WORLD WAR TWO RAIDEN

ALTHOUGH TROUBLESOME AND MAKING LITTLE IMPACT ON THE JAPANESE WAR EFFORT, THE PORTLY MITSUBISHI J2M3 RAIDEN STILL PROVED A WORTHY DESIGN, AS BARRY WHEELER EXPLAINS

Below ewey Boulevard, now Roxas FAVOURABLE RESULTS Manila, where it was reassembled, A J2M3 Raiden of the Blvd in the Philippines’ The Raidens belonged to the 381st the green paint removed and - - 302nd Ko ku tai scrambles capital Manila, runs for Kōkūtai (Naval Air Group) and prominent USAAF markings from Yokosuka, central D Japan, to intercept more than a mile alongside the shared the bizarre ‘dispersal’ with applied over its natural metal finish. a US stream blue waters of its bay. In February several Mitsubishi A6M5 Zero- Just two flights totalling 3hrs towards the end of the 1945, the US Army arrived at its Sen fighters of the 252nd Kōkūtai. 20mins were undertaken, but the war. On December 3 the former embassy on Dewey under Having been forced to leave their experienced US evaluation pilot type contributed to the the echoes of General MacArthur’s base at Nichols Field by heavy US was unhesitant in his opinion downing of six B-29s. ALL promise: “I shall return!” following bombing, the units moved north that the Raiden was a far better VIA BARRY WHEELER UNLESS STATED the Americans’ hasty withdrawal in to start flying missions from the machine than other Japanese fighters 1942. Not only did they find the arrow-straight boulevard in a last- such as the Zeke , Oscar , Nick or residence, which had been taken ditch attempt to defend Manila. Frank . It was considered to have over by the Nipponese military, Following the discovery, an ATAIU a satisfactory cockpit layout and intact, but also a rather motley photographer was summoned to with the help of the bulged canopy collection of Japanese Naval Air record the first close-up pictures of fitted to this later version, visibility Force (JNAF) aircraft parked under the coveted machines, numbered on the ground was passable while the tropical palms. Among them 3008 and 3013. Meanwhile, taxiing, and good when flying. The were two of the latest Mitsubishi a maintenance crew was also take-off run was short, with the J2M3 Raiden (Thunderbolt) dispatched to assess and disassemble aircraft leaving the ground readily fighters. Given the Allied codename the better of the two airframes for at 100mph (161km/h) and having Jack , the type was high on the possible flight testing; 3008 was little tendency to swing. Due to priority list for assessment by the chosen. Moved by low-loader, the the aircraft’s engine being relatively Allied Technical Air Intelligence war prize was transported to Clark new, its maximum performance in Unit (ATAIU). Field, 50 miles (81km) northeast of certain regimes was not attempted.

72 FLYPAST July 2019 However, it was noted that its climb appraised as superior to those on occupying most of the company, Above angle and speed were steep and fast. allied aircraft. it was three years before the first A cutaway produced Handling and control were Despite its many positives, the prototype J2M1 took to the air. It by the Technical Air considered respectable, although Jack had some weaker points – the showed none of the attractive lines Intelligence Center at Naval Air Station the ailerons were heavy at cruising aforementioned heavy ailerons, a of its predecessor. Its short, stubby Anacostia, Washington speed and even heavier at 325mph. lack of manoeuvrability at high wings incorporated a laminar-flow DC, following the ‘Hands-off’ at 8,500ft and 210mph, speed, short range and poor aerofoil section while its markedly discovery of two J2M3 the Raiden was a relatively stable mechanical reliability. The latter wide fuselage housed a 1,460hp Raidens in Manila during machine. The elevator trim tab was was proven when 3008 suffered (1,089kW) 13 February 1945. Unknown considered adequate, however, this a substantial oil leak during its engine within a closely cowled to the Allies, the type was fi tted with buoyancy worked in reverse to Allied types, so second evaluation flight at 16,000ft, nose, driving a three-bladed VDM tanks to keep it afl oat in rolling the wheel backwards made necessitating a dead-stick landing. propeller. Armament comprised two the event of ditching. the aircraft nose heavy. It didn’t fly again. 7.7mm Type 97 machine guns in The Raiden’s stalling characteristics the upper fuselage and two wing- were found to be excellent, with NEEDED IMPROVEMENT mounted 20mm . no tendency to spin, and in a In October 1938 the JNAF issued The first flight took place on clean configuration the nose or a a requirement for a new interceptor March 20, 1942 with company test wing dropped at around 100mph. to operate from both carriers and pilot Katsuzo Shima at the controls. Combat manoeuvring flaps were shore bases. The contract was given He noted the type was stable and fitted as standard and operated to Mitsubishi, with chief designer responsive to fly, but forward by a trigger switch on the control Jiro Horikoshi heading the team. visibility was inadequate due to column. Maximum speed for their However, with updates to the the curved windscreen. Needing use was 320mph and they were engineer’s famous A6M Zero-Sen more power to meet the navy’s

July 2019 FLYPAST 73 WORLD WAR TWO MITSUBISHI RAIDEN

Above Operated by the 381st Ko -ku-tai, Mitsubishi J2M3 Raiden 3008 was found alongside another example and several 252nd Ko -ku-tai ‘Zero’ fi ghters. Sustained US bombing had forced the units to operate from the road outside the embassy in a last-ditch attempt to defend Manila.

Right Following the discovery of the Raidens, 3008 was selected by the Allied Technical Air Intelligence Unit for evaluation. It is seen here wearing USAAF 375mph at 19,700ft specification, had a stronger wing; the armament markings, awaiting its and the ability to reach that height changed to four cannon and the fi rst test fl ight in US in 5mins 30secs, a 1,820hp Kasei fuselage guns were deleted. This hands from Clark Field, 23a powerplant was fitted to the became the standard production northeast of Manila. fourth prototype, while the canopy aircraft with 260 being produced Above centre right was raised and modified with by the end of the war – a far cry Two fl ights to assess the optically flat panels. The airscrew from the 3,600 the navy wanted type were undertaken was also changed to a four-bladed during 1944 alone. The J2M4 before a technical ‘snag’ type and with other adjustments, the Model 24 was a further upgrade, grounded it. Note the navy accepted the type as the J2M2 incorporating a turbo-supercharged previously forward-raked radio mast has been Raiden II in October. Kasei 23c engine, which produced replaced by a US example. Unexpected problems are never a top speed of 362mph (582km/h) far away with new aircraft, and the at 30,000ft. With two oblique- Right Raiden was certainly no exception. firing 20mm cannon added to the JACK’S CRUSADE Discovered after the war, An undercarriage fault led to the fuselage, this would have proved a The Raiden’s combat debut came this Raiden featured three loss of the second production potent adversary for the US Boeing towards the end of 1943 when a rear-fi ring 20mm cannon in the belly to allow the example on June 16, 1943 and in B-29 Superfortress crews. However, small number were assigned to 602 attacker to continue fi ring January 1944 the 30th example the was problematic Hikōtai of Air Group 381, to provide once it had passed the disintegrated over Toyohashi and led to just two aircraft being air defence over the Balikpapan target. It is not known airfield, east of Hamamatsu, completed. The fastest version was oil fields on the island of Borneo. if the modifi cation was following a firing pass. It is thought the supercharged J2M5 Model 33, However, by February 1944 just ten evaluated in combat. that vibration was the likely cause, which reached 382mph at 22,310ft had been delivered with very little with an engine panel coming loose and had a climb performance of chance of further airframes arriving. and hitting the tail assembly. 26,250ft in 9min 45sec. But by then When first encountered by the Modifications were made, but it was all too late, and just 34 were Allies it was believed to be an army- problems continued to plague produced, taking Raiden production operated aircraft. As it turned out, the type. Mitsubishi attempted to a modest 476 including 21 J2M3s the Raiden’s main role was to defend to resolve the difficulties with the with underwing gun packs, and one the home islands and in March improved J2M3 Model 21, which J2M6 with further airframe changes. 1944, 14 examples arrived with the

74 FLYPAST July 2019 the victor, however, was a Zero. early results of their raids. The first Above left According to surviving records, the large nocturnal raid on June 14, Two long-barrelled group was “singularly unlucky and against a steel works in Kyushu was 20mm Type 99 cannon were fi tted to ensure an achieved little success against the almost a complete failure due to accurate impression of US ”. Formed at the same poor accuracy. Utilising 68 bombers the type’s performance. time, Air Group 352 was assigned flying from Chengdu in South The Raiden was rather both day and night operations in the Central China, six aircraft were lost squat compared with its Sasebo, Nagasaki and Ōmura areas in accidents and one was shot down. Zero predecessor. with a similar mix of types. When A switch to high-altitude precision Above the Zeros and Gekkos flew the first bombing in early 1945 was trialled Lt Goro Ichimura of the missions on August 20, the unit was with a reduced bomb load, but the 302nd Ko -ku-tai in front still waiting for its J2M3s. However, B-29s suffered from overheating of his Raiden sometime 13 are recorded as flying a daylight engines during the long struggle in 1944. He later fl ew mission on October 25. to gain height. Accuracy was even the -J Raiden numbers also increased as more negligible. Then, in February, Shiden with success. the bombing of Japan intensified the pugnacious Maj Gen Curtis Below during spring 1945, but the type LeMay ordered the fire-bombing This ex-381st Ko -ku-tai Yokosuka Naval Air Group tasked continued to be beleaguered by of Japanese cities at night from low J2M3 Raiden wears the with covering Tokyo. Meanwhile, Air technical problems. A typical level. The first attack against Tokyo hastily applied acronym Group 302 was formed at Kisarazu example was Air Group 352 in overnight on March 9-10 produced of the Allied Technical on the east bank of Tokyo Bay before May 1945. Comprising 28 Zeros the results desired by LeMay – the Air Intelligence Unit South East Asia. moving to Atsugi Air Base (AB) with and 12 Gekkos, more than 75% of largely wooden city was incinerated. ANDY HAY/FLYING ART 48 Raidens. By February 1945, that these were operational, yet of the Minimal night-fighter opposition number had fallen to 31. 25 Raidens on strength, 20 were enabled the bombers to be stripped In August 1944, Air Group 332 grounded. Most of the issues often of most of their defensive armament. began a short period of defending centred on the type’s problematic While Japanese pilots were the Kure area from Iwakuni AB, Kasei powerplant. generally critical of the Raiden being southeast of Hiroshima, with its a heavy, un-manoeuvrable ‘beast’ initial complement of two Raidens, ‘SUPERFORT’ NEMESIS with a high landing speed and an 12 Nakajima J1N Gekko twin- For US B-29 crews flying with oversized cowling, engined night-fighters and 45 the Twentieth and Twenty- ‘Zeros’. By November, only 15 Second Air Forces, Japanese J2M3s had been delivered. The air defence over their following month, the unit archipelago was mixed, as transferred to Kobe where was the it scored its first ‘kill’…

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Above several pilots achieved notable on their way home. Standing patrols Raidens abandoned at Atsugi, A partially cowled J2M3 combat success over the Nipponese were ordered to counter this, but while numerous other airframes Raiden shows how the chain. On December 3, the type guessing which target was next were found dumped at different Kasai 23a engine fi tted into the fi ghter’s tapered contributed to shooting down six often meant the defending fighters locations. One curiosity was an fuselage. The aircraft was B-29s intercepted by a mixed group were low on fuel when they found aircraft modified for three ventral one of the few Japanese of Zeros and Raidens over Kyushu. them. This resulted in one, maybe rear-facing 20mm cannon beneath fi ghters equipped with a During other raids, numerous US two, short, sharp passes through the the fuselage to ‘spray’ the target supercharger, but it often bombers experienced ramming formations before landing with near after the attacker had passed. proved problematic both attacks by desperate naval aviators. empty tanks. Following the B-29’s Having already test-flown the type during trials and in service. Lieutenant (junior grade) Teimei switch to low-level night strikes, early in 1945, further technical Akamatsu of Air Group 302 proved Raidens and Zeros were left to tangle assessment by the ATAIU was not a Above right one of the few successful exponents with allied fighters until the atomic priority and four J2M3 Raiden 31s The Planes of Fame of the Raiden, and gained a small bombs were dropped on Hiroshima and four J3M5 Raiden 33s were Museum’s J2M3 is the number of victories over the North and Nagasaki in 1945. transferred to the US. Of these, just sole surviving example of the type, and is American P-51 Mustang and equally one survived large-scale scrapping seen here having been formidable . SAYONARA of Axis aircraft during the latter half restored for display. The Intercepting the massed raids, the In a little over a year, the XX and of the 1940s. This is now preserved aircraft was fi nished with Japanese defenders struggled to reach XXI Bomber Commands of the at the Planes of Fame Museum in yellow thunderbolts in the bombers at 30,000ft – let alone USAAF lost 414 B-29s over Japan, Chino, California. a salute to the type’s attack them. When they managed although some military sources say The Allied Technical Air translated name. the task, the raiders were normally this figure is nearer 450. Records Intelligence Unit, South East Asia, indicate 74 fell to fighters, a further was formed at Calcutta in 1943 MITSUBISHI J2M3 19 to a combination of air combat and towards the end of 1945, and anti-aircraft fire and more than the RAF assembled a collection MODEL 21 RAIDEN DATA 50 to flak alone. Others succumbed of captured Japanese aircraft at Type Single-seat naval fi ghter to weather and mechanical failures, Tebrau, across the Johore Straits (Allied reporting name Jack) the majority involving the Wright from Singapore. Among them were Crew 1 R-3350 engine which had a two J2M Raidens, coded BI-01 Powerplant One 1,820hp (1,357kW) Mitsubishi MK4B-A propensity to burst into flames. and 02. Flown briefly by vetted Kasei 23a With the Japanese surrender, Japanese pilots, the two aircraft American units discovered several were eventually scrapped. Length 32ft 7in (9.9m) Height 12ft 11in (3.9m) Wingspan 35ft 5in (10.7m) Gross wing area 216sq ft (20m 2) Empty weight 5,422lb (2,459kg) Max take-off weight 8,700lb (3,946kg) This J2M3 Raiden was one a pair found abandoned PERFORMANCE outside the former US Embassy in Manila, Max speed 365mph (587km/h) at 17,380ft (5,297m) Philippines, in February 1945 – minus its propeller Range 655 miles (1,054km) with 36 imp gal and armament. (164 lit) drop tank Ceiling 38,385ft Armament 2 x Type 99-2 inboard wing-mounted cannon, 2 x Type 99-1 outboard wing- mounted cannon, 2 x 132lb (60kg) bombs or 2 x 44 imp gal (200 lit) drop tanks or one single larger central drop tank

JNAF Raiden Units: Tainan Air Group, Yokosuka Air Group, Air Groups 95, 256 301, 302, 332 and 352, 602 Hiko-tai of Air Group 381

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