Polikarpov I-15

Polikarpov I-15
Kogo · GFDL · source
Name	I-15
Type	Fighter aircraft
Manufacturer	Polikarpov
Designer	Nikolai Polikarpov
First flight	October 1933
Introduced	1934
Retired	1950s (Spanish service)
Primary user	Soviet Air Forces
Number built	3,313 (all variants)
Developed from	Polikarpov I-5
Developed into	Polikarpov I-153

Polikarpov I-15. The Polikarpov I-15 was a Soviet biplane fighter aircraft of the 1930s. Nicknamed "Chaika" (Seagull) due to its distinctive gull-wing upper wing, it was renowned for its exceptional maneuverability. It saw extensive combat during the Spanish Civil War, the Second Sino-Japanese War, and the early stages of the Second World War.

Design and development

The I-15 was designed by Nikolai Polikarpov at TsKB as a successor to the Polikarpov I-5. Its most recognizable feature was the gull-wing design, intended to improve pilot visibility. The aircraft was of mixed construction, featuring a fuselage with a steel tube framework and fabric covering, while the wings were wooden. Power was provided by a single Shvetsov M-25 radial engine, a license-built version of the American Wright R-1820 Cyclone. Flight testing, conducted by pilot V.P. Chkalov, demonstrated outstanding aerobatic capabilities and a tight turning radius, making it highly effective in dogfighting. The design bureau faced significant pressure from Joseph Stalin and the People's Commissariat of the Aviation Industry to produce a capable fighter rapidly amidst the Great Purge.

Operational history

The I-15 first saw major combat in the Spanish Civil War, where it was supplied to the Spanish Republic as part of Soviet aid. Republican pilots and international volunteers of the International Brigades, such as those in the Abraham Lincoln Brigade, flew it with great success against the Nationalist Heinkel He 51 and Fiat CR.32 biplanes. It also fought in the Second Sino-Japanese War with the Republic of China Air Force, engaging Imperial Japanese Army Air Service aircraft like the Nakajima Ki-27. By the time of the Battle of Khalkhin Gol against Japan and the Winter War against Finland, it was becoming obsolete. During the German invasion of the Soviet Union in 1941, I-15s were largely relegated to ground attack duties, suffering heavy losses against the Luftwaffe's modern Messerschmitt Bf 109 fighters. Some served as Ushakov night bombers until 1943.

Variants

The primary initial model was the I-15, powered by the M-25 engine. The I-15bis (or I-152) was a major revision that replaced the gull wing with a straight upper wing and featured a more powerful Shvetsov M-25V engine. The I-15ter (designated Polikarpov I-153 upon service entry) reintroduced the gull wing and a retractable landing gear, becoming the definitive development. Several one-off prototypes were built, including the I-15UD with a Klimov M-100 engine and the I-15GK with a pressurized cabin for high-altitude research. A two-seat trainer version was designated DI-15.

Operators

The primary operator was the Soviet Air Forces (VVS). Significant numbers were exported to the Spanish Republic during its civil war. The Republic of China received I-15s, which were flown by both Chinese pilots and Soviet volunteers from the Soviet Volunteer Group. After the Spanish Civil War, captured aircraft were used by the Spanish Air Force of Francisco Franco's regime. The Mongolian People's Army also operated the type. Following the Winter War, Finland captured several I-15bis aircraft and used them for training. Post-war, some were transferred to satellite states, though they were largely phased out by the late 1940s.

Specifications (I-15bis)

* Crew: One * Length: 6.27 m (20 ft 7 in) * Wingspan: 10.2 m (33 ft 6 in) * Height: 2.19 m (7 ft 2 in) * Wing area: 22.5 m² (242 ft²) * Empty weight: 1,310 kg (2,888 lb) * Gross weight: 1,730 kg (3,814 lb) * Powerplant: 1 × Shvetsov M-25V 9-cylinder air-cooled radial piston engine, 560 kW (750 hp) * Maximum speed: 370 km/h (230 mph, 200 kn) at 3,500 m (11,483 ft) * Range: 770 km (480 mi, 420 nmi) * Service ceiling: 9,800 m (32,200 ft) * Armament: 4 × 7.62 mm PV-1 machine guns or 2 × UB machine guns; up to 150 kg (330 lb) of bombs or RS-82 air-to-ground rockets

Category:Biplane aircraft Category:Soviet fighter aircraft 1930–1939 Category:Polikarpov aircraft