The Chyetverikov ARK-3 (''ARKtichyeskii'' - arctic) was a multi-role flying boat designed for Arctic operations that was built in the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

from 1933. It featured a conventional flying boat hull, with high

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cant ...

wings equipped with floats at mid-span. The two

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common fea ...

s were mounted in tractor-pusher fashion on a pylon above 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 ...

Development

In 1933 Chyetverikov had the design for a compact twin engined flying-boat ready for further development, which he proposed to the Glavsyevmorput (''Glavsyevmorput'' – chief administration of northern sea routes) as a multi-role Arctic aircraft, and an order for a prototype was made, setting up Chyetverikov in his own

OKB OKB is a transliteration of the Russian initials of "" – , meaning 'experiment and design bureau'. During the Soviet era, OKBs were closed institutions working on design and prototyping of advanced technology, usually for military applications. ...

(design bureau). The ARK-3 was of mixed construction, with a long Duralumin stressed skin fuselage; wooden wings of MOS-27 aerofoil section; duralumin tubing tail surfaces; and ailerons with fabric covering. The dual control enclosed cockpit housed two pilots sided by side with two gunners/observers in bow and dorsal positions. Strut-supported wooden floats, at approximately half-span; and a pylon-supported engine nacelle housing tandem radial engines with

Townend ring A Townend ring is a narrow-chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling. Development The Townend ring was the invention of Dr. Hubert Townend of the British National Physical ...

cowlings; completed the structural elements, built with a safety factor of 5.5. Flight- and sea trials in 1936 revealed weaknesses in the bows, floats and engine nacelle pylon, which were all strengthened. Performance was deemed to be good, prompting an order for a second prototype with the fuselage lengthened by to and a slightly enlarged wing; this was designated ARK-3-2 and the first prototype was re-designated ARK-3-1. A production order for five aircraft was placed, with production commencing immediately. On 14 July 1937 the ARK-3-1 was destroyed following a structural failure; the ARK-3-2 was destroyed exactly one year later and the programme was cancelled.

Variants

;ARK-3-1:The first prototype ARK-3 renamed after the second prototype was ordered ;ARK-3-2:The second prototype ARK-3 with more powerful engines, longer hull, increased wing chord and manual guns fitted in a manual gun turret in the bows and a dorsal sliding hatch. ;ARK-3 MP2:Designation of the five production aircraft and the initial designation of the first prototype.

Specifications (ARK-3-2)

References

* Angelucci, Enzo. ''The Rand McNally Encyclopedia of Military Aircraft, 1914-1980''. San Diego, California: The Military Press, 1983. Pg. 311 . * Gunston, Bill. ''The Osprey Encyclopaedia of Russian Aircraft 1875 – 1995''. London, Osprey. 1995. * Taylor, Michael J.H. . ''Jane's Encyclopedia of Aviation''. Studio Editions. London. 1989. {{Soviet transport designations 1930s Soviet patrol aircraft Flying boats Chyetverikov aircraft Twin-engined push-pull aircraft High-wing aircraft Aircraft first flown in 1936