K9 Thunder by ThePikzel on DeviantArt (original) (raw)

South Korea won the poll, so Kim's Kingdom has to wait for another day to shine.

K9 Thunder - 155mm self-propelled howitzer from South Korea. This is a long story so lets begin.

Story starts in the 1980s, the Republic of Korea Armed Forces started to need a new artillery system to counter the ones used by North Korea. North Korea in 70s and 80s had upgraded their fleet of self-propelled howitzer with their domestic designs including Tŏkch'ŏn or M-1978 Koksan.

Meanwhile South Korea operated American-made 175mm M107 and 155mm M109 (M109A2 was produced in Korea as K55). Those weren't bad, but had shorter firing ranges than the mentioned Koksan howitzer. They were also outnumbered.

Ministry of Defence, seeing the success in designing and producing towed howitzers like 105mm KH178 and 155mm KH179 as well as prodcuing self-propelled K55, ordered the development of a new system that would have a longer firing range, faster firing range and high mobility. Development started in 1989 led by the Agency for Defense Development (ADD) and Samsung Aerospace Industries (Nowdays Hanwha Defense).

Previously ADD had built an automatic loading system by collecting and analyzing data from artillery. They saw that burst fire and quick relocation would become the dominant factor in artillery battles in the future.

1987, ADD offered an upgrade plan for existing K55, inspired by US M109 Howitzer Improvement Program (HIP), but that offer was rejected by Republic of Korea Army in 1988.

This resulted in beginning of K9 development and ADD was determined to create a new weapon system. Conceptual model was worked on until 1991.

Early concepts requested by military had pretty weird features for vehicle of this kind. This included capability to cross rivers and, even more strange, M61 Vulcan 20mm Gatling gun was an anti-air weapon. This was thankfully removed as it was unnecessary.

September of 1990, a Korean developer visited the United Kingdom in search of turret design technologi developed by British Vickers for AS-90. Vickers refused the technology transfer, instead offering AS-90 for sale.

Developer also visited Marconi, but the negotiations ended with an unsatisfactory result due to high requested price. This led to developer pursuing a domestic electrohydraulic driving system, using the experience in turret design and turret dribing devices of the K1 Main Battle Tank. Simulator was built in 1991.

Next year, 1992, researchers found that the disproportionate moment of the 52-caliber was twice as of the K55. Balancing machine did not sufficiently compensate for the imbalance moment value due to the change in the position of the armament. The driving force was very diffrent depending on driving angle. This is the same problem which appeared in German Panzerhaubitze 2000 which was under development at the time.

A joint research team from the ADD and Seoul National University of Science and Technology calculated an accurate theoretical model and calculated an accurate theoretical model and concluded that adjustment to system configuration was possible without major design changes.

Another problem encountered was a loud noise from hydraulic generators, which could cause hearing loss under long exposure. Engineers of the ADD and Dongmyeong Heavy Industries (now Mottrol) found that the noise was due to excessive shaking of hydraulic pressure, this part in source explains some physics, so just know they made a device that made it quieter.

Winter of 1991, ADD held talks with engineers from Samsung Aerospace Industries special reserach institute. ADD originally demanded that Samsung be in charge of system assembly only, as the company had no experience in developing its own tracked vehicle desgin, despite having experience in manufacturing K55 under license. The decision was overturned and the manufacture of the Mobility Test Rig (MTR) was decided upon.

Samsung worked with KAIST on suspension and Seoul National University & Pohang University of Science and Technology on mobility systems. The engine was co-developed with American AAI Corporation. The test of the MTR was finished by November in 1992.

From 1992 to 1993, the developers explored and confirmed the required operational capability such as the system suitability of major components and the possibility of reaching the maximum firing range of 40km. An internal review predicted that the howitzer would achieve a localization rate of 45.5% technologies by the late 1990s. Unsatisfied with this review, South Korea decided to continue developing main system, main gun, 155mm ammunition, fire control system, structure and autoloader, meanwhile the engine, transmission and integral navigation system were to be imported and license produced.

Main issue was with designing the main gun and suspension due to lack of experience.\

Between March and August of 1993 the development was delayed as result of purge of Hanahoe, a private military club within Korean Armed Forces, who aligned with military dictator Chun Doo-hwan, by president Kim Young-sam who was elected by democratic election.

Not only that, but the Army Logistics departent also refused to sign the letter of agreement for XK9 until a development plan for the maintenance elements is created.

September of 1993, Defence Ministry approved a prototype development plan after Joint Chiefs of Staff finalized the system development agreement in August of that year.

Since domestically developed armor steel plates were applied for the first time, the researchers decided to produce and compare armor plates from both imported and domestric materials to reduce the risk. At the same time, Samsung begam to train and employ master craftsman welders whose skills were verified by the U.S. Aberdeen Test Center. Armor plates went through a series of tests such as stress and ballistic impacts, and reseachers verified the domestic plate performed better.

ADD saw that the Hydropneumatic Syspension Unit provides better mobility and crew comfort. At the time HSU caused problems with some equipment and it was yet to be fully verified for durability, which ingited international controversy. Therefore it was inevitable to introduce and localize a British Air-Log (now Horstman) HSU that is used for the AS-90. However when the researchers applied the Air-Log HSU on the MTR and prototypes, they soon fount that the HSU couldn't support heavier vehicles, thus failing the durability test. Since May of 1997, engineers from the ADD and Dongmyeong Heavy Industries have spent a year on 5 redesigns and 11 durability tests. After the new HSU was made, it was exported back to UK.

Spring of 1992, the test gun experienced a detonator breakage caused by a diffrential pressure, at which the pressure increases in the opposite direction of the shell. After many years of failures and updates, reseachers decided to change the shape of the propellant in 1997. The tiny pellets of the US-style propellant, which have 7 holes simmilar to briquettes, were replaced with 19 holes by mimicking the German style without knowing the specification. After many tests, the gun achived a range of 40km in 1998.

Total of 3 prototypes were built and performed their first open trials in 1996. During the test, the prototypes succeeded in firing at distances of 40km and 6 rounds/minute, but failed to fire 3 rounds in 15 seconds.

December of 1997, one of the prototypes was damaged by fire, due to failing complete combustion, after testing 18 rounds in 3 minutes. One researcher was killed and 2 injured. Thankfully, the damaged prototype's internal system survived and was repaired for further use.

After firing 12 000 rounds and driving 18 000km over 10 years of development, it was finnaly finished. October of 1998 with the achievement of an 87% localization rate.

Contract for firt batch of K9 vehicles was awarded to Samsung Aerospace Industries in December 1998. The produced vehicles were supposed to be delivered to Republic of Korea Army, however, a 1999 naval battle between the two Koreas caused the delivery to be rerouted to the Republic of Korea Marine Corps.

The first vehicle was rolled out in December 1999 and was given to the marines in Yeonpyeongdo.

K9, aside Korea, is also used/ ordered by Poland, Turkey, Estonia, Finland, Australia, Egypt, India and Norway. Its also evaluated by Romania and Vietnam.

K9's chassis is used for Polish AHS Krab howitzer. It was chosen as replacement after the orignal chassis was found to be defective.

K9 variants include:

>K9PL - Version to be produced for use in Poland with Polish subsystems.

>T-155 Fırtına - Turkish version of K9 produced since 2001.

>K10 Ammunition Resupply Vehicle

>K11 Fire Direction Control Vehicle

Name: K9 Thunder

Type: Self-Propelled Howitzer

Country of Origin: Republic of Korea (South Korea)

Year: 1999