M88 – the Mighty HERCULES
The M88 armored recovery vehicle was America’s solution to finally create a purpose-built armored tow truck that could move the heaviest vehicles the military had to offer.
With the Cold War arms race in full swing, American military planners wanted bigger and better main battle tanks to counter Soviet technological developments. The only problem was they had no way of recovering these beasts if they got stuck, broke down, or were damaged.
The M88 solved their problem since it could accommodate the increasingly heavier main battle tanks the US was developing that existing recovery vehicles simply could not handle.
Its simplistic design, multiple recovery methods, and powerful engine have made it the vehicle of choice for the US and over a dozen foreign militaries for the past several decades, earning it the distinction of being the longest-serving armored recovery vehicle in history.
- Read More: The M-51 “Super Sherman”
Just how the M88 has been able to stand the test of time from Vietnam to the present day is a testament to its versatility, utility, and easy upgradeability to meet changing armor needs.
The US emerged from the Second World War at the top of its armor game, or so it thought. The Soviet Union quickly developed larger, heavier main battle tanks like the T-54. The US knew it needed to catch up with them or risk being outgunned. American designers created the M47 Patton tank as its counterpart on the battlefield, but there was a problem. The Army had a several-year period where they had no reliable recovery method using just one vehicle to bring back a Patton.
American engineers designed the M74 Armored Recovery Vehicle as a stop-gap measure to try and fix this. Built off the chassis of repurposed M4 Sherman tanks, the vehicle served well when handling the lighter tanks fielded during World War Two and its immediate aftermath.
However, the M74 weighed just 42 tons while the Patton came in at 50 tons.
Because of the weight disparity, the M74 could not safely pull out a Patton by itself. The Army, already scrambling for an immediate replacement, met with the industry to present their problem. Bowen McLaughlin, based out of York, Pennsylvania, stepped forward with a solution.
Although weak, Bowen McLaughlin did not want to reinvent the wheel since the M74 provided some crucial design features. Its A-type boom, horizontal winch, and front spade were all components that the company incorporated into its design drawings that the Army ultimately accepted.
At 27 feet long, 11 feet wide, and 10 feet high, the experimental T88 as it was then known was only slightly larger than its M74 predecessor. However, the Army required the company to design a completely new hull since the plan for converting existing M48 hulls was scrapped due to it being the main battle tank in service. No M48 Pattons could be spared lest America got into a war with the USSR in the meantime.
Once Bowen McLaughlin had designed the new hull for what would become the M88, the next components to be made were the recovery machinery. The company kept the same style of A-type boom, and once in position, it could reach out another four to eight feet fully extended. Its max rated load was at 22.5 tons, with the spade out going down to about five tons with the spade up.
- Read More: Why do Tanks use Angled Armor?
The spade acts just like a stabilizer on a crane. When the operator pushes the spade down, it helps the M88 support the load extended out in front of the vehicle, preventing the front end from dipping down too far.
The winch was the mainstay of the operation. At 200 feet long and a rated load of 45 tons, the winch was explicitly built to pull the M48 Patton to safety.
With the rest of the vehicle built, the only major piece of equipment left to figure out was the engine. The M74 had a pretty weak 450 hp V-8 gasoline engine. Bowen McLaughlin knew the bread and butter of the new vehicle would be the engine, so it was this aspect that the company dedicated most of its time to designing.
Despite their best efforts, the initial testing with the Continental AVI-1790-8 proved to be lackluster at best. As luck would have it, during this time, a new Army initiative at saving fuel helped create a more powerful and fuel-efficient engine, the Continental AVSI-1790-6A. This same engine at the time was being retrofitted in the M48A3 models of the Patton tank.
The main difference between this new 12-cylinder engine and the previous version was that it was supercharged. This meant that an air compressor was attached to the engine, forcing pressurized air into the combustion chamber. The result gave the M88 a massive 980 hp and 1,940 ft-lb (2,630 Nm) of torque, just what a tanker would need if stuck in the mud or a snowbank somewhere.
With this problem figured out, the Army approved Bowen McLaughlin for total production starting in 1960, and within the next four years, over 1,000 vehicles rolled off the factory floor.
The M88s produced performed beautifully for the next ten years until the newest iterations of the Patton tank came out, the M60. Though the M60 first debuted in 1959, by the end of the Vietnam war, the new armor upgrades to the tank started to increase its weight beyond the safety limit of the M88.
Because of this, the military needed to upgrade the M88. It was fitted with a new engine, this a time a diesel, with less power but better fuel economy. This was the Continental AVDS-1790-2DR, a supercharged diesel V12 that produced 750 hp and 1,720 ft lbs (2,332 Nm) of torque.
A new transmission also had to be installed to accommodate the new engine. But the new auxiliary power unit modification was probably the best change to the system.
The Auxiliary Power Unit, or APU, allowed the M88 to operate its winch, boom, and spade even if the main generator in the vehicle lost power. This requirement came from its extensive Vietnam service, where recovery operations under fire necessitated an emergency way of retrieving vehicles despite battle damage.
Both the M88 and M88A1 were heavy machines, weighing in at 55 tons.
- Read More: What Does a Muzzle Brake Do?
Even though the military knew they needed the M88A1, they debated for several years with Congress on funding the new project. The original idea was to repurpose about half of the existing M88 fleet with these new configurations.
Still, Congress wanted the military to find a foreign backer to help offset the cost. Ironically enough, in 1975, four years before the Iranian revolution, the Shah of Iran wanted in on the project.
Flush with cash for the program, M88A1s began rolling off the production line in 1977, with completely new vehicles going to Iran and the American military receiving half new, and half repurposed ones.
The M88A2 HERCULES
For the next decade, the M88A1 proved superb not just with the American Army and Marine Corps but with other militaries, including Israel, Iran, Taiwan, West Germany, and numerous others. However, the next generation of American Main Battle Tanks would force the military to return to the drawing board for the third and final iteration of the M88.
The advent of the M1A1 Abrams tank was an eye-opener to the rest of the world. One of the most capable MBTs in the world, then and now, this 68-ton monster was too much for just one M88A1 to handle safely.
Because at least two M88A1s were now required to rescue an Abrams tank, the military needed another version of the M88. This time around, though, there would be some very serious changes. The end result was the M88A2 Heavy Equipment Recovery Combat Utility Lift & Evacuation System (HERCULES).
The first and most obvious difference when looking at the new vehicle was the armor. On the M88 and M88A1, the armor protection was a simple 20 mm to 25 mm plate around the vehicle’s hull. With the M88A2, 30mm thick plates were placed around the upper half of the tracks in addition to the existing armor.
The military also changed the boom design. Using physics and geometry, redesigning the boom to be a squared-off type vice a rounded type helped increase the lift capacity of the boom to a staggering 35 tons.
The next most significant change was to the interior of the vehicle. Before, a crew of four consisting of a driver, rigger, mechanic, and tank commander was required to man the M88. Now, the rigger’s seat was taken out and the rest of the crew cross-trained in rigging.
With all this extra space, the crew could perform advanced maintenance in the field, like replacing the APU or mechanical clutch, which would have been impossible before.
But the HERCULES did not just get more powerful on its own since it draws its power from its incredibly beefed-up hydraulic system. While the previous models had just one hydraulic pump for the vehicle, the HERCULES has three.
These are necessary because the cable on the winch for the HERCULES is about three times the weight as before. To assist in paying it out, engineers added an auxiliary winch. For the boom to be stronger, it, too, got a dedicated hydraulic pump. Overall, the hydraulic system is what makes the HERCULES as strong as it is and gives it the power to move any armored vehicle on the planet. Its winch can pull 70 tons.
The M88A2 now weighed 70 tons, and required some serious muscle in the engine department.
This time around the military weren’t playing any games, choosing the AVDS-1790-8CR V12 diesel engine. This air cooled engine is turbosupercharged, pushing its power to a staggering 1,050 hp. Most importantly, the engine also got a new addition of its own internal hydraulic oil coolers to cool the massive hydraulic system not seen in previous models.
The M88A2 has a top speed of just under 30 mph.
The M88, in its various iterations, has served continuously in the US military since 1961. All of the variations were financially successful export models that have equipped armies on every continent.
In US service, the M88 has proven itself in combat from the jungles of Vietnam to the mountains of Kosovo to the deserts of Iraq, Kuwait, and Afghanistan.
With over 3,000 units of all models produced, and almost 1,200 still operating in the US Army, the M88 has cemented itself as the most combat-tested and reliable armored recovery vehicle of all time.
If you like this article, then please follow us on Facebook and Instagram.
Though the Army has plans to continue upgrading it, it is doubtful that it will ever go away in the foreseeable future.