The Polikarpov I-153 Chaika (Russian: Seagull) was a biplane fighter aircraft that was used by the Soviet Union during World War II.
The I-153 had a Shvetsov M-25 engine that was capable of propelling it at speeds of up to 450 kilometers per hour at 4,600 meters. However, the Shvetsov was quickly replaced by the Shvetsov M-62R engine for improved performance. The armament of the Chaika consisted of four extremely fast firing ShKAS Machine Guns with 2,600 rounds of ammunition between them. The ordnance that could be carried on the Chaika varied between either 200 kilograms worth of bombs or six RS-86 Rockets.
The total weight of the I-153 was around 1,450 kilograms unloaded while total length was 6.1 meters. Wingspan meanwhile was around 10 meters. Being a biplane, the Chaika's operational range was limited to 470 kilometers but the service ceiling of the aircraft was very good at 10,700 meters. Most notable of the design of the Chaika was its inverted gull wings maintained from the earlier Polikarpov I-15. However, to reduce drag, the I-153 had a retractable undercarriage unlike its predecessor.
The main downside of the I-153's inherent upgrades over the earlier I-15s was that with a new engine and new metal frame to support the modified equipment, the weight became substantially heavier, which meant that the Chaika would have less maneuverability. Nonetheless, the I-153 was still used in fundamentally the same role.
The I-153 did not have many variants created during its service life besides the engine upgrade to the M-62, but they were there. The first of these was the I-153P, an upgrade added after combat with the Japanese over Khalkin Gol in which two 20mm ShVAK Autocannons were added as an armament instead of the traditional 7.62mm machine guns. Next were the I-153V and TGK which were given pressured cockpits. The I-153Sh was a ground attack version with further weapons such as more machine guns and bombs added.
The I-153 was developed after the Spanish Civil War in 1938 after experience gained from the conflict showed the existing Soviet fighters being outclassed by more maneuverable Italian biplanes. However, instead of progressing the development of a successor to the I-16, it was decided to create a new and far more advanced biplane that would be superior in every respect to the I-15. Therefore, development began immediately with the first flight taking place in 1938. Following promising results, the aircraft was put into production. However, even by this time, the I-153 was generally quite outdated compared to Germany's Bf 109.
The first combat operation undertaken by an I-153 in Khalkin Gol against Japanese troops. Problems quickly arose with engine maintenance, fires, etc. However, the I-153 was still kept in service with Soviet airmen. By the time of the 1941 invasion, the more advanced Yak-1 and LaGG-3 aircraft had been built only in small numbers, leaving the stores of I-153s to try to engage to Bf 109F-4 fighter aircraft. Results were terrible, with many being shot down trying to take off. In total, around 3,400 examples had been made before and during the war.