On the 6th at Hanwha Aerospace's Changwon Plant 1 in Changwon, South Gyeongsang. The first prototype of a 5,500 lbf (pound-force) class unmanned aircraft engine developed with domestic technology was on display on stage for a ground test kickoff ceremony to be held on the 7th. Pound-force is a unit of engine output, meaning the force to push 1 pound (453 g). A 5,500 lbf-class engine, in simple terms, can lift up to 2.5 t (tons).
The displayed 5,500 lbf-class engine was about 2 m in length, with an air intake diameter of 60 cm. In the 1980s, it was used in advanced trainer aircraft (manned) that measured 12 m in length and weighed 9.1 t (tons). As manned aircraft have grown larger, it is now classified as an engine used for unmanned aircraft.
The 5,500 lbf-class unmanned aircraft engine is the first long-life engine (usable for thousands of hours) prototype developed with domestic technology. The Agency for Defense Development (ADD) began designing it in 2013, and in 2019 Hanwha Aerospace launched full-scale development, completing the prototype. Starting this day, it is set to go through ground tests and other steps to be developed into finished goods.
Based on this engine technology, Hanwha Aerospace and ADD aim to independently develop an advanced 16,000 lbf-class fighter jet engine by the 2040s. It marks the first step toward self-reliance in aircraft engines.
◇10-year, 2 trillion won investment… built competitiveness for aircraft engine self-reliance
Hanwha Aerospace has invested nearly 2 trillion won in Changwon Plant 1 over the past 10 years to develop the prototype of the 5,500 lbf-class unmanned aircraft engine. Cumulative investment from 2015 through last year totaled 1.8 trillion won, of which 1.33 trillion won was spent on facilities.
By expanding investment, Hanwha Aerospace has steadily improved the quality of the F414 engine (for the Korean fighter KF-21) and F404 engine (for the light attack aircraft FA-50), which are produced under foreign corporate licenses, while securing prototypes of the 5,500 lbf-class unmanned aircraft engine developed with domestic technology and a 1,400-horsepower turboprop engine. The engine prototypes reportedly delivered stable performance in tests conducted after assembly.
The 5,500 lbf-class unmanned aircraft engine is slated to be mounted on a low-observable unmanned teaming aircraft currently under development by Korean Air Lines. Characterized by a reduced probability of detection, the low-observable unmanned teaming aircraft will carry out missions in a manned-unmanned teaming formation with the KF-21. The 1,400-horsepower turboprop engine aims to replace a Canadian engine mounted on medium-altitude reconnaissance unmanned aircraft.
◇Data and precision are the secrets to engine quality
When we visited the "Jet 2 test room" inside the engine test cell at Changwon Plant 1 that day, an F404 engine came into view. Firmly fixed to a blue structure connected to the ceiling, it was suspended about 2.5 m above the floor. Between the semi-circular mesh air intake, the intermediate stages where air is combusted, and the end-stage afterburner, countless wires and cables were connected.
The blue structure connected to the engine is a test adapter. When the engine is started, it generates forward thrust, and the adapter holds it in place. Numerous sensors are attached between the test adapter and the engine. Through this, all data generated as the engine starts, accelerates, decelerates, and stops are converted into digital signals and sent to the control room's computers.
In the control room, engine performance is monitored in real time through eight monitors. Test runs of the 5,500 lbf-class unmanned aircraft engine were also conducted here in the same manner over 10 days.
There are eight more such test rooms within Hanwha Aerospace's Changwon Plant 1. Seven indoors and two outdoors, for a total of nine. The F414 engine mounted on the Korean fighter KF-21, the F404 engine for the FA-50 light attack aircraft, and engines for various guided missiles have all gone through these test rooms. As this is where the final completeness of the engine is verified, it is the core space of Hanwha Aerospace's aircraft engine business.
Accuracy and precision are critical for assembly quality in engines. That is because it is important to ensure the engine consistently delivers the same performance. If the tightening level of a single bolt-and-nut set differs even slightly, it causes a significant performance gap. The F404 engine alone contains as many as 1,700 parts, and depending on the part, precision at the 1-micrometer (μm; 1 μm = one-millionth of a meter) level is required.
To reliably maintain quality, Hanwha Aerospace has introduced torque wrenches. They are used to apply a uniform force (torque value) to bolts and nuts. The status is indicated in different colors depending on the tightening level—green means a normal fastening, and red means it must be redone. Infrastructure is also in place to check production progress, process omissions, and delivery delays.
Kim Seung-su, production technology team leader at Hanwha Aerospace's Changwon Plant 1, said, "It took two years to establish these assembly procedures," and noted, "It is also a key to quality stability because it allows us to find the cause when problems occur."
◇Korea has long-life aircraft engines… exports and industry also expand
The government and corporations are staking everything on independent engine development to build the domestic industrial ecosystem and secure export competitiveness. Aircraft engines are a core component that determines an aircraft's performance and operational range. Major countries such as the United States strictly control technology transfers or exports through regimes such as the MTCR (a pact to prevent the proliferation of aircraft engines), citing the need to prevent leaks of advanced technologies.
Domestic engines are also expected to contribute to expanding the industrial ecosystem. If aircraft, engines, avionics, and armaments are vertically integrated, not only will export competitiveness rise, but value added can also be increased in maintenance, repair, and overhaul (MRO) businesses.
Kim Jong-ho, head of the advanced engine business team at Hanwha Aerospace, said, "It is unclear whether Korea will be able to produce engines domestically using foreign licenses even as it advances to the latest (sixth-generation) fighter jets," and emphasized, "Considering the recent case in which the United States refused European sales of F-35 fighter jet engines, independent development is ultimately essential in the future aerospace systems industry."