Mitsubishi Ki-57 (Topsy)
MC-20-I / Type 100 Transport Model 1
Technical Information

Background
When in 1938 the Mitsubishi Ki-21 heavy bomber began to enter service with the Imperial Japanese Army, its capability attracted the attention of Japan Air Lines. In consequence a civil version was developed and this, generally similar to the Ki-21-I and retaining its powerplant of two 950 hp (708 kW) Nakajima Ha-5 KAI radial engines.

The civil and military version, known as the MC-20-I differed primarily by having the same wings transferred from a mid to low-wing configuration and the incorporation of a new fuselage to provide accommodation for up to 11 passengers. This transport version appealed also the the Navy, and following the flight of a prototype in August 1940 and subsequent testing, the type was ordered into production for both civil and military use. The military version was designated the Type 100 Transport Model 1.

This initial production Mitsubishi 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 L4Ml. After the last of the Ki-51s had been delivered production was switched to an improved Ki-57-II, which introduced more powerful 1,080 hp (805 kW) 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, and 406 were built before production ended in January 1945. Both versions were assigned the Allied codename "Topsy".

Technical Details
Crew  Four (pilot, co-pilot, navigator and radio operator)
Engine  2 x 950 hp (708 kW) Nakajima Ha-5 KAI radial engines
Span  74 ft 1 3/4 in
Length  52 ft 9 3/4 in
Height  15 ft 11 in
Maximum Speed  292 mph
Range  1,864 miles
Cargo  11 Passengers or cargo