Yokosuka B4Y

The Yokosuka B4Y was a carrier-based torpedo bomber used by the Imperial Japanese Navy between 1936 and 1943. It first saw combat action in 1937, during the Sino-Japanese War, carrying out bombing missions against Chinese Navy ships and coastal bases and cities.  Two B4Ys sank the USS Panay(PR-5) gunboat, which patrolled the Chinese Yangtze River on December 12, 1937. It also took part in the first two years of World War II. Taking off from Hosho aircraft carrier, eight Yokosuka B4Y dive bombers participated in the Battle of Midway. By 1943, it had become outdated and was phased out, being replaced by the Nakajima B5N.

The Yokosuka B4Y was a three-seat biplane capable of carrying a bombload of 800 kg. It was powered by one Nakajima Hikari-2, 9-cylinder engine, that delivered 840 horsepower during take-off. It had an all-metal structure and its two wings were secured with “N” trusses. Like all biplanes, it was fitted with fixed landing gear. It was armed with one backward-firing, 7.7mm machine gun, which was mounted in rear cockpit.


Type: naval torpedo-bomber

Wingspan: 49′ 3″ (15 m)

Length: 33′ 3″ (10.15 m)

Height: 14′ 3″ (4.36 m)

Maximum speed: 171 mph (278 km/h)

Range: 980 miles (1,585 km)


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Thor is Carlos Benito Camacho, the manager and writer of this blog.