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, 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
A Mitsubishi Ki-57-II "Topsy" of the Imperial Japanese Army during 1943
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
covered by the Allied codename 'Topsy'.
Ki-57-I Army Type 100
Transport Model 1 - Powered by two 950 hp (708 kW) Nakajima Ha-5 KAI
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 Japan Air Lines (Dai Nippon Koku KK).
Ki-57-II Army Type 100
Transport Model 2 - Powered by two 1,080 hp (805 kW) Mitsubishi Ha-l02
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
MC-20-II - Same as
above but built for civil use with Japan Air Lines (Dai Nippon Koku KK).
L4M1 - A small number
of Ki-57-IIs were transferred for use by the Japanese navy as
transports and were redesignated L4M1.
(Army Type 100
Transport Model 2 - Mitsubishi Ki-57-II)
Passenger Personnel Transport
Pilot, Co-Pilot, Navigator and Radio Operator.
Mitsubishi Jukogyo KK Design Team to create a civil version of the
Ki-21 bomber initially for Japan Air Lines (Dai Nippon Koku KK)
Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries
(Ki-57-I) Two 950 hp (708 kW) Nakajima Ha-5 KAI radial engines.
(Ki-57-II) Two 1,080 hp (805 kW) Mitsubishi Ha-102 14-cylinder
air-cooled radial engines.
Maximum speed 292 mph (470 km/h) at 19,030 ft (5800 m); service ceiling
26,245 ft (8000 m).
Range: 1,864 miles (3000 km) on internal fuel.
12,313 lbs (5585 kg) with a maximum take-off weight of 20,106 lbs (9120
74 ft 1 3/4 in (22.60 m); length 52 ft 9 3/4 in (16.10 m); height 15 ft
11 in (4.85 m); wing area 754.36 sq ft
(70.08 sq m).
Mitsubishi Ki-57 (prototype), MC-20-1 (civil production), Ki-57-I Army
Type 100 Transport Model 1 (military production), MC-20-II (civil
production), Ki-57-II Army Type 100 Transport Model 2 (military
production), L4M1 (naval).
Standard communications and navigation equipment.
flight (prototype) August 1940; service introduction (Ki-57-II) early
(Imperial Japanese Army & Navy), China (Nationalist Chinese Air Force -
a few captured aircraft only)