While working with theMitsubishi company, the British aircraft designerHerbert Smith designed the 2MT1 two-seatbiplane torpedo bomber, which flew for the first time in January1923.[1] It went into Japanese Navy service as theType 13-1 carrier-borne attack aircraft orB1M1 and was followed by the2MT2 and2MT3 variants (also designated B1M1). The redesignedType 13-2 was designatedB1M2. The final version, theType 13-3 orB1M3, had the company designation3MT2 and was a three-seater. Total production was 443.[1] The B1M was powered by a 450 hp (340 kW)Napier Lion orHispano-Suiza engine according to version.
The type entered service in 1924 and served into the 1930s, with thirty-two flying from theaircraft carriersKaga andHōshō during theShanghai Incident in 1932.[1] An aircraft fromKaga was lost during an aerial engagement between an American air force adviser and demonstration pilot to the Chinese government, Robert Short, who lost his life and was regarded as a hero defending the Chinese city against Japanese aircraft.[2] Four days later, a 15-aircraft formation composed ofNakajima A1N fighters and B1Ms attackedQiaosi Airbase in Hangzhou, and, in the ensuing dogfight, at least one ChineseJunkers K 47 fighter was shot down.[3]
From 1929, a number of surplus B1Ms were converted for civilian use, being fitted with an enclosed cabin for passengers or cargo.
Prototype of the B1M2 / Navy Type 13-2 Carrier Attack Aircraft, two-seat torpedo bomber powered by 450 hp (340 kW)Mitsubishi Hi V-12 engine (licensed builtHispano-Suiza Lb). One built.
Civil conversion of B1M. Several variations on type. Enclosed cabin for two or three passengers. Powered by original Lion or Hispano-Suiza engines or converted with licensed builtBristol Jupiterradial engine. Also known asType 13th Year Converted Aeroplane.[4]
1 X as second letter is for experimental aircraft or imported technology demonstrators not intended for service,2 Hyphenated trailing letter (-J, -K, -L, -N or -S) denotes design modified for secondary role,3 Possibly incorrect designation, but used in many sources
