Japan has been trying to get its own stealth fighter plane for a while now. After the U.S. Congress announced that the F-22 would not be available for foreign countries because of its advanced stealthy technology, the Japanese Ministry of Defense decided to start a project of its own. But except for the announcement of the F-3 (ATD-X project at the time) and the maiden flight of the X-2 “Shinshin” prototype developed by Mitsubishi Heavy Industries in 2016, not much has been disclosed about the Japanese development of a 5th generation plane.

Only few details are known yet and some of them date back to the first models produced, when no prototype was even built yet.

Unlike the American F-22, the F-3 should use 3D vector thrusting. There has been a lot of debate around vector thrusting since the first development of 5th gen stealth fighters. So far, it is a choice between either more thrust or more maneuverability. With its Su-57, Russia has definitely chosen maneuverability, giving up on back stealth to focus only on reducing its front Radar Cross Section (RCS). The circular nozzle on the Russian Iwd.30 exhausts provides a lot of radio wave reflection.

But the 3D vector thrusting of the X-2 is quite different. It actually uses a design similar to the X-31, a German and U.S. project plane, and to the F-18 HARV developed by NASA, with three independent paddles at the back of the exhaust that gives control over pitch, yaw and roll. Compared to a circular exhaust, the three paddles would take in a lot of temperature, but the X-31 and HARV have proven that it was doable.

The F-3 should also be equipped with an Active Electronically Scanned Array like most current fighters, and a Self-Repairing Flight Control Capability which would allow the pilot to monitor damages done to the flight control surfaces.

To help in continuing the development of the F-3, Japan has sent a “request for information” (RFI) to western constructors, with more detailed requests for Washington and London. It is the third demand of this kind to be sent by Japan, as the first two did not yield any satisfying proposal from constructors.

Even though the X-2 has been a completely endemic project, that RFI could mean that Japan would use an existing plane frame to build its own fighter. According to Reuters, a representative of the Ministry of Defense declared: “We are considering domestic development, joint development and the possibility of improving existing aircraft performance, but we have not yet come to any decision.”

The specific demands targeted at British and U.S.-based constructors would hint at the use of either the F-35 design or the Typhoon Eurofighter, even though the latter was not designed with stealth as a priority.

The need for a new air superiority fighter is growing for Japan, as it has accused China of repeatedly violating its airspace in the last years, especially in the disputed East China Sea islands.