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 M-551 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).

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 a 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 M-2HB, M-240 machinegun, or other compatible weapons. The gunner has a roof-mounted M-36E1 sight that is normally a day/night sight with magnification and a ballistic computer, but an enhanced version of the same system (the M-36E1 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 M-240C 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 M-1 Abrams. The gun controls and the ballistic computer are modified versions of those found on the M-60A3.

The Stingray’s suspension is based on that of the M-109 self-propelled howitzer, with roadwheels of the same type as those on the M-41 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 M-109 SP howitzer. Access to the power pack is designed to simplify maintenance and if necessary, replacement as one unit.

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 M-1A1 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.

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 M-8 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 M-8 AGS-type add-on armor packages are referred to below in the same way as the M-8 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 M-9 light tank (or M-9E1 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 M-8 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 M-1 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.

Notes: In many ways an improved version of the M-46, the M-47 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 "M-47" and ordered into low-rate initial production; the generals also felt that the M-46 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 M-48 Patton tank. Small quantities of the M-47 are used by Greece, Italy, Pakistan, Somalia, South Korea, Turkey, and the former Yugoslavia, but only Spain and Iran still use the M-47 in any large numbers (as a tank; large numbers have been converted to ARVs).

The M-47 used a modified version of the M-46’s hull. (The original design called for a new hull as well, but the expedient of using a modified M-46 hull was done to hurry the M-47 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 M-46 had infrared headlights, for use with the then-new night vision equipment available for tanks.

The turret of the M-47 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 M-2HB mounted on a pedestal mount. The commander also had a periscope for vision while buttoned up or longer-range vision. Primary armament was an M-36 90mm gun, with an M-1919A4E1 as a coaxial machinegun. A further M-1919A4E1 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 M-46’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 M-46A1, but the bow machinegunner had no auxiliary controls.

Though the US military was no longer using the M-47 by 1969, BMY came out with an upgrade kit for the M-47 for allies still using the M-47; this was called the M-47M. The modifications used as many components of the M-60A1 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 M-60A1, and the last pair of roadwheels were moved back about 8 cm to properly seat the engine. The M-47’s shock absorbers were replaced with those of the original M-60, 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 M-47M 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 M-60A1. The coaxial machinegun was replaced with an M-219 or a MAG.

Since then, several other countries have developed or fielded other upgraded M-47 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 M-47’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 M-47s such as the M-47M, or as found under national listings.

Notes: The predecessor of the M-48, the M-47, 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 M-48 Patton began development almost parallel with the M-47. The M-48 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 M-48 began in late 1950. The M-48 was the only version of the M-47/M-48/M-60 series to be officially called the Patton, though the M-47 was informally called the Patton as well.

The M-48 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 M-48 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 M-48 would be given a heavier main gun in the future, and the large turret gave the M-48 room for expansion.

The original M-48 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 M-48 were still being ironed out. Actual full-service issue did not occur until over a year later. When finalized, the M-48 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 M-48 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 M-48 was the 90mm M-41, an update of the M-47’s 90mm M-36 gun. The M-41 was tipped with a cylindrical blast deflector, and featured a quick-change gun tube. Originally, the M-48 was to have an M-2HB ranging machinegun to the left of the main gun and an M-1919A4 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 M-2HB 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 M-2HB. 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 M-2HB 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 M-47. 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 M-48 had a ravenous appetite for fuel. The suspension was considerably beefed-up over the M-47, 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 M-47’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 M-48A1 fixed a number of problems with the M-48, but perhaps the primary change was the commander’s cupola. The commander’s machinegun was moved inside the new M-1 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 M-1 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 M-48’s ravenous appetite for fuel, and it seems straight out of Soviet doctrine. The M-48A1 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 M-48A1. 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 M-48 was primarily issued to units in the US, the M-48A1s were generally the first M-48s issued to US units overseas, particularly in Europe.

Despite the improvements of the M-48A1, 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 M-48A1. 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 M-48 and M-48A1 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 M-48s and M-48A1s). 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 M-48A2 a rougher ride, and this got worse the faster the M-48A2 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 M-48A2C. 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 M-48A2’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 M-48A1s were modified to the M-48A2C standard. The coaxial machinegun was replaced with the M-37, a version of the M-1919A4 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 M-48A2 and A2C became the most-produced M-48 variant.

The M-48A3 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 M-60 was not going to be produced in large enough number to replace the M-48 for a few more years, so the M-48A3 was to fill the "tank gap." Most M-48A3s were upgraded M-48A2Cs, M-48A2s and M-48A1s, but some were new production.

The changes from the M-48A2C almost resulted in a new tank itself. Many of the improvements were done by using components that were also used on the M-60. The engine was replaced by an AVDS-1790-2 diesel engine along with an appropriate transmission. The coaxial machinegun was replaced by the M-73 machinegun. The situation with the cramped M-1 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 M-48A2s 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 M-48A3 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 M-2HB 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; M-48s also often became heavily sandbagged on the turret and hull.

The M-48A4 was a possibly interesting idea that was never actually deployed, but is interesting enough that I couldn’t resist. When the M-60A2 proved to be a failure, many in the Pentagon felt that the M-60A2’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 M-60A2 turrets with improved systems were mounted on M-48A3 hulls. Though the combination worked at least as well as the M-60A2, and in fact the systems weren’t quite as nightmarish from a maintenance standpoint, the fact remained that the M-60A2’s firepower package was simply unnecessary; the M-48A3 itself was a better tank than the M-48A4, and there were other fire support options in the inventory that made the M-48A4 superfluous for that purpose. After less than a year of testing, the idea was dropped.

The M-48A5 was the final major US upgrade for the M-48 series. The US found themselves in a curious situation in the early 1970s: The M-60A2 and MBT-70 have been costly failures, the M-60A3 was not yet ready, and hundreds of M-60s and M-60A1s 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 M-48A5, which was essentially an M-48 with a lot of the components of the M-60A1 and some from the upcoming M-60A3. Though the M-48A5 was originally to be an interim design, Chrysler found there was a ready market overseas for the M-48A5, and production of upgrade kits and new production M-48A5 exceeded expectations. The M-48A5 was not ready, however, until 1976; by then, the only US units to receive the M-48A5 were National Guard, Reserve, and tank battalions of the 2^nd Infantry Division in Korea.

The engine of the M-48A5 was a variant of the M-48A3’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 M-48A5 incorporated a new commander’s cupola, called the Urdan cupola (though early-production M-48A5s still used the M-1 cupola with a riser). The Urdan cupola was not equipped with a machinegun; instead, M-60D 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 M-2HB, 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 M-1 cupola on a riser.

Perhaps the most dramatic modification to the M-48A5, however, was the replacement of the 90mm gun with the M-68 105mm rifled gun fitted to the M-60 series. First done on M-48A3s, and then done almost en masse by the Israelis on their M-48A3s, this proved to be a relatively easy upgrade for the M-48A5; the M-48A3 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 M-48A4’s turret is hit, roll an additional 1D10. If a 1-3 is rolled, the "hit" is actually a miss.

**The M-48A4 cannot move when firing a Shillelagh missile, and must remain stationary until the missile hits (or misses) it’s target. If the M-48A4 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.

Notes: Originally a meant to be a simple improvement of the M-48 series (the test vehicles for the M-60 were in fact designated the M-48A2E1 at first), the M-60 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 M-60 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 M-60 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 predecessors used the same name, this is not an official M-60 appellation.

Development of the M-60 began in early 1954. From the beginning, a diesel engine was decided upon to power the M-60, as the M-48A2 that the M-60 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 M-60 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 M-68 (the M-68 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 M-60s used the same fire-control suite as the M-48A2.

Originally, the M-60 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 M-60 was RHA instead. The original turret was essentially identical to that of the M-48A2, 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 M-48A2. This turret was equipped with the then-new M-48 .50-caliber machinegun to same space (original plans were for the use of the M-2HB). 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 M-48 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 M-48A2C, 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 M-60 was armed with the M-85 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 M-60s were sent from the factory with M-2HBs on a pedestal mount atop the cupola, as the M-85 was undergoing developmental problems; the M-85s 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 M-73 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" M-60s were built before being replaced in production by the M-60A1 in 1962.

The M-60 was a decent tank for the time, but it could have been better. Development of the M-60A1 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 M-60, 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 M-85 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 M-60A1 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 M-35 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 M-219 machinegun, which was unfortunately about as prone to failure as the M-73. Though at first not included, virtually all M-60A1’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 M-60A1 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 M-60A1 production would continue for over 20 years, with many modifications here and there. The US Marines were using M-60A1s equipped with ERA as late as Desert Storm.

And now for something completely different…

The M-60A2 was an attempt to dramatically increase the firepower and long-range gunnery of the M-60 series. The genesis of the M-60A2 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 M-60A2 and the vehicle that became the M-551 Sheridan were developed in tandem. Turret candidates for the M-60A2 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 M-60A2 did not reach full operational status until 1973, and only 540 were built (mostly modified from M-60A1s).

The resulting M-60A2 – well, you can tell that the hull is an M-60A1s, 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 M-60A2’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 M-60A2 was armed with the M-162 152mm gun-missile launcher. As the primary accent of the M-60A2 was to fight at long range with the Shillelagh, and a long 152mm gun tube would have been quite heavy, the length of the M-60A2’s gun tube was a mere 2.67 meters – only an L/17.52 gun. The M-162 gun was designed to fire only the MGM-51C 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 M-162 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 M-60A2 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 M-51 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 M-48 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 M-73, but was soon replaced by the M-219. The loader had an M-37 periscope in his hatch. The driver’s position in the M-60A2 was essentially the same as in the M-60A1. The turret of the M-60A2 also had eight smoke grenade launchers, with the grenades launched electrically from the commander’s cupola.

The M-60A2 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 M-60A2 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 M-60A2, 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 M-60A2 was no longer necessary. Though a majority of M-60A2s were converted back into M-60A1s or into M-60A3s, some were made-over into AVLBs or mine-roller vehicles.

By the late 1960s, there had been many technological and automotive advances in tank design. The M-60A1 was becoming an outdated design compared to the tanks of the US’s NATO allies, particularly the German’s Leopard 1. The M-60A1 was the recipient of several incremental upgrade programs, culminating in the M-60A3, 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 M-85 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 M-60A1, 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 M-60A1 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 M-60A1’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 M-60A3 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 M-21 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 M-21 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 M-60A3(TTS). The M-60A3 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 M-239 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 M-240C. 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.

In the late 1980s, GDLS developed an upgrade package for the M-60, both for export and for existing US M-60A1 and A3 tanks (at the time, whether or not the Army National Guard and US Marines would receive their M-1 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 M-60 users (most of which are buying newer-design tanks), GDLS is still offering the upgrade.