South Korea Converting KF-21 Jet into 5th-generation Fighter

South Korea is getting ready to transform its locally developed KF-21 Boramae fighter jet into a fifth-generation stealth aircraft, whose development will be funded under the country's 2026 defense budget.

The Ministry of Defense also committed close to $62 million for local jet engine development and $453 million for sensor technology and radar-absorbing materials. The new 16,000-pound turbofan engine under development by Hanwha Aerospace and Doosan Energy may supplant the U.S.-built GE F414-GE-400K if it works out. Testing of a smaller 5,500-pound model is scheduled to commence towards the end of this year.

Korea Aerospace Industries (KAI), the producer of the jet, is finishing Block I development in 2026. Block II will extend air-to-ground capability testing, and Block III—due to mirror the stealth profile of the U.S. F-35 Lightning II—will feature internal weapons bays, embedded electronic warfare systems, and an internal optical targeting system.

The Block III variant is set to accommodate four Meteor-class air-to-air missiles or guided munitions inside the fuselage, lowering its radar cross-section by a substantial degree. South Korea is also developing a new long-range air-to-air missile with a budget of $5.4 billion. Authorities have said that the system is set to surpass the AIM-120 AMRAAM's terminal phase performance.

The KF-21 upgrade will have the ability to partner with unmanned vehicles. There will be a high-speed data link that will enable the manned aircraft to command drone swarms, allowing drones to make attacks in contested areas as the jet keeps a safe distance.