The VI-100 was an all-metal low-wing cantilever monoplane powered by two Klimov M-105R engines, licence-built Hispano-Suiza 12Y engines that were the most advanced then available in the Soviet Union, driving VISh-42 three-blade variable-pitch propellers, enhanced by two TK-3 turbo-superchargers fitted in the engine nacelles. Its primary armament were two 20 mm ShVAK cannon and two 7.62 mm ShKAS machine guns, with another ShKAS machine gun in a fixed mounting in the tailcone for self-defence. The first prototype VI-100 was also designed to carry KS-76 (48 modified 76 mm artillery shells with timed fuses) or KS-100 (96 AO-25 bomblets) cassettes in the fuselage for dropping on enemy bomber formations. The second prototype was instead fitted with external bomb racks for 1,000 kg of bombs and internal bomb bays for 600 kg of bombs instead of the cassettes of the first prototype.