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Welcome to the suggestion post for the Nikitin-Shevchenko IS-2! This is a very unique Soviet fighter from the early 1940s. While at a glance it may look like a biplane, the IS-2 was capable of folding the lower wings into the top ones, transforming the plane into a monoplane fighter capable of reaching higher speeds. The IS-2 is a further development of the IS-1, the original aircraft with a lighter armament, weaker engine, and different tail surfaces. Let’s find out more about how the story of these forgotten aircraft!
History
Spoiler
The idea of the Soviet IS, standing for Istrebitel skladnoi, or folding fighter, was conceived by Vladimir Shevchenko in partnership with Vasili Nikitin. Shevchenko’s thinking behind this idea was that the aircraft could take off as a biplane, but be able to fold its landing gear and lower wings to become a monoplane. As such, Shevchenko began promoting the concept in November 1938, and in 1939, a working model of the aircraft was displayed at the Air Force Academy named after N.E. Zhukovsky, today’s Zhukovsky Air Force Engineering Academy, in Moscow. Among those interested by the design were none other than Stalin and Beria. Shevchenko’s team was given 76 million rubles and facilities at Factory No.156 for a airworthy aircraft to be ready by the October Revolution parade in November of 1939. Despite this, it did not meet the deadline, and the sole prototype built would only fly the following year, piloted by V Kuleshov on May 29th, 1940.
During testing, it was found that the plane could indeed fold its wings mid-flight, with a recorded time of about 7 to 10 seconds for completion. Following the aircraft’s takeoff, the pilot would employ a pneumatic system to retract the landing gear. Another lever for folding the wings could then be selected. This lever was operated by a pneumatic ram and hinged levers on both sides, initiating the folding of the lower wing. The inner portion of the wing would retract into the fuselage, while the hinged outer section would fold into the upper wing, thereby achieving its streamlined airfoil configuration.
Ultimately, the aircraft was cancelled due to its low speed even in its monoplane form. There were also several issues, one of which being that when the four ShKAS machine guns fired while the wings were folded, there was nowhere for the spent cartridges to escape.
While the IS-1 had failed, there was still enough funding for the project to create a second variant. Seizing on the opportunity, Shevchenko’s team began design work on the IS-2. Intended as a more refined IS-1, the IS-2 used an 1,100 hp M-88 engine driving a VISh-23 propeller and a large spinner. The aspect ratio was increased and the area was reduced. The landing gear system was replaced by simply connecting the main legs to the wing linkage, allowing both the landing gear and the lower wings to be folded. Other modifications was a redesign of the tail, and the tailwheel could retract into the fuselage. The aircraft’s armament was improved from the IS-1, with two of the inboard ShKAS machine guns being replaced by 12.7mm Berezin BS machine guns.
In early 1941, a prototype was ready, however whether the aircraft had had a test flight is debated, with one account stating it had four test flights before Operation Barbarossa, and three others stating it was ready in April 1941, but had not flown by the time the Germans invaded. Regardless, the low speed of the IS-2 compared to the faster, more streamlined monoplane designs entering service with the Red Air Force resulted in the IS-2 being left in the annals of history. While the folding fighter design was not a success, Shevchenko would continue to design, though not build, aircraft on this concept until 1947.
Soviet I-153 “Chaika” fighters of the 32nd Fighter Aviation Regiment over Sevastopol, 1941.
Specifications
Spoiler
- Wingspan (upper): 8.6 m (28 ft 3 in)
- Wingspan (lower, extended): 6.72 m (22 ft 4 in)
- Wing area (biplane): 20.83 m² (224 ft²)
- Wing area (upper wings): 13 m² (140 ft²)
- Length: 7.10 m (23 ft 4 in)
- Weight: 2,810 kg (6,195 lb)
- Armament: 2× 12.7mm Berezin BS & 2x 7.62mm ShKAS
- Engine: 1,100 hp 14-cylinder M-88 radial engine
- Maximum speed: 507 km/h (315 mph)
Sources
Spoiler
- Gordon, Yefim, and Bill Gunston. Soviet X-Planes. Midland, 2000.
- Nikitin-Shevchenko IS-2 - experimental fighter
- Уголок неба ¦ Шевченко, Никитин ИС-1(2)
- https://topwar.ru/171793-boevye-samolety-letajuschij-is-1.html
Pictures
