TYPE: Turbojet fighter- attacker, Project

ACCOMMODATION: Pilot only

POWER PLANT: Two Nakajima Ne-230 turbojet engines, rated at 885 kp thrust each

PERFORMANCE: 505 mph

COMMENT: The Nakajima Ki-201 Karyū (“Fire Dragon”) was a Japanese turbojet fighter-attacker project designed during the final stages of World War II but which was never completed.
The Nakajima Kikka had been inspired by the successful German Messerschmitt Me 262, but the similarities to that aircraft were limited to the general configuration. On the other hand, the design team led by Iwao Shibuya based the Karyū far more closely on the German aircraft, which had already proven itself quite formidable.
The Ki-201 project was ordered by the Imperial Japanese Army between October and December 1944, with the Army laying out a performance requirement of an 800~1,000 km/h top speed, 12,000 meter practical ceiling, and 800~1,000 km range. The design was advanced by Nakajima during 1945 and the basic drawings were completed in June.
Nakajima anticipated the completion of the first Karyū by December 1945, and the first 18 units by March 1946. Most sources agree that work on the first prototype had not yet begun by the time of the Japanese surrender due to the fact that the Japanese Army had selected the Rikugun Ki 202 Shūsui-Kai (“Autumn Water, improved”) for priority development (Ref.: 24).

For comparison the German Messerschmitt Me 262A-2 Schwalbe (Swallow) armed with R-4-M Orkan,  Stab JG 7 is shown.

TYPE: Rammer aircraft

ACCOMMODATION: Pilot only

POWER PLANT: Four Type 4 Mk. 1 Model 20 solid fuel rockets with a combined 1,102 kp thrust

PERFORMANCE: 699 mph (estimated)

COMMENT: The practice of ramming, in Japanese “tai-atari”, which literally means “body crashing”, was not unique to Japan. During WW II the deliberate ramming of one aircraft by another aircraft was performed by the Russians, Germans as well as Japanese and all made ramming a part of their war doctrine.
The Japanese would use aircraft already in operational service for ramming attacks such as that Kawasaki Ki-45 and even stripped down Kawasaki Ki-61 “Hein” fighters. It was long thought that Japan never developed a dedicated rammer aircraft of its own but this is no longer the case. Recently discovered in the archives of the Japanese National Institute for Defense Studies is just such a project.
The aircraft was a joint venture between the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN), something that occurred with more regularity towards the closing stage of WW II. The design was based on the “Syusuishiki Kayaku” Rocketto (“Autumn Water”-type ram attack rocket), a project started in March 1945 for an unmanned, remote controlled anti-bomber missile. The plan was to ground launch the missile, guide it remotely towards the target, engage the target via ramming, and then recover the missile (if it survived the collision) for reuse.
Design work was carried out by the Kokukyoko (the Aeronautical Bureau) and, although a mockup was completed, the war ended before finalized production plans could be completed, let alone the missile ever being tested.
The piloted version used much the same design as the missile and was a small, tailless aircraft featuring low mounted 45′ swept wings. The fuselage was bullet shaped with a large vertical stabilizer into which the cockpit was blended. Located in the back of the fuselage were four Type 4 Mark 1 Model 20 rockets, the same as those used on the Kugisho MXYT “Oka” which on such a small aircraft pushed the maximum speed to an estimated 699 mph or just over Mach 0.91. lt is unknown if the design had swept wings because the designers  understood the principles in relation to overcoming compressibility problem at transonic speeds, or if the shape was chosen as a means to provide an angled cutting surface to facilitate ramming attacks, or as a drag reducing planform. The wings were strengthened to withstand the high impact forces experienced when striking the enemy bomber. Even though the rammer could rely on speed as a defense when under power, it still had to contend with the defensive armament of the B-29 and thought the pilot had some measure of armor plating and bulletproof glass to protect him. The aircraft was certainly capable of gliding back to base to be refueled and relaunched once it had conducted its attacks. Given the small size of the plane, no landing gear was fitted. As such, it is likely the underside of the fuselage was reinforced or had a skid installed. How it was to be launched is unknown – it could have been towed aloft, catapult launched or perhaps even vertically launched.
In a ram attack, typically the tail would be targeted because the loss of the tail assembly would send the bomber out of control. Striking the wings and engines was another focus of ramming attacks. Finally, the aircraft fuselage was the other key area to strike. The probable mission profile of the rammer flying from a ground base would include being positioned within very close proximity of likely bombing targets. With the short burn time of the rockets (8-10 seconds) the aircraft’s operational radius would have been very limited. After launching, as bombers came into range the pilot would attempt to ram into either the tail or wing of the target with the objective of severing it from the fuselage. If enough speed momentum remained after the initial hit, another ram attack would be made. Should the aircraft remain in flying condition and if the pilot did not elect to ram his entire plane into a target, he would return to base where the rockets would be replaced. If the bombers were still close by, he could fly another sortie. If the rammer was towed into the air, the rockets would most likely have been fired on approach and again after hitting a target. This would provide enough power to grant a second pass with sufficient speed to allow for significant damage to be inflicted on the bomber when it struck.
However, the Kokukyoko “Syusuishiki Kayaku” would remain a paper project only. It is unclear if the design was to be the definitive rammer model or simply a proposed concept (Ref.: Dyer III, Edwin M.: Japanese Secret Projects, Experimental Aircraft of the IJA and IJN 1939-1945, Midland Publishing, Hersham, U.K., 2010).

TYPE: High-altitude fighter. Project

ACCOMMODATION: Pilot in pressurized cockpit

POWER PLANT: One Mitsubishi Ha-211 Ru radial engine, rated at 2,200 hp

PERFORMANCE: 485 mph at 32,810 ft (estimated)

COMMENT: Preliminary discussions regarding a heavily armed high-altitude fighter were held between the Koku Hombu and Tachikawa Hikoki K. K. in mid-1942. The new aircraft was to be fitted with a pressure cabin and capable of reaching a top speed of 490 mph.  The aircraft proposed by Tachikawa, which received the Kita designation Ki-94, was of a highly unconventional design. The aircraft was a large twin-boom monoplane, powered by two 2,200 hp Mitsubishi Ha-211 Ru air-cooled radials which were mounted fore and aft of the pilot’s cockpit and drove four-blade tractor and pusher propellers. The very heavy armament that should have been mounted on the aircraft should have been powerful enough to make short work of most US heavy bombers of that area at that time. A full-scale wooden mock-up of the Ki-94 was ordered and built although at the same time a contract was placed with Nakajima for another high-altitude fighter, the Ki- 87, with less stringent range requirements as a fall-back design for the Tachikawa Ki-94.
Notwithstanding the outstanding prospective performance, which however was judged by the technical department of the Japanese Army Air Force as “unduly optimistic” and too complex, the design was discarded. But in mid-1943 Tachikawa submitted a new proposal to meet the same requirements as the competitive Nakajima Ki-87. In order to avoid confusion the Kitai designation the first Tachikawa design received the designation Ki-94-I, and the new design Ki-94-II (Ref.: 1, 24).

TYPE: Interceptor, fighter. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Kawasaki Ha 40 liquid-cooled engine, rated at 1,100 hp

PERFORMANCE: No data available

COMMENT: In the summer of 1941, Rikugun Kokugijutsu Kenkyujo (Japanese Army Aerotechnical Research Institute, short named “Kogiken”) formed a design group under the leadership of Ando Sheigo. The task was to study Japanese aviation technology in terms of what was possible at present and in the near future. Additionally, some effort was to be spent on reviewing the aircraft technology of other countries. From the results the group was to assemble and draft proposals for aircraft to fill various pre-determined roles: heavy fighter, light bomber, heavy bomber and reconnaissance. For a bigger idea pool, Imperial Japanese Army (IJA) main aircraft providers, Kawasaki and Tachikawa, were invited to join the group, too. In that period projects such as Kogiken Plan III Revised light bomber and Kogiken Plan V Revised light bomber were designed and proposed to the IJA.
Among fighter designs the Kogiken Plan I Type A was a single seat heavy fighter and a Japanese adaption of the Bell P-39 “Airacobra” mid-fuselage engine concept. The aircraft was designed end 1941 and should be powered by a single Kawasaki Ha 40 liquid-cooled in-line engine, derived from the German Daimler-Benz DB 601A. The engine was installed immediately aft the cockpit driving a four-bladed puller propeller via an extension shaft. A tricycle landing gear was provided similar to the Bell P-39. Armament consisted of 37 mm Ho-203 or 20 mm Ho-5 canon firing through the propeller hub and two wing-mounted 12.5 mm Ho-103 guns. No further details are known, the project never left the drawing board (Ref.: Parts from Unicraft).