Mitsubishi MC-20 / Ki-57 / L4M1
With interest shown by Japan Air Lines for a civil version of the Mitsubishi Ki-21 bomber, the company built a Mitsubishi Ki-57 prototype with the civil designation MC-20, which was flown in August 1940.
Essentially, the Ki-57 (Topsy to the Allies) was a low wing version of the Ki-21-I bomber, except for a redesigned fuselage which accommodated a crew of two and up to 11 passengers. The powerplant consisted of two 950-hp Nakajima Ha-5 Kai 14-cylinder radials. The main wheels retracted into the engines nacelles.
Following satisfactory testing the type was ordered into production in 1940 for civil and military use under the designations MC-20-1 and Army Type 100 Transport Model 1 respectively (Mitsubishi Ki-57-I), 100 series aircraft being built.
After 101 of these had been built, Mitsubishi in 1942 replaced this version on the production line with the Ki-57-II Army Type 100 Transport Model 2 /MC-20-II, generally similar but with 1080-hp Mitsubishi Ha-102 radials. They continued in production until January 1945, by which time 406 of this improved model had been completed.
A small number of Ki-57-IIs transferred for use by the Japanese navy were redesignated L4M1 or Navy Type 0 Transport Model 11, and all of these versions had the Allied codename 'Topsy'.
The Ki-57 featured most notably in the paratroop attack on the airfield at Palembang and neighbouring oil refineries in February 1942.
Engine: 2 x 1080-hp Mitsubishi Ha-102, 810kW
Wingspan: 22.6 m / 74 ft 2 in
Length: 16.1 m / 52 ft 10 in
Height: 4.77 m / 15 ft 8 in
Wing area: 70.08 sq.m / 754.33 sq ft
Max take-off weight: 8173-9120 kg / 18018 - 20106 lb
Empty weight: 5585 kg / 12313 lb
Max. speed: 470 km/h / 292 mph
Ceiling: 8000 m / 26250 ft
Range w/max.fuel: 3000 km / 1864 miles
Range w/max.payload: 1500 km / 932 miles
Mitsubishi Ki-57 / MC-20 / L4M TOPSY