The I-5 was involved in tests of the Zveno project where a Tupolev TB-3 heavy bomber carried three I-5s as parasite fighters. One I-5 was carried was on each wing and a third over the fuselage. Ramps were used to get the wing-mounted aircraft to their places, but the fuselage-mounted aircraft had to be lifted by hand. This was so cumbersome that they were generally used solely as an extra powerplant for the TB-3 later in the program. The aircraft used in these trials used the longer landing gear with smaller tires originally used in the prototypes. August 1934.