The Polikarpov SVB-1 was a dive bomber that was one of three different prototypes based on the same TsKB-44 design.
The TsKB-44 design was developed as a multi-purpose ground attack aircraft. The Red Air Force wanted aircraft capable of attacking small but high value battlefield targets, such as tanks or fortifications. Two types of aircraft were requested - one armed with heavy calibre cannon and the other with standard bombs. Polikarpov responded by producing the VIT-1 cannon armed aircraft, the SVB-1 dive bomber and the MPI-1 heavy fighter, all based on the same airframe, designed as the TsKB-44.
SVB stood for 'samolet vozdushnogo boya' or 'aircraft for aerial combat', a somewhat misleading designation for a dive bomber. Like the VIT-1 the SVB-1 was a version of the TsKB-44 three-seat all-metal low wing monoplane, with a retractable undercarriage and two Klimov M-103 engines, each providing 950hp.
The SVB-1 was armed with one flexibly mounted 20mm cannon in the nose and a rear-firing flexibly mounted machine gun. Like the VIT-1 it could carry 1,322lb/ 600kg of bombs in the internal bomb bay, but could also carry extra bombs under the wings (probably 1,102lb/ 500kg under each wing). It was also given disc-like dive brakes on either side of the fuselage. Like all three of the prototypes based on the TsKB-44 design, the SVB-1 was built and made its maiden flight in 1937. All three had good performance and handling, but their take-off and landing runs were too long for the available bases. Further development work was carried out to produce the VIT-2, which was then used to provide the basic outline of a second dive-bomber, the Polikarpov SPB(D).