Junkers JU-52Junkers JU 52 model airplane. The Ju 52 trimotor, like the USAF C 47, was first built in the 1930s yet remained in service for more than a quarter century. This transport made its maiden flight in April 1931 and three years later a heavy bomber version appeared. The latter aircraft formed the nucleus of the Luftwaffe's infant bomber force in the mid 1930s, and it was used during the Spanish Civil War. The Ju 52 was obsolete as a bomber by 1939, but