The Polikarpov I-180 was designed in an attempt to improve on the I-16, but all three prototypes were lost in crashes, and the type was abandoned after ten pre-production aircraft had been built.
The I-180 is variously described as a expanded 'super I-16' or a lightened version of the Polikarpov Ivanov reconnaissance aircraft of 1936-38. Although the Ivanov was a similar looking aircraft to the I-180 (a low wing monoplane with a basically circular fuselage) it was an all-metal aircraft, while the I-180 retained the largely wooden structure of the I-16.
The first design for the I-180 used the M-87A air-cooled radial engine, but this wasn't powerful enough to provide the expected increase in performance. Unfortunately the only real alternative, the M-88, was still at an early stage in its development, and the early prototypes barely offered any increase in power. Later versions of the engine were more powerful, but by then the I-180 project was effectively over. The first prototype I-180, the I-180-1, was powered by a prototype M-88 engine constructed using parts from the M-87A engine. The new larger engine forced a major redesign of the aircraft, which needed a longer stronger fuselage and a modified wing, with a straight leading edge and swept-forward trailing edge.
The I-180-1 made its maiden flight on 15 December 1938 with the famous test pilot Valery Chkalov at the controls. He made several circuits of the test airfield, but as he was preparing to land the engine seized and the aircraft crashed into some storage facilities. Chkalov suffered fatal injuries in the crash.
Almost inevitable in the paranoid atmosphere of the time the crash was blamed on sabotage. A number of people involved in the project were arrested, amongst them Polikarpov's deputy. Polikarpov probably only escaped arrest himself because he hadn’t approved the test flight.
The second prototype used a standard M-87A engine. Its maiden flight was more successful, although the lower power meant that its performance wasn't as good as hoped, and it had a top speed of 335mph. This aircraft made more than 50 test flights before it two was destroyed in an accident. This time the cause was more obvious - the oil cooler was destroyed during a high altitude test and the aircraft dived into the ground from 10,000ft. Once again the test pilot was killed.
The third prototype was powered by a 1,000hp M-88R engine (M-88P in some sources). This prototype was armed with two ShKAS and two 12.7mm UBS machine guns, had a modified undercarriage and a new oil cooler. Flight tests ran from February to May 1940. Top speed rose to 357mph at 22,600ft and the service ceiling and rate of climb also improved. The third prototype survived its factory trials and was sent for its State Acceptance Tests, but on 5 July the aircraft's control froze while it was upside down. The test pilot was able to escape safely but the aircraft was lost.
Despite these three failures the I-180 was ordered into production at zavod 21 in Gor'kiy. Three of these aircraft took part in the Red Square May Day parade on 1 May 1940, but later in the same month the second production aircraft was written off after a minor crash. In July Polikarpov was present at a meeting in which alterations to the production aircraft were planned, but in October 1940 zavod 21 was ordered to concentrate on the I-16 and the new LaGG-3, and work on the I-180 was abandoned. Polikarpov, now in total command of a smaller design team, moved on to work on the I-185.
Wing span: 33.1ft
Empty Weight: 4,453lb
Take-off Weight: 5,343lb
Max Speed: 357 mph at altitude
Service Ceiling: 36,250ft
Range: 560 miles
Armament: two ShKAS and two 12.7mm UBS machine guns