Grigorovich I-Z
The Grigorovich I-Z was a fighter aircraft developed in the Soviet Union during the 1930s. Advances in aircraft survivability thanks to all-metal construction and self-sealing and inert gas-filled fuel tanks led to experimentation with large-caliber weapons to shoot them down. In Soviet Union, Leonid Kurchevsky developed a series of recoilless rifles in various calibers and in 1930 was decided to adapt the 76.2 mm weapons for aircraft use.
Design and development
The Grigorovich I-Z was a conventional strut-braced monoplane with fixed landing gear. A pair of Kurchevsky APK rifles were mounted under the wings outside the propeller arc and the rear fuselage and tail assembly were of reinforced metal construction to withstand the blast. A single small-caliber synchronized machine gun in the left fuselage was added to aid the pilot in aiming.The project began in 1930. Two prototypes were built, the first flying in mid-1931. The second strengthened I-Zbis flew at the beginning of the following year. These were followed by 21 examples fitted with the Shvetsov M-22 ordered as evaluation aircraft and 50 production machines. By the time this last batch was being delivered, however, it was already apparent that the concept of a "single-shot" fighter was flawed and the I-Zs that had been built were relegated to various testing roles. One such role was as a parasite fighter in the Zveno project.