Seoul Plans Phased-Development, Typhoon-Size Fighter

By Bradley Perrett
Source: Aviation Week & Space Technology

Also relying on airframe volume, the designers are contriving to work a weapons bay into the Block 2 version. In the Block 1 variant, four Raytheon AIM-120 air-to-air missiles are mounted in recesses under the fuselage, a favorite approach introduced by the Phantom's designers about 60 years ago (see cover photo). Those missiles must move inside the bay for the Block 2 KF-X; there is not enough space to have both a bay and external under-fuselage weapons. Provision for the weapon bay will be in the Block 1 aircraft, ADD says, which must mean that internal equipment will be packaged in some way to easily make space available.

Six more hard points for weapons and other stores are on the wing, the outer two available only for Raytheon AIM-9X short-range air-to-air missiles. ADD's drawings show the others with air-to-ground weapons: GBU-39, GBU-53, CBU-105, GBU-31, GBU-38 and GBU-24 guided bombs and AGM-65 missiles. External fuel tanks are an option for the inner pair of hard points, and models show cruise missiles mounted in those positions, too. There are no wingtip hard points, presumably to restrict radar reflections, but models show sensor pods on the lower corners of the fuselage.

A gun is mounted internally above the left inlet duct.

The prime sensor for KF-X will be a radar with an active, electronically scanned array. A foreign radar will be installed first, while a later version of the fighter will be outfitted with a set based on work that South Korean electronics company LIG Nex1 is undertaking. The designers are also specifying an electro-optical targeting system, an infrared search and track sensor, data link, GPS-INS navigation, “advanced threat warning and countermeasures” and internal electronic countermeasures.

The cockpit will incorporate a helmet-mounted display, a head-up display and multifunction head-down displays. In integrating electronics and weapons, the program intends to follow Western design standards, hence the advantage that KF-X, if built, will hold over Chinese and Russian rivals. Introducing new U.S., European or indeed South Korean equipment should be easier.

The wing of the C103 (tail-aft) version has full-span flaperons and leading-edge flaps for variable camber. The planform is a diamond shape, with 40 deg. leading-edge sweep and 10-deg. forward sweep for the trailing edge.

When the C103 and C203 designs were discussed in February, there was a hint that the two-seat option had been rejected, along with such variants as a single-engine aircraft. But ADD's latest description of the aircraft does show a version with a second seat that replaces the forward fuselage fuel tank. Although the U.S. has decided that simulation obviates the need for a trainer version of the F-35, a second seat is becoming popular again in other fighters for a reason that was familiar decades ago but then fell out of fashion: two people can handle the work of a combat mission more easily than one.

Tap the icon in the digital edition of AW&ST to see a timeline of KF-X program, or go to

KF-X Specifications
KF-X C103 (aft tail)KF-X C203 (canard)Eurofighter Typhoon
Length15.7 meters51.3 ft.15.8 meters51.9 ft.15.9 meters52.3 ft
Height4.5 meters14.9 ft.4.2 meters13.8 ft.5.3 meters17.3 ft.
Wing area42.7 sq. meters460 sq. ft.51.8 sq. meters558 sq. ft.51.2 sq. meters551 sq. ft.
Aspect ratio2.72.152.34
Leading edge sweep40 deg.54 deg.52 deg.
Dry thrust (x 2)> 12,000 lb.> 12,000 lb.13,500 lb.
Afterburning thrust (x 2)> 18,000 lb.> 18,000 lb.20,000 lb.
Empty weight10.9 tons24,000 lb.11.3 tons25,000 lb.11.2 tons24,600 lb.
Internal fuel5.4 tons12,000 lb.5.9 tons13,000 lb.5.0 tons*11,020 lb.
Maximum weight24.0 tons53,000 lb.24.9 tons55,000 lb.23.5 tons51,800 lb.
Sources: Agency for Defense Development and Eurofighter, except * industry source.

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