POWER PLANT: One Nakajima NK9H “Homare” 42 radial engine, rated at 2,000 hp
PERFORMANCE: 426 mph at 32,810 ft
COMMENT: The Kawanishi J6K1 “Jinpu”was a purpose-built land based interceptor designed for the Imperial Japanese Navy Air Force, but that didn’t enter production because of the success of the same company’s Kawanishi N1K2-J “Shiden” (“Violet lightning”, Allied code “George”).
The J6K1 was developed from the Kawanishi J3K1 of 1942. This was to have been powered by the Mitsubishi MK9A radial engine, and would have been a fairly standard looking radial engined fighter, but it didn’t progress beyond the early design stage.
Work on the J6K1 began in 1943. This time the aircraft was to use the Nakajima “Homare” 42 engine, the design progressed far enough to receive a popular name, the “Jinpu”(Squall). The new interceptor would have been very heavily armed, with two 30mm cannon and two 13.2mm machine guns, and with a good top speed of 426mph. The J6K1 never entered production. Kawanishi had also produced the N1K1 Kyofu” (“Mighty wind, Allied code “Rex”) float plane fighter, which was followed by a normal landed based version, the N1K1. This was then superseded by the N1K2-J “Shiden”, a smaller aircraft than the J6K, armed with four 20mm cannon and with sufficiently impressive performance to meet the Navy’s requirements. The N1K2-J was produced in large numbers, while the J6K1 was cancelled (Ref.: 24).
POWER PLANT: One Ishikawajima Ne-130 turbojet engine, rated at 900 kp thrust
PERFORMANCE: No data available
COMMENT: The concept of Kyushu J7W1 unique canard configuration was due to designers of the Technical staff of the Japanese Navy. From the onset of that project it was envisaged to replace the rear-mounted Mitsubishi Ha-43 air-cooled radial engine, which drove a six-blade pusher propeller, with the new turbojet engines under development at that time.
Following some initial work on that concept, the staff of Dai-Ichi Kaigun Koku Gijitsusho (First Naval Air Technical Arsenal) designed a glider to test the aircraft’s handling qualities at low speeds. Three prototypes of the MXY6 were built for the Navy by Chigasaki Seizo K.K. and these all-wood gliders with moderately swept wings supporting tall tail surfaces inboard the ailerons began flight trials in autumn of 1943.
Although the “Shinden” was expected to be a highly maneuverable interceptor, only two prototypes were finished before the end of war. And of course the turbojet engine powered Kyushu J7W2 was never realized, it didn’t even reach the drawing board (Ref.: 24).
POWER PLANT: One Mitsubishi Ha-43 12 (MK9D) radial engine, rated at 2,130 hp
PERFORMANCE: 469 mph
COMMENT: The Kyūshū J7W1 “Shinden”( “Magnificent Lightning”) fighter was a Japanese propeller-driven aircraft prototype with wings at the rear of the fuselage, a nose mounted canard, and pusher engine. Developed by the Imperial Japanese Navy (IJN) as a short-range, land-based interceptor, the J7W was a response to Boeing B-29 “Superfortress” raids on the Japanese home islands. In the IJN designation system, “J” referred to land-based fighters and “W” to Watanabe Tekkōjo, the company that oversaw the initial design..
The construction of the first two prototypes started in earnest by June 1944, and the first prototype was completed in April 1945. The 2,130 hp Mitsubishi MK9D (Ha-43) radial engine and its supercharger were installed behind the cockpit and drove a six-bladed propeller via an extension shaft. Engine cooling was to be provided by long, narrow, obliquely mounted intakes on the side of the fuselage. It was this configuration that caused cooling problems while running the engine while it was still on the ground. This, together with the unavailability of some equipment parts postponed the first flight of the “Shinden”. Even before the first prototype took to the air, the Navy ordered the J7W1 into production, with a quota of 30 “Shinden” a month given to Kyushu’s Zasshonokuma factory and 120 from Nakajima’s Handa plant. It was estimated some 1,086 “Shinden” could be produced between April 1946 and March 1947.
On August 1945, the prototype first flew from Itazuke Air Base. Two more short flights were made, a total of 45 minutes airborne, one each on the same days as the atomic bombings of Hiroshima and Nagasaki occurred, before the war’s end. Flights were successful, but showed a marked torque pull to starboard (due to the powerful engine), some flutter of the propeller blades, and vibration in the extended drive shaft.
A turbojet engine–powered version, the Kyushu J7K2, was considered, but never even reached the drawing board (Ref.: 24).
POWER PLANT: Two Ishikawajima Ne-20 turbojet engines, rated at 475 kp each
PERFORMANCE: 433 mph at 32,800 ft (estimated)
COMMENT: Design work on the Nakajima “Kikka” – the only Japanese turbojet powered aircraft capable of taking-off on its own power, albeit only twice during World War II – began in September 1944. The enthusiastic reports on the progress of the Messerschmitt Me 262 twin-jet fighter received from the Japanese Air Attaché in Germany had prompted the Naval Staff to instruct Nakajima to design a single-seat twin-jet attack fighter based on the German Me 262.
The aircraft externally resembled the Me 262 but was smaller. Two turbojets were mounted in separate nacelles under the wing to allow the installation of engines of various types. Provisions were made for folding wings, to enable the aircraft to be hidden in caves and tunnels and also for ease of production by semi-skilled labor. Initial plans to power the aircraft by two N-12 turbojet engines each delivering 340 kp thrust were refused due to insufficient thrust. Fortunately, photographs of the German BMW 003 axial-flow turbojet had been obtained and from these the Japanese were able to design a similar turbojet, designate Ne-20, offering a thrust of 475 kp. Completed in August 1945, the first “Kikka” made its maiden flight. Four days late the pilot aborted a take-off during the second flight, the accident being caused by mounting the two rocket-assisted-take-off (RATO) rockets at an incorrect angle. A second prototype (shown here) was almost ready for flight trials and eighteen additional prototypes and pre-production aircraft were ready in various stages of assembly when with the end of WW II the development of the aircraft was terminated (Ref.: 1).
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).
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.
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 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)