[Militech] Localization of the K9 Self-Propelled Howitzer's Engine... Laying the Foundation for Korea's Defense Industry [Yang Nakkyu's Defence Club]

On-site Report from the STX Engine Changwon Plant

Export Success Story Driven by Localization over German Engines

The surge in global security demand triggered by the conflict between the United States, Israel, and Iran presents a significant opportunity for Korea's defense industry. The United Arab Emirates (UAE) defended itself against Iranian missile attacks using the KM-SAM Block II (Cheongung-II) medium-range surface-to-air guided missile, reportedly achieving an interception success rate of over 90%. This has proven the real-world performance of Korean defense systems. The resulting trust in other weapon systems such as the K9 self-propelled howitzer, K2 main battle tank, and Chunmoo multiple launch rocket system is making the government's goal of becoming one of the world's top four defense powerhouses increasingly tangible. Localization efforts are also accelerating. At the STX Engine Changwon plant, which succeeded in localizing the engine for the K9 self-propelled howitzer—Korea's largest defense export product—operations were in full swing.

More than 500 processed parts placed by type on the production line must be assembled to create a single engine. Photo by STX Engine

Upon entering the Changwon plant, the “World Best” logo immediately caught the eye at the main entrance. A company official said, “With government support in 2021, we succeeded in developing the localized K9 self-propelled howitzer engine, and over the three-year development period, we localized more than 500 parts,” adding, “We will demonstrate the power of Korea’s defense industry.” The diesel engine powering the heart of the K9 self-propelled howitzer was originally manufactured in Germany. In accordance with the 1999 plan to modernize self-propelled artillery, STX Engine began producing MTU engines under a technology transfer agreement with Germany.

German Engine Maker Restricts Exports Every Time K9 Self-Propelled Howitzer Is Sold

Production itself was not a problem, but exports were always challenging. The K9 self-propelled howitzer has been exported to over 700 units in countries such as Turkey, India, Norway, and Poland. Every time the K9 was exported, approval from the German government was required. Germany restricted export approvals in response to changes in international affairs in the Middle East, including the UAE. As a result, Korea’s defense industry secured export orders, but deals repeatedly failed to materialize into contracts. This created a pressing need for a domestically produced engine. STX Engine took on the challenge, achieving results in a field that had previously been almost barren for Korea’s defense sector. Thanks to the technical partnership with Germany’s MTU, as much as 80% of the K9 self-propelled howitzer’s engine parts could be produced domestically, laying the groundwork for successful localization.

The K-9 domestically produced engine undergoes more than 20 tests, including engine revolutions per minute (rpm), coolant temperature, and voltage. Photo by STX Engine

To see the localized K9 self-propelled howitzer engine, I entered the production line. The metalworking machines were operating nonstop. Processed parts were placed on the line by type, but at a glance, they just looked like lumps of metal. Over 500 small parts must be assembled to create a single engine. Even the hundreds of tools on display made it clear that the assembly process is no easy task. The key to each part is precision. If machining is not exact, the engine could stop functioning.

The measurement room was filled with various instruments for checking specifications. On one side, the size of the engine’s core component—the cylinder—was being measured and compared to engineering drawings. The margin of error was just 20 microns (0.002 mm). A company official explained, “It takes 40 minutes to measure a single part,” indicating just how meticulous the process is.

Assembling Over 500 Precision-Processed Parts to Produce an Engine

The left side of the assembly hall was for marine engines, while the right side was for land engine assembly. Along the walls, various parts were organized like a logistics center. On the marine line, main engines (the 1163 series) for 500-ton Korea Coast Guard patrol vessels were being assembled. With 5,700 horsepower, these engines appeared about five times larger than their land-based counterparts. On the land engine assembly line, tank engines and self-propelled howitzer engines were being assembled. About ten employees were assembling each engine from more than 500 parts, and the outline of the engine became clearer as it moved down the line. At the end of the line, nine completed engines were displayed—these are K9 self-propelled howitzer engines destined for export to countries including Egypt and Poland. There are two types: those produced under a technical partnership with Germany’s MTU, and fully localized engines.

A company official explained, “For engines produced with MTU technology, about 30 core parts must be imported from Germany. In contrast, the localized engine uses only Korean-made parts.” The economic effects of localizing the K9 self-propelled howitzer engine are substantial. Considering domestic supply, upcoming orders, and the ability to bypass export restrictions, the industry estimates the value at over 6 trillion won. In addition to increased engine supply for expanded export markets, localization also reduces license fees paid to MTU.

Over 20 Tests for Marine and Land Engines in One Place

Once assembly is completed, the engines immediately undergo test runs. Of the seven test cells, three are for marine engines and four are for land engines. Inside the test cell, a virtual transmission was attached to the engine—appearing almost like a cube plugged into an artificial heart—for testing. Multiple pipes are connected to each engine, and fuel and engine oil are injected for operation. The domestically produced K-9 engine undergoes over 20 tests, including engine rpm, coolant temperature, and voltage. All these tests must be passed over a six-hour period for the engine to be approved for delivery.

A company official stated, “We have built infrastructure to manufacture and produce core components in partnership with domestic suppliers using purely Korean technology,” adding, “We plan to proceed with follow-up military support based on our localization rate.”

This content was produced with the assistance of AI translation services.