Developed from mid 1938 by Dmitrii L Tomashevich (one of Polikarpov's deputies), the I-180 was originally conceived with an all-metal structure. Limited all-metal construction experience, however, led the Polikarpov OKB to adopt an essentially similar structure to that of the earlier I-16, with a wooden monocoque fuselage and a fabric-skinned metal wing. The first prototype, the I-180.1, was powered by a 1,100hp Tumansky M-88 14-cylinder two-row radial, intended armament being four 7.62mm guns. This aircraft was lost as a result of engine failure during its first flight on 15 December 1938. The second prototype, the I-180.2, differed primarily in having a 1,000hp Tumansky M-87A (later M-87B) 14-cylinder two-row radial and lengthened wing outer panels. These increased wing span from 9.00m to 10.05m and area from 14.68sq.m to 16.11sq.m. First flown on 19 April 1939, the I-180.2 was lost on its 53rd flight. A third prototype, the I-180.3 flown on 10 February 1940, featured a redesigned and more advanced wing structure, a 1,100hp M-88R engine, a cockpit canopy and an armament of two 12.7mm and two 7.62mm guns concentrated in the fuselage. Flown with both wheel and ski undercarriages, the I-180.3 was lost in an accident during State Acceptance Trials.
In the meantime, a pre-series of 10 aircraft based on the I-180.2 had been under construction as the I-180S (Seriyny or Series), the first three of these having been completed in December 1939. The I-180S was powered by the M-88R and carried an armament of two 12.7mm and two 7.62mm fuselage-mounted guns, and, like the I-180.3, featured an enclosed cockpit. The I-180S was cleared for service trials, but the results of these were academic as this fighter had been overtaken by the more advanced I-185. As a part of the I-185 development programme, one pre-series I-180S fighter had the dated triangulated pattern mainwheel legs replaced with legs of cantilever type, this aircraft being referred to as the I-180Sh, the suffix indicating Shassi (chassis). In the event, it was not completed and flown, the entire I-180 programme having meanwhile been abandoned.
Max take-off weight: 2456 kg / 5415 lb
Empty weight: 2046 kg / 4511 lb
Wingspan: 10.09 m / 33 ft 1 in
Length: 6.88 m / 23 ft 7 in
Wing area: 16.11 sq.m / 173.41 sq ft
Max. speed: 585 km/h / 364 mph