June 12, 2021 by Gastón Dubois
In an atypical event, Korean Aircraft Industries (KAI) invited journalist Kim Jae-seob from Hankyoreh newspaper to visit the KF-21 Boramae production line.
It is the first time that a newspaper has access to the site.
According to Hankyoreh, his journalist visited KAI’s factory in Sacheon, South Gyeongsang province, where the assembly line for the KF-21 Boramae prototypes is located.
The first prototype of the new and most advanced Korean fighter had its rollout on April 9, in a very showy ceremony, attended by important officials, including the President of the Republic of South Korea, Moon Jae-in, the Minister of Indonesian Defense Frabower Subianto, Defense Minister Seo-wook Kang Eun-ho, Director of Defense Acquisition Programs Administration (DAPA) and KAI President Hyun-ho Ahn.
The next five prototypes are being assembled on the assembly line, with their “guts” exposed. According to Kim Jae-seob, the second prototype is currently being tested to see if the missiles can be loaded properly.
The KF-21 Boramae assembly line goes public for the first time
The aircraft prototypes are made to run various tests, including flights, before the aircraft enter mass production.
Airplanes are opened and disassembled to repair or replace faulty parts and then reassembled for further testing, a process that is repeated over and over again.
Before the prototype aircraft can be approved for a test flight, it has to go through a year or so of ground testing.
Most of the assembly process is done by hand. Twenty engineers were working together to load missiles onto the second prototype aircraft.
“You may have imagined the kind of conveyor belt you might see on an automobile assembly line, but this is completely different,” said Kim Jun-myeong, head of KAI’s operations department, with a smile.
“Airplanes cannot be welded because they are made of aluminum and other special materials. We assembled the fuselage and attached the wings to the fuselage by drilling many holes on both sides to insert rivets. A single wing requires more than 10,000 rivets, ”said Lee Il-woo, senior engineer on the KF-21 project.
The journalist comments that he runs his hand over the gasket and the rivets, finding them extremely soft to the touch. If a rivet were to protrude even one millimeter from the surface, it would create air resistance.
“The interior of the fighter has a complex lattice design, intended to continue to function even if parts are damaged by gunfire during a dogfight. Electronic equipment runs from the cockpit to the wingtips, ”added Lee.
There are nine interconnected fuel tanks in aircraft, all of which are designed to be controlled electronically from the cockpit.
The prototype’s half-finished electronic devices were connected by cables of various lengths and thicknesses, running through conduits in the framework, sometimes bundled together and sometimes separated. Some of the cables were tied together at intervals of one to two centimeters and firmly attached to the frame of the fuselage truss.
“Because the fighter is so fast and has to repeatedly jump up and down, any slack in the wiring will make noise and cause damage,” said engineer Lee.
There are orders for a total of 170 KF-21 Boramae fighters. KAI plans to go into mass production in mid-2024, by which time all tests, tests and certifications have been passed.