A flight display of the KAI KF-21 Boramae, the South Korean alternative to the F-35

The Republic of Korea, also known as South Korea, is a country in one of the most difficult strategic positions in the world.

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South Korea shows the runway tests of its alternative to the F-35: KAI KF-21 Boramae

In 1950, that country was invaded by its northern neighbor, the communist dictatorship officially and cynically called the Democratic People's Republic of Korea. The war ended with an armistice in 1953, but since then there has been enormous tension between the two countries. It also happens that North Korea is supported by communist China and Russia, while South Korea is supported by the United States, so a new war on the Korean Peninsula would involve the major superpowers.

The Republic of Korea Air Force (ROKAF) operates the F-35. In total, it has purchased 60 of these fifth-generation fighters. However, for years, the South Korean government has been concerned about being drawn into another war and not receiving the necessary aid from the US. This is how two combat aircraft projects emerged: the KAI FA-50 light fighter, based on the T-50 training aircraft and whose operators and buyers include South Korea, Poland, the Philippines, and Malaysia, and the KF-21 Boramae multirole fighter, a joint project with Indonesia.

The KF-21 is South Korea's alternative to the F-35, although it is not strictly a stealth fighter. It made its first flight on July 19, 2022, and its initial batch, Block I, is expected to be something intermediate between the 4, 5, and 5 generations of fighters. In fact, the KF-21 Block I will not have an internal weapons bay, which increases its radar signature. The internal bay is expected to be incorporated in the Block II version, and full stealth capabilities are expected to be obtained in the Block III version.

Unlike the F-35A, which is a single-engine aircraft, the KF-21's powerplant consists of two General Electric F414-GE-400K turbofan engines. These engines lack thrust vectoring nozzles, so the aircraft is not as maneuverable as the F-22, although they are externally similar. Additionally, unlike the F-35, the KF-21 has a two-seat version for conversion training.

Otherwise, the KF-21 is slightly larger than the F-35: it measures 16.9 meters long and has a wingspan of 11.2 meters. In terms of performance, it is very similar to its American competitor: it reaches a speed of 2,200 km/h (Mach 1.8), with a combat range of 1,000 km. The KF-21 carries a 20 mm M-61 Vulcan internal rotary cannon. In addition, it has ten weapon mounts that allow it to carry air-to-air missiles (the Meteor and IRIS-T, among others), air-to-surface and anti-ship missiles, and conventional and guided bombs.

The KF-21 is scheduled to enter service with the ROKAF in 2026. South Korea has already contracted a first batch of 40 Block I fighters, to which 80 KF-21 Block II aircraft will be added, with the first deliveries in 2032. This week, a KF-21 put on a spectacular aerial display at the defense event Seoul ADEX 2025. Japanese YouTube channel Tonk298 posted this video of the display yesterday:

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Main image: Tonk298