KF-23 Chammae

KF-23 Chammae
	KF-23 Chammae flies over Naju city.
Role	Stealth aircraft; Air superiority fighter
National origin	Joseon
Manufacturer	Korea Aerospace Industries, Ltd.
First flight	7 June 2018
Introduction	15 December 2020
Status	In service
Primary user	Royal Joseon Air Force; Royal Joseon Navy
Produced	2018-Present

The Korea Aerospace Industries(KAI) KF-23 Chammae is a Joseon's twin-engine, all-weather, supersonic stealth fighter aircraft developed and produced for the Royal Joseon Air Force(RJAF). The KF-23 Chammae was designed as an air superiority fighter, but also incorporates ground attack, electronic warfare, and signals intelligence capabilities. The manufacturer, KAI, was responsible for all but the engines, including the airframe, weapon systems, and the final assembly of the aircraft. Hanwha Aerospace was responsible for the aircraft's engine manufacturing and installation.

The KF-23 is a critical component of the RJAF's high-end tactical airpower. the aircraft became the service's leading platform for air-to-air missions against peer adversaries. Like all other combat equipment and vehicles in the Royal Joseon Armed Forces, the KF-23 is also integrated into the Joseon's Battle Management System(BMS), 'Gongmyeong-2E,' sharing real-time information about battlefields and changes in conditions with other units and aircraft, vehicles, and ships.

Development

KF-23 originated from the HETF(High-End Tactical Fighter) program, which was launched to replace the KF-19 Songgolmae, and supplement KF-21 Boramae and KF-20 Chamsuri, which served as transitional fighter jets. The HETF program was a project to develop new tactical aircraft that can seamlessly perform missions even in extreme battlefield conditions, with the viability of existing 4th and 4.5th generation fighters in doubt due to changes in battlefield environments and advances in anti-aircraft weapons. RJAF launched the HETF project in 2012, but it actually took two more years for the project to be implemented after budgeting. The project was led by the Agency for Defense Development(ADD) and KAI.

The Air Force wanted to acquire fighter jets with electronic warfare capabilities and performance that overwhelmed all tactical aircraft of neighboring countries through the outcome of the HETF project. The Navy wanted to add the capability of taking off and landing on the CATOBAR aircraft carrier in addition to the required performance of the Air Force. In addition, both the Air Force and the Navy demanded that the HETF project's result have counter-stealth capabilities to counteract enemy stealth fighters.

The first prototype aircraft of the KF-23 flew in 2018. 6 more prototype aircraft were built after the flight of the first prototype aircraft, and the entire test flight process ended in 2020.

Design

Avionics

The KF-23 is equipped with AN/APG-02 AESA radar. This radar can operate up to 10 channels at the same time with very precise signal tracking, so it can accurately track RF (Radio Frequency) signal sources. In addition, AN/APG-02 tracks RF radiation sources very precisely through the process of phase-matching all signals detected in the channel where signal tracking takes place. These manual tracking capabilities are very useful for identifying/tracking target signals in EW and can demonstrate very innovative stealth tactics that send and receive signals from the signal emission platform and ECM at a distance greater than the hostile radar can detect KF-23.

AN/APG-02 is highly resistant to DRFM jammer attacks due to enhanced electronic protection capabilities, can organically change frequencies or patterns of radio waves, and radio algorithms are also very complex, reducing the risk of exposure to locations through radio backtracking by enemy ESM equipment or Passive radar. The AN/APG-02 radar can also detect smaller targets, such as inbound missiles and can track air targets beyond the range of the aircraft's air-to-air missiles.

Also, AN/APG-02 boasts such a large detection range that it can detect an object 1 m^2 in size at 380 km. This exceeds the KF-19's maximum detection range of 185 kilometers. However, the true capability of AN/APG-02 exists in electronic warfare capabilities, not detection distances, and the active scanning radar AN/APG-02 uses 1,500 semiconductor microwave modules (T/W) with a maximum output of 8 watts and a weight of 20g to fire radar beams of different wavelengths. Launching radar beams of these different wavelengths makes it difficult for the enemy fighter's Radar Homing And Warning Receiver (RWR) to detect KF-23's radar operation, and KF-23 can Lock-on the enemy without the enemy knowing it.

In addition to the AN/APG-02 AESA radar, the KF-23 is equipped with L-band radar on both main wings and tail wings to detect enemy stealth aircraft and is used in conjunction with each radar. In this way, KF-23 can detect enemy stealth aircraft by operating radars in various bands.

The KF-23 Chammae's EOTS is responsible for exploring the approximate location of enemy stealth targets detected by KF-23 using L-Band and X-Band radars in more detail, identifying detailed location information of enemy stealth targets, and guiding radar-guided missiles, including AIM-120D, to enemy stealth targets. The EOTS mounted on the KF-23 has a detection range of 150 kilometers, and if necessary, the KF-23 can perform BVR(Beyond-visual-range) air combat using only EOTS without radar operation.

Stealth

The KF-23 was designed to be highly difficult to detect and track by radar, with radio waves reflected, scattered, or diffracted away from the emitter source towards specific sectors, or absorbed and attenuated. Measures to reduce RCS include airframe shaping such as alignment of edges and continuous curvature of surfaces, internal carriage of weapons, fixed-geometry serpentine inlets and curved vanes that prevent line-of-sight of the engine faces and turbines from any exterior view, use of radar-absorbent material (RAM), and attention to detail such as hinges and pilot helmets that could provide a radar return.

The KF-23 was also designed to have decreased radio frequency emissions, infrared signature and acoustic signature as well as reduced visibility to the naked eye. The aircraft's flat thrust-vectoring nozzles flatten the exhaust plume and facilitate its mixing with ambient air through shed vortices, which reduces infrared emissions to mitigate the threat of infrared homing ("heat seeking") surface-to-air or air-to-air missiles. Additional measures to reduce the infrared signature include special topcoat and active cooling to manage the heat buildup from supersonic flight.

The entire fuselage of the KF-23 is coated with absorbers made of metamaterial. Since the metamaterial can tailor the common waves such as light, electromagnetic waves, and sound waves, it can implement stealth capabilities for multiple bands of waves. The radio absorbers used in KF-23 are designed to ensure stealth capabilities for radar waves in the L-Band, S-Band, and UHF bands as well as X-Band. This allows KF-23 to implement stealth capabilities for radar propagation in all bands.

While the KF-23's exact RCS is classified, in 2009 KAI released information indicating that from certain angles the airplane has an RCS of 0.0002 m2 or −39 dBsm. the aircraft can mount a Luneburg lens reflector to mask its RCS.

Engines

The KF-23's dual Hanwha Aerospace JT-201 augmented turbofan engines are closely spaced and incorporate pitch-axis thrust vectoring nozzles with a range of ±20 degrees; the nozzles are fully integrated into the KF-23's flight controls and vehicle management system.

The KF-23's thrust-to-weight ratio at typical combat weight is nearly at unity in maximum military power and 1.25 in full afterburner. The fixed shoulder-mounted caret inlets are offset from the forward fuselage to divert the turbulent boundary layer and generate oblique shocks with the upper inboard corners to ensure good total pressure recovery and efficient supersonic flow compression. Maximum speed without external stores is approximately Mach 1.7 in supercruise at military/intermediate power and greater than Mach 2 with afterburners.

Helmet

The Vision Systems International helmet display is a key piece of the KF-23's human-machine interface. Instead of the head-up display mounted atop the dashboard of earlier fighters, the HMDS puts flight and combat information on the helmet visor, allowing the pilot to see it no matter which way they are facing. Infrared and night vision imagery from the Distributed Aperture System can be displayed directly on the HMDS and enables the pilot to "see through" the aircraft. The HMDS allows a KF-23 pilot to fire missiles at targets even when the nose of the aircraft is pointing elsewhere by cuing missile seekers at high angles off-boresight.

Armament

The KF-23 has 3 internal weapons bays: a large main bay on the bottom of the fuselage, and two smaller bays on the sides of the fuselage, aft of the engine inlets, a small bay for countermeasures such as flares is located behind each side bay. The main bay is split along the centerline and can accommodate 6 launchers for 6 BVR air-to air missiles or 2 air-to-air missiles and 2 standoff missiles, and each side bay has a launcher for short-range air-to-air missiles.

Protection

The KF-23 has military-grade protection against non-nuclear and nuclear shock wave EMPs.

In 2033, the Ministry of Defense launched a test operation process by integrating tactical high-energy laser(THEL) weapons into the KF-23. With a power output of 30 kW, the laser weapon is designed to shoot down enemy air-to-air missiles or drones. The Ministry of Defense plans to use technology and information obtained through the KF-23's THEL operation to operate the KF-25's laser weapon.

Operators

A squadron of KF-23 fighters flies over the skies of Busan city.

Joseon:

Royal Joseon Armed Forces
- Royal Joseon Air Force: 420 in service.
- Royal Joseon Navy: 180 in service.

Specifications

General characteristics

Crew: 1
Length: 18.93 m
Wingspan: 13.58 m
Height: 5.09 m
Empty weight: 19,700 kg
Gross weight: 29,410 kg
Max takeoff weight: 40,000 kg
Fuel capacity: 8,800 kg internally
Powerplant: 2 x Hanwha Aerospace JT-201 augmented turbofans, 26,000 lbf (116 kN) thrust each dry, 35,000 lbf (156 kN) with afterburner

Performance

Maximum speed:
- Mach 2.22 at high altitude
- Mach 1.20 at sea level
Supercruise: Mach 1.81 at high altitude
Range:
- 669 nmi (770 mi, 1,239 km) interdiction mission (air-to-surface) on internal fuel
- 760 nmi (870 mi; 1,410 km), air-to-air configuration on internal fuel
Service ceiling: 65,000 ft (20,000 m)
g limits: +9.5