The Mitsubishi Ki-57 was a Japanese passenger transport aircraft, developed from the Ki-21 bomber, during the early 1940s.

Development

In 1938, when the Ki-21

heavy bomber Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range ( takeoff to landing) of their era. Archetypal heavy bombers have therefore usually been among the larg ...

began to enter service with the

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 ...

, its capability attracted the attention of the

Imperial Japanese Airways was the national airline of the Empire of Japan during World War II. History With the start of the Second Sino-Japanese War, there was a tremendous need for air transport capability by the Japanese military, which had traditionally drawn on th ...

. In consequence a civil version was developed and this, generally similar to the Ki-21-I and retaining its powerplant of two 708 kW (950 hp) Nakajima Ha-5 KAI

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 ...

s, differed primarily by having the same wings transferred from a mid to low-wing configuration and the incorporation of a new

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

to provide accommodation for up to 11 passengers. This transport version appealed also the navy, and following the flight of a

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and software programming. A prototype is generally used to ...

in August 1940 and subsequent testing, the type was ordered into production for both civil and military use. This initial production ''Ki-57-I'' had the civil and military designations of ''MC-20-I'' and ''Army Type 100 Transport Model 1'', respectively. A total of 100 production Ki-57-Is had been built by early 1942, and small numbers of them were transferred for use by the Japanese navy in a transport role, then becoming redesignated ''L4M1''. After the last of the Ki-57s had been delivered production was switched to an improved ''Ki-57-II'', which introduced more powerful 805 kW (1,080 hp) Mitsubishi Ha-l02 14-cylinder radial engines installed in redesigned nacelles and, at the same time, incorporated a number of detail refinements and minor equipment changes. Civil and military designations of this version were the ''MC-20-II'' and ''Army Type 100 Transport Model 2'', respectively. Only 406 were built before production ended in January 1945. Both versions were covered by the Allied reporting name "Topsy".

Variants

*''Ki-57-I Army Type 100 Transport Model 1'': Powered by two

Nakajima Ha5 KAI The Nakajima Ha5 is a twin row, 14 cylinder air-cooled radial aircraft engine built by the Japanese Nakajima Aircraft Company. The engine was a development of earlier single-row Japanese engines, the Kotobuki and Hikari, which had combined ...

radial engines and a redesigned fuselage to accommodate 11 passengers. About 100 aircraft of this type were built including the civil version. *''MC-20-I'': Same as above but built for civil use with

(Dai Nippon Koku KK). *''Ki-57-II Army Type 100 Transport Model 2'':Powered by two Mitsubishi Ha-102 Zuisei 14-cylinder radial engines installed in redesigned nacelles. Minor equipment and detail refinements were also incorporated. 306 aircraft of this type were produced before the end of production in January 1945. *''MC-20-II'': Same as above but built for civil use with Imperial Japanese Airways (Dai Nippon Koku KK). *''L4M1'': A small number of Ki-57-Is were transferred for test by the Japanese navy as transports and were redesignated L4M1.

Operators

Wartime

Military operators ; *

Imperial Japanese Army Air Force The Imperial Japanese Army Air Service (IJAAS) or Imperial Japanese Army Air Force (IJAAF; ja, 大日本帝國陸軍航空部隊, Dainippon Teikoku Rikugun Kōkūbutai, lit=Greater Japan Empire Army Air Corps) was the aviation force of the Im ...

Imperial Japanese Navy Air Service The was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired their first aircraft in 1910 ...

; *

Manchukuo Imperial Air Force The Manchukuo Imperial Air Force (') ( was the air force of the Empire of Manchuria, a puppet state of Imperial Japan. The air force's predecessor was the Manchukuo Air Transport Company (later renamed the Manchukuo National Airways), a paramilit ...

Civil operators ; *

(''Dai Nippon Koku KK'') *

Asahi Shimbun is one of the four largest newspapers in Japan. Founded in 1879, it is also one of the oldest newspapers in Japan and Asia, and is considered a newspaper of record for Japan. Its circulation, which was 4.57 million for its morning edition a ...

* Osaka Mainichi Shimbun * Tyuka Koku Kaisya (in China) ; *

Manchukuo National Airways Manchuria Aviation Company(traditional Chinese/Kyūjitai: 滿洲航空株式會社; simplified Chinese: 满州航空株式会社; Shinjitai: 満州航空株式会社; Japanese Hepburn: ''Manshū Kōkū Kabushiki-gaisha, "MKKK"'') was the nation ...

(in Manchuria) ;

Reorganized National Government of China The Wang Jingwei regime or the Wang Ching-wei regime is the common name of the Reorganized National Government of the Republic of China ( zh , t = 中華民國國民政府 , p = Zhōnghuá Mínguó Guómín Zhèngfǔ ), the government of the pup ...

* One MC-20 used as presidential transport ; * One MC-20 used as presidential transport

Post-war

; * The last Ki-57 was used as a trainer and retired in 1952. ; *

(till October 1945) ; * Captured aircraft, used by the KNIL.

Accidents and incidents

* On December 20, 1940, an Imperial Japanese Airways MC-20-I (J-BGON, ''Myuko'') crashed into Tokyo Bay off Chiba during CAB's test flight, killing all 13 on board including 8 CAB inspectors. * On June 21, 1941, a Manchurian Air Transport MC-20 (M-604) crashed into the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, i ...

, killing all 18 on board.

Specifications (Ki-57-II)

References

;Bibliography * Francillon, Ph.D., René J. ''The Mitsubishi Ki-21 (Aircraft in Profile number 172)''. Leatherhead, Surrey, UK: Profile Publications Ltd., 1967. * (new edition 1987 by Putnam Aeronautical Books, ); 3rd edition 1987 by Putnam Aeronautical Books, 1987. ).

External links

Classic Airplane Museum MC-20
Japanese

Japanese {{Allied reporting names Ki-057 1940s Japanese military transport aircraft Low-wing aircraft Ki-57, Mitsubishi Aircraft first flown in 1940 Twin piston-engined tractor aircraft