Overview The F-X is a twin engine stealth fighter designed for achieving
air superiority. By the Japanese MoD's own terminology, the technology and capabilities the F-X possesses will classify it as a sixth generation fighter jet. Defense Minister
Taro Kono has stated that the F-X will possess strong network capabilities and will carry more missiles than the F-35. In the design process, conceptual designs of the F-X are made, then passed through a
3-D digital mock-up system. Designs are based on the assumed function and performance of the F-X, and then installed in a research flight/battle simulator developed by the
Technical Research Division. Data on avionics, stealth and engine characteristics are inputted into the simulator, and are then tested by JASDF pilots. Through air-to-air combat simulations, the effectiveness and improvements to the mock-up design are gauged. Compared to its predecessor, the F-X replaces the usage of conventional hydraulic systems with electric actuators. According to the MoD's evaluation, the reason for selecting electric actuators over hydraulic systems is because of the complexity of designing the interior of the stealth fighter. When designing the stealth shape of the aircraft, the internal weapon bay and intake air-ducts must be accounted for. However, problems arise with installing hydraulic system piping due to design considerations such as rigidity and length. The adoption of electric actuators eliminates these constraints because they are only connected via electric wiring. This results in simplified installation and reduced restrictions, allowing more flexibility in designing the body of the aircraft. The electric actuators are used in the fighter's flight control systems and undercarriage/wheel braking systems. To achieve a lightweight body structure, the F-X implements several technologies and manufacture/design techniques. One method involves reducing or eliminating the use of
fasteners by bonding composite materials together through adhesive molding. This method is dubbed the "integrated/fastenerless structure" technology.
Heat shield technology is placed around the engines to allow aluminum alloys and
carbon-fiber reinforced polymer (CFRP) to be applied to reduce weight. High-efficiency/high-accuracy structural analysis techniques used for the F-X involve creating
finite element method (FEM) models using
computer-aided design (CAD) to study and create stress analysis standards for the F-X. The F-X's predecessor, the F-2, introduced integrated molding and CFRP material to reduce its overall weight, but the molding technique applied only on the bottom plates of the wings; requiring fasteners to be placed through the upper plates in the main wing and other areas using fasteners on both plates. In comparison, the F-X expands the application of CFRP and adhesive molding to the entire
fuselage. From the MoD's research, it was shown that adopting the new design methods can reduce the structural mass of the F-X's airframe by 11.6% and – for a portion of the middle fuselage – reduce working man-hours by 66% compared to conventional approaches. To cope with the heat produced by the avionic systems, a small dedicated heat transfer system is installed in the F-X to assist its air cycle and liquid cooling system. The heat transfer system is modeled on the
vapor-compression refrigeration cycle.
Avionics To improve detection against stealth aircraft, the F-X utilizes integrated sensors. The sensors include: an
active electronically scanned array (AESA) radar, passive radio frequency (RF) sensor, and an infrared camera. Both the AESA radar and RF sensor utilize
Gallium nitride (GaN) to improve its performance.
Cockpit The helmet-mounted display features a wide field of vision, binocular, multi-color display, voice recognition and
3-D sound.
Stealth To minimize its radar cross section, F-X physical design features serpentine air-ducts and an internal weapons bay. Electromagnetic wave absorbers are applied to the air-ducts and engines to reduce the amount of radar reflection. The absorber is said to be of carbon-based material. According to results of tests conducted, the RCS reduction done from the absorbers has the equivalent effect of reducing detection range from radar threats by about half.
Metamaterials are also used to reflect radio waves. The metamaterials consists of various materials including small pieces of metals and dielectric. The metamaterials are applied on the
pulse doppler system as part of a radio wave reflection control technology on board the F-X. To avoid having its radar emissions detected, the F-X maximizes its usage of passive detection. Its sensor programs also operate its radar emissions in a way that reduces the likelihood of counter detection during radar emissions.
Engine Early in development the F-X was to be powered by two XF9 engines. In 2018, the officially publicized thrust level of the prototype engine was "11 tons (107 kN / 24,000 lbf) or more" in military thrust and "15 tons (147 kN / 33,000 lbf) or more" with afterburner. The XF9 is designed to be adaptable to a wide range of thrust level, higher or lower, depending on requirement; and the future fighter engine program is conducted with a target maximum thrust of 20 tons (196 kN / 44,000 lbf) in mind, which was unveiled at the ATLA Technology Symposium 2018. The XF9 possesses a high combustion temperature at 1800 °C. Noteworthy of the XF9 is its slim size relative to its power. For instance, the engine inlet of the XF9 is 30% smaller than the
General Electric F110 used on the F-2. The engines incorporate
three dimensional thrust vector nozzles to allow the aircraft to achieve high maneuverability and improve stealth capabilities. The engine's thrust vector nozzle can deflect thrust up to 20 degrees in all circumference directions. December 2021 a memorandum was signed between Japan and the UK to co-operate on producing a joint demonstrator design for a sixth generation aircraft engine through engine manufacturers IHI and Rolls-Royce, a joint viability study had been underway for a while. Japan's defense ministry said efforts would commence in its next financial year, which began on April 1, 2022. Later the Italian manufacturer Avio Aero joined as a partner on the engine development.
Armaments The
ASM-3 has been developed for the F-X to use as the F-2 gets phased out. The F-X will be armed with a
microwave weapon to disrupt incoming missiles.
Drone control Japan plans on introducing
unmanned combat aerial vehicles that can operate alongside the F-X, called the Combat Support Unmanned Aircraft. The drone program is similar to the
Kratos XQ-58 Valkyrie or
Boeing Airpower Teaming System project in which the drone acts as a "
loyal wingman" to the controlling aircraft. There are two versions of the drone: one that is a sensor carrier and scouts for targets, and another that fires munitions and directs incoming missiles away from the parent aircraft. Both versions share the same design as each other. The drones are expected to be fully developed by the 2030s. == Significance and issues ==