Category Archives: Fighterbomber


Aichi M6A “Seiran” (“Mountain Haze”), 631st Kokutai, (MPM Models)

TYPE: Submarine-launched attack floatplane


POWER PLANT: One Aichi “Atsuka” Type 31 liquid-cooled engine, rated at 1,400 hp

PERFORMANCE: 295 mph at 17,060 ft

COMMENT: To equip the I-400 class submarine aircraft carriers, the Imperial Japanese Navy Air service requested for an attack aircraft with a range of 1,000 mi and a speed of 345 mph. Aichi aircraft company proposed a design on the basis of the Yokosuka D4Y1 “Suisei” that Aichi was already manufacturing under license. The D4Y1 was a relatively small single-engine carrier dive bomber with exceptionally clean lines and high performance. Detailed engineering studies commenced in an effort to modify the “Suisei” for use aboard the I-400 submarines but the difficulties in doing so were eventually judged insurmountable and a completely new design was initiated.
Aichi’s final design, designated M6A1, was a two-seat, low-winged monoplane powered by an Aichi “Atsuka” engine, a license-built copy of the German Daimler-Benz DB 602  liquid-cooled engine. The aircraft was fitted with detachable twin floats to increase its versatility. If conditions permitted, these would allow the aircraft to alight next to the submarine, be recovered by crane and then re-used. The floats could be jettisoned in flight to increase performance or left off altogether for one-way missions. The “Seiran’s” wings rotated 90 degrees and folded hydraulically against the aircraft’s fuselage with the tail also folding down to allow for storage within the submarine’s 11 ft diameter cylindrical hangar.
As finalized, each I-400 class submarine had an enlarged watertight hangar capable of accommodating up to three M6A1s. The “Seirans” were to be launched from an 85 ft compressed-air catapult mounted on the forward deck. A well-trained crew of four men could roll a “Seiran” out of its hangar on a collapsible catapult carriage, attach the plane’s pontoons and have it readied for flight in approximately 7 minutes.
The first of eight prototypes was completed in October 1943, commencing flight testing in November that year. A problem with overbalance of the auxiliary wings was eventually solved by raising the height of the tail fin. Further testing was sufficiently successful for production to start in early 1944.  Owing to the reduced carrier submarine force, production of the “Seiran” was halted, with a total of 28 completed. In mid 1945, it was planned to attack the American base at Ulithi Atoll where forces, including aircraft carriers, were massing in preparation for attacks on the Japanese Home Islands. The flotilla departed Japan on 23 July 1945 and proceeded towards Ulithi. On 16 August, the flagship I-401 received a radio message from headquarters, informing them of Japans surrender and ordering them to return to Japan. All six “Seirans” on board the two submarines, having been disguised for the operation as American planes in violation of the laws of war, were catapulted into the sea with their wings and stabilizers folded (for the  submarine I-401) or pushed overboard (for the submarine I-400) to prevent capture (Ref.: 24).

Kawanishi N1K2-J “Shiden Kai” (“Violet Lightning”,“George”) , (Hasegawa)

TYPE: Interceptor fighter


POWER PLANT: One Nakajima NK9H-S “Homare 23” radial engine, rated at 2,000 hp

PERFORMANCE: 369 mph at 18,375 ft

COMMENT: In 1943, while the Kawanishi N1K1-J “Shiden” was being evaluated by the Japanese Navy, preliminary design work on an advanced version of the aircraft had already begun at Kawanishi and the N1K1-J was placed in production only as a stop-gap measure pending availability of a new version designed N1K2-J. The prime reason for designing the N1K2-J was to eliminate the need for a long and complex undercarriage of the earlier version, and consideration was also given to simplifying construction and maintenance. To achieve this goal, the wings were moved to the lower fuselage, conventional main gear legs of reduced length were adopted and the fuselage and tail surfaces were entirely redesigned. The result was a virtually new aircraft retaining only the wings and armament of the N1K1-J.
The prototype of the N1K2-J “Shiden-Kai” (“Violet Lightning-Modified”) was flown for the first time on December, 1943, and successfully completed its manufacture’s trials within fifteen weeks before handed over to the Navy in April 1944. Despite persistent difficulties with the unreliable “Homare 21” engine, the N1K2-J had all the qualities of a successful fighter aircraft and production aircraft began rolling off the assembly lines. Unfortunately for the Japanese, the production fell considerably behind schedule as bombing by Boeing B-29 “Superfortresses” led to shortage of engines and equipment. The companies involved in the “Shiden-Kai” production program delivered only a token number of aircraft.
In operation the N1K2-J revealed itself as a truly outstanding fighter capable of meeting on equal terms of best Allied fighter aircraft. Against the high-flying B-29s the “Shiden-kai” was less successful as its climbing speed was insufficient and the power of the “Homare 21” fell rapidly at high altitudes.
In total 423 N1K2-J “Shiden-Kai” were produced including eight prototypes (Ref.: 1).

Nakajima A6M2-N “Rufe”, Sasebo Naval Flying Group

TYPE: Float seaplane fighter


POWER PLANT: One Nakajima NK1C “Sakae” 12 radial engine, rated at 950 hp

PERFORMANCE: 270 mph at 16,400 ft

COMMENT: The Nakajima A6M2-N (Navy Type 2 Interceptor/Fighter-Bomber) was a single-crew floatplane based on the Mitsubishi A6M “Zero” Model 11. The Allied reporting name for the aircraft was “Rufe”.
The A6M2-N floatplane was developed from the Mitsubishi A6M “Zero” Type 0, mainly to support amphibious operations and defend remote bases. It was based on the A6M-2 Model 11 fuselage, with a modified tail and added floats.
The aircraft was deployed in 1942, referred to as the “Suisen 2” (“Hydro fighter type 2”), and was only utilized in defensive actions in the Aleutians and Salomon Islands operations. Such seaplanes were effective in harassing American PT boats at night. They could also drop flares to illuminate the PTs which were vulnerable to destroyer gunfire, and depended on cover of darkness.
The seaplane also served as an interceptor for protecting fueling depots they also served as fighters aboard seaplane carriers “Kamikawa Maru” in the Salomons and Kuriles areas and aboard Japanese raiders “Hokaku Maru” and “Aikoku Mari” in Indian Ocean raids. In the Aleutian Campaign this fighter engaged with RCAF Curtiss P-40 “Warhawk”, Lockheed P-38 “Lightning” fighters and Boeing B-17 “Flying Fortress” bombers. The aircraft was used for interceptor, fighter-bomber, and short reconnaissance support for amphibious landing, among other uses.
Later in the conflict the Otsu Air Group utilized the A6M2gs-N as an interceptor alongside Kawanishi N1K1 “Kyofu”(“Rex”) aircraft based in Biwa lake in the Honshū area.
The large float and wing pontoons of the A6M2-N degraded its performance by only about 20%. However, this caused the A6M2-N to be unable to confront the first generation of Allied fighters. A total of 327 were built, including the original prototype (Ref. 24).

Kawanishi E15K1 “Shiun” (“Violet Cloud”, “Norm”)(Aoshima, Parts Scratch-built)

TYPE: High-speed reconnaissance float plane


POWER PLANT: One Mitsubishi MK4S Kasei 24 radial engine, rated at 1,850 hp

PERFORMANCE: 291 mph at 18,700 ft

COMMENT: In 1939 the Imperial Japanese Navy instructed the Kawanishi Aircraft Company to develop a two-seat high-speed reconnaissance floatplane, which was required to have sufficient performance to escape interception by land based fighters. It was planned to equip a new class of cruisers, intended to act as a flagship for groups of submarines operating six of the new floatplanes to find targets. Kawanishi designed a single-engine low-wing monoplane, powered by a 1,460 hp Mitsubishi MK4D Kasei 14 radial engine driving two contra-rotating two-blades propellers, the first installation of contra-rotating propellers produced in Japan, while a laminar flow airfoil section was chosen to reduce drag. It had a single main float under the fuselage and two stabilising floats under the wing. The stabilising floats were designed to retract into the wing, while the central float was designed to be jettisoned in case of emergency, giving a sufficient increase in speed to escape enemy fighters. It is noteworthy to mention that similar design was chosen by Kawabishi’s engineers for the new Kawanishi N1K1 “Kyofu” float seaplane fighter.
The first prototype of Kawanishi’s design, designated E15K1 in the Navy’s short designation system made its maiden flight on 5 December 1941. Five more prototypes followed during 1941-42. Problems were encountered with the retractable stabilising floats, resulting in several accidents when the floats could not be lowered for landing, and the system was eventually abandoned, with the stabilising floats being fixed, and a more powerful Mitsubishi MK4S Kasei 24 engine fitted to compensate for the increased drag.
Despite these problems, the E15K1 was ordered into limited production as the Navy Type 2 High-speed Reconnaissance Seaplane “Shiun” Model 11. Six were sent to Palau in the South Pacific, but these were quickly shot down by Allied fighters, as the jettisonable float failed to separate on demand (although subjected to wind tunnel testing, the float separation system had never been tested on the actual aircraft). This resulted in the cancellation of production in February 1944, with only 15 “Shiuns” completed, including the six prototypes (Ref.: 24).