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Cold War US Engineering & Support

Medium Recovery Vehicle M88

U.S.A. (1961)
Armored Recovery Vehicle – Aprx. 3000

As a result of thicker armor, and the ever-increasing caliber of weaponry, tanks and armored vehicles in the aftermath of the Second World War became bigger and heavier. With the introduction of heavier vehicles throughout the Cold War, tanks would continue to gain weight and girth. Existing recovery vehicles based on the M4 Sherman, such as the M32 and M74, were reaching the end of their usefulness and proved inadequate to rescue a tank such as the 50 ton (44 tonne) M48 Patton III or the titanic 65 ton (58 tonne) M103 heavy tank.

In answer to the need for a new, more powerful recovery vehicle, the Chrysler Corporation, builders of the M103, produced a companion recovery vehicle for operation with the Heavy Tank. This was the Heavy Recovery Vehicle M51, itself based on the M103. This found use in the United States Marine Corps, the major users of the M103, but the US Army was still in need of a support vehicle for its medium tanks. Bowen-McLaughlin, Inc. came forward with a design for a ‘Medium Recovery Vehicle’ in 1954, based on the automotive components of the M48 Patton III medium tank.

After 7 years of development, the finalized vehicle was approved. It would be designated Medium Recovery Vehicle M88. It would enter service in 1961 and through various upgrade programs remains in service with the US Military to this day as the M88A2 ‘Heavy Equipment Recovery Combat Utility Lifting Extraction System’, otherwise known as ‘HERCULES’. The M88 also continues to serve in the armed forces of various other nations, from Australia to Egypt.

M88A1 in the Gulf War, 1990-91. Photo: Military Today

Development

In October 1954, the desired characteristics of a ‘medium recovery vehicle’ were outlined by the United States Ordnance Committee. The project received the designation T88, and three pilot vehicles were ordered. In December of that year, a conference was held at the Detroit Arsenal (DA) to review designs for the T88. DA themselves and Bowen-McLaughlin, Inc (BM) put forward designs, two from DA, and one from Bowen-McLaughlin, which was reviewed first.

Concept 1: Bowen-McLaughlin’s design was based on a drastic conversion of the USA’s latest medium tank, the M48 Patton III. The conversion would necessitate the complete removal of the turret and the curved ‘beak’ that formed the bow. This was to provide ample space for a fixed, armored cab to be built at the front end of the hull. Hull extension would also be required to provide enough room for a new, more powerful engine. It was also suggested that the vehicle’s overall width be reduced from the original 12 feet (3.6 meters) to 11 feet 6 inches (3.5 meters). It was hoped that the addition of the narrower 27 inch (68cm) wide tracks of the M47 Patton II would prove sufficient for this. An ‘A’ frame boom forged from tubular steel was placed atop the armored cab capable of supporting 25 tons (23 tonnes). It was also equipped with a 50 ton (45 tonne) capacity winch. It had a single spade stabiliser at the front and two spade stabilisers on the rear that were positioned via cables. The cab would be constructed of 1 inch (25 mm) armor, with a ¾-inch (19 mm) thick roof. The cab would contain the vehicle’s four-man crew.

Bowen-McLaughlin’s initial design for the T88. The similarities between this and what would become the M88 are clearly visible. Photo: Hunnicutt Patton

Concept 2 & 3: DA’s designs were similar to BM’s. They utilized the same basic chassis with a cab at the front and an ‘A’ frame boom mounted atop it. On Concept 2, the cab would have a much lower profile and thinner, ½-inch (12.7 mm) armor. The cab on Concept 3 would be taller and have ¾-inch (19 mm) thick armor. Both designs had a four-man crew, but contained two extra seats for additional personnel. Also, the suspension differed slightly, being a ‘flat-track’ type. This is a suspension without rollers where the track return is supported by the road wheels. Such suspension was used on tanks such as the Soviet T-54. Concepts 2 and 3 were also designed with jettisonable external fuel tanks to increase the ARV’s operational range.

Findings

After considering the three designs, the conference held at Detroit Arsenal concluded that Bowen-McLaughlin’s design had many admirable features. However, doubt was cast over the conversion of the M48 tank. It was thought, as the M48 was the USA’s front line tank at this time, that there would not be enough tanks available for conversion. It was also suggested that it would probably be easier to build a completely new vehicle instead of trying to modify an existing hull. Although an M48-based vehicle was rejected, it was recommended that the T88 be equipped with the features installed on the Bowen design and follow a base tank design to permit maximum interchangeability between them, and standardization of component parts.

The Pacific Car & Foundry Company and the Food Machinery & Chemical Corporation put a spanner in the works by suggesting that all winching and lifting operations be undertaken from the rear of the vehicle. On the BM design, it was done from the front of the vehicle. Mock-ups of the two rear-end focused designs, and Bowen’s front end design were prepared. The mock-ups were reviewed by Continental Army Command (CONARC) who wholeheartedly supported the front end focused vehicle to maximize operator visibility.

After all of these pre-development trials, Bowen-McLaughlin’s design came through on top. In October 1955, authorization was granted for the manufacture of three pilot vehicles. A Contract was signed with BM in April 1956 to start work on constructing the pilots.

A Doomed Project?

A number of delays that arose during the manufacture of the pilot vehicles cast a shadow over the future of the entire T88 project. A meeting held at the Ordnance Tank Automotive Command (OTAC) in January 1957 noted that just 90% of a single vehicle had been constructed. At this time, the biggest threat to the T88 was a new medium tank project that was taking shape to become the USA’s next front line medium tank, the T95. It was suggested that the current T88 design be dropped in favor of a new design utilizing parts from the T95. This would’ve received the designation T88E1.

However, since the M48 was the most numerous tank then in service in the US Military, it was suggested that an interim recovery vehicle be produced by simply making an add-on kit for the M48A2.

T88 at Aberdeen Proving Grounds, 6th February 1958. Photo: Public Domain

The eventual delivery of the T88 pilot vehicles and subsequent tests did not do much to save the future of the recovery vehicle. The vehicles were designed to be powered by the Continental AVI-1790-8 (AVI: Air-cooled, V-configured, Fuel Injected) engine. Producing 580 horsepower, it was thought that the 1790-8 engine would provide enough power to straight-pull the 52 ton (47 tonne) M48 Patton. In tests with the pilot vehicles, however, it was found that it had a relatively mediocre performance. As the weight of tanks was projected to increase over the following years, it was decided to replace this engine with the more powerful AVSI-1790-6 (AVSI: Air-cooled, V-configured, Supercharged, & Fuel Injected.) which produced 690 horsepower. This was coupled with the XT-1400 transmission which was already installed on the M51 Heavy Recovery Vehicle. This was the most powerful propulsion setup available to the Ordnance Department at the time of the tests and a meeting held in October 1958 concluded that it should be installed in the pilot T88s for the remainder of the trials.

Serialisation and Production

In February 1959, approval was granted for the production of three production pilots with the new powertrain. At the same time, the T88 received the official designation and serialization as the ‘Medium Recovery Vehicle M88’.

Photo of one of the early production vehicles taken at APG in 1961. Photo: Hunnicutt Patton

At this point in time, the T95 had been replaced by the XM60 as America’s future front-line tank. As such, the need for a recovery vehicle in the weight and power-class of the M88 was once more highlighted. The M88’s initial designers, Bowen-McLaughlin, Inc (now known as Bowen-McLaughlin York Company – BMY) were granted a contract in 1960 for the full-scale production of the M88. This contract lasted until 1964, and in that period 1,075 vehicles were produced.

Design of the M88 in Detail

The production model of the M88 is 27 feet 1½ inches (8.27 m) long, 11 feet 3 inches ft (3.43 m) wide, and 10 feet 6 inches ft (3.23 m) tall. A Continental AVSI-1790-6A engine, running through an Allison XT-1400-2 transmission powered the M88. This engine produced 980 horsepower, propelling the 51 ton (46 tonne) recovery vehicle to a top speed of 26 mph (42 km/h). The vehicle consists of an armored cab at the front supported on an elongated M48-like running gear. The vehicle rolls on six road-wheels attached to a torsion-bar suspension with the drive sprocket at the rear and idler at the front. The idler wheel was of the compensating type, meaning it was attached to the closest roadwheel by an actuating arm. When the roadwheel reacts to terrain the idler is pushed out or pulled in, keeping constant track tension. The return of the track was supported by three rollers.

M88 ‘Hell’s Half Acre of the US Army in Vietnam. The vehicle’s four-man crew sit atop their positions on the roof of the cab. You can see five of the vehicles road wheels in this photo as it has somehow lost the sixth. Photo: SOURCE

The cab extended back to roughly the center of the chassis, just over the fourth road-wheel. The cab was constructed of 1 inch (25mm) armor on the front and sides, with a ¾-inch (19mm) thick roof. The front plate is slightly sloped backward. There were headlights on the left and right cheeks of the cab. On later models, smoke dischargers were added above these. There are large hatches on the left and right side of the cab, positioned just over the third roadwheel. The A-frame crane arm is attached on pivoting joints at the forward edge of the roof and folds backwards into a travel-lock on the engine deck. At the front of the vehicle is a dozer blade, roughly the same width as the vehicle. Behind the cab is the engine, the fenders of which are part of the same casting as the sides of the cab. This rear section of the vehicle is primarily used for the stowage of spare parts and towing/recovery equipment, pioneer tools, spare road-wheel halves, drive wheel sprockets, rollers, track links and towing bars. As the exhaust pipes from the engine emerged in the center of the engine deck, a cowling system was constructed around them that takes the gasses and smoke, and vents them off the rear of the vehicle. There is a plate under the ventilation grills that deflect the gasses and smoke skywards.

The exhaust cowlings at the back of the M88. Photo: Jochen Vollert/Tankograd Publishing

Crew and Their Positions

A four-man crew operates the M88. This consists of the Commander (positioned in the center of the cab), Rigger (behind the Commander), Mechanic (front right) and the Driver (front left). Atop the Commander’s position was a vision cupola. It is here that the vehicle’s only armament can be found; a single Browning M2 .50 Cal (12.7mm) heavy machine gun for defensive purposes. There is a smaller hatch behind the Commander’s was for the Rigger. Both the Driver and Mechanic have vision blocks molded into the upper-front plate. They each have their own hatch, and three vision blocks per-position. The Driver has an extra rotating periscope built into his hatch.

A good deal of equipment is stored within the crew compartment. This included: At least 1 rifle (either M14 or M16), 3x M72 LAW rocket launchers, 2x jerry cans of water, 2x jerry cans of oil, 2x fire extinguishers, 1x bolt cutter, 2x vehicle jacks (one of 11 ton/10 tonne & one of 27 ton/25 tonne capacity), boxes of .50 Cal (12.7mm) ammunition, and 3x toolboxes.

Recovery Equipment

There are three major pieces of recovery equipment present aboard the M88. These are a Winch, an ‘A’ frame boom, and a spade. As a recovery vehicle, the winch – A Pacific Car & Foundry manufactured Type U90B – is the main piece of equipment. The winch drum is located in a compartment below the cab at the front of the vehicle. The cable is around 200 feet (61 meters) long and 1 ⅕ inches (32mm) in diameter. It exits the vehicle via a small port in the front plate of the cab and has a maximum capacity of 45 tons (41 tonnes). There is a roller under the port to reduce wear on the cable. The winch is wound/unwound via a hydraulic motor with a winding speed of 42 feet (12.8 meters) per minute.

The M88’s main winch. On the left, the empty void where it is placed, on the right, the winch itself. Photos: Marcus Bach/Tankograd Publishing

Second to this winch, is the ‘A’ frame boom and accompanying hoist winch. The boom consists of tubular steel frame with a hoist at the end. The boom is raised and lowered via hydraulics found on the left and right side of the hull. The boom arm has a forward-reach ranging between 4 feet (1.22 meters) and 8 feet (2.44 meters). At 4 feet of reach, maximum lifting height is 25 feet (7.66 meters), at 8 feet, this is reduced to 22 feet (6.87 meters). Lift is provided via winch and cable. The winch is located below the crew compartment with the cable traveling through a tunnel in the cab and emerges from a porthole the roof. The port is protected by a winch cable access door with integral rollers to reduce wear. The cable, which is 200 feet (61 meters) long and ⅝ of an inch (16mm) in diameter, then stretches up to the pulley at the top. The cable has a maximum capacity of 25 (23 tonnes). When raised, the boom is supported by stayline cables which are anchored on the left and right rear of the engine deck.

An M88 uses its boom-hoist to list an M113 on a flatbed trailer. Vietnam, January 1971. Photo: Olive-Drab.com

With its 45 ton (41 tonne) capacity, the main winch is responsible for the recovery of heavy vehicles such as medium tanks, like the M60 or M48. With roughly half the capacity of the winch, the boom is mostly used for the recovery of lighter wheeled vehicles or light armored vehicles like the M113 Armored Personnel Carrier (APC). It is predominantly used for the hoisting of heavy equipment, such as cannons or mine plows, and automotive components, such as engine and transmission units.

Located at the front of the vehicle, the hydraulically operated dozer blade, also known as the spade, has a number of roles. When the boom crane is deployed and lifting, the spade is utilized in a similar fashion to outriggers on a commercial crane. The blade is lowered underneath the front of the hull so far that the first set of road-wheels are almost touching the back of the blade. The blade is roughly the same width as the hull at 11.25 ft (3.43 m), and can, of course, also be used for light-bulldozer work, such as carving out hull-down positions for tanks, digging gun emplacements, route denial (creating and filling anti-tank ditches), improving bridge approaches, and leveling uneven ground. When not in use, the spade is stored in a horizontal position just above the idler wheels.

M88A1 ‘Grocery Getter’ of the 1st Battalion, 36th Infantry Regiment. This photo shows the dozer blade at the front of the M88 in stabilizing position. Photo: Oliver Kroh/Tankograd Publishing

The M88 also carries a number of pieces of towing equipment. These include spare pulleys, tow-bars, towing chains and towing cables. This equipment is stowed on the left and right flanks of the engine deck. The M88 has a towing capacity of 45 tons (41 tonnes), and can safely tow at speeds up to 13 mph (21 km/h).

An M88A1 of the 1st Battalion, 7th Field Artillery Regiment tows an M577A2 Mobile Command Post, Germany, 2000. Photo: Clemends Niesner/Tankograd Publishing

Upgrades and New Models

M88A1

Although the M88’s Continental AVSI-1790-6A engine was powerful, it had a high rate of fuel consumption. A full, 445 gallon (1,684 liters) tank gave the M88 a range of 201 miles (322 km). In the 1960s, the Military began to upgrade their vehicles to have more economical diesel engines. In 1972, BMY received a contract to produce a diesel-powered version of the M88. A prototype was ready by 1973, and it was designated the M88E1. The new engine was the same as the one installed on the M60 tank. This was the Continental AVDS-1790-2DR (AVDS: Air-cooled, V-configured, Diesel, Supercharged), a turbocharged 12-cylinder V engine. This new engine produced 750hp, this was less than the 980hp of the original engine but it granted increased torque and was thus extremely beneficial to straight-pulling and towing operations. It also granted an increased range of 300 miles (483 km). A new, Allison XT-1410-4 transmission was also installed with the engine. A new hydraulic pump was added that allowed the boom and winches to operate should the vehicle’s engine fail. In 1975, the M88E1 was officially serialized as the M88A1. Of the original production of 1,075 vehicles produced by BMY, 878 were built to A1 with production ending in 1982. In 1989, 2,167 new M88A1s were built. The M88A1 entered service with the US military in the late 1980s.

An M88A1 taking part in a training exercise to flip an overturned Marine Corps M60A3 tank. Gulf War, Operation Desert Shield, December 1990. Photo: inetres.com

New Tank = More Power

The original purpose of M88, and then M88A1, was to support the M48 and M60 tanks. When these tanks entered service, they had an approximate weight of 45 tons (41 tonnes) each. By the time these vehicles reached their final forms of M48A5 and M60A3, they weighed 49 tons (44 tonnes) and 52 tons (47 tonnes) respectively. This already exceeded the recommended maximum weight capacity of the M88. Then, the M1 Abrams arrived. The M1 Abrams main battle tank – named after the WWII General Creighton Abrams – had a base weight of 54 tons (49 tonnes) and, over its service life, this weight would only increase. It was clear that the M88 and M88A1 would only be grossly over-burdened by the M1. As such, in 1982, a requirement was drafted to produce an improved, more powerful version of the M88.

M88AX

Bowen-McLaughlin-York had foreseen the appearance of heavier tanks and the logistical issues they would cause the M88 and M88A1. In 1982, the company started work on improving the M88A1. The resulting vehicle was designated the M88AX. It received a new AVDS-1790-8DR air-cooled, turbocharged, 12-cylinder V diesel engine which produced 1,050 hp. This was coupled with an Allison XT-1410-5X transmission. Ballast was added to the vehicle to bring its weight up to 59 tons (53 tonnes). From 1985 onwards, the M88AX was put through a series of trials, during which the AX reached a top speed of 35 mph (56 km/h) and was able to tow an M1A1 Abrams at 25 mph (40 km/h). Although it did not enter service, lessons learned were passed on to the next program.

The M88AX in testing pulling an M1A1 up an incline. Note the weight blocks added to the front and sides of the vehicle. Photo: BMY/Tankograd Publishing

M88A1E1

In 1987, BMY was granted a contract to produce five improved M88A1s, following the outlines of the M88AX. These vehicles were given the designation of M88A1E1 Improved Recovery Vehicle (IRV). Improvements also included a new hoist boom constructed from hollow, square-profile steel beams, replacing the old tubular steel boom. It also included an improved main winch with greater pulling capacity. Running parallel to the A1E1s development was a new Armored Recovery Vehicle based on the M1 Abrams. In summer 1988, trials were held between the M88A1E1 and a prototype M1 ARV. The winner of the trials was the M88, and additional funding was granted to Bowen-McLaughlin-York to allow quick development to production. In 1989 however, the M88A1E1 project was canceled due to budgetary limitations.

The M88A1E1 Improved Recovery Vehicle (IRV) photographed in the late-1980s. The similarities with the later M88A2 are clearly visible. Photo: BMY/Tankograd Publishing

M88A2 & M88A2 HERCULES

In October 1991, the program to develop a new version of the ARV was reinstated. BMY was contracted to continue development up to 1993 when the existing prototypes from previous trials were reworked and put through extensive trials. In 1994 BMY was contracted to produce the new vehicle but due to further budget limits, it was decided to upgrade the M88A1 rather than build a whole new vehicle. In 1997, after tests, this new upgraded version of the M88 was designated the M88A2, it shared a few of the features tested on the M88A1E1. It is also known as the M88A2 ‘Heavy Equipment Recovery Combat Utility Lift & Evacuation System’, poetically acronymed as ‘HERCULES’ (this is also known as a ‘Backronym’). The conversion of M88A1 to M88A2 was a joint effort undertaken by United Defense LP (now part of BAE) and Anniston Army Depot.

The M88A2 ‘Heavy Equipment Recovery Combat Utility Lift & Evacuation System’, also known as ‘HERCULES’. Note the boom arm now constructed of square steel pipes, the added armor on the sides and front, the two-piece hatch, and the armored side-skirts. Photo: BAE Systems

The M88A2 was far improved over the M88A1 model. It can lift heavier loads with its reinforced 35 ton (31 tonne) capacity hoist boom and can pull heavier loads with its 70 ton (64 tonne) capacity main-winch. The main winch now had a 321 foot (98 meter) long, 1 ⅖ inch (35mm) diameter cable. A new auxiliary winch was added on the front of the vehicle, under the port where the main winch cable emerges. This auxiliary winch has a capacity of 3.3 tons (3 tonnes) with a 654 foot (199) meter cable. The M88A2 is powered by a Continental (now L-3 Propulsion Systems) AVDS-1790-8CR, air-cooled, turbocharged, 1,050 hp, 12-cylinder V diesel engine coupled with an Allison XT-1410-5A transmission. This gave the ARV more brute force power than the previous power pack, but only improved the top speed by 4 mph (6 km/h). As well as automotive and recovery equipment upgrades, the A2 also received armor upgrades. The entire superstructure was covered in an extra layer of armor plate. Huge, one-piece plates were added to the flanks of the vehicle that covered the whole of the cab and sides of the engine compartment. New two-piece hatches were built into these plates to replace the old one-piece hatches of the earlier M88 models. Another plate was added over the front of the cab, with extra small plates placed in front of the Driver and Mechanic’s positions. Finally, the M88A2 was given armored side skirts comprised of eight separate panels, all hinged to allow access to the running gear. The thickness of this armor is unknown, but it is said to be immune to 30mm Armor-Piercing rounds. In some cases, smoke dischargers were added to the front of the vehicle as well.

The M88A2 HERCULES is now the dedicated companion and support vehicle to the M1 Abrams. It entered service in the early 2000s and continues to serve today. Production of the HERCULES continues today. In September 2017, the production of 20 new vehicles was ordered. In December 2017 a total of 775 vehicles were produced and delivered. Another 60 are expected to be delivered between 2018 and 2019, bringing the Army inventory to 835 M88A2 vehicles. Armored Brigade Combat Teams of the National Guard (ABCTs) are also now being equipped with the M88A2 HERCULES. Upon the completion of M88A2 HERCULES production, 237 older M88A1s will remain in use by non-Abrams equipped units.

An M88A2 HERCULES performing its duty as the support vehicle to M1A2 Abrams. Photo: SOURCE

Future: The M88A3

The M1 Abrams is set to get even heavier in the future with the increased addition of new, heavier modular armor packages. In 2015-2016, BAE Systems began work on a new version of the ARV, designated the M88A3. The vehicle will feature a number of upgrades, including the addition of a seventh road-wheel to increase stability, and hydro-pneumatic suspension that can lock. (Locking the suspension will grant greater stability in lifting operations, a similar system is used on Self-Propelled Guns (SPGs) to help absorb recoil). Currently, on the A2, a member of the crew has to exit the vehicle and place a wooden block behind the rear wheels to achieve the same result. In October 2018, at the AUSA (Association of the United States Army) exhibition of 2018, one of the first prototypes of this vehicle, which was simply a modified A2 featuring the added road wheel, was unveiled. Further upgrades planned for the A3 include the replacement of the A2’s 1,050 hp AVDS-1790-8CR engine with a 1,300 hp Caterpillar liquid-cooled diesel engine, and the installation of a new transmission based on that of the M1 Abrams. This version of the M88 remains in development.

The M88A3 prototype unveiled at AUSA 2018. Note the extra roadwheel. Photos: Shephard Media

Experimental Off-Shoot: The Counter Obstacle Vehicle (COV)

The ‘Counter Obstacle Vehicle’ or ‘COV’ was an experimental Combat Engineering Vehicle (CEV) based on the hull of the M88. The control cab was completely removed to make way for two digging arms on the left and right side of the vehicle. A large dozer blade that could also be used as a mine plow was added to the front. The vehicle would never go past the prototype phase, with the program canceled in 1986. Developments made in the program were, however, passed on to the M1 Grizzly, a project to build a CEV based on the chassis of the M1 Abrams.

The prototype ‘Counter Obstacle Vehicle’ also known as ‘COV’. Photo: BMY/Tankograd Publishing

Service

The M88 entered service in 1961, at first just with the M48 Patton equipped units of the US Army. At this point, the US Marine Corps (USMC) was still happy with its M103 based M51 Heavy Recovery Vehicle, and would continue to use them until 1977.
To go into detail about every combat situation the M88 found itself in would be an exercise in futility. Simply put, the M88 has served wherever the US Army has been deployed since 1961. We shall explore a few of its more famous deployments in the following sections. Perhaps its longest deployment was in West Germany with US forces. They were issued to all US tank units stationed in the country.

Civillians look on as an American M88A1 pulls the power pack of an M60A1 tank during Operation Carbine Fortress in Niederstetten, Germany, 1982. Photo: Manfred Garstka/Tankograd Publishing

The Vietnam War

Vietnam was the M88’s first combat deployment with the US Army. It proved itself invaluable in the dense, marshy jungles of the war-torn country. Such terrain was a headache for the tanks that easily became stuck. The M88 proved to be a life-line when recovering tanks and vehicles from these sticky situations. They also proved to be extremely useful in field-repair tasks, and in the preparation of terrain with the use of its dozer blade. While the M48 Patton was the main object of the M88s’ attentions, as it was intended, the ARV was also used in the support of lighter vehicles such as the M41 Walker-Bulldog light tank, and the M113 Armored Personel Carrier (APC). In Vietnam, the M88 would serve alongside the M51, its older, heavier cousin – which was still in service with the US Marine Corps – and the Light Recovery Vehicle M578.

A rather comical photo of two M88s lifting a fellow M88 of the 178th Maintenance Company, Dong Ha, Vietnam. Photo: 2nd Bat. 94th Art.

The Gulf War

By the 1990s, the newer M88A1 had entered service. At this point, the M48 Patton and M60 tanks had been largely removed from service in the US Army, with the heavier M1 Abrams Main Battle Tank taking its place. The US Marine Corps, however, continued to use the M60. Also, by this point in time, the USMC was now fully equipped with the M88 and M88A1. One of the first combat deployments of the newer model of the M88 was in the Middle East, supporting American forces in Operation Desert Shield, and the following Desert Storm, during the Gulf War of 1990-1991. The Gulf War was the M88’s first deployment in support of the M1 Abrams, as well as the M2 & M3 Bradley Fighting Vehicles.

M88A1s in Iraq during the Gulf War 1990-91. Photo: Wikimedia

Bosnia & Kosovo

The next deployments of the M88 would be to southeastern Europe. Between 1992 and 1995, they were deployed with the US contingent taking part in the War in Bosnia. Later, between 1998 and 1999, the M88 supported the armored sections of the US forces deployed to Kosovo during the war. They were also present to support US tank units that remained deployed as part of NATO’s ‘Kosovo Force’ known as ‘KFOR’.

An M88A1 and M577A2 Mobile Command Post of the 1st Infantry Division ‘Big Red One’ in Kosovo, June 1999. Here, the M88A1 has just pulled the powerpack of the M577. Photo: Carl Schulze/Tankograd Publishing

Afghanistan & Iraq

At the beginning of the 21st Century, American forces would once more see deployment in the Middle East. In 2001, the United States invaded Afghanistan in response to the 9/11 terrorist attacks. In 2003, this was followed by the invasion of Iraq. Afghanistan and Iraq was the combat debut of the newly upgraded M88A2 HERCULES in both US Army and USMC service, as the Marine Corps was now fully equipped with the M1 Abrams. The M88A2 did not just support the Abrams in Iraq and Afghanistan; from 2008, it was also the support vehicle of the Abrams-based Assault Breacher Vehicle (ABV). While here, the M88A2s were equipped with the ‘DUKE’ Electronic Countermeasure (ECM) system. This is a jammer that blocks signals to remote explosives or other devices to stop them detonating. Vehicles equipped with this system are identified by thick white antennas attached to the outside of the hull.

An M88A2 HERCULES follows an Assault Breacher Vehicle (ABV) of the Mobile Assault Company, USMC 2nd Combat Engineer Battalion as it enters the staging area for Operation Dynamic Partnership. The ‘DUKE’ antennas can be seen in this photo. Photo: Corporal Alejandro Pena

Exports & Foreign Service

The M88 was a great export success, seeing service with around 23 countries around the globe. Next to the USA, Egypt is the second-largest user of the M88. The Egyptian Army currently operates 221 M88A1s and 60-70 M88A2s. The M88A1s were second hand, but the A2s however, were manufactured in the US, with final assembly taking place in Egypt.

Germany was the next largest user, operating 125 M88A1s from 1966 to 1992. Here, the M88 received the resignation ‘Bergepanzer 1’. The M88 was a necessary acquisition by Germany as it had a large fleet of M47 and M48 tanks. In 1985, the began upgrading there M88s to A1 standard. They also began upgrading the onboard radios. Vehicles fitted with new SEM25/35 radios were designated the M88A1 GE. Some vehicles were upgraded further with SEM 70/80/90 radios. Other upgrades included the addition of smoke dischargers on the sides of the cab. These were designated M88A1 GE A1s. In 1992, the vehicle was largely replaced by the Leopard 1-based Bergepanzer 2 and Leopard 2-based Bergepanzer 3 Büffel.

A Bergepanzer M88 being towed by a Bergepanzer 2A2 in a training exercise in the 1980s. Both vehicles served in the Bundeswehr for many years, at some points side-by-side. Photo: Yves Debay/Tankograd Publishing

The M88 and M88A1 saw long service in Israel, with a number of M88s upgraded to A1 standard. As is common, the Israelis heavily modified their vehicles to keep them up-to-date. In the case of the M88, this included the heavy application of bar and slat armor to protect against RPGs (Rocket-Propelled Grenades) and shaped-charge ordnance. In addition, a large turret constructed from armored panels and bullet-proof glass blocks was installed over the commander’s position. The M88s are set to be retired in the coming years, and will be replaced by the Merkava-based Nemmera ARV.

Israeli M88 at Israel’s 70th Independence Day celebrations. Photo: Wikimedia Commons

Other international operators of the M88/M88A1 include Greece (fleet of 95 M88A1s), Pakistan (fleet of 52 M88A1s), Taiwan (fleet of 37 M88A1s), Austria (fleet of 35 M88A1s), Lebanon (fleet of 35 M88A1s), Turkey (fleet of 33 M88A1s), Jordan (fleet of 30 M88A1s), Israel (fleet of 25 vehicles, a mixed fleet of M88A1s and M88s brought to A1 standard), Brazil (fleet of 12 M88A1s), Morocco (fleet of 12 M88A1s), Portugal (fleet of 6 M88A1s), Tunisia (fleet of 6 M88A1s), Bahrain (fleet of 4 M88A1s), Sudan (fleet of 2 M88As), and Spain (1 M88A1).

The only users of the M88A2 HERCULES outside of the United States are Australia (fleet of 13 M88A2s), Egypt (fleet of 221 M88A1s & 60-70 M88A2s), Kuwait (fleet of 14 M88A2s), Iraq (20-30 M88A2s), Saudi Arabia (fleet of 20 M88A2s) and Thailand (fleet of 22 M88A1s & 6 M88A2s).

As Australia operates a fleet of M1A1 AIM Abrams Main Battle Tanks, it was necessary that they procure its intended support vehicle. Between 2004 and 2005, Australia ordered 7 A2s, which began to be delivered in 2007. In 2017, six more vehicles were purchased. As of 2019, the country operates 13 of the ARVs. The majority of the A2s serve with the 1st Armoured Regiment of the 1st Brigade in Darwin, where the largest force of Abrams is based.

M88A2 ‘Out on Bail’ of the Australian 1st Armoured Regiment, 1st Armoured Brigade. Photo: Gordon Arthur/Tankograd Publishing

In 2010, the Iraqi army requested the purchase and construction of the M88A2 HERCULES for their own use. Starting that year, eight A2s would be delivered with a second batch of eight following in 2012. Starting in 2010, Iraq began to receive a number of M1A1M Abrams as part of military aid, and currently operates around 140 of the tanks. To support these Abrams, a further quantity of M88A2s were also gifted. The Iraqi army currently operates 24 M88A2s.

The latest purchase of the M88 was by the Kingdom of Saudi Arabia who already had a large fleet of 50-60 M88A1s. In 2016, they procured 20 M88A1s and A2s with a plan for the Saudi Arabians to upgrade them to ‘HERCULES’ standard. It remains to be seen as to whether more countries will purchase the M88A2 in the coming years.

Conclusion

As a whole, the M88 is one of the longest-serving Armored Recovery Vehicles (ARVs) in the world and, quite possibly, one of the most successful in history.

During its 58 years of service, systematic upgrades have kept it in place as the backbone and lifeline of the United States military’s armored units. This ARV’s long service life shows no sign of coming to an end anytime soon, as the M88A2 HERCULES continues to provide support for the M1 Abrams until it is replaced by the M88A3. Likewise, the Abrams is projected to fight on for the foreseeable future, and as such will continue to be partnered with the M88A2.


The original Medium Recovery Vehicle M88 in a standard Olive Drab Livery. The standard M88 served with the US military from the late-1960s, to the late-1980s.  

M88A1 with A-frame boom raised in lifting position and hoisting an engine unit. The dozer blade is also lowered to provide support. With a new diesel engine, the M88A1 entered service just before the Gulf War, and would serve during the War in the middle east. The camouflage pattern is based on images of M88s from that time.

Bergepanzer M88A1 GE. The German Army fielded the M88 and M88A1 for a number of years, up to 1992 when it started to be replaced by Leopard-based ARVs. Note the smoke dischargers towards the front of the cab.

The M88A2 ‘Heavy Equipment Recovery Combat Utility Lift & Evacuation System’, otherwise known as the ‘HERCULES’, entered service in the early-2000s. It continues to serve today supporting the M1 Abrams. Note the added armor plate to the cab of the vehicle and the armored side skirts. Note also, the two-part door which replaced the original one-piece, and the square bars of the A-frame boom.

M88A2 ‘Out on Bail’ of the Australian 1st Armoured Regiment, 1st Armoured Brigade. Note the red Kangaroo motif on the side of the cab. Australia operates a fleet of  M1A1 AIM Abrams, and as such, starting in 2004, began purchasing M88A2s to support them.

These Illustrations were produced by Andrei ‘Octo10’ Kirushkin, funded by our Patreon Campaign.

Specifications (M88, M88A1 & M88A2 HERCULES)

Dimensions (L-W-H) 27 ft 1 0.5 in x 11 ft 3 in x 10 ft 3 in (8.27 x 3.43 x 3.12 meters)
Total weight, battle ready M88 & M88A1: 50 tons (50.8 tonnes)
M88A2: 62.5 tons (63.5 tonnes)
Crew 4 (Commander, Rigger, Mechanic, Driver)
Propulsion M88: Continental AVSI-1790-6A, 980 hp
M88A1: Continental AVDS-1790-2DR, 750 hp
M88A2: L-3 Propulsion Systems AVDS-1790-8CR, 1,050 hp
Transmission M88: Allison XT-1400-2
M88A1: Allison XT-1410-4
M88A2: Allison XT-1410-5A
Maximum speed M88 & M88A1: 26 mph (42 km/h)
M88A2: 30 mph (48 km/h )
Suspensions Torsion bars
Range (Fuel) M88 & M88A1: 280 miles (450 km)
M88A2: 200 miles (322 km)
Armament 1 x Browning .50 Cal. (12.7mm) M2HB Heavy Machine Gun
Recovery Equipment M88 & M88A1:45 ton (41 tonne) capacity main winch
25 (23 tonnes) capacity hoist winch
22.5 ton (20 tonnes) capacity A-frame boom
Hydraulic Dozer Blade
M88A2: 70 ton (64 tonne) capacity main winch
35 ton (31 tonne) capacity A-frame boom
3.3 ton (3 tonne) capacity auxiliary winch
Hydraulic Dozer Blade
Armor M88 & M88A1: ¾-inch (19mm) – 1 inch (25mm) around the cab.
M88A2: As previous, with extra 30mm Ammunition-proof plating
Production (All) Aprx. 3000

Sources

R. P. Hunicutt, Patton: A History of the American Main Battle Tank, Volume 1, Presidio Press
Carl Schulze, M88 Armored Recovery Vehicle, Tankograd Publishing
David Doyle, M88 Armored Recovery Vehicle Walk Around, Squadron/Signal Publications
Ralph Zwilling, In Detail/Fast Track #8: M88A2 HERCULES, Tankograd Publishing
www.army-technology.com
www.inetres.com
www.defesanet.com.br
www.defense-aerospace.com
www.upi.com (1) (2)
M88A2 2019 Selected Acquisition Report (PDF)
www.janes.com


Categories
Cold War US Engineering & Support

Heavy Recovery Vehicle M51

U.S.A. (1951)
Armored Recovery Vehicle (ARV) – 187 Built

As a result of thicker armor, and the ever-increasing caliber of weaponry, tanks and armored vehicles in the aftermath of the Second World War became bigger and heavier. Logistically, heavy vehicles are a nightmare for recovery teams. With the introduction of heavier vehicles following the end of the Second World War, these nightmares would only get worse for such teams. Their World War Two era recovery vehicles based on the M4 Sherman, such as the M32 and M74, were inadequate to rescue a tank such as the 42 ton (38 tonne) M46 Patton or the titanic 65 ton (58 tonne) M103 heavy tank.

The answer to this problem was building a new Armored Recovery Vehicle (ARV) based on the M103 itself. This vehicle would be designated as the Heavy Recovery Vehicle M51. It featured a powerful 45 ton (40 tonnes) winch and a large, traversable crane arm capable of lifting 30 tons (27 tonnes).

This new vehicle would enter service from 1956-58 but would have a relatively short service life, after being largely replaced in the early 1960s by the M48-based Recovery Vehicle M88. The M51 still saw active service though. This was mostly in the Vietnam War with the United States Marine Corps (USMC), but also in smaller conflicts such as the US Occupation of the Dominican Republic in the mid-1960s.

The Heavy Recovery Vehicle M51. Photo: Public Domain

Development

The M51’s development began in February 1951 with a design study to produce a recovery vehicle capable of lifting and towing the new, heavier vehicles that were coming into service. A proposed concept meeting these requirements was shown to the Army Field Forces (AFF) in April of the same year. Construction of a full-scale mock-up and two pilot models began in the summer. By August, the design was approved and it received the designation ‘Heavy Recovery Vehicle T51’. The two pilot vehicles were dispatched to take part in tests. Pilot Number 2 was sent to Fort Knox, Kentucky, for service tests, arriving in February 1953, while Pilot Number 1 was sent for engineering and endurance trials at Aberdeen Proving Grounds (APG), Maryland, in April.

Heavy Recovery Vehicle T51, the finalized design from 1954 to 1956. Note the original crane arm. Photo: Hunnicutt’s Firepower

In October 1953, the vehicle was officially standardized as the Heavy Recovery Vehicle M51. The Chrysler Corporation of Detroit, Michigan, builder of the M103 heavy tank, was handed the contract to build the M51 to a cost of around $150,000 (around $1.4 million today) per vehicle, about half the price of an M103 tank. The first production pilot began construction that month and was then tested at Fort Knox in March 1954. The first production vehicle, following the finalized design, was completed and released in August 1954. A total of 187 M51s were built by Chrysler between 1954 and 1955.

Rear view of the 1954/56 design. Note the original crane arm and the two separate outriggers on the rear. These were later replaced with a spade like the one at the front of the vehicle. Photo: Hunnicutt’s Firepower

After further tests, it was found that the design still needed some adjustments and modifications as there were a number of defects in the engine, transmission, crane booms and winches. As such, Chrysler produced a pre-modification pilot incorporating no less than 52 alterations. The program to upgrade the vehicles started in June 1956, with the final vehicles being completed in July 1958. Each vehicle cost $26,000 (around $240,000 today) to upgrade. It would seem that only 177 of the vehicles received the modifications. It is unknown as to what exactly happened to the outstanding ten vehicles. It is possible they were kept for spare parts, but they may also have been completely scrapped.

Base: The 120mm Gun Tank M103

The M103 heavy tank was one of the largest and heaviest armored vehicles to ever serve with the United States Military during the Cold War. It was also the last heavy tank to serve, albeit almost solely, with the Marine Corps, as the US Army did not completely accept the tank.

The tank featured a 120mm main gun, and armor up to 5.1 inches (130 mm) thick. The vehicle was powered by an 810hp Continental AV-1790 12-cylinder air-cooled gasoline engine, which gave it a top speed of 21 mph (34 km/h). A slightly different, more powerful version of this engine was used for the M51, however. This was the AVSI-1790-6, accompanied by an XT-1400-2A cross-drive transmission. This was a supercharged, fuel injection version of the AV-1790, granting around 190 more horsepower, bringing the power up to 1000hp. The acronym ‘AVSI’ therefore stands for ‘Air-cooled, V-configured, Supercharged, Injected’. The Diesel engine upgrade that was installed on the M103A2 was not needed on the M51 with this supercharged engine installed.

The tank’s weight was supported on seven road wheels attached to torsion bar suspension. The drive sprocket was at the rear while the idler wheel was at the front. The idler wheel was of the compensating type, meaning it was attached to the closest roadwheel by an actuating arm. When the roadwheel reacts to terrain the idler is pushed out or pulled in, keeping constant track tension. The only difference between the running gear on the M103 and the M51 was the return rollers. The M103 had six while the M51 had four.

Schematic of the M51 ARV. Photo: Hunicutt’s Firepower

Design of the ARV

The M103 hull is almost unrecognizable as the foundation of the M51. The turret was completely removed and the upper hull extensively reworked. The engine location was the same as the M103, this being in the rear half of the vehicle. The engine deck, for the most part, remained unchanged, apart from the addition of smaller items of recovery equipment such as towing bars. These were stowed on the left-rear fender.

A USMC M51 in Dong Ha, Vietnam, 1968. Towing bars are installed at the front of the vehicle. Note also the extended winch cable. Photo: Unknown Source

The armored ‘beak’ of the M103 and the Driver’s position housed within were removed with the ARV’s main and most powerful winch taking their place. A large, armored superstructure was built over the front portion of the hull which extended back to around the center of the turret-ring on the M103, splitting to accommodate the crane. This structure was of a welded construction and was made out of rolled homogeneous steel. The armor on the superstructure was ¾ of an inch (19mm) thick, enough to stand against heavy machine guns, small caliber cannons, and shrapnel. There was stowage around the outside for various pieces of recovery equipment. These included jerry cans, fire extinguishers and oxy-acetylene bottles for cutting.

The superstructure is where the M51’s four crew members would operate the vehicle. The crew consisted of a Commander (front and center), Driver (front left), Rigger (center right) and Crane Operator (right rear). The Crane Operator, as his name clearly suggests, operated the 30-ton (27 tonnes) capacity crane, located directly at the rear and center of the superstructure. The Rigger was responsible for ‘rigging’ tow cables and the crane to whatever vehicle was in need of recovery. There were doors on the left and right side of the cabin, with ladders on the outside that extended down over the tracks. This allowed easy access for the crew. The Commander had a cupola above his position, to which was mounted the ARV’s only weapon, a single Browning M2HB .50 Caliber (12.7mm) Heavy Machine Gun. This was used specifically for self-defense.

The finalized M51 ARV. Note the .50 Cal (12.7mm) ‘Ma Deuce’ machine gun mounted atop the Commander’s cupola. Photo: AFVDB

At the front and rear of the ARV were deployable stabilizers. These were used when the crane was in operation to keep the vehicle secure and to stop it from shifting on its tracks by lifting slightly off the ground. They performed the same role as ‘outriggers’ on construction vehicles such as backhoes, excavators and cranes. The forward stabilizer spade was also a shallow dozer blade. This could be used for light excavation work such as smoothing terrain or building up gun/tank positions. The rear stabilizer went through a few changes over the vehicle’s development. Initially, on the T51, two individual, manually operated jacks were installed on the rear armor plate. At the end of the jacks was a large diameter metal disc, used to spread the weight of the vehicle over a larger area. For the M51, these were replaced with a single hydraulically operated spade like the one on the front.

US Marine Corps M51 A43 ‘Jolly Green Giant’. On the right, it can be seen rendering aid to a USMC M48A2 Patton. Vietnam, 1967/68. Photo: Vince Streech.
.

Crane

The crane arm went through a few changes between the T51 phase and the 1956/58 modification. Originally, the crane consisted of a single arm with exposed cables and lacked the ability to extend. For the finalized M51 model, the cables were almost completely housed internally in the boom. The boom was mostly straight, lowering into a curve at the connection to the hull, and it also had a hump halfway along. This hump was necessary as the improved crane arm could extend about 4 extra feet (1.2 meters). This, however, meant that only half of the lift capacity could be achieved at 15 tons (13 tonnes).

This photo of M51 ‘Nadine’ of the 1st Marine Tank Division in Vietnam shows the crane at full elevation. Photo: SOURCE

The Crane was almost completely cable operated, with not a single piece of hydraulic equipment inside the boom arm. Everything from the crane elevation, extension, and raising of the hook was controlled by cables and winches. The only part of the crane controlled by hydraulics was its horizontal traverse and the winch drums. The crane could swivel 30 degrees to the left and 30 degrees to the right. This was achieved with a horizontally aligned hydraulic ram placed underneath the crane in the hull, directly where the center of the turret ring would be on the M103. To turn the crane over the right fender, the ram would be extended. To turn it over the left fender, the ram would retract.

A USMC M51 in Dong Ha, Vietnam, 1968. It is using its crane to hoist the barrel of an M53 Self-Propelled Gun. Photo: Unknown Source

Winches

The most powerful piece of recovery equipment installed on the M51 was its 45 ton (40 tonnes) capacity main winch. This winch was located internally, in the bow of the M51, where the Driver would be located on the M103. An armored door on the lower glacis protected the winch drum, and this was opened to allow its use.

The front of the M51. In this photo, we can see the large door on the lower glacis, behind which could be found the main 45-ton winch. On the left of the face of the superstructure is a smaller door. This is where the 5-ton auxiliary winch was located. Photo: Hunnicutt’s Firepower

There was also a 5 ton (4.5 tonnes) capacity auxiliary winch found high and right of the main winch, on the right side of the upper superstructure. This is also protected by an armored door, albeit smaller, which opened to allow access.

Service

The M51 would share the same fate as the M103 it was built upon. The United States Marine Corps (USMC) was more than happy with the vehicle, fully accepting it into service. The US Army, however, did not. This may be due to the fact that US Army tankers had no experience with the M103 type, so did not want to accept a vehicle based on it. The USMC, of course, did have experience with the M103. The US Army would instead adopt the M48/M60 based Recovery Vehicle M88, which began development in 1959 and entered service in 1961.

An M51 being reversed onto a landing craft at Dong Ha, Vietnam, 1967. Photo: Hunnicutt’s Firepower

The USMC would deploy their M51s in a number of theaters, including Vietnam, unlike its M103 cousin. They even served during the United States occupation of the Dominican Republic in 1965, during the Dominican Civil War. Unfortunately, no more is known about its time serving in combat zones.

An M51 assigned to B Company, 2nd Tank Battalion, 2nd Marine Division towing a Dominican L-60 Light tank during the US intervention in the Dominican Civil War, 1965. Photo: Ampersand Publishing Company/Hobbylink Japan

The USMC would eventually retire their M51s and follow the Army into adopting the newer M88 in 1977, outlasting the M103 by two years. Even now, both branches retain the M88 in its latest incarnation, the M88A2 Heavy Equipment Recovery Combat Utility Lifting Extraction System, otherwise known as ‘HERCULES’.

Conclusion

Much like its M103 brother, the M51 was very much an ‘ugly duckling’ of the armored vehicle world. It was rejected by the US Army, but found service in the Marine Corps where it proved itself versatile, reliable and popular with the crews and troops. A Marine Corps tanker who got his vehicle stuck in a ditch would certainly have wanted no other vehicle to come to his rescue.

A number of these Armored Recovery Vehicles do still survive today. One can be found at the American Military Museum in Los Angeles, another can be found at the 45th Infantry Division Museum in Oklahoma City, Oklahoma. Once more can also be found at Fort Benning, Georgia. This example is currently going through preservation.

Surviving M51 at the Aberdeen Proving Grounds prior to the Museum’s closure. Photo: Richard S. Eshleman


Illustration of the Heavy Recovery Vehicle M51. Note the ladder for the crew, the oxy-acetylene bottle behind the cab, and the out-riggers on the front and rear of the hull. Produced by Andrei ‘Octo10’ Kirushkin, funded by our Patreon Campaign.

Specifications

Dimensions (L-w-H) 33 feet 3 inches x 11 feet 11 inches x 10 feet 9 inches (10.1 x 3.76 x 3.2 meters)
Total weight, battle ready 60 tons (54 tonnes)
Crew 4 (Commander, Driver, Rigger, Crane Operator)
Propulsion 980hp Continental AVSI-1790-6 V12, Supercharged, Fuel injected
Transmission Cross-drive XT-1400-2A 3-Fw/1-Rv
Maximum speed 30 mph (48 km/h) on road
Suspensions Torsion bars
Armament 1x Browning .50 Cal. (12.7mm) M2HB Heavy Machine Gun
Recovery Equipment 30 ton (27 tonne) capacity crane
45 ton (40 tonne) capacity main winch
5 ton (4.5 tonne) capacity auxiliary winch
Dozer Blade
Armor 1 ½ inch – ¾ inch (38 – 19 mm)
Production 187
For information about abbreviations check the Lexical Index

Sources

Colonel Robert J. Icks, AFV/Weapons Profile #41: M103 Heavy Tank and M41 Light Tank (Walker-Bulldog)
David Doyle, M103 Heavy Tank, A Visual History of America’s Only Operational Heavy Tank 1950-1970, Ampersand Publishing Company/Hobbylink Japan
R. P. Hunnicutt, Firepower: A History of the American Heavy Tank, Presidio Press
Osprey Publishing, New Vanguard #197: M103 Heavy Tank 1950-74
www.historyofwar.org


Categories
Cold War US Engineering & Support

Armored Combat Earthmover M9 (ACE)

U.S.A. (1986)
Combat Engineering Vehicle – 448 Built

To put it simply, the Armoured Combat Earthmover M9, often just known as ACE, is a battlefield bulldozer. The vehicle is intended as a highly mobile, protected earth moving vehicle for combat engineers. It is a valuable support vehicle to armored, mechanized and infantry units. In combat operations, the M9 ACE can perform a number of tasks in support of friendly units. These include mobility (clearing a safe passage of blockages), counter-mobility (route-denial, the reverse of mobility tasks), and survivability tasks (constructing defensive positions). The M9 features a number of innovative features, such as a hydropneumatic suspension, a ballastable front end, and the ability to be amphibious.

The first vehicles entered service 1986, with the vehicle serving in most major operations with the United States Military ever since, most notably in The Gulf War (1990-1991) and The War in Iraq (2003-2011).

Despite all of their uses and features, the M9s were highly unreliable and, as such, loathed by the troops it was there to support. Hydraulic and mechanical failures have plagued the ACE throughout its service life. To try and salvage the tattered reputation of the vehicle, an extensive upgrade program began in 2014, and, for now at least, these upgrades keep the M9 in service.

Armoured Combat Earthmover M9 “ACE”. Photo: militaryimages.net

Development

A search for a battlefield engineering vehicle that was capable of earthmoving tasks had been sought since the mid-1950s. Initially, this led to the development of a vehicle known as the All-Purpose Ballastable Crawler, or ‘ABC’, that was developed in 1958. This nomenclature was later changed to Universal Engineering Tractor, or ‘UET’. One of the features of the UET was that it could also carry troops in the empty ballast bowl via fold-out seats. This feature was later dropped, however.

What would go on to become the M9 appeared in 1977. The Engineer Laboratory at Fort Belvoir, Virginia, with added assistance from the International Harvester Co. and Caterpillar Inc., was responsible for the initial development of the vehicle. Pacific Car and Foundry were given a contract to build no less than 15 prototypes, based on the cumulative design of the three co-developers. These were completed by the early 1980s. After some additional improvements to the design, a contract for full production was signed with Bowen-McLaughlin York (BMY, now owned by BAE Systems). In total, 566 vehicles were ordered to be built. Due to budget cutbacks, however, only 448 of the vehicles were acquired. The first vehicles entered service in 1986, with production running into 1991.

The prototype Universal Engineering Tractor (UET) demonstrates its digging capabilities. It is unknown where or when the photo was taken, but the location is likely that of the BMY proving grounds. Photo: Wisconsin History

General Specifications & Features

The M9 is not your every day 50 ton/tonne, earth-scraping, lumbering brute of a bulldozer. In fact, it is the exact opposite. The ACE is lightweight at around 16 tons (16.3 tonnes), allowing it to be highly mobile. This light weight is partly due to its welded and bolted steel and aluminum construction. The M9 is 20 feet 6 inches (6.25 m) long, 10 feet 5 inches (3.2 m) wide, and 9 feet 6 inches (2.9 m) high. The ACE’s lightness and compact size allow it to be air transportable by C-130 Hercules, C-141 Starlifter, C-5 Galaxy or C-17 Globemaster cargo aircraft. It also allows it to be amphibious. In ideal conditions, the vehicle can travel in water at 3 mph (5 km/h) using the rotation of the tracks to propel it. This was a feature that mostly went unused and consequently, most vehicles have had the amphibious equipment removed or it has simply gone unmaintained.

Early production model of the M9 ACE. Photo: Presidio Press, Sheridan

Only the rear-most portion of the vehicle is armored. This consists of welded aluminum with selected steel and aramid-laminated plates. This armor is in place to protect the single operator. It is intended to protect him against small arms fire, shell shrapnel, or a mine detonation. It is no match for a tank shell or missile though. The operator is located at the rear left of the M9 under an armored cupola with eight vision blocks. When operating head-out, a small windscreen with integrated wiper can be folded up to protect him from dust and debris. In combat conditions, however, the vehicle is operated with all hatches closed. Due to the location of the position, visibility was extremely poor, as the Operator could not see the ground directly in front of him. The M9 also has an optional NBC (Nuclear, Biological, Chemical) protection system. The Operator enters the vehicle through a cut out at the back of the M9 that doubles as a channel for the radiator to vent out through. Once he has climbed into this channel, the operator can turn left and climb in through the cupola’s hatch.

A side-on view of the M9 showing its unique profile. Note the individual armor panels on the side of the hull, protecting the Operator’s position. Photo: Sabot Publications
An M9 at Aberdeen Proving Grounds in the 1980s. Photo: Richard S. Eshleman

Earthmoving

Quite clearly, the most important feature of the ACE is its ability to move earth. This is achieved with the use of an 8.7 cubic yard (6.7 m³) blade at the front of the vehicle. The lower half of this blade, which is also known as an ‘apron’, can fold upwards for road marches and travel and is held in place via sprung latches. The blade allows the M9 to carve out hull-down positions for gun tanks, dig gun emplacements, perform route denial (creating and filling anti-tank ditches), and improving bridge approaches. It could also be used aggressively to push barricades or debris from the path of attacking allies. If needed, ‘ripper’ teeth can be bolted into the lip of the blade.

Someone familiar with the operation of bulldozers may query how such a light vehicle can be an effective earthmoving vehicle. This is where the ballastable aspect of the M9s design comes into play. Behind the apron is a large ‘bowl’, an empty space designed to hold ballast to increase the vehicle’s weight. To fill this ‘bowl’, the dozer blade is lifted via hydraulic rams. The vehicle is then driven forward, gathering material in the void. At the front of the ‘bowl’, there is a small ‘scraper’ blade on the bottom lip, making shoveling easier. The vehicle will then back off and the dozer blade ‘apron’ lowered to cover the opening. With the added ballast, the M9s weight increases by up to 8 tons/tonnes, bringing it to 24.1 tons (24.4 tonnes). The added weight allows the ACE to shift larger and heavier amounts of material without much extra effort.

An M9 ACE in a training environment fills its ballast bowl with ‘apron’ lifted. Photo: Sabot Publications

The added ballast also gives the ACE equal pushing/towing strength to the Caterpillar D7, a commercial bulldozer twice the weight of the M9 (that also served in the US Military), thanks to the increased tractive effort applied by the added weight. To discard the spoil, there is a hydraulic ram propelled blade that pushes the spoil out of the bowl. The blade is guided by two supports with casters attached, these casters run in a channel and keep the blade straight. When empty, the ballast bowl can also be used to carry small loads of cargo. The vehicles head lights are placed directly on top of the ‘apron’.

2 views of the ACE. On the left, A photo looking down into the empty ballast bowl of the M9. The internal blade is clearly visible and pushed all the way forwards behind the ‘apron’. On the right, a view of the dozer blade with the lower-half folded for travel. Photos: Sabot Publications

Mobility

The M9’s power plant and transmission are located at the very back of the vehicle. The engine, an 8-cylinder Cummins V903C diesel, is rated at 295hp and can propel the vehicle to a top speed of 30mph (48 km/h). This top speed allows the vehicle to keep up with tanks and other armored vehicles in convoys, and allows for rapid deployment.

The M9 features a hydropneumatic suspension. There are four road wheels per side, each one connected to a high-pressure hydraulic rotary actuator. Instead of rubber, which can crack or shed chunks, the wheels are surrounded by a high-tensile polyurethane (plastic) tire. The drive sprocket is mounted at the rear, slightly higher than the road wheels. There are no idler wheels. The hydropneumatic suspension is a necessary feature as, because of the ballast bowl, the dozer blade could not be lowered to meet the ground. The suspension has two modes; Sprung and Unsprung. Sprung mode is engaged for travel and allows the vehicle to travel at top speed and traverse rough terrain and minor obstacles as the suspension arms can travel to their maximum degree. Unsprung mode almost flattens the suspension and limits the travel of the suspension arms, thus tipping the vehicle forwards so the blade or mouth of the ballast bowl can meet the ground.

Diagram showing the different suspension modes. Photo: Presidio Press, Sheridan

Secondary Equipment

The M9 is completely unarmed, aside from any personal weapons the operator might carry. For defensive purposes, the ACE is equipped with eight smoke grenade launchers. These are located in two four-tube banks at the center of the M9, just behind the ballast bowl. These can also be used to provide a smokescreen for allies.

At the rear of the M9 is a two-speed winch capable of a 25,000 pound (110 kN) line pull. This can be used to rescue allied vehicles or pull itself out of a ditch (even one of its own making) if necessary. The M9 is also equipped with a towing hitch at the rear, mounted just above the winch. This can be used to tow supply trailers and other equipment. Using the hitch, the M9 has a drawbar pull of 31,000 pounds (14,074 kg) at a speed of 1.5 mph (2.4 km/h).

M9 Operator, Sergeant Chad Post, 9th Engineer Battalion, sat in the passageway at the rear of the M9 after a mission. Note the winch at the very bottom of the vehicle and the tow hitch just above it. Sgt. Post was a rare example of a man who enjoyed operating the M9. His friend, Andrew Patton, said he was “…the best ACE operator I ever met. This dude would have married one and taken it home if they would have let him…” Photo: Specialist Andrew Patton, 9th Engineer Battalion

Thanks to the hitch, the M9 is sometimes used to tow the M58 Mine Clearing Line Charge or ‘MICLIC’. These devices are used to clear large areas of explosive devices or blast a path through obstacles by use of a rocket that tows a line of explosives. The M58 is placed in a large armored crate located on a simple two-wheeled trailer. The line is 350 feet (107 meters) long and contains 5 pounds (2.2 kg) per foot (30 cm) of C-4 explosives. A total of 1,750 pounds (790 kg) per line. The MICLIC is fired forwards over the vehicle, and if it fails to detonate electrically, it can be manually triggered by time-delay fuses along the length of the line. The line is attached to the rocket via a nylon rope and can reach a distance of 100 – 150 yards (91 – 137 meters). To put this into perspective, an American Football pitch is 100 yards long. When detonated, the charge can clear a lane 110 yards (100 meters) long, and 9 yards (8 meters) wide. This device is often towed, but two of them can be mounted directly to the Assault Breacher Vehicle (ABV).

M9 ACE towing the M58 ‘MICLIC’. This ACE also has the optional ‘ripper’ teeth installed on the blade. Photo: Public Domain

A later addition to the M9, made with its operation in hot countries such as Iraq, was a cooling system for the Operator. One of the problems with the ACE was that the operating cab was right next to the engine, meaning the compartment would often get unbearably hot. This is not ideal in a desert climate. The cooling system took the form of a vest known as the Microclimate Cooling System or ‘MCS’, designed by Cobham. The vest is filled with a water-glycol mix and is powered by a control unit. In the case of the M9, this was placed in the entry passageway.

This was a much-needed improvement to the comfort of the operator. However, it didn’t always go right, as this light-hearted account by Specialist Andrew Patton, 9th Engineer Battalion demonstrates:

“I remember watching a friend, a guy called Nate, use it for the first time. We went out on a mission to build up a berm around an Iraqi Police station. The ACE operator worked hard for a few hours and then when his part of the mission was done he parked his ACE, closed the hatch and took a nap with the vest on but the engine off. Half an hour later the dude threw open the hatch, jumped out, threw his body armor to the ground, shed the cooling vest and stood there shivering in the 110-degree heat…apparently without the engine to heat up the compartment he actually managed to get too cold wearing the thing…”

The Microclimate Cooling System by Cobham. Photo: Cobham plc.

Service

Typically, the ACE is distributed with 22 vehicles per Engineer Battalion, equating to seven per company including an ‘Operational Readiness Float’ (all necessary equipment). Almost all of the 448 production vehicles are in service with the US Army. The United States Marine Corps (USMC) has 100 M9s in their arsenal.

Two M9s of the 43rd Combat Engineer Company, 3rd Squadron, 3rd Armoured Cavalry Regiment work together to clear the highways of Mosul. The M9 on the right is using its blade to fill the ballast bowl of the left M9 with debris so it can be taken away. Note the roughly added armor panels over the Operator’s position on both vehicles. Photo: Sabot Publications

A number of faults have plagued the ACE throughout its service life. Multiple mechanical failures, mostly caused by the hydraulics, have given it a highly unreliable reputation. Even with its mobility and weight-gaining features, the M9 has become viewed as useless by many troops that served with them or has simply required the use of one. The general feeling of many was: “We’d rather have the CAT”, referring to the old reliable Caterpillar D7. Even the M728 Combat Engineering Vehicle (CEV) with its attached dozer blade was a preferred choice, at least up until its retirement in the mid-to-late 1990s. The quote below displays that feeling exactly:

“Hated when one showed up to dig my battle position, they were horrible and very unreliable. Hydraulic system always breaking. Loved me the D7 CAT our engineers used. They did use them [the M9] on occasion to transport EPW’s in ‘03, so I guess they did have some use.”

– Joe Daneri, US Army, retired.

The M9 is issued in the following order:
Engineer Companies in a Heavy Divisions: 7
Armored Cavalry Regiments: 6
Engineer Companies, Heavy Separate Brigades: 6
Engineer Combat Company (Mech) Corps: 6
Headquarters and Headquarters Company (HHC),
Engineer Battalions, Light Infantry Divisions: 6
Engineer Companies, Separate Infantry Brigades (Ribbon): 4
Engineer Companies (Assault Float Bridges)(Ribbon) at Corps: 2
Engineer Companies (Medium Girder Bridge): 1
Bridge Companies (Ribbon): 1

The M9 ACE has served in the Gulf War (1990-1991), the Bosnian War (1992-1995), the Kosovo War (1998-99), the War in Iraq (2003-2011) and the War in Afghanistan (ongoing). Unfortunately, the only real records of the M9s operation in a combat zone come from the Gulf War and the War in Iraq. Even then, they are sparse details at best. None the less, what is known is presented in the following sections.

Gulf War (1990-1991)

Operation Desert Storm, the combat phase of the Gulf War, is where the M9 ACE saw the most action, performing well in combat operations. It proved highly effective as Coalition forces assaulted Iraqi units in the besieged Kuwait City. They rolled through roadblocks and smashed through Iraqi fortifications in breaching operations. Despite having a similar pushing/towing strength as the D7 Caterpillar, it was soon found that the M9 was not quite as efficient when it came to earthmoving. However, its flexibility and maneuverability were appreciated by mobile armored units, especially when traversing vast swathes of desert. This somewhat made up for the slightly less effective digging ability. The armor on the M9, though thin, was still far better than the D7, a feature appreciated by the operators.

An ACE of the 5th Marine Regiment, tows a ‘MICLIC’ trailer across the desert in Kuwait. Photo: Lance-Corporal Andrew P. Roufs

ACEs led the way when American Forces breached the border obstacles between Saudi Arabia and Iraq, demolishing trench lines along the way. However, the reliability issues of ACE and its general shortcomings did cause problems and a number of delays. When the M9 suffered a hydraulic fault, it could take many hours, or even days if more than one went down (not a rare occurrence) to repair.

M9 ACE and other vehicles of Headquarters Company, Regimental Combat Team 1, US Marines in the Kuwaiti desert. Photo: Cpl Mace M. Gratz

The War in Iraq (2003 – 2011)

The poor reputation of the M9 was set in concrete by the start of the Iraq War in 2003. A number did serve in the 8-year conflict, much to the chagrin of many an American soldier. By the later stages of the war, its flaws were plainly clear. It became apparent that the ACE had trouble dismantling enemy anti-tank obstacles such as berms or ditches. Due to the location of the operator in relation to the blade, he cannot see the ground he is scraping resulting in the risk, when tackling a ditch, of toppling forwards into the void.

When digging a battle position for a Tank, they were useless in my opinion. I always preferred the CAT dozers, especially when you hit rocky subsurface. Just hope they had their rippers installed. Even the M88 was more useful than an ACE when back blading the spoil. If our mechanics weren’t busy they’d help out in some units.”

– Joe Daneri, US Army, retired.

An M9 ACE is used to scrape a road clear in Iraq. Photo: 20th Engineers

Second to this, the lack of armor in a War full of IEDs (Improvised Explosive Devices) and RPG (Rocket Propelled Grenades) wielding insurgents began to trouble many Operators. One officer described the M9 Operator as: “Alone, Unarmed, and Unafraid”. This flaw was amended somewhat, but in a manner that didn’t make many other units happy. It became standard operation for two M2 Bradley IFVs (Infantry Fighting Vehicles) to protect the M9 as it went about its business. That is two vehicles, intended to support infantry, occupied with the protection of one vehicle, leaving infantry units without armored support. It was deemed necessary for operation success, however, as the M9 could not defend itself as it was completely unarmed.

In early-2007, a couple of famous M9s took part in an operation in Ramadi, a city in central Iraq. The aim of the operation was to install an Observation Post (OP) between Camp Ramadi and a Combat Outpost called ‘Steel’. The M9s in question were ‘Dirt Diggler’ and ‘The Quicker Pickerupper’/’Bounty’, belonging to C. Company 9th Engineer Battalion, 1st Infantry Division.

The M9s in question. ‘Dirt Diggler’ and ‘The Quicker Pickerupper’/’Bounty’ post operation. Photo: Specialist Andrew Patton, 9th Engineer Battalion

Both of these M9s have quite a story regarding their names…

“After having waited quite some time for the order to move out a bored and rebellious M9 ACE operator named Nate* pulled out a can of spray paint and shocked everybody by graffitiing his vehicle with the now famous “Dirt Diggler” name. The second ACE operator followed suit and painted his vehicle to say “The Quicker Picker Upper, Bounty”. Upon seeing the graffiti, our chain of command nearly lost its collective minds, because spray painting a military vehicle isn’t received much better than graffitiing a building. I stood at a distance and watched as everybody in Nate’s chain of command took turns exploding at him with shocked rage at what he had done. He later told me that our First Sergeant had among other things, threatened that if the paint was still there after the mission, Nate would be removing it with a toothbrush. Naturally, as a lower enlisted man, I thought this was all very funny and made a point of taking several pictures to preserve the incident…luckily for the two M9 ACE operators the spray paint rubbed off almost the instant the dozer blade touched the dirt. No one was punished for the graffiti and the rest of the company’s ACE operators took notice of this and it became a bit of a tradition of ours to graffiti the dozer blade prior to each mission…”

– Sample of a written account by Specialist Andrew Patton, 9th Engineer Battalion. Used with permission.

*This is the same Nate involved in the MCS incident

A few M9s also took part in Operation Thunder Reaper, a route clearance operation which took part in December 2007 in Mosul. The objective was to clear the major highways so they once more became usable by civilians. This consisted of scraping the roads clear with the M9s followed combat engineers repaving them where necessary. The Operation resulted in the clearance of around 10 miles (15 kilometers) of highway.

Upgrade Program

In 2014, an upgrade program that had been running for almost eight years ended. It aimed at fixing the multiple problems that made the M9 such a hated vehicle. These feelings are echoed in the quote below from Joe Klocek, the product manager for Engineer Systems at U.S. Marine Corps Systems Command, Quantico.

“There were performance issues and reliability issues that were becoming a major problem, the initial system was fielded before Operation Desert Storm, so we were dealing with some ‘70s technology.”

The ‘1970s technology’ referred to was the intricate, hard-piped hydraulic lines which so often malfunctioned resulting in lengthy periods in repair shops inactive. It also included the lever-based control systems that made precise work difficult. Visibility was another major issue with the M9, as in combat conditions, the Operator had to control the vehicle ‘buttoned up’ (all hatches closed). To quote, Klocek: “Imagine trying to punch through an anti-tank ditch, 12 feet deep and eight feet wide, and not being able to see anything.”

Two upgraded M9s display their capabilities. The vehicle in the foreground has its apron raised as the ballast bowl is filled. Photo: MCSC

The visibility problems were solved by the introduction of a 360-degree camera system (consisting of 10 separate cameras) by Leonardo DRS called the Vision Enhancement System (VES). No longer is the operator blind to what’s happening directly in front of the dozer blade. The system also provides night vision.

The hydraulic levers were replaced with joysticks, allowing for vastly improved and precise control. This was accompanied by a redesign of the highly problematic hydraulic subsystems. A new, more powerful engine was also added, but the specifics of this are currently unknown. This allows it to be more effective in its bulldozing role. Other improvements include an automated track-tensioning system, improved hull construction, automated fire extinguishers, and a redesign of the internal electronics.

The upgrade M9 ACE was unvieled and tested in 2014. Photo: defense media network

Conclusion

It remains to be seen whether the new upgrades to the M9 ACE will repair its tattered reputation, and prove itself useful to the Modern US Military.

There were other upgrade options for the M9, such as a possible remote control version using a ‘Standard Robotic System’ (SRS) by Omnitech Robotics of Colorado (as used on the M1 Panther II) but, for unknown reasons, this was not accepted. New vehicles that fulfill similar roles as the M9, such as the M105 DEUCE (DEployable Universal Combat Earthmover), also started to appear in the early 2000s, putting pressure on the M9 ACE to perform.
For now at least, the upgrades the M9 has received keep in service with the US Military for the foreseeable future. The vehicle is also currently in service with the Taiwanese and South Korean Military.

An M9 ACE on display at the Army Proving Ground’s (APG) 100-year anniversary show in May of 2017. Photo: Richard S. Eshleman

Turkish Twin

In 2009, a deal was signed with the Turkish company FNSS Savunma Sistemleri A.Ş, (a company partly owned by BAE Systems, owners of the M9 ACE patent) for the production of a local variant of the M9 ACE. The vehicle’s official designation is ‘Amphibious Armored Combat Earthmover’ or ‘AACE’. Although, it is also known as the Kunduz, and as the ‘AZMİM’ or ‘Amfibik Zırhlı Muharebe İstihkam İş Makinesi’.

The Turkish ‘Amphibious Armored Combat Earthmover’ or ‘AACE’. Photo: FNSS

The AACE is far from a straight copy of the M9, and incorporates a couple of very different features. For one, the AACE retained and elaborated on the M9’s amphibious abilities, which largely went unused and was not maintained. To propel it through the water, the AACE features two water jets, placed over the drive wheels. These jets give the dozer a top water speed of 5.3 mph (8.6 km/h), and allow it to swim against currents of 4.9 feet/sec (1.5 m/sec) in rivers or streams. It is also extremely maneuverable in the water, and able to turn 360 Degrees on the spot. Secondly, whereas the M9 is a one-man vehicle, the AACE is operated by two crew. The operating position remains at the left rear of the vehicle, but there are now two seats, one in front of the other. To accommodate this, the cupola of the M9 was exchanged for a simple two-piece hatch.

The amphibious nature of the AACE is crucial to its main task of preparing river banks during river crossing missions. It is of course also used to perform standard bulldozing tasks and operates like one in the same manner as the M9.

The AACE displays its fully amphibious capabilities. Photo: FNSS

After four years of development, the AACE entered service in 2013. The vehicle is currently in the arsenal of the Turkish Army and has become a very popular vehicle, unlike its M9 cousin.



The Armored Combat Earthmover M9 (ACE).


M9 ACE with suspension raised.

Both illustrations were produced by Ardhya Anargha, funded by our Patreon campaign.

Specifications

Dimensions (L-w-H) 20′ 6” (6.25 m) x 10′ 5” (3.2 m) x 9′ 6” (2.9 m)
Total weight, battle ready 16 tons (no ballast), 24 tons (full ballast)
Crew 1 (Operator)
Propulsion Cummins V903C, 8-cylinder, diesel
Maximum speed 30 mph (48 km/h) on road
Suspensions Hydropneumatic
Production 448

Sources

Discussion with Andrew Patton, former Specialist, 9th Engineer Battalion, Iraq War veteran. A written account of some of his experiences with the M9 can be found HERE.
Presidio Press, Sheridan: A History of the American Light Tank, Volume 2, R.P. Hunnicutt
Sabot Publications, M9 ACE: Armored Combat Earthmover, Chris Mrosko & Brett Avants
Armoured Vehicle Database
www.military-today.com
Military Analysis Network (Future Upgrade details)
www.defensemedianetwork.com
www.defencetalk.com

M9 ACE Armored Combat Earthmover In Detail
M9 ACE Armored Combat Earthmover In Detail

By Sabot Publications

The M9 ACE in Detail is a 132 page full color photo journal of the U.S. Army’s armored combat earthmover. The book contains extensive color photos of the ACE in action in the field, and a comprehensive walkaround section for the detail-oriented. Makes a great companion to the Takom 1/35 ACE model kit!

Buy this book on the Sabot website!