KF-23 Chammae

KF-23 Chammae
KF-23 Chammae flies over Naju city.
General information
Type	Air superiority fighter
National origin	Joseon
Manufacturer	Korea Aerospace Industries, Ltd.
Status	In service
Primary user	Royal Joseon Air Force *Royal Joseon Navy
History
Manufactured	2013-2023
Introduction date	15 December 2016
First flight	7 June 2013 (2013-06-07)

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.

Development

KF-23 originated from the HETF(High-End Tactical Fighter) program, which was launched to replace F-15C fighters, and supplement KF-21, 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 2007, 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 2013. 6 more prototype aircraft were built after the flight of the first prototype aircraft, and the entire test flight process ended in 2015.

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.

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 F-15E'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 110 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.

While the KF-23's exact RCS is classified, in 2009 Lockheed Martin released information indicating that from certain angles the airplane has an RCS of 0.0004 m2 or −38 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.

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.