K1 tank
The K1, sometimes referred to as the 88 Tank , is a South Korean main battle tank designed by Chrysler Defense and Hyundai Precision Industry for the Republic of Korea Armed Forces. It is a derivative of Chrysler's M1 Abrams, tailored to meet unique ROK requirements. The K1A1 is an upgraded variant based on the GDLS technical data package with a 120 mm 44 caliber smoothbore gun, and is outfitted with more modern electronics, ballistic computers, fire control systems, and armor. Hyundai Rotem produced 1,511 K1 and K1A1 tanks between 1986 and 2011.
Development
In the early 1970s, South Korea received an intelligence report about North Korea locally producing Soviet T-62 tanks. Meanwhile, the U.S. 7th Infantry Division began withdrawing from South Korea from 1969 to 1971 under the Nixon Doctrine. South Korean President Park Chung Hee requested the latest variant of M60 tanks to maintain the balance of power. However, the United States responded by transferring used M48 tanks and providing upgrades instead; South Korea received 25 M48A5s from the United States Forces Korea and numerous M48A3s that were used, but in good condition, during the Vietnam War.Under the agreement, South Korea received the technical data package of the M48 Patton and its upgrade kits for 12 major enhancements. South Korean engineers were sent to the United States Army Depot in Alabama for training, such as armor cast steel welding and production, precision manufacturing, assembling skills, quality inspection, and test evaluation. Around the same time, Park Chung Hee ordered the development of a domestic tank and personally summoned Chung Ju-yung, the founder of Hyundai Group, to recommend building a tank factory. Chung Ju-yung, thinking that the president asked for a train factory, promised to build one. The chairman was shocked after learning about his misunderstanding from the president's secretary as he was leaving the building.
Not satisfied with the M48 Patton upgrade, South Korea began looking for a new tank that could overwhelm every North Korean counterpart, as the existence of the T-62 and its manufacturing facility were confirmed by satellite images in 1976. South Korea first asked Chrysler Defense for a solution to acquire a better tank, and Chrysler suggested purchasing the M60A3 or producing it in South Korea. Because the American offer was an outdated design, South Korea then contacted KraussMaffei of West Germany to receive technical assistance, and KraussMaffei offered a unique tank design based on the Leopard 1. Both South Korea and West Germany kept the cooperation secret because the two nations believed that the United States would intervene once the information had been leaked. In 1977, as expected, Chrysler Defense showed interest in the South Korean tank project after its engineers became available and wanted to generate more profit after the development of the M1 Abrams. This time, Chrysler offered a new tank based on the newest M1 Abrams. Eventually, the American design was chosen, and a memorandum of understanding was signed on 6 July 1978 to supply two prototypes, and the executive contract was signed on 1 December 1978.
Between 1979 and 1980, several MOUs were signed between the two nations, mostly regarding intellectual rights and royalty payments. According to the MOUs, the United States would provide and install its state-of-art Special Armor Package, in which the material and protection were identical to the M1 Abrams, while restricting South Koreans during its installation due to national security reasons. Exporting of the K1 is strictly controlled and needs authorization from the United States as many sensitive systems are installed, and South Korea was required to pay a royalty to Chrysler Defense. Also, 44 designated parts cannot be changed without United States approval, and some parts must be purchased periodically. In addition, South Korea would have the rights on, and be limited to, the technologies developed uniquely with the money provided by South Korea, while Chrysler also claimed the rights to use them in the future. On the other hand, South Korea benefited from the development cost of the cooperation with Chrysler; South Korea paid $60 million for the prototype development, far below the $700 million spent on the M1 Abrams. However, the biggest disadvantage in the agreement for South Korea was that Hyundai Precision Industry, which had planned to produce the tank at its new factory, was excluded from direct involvement in designing the tank. Since Koreans had not made tanks before, they would be unable to produce tanks as they did not understand the structure and technology of the tank even with prototypes in hand.
From October 1980 to April 1981, Chrysler had three meetings with Hyundai to confirm the required operational capability and presented a small-scale mock-up and reports. During the production of the prototypes, Chrysler Defense was sold to General Dynamics Land Systems in March 1982. Two ROKIT prototypes were delivered with designations PV-1 and PV-2 in 1983 and were tested at Aberdeen Proving Ground based on U.S. military standards. During the trial, the PV-1 failed to climb the longitudinal slope of 60%, experienced a fire on the 1,200 hp Teledyne Continental Motors AVCR-1790 engine. PV-2 also reported issues with its fire control system: winter frost causing LOS to shake, system takes too much time to warm up, electromagnetic waves interferences, and lock up of the ballistic computer. Protection tests were done on separately built ballistic hulls and turrets, which showed some flaws during the test. Eventually, many known problems were fixed. In the end, GDLS transferred the PV-1 along with 1,370 pages of blueprints and the TDP, but the number of blueprints was insufficient to produce the tank.
| Model | GDLS XK1 | GDLS XK1 |
| Commander | — | 12.7 mm or 7.62 mm machine gun mount Added LED display and monocentric eyepiece |
| Gunner | Newer design power control handle | Integrated azimuth data to ballistic computer Relocation of systems Conventional power control handle |
| Loader | Turret ring: 78 inches | Turret ring: 85 inches Increased head clearance |
| Driver | Regular telescope M1-style chassis frontal angle Gear shift integrated in T-bar | All-position telescope Lowered frontal angle for better view Gear shift separated and moved to driver's right side Remodeled panel configuration |
| Side skirts | RHA | RHA + SAP |
| Suspension | HSU: 1, 5, 6 Torsion bar: 2, 3, 4 | HSU: 1, 2, 6 Torsion bar: 3, 4, 5 |
| Gun depression | -6 degrees | -10 degrees |
| Engine bay | — | Power pack air filters restructured |
During the development phase, a team of Korean engineers from Hyundai Precision Industry was dispatched to join Chrysler's developer team to look over the progress. Although the contract limits the technological access of Koreans, engineers from both nations freely shared information during friendship interactions, including a classified specification of the M1 Abrams. When the upper management of Chrysler found out about this, they built a wall in the office to prevent information leakage. However, Koreans managed to obtain significant data during their three-year presence. In addition, the manufacturing team of Hyundai came for a tour of the American tank factory to understand how to build a tank factory. Despite being denied for detailed inspection, Koreans memorized required machine tools and facility size by counting footsteps, which helped to build a new factory at Changwon.
In 1983, Hyundai accepted GDLS' new offer and acquired special welding of armor plates, assembly of major devices, and weapon testing technologies. Thirty engineers from GDLS were also sent to South Korea and participated in producing and testing preproduction models. From September 1984 to August 1985, a total of five practical prototypes were completed, and went for further testing in South Korea. However, Hyundai realized that GDLS had made a crucial mistake by providing outdated blueprints that did not reflect the latest fixes, and XK1s began to experience the same issues they saw from early prototypes. In addition, the lack of detailed blueprints forced Korean engineers to rework the tank and create five thousand design changes and ten thousand pages of blueprints. The biggest change during this process was the switching of the mobility system from American to German, in which the design change was done by GDLS. The air-cooled AVCR-1790 had lower torque, was thus unable to drive at high incline angles, and experienced fire several times, contributing to unexpected fire tests that challenged the tank's survivability. For this reason, the MTU Friedrichshafen MB871Ka-501 water-cooled engine and the ZF Friedrichshafen LSG 3000 transmission were chosen for the new power pack. These preproduction variants entered service with the South Korean military in February 1986.
Meanwhile, Hughes' GPSS continuously suffered with issues such as low accuracy and operational uses. Also, South Korea gave up localizing the GPSS as Hughes doubled the price for the license. Later, GDLS, which acquired Hughes in 1985, revealed that the system uses parts from Canada, West Germany, and Switzerland, and thus requires time-consuming multinational cooperation to solve problems. In 1986, another contract was signed between Hyundai and GDLS for updating the GPSS, increasing the cost of the gunner's sight. This unsatisfactory situation led South Koreans to look for alternative options immediately. In April 1987, the K1 tank test evaluation for conditional mass production was completed, and serial production began in September 1987. On 18 September, the tank was given the nickname 88-Tank by South Korean president Chun Doo-hwan to celebrate the upcoming 1988 Summer Olympics.
A total of 1,027 K1s were produced between 1986 and 1997 in three batches with design changes in each batch. In 1995, the K1s received their first depot maintenance at Hyundai Precision Industry in the order of production. The work includes the application of third batch updates on the earlier produced vehicles.