Category Archives: Imperial Navy Air Force

Japan

Mitsubishi J2M3 “Raiden” (“Thunderbolt”), (“Jack”), 302nd Kokutai

TYPE: Interceptor fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi MK4R-A Kasei 23a radial engine, rated at 1,800 hp

PERFORMANCE: 365 mph at 17,390 ft

COMMENT: The Mitsubishi J2M “Raiden” was a single-engine land-based fighter aircraft used by the Imperial Japanese Navy Air Force in World War II. The Allied reporting name was “Jack”. The J2M was designed to be a strictly local-defense interceptor, intended to counter the threat of high-altitude bomber raids, and thus relied on speed, climb performance, and armament at the expense of maneuverability. The J2M was a sleek, but stubby craft with its over-sized Mitsubishi Kasei engine buried behind a long cowling, cooled by an intake fan and connected to the propeller with an extension shaft.
Teething development problems stemming from the Kasei engine cooling system, and the main undercarriage members led to a slowdown in production.  The first few produced J2M2s were delivered to the development units in December 1942 but severe problems were encountered with the engines. Trials and improvements took almost a year and the first batch of the serial built J2M2 was delivered in December 1943. Parallel with the J2M2, production of the J2M3 “Raiden” started. The first J2M3s appeared in October 1943 but deliveries to combat units started at the beginning of February 1944.The “Raiden” made its combat debut in June 1944 during the Battle of Philippine Sea. Several J2Ms operated from Guam and Saipan and a small number of aircraft were deployed to the Philippines.
Primarily designed to defend against the Boeing B-29 “Superfortress”, the lack of a turbocharger handicapped the aircraft at high altitude. However, its four-cannon armament supplied effective firepower and the use of dive and zoom tactics allowed it to score occasionally. Insufficient numbers and the American switch to night bombing in March 1945 limited its effectiveness (Ref.: 24).

Mitsubishi G7M1 “Taizan” (Great Mountain), (Unicraft, Resin)

TYPE: Long-range bomber. Project

ACCOMMODATION: Crew of five

POWER PLANT: Two Mitsubishi Ha 42 twin-engines, rated at 2,400 hp each

PERFORMANCE: 346 mph

COMMENT: The Mitsubishi G7M was basically a derivative of the most famous Mitsubishi G4M Navy attack bomber. It was originally designed as a long range, strategic bomber able to carry a greater payload over a longer distance. To meet these requirements a four-engine design was favored.
When detailed information about the German Heinkel He 177 became available – a four-engine heavy bomber with dive-bombing capability, powered by two H-engines twinned together in one nacelle on each side thus reducing drag – the G7M design was changed in that manner. Germany promised to deliver the needed machinery to produce the H-engines under license. Other features of the Heinkel design were incorporated, too, such as the glazed nose, four-blade propellers, and a similar tail plane. In contrast the Mitsubishi design used a tricycle landing gear system. The ongoing war situation made it impossible to import the German H-engines as well as the tools for production and the design was changed again to a four-engine bomber but the end of the hostilities stopped all further work (Ref.: 24).

Mitsubishi J4M-2 Senden-Kai (Unicraft, Resin)

TYPE: Fighter. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Ishikawajima Ne-230 axial-flow turbojet engine, rated at 885 kp thrust

PERFORMANCE: Data not available

COMMENT: The availability of more sophisticated turbojet engines in the closing stage of the Pacific War brought the Japanese aircraft industry to plans to design completely new turbojet fighters, such as Nakajima Kikka, Nakajima Ki-201 Karyu (Fire Dragon), and Rikugun Ki-202,  or to provide newest piston engine designs with turbojets. Examples are the conversion of the Kyushu J7W1 Sinden (Magnificent Lightning) into the Kyushu J7W2 with one Ishikawajima Ne-130 turbojet engine, the Yokosuka R2Y1 Keiun (Beautiful Cloud) with two Ishikawajima Ne-330 turbo jet engines, and Mitsubishi J4M-1 Senden (Flashing Lightning). This twin-boom fighter project, powered by a Mitsubishi MK9D radial engine, driving a six-blade pusher propeller was redesigned to a much smaller aircraft, also in twin-boom configuration, but powered by one Ishikawajima Ne-230 axial-flow turbojet engine, that was expected to give 885 kp thrust. But the end of the hostilities brought all work on this Mitsubishi J4M-2 Senden-Kai project to a halt.

Mitsubishi J4M-1 Senden (Flashing Lightning, Luke), Unicraft, Resin

TYPE: High performance interceptor fighter. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Ha-43 radial engine, rated at 1,650 hp at 26,247 ft, driving 6-bladed metal constant speed pusher propeller

PERFORMANCE: 470 mph at 26,247 ft

COMMENT: To provide the Imperial Japanese Navy with a land-based high-performance interceptor aircraft, Mitsubishi designed the J4M Senden (“Flashing Lighting”) or Navy Experimental 17-Shi Otsu B Type Interceptor Fighter Senden. It was to have been a single-seat, twin-boom, low-wing monoplane with a central nacelle housing an unstepped cockpit and a 2,130-hp Mitsubishi MK9D (Ha-43) radial engine behind the pilot driving a six-bladed pusher propeller rotating between the booms. The booms were to extend aft from the leading edge of the wing and were mounted below the central nacelle. The aircraft was to have had tricycle landing gear and an armament of one 30-mm and two 20-mm cannon. Design of the initial J4M1 version ended when the Navy put its support behind the competing Kyushu J7W fighter. So the J4M project did not proceed beyond the design stage. The Allies nonetheless assigned the J4M the reporting name “Luke” during World War II.(Ref.: 23)

Kawanishi N1K1 “Kyofu” (“Mighty Wind”), 1st Prototype (Hasegawa)

TYPE: Float seaplane fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi MK4D “Kasei 14” radial engine, rated at 1,460 hp, driving contra-rotating two-blade propellers

PERFORMANCE: 300 mph at 17,650 ft

COMMENT: Appearing too late to serve in its intended role, the Kawanishi N1K1 “Kyofu (“Mighty Wind”) floatplane fighter participated only briefly in combat operations but it sound design led to its adaptation into one of the most successful land-based fighter aircraft of WW II, the Kawanishi N1K1-J “Shiden”.
Development of a series of floatplane fighters intended to provide air support to Japanese amphibious landing forces in areas where no airfield existed was initiated in 1940, while Nakajima Hikoki K.K. undertook the development of an interim aircraft – the A6M2-N – Kawanishi Kokuki K.K  were instructed to initiate the design of an aircraft specially conceived for that purpose. Issued by the Japanese Navy in September 1940 planning began immediately in the Kawanishi engineering office. Basing their efforts on the advanced technology developed for the Kawasnishi E15K1 “Shiun”, a team of engineers designed a compact floatplane with mid-mounted wings of laminar-flow section. Like the “Shiun”, the projected floatplane fighter, then known by the designation of K-20, was to be powered by a 1,460 hp Mitsubishi MK4D “Kasei 14” driving two contra-rotating two-blade propellers to offset the anticipated propeller torque on take-off. The central float was to be attached to the fuselage by a V-strut forward and an I-strut at the rear, but the proposed use of retractable stabilizing floats with metal planning bottom and inflatable rubberized-fabric tops could be traced to the “Shiun’s” design philosophy. Difficulties encountered with this type of float during the early part of E15K1 flight trial programme led to their replacement by fixed cantilever floats prior to the aircraft’s first flight.
Following the completion the first N1K1 made its successful maiden flight on 6 May, 1942. However, teething troubles with the contra-rotating propeller gear box – similar to those experienced in the E15K1 programme – led to the decision to replace the “Kasei 14” engine by a MK4C “Kasei 13” driving conventional three-blade propeller via an extension shaft. Once in the air the N1K1 was an extremely pleasant aircrafts to handle and the use of combat flaps gave it remarkable maneuverability. Finally, based on these good results the Japanese Navy ordered the aircraft into quantity production as the Navy Fighter Seaplane “Kyofu Model 11”, (Kawanishi N1K1 “Kyofu”) and deliveries of production aircraft began in spring 1943 (Ref.: 1).

Kawanishi N1K1 “Kyofu” (“Mighty Wind”, “Rex”) (Hasegawa)

TYPE: Float seaplane fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi MK4E “Kasi 14” radial engine, rated  at 1,400 hp

PERFORMANCE: 304 mph at 18,700 ft

COMMENT: Satisfied with the results of the flight trial progamme of the prototypes of the Kawanashi N1K1 the Imperial Japanese Navy ordered the aircraft into quantity production as the Navy Fighter Seaplane “Kyofu Model 11”, and deliveries of production aircraft began in spring of 1943 following the completion of eight prototypes and service trials aircraft. But production was slow in gaining tempo and by December 1943, when the delivery rate had reached fifteen aircraft per month, the decision was taken to cease manufacture of the “Kyofu” and the last N1K1 was delivered in March 1944. This decision did not indicate any misgiving on the aircraft’s capability but merely reflected the fact that the war had taken an unfavourable turn for Japan which no longer needed a fighter to support offensive operations.
The war situation was also reflected in the operational use of the aircraft in a defensive role and N1K1s (Allied code name “Rex”) were assigned as interceptors in the Borneo Area of Action. Late in the war the “Kyofu” was assigned to similar duties with the Otsu Kokutai operating from Lake Biwa as an air defence unit (Ref.: 1).