The Polikarpov I-16 (Russian: Поликарпов И-16) is a Soviet single-engine single-seat fighter aircraft of revolutionary design; it was the world's first low-wing cantilever monoplane fighter with retractable landing gear to attain operational status and as such "introduced a new vogue in fighter design". The I-16 was introduced in the mid-1930s and formed the backbone of the Soviet Air Force at the beginning of World War II. The diminutive fighter, nicknamed "Ishak" or "Ishachok" ("donkey" or "burro") by Soviet pilots, figured prominently in the Second Sino-Japanese War, the Battle of Khalkhin Gol, Winter War and the Spanish Civil War – where it was called the Rata ("rat") by the Nationalists or Mosca ("fly") by the Republicans. While working on the Polikarpov I-15 biplane, Nikolai Nikolaevich Polikarpov began designing an advanced monoplane fighter. It featured cutting-edge innovations such as retractable landing gear and a fully enclosed cockpit, and was optimized for speed with a short stubby fuselage, and a Wright R-1820 radial engine in a NACA cowling. The aircraft is small, light and simple to build. Full-scale work on the TsKB-12 prototype began in June 1933, and the aircraft was accepted into production on 22 November 1933, a month before it took to the air. The TsKB-12 was of mixed construction, using a wooden monocoque fuselage and wings employing a KhMA chrome-molybdenum steel alloy wing spar, dural ribs and D1 aluminum alloy skinning on the center and leading edges, with the remaining portions of the wings fabric covered. Another modern feature were the ailerons which ran along almost the entire trailing edge of the wing and also operated as flaps (in the manner of more modern flaperons) by drooping 15°. The cockpit was covered by a 40-centimetre-wide (16 in) canopy which featured an Aldis-type tubular gun sight which could slide back and forth on runners fitted with rubber bungee cords. A 225 l (59.4 US gal) fuel tank was fitted directly in front of the cockpit. The main landing gear is fully retractable by a hand crank. The armament consisted of a pair of 7.62×54mmR (0.30 in) ShKAS machine guns in the wings, mounted on the outboard side of the main gear and 900 rounds of ammunition. A total of 10,292 (6,848 fighters and 3,444 trainers) werre built. For more details of design and deevelopment, operational history and an extensive list of variants, click here.
