Tupolev TB-1
…I-4 fighters over the aircraft's wings as parasite aircraft. The TB-1 was replaced as a heavy bomber by the similar, but much larger, four-engined Tupolev TB-3, with many aircraft being converted to civil freighters (designated G-1) for use by Aeroflot and Aviaarktika, Aeroflot's polar division. One Avia Arktika…