Enter the Raiden!
Mitsubishi J2M Raiden on display at the Chino Planes of Fame museum in California, USA.
Welcome back to Brooke In The Air! Today we’re going over the fighter that could have potentially won the war for Japan if it wasn't too late.
Let’s dive in!
INTRODUCTION
The Mitsubishi J2M Raiden (雷電, "Lightning Bolt") is a single-engined land-based fighter aircraft used by the Imperial Japanese Navy Air Service in World War II. The Allied reporting name was “Jack.”
The J2M was designed by Engineer Jiro Horikoshi, creator of the Mitsubishi A6M Zero, to meet the 14-Shi (14th year of the Showa reign, or 1939 in the Western calendar) official specification.
For all purposes, it was 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 manoeuvrability.
DEVELOPMENT
The J2M was a sleek, but stubby craft with its oversized Mitsubishi Kasei engine buried behind a long cowling, cooled by an intake fan and connected to the propeller with an extension shaft.
Surviving photo of the J2M2 on the flightline, 1944.
Teething development problems stemming from the engine cooling system, and the main undercarriage members led to a slowdown in production. A continual set of modifications resulted in new variants being introduced with the ultimate high-altitude variant, the J2M4 Model 34 flying for the first time in August 1944.
It had a 1,420 hp Kasei 23c engine equipped with a turbocharger (mounted in the side of the fuselage just behind the engine) that allowed the rated power to be maintained up to 9,100 m (29,900 ft). Two upward-aimed, oblique-firing (aimed at seventy degrees) 20 mm cannons, mounted in the German Schräge Musik style, were fitted behind the cockpit with the four wing cannons retained. Unresolved difficulties with the turbocharger caused the project to be terminated after only two experimental J2M4s were built.
OPERATIONS
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 Model 11 was delivered to 381st Kōkūtai in December 1943. Parallel with the J2M2, production of the J2M3 Raiden Model 21 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 the Philippine Sea. Several J2Ms operated from Guam and Saipan and a small number of aircraft were deployed to the Philippines.
The Raiden made its combat debut in June 1944 during the Battle of the Philippine Sea, AKA The Great Marianas Turkey Shoot. Several J2Ms operated from Guam and Saipan and a small number of aircraft were deployed to the Philippines. Later, some J2Ms were based in Japanese airfields in Korea, for defense of these select areas km Korea and fighting against Soviet Naval Aviation units.
Primarily designed to defend against the Boeing B-29 Superfortress heavy bomber, the Raiden was handicapped at high altitude by the lack of a turbocharger. 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 llimited the Raiden's effectiveness.
J2Ms took part in one of the final aerial combats of the Second World War when four Raidens, accompanied by eight Mitsubishi A6M Zeros, all belonging to the 302nd Kokutai, intercepted a formation of US Navy Grumman F6F Hellcats from the aircraft-carrier USS Yorktown during the morning of 15 August 1945 over the Kanto Plain. In the engagement, that took place only two hours before Japan officially announced its surrender, four Hellcats were lost along with two Raidens and two Zeros.
U.S. Technical Air Intelligence Command (TAIC) tested two captured J2Ms using 92 octane fuel plus methanol and calculated maximum speeds using measurements. The J2M2 ("Jack 11") achieved a theoretical top speed of 407 mph (655 km/h) at 17,400 ft (5,300 m), and the J2M3 ("Jack 21") achieved a theoretical top speed of 671 km/h (417 mph) at 4,980 m (16,600 ft).
J2M2 being tested by captured pilots by the RAF.
VARIANTS
J2M1 Prototype: fitted with the 1,044 kW (1,400 hp) Mitsubishi MK4C Kasei 13 14-cylinder air-cooled radial engine, and armed with two 7.7 mm (.303 in) Type 97 machine guns in the upper fuselage and two wing-mounted 20 mm Type 99 Model II cannon. - Eight built.
J2M2 Model 11: Powered by 1,379 kW (1,850 hp) Mitsubishi MK4R-A Kasei 23a 14-cylinder radial engine, same armament as the J2M1. Minor engine improvements only.
J2M3 Model 21: Armed with two wing-mounted 20 mm Type 99 Model II cannon and two wing-mounted 20 mm Type 99 Model I cannon. Secondary variant.
J2M3a Model 21A: Armed with four wing-mounted 20 mm Type 99 Model II cannon. Very limited number.
J2M4 Model 32: Final prototype model, fitted with the 1,357 kW (1,820 hp) Mitsubishi MK4R-C Kasei 23c engine. Many armament configurations have been reported, e.g., fuselage-mounted oblique-firing 20 mm Type 99 Model I cannon designed to fire upward as it passed underneath a bomber, two wing-mounted 20 mm Type 99 Model II cannon, and two wing-mounted 20 mm Type 99 Model I cannon. Problems with turbocharger; only two experimental versions were built by war’s end, tested by the Allies.
J2M5 Model 33: High altitude variant powered by 1,357 kW (1,820 hp) Mitsubishi MK4U-A Kasei 26a engine with mechanically driven supercharger, giving increased high-altitude speed at the expense of range. Two 20 mm Type 99 cannon in fuselage, two 20 mm Type 99 Model II cannon in wings.
J2M5a Model 33A: Armed with four wing-mounted 20 mm Type 99 Model II cannon. Wing cannon were harmonized in trajectory and ballistics with each having 200 rounds per gun, designed with endurance in mind.
J2M6 Model 31: Chronologically earlier than J2M4 and J2M5 this version was based on J2M3. Had wider cockpit and improved bubble canopy later used in J2M3. Final version built in July of 1943.
J2M6a Model 31A: Chronologically earlier than J2M4 and J2M5 this version was based on J2M3a. Thid version had a wider cockpit and improved bubble canopy later used in J2M3a built since July 1943. One J2M6a was built, scrapped by the Allies on general MacArthur's orders.
J2M7 Model 23A: J2M3 powered by Kasei 26a engine, only a few ever built.
TRAGEDY
After the decisive Battle of Midway in 1942 Japan's military leaders rushed to re-equip their forces for defense of the home islands. In fighter designs the interceptor role now took priority over forward projection of offensive power. Six months after Pearl Harbor, the IJN was already readying for defeat. The Raiden was part of that readiness plan.
Allied forces, meanwhile, sought to establish air superiority over Japanese-held island territories via B-29 bombing raids on industrial targets.
The struggle to meet production demands sparked a Japanese initiative to recruit shonenko (child labour) from Taiwan (then-known as Formosa). Though the target of 25,000 youths was never reached, over 8,400 Taiwanese youths aged 12 to 14 relocated to Mitsubishi plants to help build the J2M Raiden.
The Allied advance subsequently took its toll.
In 1945, aircraft production in Japan collapsed, as numbers for the J2M Raiden thus reflect.
Allied bombing raids of Nagoya began in December 1944 and progressively disrupted production of the J2M. Ultimately, a direct hit on the Mitsubishi Dai San Kokuki Seisakusho aircraft plant caused the complete loss of airframes, machine tools, and jigs. This halted all further production until the end of the war.
The Raiden could potentially have won the war if circumstances had differed but they didn’t. Things only got worse for Japan after the death of Admiral Isoroku Yamamoto in 1943 in Operation Vengeance. The J2M was too little, too late.
SURVIVING EXAMPLE
The J2M3 Model 21 c/n 3014 is on display at the Planes of Fame museum in Chino, California, USA. This is the only Raiden still in serviceable condition in the world.
SPECIFICATIONS
Crew: 1
Length: 9.945 m (32 ft 8 in)
Wingspan: 10.8 m (35 ft 5 in)
Height: 3.81 m (12 ft 6 in)
Wing area: 20.05 m2 (215.8 sq ft)
Empty weight: 2,839 kg (6,259 lb)
Gross weight: 3,211 kg (7,079 lb)
Powerplant: 1 × Mitsubishi MK4R-A Kasei 23a 14-cylinder air-cooled radial piston engine, 1,300 kW (1,800 hp) for take-off
— 1,174 kW (1,575 hp) at 1,800 m (5,900 ft)
— 1,051 kW (1,410 hp) at 4,800 m (15,700 ft)
Propellers: 4-bladed constant-speed metal propeller
Maximum speed: 587 km/h (365 mph, 317 kn) at 5,300 m (17,400 ft)
Cruise speed: 351 km/h (218 mph, 190 kn)
Range: 1,898 km (1,179 mi, 1,025 nmi)
Service ceiling: 11,700 m (38,400 ft)
Time to altitude: 6,000 m (20,000 ft) in 6 minutes 14 seconds
Power/mass: 0.391 kW/kg (0.238 hp/lb)
Armament
2x 20 mm (0.787 in) Type 99 Mark 2 machine gun inboard wing-mounted with 190 rpg
2x Type 99 Mark 1 machine gun outboard wing-mounted with 210 rpg
2× 60 kg (132 lb) bombs
or
2 × 200 L (53 US gal; 44 imp gal) drop tanks or a larger central drop tank
