Mitsubishi Ki-57 / MC-20 / L4M TOPSY
|TRANSPORT||Virtual Aircraft Museum / Japan / Mitsubishi|
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, which was flown in August 1940; it differed from the Ki-21 by having low-set monoplane wings and a new fuselage to seat up to 11 passengers. Following satisfactory testing the type was ordered into production 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. The Ki-57-I was superseded from early 1942 by the improved Ki-57-ll, which introduced more powerful Mitsubishi Ha-T02 engines and a number of refinements. This had the civil and military designations MC-20-II and Army Type 100 Transport Model 2 respectively, production totalling 406. A small number of Ki-57-ls transferred for use by the Japanese navy were rede-signated L4M1, and all of these versions had the Allied codename 'Topsy'.