Many of the headlines accompanying the rollout of South Korea’s new 4.5th generation KF-21 Boramae (Hawk) fighter last week trumpeted it as a cheaper alternative to the F-35. While it may not have the full stealth and network capabilities of the Lightning, it represents a capable and expensive investment in South Korean independence and regional options outside of China’s sphere.

South Korean president, Moon Jae-in, said as much during last Friday’s rollout ceremony, asserting that “a new era of independent defense has begun, and it’s a historic milestone in the development of the [South Korean] aviation industry.”

The ramp-up of the program symbolically elevates South Korea to a historic club. A government release cited by CNN noted that South Korea will become the eighth country in the world that has developed an advanced supersonic fighter.

There are obvious American fingerprints in the KF-21’s design and components (engines for example) but about 65% of the fighter is actually of South Korean origin. With its first flight, slated for 2022, the Hawk will make Seoul an upper-tier player in the international tactical aviation market.

Before the rollout, South Korean spokesperson Lim Se-eun notably remarked that the country has set a goal to become the world’s seventh-biggest aviation industrial power by the 2030s.

Regional potential for the new fighter is signaled by Indonesia’s cooperation in the $7.9 billion project as a minority (20%) partner. Several years of late payments for its share of the program notwithstanding, Indonesia remains onboard and Jakarta’s defense minister, Prabowo Subianto, attended the rollout last Friday.


Indonesian plans call for acquiring 50 KF-21s with a mix of the air defense and strike variants that Korea Aerospace Industries (KAI) is developing. Indonesia is interested in receiving technology-transfer from its participation but its motivation lies squarely in common concerns about China’s burgeoning influence and territorial claims in the East and South China seas.

In late March, Indonesia signed an agreement with Japan opening the way to Japanese defense exports to the Indonesian armed forces. The first of these may be a deal for up to eight of Japan’s new Mogami-class stealth frigates. Indonesia is experiencing frictions in waters around the Natuna islands, some of which lie inside Beijing’s controversial regional maritime claims. The multi-role frigates could blend well with KF-21s, sending a message to China.

The KF-21 could likewise give Southeast Asian customers like Thailand, the Philippines, and possibly even Iraq, an alternative to 4th generation European and Russian aircraft with the added benefit of design and operational features with which they’re familiar. Asia-Pacific military analyst, Abraham Ait, noted that the above nations operate the South Korean FA-50 light attack fighter and either the F-16 or the F-5 which the KF-21 was designed to replace.

F-35-Like With Fewer Strings

The Boramae is poised to send a strong message to the region and China in particular regarding the autonomy of its peninsular neighbor. Teal Group analyst, Richard Aboulafia points out that with it South Korea may have one of the most flexible, relevant fighter products on the global market.

“It’s a Generation 4.5 plane that will allow South Korea a prestigious defense program and a greater degree of weapons autonomy, if not sovereignty. It’s expensive, but given their priorities it’s perhaps inevitable,” Aboulafia observes.

“And besides, with the USAF now saying that Generation 4.5 might need to be a viable procurement track, the ROKAF [Republic of Korea Air Force] might not be the only service with a new plane in this class.”

South Korea’s air force expects the KF-21 to replace its aging F-5E/F Tiger IIs and F-4 Phantoms as well as some older F-16C/Ds and F-15K Slam Eagles. It’s also viewed as a highly effective complement the 60 F-35As that South Korea is buying from the U.S.

Approximately 40 KF-21s are expected to be in ROKAF service by 2028, all likely Block I air defense versions of the Boramae. The first prototype shown at the rollout will be joined by three more single and two twin seat airplanes to fill out the test program. Development is ambitiously brief, crammed into a 4-5 year period before the first KF-21 deliveries begin in 2026.

Though it bears obvious resemblance to the F-35, the KF-21 is a twin, rather than single-engine airplane, the prototypes powered by a pair of General Electric F414-GE-400K engines. GE will supply 240 F414s for the the full fleet of 120 aircraft planned to be in service by 2032.

Commonality with F414 variants found in the F/A-18 Super Hornet and JAS 39E/F Gripen among others helps KAI skip dedicated engine development and ensures a solid supply chain. KAI also has previous experience integrating GE’s F404 engine in its T-50/FA-50 aircraft. The thrust available should, along with the airframe, give the KF-21 aerodynamic performance in excess of the F-16C.

Like the F-35 and F-22, the Boramae will offer stealth though not to the same degree as the American 5th generation fighters. According to the The WarZone, the KF-21 is thought to have a radar cross section on par with the Eurofighter Typhoon but planned upgrades should reduce its radar signature considerably.

All-aspect stealth is blunted by the choice to carry the KF-21’s weapons externally on six under-wing and four under-fuselage hardpoints. The sacrifice in detectability is offset by the lower cost and likely shorter development made possible by forgoing an internal weapons bay.

KAI affirms that weapons for the strike variant are all currently in the ROKAF inventory including Paveway II laser guided bombs, GPS/INS-guided GBU-39 Small Diameter Bombs and GBU-31/38 Joint Direct Attack Munition bombs, plus CBU‐105 Wind Corrected Munitions Dispenser kits.

The company figures for a payload up to 16,975 pounds, a top speed of around 1,400 miles per hour (Mach 1.83) and a range of approximately 1,800 miles put the KF-21 ahead of the F-35A in terms of performance attributes. An indigenously produced (by Hanwha Systems) active electronically scanned array (AESA) radar can be teamed with long-range weapons like MBDA’s Meteor air-to-air missile, extending air defense reach beyond that of the ROKAF’s F-16s.

The combination yields an F-35-like deterrent, augmented by the country’s own fleet of Joint Strike Fighters and the ROKAF’s own Boeing E-737 Peace Eye airborne early warning and control aircraft.

While not a full-fledged 5th generation fighter, the KF-21 should beat such aircraft from the UK, Europe, Japan. India, and Turkey to market. It’s sticker price will be less than these and its early availability will be bolstered by another, often overlooked, factor.

The Boramae won’t come with the strings attached either to the F-35A or to China’s J-10CE fighter.

The former requires buyers to closely integrate into the Joint Strike Fighter ecosystem and (with the exception of the Israelis) stick to avionics and software updates chosen and controlled by Lockheed Martin LMT and the U.S. government. The latter comes with potentially low upfront cost but also with amply demonstrated and heavy-handed China influence operations. The baggage of Chinese/Russian fighter engine unreliability is a big sticking point as well.

With KAI developing the KF-21’s critical avionics (mission and flight-control computers) and associated sensors, foreign buyers might expect less interference and a better product with more certain supply.