Notes:

As allies of Australia, the new Korean aircraft, KF-21, is an important consideration, as it will likely be part of allied integration programs in the region.

DEVELOPMENT

For the past number of decades, the South Korean military has attempted to increase its ability to produce equipment domestically. Just as with its neighbour Japan, South Korea has a promising aerospace industry, yet for a variety of reasons, still primarily relies on other western nations to provide aircraft and armament. However, in recent decades, Korea has made several moves to produce its own aircraft.

Beginning in 1992, Korea Aerospace Industries began development on what would become known as the T-50; a supersonic jet trainer which could double as a combat aircraft if necessary. This aircraft – a fleet of which now exist – served as a proof-of-concept for what would become known as the Boramae – or hawk – a new project seeking to develop a replacement for the ageing fleet of F4 Phantoms and F5 Tigers still in service.

First announced in 2001, the project was initially met with some scepticism, which was understandable. Korea was setting out – with only one training jet under their belt – to not only produce a fighter from scratch, but one that could rival the best American, Russian, and European designs; all of which have long histories designing and perfecting aircraft. It would also cost more per unit than purchasing foreign aircraft, due to the added cost of building the production line.

For many years the project was unable to garner serious interest. However, in 2010, this would change. Increasing pressure from North Korea led to a renewed national interest in the project. Indonesia would jump on board, promising to handle 20% of the funding, and interest was also shown by Turkey. Other investors would fund a further 20%. The remaining 60% of the cost would be paid for by the South Korean government, who were now convinced of a desirable outcome. Winning the bid would be the tried and tested Korea Aerospace Industries, who chose to partner with Lockheed Martin for support. Thus, the project got underway.

Three initial proposals were developed and submitted; the first – code named C103 – resembled an F-35, whilst the second – C203 – resembled a European delta wing design with forward canards. The third design – C503 – would be a single engine, low-cost fighter. The Air Force chose the first – C103 – noting that two engines would be preferable over lower costs.

In 2015, development of this concept began, and over the next two years wind tunnel testing would be used to improve the initial proposal. This resulted in a further four variations on the initial C-103 design, each with varying capabilities; C-104, C-105, C-107, and C-109. Of them, design C-105 (now named KF-X) would be chosen as the design to carry forward. According to Korean sources, C-105, lacked an internal weapons bay, it was the smallest of the designs, and initially it had only one engine. At the end of the day, it appears that the desired elements of the other designs were integrated into the C-105.

Nearly 11 years after the start of the program, on July 12, 2021, the first prototype was ready. Named ‘KF-21’, the aircraft attracted international attention. Notably, Poland, Peru, and the Philippines, all expressed interest in the aircraft. Following this, work began on a further eight aircraft: two ground test units, two twin seat flight units, and four single seat flight units. In July 2022, the first of these single seat flying units made its maiden flight. This would be followed up in November 2022 by a second aircraft, and in January 2023 by a third, which would also complete the first supersonic flight. In February 2023, the first two-seater aircraft would take flight.

According to Korea Aerospace Industries, the current plan is to equip the Air Force with a fleet of 40 KF-21s by 2028, have a full fleet of 120 by the year 2032. These will be the initial ‘Block 1’ configuration, limited to air-to-air capabilities. Once this first phase is completed, the plan is to then begin a ‘Block 2’ development program, which will roll out full air-to-ground capabilities.

Why this unusual decision to launch without multirole capabilities is unclear. If a guess had to be made, it is possible that the aim is to push the aircraft into service as quickly as possible while dealing with the more time-consuming technology in a second phase. It has also been noted by the designers that – if Korea ever acquires aircraft carriers – a modified carrier version of the aircraft designated KF-21N, could be produced within just a few short years. Indonesia – who has also been a partner in this venture – may purchase a further 50 of these aircraft for her own fleet.

The future multirole nature of the aircraft has been highlighted since the initial flight tests. Ordnance will include such ground weapons as GBU-12 Paveway 2s, various JDAMs, and CBU-105s – a modified version of the American CBU97 cluster bomb, to name a few. Air-to-ground missiles have also been alluded to integration, namely the anti-ship AGM-84, and the AGM-65 maverick.

In terms of air-to-air weaponry, the aircraft should be capable of carrying standard American weapons – namely the AIM-120 AMRAAM for BVR – and the AIM-9X for close range, along with plans to integrate the ASRAAM – a supposed sidewinder replacement.

However, the loadout of choice for the aircraft appears to be a combination of the Meteor active radar missile for long range, and the IRIS-T infrared for close range. MBDA – the European company behind the Meteor – announced that they had been working with Korea Aerospace Industries to integrate the missile into the KF-21 platform. This choice is rather interesting, as for many years, the tried and tested AMRAAM was considered the most reliable active radar missile available, however since its initial testing, the Meteor possibly outperforms the American design.

South Korea also plans to integrate its fleet with air-launched cruise missiles, or ALCMs. This was confirmed by South Korea’s Defence Acquisitions Program Administration (DAPA), with the system development phase coming into effect on December 12, 2023, and a slated completion date of 2028.

These designs (named Sky Dragon) have already been test-launched from Korean F-4Es, and it has been insinuated that such a missile would have a range of 500 kilometres. The South Koreans are not only focused on close-air-support, but also precision strike capability, given a 500-kilometre range of the most important North Korean infrastructure from the South’s norther boarder. North Korea lacks a modernised Air Force, but it does have one of the largest standing armies in the world, with heavily fortified command and control infrastructure. A 500-kilometre range ALCM, could be launched from an aircraft without encroaching North Korean airspace. Although we don’t know the details, it is likely that the ALCM program will have bunker busting capability. This is implicit when suggestions have been made that the ALCM may replace the existing KEPD 350K cruise missiles, (a system said to be to penetrate up to 20 feet of concrete).

These programs fall under Korea’s ‘three-axis operational plan’, which seeks to prevent any nuclear threat from the north. This includes surprise first strikes on nuclear weapons positions, followed by the interception of any cruise missiles. The third axis, known as ‘overwhelming response’, would serve as a retaliatory strike campaign if the north made the first move, with primary targets being command and control structures and launch sites. The KF-21 and cruise missile program are integral to the development of this plan.

PERFORMANCE

So what about the performance and real world capabilities of the aircraft? These are early days, anything is possible, although some inferences can be made. Firstly, it has been suggested that the priority of the KF-21 is not stealth – as with the F-35 and F-22 – but rather a balance between reduced radar cross section and maximum weapons payload. This has been made obvious in the choice to mount weapons externally, rather than internally as in other fifth-gen stealth aircraft. With four hard points on the fuselage, and six on the wings, this could suggest a similar radar cross section to the Typhoon. In fact, during development, one of the projects goals was to produce an aircraft capable of outperforming both the Dassault Rafale, and the Typhoon, and the aircraft has been referred to as a 4.5-gen, not 5th-gen, design.

One of the more popular commentaries – and one which appears to be in line with the goals of the South Korean Air Force – is that the KF-21 will serve as an intermediary between the stealthier F-35, and the cheaper F-16. Sitting in the middle, the KF-21 could carry more weaponry than the F-35 with an internal load but retain a smaller radar image than the F-16. This could prove beneficial in joint missions, in which the strengths of each aircraft are utilised – stealth from the F-35, speed and dogfighting ability from the F-16, and a steady middle ground from the KF-21. During production it was stated that the aircraft should outperform the F-16 in several areas: namely, 50% greater combat range, a better AESA radar and datalink, and a 30% longer lifespan.

Powering the aircraft is the General Electric F414. Currently in use on the Super Hornet and newer variants of the Jas 39 Gripen, the engine strikes a good middle ground; powerful, whilst also reducing fuel burn rate and maintenance time. With the GE-400K variant of this power plant, current information suggests that the KF-21 will be able to reach 1200 knots, or Mach 1.8, with a combat range of up to 1000 kilometres. This is substantially better than the F-16s 500-kilometre combat range. This is likely due to the nearly 14-thousand pounds of internal fuel in the KF-21, compared to the 7-thousand pound internal capacity on a clean F-16. In terms of armament, the KF-21 can carry seven thousand seven hundred kilograms of stores. This happens to be the exact amount that the F-16 is rated to carry.

The aircraft also comes equipped with an electronic warfare suite – which will be further enhanced in the two seater version – along with AESA radar, infrared search and track, and an electro-optical targeting system.

 

SIMILAR DESIGNS

So, what will the aircraft be competing against on the global stage? The KF-21 is just one of an increasing number of fifth generation fighter designs to be unveiled in recent years. Within the region, Japan and China both have similar fifth gen aircraft, the specifics of which remain under wraps. The most internationally prominent of these is the Chengdu J-20, a Chinese design which entered service in 2017, but largely remains a mystery in terms of its capabilities. This was followed by the Shenang FC-31, an aircraft appearing to draw inspiration from fifth gen Lockheed Martin designs. The FC-31 first flew in 2012, and remains a prototype design, although it will likely enter service with the Peoples Liberation Army Navy as a carrier-based aircraft. Of the two Chinese aircraft, it is likely that the FC-31 will prove a bigger threat, as the Shenyang Aircraft corporation is known to develop particularly good aircraft – notably the J-16, which has been claimed by multiple sources to be superior to any Sukhoi derivative in development.

Similar to the FC-31 is Mitsubishi’s X-2, designed in Japan. This prototype design – again appearing to be inspired by Lockheed’s fifth gen aircraft – currently exists as the foundation for a sixth-generation fighter aircraft – codenamed Mitsubishi F-X. As with the FC-31, it would be naive to suggest that the Japanese F-X program is a paper tiger. Mitsubishi has earned a reputation for producing aircraft with reliable consistency – from the A6M Zero in World War 2 to the F-2. The F-2 – derived from the F-16 Viper – supposedly outperforms the original design in multiple areas.

Beyond Asia, other notable fifth gen designs include the Indian HAL AMCA, the Turkish TAI TF Kaan, and the Russian Sukhoi 75 Checkmate.

The Indian HAL AMCA is likely the most comparable to the KF-21. With plans to outfit the aircraft with similar weapons, the AMCA will also likely fly on the same General Electric F414 engines. Given India’s geopolitical position, this aircraft would need to be capable of integrating with both western and Russian aircraft.

The Turkish design – the TAI TF Kaan – was first displayed on March 16th 2023, although it has not yet taken to the sky and nothing can be confirmed about the aircraft or its capabilities. However, what appears to set the Turkish design apart from its contemporaries – perhaps due to overconfidence – is its rollout plan. As of 2023, the Turkish Air Force holds that its F-16 fleet will be retired and replaced by the new aircraft, perhaps beginning as early as 2028. Given Turkey’s proximity to active combat zones, this claimed adoption plan does suggest a particularly high level of confidence in the design, especially given the exceptional combat record of the F-16.

The final design is Sukhois Checkmate, or SU-75. As with the SU-57, little information is released to the public about specifics, or progress in development. This could very well be a capable aircraft with no need for international publicity. Given the tension between east and west as of late, this design – as with the SU-57 – will likely be kept out of the spotlight and away from air shows, especially so if cutting edge.

What appears to be common amongst all these fifth gen designs is a focus – or at least an outward appearance of focus – on minimised radar visibility over maximised performance.

 

AUSTRALIA’S LESSON

Thus far, the KF-21 looks promising as a native design for the South Koreans. Even though they are launching the aircraft without full multi-role capabilities – for a smaller country this still marks the beginning of an aerospace industry capable of competing at the highest international level.

The development of this aircraft serves as a lesson that small nations – (not the least of which being Australia) – can and should produce original aircraft domestically. During the second world war – under threat of Japanese invasion – Australia did indeed prove itself capable of developing its own aircraft. The current turbulent geopolitical environment should prompt policymakers toward sustainable domestic capabilities in terms of aircraft and ordnance production. It is easy to imagine the Australian continent isolated from allied supply lines. It has the resources to produce great, original military equipment, which would help secure the nation, bolster Australian industries, and open many more employment opportunities.  One can only hope that the South Korean KF-21 program might inspire Canberra along these lines.