The Nikitin-Schyevchyenko IS series, (''Istrebitel Skladnoi'' – folding fighter), were single seat polymorphic fighters designed and produced in the

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...

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 planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

fighter. Assisted by Nikitin in his investigation, Schyevchyenko built a scale model at MAT in 1939. Later in 1939

OKB-30 Bratukhin, or OKB-3, was a Soviet aircraft design bureau created in 1940 from within TsAGI to develop helicopters. Headed by Ivan Pavlovich Bratukhin, the bureau built several experimental helicopters over the next decade. Each model had the same ba ...

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 ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

forward of the

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

, wing

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

booms and the combined lower inner wing and undercarriage 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-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

throughout except for fabric covering on the control surfaces. The

pneumatically Pneumatics (from Greek ‘wind, breath’) is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and e ...

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 (russian: Микоян и Гуревич МиГ-3) was 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 Departme ...

and

Yak-1 The Yakovlev Yak-1 (russian: Яковлев Як-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, ...

. 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 (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

invasion in 1941. Even more powerful versions were designed with AM-120 or AM-37 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, 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