Military Wiki
Role Torpedo Bomber
Manufacturer Yokosuka
Introduction 1933
Primary user Imperial Japanese Navy Air Service
Number built 129

The Yokosuka B3Y, or Navy Type 92 Carrier Attack Bomber was a Japanese carrier-based torpedo bomber of the 1930s. It was designed by the Yokosuka Naval Air Technical Arsenal, and while unimpressive during testing, it was ordered into service by the Imperial Japanese Navy and used until replaced by more capable aircraft.

Development and design

In 1932, the Imperial Japanese Navy had a requirement, 7-Shi,[1] for a new torpedo bomber to replace the Mitsubishi B2M. The air arsenal at Yokosuka prepared its own design to meet this requirement, competing against designs by Mitsubishi and Nakajima.

The resulting aircraft was a three-seat single-engine biplane, with a fuselage of steel tube construction and two-bay wooden wings that could fold rearwards for storage aboard aircraft carriers. It was powered by a single Hiro Type 91 W engine rated at 450 kW (600 hp).[2] Testing proved that the aircraft had poor stability and control, and that the engine was unreliable. The competing Mitsubishi and Nakajima aircraft were even less successful however, and after modifications made by Tokuichiro Gomei of Aichi Kokuki, the aircraft was accepted by the Navy in August 1933 as the Type 92 Carrier Attack Bomber, with a short designation of B3Y1, with production by Aichi, Watanabe and the Hiro Naval Arsenal, 129 being produced by the time that production finished in 1936.[2]

Operational history

The B3Y1 continued to be prone to engine problems, which frequently caused the type to be grounded. It served operationally in the early part of the Second Sino-Japanese War,[3][4] gaining a good reputation for accurate level bombing against small targets.[2] The B3Y was gradually phased out of operational service, being replaced by Aichi's D1A dive bomber and Yokosuka's B4Y torpedo bomber.[2]



Specifications (B3Y1)

Data from Japanese Aircraft, 1910–1941[2]

General characteristics

  • Crew: 3
  • Length: 9.50 m (31 ft 2 in)
  • Wingspan: 13.51 m (44 ft 3 34 in)
  • Height: 3.73 m (12 ft 2 34 in)
  • Wing area: 50 m2 (538 ft2)
  • Empty weight: 1,850 kg (4,087 lb)
  • Loaded weight: 3,200 kg (7,045 lb)
  • Powerplant: 1 × Hiro Type 91 12-cylinder W-block inline water-cooled engine, 450 kW (600 hp)


  • Maximum speed: 219 km/h (118 kn, 136 mph)
  • Wing loading: 64.0 kg/m2 (13.1 lb/ft2)
  • Power/mass: 0.14 kW/kg (0.085 hp/lb)
  • Endurance: 4 12 hours


  • 1× fixed, forward-firing 7.7 mm (.303 in) machine gun and 1× flexible, rearward-firing machine gun in observer's cockpit
  • 1× 800 kg (1,764 lb) torpedo or 500 kg (1,102 lb) bombs
  • See also


    • Mikesh, Robert C.; Shorzoe Abe (1990). Japanese Aircraft, 1910–1941. London: Putnam Aeronautical Books. ISBN 0-85177-840-2. 

    External links

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