The Nikitin-Schyevchyenko IS series (, meaning "folding fighter"), were single seat polymorphic fighters designed and produced in the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

from 1938.

Development

Nikitin's test pilot, Vladimir Vasiloyevich Schyevchyenko, investigated the practicality of a biplane fighter with a folding lower wing which retracted into the upper wing. The intention being to combine the short field length and climb capabilities of the

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

with the speed of the

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

fighter. Assisted by Nikitin in his investigation, Schyevchyenko built a scale model at

MAT A mat is a hard or soft floor covering that generally is placed on a floor or other flat surface. Mats serve a range of purposes including: * serving to clean items passed over it, such as a doormat, which removes dirt from the soles of shoe ...

in 1939. Later in 1939 OKB-30 were tasked with the design and manufacture of the full-scale IS, which was completed by 6 November 1940. The

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

forward of the

cockpit A cockpit or flight deck is the area, on the front part of an aircraft, spacecraft, or submersible, from which a pilot controls the vehicle. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls th ...

, wing spar booms and the combined lower inner wing and

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

assemblies were built up from welded 30KhGSA steel tubing, whilst the rest of the airframe was constructed from D16

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...

throughout except for fabric covering on the control surfaces. The

pneumatically Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically- ...

actuated inwards retracting undercarriage was housed inside the inner lower-wing which folded at approx ½ span to lie in recesses in the sides of the fuselage. The outer halves of the lower wings remained horizontal as the wings retracted and were housed in recesses in the under-surfaces of the upper wings. Retraction of the wings was carried out by a single vertically mounted pneumatic actuator in the fuselage which unlocked the bracing struts either side and pulled the wing upwards as the bracing strut was pulled upwards. Control of the undercarriage retraction and wing folding was accomplished with a single three position lever in the cockpit. With 'Chassis Down' selected the wing and undercarriage were extended, selecting 'Chassis Up/Wing Down' retracted the undercarriage into the inner lower wing, and selecting 'Wing Up' retracted the wing, selection of wing position could be made at any time to enable the pilot to choose the best configuration for the situation the aircraft was in."The Annals Of The Polymorph – A short history of V-G", Air International/March 1975, page 138-140 Flight tests were successful but the performance of the monoplane configuration was inferior to the contemporary monoplane fighters such as the

MiG-3 The Mikoyan-Gurevich MiG-3 () is a Soviet fighter- interceptor used during World War II. It was a development of the MiG-1 by the OKO (opytno-konstruktorskij otdel — Experimental Design Department) of Zavod (Factory) No. 1 in Moscow to rem ...

and

Yak-1 The Yakovlev Yak-1 () was a Soviet fighter aircraft of World War II. The Yak-1 was a single-seat monoplane with a composite structure and wooden wings; production began in early 1940.Angelucci and Matricardi 1978, p. 239. The Yak-1 was a man ...

. A second machine was built fitted with a more powerful engine but flight tests were interrupted by the

German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

invasion in 1941. Even more powerful versions were designed with

AM-120 USS ''Sway'' (AM-120) was an acquired by the United States Navy for the dangerous task of removing mines from minefields laid in the water to prevent ships from passing. ''Sway'' was laid down on 18 November 1941 by John H. Mathis & Company, ...

AM-37 The Mikulin AM-37 was a Soviet aircraft piston engine designed prior to Russia's entry into World War II. An improved version of the Mikulin AM-35 V-12 engine, it was only produced in small numbers because of its unreliability. Development Desig ...

engines, however the invasion forced abandonment of the concept.

Variants

* IS-1 – Initial prototype with M-63 (Ash-63) factory tests completed, LII flight test carried out by

G.M. Shiyanov GM or Gm may refer to: Companies * General Motors, US automobile manufacturing company which was founded in 1908 ** Motors Liquidation Company, the US automobile manufacturing company known as General Motors Corporation from 1916 to 2009 * ...

, armed with 4x

ShKAS The ShKAS (Shpitalny-Komaritski Aviatsionny Skorostrelny, Shpitalny-Komaritski rapid fire for aircraft; Russian: ШКАС - Шпитального-Комарицкого Авиационный Скорострельный) is a 7.62 mm calibre ...

in the roots of the upper main-plane, synchronised to fire through the propeller. * IS-2 – The second airframe with improvements and M-88 engine in a long-chord NACA cowling, armed with 2x BS and 2x ShKAS. * IS-3 – Projected version, no information available. * IS-4 – Final design version with AM-120 or AM-37 engine, refined aerodynamics and tricycle undercarriage.

Specifications (IS-1)

References

Bibliography

* Green, William and Gordon Swanborough. "Ingenious and Innovative, but...! The 'Folding Fighters' of the 'Forties". ''Air Enthusiast Quarterly'', No. 2, n.d., pp. 186–190. * Gunston, Bill. "Encyclopaedia of Russian Aircraft 1875-1995". London:Osprey. 1995. http://issuu.com/jeanlulu/docs/-aviation--soviet-x-planes--yefim-gordon---bill-gu

External links