| B5N | |
|---|---|
 A Nakajima B5N2 in flight | |
| General information | |
| Type | Carrier-basedtorpedo bomber/high-level bomber |
| National origin | Japan |
| Manufacturer | Nakajima Aircraft Company |
| Status | Retired |
| Primary user | Imperial Japanese Navy Air Service |
| Number built | 1,149[1] |
| History | |
| First flight | January 1937 |
| Retired | 1945 |
| Developed into | Nakajima B6N Tenzan |
TheNakajima B5N (Allied reporting name "Kate") was the standardcarrier-basedtorpedo bomber of theImperial Japanese Navy (IJN) for much ofWorld War II. It also served as ahigh level bomber.
Although the B5N was substantially faster and more capable than its Allied counterparts, the AmericanDouglas TBD Devastator monoplane (the U.S. Navy's first all-metal, carrier-borne monoplane of any type with retracting gear), and the BritishFairey Swordfish andFairey Albacore torpedo biplanes, it was nearing obsolescence by 1941. Nevertheless, the B5N operated throughout the whole war, due to the delayed development of its successor, theB6NTenzan.
In the early part of thePacific War, when flown by well-trained IJN aircrews and as part of well-coordinated attacks, the B5N achieved particular successes at the battles ofPearl Harbor,Coral Sea,Midway, andSanta Cruz Islands.[2][3]
The B5N was designed by a team led by Katsuji Nakamura in response to a 1935 specification by the Navy for a torpedo bomber to replace theYokosuka B4Y. Internally designatedType K by Nakajima, it successfully competed with theMitsubishi B5M for a production contract. The firstprototype flew in January 1937 and was ordered into production soon afterwards with the full designationType 97 Carrier Attack Bomber[4] (九七式艦上攻撃機) (kyū-nana-shiki kanjō kōgeki-ki orkankō for short).[5]
Combat experience during theSecond Sino-Japanese War revealed several weaknesses in the originalB5N1 production model. These were mainly concerned with the lack of protection that the design offered its crew and itsfuel tanks. Keen to maintain the high performance of the type, the Navy was reluctant to add weight in the form of armor, and instead looked to obtaining a faster version of the aircraft in the hopes of outrunning enemyfighters. TheB5N2 was given a much more powerful engine - Nakajima's ownSakae Model 11, 14-cylinder twin-row radial, as used in the initial models of theMitsubishi A6M fighter – and various modifications were made to streamline it. Although its performance was only marginally better, and its weaknesses remained unremedied, this version replaced the B5N1 in production and service from 1939.
Thenavigator/bombardier/observer position was equipped with a Type 90bombsight, which was a long vertical tube located in the front-left of the seat. There was also a Type 3reflectorcompass for precise navigation that was mounted on the top of thecockpit frame. Theradio-operator/gunner position was equipped with one of the standard-issueradio sets for navy three-seater aircraft (Type 96 Mk3 earlier and Type 2 Mk3 later) that was mounted in front of the radio-operator/gunner's seat and behind the navigator/bombardier/observer's seat.[6][7]
The radio-operator/gunner also operated one flexible 7.7 mm (.303 in)Type 92 machine gun at the rear end of the cockpit. OneType 91 torpedo could be mounted on theracks that were fixed eccentrically to the right at the bottom of the fuselage. Alternatively, racks could be replaced to carry either one 800 kg bomb (e.g.,Type 99 No 80armor-piercing bomb) or two 250 kg bombs (e.g., Type 98 No 25 land bomb) or six 60 kg bombs (e.g., Type 2 No 6 land bomb). Replacing the racks and exchanging between the torpedo and bombs was not a trivial process and could take more than two hours to complete.[8]
Initially, most of the B5N bombers were painted in silver, which was the color used throughout the early stages of the Second Sino-Japanese War. The color eventually changed to dark green before the start of thePacific War.[9]
The B5N was primarily employed as a carrier-based aircraft and occasionally as a land-basedbomber. It carried a crew of three:pilot, navigator/bombardier/observer, and radio-operator/gunner.[10] As with other IJN multi-seat aircraft, an individual bomber was commanded by the senior ranking crew member aboard, which could be the observer rather than the pilot.[11]
The initial model B5N1 first saw action in the Second Sino-Japanese War in 1938. The updated B5N2 played a major role in theAttack on Pearl Harbor. One of the B5N2s carriedMitsuo Fuchida, the commander of the attack, with one high-level bomber from the carrierHiryū credited with sinking the American battleshipArizona. The B5N2 torpedo bombers also sank the battleshipsWest Virginia,California,Oklahoma andUtah. Five torpedo bombers were shot down in the first wave. Apart from this raid, the greatest successes of the B5N2 were the key roles it played in sinking theUnited States Navyaircraft carrierLexington at theBattle of the Coral Sea and the aircraft carrierHornet at theBattle of the Santa Cruz Islands, and the disabling of the aircraft carrierYorktown at theBattle of Midway, later sunk by theJapanese submarine I-168.[2][3]
B5N2 torpedo bombers normally performed a coordinated attack on enemy carriers withAichi D3A dive bombers. Ideally, dive bombers would help to suppress the ship'santi-aircraft fire, which improved the chances of success for the slow-flying torpedo bombers.[11] During theBattle of the Eastern Solomons, the IJN tried to minimize losses to torpedo bombers and initially sent only the dive bombers to attack and cripple US carriers for the subsequent torpedo strike, this proved unsuccessful, as the torpedo bombers did not launch until the battle was over.[12]
The B5N served as the basis for a follow-on design, theB6NTenzan, which eventually replaced it in front-line service. The B5N continued to fly in secondary roles, such astraining,target towing, andanti-submarine warfare. Some of the aircraft used for this latter purpose were equipped with earlyradars andmagnetic anomaly detectors. B5Ns were also used as bombers during the unsuccessful defense of the Philippines in October 1944, suffering severe losses. Later in the war, they were used forkamikaze attacks.
None of the 1,150 production B5Ns survived World War II intact. Only two partially-recovered B5Ns are known to exist, neither of them airworthy.
Replicas of the B5N2s were made using stretched fuselages from U.S. Canadian Car and Foundry "Harvard" - a variant of theNorth American T-6 Texan trainers, which were modified to represent Japanese aircraft for the movieTora! Tora! Tora!, and have been used in a number of movies and airshows since to depict the aircraft.
One recovered B5N2 is at theWings Museum in Balcombe, West Sussex, UK.[13] This large portion was recovered from theKuril Islands by a British private collector in 2003.[citation needed]
A B5N was unveiled at thePacific Aviation Museum inHonolulu, Hawaii on 18 April 2016.[14]
Data fromJapanese Aircraft of the Pacific War[15]
General characteristics
Performance
Armament
Aircraft of comparable role, configuration, and era
Related lists
