Nakajima B5N

https://en.wikipedia.org/wiki/Nakajima_B5N

The Nakajima B5N (Japanese: ?? B5N, Allied reporting name "Kate") was the
standard carrier-based torpedo bomber of the Imperial Japanese Navy (IJN) for
much of World War II.

Although the B5N was substantially faster and more capable than its Allied
counterparts, the American Douglas TBD Devastator monoplane (the U.S. Navy's
first all-metal, carrier-borne monoplane of any type with retracting gear), and
the British Fairey Swordfish and Fairey 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, the B6N. In the
early part of the Pacific War, flown by well-trained IJN aircrews and as part of
well-coordinated attacks, the B5N achieved particular successes at the battles
of Pearl Harbor, Coral Sea, Midway, and Santa Cruz Islands.

Primarily a carrier-based aircraft, it was also occasionally used as a
land-based bomber. The B5N carried a crew of three: pilot,
navigator/bombardier/observer, and radio operator/gunner.

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 the Yokosuka B4Y.
Internally designated Type K by Nakajima, it successfully competed with the
Mitsubishi B5M for a production contract. The first prototype flew in January
1937 and was ordered into production soon afterwards with the full designation
Type 97 Carrier Attack Bomber (kyu-nana-shiki kanjo kogeki-ki or kanko for
short.


Role
Carrier-based torpedo bomber

National origin
Japan

Manufacturer
Nakajima Aircraft Company

First flight
1937

Retired
1945

Primary user
Imperial Japanese Navy

Number built
1,149

The B5N soon saw combat, first in the Sino-Japanese War, where combat experience
revealed several weaknesses in the original B5N1 production model. These were
mainly concerned with the lack of protection that the design offered its crew
and its fuel 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 enemy
fighters. The B5N2 was given a much more powerful engine - Nakajima's own Sakae
Model 11, 14-cylinder twin-row radial, as used in the initial models of the
Mitsubishi A6M fighter — and various modifications were made to streamline it.
Although its performance was only marginally better, and its weaknesses remained
un-remedied, this version replaced the B5N1 in production and service from 1939.

It was this version that would be used by the Navy in the attack on Pearl
Harbor. The B5N2 Kate carried Mitsuo Fuchida, the commander of the attack, with
one from the carrier Hiryu credited with sinking the battleship Arizona. 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 the
United States Navy aircraft carriers Lexington and Hornet, and the disabling of
the Yorktown, which led to its sinking by the Japanese submarine I-168.

The B5N served as the basis for a follow-on design, the B6N, which eventually
replaced it in front line service. The B5N continued to fly in secondary roles,
such as training, target towing, and anti-submarine warfare. Some of the
aircraft used for this latter purpose were equipped with early radars and
magnetic anomaly detectors. B5Ns were also used as bombers during the
unsuccessful defence of the Philippines in October 1944, suffering severe
losses. Later in the war, they were also used for kamikaze attacks.

Specifications (Nakajima B5N2)

General characteristics
Crew: 3
Length: 10.3 m (33 ft 10 in)
Wingspan: 15.518 m (50 ft 11 in)
Wing area: 37.7 m2 (406 sq ft)
Airfoil: root: NN-5 mod (16%) ; tip: NN-5 mod (8%)
Empty weight: 2,279 kg (5,024 lb)
Gross weight: 3,800 kg (8,378 lb)
Max takeoff weight: 4,100 kg (9,039 lb)
Powerplant: 1 × Nakajima Sakae 11 14-cylinder air-cooled radial piston engine,
750 kW (1,000 hp) for take-off
720 kW (970 hp) at 3,000 m (9,843 ft)Propellers: 3-bladed constant-speed metal
propeller

Performance
Maximum speed: 378 km/h (235 mph, 204 kn) at 3,600 m (11,811 ft)
Cruise speed: 259 km/h (161 mph, 140 kn) at 3,000 m (9,843 ft)
Range: 978 km (608 mi, 528 nmi)
Ferry range: 1,991 km (1,237 mi, 1,075 nmi)
Service ceiling: 8,260 m (27,100 ft)
Rate of climb: 6.5 m/s (1,280 ft/min)
Time to altitude: 3,000 m (9,843 ft) in 7 minutes 40 seconds
Wing loading: 100.8 kg/m2 (20.6 lb/sq ft)
Power/mass: 0.196 kW/kg (0.119 hp/lb)

Armament

Guns: 1 × 7.7 mm Type 92 machine gun 'Ru' (Lewis) in rear dorsal position, fed
by hand loaded drum magazines of 97 rounds. A number of B5N1s were equipped with
2 × 7.7 Type 97 machine guns in the wings.
Bombs: 1 × 800 kg (1,760 lb) type 91 torpedo or 1 × 800kg (1,760lb) bomb or 2 ×
250 kg (550 lb) bombs or 6 × 60 kg (132 lb) bombs




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