Category Archives: Fighter

Fighter

Kokukyoko “Syusuishiki Kayaku ”, (“Autumn Water”), Unicraft Models, Resin

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).

Mitsubishi Ki-202 “Shūsui-Kai” (“Sharp Sword”) (A + V Models, Resin)

TYPE: Interceptor aircraft. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Toku Ro.3 (KR20) liquid fuel rocket engine, rated at 2,000 kp thrust plus one additional rocket, rated at 750 kp thrust

PERFORMANCE: 559 mph at 32,808 ft

COMMENT: The Mitsubishi Ki-202 “Shūsui-Kai” (translated as “Sharp Sword, improved”) was a direct development of the Mitsubishi Ki-200 “Shusui” rocket-powered interceptor aircraft. None were produced before Japan’s surrender that ended WW II.
In a split from the development of the IJ Navy Mitsubishi J8M “Shusui” and Army’s Mitsubishi Ki-200 “Shusui”, the IJ Army instructed Rikugun Kokugijitsu Kenkyujo (Army Aerotechnical Research Institute) to develop a new design originally based  on the German Messerschmitt Me 163 “Komet” (“Comet”), built in Japan as a joint Navy-Army venture.
A fundamental shortcoming of the Messerschmitt Me 163, and all other aircraft based on it, was extremely limited endurance, typically only a few minutes. The Imperial Japanese Navy proposed to improve the endurance of the J8M1 by producing a version with only one cannon, thereby saving weight and space for more fuel, designated J8M2. The Imperial Japanese Army, on the other hand, opted to keep both cannon, but enlarge the airframe to accommodate larger tanks, resulting in the Mitsubishi Ki-202 “Shusui-Kai”, which was to have been the definitive Army version of the fighter. Power was to be supplied by a 2,000 kg thrust delivering Mitsubishi Toku Ro.3 (KR20) rocket motor. An additional rocket engine with reduced thrust was used for cruising speed. Undercarriage was to have been a sprung skid and tail-wheel.
Similar development was done in Germany. The Messerschmitt Me 163 variant Messerschmitt Me 163C had a lengthened fuselage to accommodate larger fuel tanks while the Messerschmitt Me 263 was a complete new design with increased flight endurance (Ref.: 24).

Kawasaki Ki-100-I Otsu, 5th Sentai (Hasegawa)

TYPE: Fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Ha 112-II radial engine, rated at 1,500 hp

PERFORMANCE: 360 mph at 19,700 ft

COMMENT: In mid-1944, the Kawasaki Ki-61”Hien” (Allied code “Toni”) was one of the best fighters of the Imperial Japanese Army Air Service. It was the only production Japanese fighter to have an in-line Kawasaki Ha-40 power plant, a Japanese adaptation of the German Daimler-Benz DB 601 engine, as well as the first one with factory-installed armor and self-sealing fuel tanks. It also had respectable performance, more in line with contemporary American and European designs of the time, with speed and rate of climb emphasized instead of maneuverability and range. It was an effective design, but suffered from engine shortages and reliability problems.
These problems as well as the performance advantage of enemy fighters, especially the Grumman F6F “Hellcat”, led to the development of an improved model, the Ki-61-II (later Ki-61-II-KAI), powered by the new 1,500 hp Kawasaki Ha 140 engine, which was unfortunately heavier than the Ki-61-I-KAIc it replaced. Maximum speed increased from 370 to 380 mph as well as general performance. However, it was never able to perform as planned due to the continued degradation of quality of the engine’s assembly line, with far fewer engines produced than were required, while many of the engines that were built were rejected due to poor build quality. At this point of the war, the IJAAF was in desperate need of effective interceptors to stop the enemy bomber raids over the Japanese mainland, so in October 1944 it was ordered that a 1,500 hp Mitsubishi Ha 112-II “Kinsei” (“Venus”), a 14-cylinder, two-row radial engine should be installed in those airframes. The need for the re-engined fighter was made yet more urgent on January 1945, when a Boeing B-29 “Superfortress” raid destroyed the engine’s production plant, leaving 275 finished Ki-61s without a power plant.
The Mitsubishi Ha-112-II was some lighter than the Ha-140 and produced the same power more reliably. After the study of an imported German Focke-Wulf Fw 190, an example of an aircraft in which a wide radial engine had been successfully installed in a narrow airframe, three Kawasaki Ki-61-II-KAI airframes were modified to carry this engine and to serve as prototypes.  As a result, on February 1945, the new model, Kawasaki Ki-100, was flown for the first time. Without the need for the heavy coolant radiator and other fittings required for a liquid-cooled engine, the Ki-100 was lighter than the Ki-61-II, resulting in a reduction of wing loading. This had an immediate positive effect on the flight characteristics, enhancing landing and takeoff qualities as well as imparting increased maneuverability, including a tighter turning circle.
The army general staff was amazed by the flight characteristics of the plane, which surpassed the Ki-61 in all but maximum speed (degraded by a maximum of 18 mph]by the larger area of the radial engine’s front cowling, and the model was ordered to be put in production. The company’s name was Ki-100-1-Ko. All of the airframes were remanufactured from Ki-61-II Kai and Ki-61-III airframes; the integral engine mount/cowling side panel was cut off the fuselage and a tubular steel engine mount was bolted to the firewall/bulkhead. Many of the redundant fittings from the liquid-cooled engine, such as the ventral radiator shutter actuator, were still kept. The first 271 aircraft, or Kawasaki Ki-100-1-Ko, with the raised “razorback” rear fuselage were rolled out of the factory between March and June 1945. A further 118 Ki-100 I-Otsu are built with a cut-down rear fuselage and new rear-view canopy from May through to the end of July 1945. This version also featured a modified oil cooler under the engine in a more streamlined fairing. In total 396 Kawasaki Ki-100 were built before Japan surrendered (Ref.: 24).

Mitsubishi Ki-200 “Shusui” (“Sharp Sword”) (Hasegawa)

TYPE: Interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Toku-Ro.2 /KR10) bi-fuel liquid rocket, rated at 1,500 kp thrust

PERFORMANCE: 559 mph at 32,808 ft

COMMENT: The Mitsubishi J8M “Shūsui” (literally “Autumn Water”, used as a poetic term meaning “Sharp Sword” deriving from the swishing sound of a sword) was a Japanese WW II rocket-powered interceptor aircraft closely based on the German Messerschmitt Me 163 “Komet” (Comet”). Built as a joint project for both the Japanese Navy and the Army Air Services, it was designated J8M (Navy) and Ki-200 (Army).
The Ki-200 and the J8M1 differed only in minor items, but the most obvious difference was the JAAF’s Ki-200 was armed with two 30 mm Type 5 cannon (with a rate of fire of 450 rounds per minute and a muzzle velocity of 720 m/s, while the J8M1 was armed with two 30 mm Ho-105 cannon (rate of fire 400 rounds per minute, muzzle velocity 750 m/s). The Ho-105 was the lighter of the two and both offered a higher velocity than the German MK 108 cannon of the Messerschmitt Me 163 (whose muzzle velocity was 520 m/s).
The Toko Ro.2 (KR10) rocket motor did not offer the same thrust rating as the original, and Mitsubishi calculated that the lighter weight of the J8M1 would not offset this. Performance would not be as good as that of the Me 163 “Komet”, but was still substantial. The engine still used the German propellants of T-Stoff oxidizer and C-Stoff fuel (hydrogen peroxide/methanol-hydrazine), known in Japan as “Ko” and “Otsu” respectively.
At the end of the war “Shusui” production was already under way. Additionally, the Navy had instructed Mitsubishi, Nissan and Fuji to design a further Navy version as J8M2 with only one cannon thus giving additional space for more fuel and by that more endurance, while the Army ordered Rikugun Kokugijutsu Kenkyujo the development of an enlarged version of the Ki-200 with increased fuel tankage, known as Mitsubishi Ki-202 “Shusui Kai to be built by Mitsubishi (Ref.: 1, 24).

Tachikawa Ki-94-I (A+V Models, Resin)

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).

Kogiken Plan I Type A Heavy fighter (Unicraft, Resin)

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).

Mitsubishi Ki-109b (2nd Chutai, 107th Sentai)(LS-Models)

TYPE: Heavy interceptor

ACCOMMODATION: Crew of four

POWER PLANT: Two Mitsubishi Ha-104 radial engines, rated at 1,900 hp each

PERFORMANCE: 324 mph at 19,980 ft

COMMENT: In early 1943 the Mitsubishi Ki-67 heavy bomber then undergoing flight trials had proved that despite its size and weight it was fast and manoeuvrable. Consequently it was suggested that the Ki-67 be used as a basis for a hunter-killer aircraft. The project received the designation Ki-109 and two versions were built. The Ki-109a, nick-named “Killer”, was to mount in the rear fuselage two oblique-firing 37 mm Ho-203 cannon while the Ki-109b, the “Hunter”, was to be equipped with radar and a 40 cm search light. However, soon thereafter, the project was redirected and a standard 75 mm Type 88 anti-aircraft cannon was to be mounted in the nose. It was hoped that with this large cannon the aircraft could be able to fire on the Boeing B-29s while staying well out of range of their defensive armament. As the authorities anticipated that, initially at least, the B-29s would have to operate without fighter escort, the project was found sound and feasible and Mitsubishi were instructed in early 1944 to begin designing the aircraft which retained the Ki-109 designation.
Ground and inflight test firing of the heavy gun were sufficiently successful and an initial order of 44 aircraft was placed. Fifteen shells were carried for the 75 mm Type 88 cannon which were hand-loaded by the co-pilot, and the sole defensive armament consisted of a flexible 12.7 mm machine-gun in the tail turret. The rest of the airframe and the power plant were identical to those of the Ki-67. Despite the lack of high-altitude performance the Ki-109 was pressed into service, but, by the time enough aircrafts were on hand, the B-29s had switched to low-altitude night operations. A total of 22 Ki-109s were built by Mitsubishi Jukogyo K.K. (Ref.: 1).

Nakajima Ki-43-II KAI ‘Hayabusa’, (‘Peregrine Falcon’, ‘Oscar’), 50th Sentai, 3rd Chutai, (Hasegawa)

TYPE: Interceptor fighter, fighter bomber

ACCOMMODATION: Pilot only

POWER PLANT: One Nakajima Ha.35/21 air-cooled radial engine, rated at 1.130 hp

PERFORMANCE: 320 mph at 19,680 ft

COMMENT:  Combat experiences with the Ki-43-I dictated a number of changes in the design of the aircraft that led to the development of the Nakajima Ki-43-II-KAI. It entered service in summer 1943 and served over every theatre to which the JAAF was committed. The Ki-43-II-KAI was capable to out-maneuvering every Allied fighter it encountered and its element was dog-fighting, but the Lockheed P-38 ‘Lightning’, the Republic P-47 ‘Thunderbolt’ and the north American P-51 ‘Mustang’ could all out-dive and out-zoom the Japanese fighter which could not withstand the greater firepower of the Allied types, frequently disintegrating in the air when hit. More than 5.000 Ki-43-II ‘Hayabusa’ were built by Nakajima and Tachikawa (Ref.: 13)

Nakajima Ki-43-II-Otsu ‘Hayabusa’ (‘Peregrine Falcon’, ‘Oscar’) of Headquaters Chutai, 77th Hiko Sentai (Hasegawa)

TYPE: Fighter, fighter bomber

ACCOMMODATION: Pilot only

POWER PLANT: One Nakajima Ha.115 radial engine, rated at 1,130 hp

PERFORMANCE: 320 mph at 19,680 ft

COMMENT: The Nakajima Ki-43 ‘Hayabusa’was a single-engine land-based tactical fighter used by the Imperial Japanese Army Air Force in WW II. It was light and easy to fly and became legendary for its combat performance in East Asia in the early years of the war. It could outmaneuver any opponent, but did not have armor or self-sealing tanks, and its armament was poor until its final version, which was produced as late as 1945. Allied pilots often reported that the nimble Ki-43s were difficult targets but burned easily or broke apart with few hits. In spite of its drawbacks, the Ki-43 shot down more Allied aircraft than any other Japanese fighter and almost all the JAAF’s aces achieved most of their kills in it. Prototypes for the Nakajima Ki-43-II flew in February 1942. The Ha-25 engine was upgraded with the 2-stage supercharger, thus becoming the more powerful Nakajima Ha-115 engine, which was installed in a longer-chord cowling. The new engine turned a three-bladed propeller. The wing structure, which had suffered failures in the Ki-43-I, was strengthened and equipped with racks for drop tanks or bombs. The Ki-43-II was also fitted with 13 mm armor plate for the pilot’s head and back, and the aircraft’s fuel tanks were coated in rubber to form a crude self-sealing tank. Nakajima commenced production of the Ki-43-II at its Ota factory in November 1942. Production was also started at the Tachikawa Hikoki KK and the 1st Army Air Arsenal (Tachikawa Dai-Ichi Rikugun Kokusho), also at Tachikawa. Although Tachikawa Hikoki successfully managed to enter into large-scale production of the Ki-43, the 1st Army Air Arsenal was less successful – hampered by a shortage of skilled workers, it was ordered to stop production after 49 Ki-43s were built. Nakajima eventually ceased production in mid-1944 in favor of the Nakajima Ki-84 ‘Hayate’, but the Tachikawa Hikoki continued to produce the Ki-43. Total production amounted to 5,919 aircraft. Many of these were used during the last months of the war for kamikaze missions against the American fleet (Ref.: 24).

Kawasaki Ki-45-KAI-Otsu “Toryu”(“Dragon Killer”, “Nick”), 4th Sentai, 2nd Chutai, (Hasegawa)

TYPE: Twin-engined heavy fighter, ground attack aircraft

ACCOMMODATION: Pilot and radio-operator/gunner

POWER PLANT: Two Mitsubishi Ha-102 radial engines, rated at 1,050 hp each

PERFORMANCE: 335 mph at 19,685 ft

COMMENT: The Kawasaki Ki-45-Kai Toryu was probably the most manoeuvrable twin-engined fighter to be employed operationally by any combatants during WW II.  Although outclassed in the air-to-air combat arena by Allied single-seat fighters, the Toryu was never to be considered an “easy kill” and it was to prove capable of out-manoeuvring the Lockheed P-38 “Lightning” without difficulty. Furthermore, the Ki-45 was very effective in ground attacks. A special version, the Ki-45-KAI-Otsu, was equipped with 20-mm Ho-3 cannon, too low-firing in air combat, but, as the Imperial Army enjoyed air superiority over the areas in which the Toryu was operating, it was found to be particularly efficacious in attacks on US Navy PT boats and other smaller vessels and in ground-attack role. In late 1943 the 20-mm Ho-3 cannon was replaced by a hand loaded 37-mm Type 98 gun, making this variant even more successful for close-support duties (Ref.: 5).