Category Archives: Fighterbomber

Fighterbomber

Yokosuka D3Y2-K “Myojo Kai” (“Venus Modified”) (Valom)

TYPE: Dive bomber, trainer, suicide aircraft

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi “Kinsai 62” radial engine, rated at 1,560 hp

PERFORMANCE: 292 mph

COMMENT: The Yokosuka D3Y “Myojo” (“Venus”) was a Japanese two-seat dive bomber/trainer designed and built by the Yokosuka Naval Air Technical Arsenal derived from the Aichi D3A. It was made nearly entirely of wood in an attempt to conserve valuable resources. Upon Japan’s surrender, the project came to a halt with only a few aircraft delivered.
The D3Y was a two-seat bomber trainer constructed of wood, so as not to use more valuable materials. It was based on the successful Aichi D3A, with design starting in late 1942. Like the D3A, it was a two-seat low-winged monoplane with a fixed tailwheel undercarriage. To allow construction by unskilled workers, the elliptical wing and rounded tail of the D3A were replaced by straight tapered alternatives, while the fuselage was lengthened to improve stability. Two prototypes were built during 1944, but these proved heavier than expected. Three production aircraft, which were redesigned to save weight, were completed for the Imperial Japanese Navy Air Force (IJNAF) before the end of the war, and officially designated the Navy Type 99 Bomber Trainer Myojo Model 22.
In Yokosuka’s design bureau two different variants of the basic design were on the drawing board.
The D3Y1-K “Myojo” (Navy Type 99 Bomber Trainer Myojo Model 22) was a two seat wooden dive-bomber trainer. Powered by a 1,300 hp Mitsubishi Kinsei 54 radial engine, based on the Aichi D3A2-K, the aircraft featured some significant changes to allow production in wood. Two prototypes and three production aircraft were completed before the final collaps.
The second design, a single-seat D3Y2-K Special Attacker Myojo Kai (“Venus Modified”) for suicide missions was initiated early in 1945. Powered by a 1,560 hp Mitsubishi Kinsei 62 and fitted with a jettisonable undercarriage on take-off since the aircraft was not expected to return. This version was to have been armed with two 20mm Type 99 MK1 cannon in the engine cowling was to carry a single bomb up to 800 kg. The prototype had not been completed when the war ended, and the planned monthly production of thirty D5Y-1s, as the aircraft had been redesignated, was never undertaken (Ref.: 1, 24).

Kugisho (Yokosuka) R2Y2 “Keiun-Kai”(Airmodel, Resin)

TYPE: Fast attack bomber

ACCOMMODATION: Crew of two

POWER PLANT: Two Mitsubishi Ne 330 axial-flow turbojet engines, rated at 1,320 kp each

PERFORMANCE: 495 mph (estimated)

COMMENT: In late 1944, Kugisho (a WW II acronym for Dai-Ichi Kaigun Koku Gijitsusho, First Naval Air Technical Arsenal. Kugisho was based at Yokosuka, hence the type is often incorrectly designated Yokosuka) approached the Imperial Japanese Navy (IJN) and informed them that the R2Y1‘s airframe was readily adaptable to other roles, including that of a fast attack bomber. To heighten the interest, it was proposed that the Ha-70 10 engine be replaced with two Mitsubishi Ne330 axial flow turbojets, each of the engines being slung under the wings in nacelles. The fuselage space vacated by the Aichi engine would be replaced with fuel tanks. For weapons, the aircraft would carry one 1,800kg bomb and have a cannon armament in the nose. With the introduction of the Ne330 engines, the maximum speed was expected to be 495mph, superior to the projected 447 mph top speed of the Aichi engine model. With these advantages in mind, the IJN approved that work should begin on designing the R2Y2, the turbojet powered “Keiun” which was sometimes referred to as the “Keiun-Kai”, as well as permitting the R2Y1 to be completed as an airframe demonstrator to test the handling characteristics.
Even before the destruction of the first R2Y1, a second example was being constructed and design work for the R2Y2 was underway.
Contemporary sources show no less than four versions for how the R2Y2 may ultimately have appeared. The first version had the Ne330 engines in underwing nacelles. The second version showed the two engines buried within the fuselage with wing root air intakes and narrow jet nozzles. The third version removed the wing intakes and replaced them with a nose intake, but it retained the narrow nozzles. Finally, the fourth version was similar to the third except the engine nozzles were larger.
The first design is considered by most to be the initial R2Y2 concept while the other three are subject to debate. In part, this is due to the fact that the Japanese had very little time to explore various installations of turbojets in airframes. The easiest means to place turbojets on aircraft was by using nacelles and this was seen in the Nakajima “Kitsuka”, Nakajima Ki-201 “Karyu” and proposed Kugisho “Tenga” and Kawanishi K-200.
Even the Germans with their turbojet experience did not fully understand the effects of a long nose intake feeding a high performance jet buried in a combat fighter’s fuselage. Messerschmitt, when they began to study how to start the Messerschmitt Me P.1101 Vl second generation jet fighter, catalogued the obstacles that needed to be overcome. They included the effects of engine operation on the fuselage integrity, ensuring the nose intake was properly positioned and shaped for maximum airflow, making sure the intake tube was made as smooth as possible to minimize air restrictions, how to protect the rear of the aircraft from the heat generated by the exhaust thrust, the effects of reduced airflow on thrust due to flight angles and more. The Germanswere at least able to devote some time to investigating these problems and providing promising solutions to them.
This was time however, that the Japanese simply did not have. Up until the construction of the and the planned Focke-Wulf Ta 183, all of the War time jet designs flown by the Luftwaffe had nacelle mounted turbojets, e.g. Messerschmitt Me 262. The Japanese may not have been made fully privy to the latest German jet engine technology as it pertained to long intakes before the war ended.
It is within reason to suggest that the R2Y2 with the wing root intakes could have been under consideration since it would be a logical development, especially since such intake arrangements were not entirely new. The third and fourth designs may or may not have been post-war conjecture.
Unfortunately for Kugisho and the IJN, the R2Y2 would never be brought to full production. With the end of the war, the second R2Y1 prototype remained incomplete and the R2Y2 would forever remain a design board aircraft (Ref.: Dyer III, Edwin M.: Japanese Secret Projects, Experimental Aircraft of the IJA and IJN 1939-1945, Midland Publishing, Hersham, U.K., 2010).

Mitsubishi A6M5c ‘Rei-sen’ (“Zero”, “Zeke”), (Hasegawa)

TYPE: Carrier-borne fighter, fighter-bomber

ACCOMMODATION: Pilot only

POWER PLANT: One Nakajima NK1F “Sakae 21” radial engine, rated at 1,100 hp at 9,350 ft

PERFORMANCE: 351 mph at 19,685 ft

COMMENT: The Mitsubishi A6M “Zero” was the best known Japanese warplane of WW II. A6M “Zeros” were predominantly used by the Imperial Japanese Navy Air Service (IJN) on aircraft carriers, and also by its land-based fighter units. At the start of the Pacific War in 1941, the A6M constituted about 60% of the IJN fighter force. It took part in carrier operations throughout much of the Pacific Ocean, as well as over the northeast Indian Ocean
The Mitsubishi A6M “Zero” is a long-range fighter aircraft formerly manufactured by Mitsubishi Aircraft Company. Officially, the A6M was designated as the Mitsubishi Navy Type 0 carrier fighter (“Rei-shiki-kanjō-sentōki”), or the Mitsubishi A6M “Rei-sen”. The A6M was usually referred to by its pilots as the “Reisen” (Zero fighter), “0” being the last digit of the Imperial Year 2600 (1940) when it entered service with the Imperial Navy. The official Allied reporting name was “Zeke”, although the use of the name “Zero” was later adopted by the Allies as well.
The “Zero” was considered the most capable carrier-based fighter in the world when it was introduced early in WW II, combining excellent maneuverability and very long range. The IJN also frequently used it as a land-based fighter.
With its low-wing cantilever monoplane layout, retractable, wide-set conventional landing gear and enclosed cockpit, the “Zero” was one of the most modern carrier based aircraft in the world at the time of its introduction. It had a fairly high-lift, low-speed wing with very low wing loading. This, combined with its light weight, resulted in a very low stalling speed of well below 69 mph. This was the main reason for its phenomenal maneuverability, allowing it to out-turn any Allied fighter of the time.
The “Zero” quickly gained a fearsome reputation. Thanks to a combination of unsurpassed maneuverability — even when compared to other contemporary Axis fighters — and excellent firepower, it easily disposed the motley collection of Allied aircraft sent against it in the Pacific in 1941. It proved a difficult opponent even for the British Supermarine “Spitfire”.  Although not as fast as the British fighter, the “Zero” could out-turn the “Spitfire” with ease, sustain a climb at a very steep angle, and stay in the air for three times as long. In early combat operations, the “Zero” gained a legendary reputation as a dogfight achieving an outstanding kill ratio of 12 to 1, but by mid-1942 a combination of new tactics and the introduction of better equipment enabled Allied pilots to engage the “Zero” on generally equal terms. By 1943, due to inherent design weaknesses and an inability to equip it with a more powerful aircraft engine, the “Zero” gradually became less effective against newer Allied fighters. By 1944, with opposing Allied fighters approaching its levels of maneuverability and consistently exceeding its firepower, armor, and speed, the A6M had largely become outdated as a fighter aircraft. However, due to design delays and production difficulties, which hampered the introduction of newer Japanese aircraft models, the “Zero” continued to serve in a front line role until the end of the war in the Pacific. During the final phases, it was also adapted for use in Kamikaze operations.
Japan produced more “Zeros” than any other model of combat aircraft during the war. When the war in the Pacific Area of Action ended, 10,939 aircraft have been built by Mitsubishi Jukogyo K.K. and Nakajima Hikoki K.K. in four major variants A6M2, A6M3, A6M5, and A6M8, each variant including several subtypes. Nakajima built a float-plane variant, the Nakajima A6M2-N, Allied reporting name “Rufe”.
The Mitsubishi A6M5c, Model 52 Hei, featured an armament change: One 13.2 mm Type 3 machine gun was added in each wing outboard of the cannon, and the 7.7 mm gun on the left side of the cowl was deleted. Four racks for rockets or small bombs were installed outboard of the 13 mm gun in each wing. Engine changed to a Nakajima NK1F “Sakae21” although some sources state that the A6M5c had a more powerful “Sakae 31” engine. In addition, a 55 mm thick piece of armored glass was installed at the headrest and an 8 mm thick plate of armor was installed behind the seat. The mounting of the central 300 l (79 US gal) drop tank changed to a four-post design. Wing skin was thickened further. The first of this variant was completed in September 1944 (Ref.: 24).

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

TYPE: Submarine-launched attack floatplane

ACCOMMODATION: Crew of two

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

ACCOMMODATION: Pilot only

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

ACCOMMODATION: Pilot only

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

ACCOMMODATION: Crew of two

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).