Nakajima B5N

Nakajima B5N
Name	Nakajima B5N
Type	Torpedo bomber
Manufacturer	Nakajima Aircraft Company
Designer	Katsuji Nakamura
First flight	January 1937
Introduced	1937
Retired	1945
Primary user	Imperial Japanese Navy Air Service
Number built	Approximately 1,150
Status	Retired

Nakajima B5N. The Nakajima B5N was the primary carrier-based torpedo bomber of the Imperial Japanese Navy Air Service for much of the Second Sino-Japanese War and the early years of World War II. Designed to a demanding 1935 specification, it outperformed its contemporaries and was known to the Allies by the reporting name Kate. Although obsolescent by 1942, it achieved lasting fame for its pivotal role in the attack on Pearl Harbor and other major naval battles in the Pacific War.

Development and design

The development of the aircraft was initiated by the Imperial Japanese Navy to replace the aging Yokosuka B4Y. A design team led by Katsuji Nakamura at the Nakajima Aircraft Company created a modern, all-metal monoplane with retractable landing gear and enclosed cockpits. The prototype, powered by the Nakajima Hikari radial engine, first flew in January 1937 and demonstrated superior performance over its competitors from Aichi Kokuki and Mitsubishi Heavy Industries. The design featured hydraulically operated flaps and a long ventral fuselage window for the bombardier, with the aircraft capable of carrying either one Type 91 torpedo or an equivalent bomb load. Despite its advanced design, defensive armament was limited to a single, manually operated 7.7mm machine gun in the rear cockpit, a significant weakness in later combat.

Operational history

The aircraft entered service in 1937 and saw initial combat in the Second Sino-Japanese War, performing effectively in the Battle of Wuhan and other engagements. Its most historically significant actions occurred during the opening stages of the Pacific War. As the main strike aircraft of the Kido Butai, it formed the core of the attack force at attack on Pearl Harbor, where it sank or damaged multiple battleships including the USS Arizona and USS Oklahoma. It continued to score major successes in subsequent naval battles, contributing to the sinkings of the USS Lexington at the Battle of the Coral Sea and the USS Hornet at the Battle of the Santa Cruz Islands. However, during the Battle of Midway, vulnerable formations suffered devastating losses to fighters from USS Enterprise and USS Yorktown. By 1943, its lack of speed, armor, and defensive firepower made it highly vulnerable to Allied fighters like the Grumman F4F Wildcat and it was gradually relegated to secondary duties, including anti-submarine patrols and kamikaze attacks during the later stages of the Battle of Okinawa.

Variants

The primary production model was the initial **B5N1**, which utilized the Nakajima Hikari engine. To improve performance, the **B5N2** model was introduced, featuring the more powerful Nakajima Sakae radial engine and a redesigned cowling; this became the definitive and most numerous version. A dedicated trainer version, the **B5N1-K**, was developed with dual controls. Several experimental variants were tested, including the **B5N3** with a Mitsubishi Kasei engine and the **B5N2-S** night fighter, armed with oblique-firing 20mm cannon, but neither entered mass production.

Operators

The primary and essentially sole military operator was the Imperial Japanese Navy Air Service, which deployed the type from carriers such as Akagi and Kaga and from land bases throughout the Pacific Ocean and Southeast Asia. Post-war, a small number of captured aircraft were evaluated briefly by the United States Navy and possibly by the forces of the Republic of China Air Force, but none saw operational use.

Specifications (B5N2)

* **Crew:** 3 (pilot, navigator/bombardier, radio operator/gunner) * **Length:** 10.3 m (33 ft 10 in) * **Wingspan:** 15.518 m (50 ft 11 in) * **Powerplant:** 1 × Nakajima Sakae 11 14-cylinder air-cooled radial engine * **Maximum speed:** 378 km/h (235 mph) * **Range:** 1,991 km (1,237 mi) * **Service ceiling:** 8,260 m (27,100 ft) * **Armament:** 1 × rear-facing 7.7 mm Type 92 machine gun * **Bombs:** 1 × 800 kg (1,764 lb) Type 91 torpedo or equivalent bomb load

Surviving aircraft

No complete, original Nakajima B5N airframes are known to exist today. Wreckage believed to be from this aircraft type has been located in various locations, including Lake Lake Kasumigaura in Japan and jungles in the Solomon Islands. The only known full-scale representation is a meticulously crafted, non-flying replica displayed at the Pacific Aviation Museum Pearl Harbor on Ford Island in Hawaii, serving as a historical tribute to its role in the December 1941 attack.

Category:Military aircraft of Japan Category:World War II torpedo bombers