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).
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)