[Science World] Conditions for Domestic Production of the 'Heart' of Korean Fighter Jets

There is frequent talk about the need to domestically produce the engine for the Korean fighter jet ‘KF-21.’ Many believe that while the entire aircraft system was developed domestically, the engine is still dependent on imports. In fact, the engine is also being manufactured domestically. The engine used in the KF-21 is the ‘F414-400k’ model developed by the American company General Electric (GE), which is almost the same as the one used in the FA-18E/F Super Hornet fighter jets operated by the U.S. Navy on aircraft carriers. This engine is produced under license by Hanwha Aerospace (Hanwha).

Of course, it is desirable to quickly move beyond mere licensed production. However, this is not an easy task. Aircraft engines, especially fighter jet engines, are products of precision engineering. Gas turbine engines used in aircraft, particularly in fighter jets, are exposed to extremely high temperatures and pressures. The turbine at the front rotates to draw in air, which is then mixed with fuel and ignited, producing high-pressure gas that propels the aircraft through the sky. Fighter jets require an ‘After Burner’ function to increase thrust by more than 50% by injecting fuel again into the exhaust gas from a single combustion and igniting it. At this time, the flame temperature rises to nearly 2000 degrees Celsius. Naturally, the engine’s lifespan is drastically reduced.

To solve these problems, advanced material technology is essential. It is known that more than 60 types of materials are required for developing advanced engines. To independently develop an engine, these materials must be developed domestically first, along with various processing technologies such as design, casting, forging, coating, and welding tailored to these materials. There are only a few places in Korea conducting such research. These include national research institutes like the Agency for Defense Development and the Korea Aerospace Research Institute, with Hanwha being a representative among private companies.

The immediate goal for researchers is naturally the domestic production of the ‘KF-21’ engine. However, there is a long way to go. The thrust of the F414-400k engine used in the KF-21 is 22,000 lbf (pound-force, a unit of thrust), and two of these engines are used to produce a total thrust of 44,000 lbf. Currently, the only gas turbine aircraft engine under development domestically is a 5,500 lbf-class engine led by the Defense Acquisition Program Administration. This means that Korea is only now developing an engine with about one-third the thrust of the KF-21 engine. The future battlefield is expected to be dominated by unmanned aerial vehicles (UAVs), which will require engines with thrust exceeding 10,000 lbf. Therefore, there is an urgent call to develop a 15,000 lbf-class engine that can be widely applied to various UAVs. Subsequently, by steadily improving performance based on this, it is believed that developing a high-performance engine with more than 22,000 lbf thrust applicable to the KF-21 will be possible.

One point that must not be overlooked in this process is durability. Communist countries like Russia and China can manufacture aircraft engines. However, only about three companies?the American GE and Pratt & Whitney (P&W), and the British Rolls-Royce?can produce ‘commercially viable engines.’ For fighter jet engines, those made by Russia or China have a usage time of about 1,000 hours, whereas products from the three U.S.-U.K. companies exceed 4,000 hours and can reach up to 6,000 hours. Typically, a fighter jet’s lifespan involves about 7,000 to 8,000 flight hours over approximately 30 years of operation. In other words, fighter jets made in communist countries require frequent engine replacements, which inevitably reduces their export competitiveness. For the Korean fighter jet to stand out in the global market, this challenge must be addressed. Even if it takes more time, now is the moment to devote more effort to developing fundamental material technologies. Only then can true independence in aircraft technology be achieved.

Jeon Seung-min, Science and Technology Writer