KAI KF-21 Boramae (Project KF-X)


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Dec 6, 2017
Republic of Wadiya
The KAI KF-21 Boramae (formerly known as KF-X) is a joint South Korean/Indonesian 4.5 generation fighter aircraftdevelopment program with the goal of producing an advanced multirole fighter for the South Korean and Indonesian air forces. The airframe is stealthier than other fourth-generation fighters, but does not carry weapons in internal bays like fifth-generation fighters, though internal bays may be introduced later in development.
Quick Facts KF-21 Boramae, Role ...
KF-21 Boramae
side view of a jet fighter model
KAI KF-X miniature at Seoul ADEX 2017
RoleBlock 1: Air superiority fighter
Block 2:
Multirole combat aircraft, air superiority fighter
National originSouth Korea/Indonesia
ManufacturerKorea Aerospace Industries
Design groupAgency for Defense Development
First flight2022 (planned)
Introduction2026 (planned)
Primary usersRepublic of Korea Air Force(intended)
Indonesian Air Force(intended)
Number built4 prototype(s)
The program is led by the South Korean government, which holds 60% of the program's shares. Indonesia took a 20% stake in the program in 2010, and the remaining 20% is held by private partners including the manufacturer
Korean Aerospace Industries (KAI). The KAI KF-X is South Korea's second domestic fighter jet development program, following the FA-50.
In April 2021, the first prototype was completed and unveiled during a rollout ceremony at the headquarters of KAI in Sacheon. It was officially given the name Boramae (Korean: 보라매, literally 'young hawk' or 'eyas'). The first test flight is anticipated in 2022, with manufacturing scheduled to begin in 2026. 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. It will also be available for export market.
In Indonesia, the KF-X development program is referred to as the IF-X program. The Jakarta Globe reported that the completed aircraft will receive the designation F-33.


The KF-X advanced multirole jet fighter project, intended to produce modern warplanes to replace South Korea's aging F-4D/E Phantom II and F-5E/F Tiger II aircraft, was first announced in March 2001 by South Korean President Kim Dae-jung at a graduation ceremony of the Korea Air Force Academy.Research and development (R&D) requirements were determined by the Joint Chiefs of Staff in 2002.: 18  The project was felt to be extremely ambitious, with the Korea Institute for Defense Analyses (KIDA, a defense ministry think tank) doubtful of the country's ability to complete the complicated project

Design and development​

The KF-21 production line

The initial goal for the program was to develop a single-seat twin-engine multirole fighter with stealth capabilities exceeding both the Dassault Rafale and Eurofighter Typhoon but less than those of the Lockheed Martin F-35 Lightning II. The Weapon Systems Concept Development and Application Research Center of Konkuk University advised that the KF-X should be superior to the F-16 Fighting Falcon, with 50% greater combat range, 34% longer airframe lifespan, better avionics, active electronically scanned array (AESA) radar, more-effective electronic warfare, and data link capabilities. Their recommendations also specified approximately 50,000 pounds-force (220,000 N) of thrust from two engines, supersonic interception and cruising capabilities, and multi-role capabilities. The project requirements were later downgraded by the Republic of Korea Air Force (ROKAF) to a 4.5 generation fighter with limited stealth capabilities.

South Korea possessed 65% of the necessary technology to produce the KF-X, and sought cooperation from other countries. To facilitate technology transfer, the Agency for Defense Development (ADD) proposed two primary concepts for the KF-X: C103, which resembled the F-35; and C203, which resembled European fighters with forward canards (the design chosen would depend on whether a development deal was reached with the US or European partners).

The C501 (a.k.a. KFX-E) was a third design, proposed by KAI and supported by the Defense Acquisition Program Administration (DAPA), which attempted to reduce costs with a smaller, single-engine fighter, but it had inferior performance to the F-16 and was unsuitable for the large airspace of Indonesia. ROKAF preferred the benefits of a twin-engine design, with better combat performance and safety, and a larger airframe with room for upgrades. These upgrades could lead to a future reclassification as a fifth-generation fighter, while the C501 was closer to fourth generation.

In 2014, the C103 configuration was chosen and Lockheed Martin agreed to transfer two dozen F-35A technologies as part of a purchase deal. However, the US government blocked the transfer of four vital technologies: AESA radar, infrared search and track (IRST), electro-optical target tracking devices, and radio jammer technology. South Korea was thus required to develop these technologies domestically. A 2015 audit estimated that 87% of technologies for the project had been secured.: 23  The preliminary design was finalized in June 2018. In September 2019, a critical design review examined 390 technical data sets and confirmed that the KF-X was adequate to ROKAF's requirements.

Estimated cost
[citation needed]KAI KFX-EADD C103ADD / KAI C105ADD / KAI C109
Empty weight9,300 kg (20,500 lb)10,900 kg (24,000 lb)11,100 kg (24,420 lb)11,800 kg (26,000 lb)
Max weight20,900 kg (46,000 lb)24,000 kg (53,000 lb)24,500 kg (53,900 lb)25,400 kg (56,000 lb)
Internal fuel3,600 kg (8,000 lb)5,400 kg (12,000 lb)5,400 kg (12,000 lb)5,400 kg (12,000 lb)
Wingspan9.8 metres (32 ft)10.7 metres (35. 2 ft)11.0 metres (36. 08 ft)11.2 metres (36. 75 ft)
Length15.2 metres (50 ft)15.7 metres (51. 3 ft)16.0 metres (52. 49 ft)16.9 metres (55. 4 ft)
Wing area37.1 square metres (399 sq ft)42.7 square metres (460 sq ft)42.7 square metres (460 sq ft)46.5 square metres (501 sq ft)
Engine1 × P&W F100 or GE F1102 × EJ200or GE F4142 × GE F4142 × GE F414
Weapons bayNoneSpace providedSpace provisionSpace provision


R&D expenditures​

A 2015 government audit placed the development cost of the project at 8.8 trillion: 18  (equivalent to ₩9.06 trillion or US$8.01 billion in 2017). In an agreement signed at the end of 2015, Indonesia agreed to provide 20% of the development costs, KAI would provide an additional 20%,[citation needed]and the Korean government would support the remainder.[better source needed]

More information Calendar Year, Expenditures on R&D ...
Expenditures on R&DTotalRef

44 billion (US$39.06 million)11 billion (US$9.77 million)55 billion (US$48.83 million): 21 
More information Calendar Year, Expenditures on R&D ...
Full Scale Development
Expenditures on R&DTotal
201555.2 billion (US$48.8 million)??
201667 billion (US$57.74 million)??
2017303 billion (US$268.04 million)??
2018435.3 billion (US$395.55 million)??
2019664 billion (US$569.78 million)??

Project partners​

While KAI was the primary builder, numerous other domestic and foreign companies were contracted to provide aircraft components or support. Several of these firms had worked with KAI on the T-50. For certain sensitive technologies, foreign companies only consulted for testing support in order to avoid arms-trading restrictions.

Hanwha Techwin signed an agreement with General Electric to manufacture General Electric F414 engines for KF-X aircraft. According to the contract, Hanwha is to manufacture key parts, locally assemble the engines, and oversee the installation of the engine on the aircraft. The company will also support flight testing and build an extensive support system for the aircraft's operations.

A Defense News report stated that the AESA radar would be a particular challenge; it was developed by Hanwha Systemswith assistance from other domestic firms and support from foreign companies. Elta Systems helped to test the prototype AESA, and Saab worked with LIG Nex1 on software development and evaluation.

In addition to working on the AESA, LIG Nex1 is to develop a radio jammer.

US aerospace contractor Texstars was selected by KAI to develop canopy and windshield transparencies for KF-X. Under the contract, Texstars will work alongside KAI to provide the KF-X fighter with birdstrike resistant transparencies with high-quality optics.

Triumph Group was selected by KAI to provide airframe mounted accessory drives (AMADs) for the KF-X. Triumph will develop and manufacture the AMADs, which transfer engine power to other systems.

Aeronautical Systems [es] (Spanish: Compañía Española de Sistemas Aeronáuticos, CESA), a subsidiary of Héroux-Devtek, was contracted to develop the emergency braking system.

United Technologies announced in February 2018 that it was providing the environmental control system, including cabin pressurization and liquid cooling systems, as well as the air turbine starter and flow control valve.

Martin-Baker was contracted to provide the Mk18 ejection seat escape mechanism.

Cobham received contracts to provide missile ejection launchers, communications antennae, external fuel tanks, and oxygen systems.

Meggitt was contracted to provide a wheel braking system,standby flight displays, and internal sensors including a fire detection system.

MBDA was contracted to integrate the Meteor beyond-visual-range air-to-air missile (BVRAAM) onto the aircraft.

Elbit Systems was contracted by Hanwha Systems to provide terrain-following/terrain avoidance (TF/TA) systems for the aircraft.

Curtiss-Wright was contracted by KAI to Provide complete flight test instrumentation (FTI) system, it is data acquisition system (DAS) for use in flight-test campaigns.


In February 2019, KAI began production work on the KF-X prototype, with six expected to be completed in 2021. These are to undergo four years of trials, and complete the development process by mid-2026. The first prototype was publicly rolled out on 9 April 2021; in addition to the six aircraft for airborne tests, two will be made for ground tests. DAPA anticipated a first test flight in 2022.


Data from Defense Acquisition Program Administration (DAPA)[better source needed]

General characteristics


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Meet South Korea's New KF-21 "Hawk" Indigenous Fighter​

Developed under an ambitious timeline, the fighter will complement F-35s and older fighters as part of a revamped Republic of Korea Air Force.​


THOMAS NEWDICKView Thomas Newdick's Articles
South Korea has rolled out the first prototype of its next-generation indigenous fighter, previously referred to as the KF-X, and officially named it the KF-21 Boramae, meaning hawk in Korean. The jet, South Korea’s most ambitious yet, is expected to fly next year and the country’s president has confirmed a demanding schedule to complete the development program for the initial version of the aircraft by 2026.
The Republic of Korea Air Force (ROKAF) is expected to induct 40 KF-21s by 2028 and have the full fleet of 120 aircraft deployed by 2032. The aircraft are urgently required to replace aging F-4E Phantom II and F-5E/F Tiger II fighters and are intended to complement F-35A stealth fighters—60 of which are being procured from the United States—as well as older F-15K Slam Eagle and F-16C/D aircraft.

A ROKAF pilot disembarks the first prototype KF-21 at today’s ceremony in Sacheon.
The rollout ceremony took place today at the Korean Aerospace Industries (KAI) facilities in Sacheon, South Gyeongsang province, and saw an address by President Moon Jae In. He heralded “a new era of self-defense,” and “a historic milestone in the development of [South Korea’s] aviation industry. Moon also set a goal for South Korea to become the world’s seventh-biggest aviation industrial power by the 2030s.

Full-scale development work on what was then known as the KF-X began in 2015 and in 2019 South Korea’s Defense Acquisition Program Administration (DAPA), which manages defense procurement, announced the go-ahead for the construction of a prototype. Last September, KAI announced that the final assembly of the prototype fighter was underway, mating the fuselage sections and wings.



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Dec 6, 2017
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The Korea Fighter eXperimental Aircraft is to be indigenously developed and Hanwa System is to supply key onboard elements including AESA Radar, EOTGP (EO Targeting Pod), IRST (Infra Red Search and Tracking), SMC (Stores Management Computer), ACCS (Audio Communication Control System), MFD (Multi Function Display), MC (Mission Computer) and the RF Jammer.

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Korea’s biggest domestic weapons project takes off​

테스트사진 크게보기
The biggest homegrown weapons development project in Korean history is about to take off as Seoul begins production for its new cutting-edge, multi-role fighter jets known as the KFX.

The design for the KFX, which stands for Korean Fighter Experimental, is the result of almost two decades of planning that cost the government approximately 8.6 trillion won ($7 billion). Once production begins on 120 units of the new jet, which is scheduled to start in 2026, an additional 10 trillion won will be needed, putting the bill for the entire project at around 18.6 trillion won.

The Defense Acquisition Program Administration (DAPA), Korea’s arms procurement agency, concluded its three-day critical review of the jet’s design last week, giving its final approval on Friday. Production of a prototype model begins this month.

According to Ryu Kwang-soo, head business manager of the KFX project at Korea Aerospace Industries (KAI) - the project’s main developer, around 9,300 out of the approximately 12,000 detailed blueprints needed for the KFX project are complete - 78 percent of the project, including key components.

As a major national project, development for the KFX was led by the government’s Agency for Defense Development (ADD) and KAI, but approximately 225 private firms also partook in the process, including all of the country’s major defense contractors. Foreign stakeholders in the project include Indonesian Aerospace and the U.S. company Lockheed Martin, which provided technical assistance and several pieces of technology integral to the jet’s development.

The KFX, a twin-engine fighter superior to the U.S.-built F-15, is set to replace the Air Force’s fleet of F-4 and F-5 fighters that were first purchased in the 1960s. By the time the first units of the jet are operationally deployed in 2026, the military capacity of Korea’s Air Force will have advanced leaps and bounds.

While the KFX is classified as a 4.5-generation fighter with avionic and strike capabilities upgraded from the fourth-generation of combat aircraft built since the 1980s, it already possesses several stealth features and superior performance that could, with upgrades, possibly put it on par with the latest fifth-generation stealth aircraft.

테스트사진 크게보기
Top: The AESA radar to be equipped on the KFX, as revealed by the Agency for Defense Development last Thursday. Above: A scaled-down module set of the same AESA radar, smaller than a person’s fist. [AGENCY FOR DEFENSE DEVELOPMENT]
KAI has been reluctant to reveal precisely what type of stealth mechanisms the jet is equipped with, but its radar cross section (RCS) - the primary measure of stealth on military aircraft - measures only 0.5 square meters (5.4 square feet). The smaller the RCS is, the stealthier the aircraft.

According to GlobalSecurity.org, a military data website, the U.S. Navy’s F/A-18E/F and France’s Dassault Rafale jets have an RCS of 1 square meter, the F-15 has 25 square meters and the fifth-generation F-35 has just 0.005 square meters.

To allow the jet to hold such equipment, KAI designed the KFX’s fuselage to resemble a stealth jet akin to Lockheed Martin’s F-22. Most of the sensors are located inside the aircraft, while the four air-to-air missiles installed on the KFX are half buried in the central part of the fuselage. Space was also left on the aircraft for the future installation of an internal weapons bay - a characteristic component of stealth fighters.

According to one KAI spokesperson, once the KFX’s stealth capacity is enhanced, it will be comparable to the F-117 - Lockheed Martin’s famed stealth attack aircraft that outclasses the F-35 in numerous ways.

Capable of performing sharp maneuvers midcourse, the KFX jet is already set to be equipped with a host of cutting-edge equipment that makes it one of the world’s finest non-stealth combat aircraft.

It far outmatches any aircraft owned by North Korea, which still largely operates Soviet models, as well as even those of China or Japan. In the event that aerial warfare breaks out in Northeast Asia, the Korean Air Force’s F-35As are set to face off against the enemy’s stealth aircraft, while its KFX and F-15K jets can hold off any hostile non-stealth aircraft. Once the KFX is upgraded in terms of its stealth functions, foreign powers may find it difficult to challenge Korea’s dominance over its own skies.

When development began on France’s Dassault Rafale or the U.S. F-35 jets, the novelty of the technology inflated costs and caused several difficulties,” said Jeong Gwang-seon, the head of the KFX business project at DAPA. “We had an advantage when developing the KFX, since we could refer to these advanced countries’ technology and development process.”

Given that it was designed with export in mind, around 65 percent of the jet’s components are domestically produced. While a single unit of the jet is currently estimated to cost around 80 billion won to build, producing a larger volume could mean these costs could lower over time.

Exporting the jet and its key components could also open the doors to a variety of new opportunities for Korea’s defense industry. In particular, the country is moving toward domestic development for its air-to-air and surface-to-air missiles - a key part of its defense strategy against North Korea’s advancing missile program - through the experience it has gained through the KFX program.

Lee Il-u, a managing director at KAI who led the development of the KFX’s fuselage, said the project allowed Korea’s development capacity for combat aircraft to “advance beyond” that of Britain or France.

But the path to get here was by no means smooth. In 2001, former President Kim Dae-jung promised that Korea would begin developing its own next-generation fighter jets, but the 13 years since were wasted. Five separate feasibility studies were conducted by relevant organizations, but few were willing to stake their careers on a project of such an astronomical cost and risk at a time when Korea lacked the necessary technology.

One of the biggest hurdles to the project came in 2015, when the U.S. government refused to allow the transfer of four of the 25 crucial technologies that Lockheed Martin agreed to provide Korea in exchange for Seoul’s purchase of its F-35 jets. Among these was an advanced radar system known as the Active Electronically Scanned Arrays, or ASEA, a game-changing component equipped in virtually all the latest generation military aircraft.

Conventional radars with rotating antennas can only perform one function per unit, so aircraft must be equipped with multiple radar units to be capable of a variety of tasks like surveillance and tracking. AESA radars, on the other hand, are made up of a thickly packed matrix of small transmit and receive modules (TRM) that allow them to put out differently shaped signal beams that can rapidly and simultaneously detect and track multiple targets in the air, at sea or on the ground.

Korea’s defense industry was thus forced to venture into terra incognita virtually blind in order to develop an ASEA radar for the KFX. The resulting domestically produced model has 1,088 TRMs compared to the approximately 1,200 TRMs on the F-35’s AESA radar.

“ADD had the technology but the firm [Hanwha Systems] had no experience in making the radar, so we were concerned,” said Shin Hyun-ik, a radar development director at ADD. “But we have now become the 11th country in the world to develop an AESA radar.” Even Israel’s ELTA Systems, a global leader in defense electronics, rated Korea’s AESA radar as superior to that of Israel’s.

A scaled down model of the AESA radar with 16 modules revealed by Hanwha Systems at its research center in Yongin, Gyeonggi, on Sept. 18 looked no larger than a fist. Yet it cost around 45 million won to build. Importing such a radar from abroad is estimated to cost around 80 million won. Close to 365.8 billion won has been invested into developing the AESA radar until 2026, but engineers have completed approximately 85 percent of its hardware. All parts of the radar will be produced domestically starting from next year. The radar will also be tested in Israel by next spring, followed by another flight test in Korea from next November. From 2023, it will be installed on the KFX prototype for a final round of testing.

The development of the aircraft’s fuselage and system integration was also an enormous task. According to Ryu, KAI had to revise blueprints put out by the ADD during the exploratory stage a total of nine times before getting something that was to their satisfaction. Another major problem they encountered was reducing the weight of the jet. The target weight for the KFX was 12.1 metric tons (13 tons), but designers had to reduce an additional 500 kilograms (1,102 pounds) to account for future additions. “So we opted to offer 100,000 won in incentives to every researcher who was able to take off a kilogram off the jet’s weight,” Ryu said. Equally complicated was the process of seamlessly integrating the approximately 230,000 component parts - minus the engine - into the aircraft’s design, a number far greater than the average car, which has around 20 to 30,000 constituent components.

At KAI’s factories in Sacheon, South Gyeongsang, around 1,250 researchers and engineers are hard at work developing the KFX. These professionals will also take on the role of transforming the jet into a stealth fighter, and eventually will begin preparations to work on the sixth-generation of combat aircraft. The KAI plans to release a prototype of the KFX by April 2021, and, after sufficient test flights, the first batch of eight jets are set to be delivered to the Air Force by 2026. Concerns remain, however, that the four-year duration reserved for flight tests may be insufficient to test out the weapon, since it is shorter than the five to eight years that advanced countries normally allocate for such testing.

BY KIM MIN-SEOK, SHIM KYU-SEOK [[email protected]]

South Korea unveils fighter jet mock-up amid program challenges​

By Josh Smith, Ju-min Park

SEONGNAM, South Korea (Reuters) - South Korea has displayed the first full-size mock-up of the KF-X fighter jet it is developing with Indonesia, after officials said the program passed key design reviews in September.

The next-generation aircraft being developed by Korea Aerospace Industries (KAI) is designed to be a cheaper, less-stealthy alternative to the U.S.-built F-35, and the plan is to eventually replace most of South Korea’s older fighter jets and produce more for export.
The mock-up was displayed on Monday at the Seoul International Aerospace and Defense Exhibition (ADEX).
South Korea has ordered 40 of the advanced F-35A aircraft from the United States, the first of which arrived this year.
North Korea has condemned South Korea’s purchase of the F-35s, as well as the development of other advanced weapons.

KAI is currently manufacturing a KF-X prototype and plans to carry out ground testing and flight tests in 2021 and 2022, respectively, company officials said.
“On the face of it they are making good progress, but there are signs of challenges in the program,” said Greg Waldron, Asia managing editor for FlightGlobal, a publication covering the aerospace industry. Among these are Indonesia’s push to renegotiate how it will pay its portion of the costs, and breaking into an export market crowded with established alternatives, Waldron said.
“With a program this ambitious you really have to spread the cost among many partners,” he said. “They could sell a few here and there, but the problem is they are going to be kind of late to the market and there are already many strong aircraft already out there.”
South Korean and Indonesia agreed in 2014 to jointly develop the KF-X in a project worth 7.5 trillion won ($6.33 billion) with Jakarta agreeing to pay 20% of the cost.

Last year, however, Indonesia sought to renegotiate to take pressure off its foreign exchange reserves and has since offered to pay its share of the cost in the form of a barter.

The KF-X program also hit a snag when South Korea was forced to develop several key technologies after the United States refused to provide approval for the use of some systems, like a radar, which is now being developed by Hanwha Systems.
But KAI says the project is progressing, and is helping South Korea build on its earlier aircraft programs.
“We could not have done KF-X if we did not have experience in building T-50 and FA-50,” a senior company official said, speaking on condition of anonymity as he was not authorized to speak to the media. “We are advancing step by step.”
Reporting by Josh Smith and Ju-min Park; Editing by Mark Potter
Our Standards: The Thomson Reuters Trust Principles.

ADEX: KAI unveils futuristic KF-X cockpit​

By Greg Waldron15 October 2019
South Korea's KF-X cockpit will have a full-panel touch screen that is integrated with the pilot’s helmet and head-up display.
South Korea's KF-X cockpit will have a full-panel touch screen that is integrated with the pilot’s helmet and head-up display.
A mock-up of the new cockpit for the developmental fighter at Korea Aerospace Industries' (KAI's) stand at the ADEX show in Seoul depicts a full, single-panel touchscreen display in place of traditional multi-function displays.
The display offers a full-range of tactical information, including radar tracks, weapons and engine status, and other key data.
K-FX cockpit mockup

The advanced cockpit of the KF-X
Greg Waldron/FlightGlobal
Unlike the touchscreens found in smartphones and tablets, the screen's buttons will require greater pressure for inputs, says KAI. This helps reduce tracking errors stemming from smudges and scratches.
Further, the cockpit will feature hands-on-throttle-and-stick functionality. This allows the pilot to operate key aircraft functions from the sidestick control column and throttle. This improves situational awareness, as it enables the pilot to keep his or her attention focused outside the cockpit.
KAI plans to roll out the first KF-X prototype in early 2021.

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Dec 6, 2017
Republic of Wadiya

Assembly Of First KF-X Prototype To Be Completed In Second Half Of 2020​



Korea Aerospace Industries (KAI) has announced that it plans for final assembly of its first prototype KF-X advanced multirole fighter to be completed in the second half of this year. The completion of the first prototype will allow for the rolling out of the prototype in 2021, and for its testing programme to begin.
In comments to the Korea Herald, a KAI official said: “to introduce a prototype next year, KAI is looking forward to a final assembly of the jet in the period.”
The KF-X had passed its critical design review in September last year, with the assembly of the first prototype beginning soon afterwards. Six prototype KF-X aircraft are set to be built for testing.
The announcement of the expected time of completion of the first prototype follows the delivery of General Electric F414-GE-400K engines that will be used to power the KF-X. 15 engines were delivered, with each of the six prototype aircraft using two engines. Three engines are being kept as spares.
The first bulkhead of the KF-X prototype at the ceremony commemorating its completion.
Al DiLibero, general manager of GE’s Medium Combat & Trainer Engines department, spoke on the delivery of the engines, saying:
“GE is thrilled to reach this important milestone in the KF-X program.
Our success so far on this program reflects the strong relationship between the ROKAF, our South Korean industry partners and GE Aviation, and the long and successful history of our engines powering ROKAF aircraft.”
Other ROKAF types powered by GE engines include the F-15K Slam Eagle, T-50 Golden Eagle, F-4 Phantom II and the F-5E/F Tiger II. The KF-X is intended to replace the Phantom II and Tiger II in South Korean service.

GE publicity video on the delivery of the F414 engines to Korea
The announcement of the timeframe for prototype completion is a bright spot amidst questions over the financing of the 18 trillion won ($14 billion) project. Indonesia has delayed payments for its share of development costs, having 500.2 billion won in overdue payments at the end of April. The lack of Indonesian collateral prevents South Korea from demanding alternative means of payment, although Indonesia’s current struggles with the Coronavirus pandemic would suggest that the odds of success, either way, may be extremely slim.



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Dec 6, 2017
Republic of Wadiya

LIG Nex1 delivers EW self-protection system prototype for KF-X fighter aircraft​

by Dae Young Kim

South Korean defence company LIG Nex1 has developed an electronic warfare (EW) self-protection system for integration with the Korean Fighter eXperimental (KF-X) fighter aircraft being developed for the Republic of Korea Air Force (RoKAF).

LIG Nex1 has delivered an internal EW self-protection system prototype for integration with the RoKAF’s future KF-X multirole fighter aircraft.  (LIG Nex1)

LIG Nex1 has delivered an internal EW self-protection system prototype for integration with the RoKAF’s future KF-X multirole fighter aircraft. (LIG Nex1)
Company officials told Janes that a prototype of the system was delivered to aircraft manufacturer Korea Aerospace Industries (KAI) in the second half of 2020 to equip the KF-X prototypes currently being assembled at KAI headquarters in Sacheon, South Gyeongsang Province. The first prototype is expected to be formally rolled out in April.

KAI expects to complete construction of the second and third KF-X prototypes this year and finish assembling the remaining three aircraft by the first half of 2022. The fourth and sixth prototypes are expected to be tandem-seat variants.

The officials said that the internal EW suite, which was developed under a KRW114.5 billion (USD101 million) contract signed in late October 2016, is expected to enter series production following a series of trials and evaluations.

On its website LIG Nex1 described the system, which it referred to simply as the “KFX EW Suite”, as an “EW self-protection jammer” that is designed to detect, analyse, and jam signals from enemy radars and/or incoming missiles. The suite will also be integrated with countermeasures and decoys on the KF-X, including chaffs and flares.


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Dec 6, 2017
Republic of Wadiya
Republic of Korea Armed Forces
about 2 years ago
New and old information about KF-X unveiled after the recent Critical Design Review (CDR) session.
1) 9,300 pages out of 12,000 pages of detailed blueprints have been completed, accounting for about 78% of detailed design process.
2) Although exact specification is classified, KF-X's Radar Cross Section (RCS) is said to be around 0.5㎡. According to Global Security, F/A-18E/F and Rafale have approximate RCS of 1㎡. F-15 has 25㎡while F-35 has 0.005㎡, respectively.
...See more
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Dec 6, 2017
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Aerospace / Induction Control
Korea's next-generation fighter, the KF-21 Boramae

2018. 7. 25. 21:52
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Text Other Features

The Korean Fighter eXperimental (KF-X) development project invested about 8.8 trillion won from 2015 to 28 to secure the air superiority in the defense sphere of the Korean Peninsula, and to achieve long-range precision strikes and land and sea infiltration forces. It is a project to develop a 4.5-generation medium-class fighter with the ability to neutralize the aircraft. Korea Aerospace Industries (LTD) is in charge of system development, and 16 domestic universities, 11 research institutes, and 553 partner companies participated in the development.

It is expected to be able to obtain effects such as preventing power void and securing air superiority, securing independent/economic performance improvement capabilities, strengthening aircraft export competitiveness, upgrading industrial structure, and establishing an efficient support system. Considering the replacement quantity of the KF-16, it is considered that up to 250 units or more will be introduced. For aircraft conversion training, some aircraft are introduced as two-seat aircraft.

Development Schedule

The KF-21 applies an evolutionary development strategy to minimize development risks, and in Block-I, it performs step-by-step development to secure basic flight performance and air-to-air combat capability, and in Block-II, air-to-ground and air-to-sea combat capability. In the system development stage, Block-I is developed from '15 to '26, and after about 4 years of initial flight test and follow-up flight test, it is verified whether the requirements are met and type certification is obtained. ' When the national defense standards are established, the system development is completed. Then, from '26 to '28, an additional armament test was conducted for two years to develop Block-II.

* System development (‘15~’26): KRW 8.1 trillion / Additional arms test (‘26~’28): KRW 700 billion


It measures 16.9 m (55.4 ft) in length, 11.2 m (36.7 ft) in width, and 4.7 m (15.3 ft) in height. The main wing area is 46.5㎡ (500ft²), the aspect ratio (A/R) is 2.7, and the front angle is 40˚. Range 2,900km (1,550nm), maximum speed Mach 1.8 (1,400mi/h), fuel payload about 5.4t (12,000lb), empty weight about 11.5t, maximum armament payload 7.7t (17,000lb), maximum take-off weight ( MTOW) is 25.6 tons (56,400 lb).

design development





Since 2004, the Defense Science Research Institute has been conducting research on design technology for fighter-class aircraft, and has accumulated data by conducting DMU (Digital Mock-Up) and miniature wind tunnel tests. Conducted an experiment on the effect of leading edge flap bending on aircraft supersonic cruise capability, scheduling rules and aerodynamic design for a canard-delta wing shape fighter-class aircraft, etc. The design was established.





The C100 / C200 design plan derived according to the results of previous studies was developed into C103 and C203 through the exploration and development carried out from 2011 to 2012. In the 3rd FX project, if an American-made fighter was selected, the diamond-shaped wing C103 would be adopted, and if a European-made fighter was selected, the C203 in the shape of a canard-delta wing would be adopted. C203, a canardwing shape, will be eliminated as it remains. Afterwards, the C501 and C103, which were derived from the C102E single engine design, competed, but at the 290th Joint Chiefs of Staff meeting, the key issue was to determine the engine type as a twin engine.


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After the exploratory development was completed, C104, the standard shape of the system development execution plan based on C103, was developed, and based on C104, the C105 shape was developed reflecting the improvement of the intake port performance, the front fuselage cross-sectional shape improvement, and the vertical tail/fuselage coupling structure improvement. . As the engine was confirmed, the air intake was enlarged and optimized according to the engine intake flow, and the wing surface load was reduced as the area of the main wing and tail increased to ensure excellent turning ability. Also, from the exploration development, the front landing gear was changed to fold backwards as the system development started, and this is also presumed to be due to the change in the arrangement of the internally mounted equipment.

KF-X C106
Rotary balance (BAR LAMP, Germany), subsonic force & moment (Korea Aerospace Research Institute KARI), transonic force & moment (UK ARA TWT), supersonic force & moment (France ONERA S2MA) tests by making a reduced model based on the C105 shape Insufficient deep stall recovery ability, insufficient lateral/directional stability, insufficient instantaneous turn rate, and reduced maximum flight speed due to increased supersonic drag. The C106 shape was developed with additional changes to the front fuselage for this purpose.


As the analysis results showed that the transverse/directional stability characteristics were unstable in a specific angle of attack region and the deep stall recovery ability was insufficient, a study was conducted to develop a shape with excellent static transverse/directional stability characteristics in the high angle of attack region. A wind tunnel test was performed on a combination of the front fuselage shape, wing shape and position, and vertical tail wing shape and position. In addition, the deep stall and transverse stability characteristics were improved by moving the vertical tail position outward, and the directional stability characteristics were improved by moving it more forward. Through these studies, the C107 shape was developed.

KF-X C107
For the C107, the shape of the vertical tail has been changed from a high-taper shape to a diamond shape to improve transverse/directional steering stability, and a glove shape has been added to the leading edge flap of the main wing. The intake performance was optimized by tilting the air intake at a lower half angle of 10˚, the RWR antenna and ECM antenna of the gun, the integrated electronic warfare system, and the sensors such as IRST and EOTGP were determined, and the boundary layer separator on the intake side and equipment cooling such as ECS The ram air intake design for

KF-X C108
With the transition to the C108, the layout of subsystems such as the APU exhaust gas outlet and control surface actuator was embodied and reflected in the shape. The glove added in C107 was removed again through wind tunnel testing and optimization, and the shape of the vertical fin was changed symmetrically. The RWR antenna, which was placed on the vertical tail, was relocated to the wingtip of the main wing, and the IFF antenna in front of the IRST and the ECM antenna on the side and bottom of the fuselage were additionally placed.

KF-X C109



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The final shape, C109, reflects design improvements to improve flutter margins. The better the flutter (vibration phenomenon occurring in the wing and fuselage of an aircraft) margin, the better the aeroelastic stability of the aircraft, making it possible to maneuver more stably at high-speed and high angle of attack. was divided into two to save weight and improve flutter margin. In addition, the engine was moved slightly backward so that the vertical fins covered the engine, which improved the low visibility of the infrared sensor from the side and improved the ECM antenna radome to protect it from flames. A ventilation hole is formed between the two engine nozzles to ventilate using low pressure generated between adjacent nozzles during engine operation. was reflected as




In the development of the T-50 system, tools in the form of executable files provided from abroad were used, but the tool localization was started and developed to a level that can be used for fighter-grade system development. A design tool was developed and utilized. Unlike the T-50, which required a relatively large amount of time and limited savings because it was optimized through repetitive design-analysis work based on the initial shape determined based on experiences and cases, the KF-X project was From the beginning of development, continuous weight reduction activities were required. In the structural optimization design work, work efficiency was increased by using the theory-based automated optimization shape derivation software, rather than engineer experience and cases. Established independent work procedures and started to operate the organization. In particular, in the C106 shape, the weight increased as the fuselage became larger. In order to reduce the weight by more than 500kg compared to the NTE (Not To Exceed) target weight of 12.1t, intense weight management and structural design optimization were made.

Using ASTROS (Automated Structural Optimization System), a commercial flutter optimization program, a structure with high sensitivity to the flutter speed improvement effect among horizontal fin structures was selected as a design variable, and an optimization design was performed to minimize the structure weight. Through this, the weight reduction effect of about 15.6% compared to the initial structural reinforcement plan was derived. In addition, the shape optimization of parts such as fittings was performed using the Hyperworks Optistruct structure optimization program. Through the comparison of the topology results and the relative weight through sizing, the spacing of main rigid members of the main wing, horizontal fin, and vertical fin The layout was optimized and reflected.





The fighter-grade wind tunnel test requires a vast amount of test time including subsonic, transonic, and supersonic speeds, force/moment test, inlet test (Isolated, Forebody), aerodynamic load test, rotary balance test, spin test, air data correction test , an external separation test is performed. Exhaust effect test for force/moment characteristic prediction including rear fuselage drag prediction according to the increased number of engines and vertical tail shape compared to T-50, and aerodynamic noise test including internal cavity shape were additionally performed, and it was possible to achieve high Mach number. Bleed accompanying inclined shock wave inlet for inlet, inlet test difficulty for bypass system design increased. New test techniques such as CBSTAT and FTR (Free To Roll) were used to identify the characteristics of AWS (Abrupt Wing Stall) that can be accompanied by high maneuvering, thereby reducing the risk of the flight test stage, and using 3D printing technology for rapid model production and small wind tunnel The test was usefully used in a number of offset studies for shape development optimized for steering stability and high angle of attack characteristics.

After the system development contract, KARI started the low-speed wind tunnel test on June 22, 2016, and confirmed the external design through the basic design review (PDR) on June 28, 2018, and detailed design review (CDR) on September 26, 2019 ), after the completion of the prototype production began. In addition, a wind tunnel test was performed with a confirmed shape until the production completion stage of the prototype, and the test to increase flight stability by confirming flight characteristics before actual flight was repeated. In order to secure detailed aerodynamic data on the confirmed shape by 2020, a total of 13,000 hours of wind tunnel testing was performed in a three-step process.

In the CFD part, it was used for analysis of flow characteristics, trade study support, and correction of wind tunnel test results, which are difficult to perform wind tunnel tests, by building a high-capacity HPC environment of 6,500 cores, using commercial S/W, and developing In-House Code. In particular, major design issues such as AWS analysis, horizontal/vertical tail buffett characteristics analysis, twin engine exhaust effect analysis, inlet shape and bleed/bypass system design/analysis, internal cavity aerodynamic noise analysis, armament separation analysis, and prediction of dynamic coefficients of steering stability contributed to the timely resolution of It was used not only for aerodynamic design, but also for detailed system design/analysis such as design load, internal heat flow, fuel, fire extinguishing, ventilation analysis, and injection system. In order to improve performance analysis and steering stability simulation accuracy, we developed a method of configuring the aerodynamic database with the improved thrust interlocking database in the F-16 and T-50, inlet, exhaust nozzle, bleed/bye by engine power condition. An aerodynamic database linked to force/moment changes through pass and secondary intake/exhaust ports was applied.


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In order to secure excellent fighter maneuverability in the transonic and subsonic regions, the KF-21 has applied an airframe structure design that reflects the requirements such as structural strength and durability to withstand high mobility loads. The aerodynamic design that can secure various mission performance capabilities with excellent maneuverability and high angle of attack characteristics was reflected. It is smaller and lighter than the F/A-18E/F using the same F414-GE-400 engine, the thrust-to-weight ratio is comparable to that of the Eurofighter Typhoon, and the wing load is lower than the F-35 of the same thrust. As these design elements, Nonlinear Dynamic Inversion (NDI) control method, triple digital FBW, LEX (Leading Edge eXtension), and variable camber blades are applied, high acceleration, turning ability, and high angle of attack maneuverability are improved. expected to show. The NDI control method is the second applied after the F-35 as a mass-produced aircraft, and it has a wide flight envelope by removing the aircraft's dynamic characteristics and designing the aircraft's response characteristics to provide an appropriate response according to the required performance. It is possible to secure uniform flight performance in the air, ensure the stability of the aircraft, and at the same time secure optimal maneuverability.



In Block-I, the Basic Flying Qualities and Air-to-Air Combat are secured, and the Stability and Control Augmentation System (SCAS) that secures basic flight performance and stability. This applies. In order to provide optimal maneuverability for each mission, the basic steering stability system is designed by dividing it into UA (Up and Away) mode, which is an air-to-air configuration, PA (Power Approach), which is a landing exterior shape, and an aerial refueling mode, which is an aerial refueling type. Reconfiguration Control for safe return to base by coping with failures of atmospheric sensors, control plane actuators and single engine to ensure aircraft stability, and Envelope Protection to prevent exceeding structural limits and flight areas ) control law is applied, and the representative flight area protection functions include a low speed warning and angle of attack limiter to prevent entry into a stall, and a pilot command limiter to prevent the restriction of the rescue limit value. There are limiters such as a limiter) and a spin protection device that prevents the aircraft from entering the stall when entering the stall. In addition, the Virtual Speed Brake technique that can decelerate the aircraft speed with a combination of control surfaces is applied.

Basic autopilot flight systems and automatic flight systems such as Automatic Terrain Following System (ATFS), Automatic Ground Collision Avoidance System (AGCAS) and Pilot Activated Recovery System (PARS) However, considering the development schedule, the flight test evaluation of the automatic terrain tracking and ground collision avoidance system is performed in Block-II. Flight control laws are being developed through international joint research and industry-university-research cooperation. The basic steering stability enhancement system will utilize existing technologies and study and apply various control methods through industry-university-research cooperation. In addition, it is developed through the opinions of domestic and foreign aircraft development expert groups and technical support from Lockheed Martin, which is supported by the FX 3rd Offset, and finally evaluated through flight test evaluation.

For the verification and evaluation of these flight control systems, the Iron Bird and Maneuverability Analysis Simulator (HQS) equipment were developed and constructed from April 2016. The Iron Bird is composed of four main sections: the hydraulic equipment room, the integrated control room, the iron bird room, and the HQS centering on the hull structure that mimics the shape of an aircraft. The airframe structure was manufactured close to the actual shape of the KF-21, and the hydraulic devices are connected to each control surface using links and torsion bars that have the same characteristics as the prototype of the aircraft. designed to do







In order to secure survivability on the battlefield in the future, a low-detection shape design including a reflection angle alignment design, buried antenna, S-Duct, flat fuselage, and semi-buried weapon window was applied, and through this, the F/A-18E/F Super Hornet A low RCS was achieved. RAM is applied to the canopy, main wing, and tail wing, RAS is applied to the ducts and flaps inside the fuselage, and frequency selective surface technology will be applied to the radome to prevent radar waves from enemy fighters from being reflected back to the antenna. . As for RAM, paint type and foam type are applied from the first mass production, and other technologies including sheet type RAM and RAS are applied to subsequent mass production. Some RCS reduction designs such as sawtooth treatment and conformal antenna were not applied, and due to RCS increasing factors such as external armament and external targeting pod, the low detection performance is evaluated as RO level.

ps. The detectability of a fighter is classified into MIN (Minimum Treatment) - RO (Reduced Observable) - LO (Low Observable) - VLO (Very Low Observable), and it is evaluated as a stealth aircraft from LO with an RCS of -20dBsm (0.01㎡). Most of the modern stealth fighters are VLOs with less than -30 dBsm (0.001 m2).



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In the case of the existing paint-type stealth material, there was a serious problem that the stealth performance was deteriorated or lost due to the interfacial separation problem due to the low bonding strength with the fighter body. In addition, since the existing radio wave absorbing materials were in the form of paints, there was a problem of performance degradation due to thermal deformation of radio wave absorbing paints due to low heat resistance when operating in a supersonic environment. In addition, there were problems that it took a long time to apply the radio wave absorbing paint, and it was difficult to maintain a constant performance due to the difficulty of uniform application, which was cited as the cause of the high operating and maintenance cost.

The film/prepreg type RAM being developed for KF-21 is a laminated radio wave absorbing material that is cured on a carbon fiber composite material. This is a technology similar to the Fiber Mat known to have been applied to the F-35. Instead of the conventional Ni-coated carbon fiber, Fe-based magnetic metal coating technology developed for the first time in the world is applied, so that it can exhibit high electromagnetic wave absorption at a low cost. By applying the same resin as the fuselage material (carbon fiber composite), superior durability was secured compared to conventional paint/paste type RAM, and the peeling problem was solved by securing superior interfacial strength of 40 MPa or more. In addition, by developing a sealant-type RAM, it is being developed to maintain and maintain performance degradation due to material damage or thermal deformation that occurs during fighter operation. In addition, an electromagnetic discontinuity occurs between RAM, RAS, and aircraft structures, which may increase RCS. Therefore, Material Transition materials applied to electromagnetic transitions are being developed.




Materials used for major parts were selected in consideration of performance and cost from the early stage of development. The body is composed of various metal and non-metal composites such as Ti-6Al-4V titanium alloy, aluminum 2024-T3, 2124-T851, 7050-T7451, and carbon fiber composite. 3D printing technology and diffusion bonding technology will be applied.

The aircraft is a semi-monocoque type with a modular design concept applied. It consists of a fuselage, a main wing and a tail wing, and the fuselage consists of three parts: the front fuselage, the center fuselage and the rear fuselage. There are two structural arrangements according to the single-seat and double-seat shapes, and the airframe structure between the two shapes is designed to have as much commonality as possible. Composite material is applied to the wing, tail and rear fuselage skins. In the future, we plan to expand the application of composite materials and apply composite materials to major structures.

Through the Prior Art Research Test (TRP: Technology Readiness Program), the AFP (Automated Fiber Placement) method was applied to the large composite skin to fabricate and assemble the composite structure, and the manufacturing method of the hybrid (composite + metal) structure was verified. Design, analysis, manufacturing, and testing of the main wing box to which a hybrid structure with relatively high technical risk is applied was performed in advance. The appropriateness of the analysis method of the wing-fuselage integral design concept was confirmed by the thermal load data and structural static tests due to the difference in thermal expansion caused by the The prior art research test was conducted from June 2016 to June 2018, and the reliability of structural development was increased by reviewing and supplementing design concepts in advance during detailed design and prototype production.



Most of the composite parts developed in Korea have been developed using the pre-preg-based autoclave process, and the composite skin of KF-21 also uses the autoclave process for molding the composite. However, due to the high process cost, research/development of aircraft parts using the OOA (Out of Autoclave) process, which has a relatively low process cost, is being conducted. We are developing low-cost, high-performance composite parts manufacturing technology to manufacture aircraft landing gear doors using

It is being developed to reduce inspection time and operating cost by applying a damage detection and visualization technology that can easily identify the size and location of damage within the structure by installing a sensor inside the composite/metal structure. Various cutting-edge technologies that can improve the maintainability and availability of fighters are also being developed, such as deriving aircraft preventive maintenance items and intervals through cycle analysis software.



Befitting the latest 4.5th generation fighter, sensor fusion technology was applied to display various sensors including AESA radar and information shared through AESA radar, IRST, EOTGP, and data link. It performs JDL Level 1 level data fusion, and a technique to improve battlefield situation awareness is applied by composing a single target based on target information received from each sensor through data association and estimation techniques.

The IRST mounted on the upper right of the front fuselage is being developed based on the HW of Leonardo's Skyward IRST, and the localization rate is 37%. Detection performance is improved by applying a dual-band infrared detector that detects mid-infrared (MWIR) and far-infrared (LWIR) simultaneously It has a function that assists the mod. In EOTGP, a SXGA (1280 × 1024) class cooling infrared detector that detects the MWIR band is applied, the pixel size is 15㎛, and the sensing material is InSb (Indium Antimonide). The localization rate is 82%. EOTGP is also used in air-to-air missions, and IRST and sensor fusion allow for more effective enemy detection.


Radar semiconductor transceiver application research (`06~`09)
The Defense Science Research Institute, together with LIG Nex1, developed a semiconductor transmit/receive module composed of an X-Band GaAs MMIC (Monolithic Microwave Integrated Circuit), and developed a miniature AESA antenna to which it was applied and tested its performance. The T/R module was measured to be over 10W within 10% of the bandwidth within the X-Band, and the weight was 35g. The sending/receiving unit module is a plank type and consists of 16 T/R modules. A beam steerer, a power supply, and an RF splitter are applied to each transceiver module to control the size/phase of the TR module. The radiation device is designed to enable the selective use of double polarization by composing a dual slot feeding microstrip circular patch antenna and a polarization switch.



Prior research on AESA radar for LIG Nex1 aircraft (`09~`10)
LIG Nex1 conducted prior research on the technology required for AESA radar for fighters based on the technology acquired in the research on the application of semiconductor transceiver for radar. 536 GaAs T/R modules with output 10W were designed to be arranged, but only 19% of them were mounted and a basic beam steering test was performed. The weight of the T/R module is 15g per channel, and the unit module assembly is designed as a plank type. The radiation device implements a wideband characteristic by using a Vivaldi shape, which is a tapered slot structure.


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Prior research on AESA radar for LIG Nex1 aircraft (`09~`10)
LIG Nex1 conducted prior research on the technology required for AESA radar for fighters based on the technology acquired in the research on the application of semiconductor transceiver for radar. 536 GaAs T/R modules with output 10W were designed to be arranged, but only 19% of them were mounted and a basic beam steering test was performed. The weight of the T/R module is 15g per channel, and the unit module assembly is designed as a plank type. The radiation device implements a wideband characteristic by using a Vivaldi shape, which is a tapered slot structure.


Aircraft-mounted multi-mode AESA radar application research (`10~`13)
The Defense Science Research Institute has developed a prototype of multimode AESA radar for aircraft with LIG Nex1, which has participated as a prototype development company since 2010. The prototype radar developed as an application research project for 'Aircraft mounted active phased array radar technology' consists of 504 2-channel GaN T/R modules with an output of 10W and 1,032 radiation elements. The weight of the T/R module is 10g per channel, and the unit module assembly is designed as a plank type. The azimuth/elevation beam steerable area is ±60°. Ground tests for some air-to-air modes were performed, and the Defense Science Research Institute secured radar system integration technology, hardware technology, radar signal processing software technology, and radar resource management software technology through this applied study.





Aircraft-mounted multi-mode AESA radar: test development-I (`14~`19)
Fighter-mounted multi-mode fire control AESA radar: test development-II (`17~`21)
After carrying out the applied research, the Defense Science Research Institute is carrying out the task of developing the HW and SW of the radar that can be operated in the fighter-mounted environment. LIG Nex1 is participating as a prototype development company, and SAAB is participating as a technology cooperation company. In Test Development-I, radar OFP (Operational Flight Program), radar system design / integration technology that meets the fighter operating environment, and some air-to-air modes (AAST, NAST, ACM, CST, RA, HPTT) and air-to-ground modes (RBGM, DBS) In the Test Development-II task, based on the radar HW developed in Test Development-I, air-to-air NCTR mode, air-to-ground/sea mode (SAR, GMTI/T, SSS, AGR, FTT), and machine gun fire support (GUN) Mode, guided missile data link (MDL) mode, and interleaved mode are developed.

The T/R unit module assembly is a block type and is designed as a semi-tile type in which 4 4 channel T/R modules are combined, and the weight per channel is 10 g. The total number of T/R blocks is 64, and 8 out of 1024 T/R channels are allocated for side lobe blocking. In addition to the ground test, it was installed in the ramp door of the C-130H transport aircraft and the performance test was performed.

AESA Radar HW Proof System ('16~'19)
The HW demonstration system is a miniature radar developed to check the system operability of HW and the technical completeness of the AESA radar before developing the KF-X on-board prototype. It plays a role in reducing trials and errors that may occur in the future and improving technical perfection. Under the supervision of the Defense Science Research Institute, Hanwha Systems participated as a prototype development company, and ELTA supported technical cooperation and test evaluation. The 62 T/R blocks constituting the antenna part of the HW demonstration system are composed of four 4-channel T/R modules to which GaN high-power amplifiers each having an output of 13W or more are applied. have. Through the preceding R&D tasks carried out over the past 10 years, the technology necessary for the development of multi-function radar for fighters was secured, and the development was confirmed through detailed design review (CDR), and prototype production began. did.




Prototype AESA radar equipped with KF-X (`16~`26)
The radar of the KF-21, developed by the Defense Science Research Institute and Hanwha Systems, is an active phased array (AESA) method, and is a multifunctional radar composed of 1,088 T/R modules. It is mounted on the fuselage at an angle of 15 degrees to reduce RCS. The T/R module consists of 4 channels of CHA8610-99F GaN high-power amplifier MMIC from European UMS that can output more than 13W of peak power per channel in the X-Band frequency band and more than 18W of peak power per channel based on the center frequency. It has 6-bit digital phase/amplitude control function. When power is supplied from an external device at a low voltage (about 30VDC) to the semiconductor transceiver module and other control devices, EMI problems occur due to high current, so it is designed to receive a high voltage (270VDC) from the power supply.

Based on the CDR time point, the mean time between failures (MTBF) of the MFR is 660 hours. The detection range is -45˚ to +70˚ in elevation, ±70˚ in azimuth, and the detection/tracking distance is 1XX km based on RCS 1㎡. It supports air-to-air / air-to-ground simultaneous search mode, air-to-ground SAR mode, air-to-air tracking mode, LPI mode, etc. The localization rate is 89%.


The T/R block is designed in a quasi-tile structure that combines brick-type T/R modules in units of 4 and vertically combines T/R modules on a stacked T/R control board. became The T/R blocks coupled to the AESA radar have an output of more than 10W per channel, and there are a total of 68. Unlike the existing prototype radars that were designed with a plank structure that combines T/R modules into unit module assemblies, it is designed in blocks, so it has high maintainability. It has the advantage of being excellent in terms of unit cost.

The T/R block is assembled to the radiation element assembly including the cooling plate, and the intermediate cover is assembled, so that the T/R block and the intermediate cover form the T/R assembly. At the top and bottom of the radiation element assembly, side-lobe blocking assembly antennas are disposed. The rear cover has an antenna power module, a control module, and an RF driving module, and these assemblies are manufactured as standard 6U modules and mounted in a side insertion method.


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The operability was improved by configuring the radiation device as a single module type radiation device assembly rather than as an individual unit . The replacement frequency of the radiation device composed of passive devices is low, while the replacement frequency of the T/R module composed of a number of active devices is relatively frequent. The alignment of the radiation elements aligned through the proximity electric field, etc. is misaligned. To prevent this, the T/R block was designed to be fastened to the radiation device assembly, so that stable alignment could be maintained.

In order to secure high output radiation and a wide scan area, a structure that can suppress the coupling between antennas as much as possible is introduced in the radiation element assembly to suppress the grating lobe as much as possible. The azimuth/elevation angle was maximized to ±70°.


In the plank structure T/R unit module, a water cooling cooling structure is included inside, but there is no water cooling cooling structure inside the semi-tile type T/R block. Instead, the heat of the power amplifier, which generates a lot of heat, is concentrated on one contact surface of the transmit/receive block structure, and the contact surface is cooled by contacting the cooling plate through which EGW (Ethylene Glycol Water) coolant flows. Thanks to the use of a GaN device with excellent efficiency, relatively less heat is generated, so cooling at the external contact surface can provide sufficient performance.

The antenna cooling system receives the cooling fluid from the fighter's environmental control system, collects it in the plenum above the antenna cooling plate, flows down vertically along the cooling path, flows into the plenum provided below the cooling plate, and flows again along the cooling path. It is designed to flow vertically and return to the fighter's environmental control system. The conductor and the cooling plate are designed with an aluminum alloy structure and are fastened by contact between parts.





The first prototype of the AESA radar will be released in the second half of 2020, and it will be mounted on a flight test bed to conduct flight tests. From 2023, it will be mounted on the KF-21 prototype to conduct ground and flight tests. Through SW performance improvement, the number of simultaneous air-to-air targets and SAR resolution will be improved, simultaneous air-to-air/air-to-ground/air-to-sea detection/tracking functions and electronic warfare functions will be reinforced, air-to-ground ATR (Automatic Target Recognition) and air-to-sea ISAR functions, non-cooperative targets It plans to add a non-cooperative target recognition function, a wideband data link function, and a function to cancel mutual interference with the same type of radar signal.


In addition, performance improvement for radar HW is scheduled. The 16-channel small T/R block with a tile structure is 30% lighter and smaller than the semi-tile type T/R block by applying system-in-package (SIP) technology and rigid-flexible printed circuit board (Rigid-Flexible PCB) technology. , it will replace the existing T/R block.


The integrated electronic warfare system (EW Suite) is composed of RWR, ECM, and CMDS (chaff / flare launcher), and the localization rate is 77%. The built-in ECM is being developed based on the ALQ-200K electronic warfare pod. Key parts such as a wideband digital receiver that precisely measures specifications at high speed and DRFM that stores and restores/generates signals in a wideband are designed and manufactured in the form of a card with the latest technology to make them smaller and lighter, improve the output of the amplifier, and improve the antenna It has been redesigned to be able to jam a large area by widening the beam width of the

It can receive and analyze broadband RF signal information spanning C~J-Band, generate effective radiation output of 0kW for up to 00 multiple threats, and generate jamming signals for E~J-Band and perform deception/noise/complex jamming The technique can be used to identify and perturb a variety of pulsed radars, including AESA radars, pulsed Doppler radars, and continuous wave radars.


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HUD is being developed by LIG Nex1, and HMD uses ELTA's JHMCS-II. The cockpit is a glass cockpit similar to the F-35 and is equipped with a large area display (LAD) with a 20 x 8-inch low-reflection resistive touch display. It provides the pilot with the optimal response method by selectively displaying essential flight data, aircraft data and mission performance-related information required for the pilot's mission, threat information from integrated electronic warfare equipment, and target information integrated through sensor fusion.

A Custom LCD Panel with 2560 x 1024 resolution using LED backlight is applied, and it is composed of two panels with 1280 x 1024 resolution internally. From the user's point of view, it is configured to look like a single panel. CPM uses Freescale's T2080 processor, RTOS is installed, and OFP is operated. GPM provides a function to generate and output graphic symbols, and the graphic processor uses AMD Radeon E8860.



LAD has applied redundant design and health monitoring technology to improve stability. The power input is designed to receive and use two DC 28V power inputs under the operating environment where two independent power inputs generated from the left and right system generators are supplied. was designed In addition, in the event of a failure of one display computer, the other display computer was implemented to perform a task on its behalf, enabling hot standby.

IPMC (Intelligent Platform Management Controller) that detects abnormalities for health monitoring is loaded. By measuring the input voltage and current supplied to the module, the output voltage, and the board temperature, when it exceeds the preset value range, abnormality of the module is detected, and the collected information can be transmitted through the host processor or network. Based on the collected information, each module can isolate the module to prevent secondary failure and switch the master display computer according to the severity of the abnormality.




HOTAS (Hands On Throttle and Stick) multi-function cockpit and DVI (Direct Voice Input) technology that can be controlled by voice in the cockpit is applied. The mission computer adopts the Integrated Modular Avionics (IMA) structure and is designed with an open structure based on ARINC-653. Ethernet-based AFDX+ Aircraft Data Network (ADN) protocol was applied to enable high-speed data transmission of 1 Gbps, and ARINC 818 protocol of 20 Gbps was applied to quickly transmit large-capacity video data generated by mission computers. . The tactical data link terminal to be mounted was initially considered to be equipped with Link-K, but due to the development schedule, it was impossible to acquire Link-K terminals for aircraft and Link-K technical data in a timely manner. In the future, the Link-K terminal was applied for mass production.

For the secondary power system, a pneumatic auxiliary power system consisting of an auxiliary power unit (APU, Auxiliary Power Unit) and an air turbine starter (ATS) and an electric emergency power system using a thermal battery were applied. ATS is light and simple in structure, so it is most commonly used as a fighter engine starter, and the high-pressure air required to drive the ATS is supplied from the Auxiliary Power Unit (APU). APU is a 300 horsepower class gas turbine, which is being developed by Hanwha Aerospace, with a localization rate of 73%. ATS is mounted on a separate gearbox called AMAD (Airframe Mounted Accessory Drive). The AMAD is equipped with hydraulic pumps and generators that can supply the necessary hydraulic pressure and power to the engines and fighters. The engine and AMAD are connected by a PTO (Power Take-Off) shaft, and a valve (ATSFCV, ATS Flow Control Valve) is installed in front of the ATS to control the flow rate of compressed air supplied from the APU.

The General Electric (GE) F414 engine adopted as the engine of the KF-21 is an engine capable of generating a thrust of 14,028 lbs based on sea level (SLS) and International Standard Atmosphere (ISA), and 20,856 lbs when the afterburner (AB) is activated. Fuel consumption is 0.828 lbs/lbs/hr and 1.875 lbs/lbs/hr with AB operation. It is being produced under license by Hanwha Aerospace, and the localization rate is 39%. The emergency power system was not developed separately, but a new engine-to-engine start function was added to allow the engine to be restarted using a normal engine in an emergency. By implementing the 1553 mux communication function in the secondary power system controller, the system operation mode and status are displayed on the screen. made to be For the hydraulic system, weight reduction and system complexity were minimized by applying multiple main hydraulic systems and not applying an emergency hydraulic system in consideration of the engine characteristics.





In the case of existing fighters, the engine and the forced ventilation system provided in the engine-bay surrounding the engine cooled the heat generated from the turbofan engine, which is used only before takeoff, which increases weight and cost. was counted as The KF-21 is designed with a natural ventilation structure that ventilates using the low pressure generated between adjacent nozzles when the engine is operating by forming a ventilation hole between the two engine nozzles, thereby cooling the engine and preventing fire. This natural ventilation structure design is structurally simpler than the existing forced ventilation system and can save weight. Since the intensity of the low pressure generated behind the nozzle is proportional to the engine output, the higher the engine output, the higher the internal ventilation flow rate. The higher the output engine, the more natural the engine temperature can be controlled.

The KF-21's electrical system is configured to supply power to the aircraft through two 65kW generators and a power distribution system. Developed by UTC Aerospace Systems and Hanwha Machinery, it is a variable speed input - fixed frequency output (VSCF) generator equipped with an integrated package converter and control device that electronically converts variable speed output to desired frequency output. CAN (Controller Area Network) communication is applied to monitor the status and faults of each equipment, and the operation mode and status of the electrical system are displayed on the screen in connection with the avionics 1553 mux communication, enabling real-time monitoring and fault display. In addition, fiber optic cables and giga internet cables are applied to achieve high-capacity data transmission and weight reduction.


Senior member
Dec 6, 2017
Republic of Wadiya

The machine gun is the M61A2 mounted on the F-22 and F/A-18E/F. The maximum armament is about 17,000lb, and various armaments such as AIM-9X, AIM-120, SDB, CBU-105, JDAM, LJDAM, LGB, AGM-65 can be operated. In consideration of export, in addition to the US-made armament, European armaments such as the KEPD 350 Taurus, IRIS-T, and Meteor, as well as domestic armaments such as long-range air-to-ground guided missiles-II and KGGB, are also planned to be integrated. There are a total of 10 hard points, 6 at the bottom of the wing and 4 at the bottom of the fuselage. The hard point at the bottom of the fuselage is a Missile Eject Launcher (MEL) for semi-buried weapons, and it can carry four Meteor or AIM-120 AMRAAM missiles.

Reinforcement design was applied to the bulkhead to minimize aircraft modification when applying internal armament, and internal space was secured in advance by designing in consideration of internal armament and armament mount, support structure, internal armament door and opening/closing fitting, and actuator. . At the time of Block-I, a support structure for mounting semi-buried weapons and an arming platform are installed in the space. When applying the internal armament, the semi-recessed armament mount and support structure applied in Block-I is removed, the number of bullets is reduced from 6 to 4 rows, and the LRU (Linear Replacement Unit) and the wiring are rearranged.

Logistics support


KF-21's Logistics Support Analysis (LSA) system is linked with Electronic Technical Manual (IETM) and RAM (Reliability, Avaailability, Maintainability) analysis system to automatically edit technical manuals and automatically update data such as mean time between failures (MTBF) The following functions are applied, and the follow-up logistics support system (K-LIS) provides the flight, maintenance, configuration management, supply, lifespan management, education and training basic functions required for aircraft operation, and BIT (Built) of major components extracted during aircraft operation. In Test) data and FDR (Flight Data Record) data are integrated and managed as a big data-based integrated information system.

Production process and prototype



With the introduction of Hantmann 5-axis high-speed machining equipment for KF-21, all the old parts processing equipment, which had chronic problems, was replaced with new equipment, and the 600-ton skin stretch equipment was introduced to secure the productivity of large sheet metal equipment. At the same time, Form Cam Software was introduced to secure a stable production base that dramatically reduced the defect rate through molding simulation before input. By introducing AFP (Automated Fiber Placement), large autoclave, CRD (Composite Routing Drill), and UT C-Scan equipment for the production of large composite parts such as main wing and central fuselage skin, the inspection ability is 6 times higher than before. FASS (Fuselage Automated Splice System), an automated assembly equipment that aligns airframe structures with an error within ±0.001 inch (0.025mm), AGV (Automated Guided Vehicle) carrying the fuselage, hole processing and countersink AR (Auto Riveter) and LRDS (Large Robot Drilling System) used for fastening of back were applied to improve work efficiency. In particular, AR and LRDS reduced work time by more than 84% compared to manual work, and FASS reduced work time from 11 days to 2.5 days, contributing to the improvement of KF-21's productivity.



Starting with the first part processing in February 2019, after the detailed design review (CDR) was completed on September 26, 2019, the full-scale prototype production work began, and on September 3, 2020, the front, center, rear fuselage and main wing of Prototype No. 1 · Entered the final assembly process to connect the tail. A total of 8 prototypes will be manufactured, including 1 prototype for static structural testing, 1 prototype for durability structural testing, 4 single-seat prototypes for flight testing (Units 1 to 3, 5), and 2 two-seat prototypes (Units 4 and 6). Produced and tested for ground and flight tests.




On April 9, 2021, the delivery ceremony for the first prototype was held at the KAI Sacheon plant. The ceremony was attended by key officials from the government and military, Indonesian government delegation including Indonesian Defense Minister Prabowo Subianto, officials from defense companies such as Korea Aerospace Industries, and people from all walks of life. It was named the KF-21 with the meaning of being a domestic fighter that will protect the Korean Peninsula in the 21st century, a pivotal force for leaping into the aerospace force, and was nicknamed the Boramae, which was submitted by the most number of people through a contest.
performance improvement

Block-I : This aircraft will be electrified for the first mass production (1st) in '26~'28, and can perform air-to-air missions and limited air-to-ground missions. The mass production quantity is 40 units.
Block-II : Armaments that can be operated are added through the residual armament test conducted between '26 and '28. In '28~'32, 80 units are expected to be electrified through follow-up mass production (secondary). Sheet-type RAM, RAS, canopy ITO coating technology, automatic terrain tracking and ground collision avoidance system, which were excluded from the first mass production, will be applied.


Senior member
Dec 6, 2017
Republic of Wadiya



Successor to KF-X (Block-III) : The successor to KF-X, scheduled to launch after the 2030s, will include RF/IR complex stealth technology, microwave scattering control metasurface technology, AESA radar performance improvement, buried EOTS, wing built-in ultra-wideband AESA antenna and next-generation Various new technologies that can improve mission performance on the battlefield in the future are expected to be applied, such as electronic warfare systems, next-generation survival systems such as DIRCM, 250kw class high-power density starter/generator, and unmanned aerial vehicle remote air control system for unmanned and unmanned cooperative missions. In the case of internal armaments that are mainly discussed, a combination of 4 AIM-120, 2 AIM-120 & 4 GBU-39, and 8 GBU-39 is possible. Next-generation weapon systems such as air-to-air missiles, mid-range air-to-air missiles, and air-to-ship guided missiles-II are expected to be integrated.



Senior member
Dec 6, 2017
Republic of Wadiya

KF-X single seat / double seat​



Source: KAI webzine Fly Together August issue


KF-X C109 정리(18.07.13 수정)​



UAV development and commercialization for search and reconnaissance around artillery bases/main facilities​


2018. 7. 26. 17:29

Combat in a military mission environment using the results of the "UAV for search and reconnaissance around artillery positions/main facilities" project (hereinafter referred to as "existing task") conducted as a civil-military technology application study from July 2016 to January 2017 It is a civilian-military technology practicalization-related project that evaluates military applicability through experiments. It is a practical interlocking task that conducts combat tests of electric propulsion multicopter-type small drone system and operation technology that can take off and land vertically according to military needs and has excellent flight stability. plan to be applied.
- Drone technology for monitoring/reconnaissance for artillery positions and air units, etc.
- Technology to observe the impact point and coordinate correction of artillery battalion shells
Importance/necessity of small multicopter-type drone operation technology for small units/special warfare units, etc. The enemy that threatens the most surveillance of the artillery camp reconnaissance system deployment needs - Extended endurance specify the target automatically or manually track moving targets automatically track , the position of close combat enemy mechanized units of the region, starting and orientation through real-time monitoring of thermal induced demands , the main target When operating Korean artillery firepower, it is necessary to observe the impact point, correct the coordinates, and provide strike information in real time - Overcoming the blind spots of monitoring assets for damage assessment, and replacing human information assets with many temporal and spatial limitations (survivability, mobility, etc.) Technology development the urgency of

Prior to the deployment of the Army's 'Drone Bot Combat System' to full power, it is necessary to conduct a rapid commercialization linkage project through an assessment of the suitability of military requirements for drones developed as a civilian-military project (combat experiment). Promoting the early deployment of drones to meet military requirements.
Period and Research Fund · Period: within 2 years. (Proposal organizations are requested to propose a development schedule as short as possible.) - Provision of a prototype for the 1st battle experiment (5set): Suggestion of the provision schedule - Provision of a prototype for the 2nd battle experiment (5set): Suggestion of the delivery schedule Suggestion organization - Evaluation of an accredited certification test and environmental test · Government contribution out of total research expenses: less than 700 million won This is a civil/military technology commercialization related project.

What kind of fighter is the KF-X?​


2018. 7. 16. 15:23
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Text Other Features


Korean-style fighters replace the outdated F-4/F-5 fighters of the Air Force after the 2020s, ensure a selective response to unspecified threats in the future, and secure air superiority within the defense sphere of the Korean Peninsula for long-range precision strikes and land and sea infiltration forces It is a multi-role fighter with the ability to neutralize In other words, the development goal of the Korean fighter is to satisfy the military structure and to be operationally efficient, to operate Network Centric Warfare (NCW), and, above all, to be able to equip domestic armaments to demonstrate the best operational capability. It is not the most advanced fighter, but it is a high-performance, high-precision, and high-efficiency multi-purpose fighter.

Modern fighters can maintain their power by constantly improving their performance from deployment to disposal due to the rapid development of avionics and precision-guided weapons. Therefore, it aims to develop core equipment and software such as computers and sensors for core fields such as avionics, armament control, survival system, and flight control system to enable independent performance improvement and installation of domestically developed guided weapons. do.

The Korean-style fighter is KF-16+ in terms of armament operation capability, combat radius, and flight performance, and its electronic warfare capability, avionics and sensor (radar, target detection equipment, etc.) capabilities are superior to the KF-16. do. In particular, it responds to the development trend of fighters in neighboring countries and applies limited stealth technology to improve survivability.

Source: A study on ways to secure key technologies for the development of Korean-style fighters (Korea Military Science and Technology Association 2010 Comprehensive Conference)

I found and read the thesis and brought it because it explained well what kind of fighter the KF-X was developed. In the meantime, many people have vaguely explained that the KF-X is a medium-class fighter and KF-16+-class performance. I would like to talk about KF-X