Warplanes: South Korea’s Troubled KF-21 Jet Fighter Project


April 11, 2024: The South Korean KF-21 project began in 2010. South Korea sought nations willing to cooperate in developing the new fighter by providing some of the money needed to complete the program and then purchase some of the fighters. Indonesia agreed to such a deal but proved to be an unreliable partner. Indonesia did not provide the promised funding and then Indonesian engineers involved with the project were caught trying to steal the jet fighter technology South Korea had already developed. The Indonesian government insists it knew nothing about the attempted technology theft and that it will catch up on missed payments it promised in order to become a 20 percent partner in KF-21 development. Indonesia is late in delivering over a billion dollars. The Indonesian partnership included KF-21s eventually being built in Indonesia. In 2024 Indonesia revealed that it had rejoined the KF-21 program and was prepared to invest in development of the KF-21. When that happens the KF-21 cooperation deal with Indonesia will be revived.

Poland offered to be a development and production partner. Poland can afford this and has its own industrial base that is capable of co-producing KF-21s. Poland plans to join the program in 2026, after development of the Block 1 model of the KF-21 is complete and work begins on the Block 2 model. The Block 1 model is capable of air defense while Block 2 is capable of carrying and delivering surface attack weapons.

KF-21 development began in 2011 and the first KF-21 test flight was in 2022. South Korea expects the KF-21 to be ready for use and mass production by 2026. The plan was that by 2028 South Korea would have 40 KF-21s in service with 80 more arriving over the next four years. Additional KF-21s would be built for export customers. Development costs of the KF-21 were over $8 billion and each aircraft costs $65 million to build. That is a competitive price for a modern jet fighter.

This all began in 2001 when South Korea announced the KF-X advanced multirole jet fighter project. South Korea wanted to develop and manufacture a modern jet fighter to replace its 167 F-16s, 19 F-4s that are being retired by the end of 2024, and 80 F-5s. The 59 F-15K fighter-bombers will remain in service until about 2030. In addition to KF-21s, South Korea already has 39 F-35s, with 20 more on order. The F-16s will be gradually replaced by F-35s and KF-21s.

The preliminary KF-21 design was completed in 2018 and approved in 2019. In 2022 six KF-21 prototypes made their first flights in 2023. These six prototypes continue to be used for flight tests and performance verification. The prototypes are not identical and are modified to keep up with what the final KF-21 aircraft will be. South Korea is spending about $50 million to develop the KF-21, which is a 25 ton, twin-engine, single seat fighter bomber. The engines are American F414 models built in South Korea under license. Up to 7.7 tons of weapons can be carried for surface attack missions. There is an internal 20mm autocannon with 480 rounds of ammunition. Max combat range is 1,000 kilometers while ferry range, carrying only additional fuel pods, is 2,900 kilometers.




Help Keep Us From Drying Up

We need your help! Our subscription base has slowly been dwindling.

Each month we count on your contributions. You can support us in the following ways:

  1. Make sure you spread the word about us. Two ways to do that are to like us on Facebook and follow us on Twitter.
  2. Subscribe to our daily newsletter. We’ll send the news to your email box, and you don’t have to come to the site unless you want to read columns or see photos.
  3. You can contribute to the health of StrategyPage.
Subscribe   Contribute   Close