The Polikarpov I-5 was a single-seat biplane which became the primary Soviet fighter between its introduction in 1931 through 1936, after which it became the standard advanced trainer.

Following Operation Barbarossa, which destroyed much of the Soviet Air Forces (VVS), surviving I-5s were equipped with four machine guns and bomb racks and pressed into service as light ground-attack aircraft and night bombers in 1941.

The 1928 Five-Year Plan ordered the Tupolev design bureau to develop a mixed-construction (metal and wood/fabric) biplane fighter powered by a Bristol Jupiter VII engine with the first prototype completed by 1 September 1929.

[1] Nikolai Polikarpov was arrested by the OGPU in September 1929 for the crime of industrial sabotage for these failures and sentenced to death, although this was commuted to ten years imprisonment in a labor camp.

The full-scale mock-up was approved on 28 March 1930 and the first prototype, designated VT-11 (Vnutrenniya Tyurma—Internal Prison), was completed a month later.

The third prototype, designated as the VT-13 and inscribed with "A Gift for the XVIth Congress of the Party", was powered by a 600-horsepower (450 kW) Soviet-built M-15 engine with a NACA cowling, but this proved to be unreliable and was not put into production.

One problem noted during the trials was a tendency to make an uncontrolled 180° turn (ground looping) when landing in light winds.

They all had imported engines fitted, but trialled various small improvements for the production aircraft that included cooling vents for the crankcase, introduction of a pitot tube and static vent in the starboard upper wing, a faired headrest for the pilot, and a metal propeller whose pitch could be adjusted on the ground.

[4] The I-5 was a single-seat biplane with the upper wing slightly larger than the lower, and a fixed landing gear with a tailskid.

The conventional landing gear was connected by a one-piece axle and some aircraft were fitted with teardrop-shaped spats covering the wheels.

[7] I-5s called up during the emergency in 1941 were converted for use as fighter-bombers by adding two more machine guns, and some aircraft were fitted with the heavy bombs that had been rejected earlier.

The I-5 was first delivered to units in the Leningrad, Ukraine and Transbaikal Military Districts and comprised 20% of the VVS's fighter force by the end of 1932.

During 1933 deliveries began to units in the Far Eastern, Belorussian and Moscow Military Districts and they comprised 40% of the fighter strength by the end of the year.

The I-5 began to be replaced by the Polikarpov I-15 in 1936, and was completely phased out from front-line use by the end of 1937, but continued to be employed as an advanced trainer.

Some I-5s were used by the 605th and 606th Fighter Regiments (Istrebitel'nyye Aviatsionnyye Polki (IAP)) during the defence of Moscow as night bombers until re-equipping in February 1942.

[10] The 2nd Ground Attack Regiment (Shturmovoy Aviatsionnyi Polk (ShAP)) was raised in September 1941 in the Crimea from reservists and the Kachin Flying School.

[12] 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.