Unusual features in the basic design were a tiny laminar-flow wing fitted with combat flaps, a finely streamlined engine with propeller extension shaft and fan cooling, a very shallow enclosed canopy, and a surprising number of forged parts in the stressed-skin airframe.
The prototype Mitsubishi M-20, powered by a 1,460 hp Kasei, gave a great deal of trouble, with the result that the aircraft was largely redesigned as the J2M2, with a different engine, much deeper canopy, multi-stack exhaust and a new four-blade propeller. Even then the Raiden suffered repeated faults and several crashes, but eventually 155 of the J2M2 were delivered with two 20mm Type 99 cannon and two 7.7mm machine-guns.
Production then switched to the J2M3, in which the machine-guns were removed and four cannon mounted in the wings.
A few high-altitude J2M4 turbocharged versions were built, armed with six cannon, the two additional guns being mounted in the top fuselage decking.
The most effective version was the J2M5. This variant only carried two 20mm cannon (in the wings) but was powered by a far better engine, and it proved formidable against raiding B-29s. Nonetheless Mitsubishi had only built 450 Raidens, of all variants, by the time the war ended.
Data
(Raiden
J2M2)
Origin: Mitsubishi Jukogyo KK
Type: Single-seat land-based interceptor fighter
Dimensions: Span 35' 5" (10.8 metres) Length 31' 10" (9.7 metres) Height 12' 6" (3.81 metres)
Weights (J2M2): Empty 5,572 lb (2,527 kg) Loaded 7,257 lb (3,300 kg)
Engine: One 1,820 hp Mitsubishi MK4R-A Kasei 23a 14-cylinder two-row radial
Armament: see text
Maximum speed (J2M2): 371 mph (596 km/hour)
Initial Climb: 3,610 feet (1,100 metres) per minute
Range : (at normal loaded weight)
655 miles (1,055 km)
Pacific
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