that when the commander uses the M48 while buttoned up, the loader’s machinegun and the antennas at the rear of the turret can get in the way of the traverse of the CWS; if the loader’s hatch is open, that gets in the way of the CWS’s traverse as well.)  Notably absent is a way to reload the M48 while buttoned up.  The other external machinegun, an M240 GPMG (usually a standard infantry model, but an M240 modified with spade-grips can also be mounted), is mounted at the loader’s hatch on a simple skate-type pintle mount that runs from the left side of the loaders hatch to the right front of the hatch.  The loader’s machinegun tends to obscure the commander’s vision through his vision blocks when the tank is buttoned up, and many M1 and M1A1 crews in Iraq have found that in urban combat, it is often better to remove the loader’s machinegun before entering such an area.

     In 1994, the US Army suspended the refurbishment of their M1A1s going through depot-level maintenance, opting instead for a rebuild program called AIM XXI (Abrams Integrated Management for the 21^st Century).  This has now become the standard for M1A1 tanks still in US Army and Marine service, as well the base standard level for M1A1s that are exported to other countries.  (A few of these iterations of the M1A1 are still in US service at the time of this writing in May 2008, primarily with the US Marines.)  The AIM XXI program essentially rebuilds the M1A1 from the ground up, refurbishing all systems to nearly-new condition, and (if the M1A1 in question does not already have them), upgrading the armor to HA+ standards, adds the Common Tank modifications, adds the eye-protective vision blocks to the commander’s station that the M1A2 uses, and (if export restrictions allow it), adds improvements to the fire control and target acquisition systems, upgrades the thermal imager to 2^nd-generation standards, and includes the M1A1(D) upgrades.

The M1A2 Abrams III

     The M1A2 Abrams III version of the Abrams began production in 1992, with deliveries beginning in November of that year.  The accent on the M1A2 was survivability, but it also tied together many of the disparate upgrades that were done to previous models.  The M1A2 was originally to have a greater level of armor protection than even the M1A1HA+, but the GDLS designers quickly discovered that this would have increased the weight of the already-heavy M1A2 design by another 4 tons, and protection remained at M1A1HA+ levels.  Nonetheless, a redesign of the armor allowed GDLS to keep the same level of protection as the M1A1HA+, yet lighten the armor package.  The redesign also made armor damage easier to repair.

     The ammunition racks in the turret bustle were also redesigned and rearranged, allowing them to hold an additional two rounds of main gun ammunition.  Perhaps the most noticeable external difference from the M1A1 series is large, drum-like periscope ahead of the loader’s hatch; this is the CITV (Commander’s Independent Thermal Viewer).  Though there had been space in the M1A1’s turret for a CITV since the M1A1 Common Tank modifications, the CITV was not installed until the advent of the M1A2.  The CITV was an important addition, and one that Abrams crews had been clamoring for from almost the beginning.  Until the M1A2, the sighting and thermal imaging system on an Abrams was shared by the gunner and commander; since the gunner had priority on the sights when engaging targets, the commander had to look for new targets by standing up in his hatch and viewing the battlefield through binoculars or a hand-held image intensifier or night-vision device of some sort.  The CITV allows the commander to look for new targets as the gunner is engaging other targets – making the M1A2 crew into “hunter-killers” and increasing by as much as 50% the rate at which the M1A2 crew can find, engage, and destroy targets.  If necessary, the commander can also access the gunner’s sight and viewer, and overrides for the main gun and coaxial (long a part of tanks in the world, including earlier versions of the Abrams) allow the commander to quickly attack close-range targets that the gunner may not have time to notice in the heat of battle.

     Another very noticeable difference between the M1A1 and the M1A2 is found on the left side of the bustle rack – an 8kW APU.  It had long been known that fuel consumption of the turbine engine of the Abrams is almost as high when the tank is idling as it is when moving at full speed; when the Abrams has to idle in place for long periods (such as when conducting overwatch duties, waiting in ambush, defending a fixed position, etc.), an Abrams can burn through entire tanks full of the same fuel it needs to move. (During Desert Storm, a lot of M1s ran their fuel tanks dry just idling, before fuel trucks arrived.)   Makeshift solutions, such as BRAs (Battlefield Refueling Apparatus – 303-liter rubber fuel bladders with portable pumps) strapped to the sides of the hull and/or turret, proved to be ineffective and downright dangerous – most crews would immediately drop them the first time they were fired upon, and during the initial invasion of Iraq in 2003, one Marine M1A1 burned up after one of its BRAs was penetrated by API small arms fire (the crew got out safely).  An add-on APU was available in limited numbers for the M1A1 – but mounted on a semi-makeshift rack that sort of hung off the left rear deck, and having only thin steel plating to protect it, it was vulnerable to enemy fire and everyday damage as well as being just plain clumsy.  The M1A2 adds a diesel-powered 8kW APU of conventional design in order to cut down on this extra fuel use, mounted in an armored box and taking up almost the entire space where the left side of the bustle rack was.

     The M1A2 not only has the same sort of digital command-and-control package as the M1A1(D) – it improves upon it.  The entire system is tied together with a more powerful computer and a set of sub-processors to control various elements of the system.  An IFF (Identification Friend-or-Foe) unit was added, allowing the M1A2 to broadcast a signal to friendly units to help keep it from becoming a victim of “friendly” fire.  Like modern cars, small microprocessors also control aspects of the M1A2’s mechanical operation, as well as providing diagnostic information for the various subsystems of the tank – leading to one of the nicknames for the M1A2, the “Electric Tank.”  The M1A2’s systems also make part of the FBCB2 integrated battlefield system; the crews of vehicles with IVIS (Inter-Vehicular Information System) can keep in secure real-time contact at all times, which gives them an important edge in today’s rapidly-changing battle situations.

     Other external differences in the M1A2 include the vision blocks around the commander’s hatch; they give a wider field of vision, and are designed to protect the commander from laser dazzlers (lasers designed to blind enemy troops) and other types of lasers that may not be eye-safe.  The mounting of the commander’s M48 machinegun is also different – the complex CWS is completely gone, replaced by a simple pintle mount and a ring of vision blocks mounted directly on the turret around the commander’s hatch.  This reflects the prevailing attitude at the time of the M1A2’s inception – the commander’s primary job is issuing orders, receiving instructions, and looking for new targets, and the M48 is only supposed to be a backup “emergency” weapon for close combat.  (This proved to be a bad decision in light of the type of combat occurring in Iraq and Afghanistan, as the crews often find themselves fighting buttoned up.  Modified versions of the Stryker-type RWS’s are belatedly and very slowly being added to M1A2-series tanks.)

The M1A2 SEP Abrams III

     The M1A2 SEP (System Enhancement Package; its crews also refer to this version as the “SEP”) further improves on the command-and-control system of the M1A2, as well as increasing survivability and some improvements in other elements.  The SEP began deployment in 2001, though the improvements that eventually became the SEP began design in 1994.  Unlike most other members of the Abrams series, the M1A2 SEP fleet consists almost completely of upgraded M1, M1A1, and M1A2 tanks, some of which have been almost totally rebuilt.  The SEP is now the standard version of the Abrams in production; most US Army Abrams are built to at least this level.

     The computers of the SEP are enhanced, using faster processors and greater amounts of faster memory; disk storage was also increased.  The interface for the computer OS is also simplified, making data input and general use of the system far easier; in addition, the small computer monitors used in the M1A2 SEP are also color monitors instead of monochrome. The commander’s and gunner’s thermal imagers are replaced with a 2^nd-generation FLIRs – more akin to a FLIR one would find in a helicopter or aircraft than one would normally find in a ground vehicle.  Fire control and target acquisition is also improved, making both faster.  Additional armor, more advanced than used on the base M1A2, was added to the SEP’s frontal arc; though the composition of this improved armor has not yet been revealed, it is widely believed that it is still based on the DU mesh of other Abrams models.

     The APU of the M1A2 was found to have many shortcomings; it had a large thermal signature, it was bulky, and vulnerable to enemy fire due to its comparatively thin armor (capable of stopping little more than heavy-caliber small arms rounds).  In addition, the APU’s mounting resulted in a huge loss of storage space to the crews, meaning that the crews once again found themselves tying large amounts of gear to whatever space they could find on the exterior of the vehicle, which can cause lots of tactical headaches.  The SEP does not have this APU, but in part of that space (less than half of it), the SEP does have small air conditioning unit called a TMS (Thermal Management System; according to the Army, the TMS is there to protect the electronics, not provide crew comfort.).  The TMS does not provide heavy-duty cooling – it merely maintains the interior temperature of the tank at a level between 80-95 degrees Fahrenheit (and the metallic surfaces of the interior of the M1A2 SEP can still rise as high as 120 degrees), even if the external temperature rises as high as 140 degrees Fahrenheit.  The computers and other sensitive electronics also have additional cooling systems. 

     The loss of the bustle-mounted APU, however, merely brought back the problem of high fuel consumption.  GDLS designed a gas turbine 15kW APU (called a UAAPU – Under-Armor Auxiliary Power Unit) that is so much smaller in size that it can fit under the SEP’s armor, on the right rear side in a space made possible by rearrangement of the SEP’s fuel tanks (and deletion of one of them).  Budget shortfalls stopped this APU installation for nearly ten years, but in the interim, a possibly better solution was found – banks of advanced, compact batteries that fit in the same space that the gas turbine APU used.  These batteries can provide power for the SEP’s systems for about 8 hours, a period in which even an APU-equipped SEP would burn about 600 liters of fuel.  The SEPs also have a regulator system for the batteries, as a problem would often crop up with earlier Abrams tanks where the batteries would get ruined due to overcharging.  The regulator system allows the batteries to be charged up only to their maximum capacity.  Once the battery system was available, no SEPs were supposed to actually get the gas turbine APUs, and those that did had the APUs were supposed to have them replaced with the battery system instead.  Unfortunately, budget problems have intervened, and the less-expensive UAAPU units have ended up equipping almost all of the SEP fleet.  The cost of the APU (or the battery system) is fuel capacity – it’s taking the space normally occupied by one of the Abrams’ fuel tanks.  The entire M1 series have four fuel tanks, but the loss of the fourth fuel tank in the SEP costs the SEP 231 liters of fuel capacity.

The M1A2 SEP 2 Abrams III

     Known in the US Army by monikers like the “Electric Tank,” “Digital Tank,” and the “Digital Abrams,” the SEP 2 features an enhanced version of the Blue Force Tracker BMS, limited internet connectivity (normally to a unit intranet), Improved computers, satellite radios and phones, and improved normal radios., These computer, Blue Force Tracker, communications, and other computer improvements are assembled into a special operating system known as the COE (Common Operating Environment), an open-architecture that is designed for projected and possible upgrades in the future – even those still on the drawing board.  The electrical system is beefed up to handle the increased electrical workload. The SEP 2 also has improved frontal and side protection, largely in the form of a relatively thin layer of graphite-encased DU.  From the exterior, the most obvious alteration is the mounting of a CROWS station in front of the commander’s hatch; this is normally armed with an M2HB and M240 combination, but sometimes an M2HB/Mk19 combo is mounted.  The loader’s machinegun is retained, but AV2 gun shields wrap around the loader’s hatch, with a bullet-resistant glass panel in the front portion of the shield.  The loader’s hatch has been equipped with a skate mount around the hatch, but due to the constraints of other parts of the top of the turret, traverse is limited to 265 degrees, primarily to the left, front, and rear of the tank.  The CROWS station, of course, can be aimed, fired, and loaded from under armor, with sighting systems being provided as a part of the CROWS station. Before modification, the M1A2s to be modified are basically rebuilt from top to bottom, to what the Army calls “zero-miles condition,” essentially one step short of new, mechanically, electrically, drive-train-wise, and suspension-wise. The SEP 2 is capable of firing some new rounds (at the time) that earlier Abrams tanks were unable to, such as the M829A3 Kinetic, M1028 Canister, and M829A4 Advanced Kinetic Energy round. (Training rounds have also been developed to simulate the M829A3 and A4.)

     The US version of the Israeli Trophy APS was tested on the SEP 2, though none were operationally fitted with the system.

The M1A2C Abrams IV

     Originally known as the M1A2E1 and then as the M1A2 SEP III, the M1A2C was originally supposed to be an M1A2 SEP 2 with upgraded electronics, communications, an L/55 gun barrel, and a diesel engine.  However, as its long development went along (aside earlier upgrades), the longer gun and diesel engine fell out of the mix, and the M1A2C became sort of “SEP 2+”  The M1A2C mostly took the features of the SEP 2 and improved them, adding larger disk storage for its computers, a satellite radio able to use DoD satellites that are still classified, improved the internet connectivity (though still in an intranet) which can access more intranets, up to three simultaneously. The COE was improved to eliminate all-too-common crashes (though the COE is quick to reboot, a crash at the wrong time could be fatal for the tank or other units).  The electrical system was again beefed up, and the gunner’s and commander’s keyboards are full-sized instead of being miniaturized keyboards. .  The electronics were replaced by ones that are easier to upgrade. The fire control system includes the ability to operate with programmable ammunition. The optics include 2^nd Gen CCD day/night cameras, which can observe the exterior of the tank, the surrounding terrain, and provide a magnified view of objects within 30 meters of the vehicle. The CROWS station now had an M2HB/Mk 19 combo as standard, and the fire control and visual augmentation of the CROWS was improved.  M1A2s which did not have the “zero-miles” rebuild got it before modification into the M1A2C.  The Trophy APS/PPS system was installed as standard on the M1A2C, along with an EW system which jams radio-guided ATGM and PGM, has a 25% chance of jamming the fuzes of ATGM, PGM, and even rocket-propelled grenades.  It also is 95% likely to jam IEDs, roadside bombs, and actual military demolition charges which are actuated by radio or sensing the M1A2C’s radio or magnetic emissions; if the explosives are within 30 meters of the M1A2C, they are likely not to go off, even if that remote signal is by wire. The new version of the battery APU provides 15kW, and provides less of an IR “hot spot”, both due to insulation and the actual operating temperature of the batteries.

     Perhaps the most exciting upgrade on the M1A2C is its capability to control, and possibly launch up to four light UAVs and receive their input, as well as pass the information to other properly-equipped vehicles (primarily the Stryker series at this point).  (The stats below include four RQ-11 Raven drones.) The M1A2Cs engine has been upgraded to the AGT-1500 Tiger, which has reduced fuel consumption.  The M1A2C package adds lugs for ERA on the glacis, the slope under the glacis, the turret front and sides, the hull sides, and the front 25% of the turret.

     Most projected upgrades can be integrated into the M1A2C.

     By 2025, M1A1 SA’s in US service are to be upgraded to M1A2Cs.  A special configuration version of the M1A2C, called the M1A2X, is being offered for sale to Taiwan to counter PLA Type 99As, but there is little information about this version – too little to even hazard a guess about its capabilities at the time at which I write this (June 2019).  It is known that the DU inserts are replaced with tungsten carbide inserts.

The M1A2D Abrams IV

     Formerly known as the M1A2 SEP 4, the M1A2D centers around computing, fire control, and night and day vision upgrades to the M1A2C, enough upgrades to make it a new variant of the M1A2.  It has all of the features of the M1A2C, but more so – the computers, for example, are more powerful, have an upgrade of the COE, and larger hard drives that are solid-state instead of the traditional rotating disc hard drives.  This makes the hard drives better able to deal with the bumps from off-road and high-speed driving, as well as the firing of weapons.  The hard drives therefore don’t need the heavy shock absorbers of the M1A2C’s hard drives, though there are less substantial shock absorbers, for the hard drives as well as the rest of the computer system.  Ventilation for the computers is also given more attention, and a small amount of the air conditioning is bled off to cool the computer system.  The CCD cameras are in color instead of black and white, except when operating in night vision mode.  The commander’s and gunner’s sights are now day/night advanced FLIRs, with a range of over 10 kilometers, and with a telescopic component.  Also added are some meteorological sensors, which not only can give information over the intranet, but help with gun accuracy. Laser warning and detection receivers have been improved, and have a greater range.  Smoke grenade launchers (those for general obscuration) are movable and able to throw smoke in the best direction possible; the number of smoke grenade launchers have also been increased to 16, and can be loaded with chaff or APERS grenades if desired.  The M1A2D is able to use the new XM1147 Advanced Multipurpose round, which is a programmable round.  The laser rangefinder has triple normal range, and is accompanied by a laser designator of nearly 9000 meters range.  The battery APU has been strengthened and now delivers 17.5 kW, as some tankers found that the older battery APUs did not last as long as advertised.  Modular applique armor is added to several faces, and the M1A2D has the customary lugs for ERA as well as mounts for cage armor and other mounts to make TUSK systems easier to mount.  The APS has been modified into a v2 standard (called Trophy v2 or MAPS – Modular APS), with sharper and faster radar and radio resolution along with more countermeasure rounds.

     First M1A2Ds will be available in 2021 in limited numbers, with full-scale modifications (starting with older vehicles) to begin in 2022.

The M1A3 Abrams V

     Basically a step and a half beyond the drawing board, the M1A3 is being designed with projected OPFOR tank technology in about 2030-2040 in mind.  As such, the specifications of the M1A3 are highly in a state of flux, mostly in its armament and fire control systems.  It does take the M1A2D as a base, but there are several concepts for use on the M1A3, all of which may or may not be used on the M1A3.  The US Army still projects the need for a heavy tank into the 2040s, even though transporting them by air is becoming more and more problematic.  Essentially, the Army still feels that there will be a need for a heavily-armed and armored behemoth in the near future, at least, and that the Abrams’ successor vehicles will also include a heavy tank among them. (It should be noted that this is becoming less and less of a prevalent view, particularly with the advent of low-pressure 105mm and 120mm guns, lighter, denser, and more compact modular composite armor panels, stealth vehicle designs, APSs, and advanced applique armor such as MEXAS.)

     The M1A3 will center around its main armament.  This may be a 140mm low-pressure gun, a 120mm ETC gun, a conventional 120mm gun with an L/55 cannon barrel, or perhaps even sticking with the current L/44 120mm M256A1, relying on improvements and fire control and ammunition.  (Because of these possibilities, I included all three in the stats below.) If the L/44 or L/55 120mm guns are used, their barrels will likely be replaced by barrels with lighter alloys and composites technology. As stated above, the core of the M1A3 will be based on the M1A2D, carrying improved versions of its fire control, computers, intranet, satellite communications, Battery UUAPU – just about every major system will be improved in some way, including the CROWS module.  The turrets, if equipped with the 140mm or ETC gun, would be modified; though the version with the 140mm gun will have to be modified to an extent to keep a decent basic load of ammunition, the ETC gun variant will have to sport a heavily-modified turret, including armored tanks for the liquid propellant of the gun and mechanisms for injection of the propellant into what would have to be a liquid-sealed breech, a new ammunition ignition system, a different ammunition rack for the ammunition, and possibly blow-out panels for the liquid ammunition propellant tank. And also note that while the ETC gun would require special versions of normal 120mm rounds, it can also fire two rounds every phase, due to the lighter rounds (as they have no propellant charge in them).

     Another component looked at for improvement is the suspension.  The Abrams does tend to produce a rather bouncy ride cross-country, and there have been some injuries when the Abrams is moving at a fast clip cross-country.  This would be alleviated by keeping the front and rear shock absorbers in position, but replacing them with L3 hydropneumatic suspension units.  The number of shock absorbers would be increased from two to three, with the additional absorber being placed one roadwheel ahead of center; even four shock absorbers have been talked about, citing the M1-series’ increasing weight.

     Minor features would include a wider and wrap-around bustle rack and waist-high handholds for infantrymen or others hitching a ride on the tank. There would be heat dampening for the exhaust (always an Abrams weak point), and the exhaust for the interior ventilation system, air conditioner, Overpressure system. An indirect fire sight and fire control software would allow the M1A3 to operate as ad hoc artillery if necessary, especially with the use of Extended Range Cannon Ammunition (ERCA) and the XM360 LCCT (Large Caliber Cannon Technology) rounds. This will allow fire beyond the line of sight (Beyond LOS).

     And of course, there is already an M1A3 SEP being talked about…

For the New Iraqi Army: The M1A1 SA

     Notes: The “SA” stands for “Situational Awareness,” and refers to the extra vision devices over the standard M1A1 that the M1A1 SA is equipped with.  (The M1A1 SA is also known as the M1A1AIM.) This includes a 2^nd Generation FLIR for the gunner, a standard FLIR for the commander on his CITS, and a thermal imager as a backup camera for the driver.  It also includes extra vision blocks on the cupola for the commander, and one extra vision block for the loader at the rear of his hatch (in addition to the three wide-angle vision blocks to the front and right side). The laser rangefinder for the gunner is matched to the extreme range of his gun.  An internal APU is installed, the same one as on the M1A2. The M1A1 SA also has an air conditioner installed, though this takes up further room in the bustle rack.  The M1A1 SA has a rear slave receptacle installed in addition to the front slave receptacle. Though the M1A1 SA lacks a BMS, it includes screens and electronics to give the commander, gunner, and driver information about the vehicle state appropriate to their positions, with the commander having the most information.  The driver has GPS for navigation with inertial navigation backup.  The TIGER variant of the M1A1’s engine, installed on all other M1 series tanks, including those of other countries, facilitates this vehicle state information.

     Now, the most dramatic changes and improvements to the M1A1 SA.  The Iraqi M1A1 SA does not have the DU armor inserts of US M1A1 HA and HA+s, and armor is somewhat less than on a standard M1A1.  The M1A1 SA will also not have lugs for ERA. Text messages and email may also be sent and received. The M1A1 SA is equipped with the TUSK kit (see below).

     The US originally asked the Iraqi Army to equip itself with cheaper Russian exports.  But, it is believed, the Iraqis wanted the M1A1 SA to use as a deterrent to Turkey.  It does raise the spectre of M1-on-M1 action if Iraq ever has designs on the Saudi oil fields again, though Saudi variants of the M1 are essentially M1A2s, though without TUSK modifications; they are, however, M1A2s (without DU armor inserts), and should be able to defeat their Iraqi counterparts. 

     In addition, the US temporarily modified several marques of M1A1s into M1A1s into sort of an M1A1 SA+ model, enhancing the M1A1 SA into a version with the computers, electrical system, fire control, and communications gear of the M1A1(D), along with a CROWS station in front of the commander’s hatch and the loader’s gun shields of the M1A2 SEP version of the Abrams.  This was a short term, temporary modification, a sort of stopgap for M1A1s that did not receive the digital upgrades of the M1A1(D) version.  Some later made their way to the new Iraqi Army as command tanks, but most “M1A1 SA+” vehicles were shortly thereafter modified into the various marques of M1A2s

The “M1A1 SA+”

     Essentially a melding of the M1A1SA and the M1A1HA+(D), the M1A1 SA+ (a strictly unofficial designation, but one often used by its crews) was, as stated above, a temporary upgrade for M1A1s, to “hold the fort” until they could be further modified into the various variants of the M1A2. The M1A1s. if they did not already have the DU armor of the HA+ model, were brought up to that standard. .The digital modifications of the M1A2(D) were applied to the base M1A1 SA, along with a beefed up electrical system, the deletion of a fuel cell, and the installation of the battery APU (UUAPU). Finally, a CROWS station like that of the M1A2 SEP was added to was added in front of the commander’s hatch, armed with an electrically-fired M2HB/M240 combo which can be aimed, fired, and reloaded from under armor.  The AV2 all-around gun shields around the loader’s hatch, with the skate mount, were also added to the M1A1 SA+.

The TUSK Kit

     Based on experience in Iraq (especially in urban warfare and close combat), the US Army has designed the TUSK (Tank Urban Survivability Kit).  The origins of the TUSK were field modifications by individual Abrams crews and by their parent units (at various levels).  Many of these modifications were standardized and improved, producing the TUSK.  The TUSK can be added to any Abrams series tank (and some other vehicles), whether in part or using the entire kit.  The modifications are designed to enhance survivability of the crew and tank, as well as help the M1 operate more efficiently with attached infantry.  The TUSK modifications give the M1 lugs for ERA on the side skirts (which have proved quite vulnerable to RPG rocket penetration), louver-type spaced armor for the turret sides, slat-type armor for pre-detonating shaped charges on the rear of the tank, screens to prevent Molotov cocktail-type weapons from pouring into the engine, armored gun shields for the loader’s machinegun, and a remote weapons station for the commander’s machinegun so that he may aim, fire, and use his night vision for his machinegun while inside the protection of the tank.  The RWS used on the commander’s station (a variant of the M151 Protector CROWS used on the ICV version of the Stryker) also allows for the substitution of the M48 variant of the M2HB with a Mk 19 grenade machinegun, M240B GPMG, M249 SAW or standard M2HB machinegun.  The TUSK RWS (currently designated the XM101 RWS) includes a daylight video camera, its own thermal imager, and a fire control system that includes a laser rangefinder, a small ballistic computer, and armament stabilization (providing the commander a total +3 rangefinder modification to hit rolls).

     The loader’s machinegun mount is also modified with bracket for a “clip-on” thermal camera.  At the rear of the vehicle is a field telephone-type device to allow infantrymen on the ground to communicate with the tank crew, while using the tank as cover (this was common on World War 2-era tanks, but hasn’t been so since).  The modifications are designed to be able to be accomplished by second-echelon maintenance troops in the field, without the tank having to go back to a maintenance depot for modifications

     I have put stats for the add-on TUSK package (since it can be added to any M1).

Active Protection for the Abrams

     The US Army is also looking at the future deployment of a “hard-kill” APS (Active Protection System) for the Abrams and some other vehicles.  This is a system similar to the Russian Arena or Drozd, or the Israeli Trophy and Iron Fist, using a buckshot-like burst of large-caliber balls or fragments, or a small missile that explodes near the incoming projectile to the same effect, to destroy incoming ATGMs and rockets.  A set of sensors (short-range radar, laser-based, IR-based, or any/all of the above) detects these threats and automatically launches the countermeasure weapons, sometimes also launching smoke or flares to further confuse the incoming missiles and hide the protected vehicle.  US deployment of a hard-kill APS (Originally a system called “Quick Kill”, developed by Raytheon, was to be used, but a US-built version of the Israeli Trophy APS is to be used instead) has been the subject of much controversy – most of the Army brass originally wanted to simply buy the Israeli Trophy system and license-produce it; but they were overruled by Secretary of Defense (at the time) Donald Rumsfeld and some of the generals in charge of procurement of new systems for the Pentagon, since they favored a new system under development (and still under development) by Raytheon.  Congressional hearings have been and are still being held, due to charges to charges of graft, corruption, and kickbacks (i.e., bribes) being paid to Rumsfeld and the generals involved by Raytheon).  Raytheon’s hard-kill APS system is said to be far more complex, yet less effective, and has been plagued by repeated delays and cost overruns; current estimates have it going into service no earlier than 2012, and many military experts place it in service in 2016 or later.  Meanwhile, there is a growing movement in the Pentagon and Congress to go ahead and adopt the Israeli Trophy system, either while Raytheon’s APS is under development or in place of it.  As of May 2008, US vehicles are still not being protected by an APS.

     That said, the US Army is doing experimentation and limited combat-testing of a “soft-kill” APS (using the sensors mentioned above and an array of countermeasures) is ongoing.  Collectively known as the M1A2 P31 modifications, the current experiments and test are based on M1A2 and M1A2 SEP tanks, and add automatically triggered laser dazzlers and countermeasures (called the VIDS system; in game terms, laser-guided missiles are one level more difficult to hit with, and those using laser rangefinders against the protected vehicle must make a Difficult: INT roll to get a proper range if the VIDS is operating). The laser can also be used (manually) to attempt to temporarily blind an enemy gunner (Difficult:INT; range 2000 meters). The VIDS also includes a laser sensor that triggers the VIDS system.  An IR sensor is also included; this activates an IR jammer to decoy heat-seeking missiles (in game terms, most fire-and-forget ATGMs are one level harder to hit the protected vehicle with, unless the missile description states that it does not use IR guidance).  The IR sensor can also trigger IR-obscuring smoke and flares if needed.  An electro-optical jammer is used confuse missiles using MCLOS and SACLOS wire-guided missiles; at short ranges (about 500 meters), it can also confuse the actual guidance units of the ATGM launchers themselves as well as laser designators (as this is an automatic system, such jamming has a base roll of 14 to succeed).  The P31 program also includes modifications to the Abrams to lower the IR signature and noise levels of the tank.  The P31 modifications add launchers for 32 additional flares and 32 additional IR-obscuring smoke grenades.

Export Models

     Export models of the M1 series usually have some differences from the ones used by the US.  Though M1s of various models were tested in several countries who wanted to replace older tanks with state-of-the-art tanks, the first export customer for the Abrams was Egypt.  The Egyptian M1A1 contract was for base M1A1s, without the later upgrades or the DU mesh armor improvements.  The original size of the Egyptian M1 fleet was to be 755 M1A1s, but they recently have received permission (along with GDLS) to begin a modernization program for their M1A1s – they will be modernized to full M1A2 SEP standards (but see the note on their armor below), and in addition the Egyptians will also buy an additional 250 M1A2 SEPs that have been rebuilt from M1A1s, for a total M1A2 SEP fleet of 1005.  (The Egyptians have sort of a partial license for M1 production – the Egyptians produce most of the hull, turret, and power pack components themselves, but they are closely overseen by GDLS personnel.  In addition, the Egyptians are not permitted to produce or maintain the special armor components of their M1s – these are made at GDLS’s Lima Army Tank Plant in Ohio, and damaged parts of the special armor sections are sent back to Ohio for repair and/or replacement.)

     Saudi and Kuwaiti M1A2s are for the most part the same as standard M1A2s, but are equipped with air conditioning units as well as APUs, both of which are manufactured in Saudi Arabia.  (The air conditioners are said to be much better than those on the M1A2 SEP.)  Their IVIS systems and computers are the same as those used in the M1A2 SEP.  Kuwaiti and Saudi M1A2s are almost always seen with mine plows installed, though it is not a permanent installation and can be removed.  The fire control system is to a lesser standard (what has been left out has not been revealed). Maintenance it carried out in Saudi Arabia, except for the special armor, and GDLS also monitors the maintenance carefully.

     As far as the Egyptian, Kuwaiti, and Saudi M1A2s go, there are a lot of conflicting rumors (even among reliable sources) that the M1A2s used by those three countries do not have a DU mesh layer in their armor packages.  I have not been able to find any definitive yes or no on the DU mesh for the Middle Eastern M1A2, but I can think of a number of reasons why the US might not want Middle Eastern customers to have large amounts of depleted uranium available.  (And I’ll leave it at that to [hopefully] tame the flame emails…).  I have been able to find out that the US and most Western European arms manufacturers will not sell DU penetrators to most Middle Eastern countries, though the Saudis are apparently able to obtain them through “other means” (most likely Russia and former Soviet republics or the Chinese).  In the charts below, I have some versions of the M1A2 and M1A2 SEP listed as “Egyptian” and “Saudi/Kuwaiti (M1A2S and M1A2S SEP).”  Those entries account for the possibility that these countries may have versions of M1A2 without DU mesh armor inserts.

     The latest export customer for the M1 is Australia.  The Australians chose the M1A1 to replace their aging AS-1 Leopards; their first M1A1s arrived in Australia in September of 2006, and a total of 59 were bought and deliveries are now complete.  (At the same time, Australia also bought a small fleet of support vehicles for their M1A1s, consisting of M88A2 Hercules ARVs from the US and the German MAN TGA HET [Heavy Equipment Transporter].  The MAN TGA HETs are to be license-produced in Australia.)  The Australian version of the Abrams, designated the M1A1 AIM SA (the “SA” standing for “Situational Awareness”), is essentially a “fully loaded” M1A1 with all the refurbishments, modifications, and updates available to the M1A1(D) and the AIM XXI rebuild program.  In addition, the M1A1 AIM SA is equipped with an inertial navigation system to supplement the GPS navigation system, and the updated FBCB2 system that equips the newest versions of the M1A2 SEP.  The M1A1 AIM SA will burn diesel fuel instead of JP-8, though this required no modifications to the engine, and M1A2 AIM SA tanks retain the multi-fuel capability. Except for the commander’s machinegun, the machineguns on the M1A1 AIM SA are standard MAGs instead of the American M240 versions.  Australian AIM SAs do not use the bustle-rack 8kW APU of the M1A1, instead using the battery APU of the M1A2. Australian M1A2s are currently being upgraded to the M1A2C standard, with DU armor inserts.

     Early rumors suggested that the Auastralian M1A1 AIM SA did not use DU mesh inserts in its armor package.  (What the Australians did not buy were any rounds using DU penetrators – though since they have standard M256 guns, their M1A1s are quite capable of firing ammunition with DU penetrators.) The M1A1 AIM SA’s were delivered in desert sand paint, though I have not been able to find out what finish they are now wearing.  The Australian crews were trained for about two years at Camp Pendleton in California by the US Marines in the use of the M1A1 – the Marines were reportedly quite impressed by the Australian crews’ proficiency even before training commenced, and even learned some interesting new combat tactics from the Australians.  In addition, some of the Australian modifications to their M1A1 tanks are being given a serious look for inclusion into USMC M1A1s, after the Marines saw the additional capabilities of the M1A1 AIM SA.

     Most export Abrams are also equipped with radios that are used by the rest of the customers’ armed forces; in addition, the software, gauges, and controls display the language appropriate to the customer (there are unconfirmed rumors that even the Australian M1A1s have software, gauges and labels that use Australian-dialect spellings of words and even Australian jargon!).

Minor Variants

     A minor variant of the M1A1, the M1A1KVT (Krasnovian Variant Tank) is employed by the OPFOR at the National Training Center at Ft. Irwin; these are older, generally little-upgraded versions of the M1A1 that have been turned into VISMODs of the newer generation of Russian-made tanks with the addition of sheet metal, fiberglass, plastic additions to alter their external shape.  They remain combat-capable vehicles, and their modifications can be easily removed if combat service is necessary, or the KVT could actually go into combat still sporting the modifications.

     The M1A1 AIM adds a thin layer of additional DU armor to the glacis, turret front, and turret sides.  In addition, they were among the first vehicles that were rebuilt to bring them back to “zero miles” condition, and the Thermal Imager for the gunner is replaced by a FLIR viewer.  Telescopic sight’s magnification is doubled, and may work with the FLIR. At the rear of the tank is a field telephone allowing accompanying infantrymen to communicate with the tank’s commander.  Perhaps the biggest modification is the addition of FBCB2 and a Blue Force Tracker system (though without the vehicle state computer), and a thermal imager has been added to the commander’s sight for the M48. Most M1A1 AIMs did not last long, and few of them actually made into combat, as the M1A1 SA modifications were available soon thereafter, and many of the M1A1 AIMs went directly into M1A1 SA modifications from the M1A1 AIM modifications.

     M1A1 SA (Moroccan): Designed for the Moroccan Army, this is simply an M1A1 SA/AIM which does not have the DU inserts of the standard M1A1 SA.

     M1A1 FEP (Firepower Enhancement Package): This is simply an M1A1 SA with minor modifications for it’s role as a USMC tank, such as roadwheels of aluminum with vulcanized rubber tires, tracks or non-corrosive steel and vulcanized rubber track pads, and different radios, including a very long-range AM radio for communicating with ships offshore.  It is for the most part otherwise like an early Marine M1A1, but has a little more electronics.

     M1A1 AIDATS: Essentially an M1A1 FEP built on the Late USMC M1A1 base with a commander’s FLIR instead of a thermal imager, a CITS system, a color CCD day camera for the front and rear. It also has an additional layer of DU armor. Neither the FEP or the AIDATS was built in high numbers, due to budgetary constraints, but about 5% of USMC M1A1s are actually FEPs, and another 5% are AIDATS.

     M1 TTB (Tank Test Bed): Experimental only, this version had a variant of the M256 120mm gun in a casemated turret, along with an M2HB coaxial and another M2HB at the commander’s position.  It is the only hatch on the turret, and it is in a sub-casemated position.  The crew is reduced to three, and they are in the front of the tank above the glacis, with the driver in the center, commander on the right, and gunner on the left. All tank controls are downlinked to these positions.  The gun is fed by an autoloader, with ammunition selected, aimed, and fired by the gunner or commander.  As stated, it was experimental only, with three prototypes being produced.  The stats below are for a fully developed version; the actual TTBs are for the most part stripped of anything not necessary for the tests. The TTB is probably the source of Frank Chadwick’s M1A3 Giraffe, a fictional variant of the M1, and you should refer here to the M1A3 Giraffe entry for stats on the TTB.

     M1A2-K: 786 vehicles, most of Kuwait’s M1A1S fleet, are to be upgraded to what is essentially the M1A2C standard, with Arabic lettering on controls and software, and French-made radios instead of US-made radios.  They also have the TUSK kit installed as standard. The Saudi M1A2S v2 is also essentially the same tank, without the TUSK kit.  They have no special statting below.

     M1 CATTB: The CATTB (Component Advanced Technology Test Bed) was a version of the M1A1HA that tested advanced technologies that appeared on later models or may appear in future versions.  The vehicle centered around a new lightweight gun made or light advanced steel alloys and composites, similar to the possible gun on the future M1A3. The CATTB was equipped with an autoloader and advanced fire control electronics, the electronics and fire control did in fact surpass those of the (D) models, though to tell the truth, they were prone failure and wonky behavior.  The CATTB also tested an early version of a vehicle state computer, GPS navigation with a mapping module, and embedded modules to provide data from the vehicle’s systems. As the gun saved a considerable amount of weight, the CATTB was equipped with a heavier armor suite that was enabled by the lighter gun, allowing the CATTB to not weigh much more than a standard M1A1 of the time despite the increased armor.  The CATTB prototypes were used to test various technologies and then converted back to standard M1A1s of the period.

     M1 Thumper: The Thumper (Thumper was a nickname given to the vehicle during testing, and never the vehicle’s official name) was tested armed with the 140mm XM291 ATACS smoothbore cannon.  The Thumper has a longer turret, with the bustle enlarged to accommodate the larger 140mm rounds and a mechanical autoloader.  The armor was about equivalent to the M1A2, even though the Thumper is basically a modified IPM1.  The Thumper was essentially a Cold War project and testing stopped when the Cold War ended. 

     Recently, an M1 that looked like the Thumper was seen on a rail car in Texas going west; its destination was unknown, but some cell phone pictures were snapped of it, and it definitely looks like the Thumper.

     Twilight 2000 Notes: In the Twilight 2000 timeline, about one-quarter of the US Army’s M1s at the time of the Twilight War were M1A2s, and only about 5% were M1A2 SEPs.  The bulk of US Abrams were M1A1s, but less than a quarter were of the M1A1(D) type; most of these M1A1(D)s were used as command tanks, and a very small number were used as scouts.  A common addition to Twilight War M1A1s in US units was a CITV.  The AIM XXI program simply never got off the ground. 

     The Egyptian plant making the export version of the M1A1 was put out of action early in the Twilight War – not by the Israelis, as you might think, but by the Libyans.  The Egyptians ended up with only 202 M1A1s before the destruction of their plant.

     Some 112 M1A1s were also sent to China in sort of a “Lend-Lease” program.  These Chinese M1A1s were equivalent to early-model M1A1s (and in some cases, actually were early-production M1A1s).  Their Russian opponents at first thought the US had sent troops to China until they found out about the exported M1A1s.

     The Saudis only received 31 of the M1A1 order, the Kuwaitis got a grand total of 3, in the Twilight 2000 timeline.  The Australian M1A2 AIM SA never existed in the Twilight 2000 timeline.  None of the possible future improvements listed above were done in the Twilight 2000 timeline, and no sort of active protection system was ever considered.  The TUSK never existed as a factory-manufactured kit, but the same sorts of modifications were carried out in part or whole on virtually any sort of military vehicle in the Twilight 2000 timeline.

     Merc 2000 Notes: The M1A2 was also sold to the Turks.  Their M1A2s have the full M1A2 armor package and fire control system, but are equipped with M1A2 SEP-type IVIS systems.