The Mitsubishi B1M was a Japanese torpedo bomber of the 1920s, also known as the Navy Type 13 Carrier-Borne Attack Aircraft.
It was designed and built by Mitsubishi and used in combat against China.
The aircraft was used by the air services of the Imperial Japanese Navy and Imperial Japanese Army.
While working with the Mitsubishi company, the British aircraft designer Herbert Smith designed the 2MT1 two-seat biplane torpedo bomber which flew for the first time in January 1923.
It went into Japanese Navy service as the Type 13-1 carrier-borne attack aircraft or B1M1 and was followed by the 2MT2 and 2MT3 variants (also designated B1M1).
The redesigned Type 13-2 was designated B1M2.
The final version, the Type 13-3 or B1M3, had the company designation 3MT2 and was a three-seater.
Total production was 443.
The B1M was powered by a 450 hp (340 kW) Napier Lion or Hispano-Suiza engine according to version.
Variants
Navy long formal designations
Navy Type 13-1 Carrier Attack Aircraft
B1M1
Navy Type 13-2 Carrier Attack Aircraft
B1M2
Navy Type 13-3 Carrier Attack Aircraft
B1M3
Navy short designations
B1M1
Initial two seat production version powered by 450 hp (340 kW) Napier Lion engine.
197 built by Mitsubishi.
B1M2
Three-seat production torpedo bomber, based on 2MT5, powered by Mitsubishi Hi V-12 engine.
115 built by Mitsubishi.
B1M3
Improved B1M2 with revised propeller and reduction gear.
128 built by Mitsubishi and Hiro Naval Arsenal.
Company designations
2MT1
Navy Type 13-1 Carrier Attack Aircraft / B1M1
2MT2
Navy Type 13-1 Carrier Attack Aircraft / B1M1
2MT3
Navy Type 13-1 Carrier Attack Aircraft / B1M1
2MT4
Experimental reconnaissance seaplane version.
One built.
2MT5
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
