A homegrown KF-21 fighter prototype achieved supersonic speeds in a test flight Tuesday, South Korea’s state arms procurement agency said, in a key milestone for the high-profile warplane development project. The prototype flew for 56 minutes after taking off from the Air Force’s 3rd Flying Training Wing in Sacheon, about 300 km south of Seoul. It made its maiden flight in July last year. The first KF-21 prototype reached the speed of Mach 1, or 1,224 kilometers per hour, at an altitude of 40,000 feet at 3:15 p.m. as it flew over the country’s southern waters, according to the Defense Acquisition Program Administration (DAPA).
“Through the success in the supersonic-speed flight, our military further solidified the foundation to construct a robust military based on science and technology. We also took one step further to the goal of becoming the world’s fourth largest defense exporter,” Minister of National Defence of South Korea Defense Minister Lee Jong was quoted by DAPA as saying.
Securing the supersonic capability is a major part of the development efforts, led by its manufacturer, Korea Aerospace Industries Ltd., as it means key functions work smoothly irrespective of flight speeds. DAPA said it confirmed the “structural stability” of the KF-21 aircraft during the supersonic flight, while emphasizing the feat as being based on domestically developed technologies. Three KF-21 prototypes have so far conducted more than 80 flight tests to expand its capabilities in terms of altitude, speed and other elements. DAPA has said it plans to use a total of six prototypes, including the three, to conduct some 2,000 flight tests in total by February 2026.
The KAI KF-21 Boramae (formerly known as KF-X) is a South Korean-lead fighter aircraft development program with the goal of producing an advanced multirole fighter for the South Korean and Indonesian air forces. The airframe is stealthier than any fourth-generation fighter, but does not carry weapons in internal bays like fifth-generation fighters, though internal bays may be introduced later in development. It was officially given the name Boramae. At least 40 aircraft are planned to be delivered by 2028, with South Korea expecting to deploy a total of 120 of the aircraft by 2032.