The Mitsubishi B1M was a Japanese

torpedo bomber A torpedo bomber is a military aircraft designed primarily to attack ships with aerial torpedoes. Torpedo bombers came into existence just before the First World War almost as soon as aircraft were built that were capable of carrying the weight ...

of the 1920s, also known as the Navy Type 13 Carrier-Borne Attack Aircraft. It was designed and built by

Mitsubishi The is a group of autonomous Japanese multinational companies in a variety of industries. Founded by Yatarō Iwasaki in 1870, the Mitsubishi Group historically descended from the Mitsubishi zaibatsu, a unified company which existed from 1870 ...

and used in combat against

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. The aircraft was used by the air services of the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

and

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emper ...

Development

While working with the

company, the British aircraft designer

Herbert Smith Herbert Smith LLP was a multinational law firm headquartered in London, United Kingdom. The firm was founded in the City of London in 1882 by Norman Herbert Smith and merged with the Australian law firm Freehills on 1 October 2012, forming Herb ...

designed the 2MT1 two-seat

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...

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

Napier Lion The Napier Lion is a 12-cylinder, petrol-fueled 'broad arrow' W12 configuration aircraft engine built by D. Napier & Son from 1917 until the 1930s. A number of advanced features made it the most powerful engine of its day and kept it in produ ...

Hispano-Suiza Hispano-Suiza () is a Spanish automotive–engineering company. It was founded in 1904 by Marc Birkigt and Damian Mateu as an automobile manufacturer and eventually had several factories in Spain and France that produced luxury cars, aircraft en ...

engine according to version.

Operational history

The type entered service in 1924 and served into the 1930s, 32 flying from the

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

s and during the Shanghai Incident in 1932. An aircraft from ''Kaga'' was lost during an aerial engagement between an American air force adviser and demonstration pilot to the Chinese government, Robert Short, who also lost his life, and regarded as a hero defending the Chinese city against the Japanese aircraft. Four days later, a 15-aircraft formation composed of

Nakajima A1N The Nakajima A1N, or Navy Type 3 Carrier Fighter, was a Japanese carrier-based fighter of the late-1920s and early-1930s. It was a licensed copy of the British Gloster Gambet fighter, built by the Nakajima Aircraft Company for the Imperial Ja ...

fighters and B1Ms attacked Qiaosi Airbase in Hangzhou, and in the ensuing dogfight, at least one Chinese

Junkers K 47 The Junkers K 47 was a two-seater fighter aircraft developed in Sweden by the Swedish subsidiary of the German firm Junkers during the late 1920s, a civil development of which was designated the A 48. Design and development Designed to meet a r ...

fighter was shot down. From 1929, a number of surplus B1Ms were converted for civilian use, being fitted with an enclosed cabin for passengers or cargo.

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

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 ''Ohtori'' :Experimental

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops ( skirmishe ...

seaplane A seaplane is a powered fixed-wing aircraft capable of taking off and landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their technological characteri ...

version. One built. ;2MT5 ''Tora'' :Prototype of the B1M2 / Navy Type 13-2 Carrier Attack Aircraft, two-seat torpedo bomber powered by Mitsubishi Hi V-12 engine (licensed built Hispano-Suiza Lb). One built. ;3MT1 :Navy Type 13-2 Carrier Attack Aircraft / B1M2 ;3MT2 :Navy Type 13-3 Carrier Attack Aircraft / B1M3

Army designations

;Mitsubishi Army Type 87 Light Bomber :Mitsubishi B1Ms used by the IJAAS .

Civilian designations

;T-1.2 Converted Aeroplane :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 built

Bristol Jupiter The Bristol Jupiter was a British nine-cylinder single-row piston radial engine built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turn ...

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

. Also known as Type 13th Year Converted Aeroplane.

Operators

; *

Specifications (2MT2)

References

External links

*http://www.csd.uwo.ca/~pettypi/elevon/gustin_military/db/index.html {{Japanese Navy short aircraft designations B1M, Mitsubishi B1M Carrier-based aircraft Biplanes Single-engined tractor aircraft Aircraft first flown in 1923